431f-432f

Training Manual Green Anode Plant Vedanta - Jharsuguda

138-02-043 Group 431/432 F

DE-060300

13 PROCESS GROUP 431/432 F - BALL MILL SYSTEM-

13 Process Group 431/432 F - Ball Mill System-..............................................................................1 13.1 Process .......................................................................................................................................1 13.1.1 Process Flow Sheets...................................................................................................................1 13.1.2 Brief Process Description ............................................................................................................2 13.1.3 Main Process Data & Process Highlights ....................................................................................3 13.2 Process Control .........................................................................................................................10 13.2.1 P&Id`s, Operator Screen Images ..............................................................................................10 13.2.2 Control Logic Description ..........................................................................................................11 13.3 Main Equipment ........................................................................................................................12 13.3.1 Belt Weigh Feeder 431/432 F 010 ............................................................................................12 13.3.2 Double Pendulum Flap 431/432 F 025......................................................................................12 13.3.3 Ball Mill 431/432 F 100..............................................................................................................12 13.3.4 Dynamic Classifier 431/432 F 210 ............................................................................................12 13.3.5 Cyclone 431/432 F 215 .............................................................................................................12 13.3.6 Throttle Flap (motorized) 431/432 F 240...................................................................................12 13.3.7 Circulation Fan 431/432 F 245 ..................................................................................................12 13.3.8 Drum-Type Magnetic Separator 431/432 F 265........................................................................12 13.3.9 Impact Flow Meter 431/432 F 275.............................................................................................12 13.3.10 Automatic Sampler (pneumatic) 431/432 F 310........................................................................12

13.1 Process

13.1.1 Process Flow Sheets

(Work Copy)

Outokumpu Technology GmbH Revision: 0 Date: 29.09.2006file: 138-02-043_13_0.doc, Codeword: Vedanta of 12


138-02-043 Group 431/432 F

DE-060300

Outokumpu Technology GmbH Revision: 0

Date: 29.09.2006Page 2 of 12 file: 138-02-043_13_0.doc, Codeword: Vedanta

13.1.2 Brief Process Description

(Work Copy)

CONTROL PHILOSOPHY 05.10.2006

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Vedanta Alumina Ltd. Jharsuguda – Green Anode Plant Client ref.: VJ/SML/PO/032/1 OTK ref.: DE-060300 Doc. No.: 133-50-070

Rev. 00

Brief Process Description of

Process Group 431-F - Ball Mill System -

Reference:

Process Flow Sheet 132-01-082 UB

P+I Diagrams 168-01-062 UB, sheets 1-3

The process is described in order to the material flow whereas the control philosophy is written in order to the signal flow, which is counter current to the material flow.

This Process Group is required to produce a very fine petroleum coke fraction (grain size 0-03mm with max. 75% <0.074mm) called “Ball Mill Fraction” which is used as filler material of the dry mix to be blend in Group 431 H. This very fine material is ground by a ball mill (431 F 100) of the air-swepped type working in a closed conveying air circuit.

The feed material is continuously withdrawn from the storage bin (431 A 320) by means of belt-weigh-feeder (431 F 010). The flat slide gate (431 F 005) under the storage bin is always open except if maintenance has to be done on the weigh-feeder underneath.

The material is continuously fed to the ball mill passing a reversing flap (431 F 015), a screw conveyor (431 F 022) and a double-pendulum flap (431 F 025). The double pendulum flap is required because the ball mill air circuit and thus the ball mill are working under negative pressure. If the weigh-feeder has to be calibrated, the material can be directed into a bulker bag by manually tilting the reversing flap (431 F 015) for a certain time and weighing the bag later on a platform scale (431 H 096).

In the ball mill (431 F 100) the feed material is ground by steel balls while the coke is slowly passing the ball mill tube. The mill is capable to achieve a product grain size of about 0-2mm containing a large portion of 0- 0.074mm size (- 200 mesh).

The circulating air flow, generated by a fan (431 F 245), is passing the mill tube and carries the ground material via a vertical duct into the airflow classifier (431 F 210) where oversized material (> 0.3mm) is separated, which is recycled to the ball mill and via rotary lock (431 F 260) and impact flow meter (431 F 275).

A drum magnet (431 F 265) with permanent magnet is removing fine ground iron (abration loss of the grinding balls) and also small iron particles coming with the raw material, coke.

The air flow classifier is equipped with a number of adjustable baffles, concentrically located around a motor driven cage wheel. Both baffles and cage wheel are making the air flow rotating so that coarse particles are separated at the inner wall and in the separator center by centrifugal force while the finer product is leaving the classifier through the top outlet. The cutpoint of the classifier is adjustable by a variable speed drive for the cage wheel and by adjusting the baffles.

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Material of required grain size (0-0.3mm) is transported by air flow to the cyclone (431 F 215) where the fine ground coke is separated from the carrying air flow. Via a rotary lock (431 F 305) the fine ground material is discharged from the cyclone, is then passing an automatic sampler (431 F 310) and is finally falling either into the “fines” bin (431 F 400). If the reversing flap (431 F 325) is switched to the other way, the material is fed to the screw conveyors (431 F 330 / 335) it is conveyed into the “Fresh Adsorbent” bin (431 F 450). Between automatic sampler (431 F 310) and reversing flap (431 F 325) is another reversing flap, for fed the ground material in the first 10 minutes after starting the Ball Mill System via screw conveyor (431 F 323) in the Filter Dust Bin (431 C 100). The reason for this procedure is the unsteady quality of the ground material during the start phase of the ball mill.

The air flow leaving the cyclone (431 F 215) is passing the fan (431 F 245) via a motorized throttle flap (431 F 240), which is closing before start up of the fan and is then opened to a preset angle to adjust the flow rate.

The throttle flaps (431 F 250 / 255) downstream the fan are used to split the air flow to be send through the mill and through the mill bypass duct.

A part of the circulation air is withdrawn by a dust collector fan (431 F 230) via a throttle flap (431 F 225) and through a dust collector (431 F 220) in order to reduce the dust content in the circulating air and to keep the circulation air system at negative pressure in order to avoid dust leaks.

Dust separated by the dust collector (431 F 220) is discharged via a rotary lock (431 F 315) and a screw conveyor (431 F 320) into either the “Ball Mill Fraction” bin (431 F 400) or into the bin for “Fresh Adsorbent” (431 F 450).

With the ball mill operating, filter dust is continuously reclaimed from the “Filter Dust” bin (431 C 100) by means of the rotary lock (431 F 055), which is equipped with a variable speed drive so that the feed rate is adjustable. An aeration unit (431 F 051) installed at the “Filter Dust” bin bottom avoids bridging of material in the bin. The filter dust is added to the air flow which is entering the air flow classifier (431 F 210). Filter Dust is only fed to the system when the Ball Mill System is producing.

Loaded adsorbent from Group 431 G is continuously discharged from the “Loaded Adsorbent” storage bin by means of the rotary lock (431 F 355), which is equipped with a variable speed drive so that the feed rate is adjustable. An aeration unit (431 F 351) installed at the “Loaded Adsorbent” bin bottom avoids bridging of material in the bin. The material is added to the chute feeding the Ball Mill Fraction bin (431 F 400). Loaded Adsorbent is only then fed to the Ball Mill Fraction bin as long as the bin is filled with fresh Ball Mill Product and is stopped when the Fresh Adsorbent bin is filled.

For calibration of the rotary lock for Filter Dust (431 F 055) material is fed via the reversing flap (431 F 060) into a bulker bag (431 F 285). The bulker bag has to be weighed on a platform scale (431 H 096). Calibration of the impact flow meter (431 F 275) is via reversing flap (431 F 280). Only during automatic run of the complete Group it is possible to switch the reversing flap (431 F 280) for a short while to the bulker bag.


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13.1.3 Main Process Data & Process Highlights

Date: 29.09.2006file: 138-02-043_13_0.doc, Codeword: Vedanta Page 3 of 12

There are various ball mill systems working in green anode plants.

1) The simplest one, shown in figure 1, is an open system consisting of a ball mill and a bucket elevator. The mill is continuously fed through the left trunnion bearing and is also continuously discharged through the right bearing by simply overflowing into a bucket elevator.

Advantages:

- Lowest investment cost - Simple to operate - Low maintenance costs

Disadvantages:

- Relatively large mill because of low specific production rate. - Significant part of fines over-ground (high super fines content) - High specific energy consumption because of over-grinding - Relatively high jamming (overflowing) risk - Product size controlled by feed rate only, not by grain size - Environment problems with dust (ball mill, bucket elevator)

The main disadvantage is uncontrolled over-grinding of fines. Fines, which is produced in the first third of the grinding path, has particles already acceptable in size. The material is forced to be transported through the next two thirds of the grinding path of the mill before it is discharged. It is most likely that already fine grains are milled to finer size as required. For the process of anode making this requires more pitch because of the larger surface area.

Over-grinding is in principle due for all overflow ball mills.


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2) Figure 2 is showing a more advanced closed system with overflow ball mill, bucket elevator and dynamic classifier. Oversize material is separated by the classifier and returned to the mill.

Advantages:

- Relatively low investment cost - Still simple to operate - Good control of product grain size (dynamic classifier and feed rate) - Higher specific production rate as open systems - Lower specific energy consumption as open systems

Disadvantages:

- Part of fines over-ground (significant uncontrolled super fines content) - Higher maintenance costs (mill, bucket elevator, classifier - High specific energy consumption because of over-grinding - Relatively high jamming (overflowing) risk - Product size controlled by feed rate and re-circulation only, not by grain size - Environmental problems with dust (ball mill, bucket elevator, classifier)

3) Figure 3 is showing an often used closed system with overflow ball mill, static or dynamic air flow classifier, a dust collector and a fan working as an air lift.

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138-02-043 Group 431/432 F

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Advantages:

- Still simple to operate - Good control of product grain size (static / dynamic classifier and feed rate) - Higher specific production rate - Lower specific energy consumption

Disadvantages:

- Relatively high investment cost - Part of fines over-ground (significant uncontrolled super fines content) - Higher maintenance costs (mill, classifier, dust collector, fan) - Environmental problems with dust (ball mill)


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4) Figure 4 is showing a typical closed air swept system with air swept ball mill, static or dynamic air flow classifier, circulation fan, cyclone and dust collector / fan unit as installed at VEDANTA. This is the most advanced ball mill system nowadays. The airflow through the mill is adjustable. Grain of the desired product size, wherever generated is immediately carried off the mill body by air stream. There is no over-grinding. Product fineness below 200mesh can be in a certain range controlled by air velocity in the mill body.

Advantages:

- Simple to operate but relatively difficult to adjust - Good control of product grain size (static / dynamic classifier and feed rate) - Highest specific production rate - Lowest specific energy consumption - No over-grinding of mill product because air stream through mill body carries

already ground material continuously out. - No environmental problems with dust because whole system is at under-pressure.

Disadvantages:

- Higher investment cost (additional cyclone, fan and air ducts) - Higher maintenance costs (mill, classifier, cyclone, dust collector, two fans, air

flaps) • •

•

The process group is designed for a maximum “Fines” production rate of 12 t/hour. At worst operating condition (No Butts) the “Ball Mill Fraction” requirement is 8.9 t/h. At this worst condition it was assumed that no recycled butts are available so that petroleum coke has to be used instead At operating condition “Nominal Butts AA” the “Ball Mill Fraction” requirement is 7.9 t/h only.



138-02-043 Group 431/432 F

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During commissioning VEDANTA operating personnel has to decide at what capacity and product grain size the mill system should operate. If for instance the capacity shall be 10.0 t/hour at a product grain size of 75% < 200mesh then the mill body is filled with the ball charge but not to the maximum of 29% of the mill volume, equal to 36 tons of balls as possible. The first filling would be 70% of 29% = 20.3 % of mill volume only and then the system is started feeding only 8 t/hour of fresh coke to the mill. Then samples are taken from the cyclone product and if the product size is too fine, as expected, the feed rate is increased step by step until the product becomes too coarse. Now the next charge of balls is added to the mill in the same distribution as before until 80% of the maximum ball charge is reached followed by similar test runs. This will be repeated until the required capacity and product size is reached. From this moment the ball mill system should always be operated at the same feed rate. If it runs at a significant lower feed rate the fines content increases and if it runs at a significant higher feed rate the fines content decreases. If it is decided to run the mill system at a higher capacity but with the same fineness of the product, more balls have to be added but never more as 29% of the mill volume or 36 tons of balls in total.

• Feed material is petroleum coke of 32 – 46 Hardgrove A Hardgrove index of 32 is not very likely when running the mill with calcined petroleum coke only. It is just a design figure for sizing the ball mill. The lower the index the harder is it to grind and the more grinding energy is required. Calcined petroleum coke mainly have Hardgrove indexes of 40 and higher.



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Feed material comes from:

“Ball Mill Feed” bin 0-6mm 1.5 – 15 t/h Feed rate can be controlled by belt weigh feeder, electronic ear and impact flow meter for recycled material from air flow classifier.

• Ball Mill Product size (into fines fraction bin):

Design < 0.075mm 75 +/-2 % Normal < 0.075mm 65 to 70 +/-2 % Total range adjustable < 0.075mm 55-75 +/-2 %

The product size is mainly determined by: 1. Cut point of the air flow classifier 2. Retention time of material in the mill tube (depends on: feed rate, re-circulation rate

of oversize) 3. Air velocity through mill tube 4. Grinding ball charge (total weight and size distribution of balls) 5. Feed material size distribution

The finer the ball mill product shall be milled the more specific grinding work is required as the following equation shows:

inDoutDW 80/180/1 −=

W = specific grinding work D80out = product grain size at 80% passing D80in = feed grain size at 80% passing Because each ball mill is designed for a maximum specific grinding work and product fineness there is a capacity limit. If finer product is required it can be achieved by readjusting the cut point of the airflow classifier and by reducing the feed rate of fresh material at the same time. If only the cut point of the classifier is changed to a smaller size without reducing the feed rate then the amount of oversize returned to the mill is increasing. This would only raise with each air cycle more and more the material level in the mill until the material overflows the mill at the discharge end. During automatic operation of the mill level control system overflowing of the mill should be impossible because the flow meter and the sonic ear control the feed rate automatically.



138-02-043 Group 431/432 F

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The feed size has also a significant impact on the product size of a ball mill system. It would be ideal to feed continuously the same rate of coke to the mill but this cannot be achieved all time. If the feed rate of one fraction has to be changed because there is a lack or a surplus of material in the Ball Mill Feed bin the change should be moderate. If a lot filter dust has been added to the Ball Mill Feed bin the product grain size is shifted to a finer size immediately because filter dust is much finer as ball mill dust and so is taken directly by the air stream out of the mill body. If much Fine Coke (3-6 mm) has been fed to the Ball Mill Feed bin then the ball mill product is finally coarser than usual.

•

•

Ball mill: Manufacturer: McNally Bharat Engineering Co. Limited Size: 2.60m dia x 5.75m long

Dynamic Air Flow Classifier: Manufacturer: HUMBOLDT WEDAG INDIA PVT. LTD. Type: SKS-L 1300 cut point: adjustable by cage wheel speed and baffle adjustment



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13.2 Process Control

13.2.1 P&Id`s, Operator Screen Images

(work copies)



138-02-043 Group 431/432 F

DE-060300


Date: 29.09.2006file: 138-02-043_13_0.doc, Codeword: Vedanta Page 11 of 12

13.2.2 Control Logic Description

(Work Copy)


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Rev. 00

Control Philosophy of

Process Group 431-F - Ball Mill System -

Reference:

Process Flow Sheet 132-01-082 UB

P+I Diagrams 168-01-062 UB, sheets 1-3

1 Brief Process Description............................................................................................................ 2 2 Control Logic Description............................................................................................................ 3 2.1 Special Terminology for this Group.............................................................................................3 2.2 Process Groups Linked with this Group...................................................................................... 3 2.3 Selection ..................................................................................................................................... 4 2.3.1 Operation Mode of the Group (SE 1) .......................................................................................... 4 2.3.2 Material Route (SE 2).................................................................................................................. 4 2.3.3 Autosampler 431 F 310 (SE 3).................................................................................................... 4 2.3.4 Filter Dust (SE 4)......................................................................................................................... 5 2.3.5 Ball Mill Level (SE 5) ................................................................................................................... 5 2.3.6 Throttle Flap 431 F 240 (SE 6).................................................................................................... 7 2.3.7 Reversing Flap 431 F 322 (stable operation of ball mill system) (SE 7) ..................................... 7 2.4 Group Start ................................................................................................................................. 7 2.4.1 Selections Prior to Start .............................................................................................................. 7 2.4.2 Start Preconditions...................................................................................................................... 7 2.4.3 Setpoints Prior to Group Start ..................................................................................................... 9 2.4.4 Group Start Sequence .............................................................................................................. 11 2.4.5 Restarting the Group................................................................................................................. 13 2.5 Normal Operation...................................................................................................................... 13 2.6 Group Shut Down ..................................................................................................................... 17 2.6.1 Normal Shut Down.................................................................................................................... 17 2.6.2 Shut Down by Other Groups..................................................................................................... 18 2.6.3 Fast Shut Down......................................................................................................................... 18 2.6.4 Trip in Case of Faults ................................................................................................................ 19 2.6.5 Shut Down by Full Bins............................................................................................................. 26 2.7 Local Operation of Special Equipment...................................................................................... 27 2.8 Signal Exchange with Sub-Groups of this Group and Other Process Groups .......................... 28



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Rev. 00

1 BRIEF PROCESS DESCRIPTION

The process is described in order to the material flow whereas the control philosophy is written in order to the signal flow, which is counter current to the material flow.

This Process Group is required to produce a very fine petroleum coke fraction (grain size 0-03mm with max. 75% <0.074mm) called “Ball Mill Fraction” which is used as filler material of the dry mix to be blend in Group 431 H. This very fine material is ground by a ball mill (431 F 100) of the air-swepped type working in a closed conveying air circuit.

The feed material is continuously withdrawn from the storage bin (431 A 320) by means of belt-weigh-feeder (431 F 010). The flat slide gate (431 F 005) under the storage bin is always open except if maintenance has to be done on the weigh-feeder underneath.

The material is continuously fed to the ball mill passing a reversing flap (431 F 015), a screw conveyor (431 F 022) and a double-pendulum flap (431 F 025). The double pendulum flap is required because the ball mill air circuit and thus the ball mill are working under negative pressure. If the weigh-feeder has to be calibrated, the material can be directed into a bulker bag by manually tilting the reversing flap (431 F 015) for a certain time and weighing the bag later on a platform scale (431 H 096).

In the ball mill (431 F 100) the feed material is ground by steel balls while the coke is slowly passing the ball mill tube. The mill is capable to achieve a product grain size of about 0-2mm containing a large portion of 0- 0.074mm size (- 200 mesh).

The circulating air flow, generated by a fan (431 F 245), is passing the mill tube and carries the ground material via a vertical duct into the airflow classifier (431 F 210) where oversized material (> 0.3mm) is separated, which is recycled to the ball mill and via rotary lock (431 F 260) and impact flow meter (431 F 275).

A drum magnet (431 F 265) with permanent magnet is removing fine ground iron (abration loss of the grinding balls) and also small iron particles coming with the raw material, coke.

The air flow classifier is equipped with a number of adjustable baffles, concentrically located around a motor driven cage wheel. Both baffles and cage wheel are making the air flow rotating so that coarse particles are separated at the inner wall and in the separator center by centrifugal force while the finer product is leaving the classifier through the top outlet. The cutpoint of the classifier is adjustable by a variable speed drive for the cage wheel and by adjusting the baffles.

Material of required grain size (0-0.3mm) is transported by air flow to the cyclone (431 F 215) where the fine ground coke is separated from the carrying air flow. Via a rotary lock (431 F 305) the fine ground material is discharged from the cyclone, is then passing an automatic sampler (431 F 310) and is finally falling either into the “fines” bin (431 F 400). If the reversing flap (431 F 325) is switched to the other way, the material is fed to the screw conveyors (431 F 330 / 335) it is conveyed into the “Fresh Adsorbent” bin (431 F 450). Between automatic sampler (431 F 310) and reversing flap (431 F 325) is another reversing flap, for fed the ground material in the first 10 minutes after starting the Ball Mill System via screw conveyor (431 F 323) in the Filter Dust Bin (431 C 100). The reason for this procedure is the unsteady quality of the ground material during the start phase of the ball mill.

The air flow leaving the cyclone (431 F 215) is passing the fan (431 F 245) via a motorized throttle flap (431 F 240), which is closing before start up of the fan and is then opened to a preset angle to adjust the flow rate.



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The throttle flaps (431 F 250 / 255) downstream the fan are used to split the air flow to be send through the mill and through the mill bypass duct.

A part of the circulation air is withdrawn by a dust collector fan (431 F 230) via a throttle flap (431 F 225) and through a dust collector (431 F 220) in order to reduce the dust content in the circulating air and to keep the circulation air system at negative pressure in order to avoid dust leaks.

Dust separated by the dust collector (431 F 220) is discharged via a rotary lock (431 F 315) and a screw conveyor (431 F 320) into either the “Ball Mill Fraction” bin (431 F 400) or into the bin for “Fresh Adsorbent” (431 F 450).

With the ball mill operating, filter dust is continuously reclaimed from the “Filter Dust” bin (431 C 100) by means of the rotary lock (431 F 055), which is equipped with a variable speed drive so that the feed rate is adjustable. An aeration unit (431 F 051) installed at the “Filter Dust” bin bottom avoids bridging of material in the bin. The filter dust is added to the air flow which is entering the air flow classifier (431 F 210). Filter Dust is only fed to the system when the Ball Mill System is producing.

Loaded adsorbent from Group 431 G is continuously discharged from the “Loaded Adsorbent” storage bin by means of the rotary lock (431 F 355), which is equipped with a variable speed drive so that the feed rate is adjustable. An aeration unit (431 F 351) installed at the “Loaded Adsorbent” bin bottom avoids bridging of material in the bin. The material is added to the chute feeding the Ball Mill Fraction bin (431 F 400). Loaded Adsorbent is only then fed to the Ball Mill Fraction bin as long as the bin is filled with fresh Ball Mill Product and is stopped when the Fresh Adsorbent bin is filled.

For calibration of the rotary lock for Filter Dust (431 F 055) material is fed via the reversing flap (431 F 060) into a bulker bag (431 F 285). The bulker bag has to be weighed on a platform scale (431 H 096). Calibration of the impact flow meter (431 F 275) is via reversing flap (431 F 280). Only during automatic run of the complete Group it is possible to switch the reversing flap (431 F 280) for a short while to the bulker bag.

2 CONTROL LOGIC DESCRIPTION

2.1 Special Terminology for this Group

There is no special terminology for this group.

2.2 Process Groups Linked with this Group

The following Process Groups are linked with this Group 431 F:

• Main Dust Treatment 431 C

The exchange of control signals is described in the following chapters and especially under 2.8 below.



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2.3 Selection

2.3.1 Operation Mode of the Group (SE 1)

The operator has two options: The selection is made on the Operator Station located in the Central Control Room (CCR). Selection and indication of the state of selection is on SCADA.

“CENTRAL” operation mode” After this selection this Group is ready to start in CENTRAL operation mode, if all preconditions (see 2.4.2) below are fulfilled.

“LOCAL” operation mode” (details please see under 2.7 below)

2.3.2 Material Route (SE 2)

The operator has two options: The selection is made on the Operator Station located in the Central Control Room (CCR). Selection and indication of the state of selection is on SCADA and can be changed any time.

SE 2-1 - “Ball Mill Fraction Bin” This is the selection used most of the time. At this selection Ball Mill Product will be fed to the Ball Mill Fraction bin (431 F 400).

SE 2-2 - “Fresh Adsorbent Bin” This selection is used only if the Fresh Adsorbent bin (431 F 450) has to be refilled. At this selection Ball Mill Product will be fed to the Fresh Adsorbent bin.

SE 2-3 - “Auto Select” This selection enables automatic selection of the Ball Mill Feed bin and of the Fresh Adsorbent bin. The selection depends on the actual material level in the bins.

SE 2-4 - “Manual Select” This selection disables automatic selection of the Ball Mill Feed bin and of the Fresh Adsorbent bin.

2.3.3 Autosampler 431 F 310 (SE 3)

The operator may initiate taking a sample at any time. The selection is made on the Operator Station located in the Central Control Room (CCR). Selection and indication of the state of selection is on SCADA.

SE 3-1 - “Auto Sample” This selection enables automatic sampling of the ball mill product. Sampling is controlled by a software timer.

SE 3-2 - “Manual Sample” This selection disables automatic sampling of the ball mill product. Sampling is controlled by the operator. Clicking the “Sample” button on SCADA will initiate one sampling cycle.



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SE 3-3 - “Sample” If SE 3-2 is selected and the operator is clicking on the “Sample” button (SE 3-3) on SCADA a single sample is taken.

2.3.4 Filter Dust (SE 4)

The operator two options: The selection is made on the Operator Station located in the Central Control Room (CCR). Selection and indication of the state of selection is on SCADA.

SE 4-1 – “Add Filter Dust” The operator may select “Add Filter Dust” at any time as long as CENTRAL operation mode is selected and if the reversing flap (431 F 060) is in correct position [limit switch 431 F 060-ZH activated] so that Filter Dust will be fed to ball mill system air circuit.

SE 4-2 – “Filter Dust LOCAL” The operator may select “Filter Dust Local” at any time. Straight with the selection the rotary lock (431 F 055) stops feeding. Starting the rotary lock requires the reversing flap limit switch [431 F 060-ZL] to be initiated (flap to calibration). On the Local Operator Panel [431 F 060-LOP1] the pilot light [431 F 055-H2] indicates the rotary lock is stopped and thus the LOCAL operating mode is released (at “Add Filter Dust” selection all pilot lights on the local panel are off) and so are the push buttons on this local panel.

SE 4-3 – “No Filter Dust” The operator may select “No Filter Dust” at any time as long as CENTRAL operation mode is selected so that no Filter Dust will be fed to ball mill system air circuit.

2.3.5 Ball Mill Level (SE 5)

The actual level of coke in the mill body is measured by a sonic level measuring system (electronic ear) [431 F 100-LY].

The material level in the ball mill can be either controlled automatically or manually by the operator.

The material level in the mill is a function of:

• the fresh coke feed rate provided by the belt weigh feeder (431 F 010) • the recycling rate of oversize material coming back from the air flow classifier (431 F 210) • the feed size of fresh coke and recycled coke • the grindability of the feed material (coke) • the mill size (grinding capacity) of the ball mill.

The grindability varies with the source of coke but is more or less fix for short term (hours / days) and the feed size (fresh and oversize) should be kept in a small range but still is a variable. The mill size is a design figure and is another fix value.

Thus for short term operation mainly the feed rate of fresh coke and oversize coke from the classifier have the main impact on the material level in the ball mill. The rate of oversize coke is a function of the feed size, the grindability and other impacts like the stability of the circulating air flow and therefore is not fix



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The higher the total feed rate is the higher is the mill level and the shorter is the retention time of material passing the mill body. A typical retention time is 15 minutes.

At low retention time (high feed rate) the chance of a coke grain to be ground to fine mill dust is relatively low while at a higher retention time (lower feed rate) the chance is much higher.

However the level control system must be able to balance the rate of fresh coke and recycled coke from the air flow classifier in order to attain the required fineness of the ball mill product.

SE 5-1 – “Auto Level” The operator may select “Auto Level” at any time as long as CENTRAL operation mode is selected.

At this selection the material level in the mill is controlled automatically by variation of the feed rate of belt weigh feeder (431 F 010) using the following command variables:

• electronic ear [431 F 100-LY] – material level - • impact flow meter [431 F 275-FY] – recycled material -

Both are input variables for a software-type PID Controller, which delivers the control value [431 F 010-FY] for the belt weigh feeder (431 F 010).

SE 5-2 – “Auto Electronic Ear” The operator may select “Auto Electronic Ear” at any time as long as CENTRAL operation mode is selected.

At this selection the material level in the mill is controlled automatically by variation of the belt weigh feeder (431 F 010) feed rate using the following command variable:

• electronic ear [431 F 100-LY] – material level -

At this selection this is the only input variable for a software-type PID Controller, which delivers the control value [431 F 010-FY] for the belt weigh feeder (431 F 010). In this case the impact flow meter is just used for display of the recycled material flow rate.

SE 5-3 – “Auto Flow Meter” The operator may select “Auto Flow Meter” at any time as long as CENTRAL operation mode is selected. At this selection the total feed rate, fresh feed from the belt weigh feeder plus recycled material from the air flow classifier shall be kept constant automatically while the material level in the mill is only displayed but not controlled. The command variable in this case is:

• impact flow meter [431 F 275-FY] – recycled material -

In this case the electronic ear is just used for display of the material level in the mill but shuts off the belt weigh feeder, if the level increases too much or gives alarm, if the level is too low.

SE 5-4 – “Manual Level” The operator may select “Manual Level” at any time as long as CENTRAL operation mode is selected.

• At this selection the material level in the mill is controlled manually by the operator using the Operator Station in the Central Control Room.



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In this case the electronic ear is just used for display of the material level in the mill but shuts off the belt weigh feeder when the level increases too much and for display of the flow of recycled material the impact flow meter is used.

Note: This selection shall be used for each start of this Group and shall be kept at minimum for a time of 20 minutes after the start of the ball mill (431 F 100) until the ball mill system is in stable operation.

2.3.6 Throttle Flap 431 F 240 (SE 6)

The opening of the throttle flap is determining the flow rate through the air circulation system.

SE 6-1 – “Manual Control” The operator may select “Manual Control” at any time as long as CENTRAL operation mode is selected. At this selection the operator controls the position of the flap and thus the circulating air flow.

SE 6-2 – “Auto Control” The operator may select “Auto Control” at any time as long as CENTRAL operation mode is selected. At this selection the position of the flap is controlled automatically by the PLC using the actual power consumption of the fan (431 F 245) motor as command variable.

2.3.7 Reversing Flap 431 F 322 (stable operation of ball mill system) (SE 7)

This selection shall be used for each start of this Group and shall be kept at minimum for a time of 10 minutes after the start of the ball mill (431 F 100) until the ball mill product has a steady quality.

The selection is made on the Operator Station located in the Central Control Room (CCR). Selection and indication of the state of selection is on SCADA.

The operator has two options:

SE 7-1 - “Auto Select” At this selection the ground material is fed to the filter dust bin (431 C 100) during the start phase of the ball mill (first approach for Standard Setpoint SP 7 is 10 minutes). After the start phase the ground material is fed to the ball mill fraction bin (431 F 400) or fresh adsorbent bin (431 F 450).

SE 7-2 - “Manual Select” At this selection the operator controls manually the fed of the ground material to the filter dust bin (431 C 100) or in direction to the ball mill fraction bin (431 F 400) or fresh adsorbent bin (431 F 450).

2.4 Group Start

2.4.1 Selections Prior to Start

2.4.2 Start Preconditions

“CENTRAL” operation mode must be selected.

2.4.2.1 Process Group 431 C - Main Dust Treatment



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• The Group “Main Dust Treatment” must be running in CENTRAL operation mode prior to start of this Group. It must not be tripped and not be in a stop (RESTOP or FASTOP) sequence.

2.4.2.2 Ball Mill Sub-Group 431 F 100 • If there is no “Ball Mill Sub-Group Ready” signal this Group 431 F does not start.

Note: This is a collective signal indicating that the main drive of the mill, the trunnion bearing lubrication units, the gear lube unit and the bearing jacking pumps are healthy and the inching drive is not engaged. For details please refer to the equipment documentation of the ball mill prepared by MBE.

2.4.2.3 Belt Weigh Feeder 431 F 010 • If there is no “Belt Weigh Feeder Ready” signal this Group 431 F does not start.

Note: This is a collective signal indicating the belt weigh feeder is healthy and has a sufficient material layer on the belt. For details please refer to the equipment documentation of the weigh feeder prepared by TRANSWEIGH.

2.4.2.4 Reversing Flap 431 F 015 • If the flap is not in position to feed the screw conveyor (431 F 022) and thus limit switch

[431 F 015-ZH] is not activated, this Group does not start.

2.4.2.5 Reversing Flap 431 F 280 • If the flap is not in position to feed the ball mill (431 F 100) and thus limit switch [431 F

280-ZL] is not activated, this Group does not start.

2.4.2.6 Reversing Flap 431 F 060 • If “Ball Mill Feed” (SE-2-1) is selected and if then the flap is not in position to feed the air

circulation pipe to the air-flow separator (431 F 210) and thus limit switch [431 F 060-ZH] is not activated, this Group does not start.

• If “Filter Dust Local” (SE-2-2) is selected and if then the flap is not in position to feed the bulker bag (431 F 285) and thus limit switch [431 F 060-ZL] is not activated, this Group does not start.

2.4.2.7 Ball Mill Fraction Bin 431 F 400 • If the bin (431 F 400) is full [431 F 400-LAH2 or 431 F 400-LAHH is indicating very high-or

high-high level] and if the Fresh Adsorbent bin (431 F 450) is also full [431 F 450-LAH2 or 431 F 450-LAHH is indicating very high-or high-high level] this Group does not start.

2.4.2.8 Fresh Adsorbent Bin 431 F 450 • If the bin (431 F 450) is full [431 F 450-LAH2 or 431 F 450-LAHH is indicating very high-or

high-high level] and if the Ball Mill Fraction bin (431 F 400) is also full [431 F 400-LAH2 or 431 F 400-LAHH is indicating very high-or high-high level] this Group does not start.

2.4.2.9 Emergency stops • If the Emergency Stop of the Group has been activated it has to be RESET.

2.4.2.10 Alarms • If an Alarm of this Group has been activated it has to be RESET.



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2.4.2.11 MCC`s of this Group • The MCC’s signal of this group must be OK.

2.4.2.12 “FASTOP” Signal • If a FASTOP signal is valid this Group does not start.

2.4.2.13 “RESTOP” Signal • If a RESTOP signal is valid this Group can be restarted by overriding the RESTOP signal

by the Group Start signal.

2.4.2.14 Local Control Stations • Equipment selected to run the “ON” switches must be activated.

2.4.2.15 Vibrating Screen Feeder 431 A 140 -plugged chute switch • If the plugged chute switch [431 A 140-LAH] is indicating “Plugged Chute” in the chute

above the screen feeder (431 A 140), this Group does not start.

2.4.2.16 Compressed Air Pressure 431 G 120 • Compressed air pressure in Group G [431 G 120-PAL] shall be higher than 6 bar (P>6

bar).

2.4.2.17 Medium Voltage for Ball Mill Main Drive Motor 431 F 100-M1 • If medium voltage (6.6 kV) signal is not available this Group does not start.

2.4.3 Setpoints Prior to Group Start

It makes sense to check and, if required, to readjust setpoints prior to a start of this Group.

Actual Setpoint The PLC program is storing all actually used setpoints as “Actual Setpoint” The “Actual Setpoint” is automatically used for the next start after the Group has been stopped or for a restart after the Group has tripped. The Actual Setpoint is displayed on SCADA.

New Setpoint The operator has the opportunity to override the actual setpoint by the “New Setpoint” any time Changing of setpoint is on SCADA.

Previous Setpoint Did the operator change an Actual Setpoint while the Group is running in CENTRAL mode the previous one is also stored in the PLC as “Previous Setpoint” for possible later use. The operator may override the actual setpoint by the “Previous Setpoint” at any time. Selection of the “Previous Setpoint is on SCADA.

Standard Setpoint The operator may also override the actual setpoint by the “Standard Setpoint” any time. Selection of the “Standard Setpoint” is on SCADA. The “Standard Setpoint” can be edited on the SCADA system any time but by a Shift Leader only, after using his Password.



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2.4.3.1 Throttle Flap 431 F 240 (Circulating Air Flow) (Setpoints SP 1-1 to 1-2)

This throttle flap is equipped with a servo drive for remote adjustment of the flap position.

• At Selection SE 6-1 – Manual Control - (Setpoint SP 1-1) At this selection the flap position is set by the operator. The operator may set the flap position at any time in a range of 0% to 100% [0% = limit switch position 431 F 240-ZL]. Setting and display of the actual position is on SCADA. On SCADA the operator has the choice to select one of three options, “New” setpoint, “Previous” setpoint and “Standard” setpoint all overriding the actual setpoint.

• At Selection SE 6-2 – Auto Control - (Setpoint SP 1-2) At this selection the flap position is controlled by the actual power consumption of the fan motor [431 F 245-M1]. The operator may set the power consumption of the fan at any time in a range of (??? kW – to be elaborated during commissioning -). Setting and display of the actual power is on SCADA. On SCADA the operator has the choice to select one of three options, “New” setpoint, “Previous” setpoint and “Standard” setpoint all overriding the actual setpoint.

2.4.3.2 Air Flow Classifier 431 F 210- (Setpoint SP 2) • The airflow classifier is equipped with a variable speed drive. Setting the speed of the

dynamic classifier can be done at any time but requires a password of a shift leader. The cage wheel speed can be varied between 20 % and 100 %. - 20 % 83 RPM - 100 % 416 RPM Note: It is critical to “play” with the cage rotor speed because this has great influence on the ball mill product grain size. On SCADA the operator has the choice to select one of three options, “New” setpoint, “Previous” setpoint and “Standard” setpoint (first approach for Standard Setpoint is 36%) all overriding the actual setpoint.

2.4.3.3 Rotary Lock 431 F 055 (Floor Dust) (Setpoint SP 3)

This rotary lock is equipped with a variable speed drive.

• The speed can be varied between 20 % and 100 %.corresponding a feed rate between 0.2 and 2.0 tons/hour. If “Add Floor Dust “ (SE 2-1) is selected, this feed rate can be varied any time. On SCADA the operator has the choice to select one of three options, “New” setpoint, “Previous” setpoint and “Standard” setpoint (first approach for Standard Setpoint is 50%) all overriding the actual setpoint.

2.4.3.4 Rotary Lock 431 F 355 (Loaded Adsorbent) (Setpoint SP 4)

This rotary lock is equipped with a variable speed drive.

• The speed can be varied between 20 % and 100 %.corresponding a feed rate between 0.5 and 2.5 tons/hour. Setting and display of the actual position is on SCADA at any time. On SCADA the operator has the choice to select one of three options, “New” setpoint, “Previous” setpoint and “Standard” setpoint (first approach for Standard Setpoint is 50%) all overriding the actual setpoint.



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2.4.3.5 Ball Mill Level Control System 431 F 275 (Setpoints SP 5-1 to 5-3)

The actual level of coke in the mill body is measured by a sonic level measuring system (electronic ear) [431 F 100-LY].

• At Selection SE 5-1 – Auto Level - (Setpoint SP 5-1) The target value at this selection is the material level in the ball mill tube, measured by the electronic ear [431 F 100-LY]. {Setpoint : 80%} The PLC to accept input values from the operator only between 70% and 90% (final setting during commissioning). Only the shift leader may change this setpoint by using his password.

• At Selection SE 5-2 – Auto Electronic Ear - (Setpoint SP 5-2) The target value at this selection is the material level in the ball mill tube, measured by the electronic ear [431 F 100-LY]. {Setpoint : 80%} The PLC to accept input values from the operator only between 70% and 90% (final setting during commissioning). Only the shift leader may change this setpoint by using his pass word.

• At Selection SE 5-3 – Auto Flow Meter - (Setpoint SP 5-3) The target value at this selection is the total feed rate to the ball mill (431 F 100) what is the sum of fresh feed from the belt weigh feeder plus recycled material from the air flow classifier. {Setpoint : 13 tons/hour – 1st approach}

• At Selection SE 5-4 – Manual Level - (Setpoint SP 5-4) At this selection the feed rate of the belt weigh feeder (431 F 010) is set by the operator. The operator may set the feed rate at any time in a range of 1.5 to 15.0 tons/hour. Setting and display of the actual position is on SCADA. On SCADA the operator has the choice to select one of three options, “New” setpoint, “Previous” setpoint and “Standard” setpoint all overriding the actual setpoint.

2.4.3.6 Automatic Sampler 431 F 310 – Sampler Waiting Time - (Setpoint SP 6) • The waiting time (SWT) between two samples can be set any time.

On SCADA the operator has the choice to select one of three options, “New” setpoint, “Previous” setpoint and “Standard” setpoint (first approach for Standard Setpoint is 4 hours) all overriding the actual setpoint.

2.4.3.7 Reversing Flap (431 F 322) – start phase ball mill system – (Setpoint SP 7) • The time for the start phase of the ball mill system can be varied between 5 minutes and

20 minutes. Setting the time can be done at any time. On SCADA the operator has the choice to select one of three options, “New” setpoint, “Previous” setpoint and “Standard” setpoint (first approach for Standard Setpoint is 10 minutes) all overriding the actual setpoint.

2.4.4 Group Start Sequence • The operator is enabling this Group 431 F to start and to run the selected equipment. To

initiate the start he is using the SCADA system on the Operator Station in the Central Control Room.

• Signal from Group 431 C (Main Dust Treatment) is required (Group is running in CENTRAL mode and is not in Group Start (START) or any Group Stop sequence (RESTOP or FASTOP)).



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• Signal from Sub-Group 431 F 100 required, indicating the equipment and controls of this Sub-Group is healthy. (Details please refer to machine documentation of the ball mill (431 F 100) prepared by MBE)

• The horn starts to sound permanently for 15 seconds prior to start of the first equipment, then it sounds intermittently until the last drive is running.

• Screw conveyor (431 F 335) starts. • Screw conveyor (431 F 330) starts. • Reversing flap (431 F 325) is enabled. • Screw conveyor (431 F 320) starts • Rotary lock (431 F 315) starts. • Jet cleaning of dust collector (431 F 220) is enabled. • Fan (431 F 230) starts. • Delay of 20 seconds for fan impeller run-up. • Screw conveyor (431 F 323) starts. • Reversing flap (431 F 322) is enabled. • Automatic sampler (431 F 310) is tilting to limit switch [431 F 310-ZH]. • Rotary lock (431 F 305) starts after limit switch [431 F 310-ZH] is activated. • Drum magnet (431 F 265) starts. • Rotary lock (431 F 260) starts. • Impact flow meter (431 F 275) is enabled. • Air flow separator cage rotor (431 F 210) starts. • Throttle flap (431 F 240) closes until limit switch [431 F 240-ZL] is activated. • Delay of 20 seconds for cage rotor run-up. • Fan (431 F 245) starts, if limit switch [431 F 240-ZL] is indicating the throttle flap is closed. • Delay of 30 seconds for fan impeller run-up. • Throttle flap (431 F 240) opens until setpoint (SP 1-1 or SP 1-2 – see 3.3.3 above) is

reached. • Sub-Group 431 F 100 -Ball mill – is initiated to start

Note: Start details to be described by MBE • Sub-Group 431 F 100 completely started (ball mill 431 F 100 runs). • Screw conveyor (431 F 022) starts. • Belt weigh feeder (431 F 010) starts. • Rotary lock (431 F 055) starts if SE 4-1 is selected. • Rotary lock (431 F 355) starts. • Aeration unit (431 F 351) is enabled. • Aeration unit (431 F 051) is enabled if rotary lock (431 F 055) runs. • Group 431 F is running completely in CENTRAL mode.



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2.4.5 Restarting the Group

If the Group is in a run-empty stop sequence, (after “Normal Shut Down” (RESTOP has been initiated by the operator or the Group has been tripped after of an equipment fault) and a part of the Group is still running, it is possible to restart this Group by activating the “START” button. Restarting is only possible after all faults have been eliminated and reset. The Restart follows the same sequence like the normal Group Start including the horn sequence as described above.

2.5 Normal Operation

2.5.1 Belt Weigh Feeder 431 F 010 - • If the weigh feeder is not tripped this Group is in normal operation. • If SE 5-1 (Auto Level) is selected, the feed rate of the belt weigh feeder (431 F 010) is

automatically controlled by the electronic ear [431 F 100-LY] (ball mill material level) and by the impact flow meter [431 F 275-FY] (recycled material from the air flow classifier). The operator may select “Auto Level” at any time as long as CENTRAL operation mode is selected.

• If SE 5-2 (Auto Electronic Ear) is selected, the feed rate of the belt weigh feeder (431 F 010) is automatically controlled by the electronic ear [431 F 100-LY] (ball mill material level) only. - The operator may select “Auto Electronic Ear” at any time as long as CENTRAL operation mode is selected.

• If SE 5-3 (Auto Flow Meter) is selected, the feed rate of the belt weigh feeder (431 F 010) is automatically controlled by the impact flow meter [431 F 275-FY] (recycled material from air flow classifier) only. The operator may select “Auto Flow Meter” at any time as long as CENTRAL operation mode is selected.

• If SE 5-4 (Manual Level) has been selected the feed rate of the belt weigh feeder is set by the operator. The operator may set the feed rate at any time in a range of 1.5 to 15.0 tons/hour. Setting and display of the actual position is on SCADA. On SCADA the operator has the choice to select one of three options, “New” setpoint, “Previous” setpoint and “Standard” setpoint all overriding the actual setpoint. The operator may select “Manual Level” at any time as long as CENTRAL operation mode is selected.

2.5.2 Reversing Flap 431 F 015 • If the reversing flap is not tripped this Group is in normal operation • If the reversing flap is positioned correctly so that limit switch [431 F 015-ZH] is activated

(flow to screw conveyor 431 F 022)), this Group is in normal operation.

2.5.3 Screw Conveyor 431 F 022 • If the conveyor is not tripped this Group is in normal operation.

2.5.4 Rotary Lock 431 F 055 • If the rotary lock is not tripped this Group is in normal operation.



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• This rotary lock is equipped with a variable speed drive. The speed can be varied between 20 % and 100 % corresponding a feed rate between 0.2 and 2.0 tons/hour. If “Add Floor Dust “ (SE 2-1) is selected, this feed rate can be varied any time. On SCADA the operator has the choice to select one of three options, “New” setpoint, “Previous” setpoint and “Standard” setpoint (first approach for Standard Setpoint is 50%) all overriding the actual setpoint.

2.5.5 Reversing Flap 431 F 060 • If the reversing flap is not tripped this Group is in normal operation • If SE 4-1 – “Add Filter Dust” is selected and if the reversing flap is positioned correctly so

that limit switch [431 F 060-ZH] is activated (flow to ball mill system air circuit), this Group is in normal operation.

• If SE 4-2 – “Filter Dust Local” is selected and if the reversing flap is positioned correctly so that limit switch [431 F 060-ZL] is activated (flow to bulker bag), this Group is in normal operation.

2.5.6 Ball Mill Sub-Group 431 F 100 • If the ball mill sub-group (ball mill with all auxiliary equipment) is not tripped this Group is in

normal operation. (Details to be prepared by MBE)

2.5.7 Air Flow Classifier 431 F 210 • If the classifier is not tripped this Group is in normal operation. • The airflow classifier is equipped with a variable speed drive. Setting the speed of the

dynamic classifier can be done at any time but requires a password of a shift leader. The cage wheel speed can be varied between 20 % and 100 %. - 20 % 83 RPM - 100 % 416 RPM Note: It is critical to “play” with the cage rotor speed because this has great influence on the ball mill product grain size. On SCADA the operator has the choice to select one of three options, “New” setpoint, “Previous” setpoint and “Standard” setpoint (first approach for Standard Setpoint is 36%) all overriding the actual setpoint.

2.5.8 Dust Collector 431 F 220 • If the dust collector is not tripped this Group is in normal operation.

2.5.9 Fan 431 F 230 • If the fan is not tripped this Group is in normal operation.

2.5.10 Fan 431 F 245 • If the fan is not tripped this Group is in normal operation.


2.5.12 Drum-type Magnet 431 F 265 • If the magnet is not tripped this Group is in normal operation



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2.5.13 Impact Flow Meter 431 F 275 • If the flow meter is not tripped this Group is in normal operation

2.5.14 Reversing Flap 431 F 280 • If the reversing flap is not tripped this Group is in normal operation • If the reversing flap is positioned correctly so that limit switch [431 F 280-ZL] is activated

(flow to double pendulum flap), this Group is in normal operation.

2.5.15 Automatic Sampler 431 F 310 • If the sampler is not tripped this Group is in normal operation • If SE 3-1 - “Auto Sample” is selected on SCADA automatic sampling of the ball mill

product is enabled. Sampling is controlled by a software timer. All (SWT –see 3.3.3 above, SP 6) hours a sample is be taken. The sampling pelican is tilting from the parking position at side A to side B or vice versa, where ever the pelican sampler is actually located. If the sampling pelican does move from limit switch to limit switch [431 F 310-ZL to 431 F 310-ZH or vice versa] within a time limit of 10 seconds this Group is in normal operation.

• If SE 3-2 - “Manual Sample” is selected and the operator has initiated taking a sample and the sampling pelican moves from parking position A to B or vice versa within a time limit of 10 seconds, this Group is in normal operation.

• If SE 3-2 is selected and the operator is clicking on the “Sample” button (SE 3-3) on SCADA a single sample is taken. If the sampling pelican moves from parking position A to B or vice versa within a time limit of 10 seconds, this Group is in normal operation.

2.5.16 Reversing Flap 431 F 322 • If the reversing flap is not tripped this Group is in normal operation • If “Auto Select” SE 7-1 is selected and if the Filter Dust Bin (431 C 100) is full [431 C 100-

LAH2 is indicating very high level] and this reversing flap is adjusted at 100% material flow to screw conveyor (431 F 323) [limit switch 431 F 322-ZL is actuated], the flap tilts to limit switch [431 F 322-ZH] automatically




2.5.20 Reversing Flap 431 F 325 • If the reversing flap is not tripped this Group is in normal operation • If “Auto Select” SE 2-3 is selected and if the “Ball Mill Fraction” bin (431 F 400) is full [431

F 400-LAH2 is indicating very high level] and this reversing flap (431 F 325) is not adjusted at 100% material flow to screw conveyor (431 F 330) [limit switch 431 F 325-ZL is not actuated] and the “Fresh Adsorbent” bin (431 F 450) is not full the flap tilts to limit switch [431 F 325-ZL] automatically.



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• If “Auto Select” SE 2-3 is selected and if the “Fresh Adsorbent” bin (431 F 450) is full [431 F 450-LAH2 is indicating very high level] and this reversing flap (431 F 325) is not adjusted at 100% material flow to the “Ball Mill Fraction” bin (431 F 400) [limit switch 431 F 325-ZH is not actuated] and the “Ball Mill Fraction” bin (431 F 400) is not full the flap tilts to limit switch [431 F 325-ZL] automatically.

• If “Auto Select” SE 2-3 is selected and if the “Ball Mill Fraction” bin (431 F 400) is nearly empty [431 F 400-LAL is indicating low level – 10% of maximum level -] and this reversing flap (431 F 325) is not adjusted at 100% material flow to the “Ball Mill Fraction” bin [limit switch 431 F 325-ZH is not actuated] the flap tilts to limit switch [431 F 325-ZH] automatically.

• If “Auto Select” SE 2-3 is selected and if the “Fresh Adsorbent” bin (431 F 450) is nearly empty [431 F 450-LAL is indicating low level – 10% of maximum level -] and this reversing flap (431 F 325) is not adjusted at 100% material flow to the “Fresh Adsorbent” bin [limit switch 431 F 325-ZL is not actuated] the flap tilts to limit switch [431 F 325-ZL] automatically but only if there is no low level at the “Ball Mill fraction” bin [431 F 400-LAL] indicated.



2.5.23 Rotary Lock 431 F 355 • If the rotary lock is not tripped this Group is in normal operation. • This rotary lock is equipped with a variable speed drive. The speed can be varied between

20 % and 100 % corresponding a feed rate between 0.5 and 2.5 tons/hour. Setting and display of the actual position is on SCADA at any time. On SCADA the operator has the choice to select one of three options, “New” setpoint, “Previous” setpoint and “Standard” setpoint (first approach for Standard Setpoint is 50%) all overriding the actual setpoint.

2.5.24 Fraction Bin 431 F 400 –“Ball Mill Fraction” • If the fraction bin level measurement is not tripped this Group is in normal operation. • If “Auto Select” SE 2-3 is selected and if the fraction bin (431 F 400) is nearly empty [431 F

400-LAL is indicating low level – 10% of maximum level -] there is an alarm and the reversing flap (431 F 325) tilts to limit switch [431 F 325-ZH] automatically to refill the bin if the gate is not already adjusted at 100% material flow to the “Ball Mill Fraction” bin [limit switch 431 F 325-ZH is actuated].

• If the fraction bin is not full (bin level is not >/= 95% [431 F 400-LAH2] and/or not >/= 100% [431 F 400-LAHH]) this Group is in normal operation.

• If “Auto Select” SE 2-3 is selected and if the fraction bin is full (bin level is >/= 95% [431 F 400-LAH2] and/or >/= 100% [431 F 400-LAHH]) and the flap of reversing flap (431 F 325) is after a travel time of 90 seconds at 100% material flow to screw conveyor 431 F 330 [limit switch 431 F 325-ZL actuated] this Group is in normal operation.



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2.5.25 Fresh Adsorbent Bin 431 F 450 • If the fraction bin level measurement is not tripped this Group is in normal operation. • If “Auto Select” SE 2-3 is selected and if the bin (431 F 450) is nearly empty [431 F 450-

LAL is indicating low level – 10% of maximum level -] there is an alarm and the reversing flap (431 F 325) tilts to limit switch [431 F 325-ZL] automatically to refill the bin if the gate is not already adjusted at 100% material flow to screw conveyor (431 F 330) [limit switch 431 F 325-ZL is actuated].

• If the bin is not full (bin level is not >/= 95% [431 F 450-LAH2] and/or not >/= 100% [431 F 450-LAHH]) this Group is in normal operation.

• If “Auto Select” SE 2-3 is selected and if the bin is full (bin level is >/= 95% [431 F 450-LAH2] and/or >/= 100% [431 F 450-LAHH]) and the flap of reversing flap (431 F 325) is after a travel time of 90 seconds at 100% material flow to the “Ball Mill Feed” bin (431 F 400) [limit switch 431 F 325-ZH actuated] this Group is in normal operation.

2.5.26 Throttle Flap 431 F 240 • If the throttle flap is not tripped this Group is in normal operation. • The operator may set the flap position at any time in a range of 0% to 100% [0% = limit

switch position 431 F 240-ZL]. Setting and display of the actual position is on SCADA. On SCADA the operator has the choice to select one of three options, “New” setpoint, “Previous” setpoint and “Standard” setpoint all overriding the actual setpoint (Standard setpoint: 80% open). Note: Changing of this set point requires the shift leaders password. If the flap is closed too much the mill could overflow!

2.6 Group Shut Down

2.6.1 Normal Shut Down

To initiate this sort of shut down the operator uses the “RESTOP” button on the SCADA system.

After a shut down of the Group or of a part of the Group all actual setpoints of this Group are memorized as “Actual Setpoint”.

• The operator stops this Group using the “RESTOP” push button on SCADA. • Ball mill Sub-Group (431 F 100) stop sequence is initiated. (Details of the stop sequence

of this Sub-Group to be prepared by MBE) • Rotary lock (431 F 055) stops. • Rotary lock (431 F 355) stops. • Aeration unit (431 F 051) cycle is disabled and solenoid [431 F 051-ZY1] closes. • Aeration unit (431 F 351) cycle is disabled and solenoid [431 F 351-ZY1] closes. • Screw conveyor (431 F 022) stops. • Delay of 2 minutes (run-empty time for circulation air pipework) • Circulation fan (431 F 245) stops. • Delay of 5 minutes (run-empty time for rest of equipment)



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• All equipment of this Group stops or is disabled. Equipment perhaps in motion like the automatic sampler (431 F 310) or the reversing flap (431 F 325) is finishing the actual operation step first.

Note: MBE to add stop philosophy of Sub-Group 431 F 100.

• The whole Group is stopped.

2.6.2 Shut Down by Other Groups

If this Group 431 F is running in CENTRAL mode it requires the following other Groups also running in CENTRAL operation mode:

• 431 C – “Main Dust Treatment”


2.6.2.1 Group 431 C – Main Dust Treatment • Because a mayor part of equipment of this Group 431 F is connected to the Main Dust

Treatment it is essential that Group 431 C is running in CENTRAL control mode and is not in a START or STOP sequence.

• If Group 431 C is not running anymore in CENTRAL mode because it has been stopped by a Normal Shut Down (RESTOP), by a Fast Shut Down (FASTOP) or is tripped through a fault a Fast Shut Down (see 2.6.3 below) is initiated.

2.6.3 Fast Shut Down

If this Group 431 F is running in CENTRAL mode and an operator has detected a serious fault, which did not automatically trip this Group the operator is able to stop this Group as Fast Shut Down (FASTOP).


2.6.3.1 Fast Shut Down by the Operator (FASTOP)

The operator may initiate the Fast Shut Down of this Group at any time on the SCADA system by actuating the “FASTOP” button.

• All equipment of this Group stops instantly except of the ball mill Sub-Group 431 F 100, which stops according to the normal stop sequence as described above.

• All actual setpoints of this Group are memorized as “Actual Setpoint” • Reversing flap (431 F 325) is finishing the operating step, if this step has been started

prior to the FASTOP signal and stops, when the target position is reached. • Automatic sampler (431 F 310) is finishing the operating step, if this step has been started

prior to the FASTOP signal and stops, when the target position is reached. • The whole Group is stopped now with full load of material in conveyors.



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Rev. 00

2.6.4 Trip in Case of Faults

If this Group 431 F is running in CENTRAL mode and an equipment or an instrument of this Group fails this may cause an Alarm only and, if the fault is of the serious sort, this whole Group or a part of this Group is stopped. Different faults may cause different stop sequences, depending on the equipment and on the impact of this fault on the whole process of this Group. In some cases a Normal Shut Down (RESTOP) will commence, in other cases a Fast Shut Down (FASTOP) is the safer way and in few cases a special stop sequence may be required.


Note: All instruments mounted on equipment or located somewhere in the field or anywhere else are to be wired fail-safe.

2.6.4.1 Belt Weighfeeder 431 F 010

A collective fault signal

- causes an alarm - drive stops - This is causing a Normal Shut Down as described above (see 2.6.1).

2.6.4.2 Reversing Flap 431 F 015

[431 F 105-ZH] If the limit switch fails

- causes an alarm - Normal Shut Down as described above (see 2.6.1).

2.6.4.3 Screw Conveyor 431 F 022

[431 F 022-SAL] The screw conveyor is equipped with a proximity type low-speed detector measuring the frequency of a target rotating with the screw. If the frequency of the screw is too low or the switch fails

- cause an alarm - equipment trips

[431 F 022–M1] If there is a fault detected in the electric motor or in the MCC of this motor


If the conveyor trips

- alarm is generated - Normal Shut Down as described above (see 2.6.1).

2.6.4.4 Rotary Lock 431 F 055

[431 F 055-SAL] The rotary lock is equipped with a proximity type low-speed detector measuring the frequency of a target rotating with the rotor. If the frequency of the rotor is too low or the switch fails

- cause an alarm



20 (28)


Rev. 00

- equipment trips [431 F 055–M1] If there is a fault detected in the electric motor or in the MCC of this motor


If the rotary lock trips

- alarm is generated.

2.6.4.5 Ball Mill Sub-Group 431 F 100

MBE to describe all faults of this Sub-Group.

If the Sub-Group trips

- alarm is generated - Normal Shut Down (see 2.6.1 above) of this Group 431 F is executed.

2.6.4.6 Air Flow Classifier 431 F 210

[431 F 210-SAL] {50 1/min} The airflow classifier is equipped with a low speed switch, which gives a trip signal if the speed is below the minimum setting. If the speed is too low or the switch fails

- cause an alarm - shut down of this equipment.

[431 F 210-TAHH1/TAHH2] {>90°C} The airflow classifier is equipped with 2 bearing temperature measurements. If one of the bearing temperatures is too high or the measuring equipment fails


If there is a failure detected in the motor control system


If the equipment trips

- alarm is generated - Normal Shut Down (see 2.6.1 above) of this Group 431 F is executed.

2.6.4.7 Dust Collector 431 F 220

[431 F 220-LOP1] If the bag cleaning device trips

- an alarm is generated - Normal Shut Down (see 2.6.1 above) will be initiated automatically.

[431 F 220-PDAL] {< 2.5mbar} If low differential pressure is detected across the filter bags or if the switch fails for more than 5 seconds

- cause an alarm followed



21 (28)


Rev. 00

- Fast Shut Down of this Group (see 2.6.3 above), which is initiated automatically. NOTE: During Start or Restart of this Group there is an override of this function of 20 seconds to allow the fan to run up.

[431 F 220-PDAH] {> 13mbar} If high differential pressure is detected across the filter bags or if the switch fails for more than 5 seconds

- cause an alarm

[431 F 220-PDAHH] {> 15mbar} If high-high differential pressure is detected across the filter bags or if the switch fails for more than 5 seconds

- cause an alarm - Normal Shut Down of this Group (see 2.6.1 above), which is initiated automatically.

2.6.4.8 Fan 431 F 230 [431 F 230–M1] If there is a fault detected in the electric motor or in the MCC of this motor

- cause an alarm - equipment trips.

[431 F 230-SAL] The fan is equipped with a proximity type low-speed switch measuring the frequency of a target rotating with the impeller shaft. If the frequency of the rotor is too low or the switch fails

- cause an alarm followed - equipment trips

If the fan trips

- an alarm is generated - fan (431 F 230) is shut down instantly - cause an alarm - Fast Shut Down of this Group (see 2.6.3 above), which is initiated automatically.

2.6.4.9 Throttle Flap with Servo Drive 431 F 240

[431 F 240-ZL / ZH] The throttle flap is equipped with two limit switches, incorporated in a control box fitted to the drive unit. If a limit switch fails

- causes an alarm - equipment trips

[431 F 240-XAL / XAH] The throttle flap is equipped with two torque switches, incorporated in a control box fitted to the drive unit. If a switch is actuated or a electric motor: [431 F 240–M1] If there is a fault detected in the motor or in the MCC of this motor


The maximum time required between start and stop of the actuator drive, which is tilting the throttle of the throttle flap, shall not be more than 90 seconds. If after 90 seconds the motor has not been stopped automatically because the target position has not been reached

- cause an alarm - equipment trips.



22 (28)


Rev. 00

If the throttle flap trips

- alarm is generated - flap (431 F 240) is shut down instantly - This will cause an alarm - Fast Shut Down of this Group (see 2.6.3 above), which is initiated automatically.

2.6.4.10 Fan 431 F 245 –Circulation Fan -


- cause an - equipment trips

[431 F 245-SAL] The fan is equipped with a proximity type low-speed switch measuring the frequency of a target rotating with the impeller shaft. If the frequency of the rotor is too low or the switch fails


[431 F 245-VAH] The fan is equipped with a vibration switch. If vibration is too high

- fan trips

If the fan trips

- alarm is generated - fan (431 F 245) is shut down instantly - This will cause an - Fast Shut Down of this Group (see 2.6.3 above), which is initiated automatically.

2.6.4.11 Rotary Lock 431 F 260






- alarm is generated - Fast Shut Down of this Group (see 2.6.3 above), which is initiated automatically.

2.6.4.12 Drum-Type Magnetic Separator 431 F 265

[431 F 265-M1] If there is a fault detected in the electric motor or in the MCC of the motor




23 (28)


Rev. 00

[431 F 265-SAL] The magnetic separator is equipped with a proximity type low-speed detector measuring the frequency of a target rotating with the magnetic drum. If the frequency of the drum is too low or the switch fails


If the magnet drive trips

- alarm is generated - Fast Shut Down (see 2.6.3 above) of this Group 431 F is executed.

2.6.4.13 Impact Flow Meter 431 F 275

A collective fault signal is causing an alarm and disables the flow meter.

• If SE 5-1 (“Auto Level”) is selected - causing Normal Shut Down as described above (see 2.6.1).

• If SE 5-3 (“Auto Flow Meter”) is selected - causing a Normal Shut Down as described above (see 2.6.1).

2.6.4.14 Reversing Flap 431 F 280

[431 F 280-ZH] The reversing flap is equipped with a limit switch. If the limit switch fails

- causes an alarm - Fast Shut Down as described above (see 2.6.3).

2.6.4.15 Rotary Lock 431 F 305







2.6.4.16 Automatic Sampler 431 F 310 – pneumatic -

[431 F 310-ZH / ZL] The sampler is equipped with two proximity type limit switches. If one of the switches fails




24 (28)


Rev. 00

The maximum time required by the pneumatic drive for tilting the pelican type sampler from one limit switch to the other one shall not be more than 10 seconds. If after 10 seconds the limit switch is not reached


If the sampler trips


2.6.4.17 Rotary Lock 431 F 315








[431 F 320-SAL] The screw conveyor is equipped with a proximity type low-speed detector measuring the frequency of a target rotating with the screw. If the frequency of the screw is too low or the switch fails this


[431 F 320–M1] If there is a fault detected in the electric motor or in the MCC of this motor - cause an alarm - equipment trips



2.6.4.19 Reversing Flap 431 F 325 – pneumatic -

[431 F 325-ZH / ZL] The flap is equipped with two proximity type limit switches. If one of the switches fails

- causing an alarm - equipment trips



25 (28)


Rev. 00

The maximum time required by the pneumatic drive for tilting the reversing blade from one limit switch to the other one shall not be more than 10 seconds. If after 10 seconds the limit switch is not reached

- causing an alarm - equipment trips

If the flap trips





[431 F 330–M1] If there is a fault detected in the motor or in the MCC of this electric motor



- alarm is generated - if the reversing flap (431 F 325) is positioned to feed this screw conveyor [limit switch

431 F 325-ZL is activated] a Fast Shut Down for this Group (see 3.5.3 above) is initiated automatically.







- alarm is generated - if the reversing flap (431 F 325) is positioned to feed the screw conveyor (431 F 330)

[limit switch 431 F 325-ZL is activated] a Fast Shut Down for this Group (see 3.5.3 above) is initiated automatically.



26 (28)


Rev. 00

2.6.4.22 Ball Mill Fraction” Bin 431 F 400

[431 F 400-LY] The bin is equipped with a continuous level measurement (load cell system). If the level measurement fails

- cause an alarm - if the reversing flap (431 F 325) is not in position [limit switch 431 F 325-ZL is not

activated] to feed the screw conveyor (431 F 330) a Normal Shut Down of this Group (see 2.6.1 above) is initiated automatically.

[431 F 400-LAHH] The bin is equipped with a level probe. If the level measurement fails

- cause an alarm - if the reversing flap (431 F 325) is not in position [limit switch 431 F 325-ZL is not

activated] to feed the screw conveyor (431 F 330) a Fast Shut Down of this Group (see 2.6.3 above) is initiated automatically.

2.6.4.23 ”Fresh Adsorbent Bin 431 F 450

[431 F 450-LY] The bin is equipped with a continuous level measurement (load cell system). If the level measurement fails

- cause an alarm - if the reversing flap (431 F 325) is not in position [limit switch 431 F 325-ZH is not

activated] to feed the Ball Mill Feed bin (431 F 400) a Normal Shut Down of this Group (see 2.6.1 above) is initiated automatically.

[431 F 450-LAHH] The bin is equipped with a level probe. If the level measurement fails

- cause an alarm - if the reversing flap (431 F 325) is not in position [limit switch 431 F 325-ZH is not

activated] to feed the Ball Mill Fraction bin (431 F 400) a Fast Shut Down of this Group (see 3.5.3 above) is initiated automatically.

2.6.5 Shut Down by Full Bins

2.6.5.1 “Ball Mill Fraction” Bin 431 F 400

If “Auto Select” SE 2-3 is selected and if the fraction bin is full (bin level is >/= 95% [431 F 400-LAH2]) and the flap of reversing flap (431 F 325) is not after a travel time of 90 seconds at 100% material flow to screw conveyor (431 F 330) [limit switch 431 F 325-ZL is not actuated]

- Normal Shut Down of this Group (see 2.6.1 above) is initiated automatically.

If “Manual Select” SE 2-4 is selected and if the fraction bin is full (bin level is >/= 95% [431 F 400-LAH2]) and the flap of reversing flap (431 F 325) is not at 100% material flow to screw conveyor (431 F 330) [limit switch 431 F 325-ZL is not actuated]


If the fraction bin is totally full (bin level >/= 100% [431 F 400-LAHH]) and the flap of reversing flap (431 F 325) is not at 100% material flow to screw conveyor (431 F 330) [limit switch 431 F 325-ZL actuated]

- Fast Shut Down of this Group (see 2.6.3 above) is initiated automatically.



27 (28)


Rev. 00

If the fraction bin is full (bin level is >/= 95% [431 F 400-LAH2]) and if the Fresh Adsorbent bin (431 F 450) is also full (bin level is >/= 95% [431 F 450-LAH2 and/or bin level >/= 100% [431 F 450-LAHH])


2.6.5.2 “Fresh Adsorbent” Bin 431 F 450

If “Auto Select” SE 2-3 is selected and if the bin is full (bin level is >/= 95% [431 F 450-LAH2]) and the flap of reversing flap (431 F 325) is not after a travel time of 90 seconds at 100% material flow to the Ball Mill Feed bin (431 F 400) [limit switch 431 F 325-ZH is not actuated]


If “Manual Select” SE 2-4 is selected and if the bin is full (bin level is >/= 95% [431 F 450-LAH2]) and the flap of reversing flap (431 F 325) is not at 100% material flow to the Ball Mill Feed bin (431 F 400) [limit switch 431 F 325-ZH is not actuated]


If the bin is totally full (bin level >/= 100% [431 F 450-LAHH]) and the flap of reversing flap (431 F 325) is not at 100% material flow to the Ball Mill Feed bin (431 F 330) [limit switch 431 F 325-ZH is not actuated]

- Fast Shut Down of this Group (see 2.6.3 above) is initiated automatically.

If the bin is full (bin level is >/= 95% [431 F 450-LAH2]) and if the Ball Mill Feed bin (431 F 400) is also full (bin level is >/= 95% [431 F 400-LAH2 and/or bin level >/= 100% [431 F 400-LAHH])


2.7 Local Operation of Special Equipment

2.7.1 Ball Mill Sub-Group 431 F 100

Local operation of the ball mill requires the lubrication units, jack pumps, grease spry unit, inching drive to start and stop in certain sequence.

Note: This sequence has to be described by MBE.



28 (28)


Rev. 00


2.8 Signal Exchange with Sub-Groups of this Group and Other Process Groups

Signal Description Sort of Signal from Group 431 C to Group 431 F

Group 431 C is running in CENTRAL mode and is not in any Group START or STOP sequence

Digital signal within PLC Number 431 PLC 12

from Group 431 C to Group 431 F

Floor Dust Bin is indicating very high level [431 C 100-LAH2]


from Medium Voltage Substation to Group 431 F

6.6 kV available by VEDANTA

from Group 431 F to Group 431 F 100

Start Sub-Group 431 F Digital signal within PLC Number 431 PLC 12


Stop Sub-Group 431 F Digital signal within PLC Number 431 PLC 12

from Sub-Group 431 F 100 to Group 431 F

Sub-Group 431 F 100 is running in CENTRAL mode and is not in any Group START or STOP sequence and is not tripped



Sub-Group 431 F 100 is ready to be started



Sub-Group 431 F 100 is completely shut down



Further signals to be described by MBE



Further signals to be described by MBE



138-02-043 Group 431/432 F

DE-060300


13.3 Main Equipment

13.3.1 Belt Weigh Feeder 431/432 F 010

13.3.2 Double Pendulum Flap 431/432 F 025

13.3.3 Ball Mill 431/432 F 100

13.3.4 Dynamic Classifier 431/432 F 210

13.3.5 Cyclone 431/432 F 215

13.3.6 Throttle Flap (motorized) 431/432 F 240

13.3.7 Circulation Fan 431/432 F 245

13.3.8 Drum-Type Magnetic Separator 431/432 F 265

13.3.9 Impact Flow Meter 431/432 F 275

13.3.10 Automatic Sampler (pneumatic) 431/432 F 310

431f-432f

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