new idea for crushersdesign in cement factories -...

IPASJ International Journal of Mechanical Engineering (IIJME) Web Site: http://www.ipasj.org/IIJME/IIJME.htm

A Publisher for Research Motivation........ Email: [email protected] Volume 3, Issue 9, September 2015 ISSN 2321-6441

Volume 3, Issue 9, September 2015

ABSTRACT The present work a new design idea of a crusher to be used in the cement factory in consistence with the existed working conditions; the new design is named a hybrid crusher. This crusher consists of the three cylindrical rollers; they are used for reducing stone to small size by three stages, working as a primary, secondary and fine crusher. This is beneficial due to the reduced primary cost, lower power consumption, reduced working time, decrease of maintenance and avoiding transportation of material from primary crusher to secondary crusher machine. Using this hybrid crusher leads to increase the production per hour and high reduction ratio more than all types of crusher, and it is a highly simple machine and easy to change all its parts. For this design, the calculations were conducted for all items used in this machine, and detailed drawings for all items were prepared in addition to 3D modeling picture and 3D animation for presentation. Keywords: crusher design, hammer, impact, cement factory.

1. INTRODUTION The fundamental goal for the design of a crushing plant is an installation that meets the required production requirements, operates at competitive cost, complies with today’s tough environmental regulations, and can be built at a reasonable price despite the rising costs of equipment, energy and construction labor [1]. The choice of crusher depends on the type and amount of material to be crushed. Gyratory and jaw crushers represent the bulk of primary crushers used at mining operations today, although some operations use roll impact crushers, low-speed roll sizes and feeder breakers. Cone crushers remain the most popular for fine crushing applications, although some mines use vertical impact crushers for tertiary and quaternary crushing. A well-designed plant layout balances the capital versus operating cost over mine life. Buildings, infrastructure, and major equipment items, represent the major cost elements of a crushing plant. The designer must prepare a layout that suits the design criteria, flow sheet and selected equipment in the most economical possibleconfiguration. It’s important to keep structural costs down, to design for ease of maintenance and operation, and to combine best practices with advances in fabrication and erection. Input from an experienced mining plant structural engineer can be very helpful [2]. 2. CRUSHER The second step in making cement begins with crushing of limestone as mined and received. In turn, the crushing operation prepares stone for the subsequent operation of grinding or pulverizing. The extent of size reduction in crushing operation depends on one hand on the (run off mine) stone as received from quarries and the size of stone as required by the mills selected for grinding. On the other hand, the size of (run off mine) stone depends on whether mining is (manual) or (mechanized), manual mining is relevant only to small plants. Mined stone pieces are carried as head loads, and the size is limited to - 300 mm. Mechanized mining uses shovels and dumpers for bringing stone to crusher. Ball mills for grinding size of feed require generally less than 25 mm, the smaller is the better. Vertical Roller Mills, Roller Presses and Horizontal Mills can receive stone between 75 to 100 mm sizes. [3,4]. 2.1 Type of Crushers Main types of crushers used in Cement Industry to crush limestone are: 2.1.1 Jaw Crusher One of the most popular stone-crushing equipment in the world, Jaw Crusher is ideally suitable for primary and secondary crushing. The highest anti-pressure strength of crushed material is 320 MPa. Our design and production are of high position both at home and abroad. One of our main products, Jaw Crusher is designed by our engineers with large reduction ratio, even granularity, simple structure, reliable operation, convenient maintenance, low cost. It is widely used in mining, metallurgy, construction, highway, railroad, and chemical industries [5]. Fig.1 shows jaw crusher [6].

New Idea for CrushersDesign in Cement Factories

Dr.Jassim M. A. Jaff1, Hallow K. Rauf2, Mastan H. Hama Sallih3

Sulaimani Polytechnic University- College of Technical Engineering- Sulaimani – IRAQ




2.1.2 Hammer Crusher As the name suggests rotating hammers mounted on discs pound the stone fed into the crusher against breaking plates. Stone is broken into smaller pieces and gets further reduced because of reducing clearance between tips of hammers and breaking plates. The bottom is fitted with grate bars fully or partially through which stone crushed smaller than the spacing in the grate, passes. Over size is subject to repeated pounding till it is finished to size [7,8]. Fig.2 shows hammer crusher [8].

2.1.3 Impact Crusher

Dealing with the material with the side length of 500 mm, not more than 350 MPa anti-pressure strength, the Impact Crusher can be widely used in the first and secondary crushing. During the process of operating, the rotor in high speed will be brought along by the electric motor. The material will be stricken by the Flat Hammer to be crushed, then be countered to the liner for the second crushing, and then be discharged through the discharge opening [9,10].Impact Crusher features many advantages: simple structure, high chromium Flat Hammer, special impact plate, simplified crushing process, and high-efficiency and energy conservation, Cubic Shape for the final products, expressway, sand and stone, crushing fields are the main products. Fig.3 shows impact crusher.

Figure 1 Jaw Crusher [6].

Figure 2 Hammer Crusher [8].

Figure 3Impact Crusher [9].




2.1.4 Cone Crusher

Cone crusher is widely applied in metallurgical, construction, road building and chemical and phosphate industry. This crusher is suitable for hard and mid hard rocks and ores, such as iron ores, copper ores, limestone, quartz, granite, grit stone, etc. Type of the crushing cavity is decided by the application of the ores [11,12].Fig.4 shows Conecrusher.

3. PROCEDURES DESIGN OF HYBRID CRUSHER This crusher is designed as basic of (hybrid crusher) due to combine (crusher machine and milling machine) together and worked as three principle working ideas, when every idea is worked as an individual machine working by three various types of roller. The first roller is designed as a stocking limestone and is powerful for stocking limestone from (1 m3 to 0.35 m3) [12]. The second roller is designed as a crushing roller and is powerful for crushing limestone from (0.35 m3 to 0.1 m3) and the other roller is designed as a milling roller for milling limestone and is powerful for milling limestone from (0.1 m3 to 0.02 m3), as shown in fig.5. The objective of this idea is beneficial to (reduce primary cost, lower power consumption, reduce of working time, decrease of maintenance and avoid transportation of material from crusher machine to milling machine) and to (increase production per hour and high reduction ratio more than all types of crusher. It is a very highly simple machine and easy to change all its part), as shown in fig.5. Hybrid crusher is designed as a simple machine due to the ability of changing every part when is needed and easy for maintenance and inspection, it consists of the following parts:

3.1 Machine Frame It is the most importance part of the crusher, and the design of machine frame is the heart of crusher design due to the ability of designing with less material consumption used by form design or modeling design which are optimized to avoid the dead area and volume. This causes a decrease in (material, weight and cost) and must be designed to easy

Figure4 Cone crusher [11].

Figure5 3D Hybrid crusher modeling




assembling and transportation. The selection of machine frame material is most important due to the need for impact resistance, wear and corrosion resistance, improved machine-ability and weld-ability, less weight, and avoid vibration. For this purpose, alloy steels are used, and the machine frame is divided into three following parts: 3.1.1 Machine base It is the very rigid body of the machine frame, the two other parts of machine frame supported on the machine base by a hinge are opened and closed by a hydraulic jack, and the machine base is holding the three rollers by a holder on the other side. 3.1.2 Right side machine frame It is the part of machine frame where the entrance of crusher machine is content with limestone and other types of stone which are input to the machine through the right side machine frame. Also, it is supported on the machine base by a hinge, opened by a hydraulic jack when the maintenance of machine roller or internal machine parts is needed and has one door to inspection of hammering roller. 3.1.3 Left side machine frame The part of machine frame is included on left side of machine, supported on the machine base by a hinge, opened by a hydraulic jack when the maintenance of machine roller or internal machine parts is needed and has three doors to inspection of milling roller and cleaning the internal of machine from clay and dust, as shown in fig.6.

3.2 Hybrid Crusher Machine Roller The principle idea of crushing work is included, the most important parameter of crusher design, it must be also designed as very simple, easy to change every item and rigid. The angle between the roller and sliding guide-way and the distance between them are very importance to reduction of limestone, and the ratio of size roller to size of limestone is called gold ratio. Crusher machine roller consists of the following three rollers (hammering roller, crushing roller and milling roller) when all rollers are rotated at 180 R.P.M, as shown in fig.7.

Figure6 hybrid crusher main frame and hydraulic system specification

Figure7hybrid crusher machine roller specification




3.2.1 Hammering Roller The first roller of crusher machine that works as a hammer, is therefore named as a hammering roller, it has the ability to stroking limestone from (1 m3) to some little part approximately to (0.3 m3 to 0.2 m3). The system consists of several items combined together; the main frame roller with shaft is cast together and is made of steel 50:11. The shape of hammer is more important to ability for breaking stone and selection of material to resist impact strength and wear. Six hammers are usually made of alloy steel. Six attachments to lock the hammer through twenty four bolts are benefit for locking hammer, they must not open when rotating and working.

Two taper roller bearings are very suitable for resisting the high radial load with longer life than other bearings used for holding the hammering roller on the other side. One pulley is connected by a motor through a V-belt used for rotating the hammering roller, as shown in figures (8,9). 3.2.2 Crushing Roller The second roller of crusher machine that works as a crusher, is therefore called a crushing roller, it has the ability to crushing limestone from (0.35 m3 to 0.2 m3) to some little part approximately to (0.1 m3 to 0.05 m3). The system consists of several items combined together; the main frame roller with shaft is cast together and is made of steel 50:11. The shape of crushing block is more important to ability for crushing stone and selection of material to resist impact strength and wear. Twelve crushing block are usually made of alloy steel. Eight attachments to lock the crushing block through sixteen bolts are benefit for locking crushing block; they must not open when rotating. Two taper roller bearings and one pulley are very suitable for the holder, as depicted in figures (10,11).

Figure 8Hammering roller 3D modeling.

Figure 9 Hammering roller parts detail drawing.

Figure 10 Crushing roller 3D modeling.




3.2.3 Milling Roller

This is the third roller of crusher machine that works as a milling, is therefore named a milling roller, it has the ability to milling limestone from (0.1 m3 to 0.05 m3) to some little part approximately to (0.02 m3 and less than 0.02 m3). The system consists of several items combined together; the main frame roller with shaft is cast together and is made of steel 50:11. The shape of milling block is more important to ability for milling stone and selection of material to resist impact strength and wear. Twelve milling blocks are usually made of alloy steel. Eight attachments to lock the milling block through sixteen bolts are benefit for locking the milling block; they must not open when rotating. Two taper roller bearings and one pulley are benefit for the holder, as show in figures (12,13).

Figure11 Crushing roller parts detail drawing.

Figure12 Milling roller 3D modeling.

Figure13 Milling roller parts detail drawing.




3.3 Hybrid Crusher Sliding Guide Way

It is the part of the crusher when limestone is sliding on it from the input of limestone to output product. It consists of two parts, the parts of left side which are moving by angle come back through the weight of limestone if the size of limestone is too large to increase crushing area, and the ware dose not jam produced. After breaking the limestone, this guide comes to front by a hydraulic system, and it is supported and connected by a hinge to other parts which are fixed along the machine. There have some profile blocks designed to complete the work of rollers, which can be easily changed when causing wear, they are made of a resistant material to impact and compression strength and wear, as shown in fig.14. 3.4 Hydraulic System 1.Hydraulic jack is used for lifting the right side and left side machine frame, it requires more capacity because of the higher load applied on it, and it is benefit to lifting the machine frame to maintenance. 2. Hydraulic damping is used for moving the left side sliding guide way when limestone is input to the machine, the sliding guide way moves back to avoid the jamming and after breaking the limestone, the sliding guide way moves to front by a hydraulic damping, as manifested in fig.6.

4.THEORETICAL AND RESULTS The principle work of crasher is the rotation of roller by using a motor and transmitting the torque from the motor to every roller through the belt by using pulley, and this crusher needs a motor when the capacity of motor is equal to 560 KW. Every roller is rotated by 180 R.P.M and the torque of motor can be determined by the power (P) of motor and speed (N) from Table 1 [13].

To convert the torque of motor (Tm) to torque of pulley (T) of roller, assume the torque of pulley is three times greater than the torque of motor, and the torque (T) of every roller is equal because every pulley is rotating as the same speed.

To determine the force of the pulley (F1) and (F2) caused by tension of belt on the pulley through using the diameter of pulley d=0.9 m and torque of roller T = 89123.76 N.m by equation:

And, assuming the ratio of forces,

Figure14 crusher sliding guide way view




Table 1: Table of data requirement[13]. NO SPECIFICATION SYMBOL QUANTITY UNIT 1 POWER OF MOTOR P 560 KW 2 SPEED N 180 R.P.M 3 TORSIONAL STRENGTH FOR STEEL 50:11 Τ 500 KGF/CM2 4 ULTIMATE CRUSHING STRENGTH FOR LIMESTONE Σ 250 MPA 5 SPEED FACTOR FN 0.53 ....... 6 TEMPERATURE FACTOR FT 1 ....... 7 LOAD CAPACITY OF TAPPER ROLLER BEARING D=420MM , D=620MM C 4200 KN 8 LOAD CAPACITY OF TAPPER ROLLER BEARING D=320MM , D=440MM C 1880 KN 9 LOAD CAPACITY OF TAPPER ROLLER BEARING D=380MM , D=520MM C 2550 KN

10 BEARING STRESS OF STEEL 50:11 ΣB 600 KGF/CM2 11 FACTOR OF SAFETY FOR COMPRESSION STRESS FS 4 - 12 FACTOR OF SAFETY FOR SHEAR STRESS FS 2 -

4.1 Diameter of Hammering Roller Shaft The shaft of hammering roller is subjected to combined stresses due to the application of bending strength (σ) and torsional strength (τ), one can determine the diameter of this shaft, and this will need to find the maximum bending moment (mb) by vertical plane, horizontal plane, torque (T) and torsional strength τ=500 kgf/cm2. Vertical Plane: By using equation:

To find the hammering force, (Fh) applied on the shaft can be determined by the ultimate crushing strength (σ=250 MPa) for limestone from table (2) and area of hammer (A=20 cm) when contact to limestone is caused to crushing

The maximum bending moment is (251753 N.m) in vertical plane from fig.15. Horizontal Plane: By using equation:

The maximum bending moment is (616170.95 N.m) in horizontal plane from fig.16.

By equation (11), [13]:

The determined diameter of the hammering roller shaft is equal to (Dh= 0.42 m).

Figure 15 Vertical shear force and bending moment diagram for hammering roller

Figure16 Horizontal shear force and bending moment diagram for hammering roller




4.2 Thickness of Hammering Roller The thickness of hammering roller is found through two ways, they are (compression stress on hammer and shear stress on hammer). To find the allowable stress, we need the bearing stress from Table 1, number of main frame hammering roller (k=7) and length of frame (L=15 cm), these are used to find the maximum thickness: 1- To find the allowable compression stress (σall), the ultimate bearing stress (σb) is used and divided by safety factor (fs = 4) by equation [13]:

2- To find the allowable shear stress (τall), the allowable compression stress (σall) is used and divided by safety factor (fs = 2) by equation:

4.3 Life of Bearing for Hammering Roller The use of taper roller bearing in hammering roller: To find the life of bearing, the ideal load (P) by radial factor (X), thrust factor (Y), radial load (Pr) and thrust load (Pa) must be determined [13]: 1. To find life of bearing (B). Result load of bearing:

Where P = Pr , X=1 , P =X. Pr

To find life of bearing (B) use ideal load (P), speed factor (Fn=0.53), temperature factor (Ft=1), and load capacity of bearing (C=4200KN) from Table 1.

Lh=60000h 2.To find life of bearing (D). Result load of bearing:

Where P = Pr , X=1 , P =X. Pr To find the life of bearing (D), use the ideal load (P), speed factor (Fn = 0.53), temperature factor (Ft = 1) and load capacity of bearing (C= 4200 KN) from Table 1.

4.4 Diameter of Crushing Roller Shaft

The shaft shaft of crushing roller is subjected to combined stresses, bending strength (σ) and torsional strength (τ). One can determine the diameter of this shaft, and this will require to find the maximum bending moment (mb) by vertical plane, horizontal plane, torque (T) and torsional strength τ = 500 kgf/cm2. Vertical Plane:By using equation:

To find the crushing force, (Fc) is applied on the shaft can be determine by the ultimate crushing strength (σ = 250 MPa) for limestone from Table 1and area of hammer (A = 20cm) when contact to limestone is caused to crushing by .

The maximum bending moment is (272293.48 Nm) in vertical plane from fig. 17. Horizontal Plane:By using equation:

The maximum bending moment is (116260.9 Nm) in horizontal plane from fig. 18.




By using equation:

The determined diameter of the crushing roller shaft is equal to (Dc = 0.32 m).

5. Thickness of Crushing Roller The thickness of crushing roller is found through two ways, they are (compression stress on crusher and shear stress on crusher). To find the allowable stress, we need the bearing stress from Table 1, number of main frame crushing roller (k=7) and length of frame (L=20cm), these are used to find the maximum thickness: 1- To find the allowable compression stress (σall), the ultimate bearing stress (σb) is used and divided by safety factor ( fs = 4) by equation:

2- To find the allowable shear stress (τall), the allowable compression stress (σall) is used and divided by safety factor (fs = 2) by equation:

4.5 Life of Bearing for Crushing Roller The use of taper roller bearing in crushingroller: To find the life of bearing, the ideal load (P) by radial factor (X), thrust factor(Y), radial load (Pr) and thrust load (Pa) must be determined: 1.To find life of bearing (B) Result load of bearing:

To find the life of bearing (B), use the ideal load (P), speed factor (Fn = 0.53), temperature factor (Ft = 1) and load capacity of bearing (C=1880 KN) from Table 1.

2. To find life of bearing (D). Result load of bearing:

Figure17 Vertical shear force and bending moment diagram for crusher roller

Figure18 Horizontal shear force and bending moment diagram for crusher roller




To find the life of bearing (D), use the ideal load (P), speed factor (Fn=0.53), temperature factor (Ft = 1), and load capacity of bearing (C=1880 KN) from Table 1.

4.6 Diameter of Milling Roller Shaft The shaft of milling roller is subjected to combines stresses, bending strength (σ) and torsional strength (τ). One can determine the diameter of this shaft, and this will need to find the maximum bending moment (mb) by vertical plane, horizontal plane, using torque (T) and torsional strength τ=500 kgf/cm2

Vertical Plane:By using equation:

To find the milling force, (Fm) is applied on the shaft can be determine by the ultimate crushing strength (σ = 250 MPa) for limestone from Table 1and area of hammer (A = 15 cm) when contact to limestone is caused to crushing by .

Maximum bending moment is (439685.36 Nm) in vertical plane from fig.19. Horizontal Plane:By using equation:

The Maximum bending moment is (199357.76 N.m) in horizontal plane from fig.20.

The determined diameter of the milling roller shaft equal to (Dm=0.38 m).

Figure19 Vertical shear force and bending moment diagram for millingroller

Figure20 Horizontal shear force and bending moment diagram for milling roller




8. Thickness of Milling Roller The thickness of milling roller ia found through two ways, they are (compression stress on milling and shear stress on milling). To find the allowable stress, we need the bearing stress from Table 1, number of main frame milling roller (k = 7) and length of frame (L = 20 cm), these are used to find the maximum thickness: 1- To find allowable compression stress (σall), ultimate bearing stress (σb) is used and divided by safety factor (fs = 4) by equation:

2- To find allowable shear stress (τall), allowable compression stress (σall) is used and divided by safety factor (fs = 2) by equation:

4.7 Life of Bearing for Milling Roller The use of taper roller bearing in milling roller: To find the life of bearing, the ideal load (P), by radial factor (X), thrust factor (Y), radial load (Pr) and thrust load(Pa) must be determined: 1.To find life of bearing (B). Result load of bearing

To find life of bearing (B), use the ideal load (P), speed factor (Fn = 0.53), temperature factor (Ft = 1), and load capacity of bearing (C=2550 KN) from Table 1.

2.To find life of bearing (D). Result load of bearing

Figures (21, 22,and 23) show the front, top, left, and right view of the detailed drawing for hybrid crusher design. From figures (24,25, and 26) as shown, the results of maximum reduction ratio of limestone of hybrid crusher are compared with the other types of crusher.




Figure24 Highest anti pressure strength of crusher material of hybrid crusher compare with other crusher




Figure25 Maximum reduction ratio of limestone of hybrid crusher compare with other crusher

Figure26 Maximum reduction ratio of limestone of hybrid crusher compare with other crusher

5. CONCLUSION 1- Hybrid crusher can be used as primary and secondary crushing and fine crushing machine, due to lower time of crusher presses. 2- It offers higher efficiency and higher reduction ratio than other crushers. 3- Hybrid crusher can be used as crushing and milling machine together. 4- It can be used for both stationary and mobile crusher processes. 5- It has a very simple machine structure, can be easily cleaned, and every item is easily maintained and changed. 6- Lower noise and very little dust are produced. 7- Hybrid crusher is ideal for crushing (Limestone, Clean Coal and Coal with Rock, Gypsum, Coke, Salt, Shale, Ores, Clay and Oil Shale).

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Table 2: of results

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new idea for crushersdesign in cement factories -...

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