typical feed water heater isolation system. -...

Preheater Protection ValvesType AVS 4/5

Tyco reserves the right to change the contents without notice SEMDR-0008-EN-0202

Typical Feed Water Heater Isolation System.

Features and BenefitsThese valves are designed to bypass highpressure feedwater around a group ofheaters in the event of high water level inthe shell caused by a defective tube, weldor drain system. The time available to giveprotection to a turbine in modern feedsystems is short but these valves canoperate in approximately 5 seconds in a300mm bore pipe system with theminimum of hydraulic shock. Protection isachieved in the system by installing fastclosing tee and changeover valves in thepipework around a heater or group ofheaters. These valves are equallyapplicable in new or established stations.The motive power employed is thefeedwater pressure and the system isdesigned to 'fail safe' in that the heaterswill be by-passed if either electric orpneumatic supplies fail.

Technical dataSizes : DN 80 - DN 500Construction : DIN 3840Pressure Class : PN 160 - PN 500


Tyco reserves the right to change the contents without notice page 2

Operation

In case of damage happening to the preheater pipes, the feedwater supplyupstream of the pump and the feed-water backflow from the boiler to thepreheater must be shut off in the shortest possible time. Quick shut off anddeviation of the flow will both prevent the preheater steam jacket designed forlow pressures from being endangered, and also maintain the feed-water supplyto the boiler. Moreover, the turbine is protected against water breaking in by flowbacks through the bleeder pipe. Due to the automatic shut off of the preheater and the simultaneous opening ofthe by-pass line, the feed-water keeps on flowing steadily. Even excessive pipelenghts between the pump and the AV5 valve will not create any additionaldynamic forces. Due to the deviation of flow, the water column contained in theby-pass will have to be accelerated. Short by-pass pipes will keep suchacceleration forces on a low level. The AV quick closing valves are controlled by their own medium and willrespond within a second's time, without varying operating forces and almostfree of friction, because the valve seating faces close axially and do not slide oneach other, as e.g. with gate valves.If the feed-water pressure within the preheater pipes rises due to faulty controlor during trial runs, the AV valves will act as safety valves and open slightly.In normal operation pump pressure will prevail in the inlet of the AV5 changeovervalve. Due to pressure losses, the pressure in the by-pass line is somewhatlower. This pressure differential as well as the balanced stem that is passed tothe outside, will safely hold the disc of the AV valve in open position, providing ashut off towards the by-pass. Minor pressure fluctuations within the range of 5%of the inlet pressure will not affect the operation of the AV valves. Higherpressure variations will have to be checked and may require a change in design.In case of damage in the preheater, the level control emits an electric impulse tothe solenoid control valve, in addition to possible optical and audible warnings.The valve opens and relieves the cylinders "A" of the AV valves. Cylinders "B"receive the full pressure of the feed-water line via a small passage, whichcauses the discs to move into their closing positions. The preheater is no longerin operation and the feed-water flow passes through the by-pass line.When the solenoid control valves closes, the AV5 changeover valve will onlyremain in its closed position, if the feed-water pressure in the preheater haslowered by at least 10% as compared with the pump pressure and does notrise again. Therefore, with power test runs, the AV valves will open automatically,and the preheater is put into operation again, as soon as the solenoid controlvalve is closed. This automatic opening is effected by the valve stems beingbalanced and passed through to the outside. The pistons of the AV valves havebeen so dimensioned, that any opening towards the preheater is prevented, ifthe latter is pressureless or under low pressure. This design prevents anysudden and harmful admission of pressure to the preheater piping. For thestart-up or after repairs the preheater is filled via the refill pipe by the pump line.Only then the AV valves can be opened, or will open automatically after thepressure has been balanced within the system. With low operating pressures,the open hand-operated control valve relieves the cylinder "B" sufficiently forallowing the disc to move into its open position.

c2 *

AB

+

+

+

+

AB

c1 *

Quick - Closing Check Valves

For easy mounting of the AV valves, they should preferably be installed in verticalposition. Their pressure losses are equivalent to 90° bands and are substantiallymore advantageous as compared with T-fittings. In case of preheater groups,the valve bodies being designed as fittings, may serve for the feed-water line tobe distributed to the individual preheaters. Our technical datasheets will informyou on the possible number of connections, their relative positions and sizes.

Control Valves

The feed-water pressure being used as the source of energy for operating theAV valves necessitates minimum overpressures in the preheater system asshown in the adjoining column. Where valves are to be activated by solenoidcontrol valves at lower pressures, the AV valves will have to be modifiedaccording to individual requirements.

Equipment

The blocking stem enables the AV valves to be closed independently from thesolenoid control. The blocking stems must not be used for closing the discagainst the full operating pressure. The AV4 non return valve must not be closedbefore the AV5 changeover valve has been blocked. The blocking stem can beoperated by handwheel or by remote drives as per margin.For the maintenance of the solenoid control valve during operation, the stopvalve can be closed after the preheater protection has been changed over tobypass operation and the blocking stems have been actuated. This procedure isguaranteed by the valve interlockings SN 322 and SN 341 provided.

Design

Quick - Closing Check Valves

Check Valves AVS4. AVF4

Three way valves AVS5. AVF5

Size of seat 01 02 03 04 05 06 07 08 09 10 11 12 13 14

Maximum

Flow Quantity

Type

Cast steel DIN - PN25 -100 DIN- DIN-PN25-160PN25-40

Forged Steel DIN - PN 64- 500Control Pipes DIN-DN 15 DIN-DN 25

Control Valves

For AV Valves Close EMS1 to EMS4 Solenoid Control ValvesOther control valves on request

Open Automatically VKS11-Stop ValveMin.(bar) 40 15 15 7type Forged Steel Cast Steel Forged Steel Cast Steel

Equipment

Type ST.KG Spur Gear and bevel GearType FA Remote driving partsE-Actuators Size and connect. acc. to ISO 5210

SpecialNo. 372A2 valve interlocking

SpecialNo. 37Position Indicator“open”

SpecialNo. 36Position Indicator“closed”

* Control pipe

Time delay relais of appr. 30 sec.

Stop valveVA 500

SpecialNo. 371A4 valve interlocking (open blocked)Bypass line

* Level controlPreheater

Balance pipe

Balance valve

Outlet to Boiler

SpecialNo. 372A2 valve interlocking

SpecialNo. 36Position Indicator “closed”

SpecialNo. 37Position Indicator “open”

Time delay relais of appr. 30 sec.

* = are no part of our delivery programme

Refill valve

Refill pipe

Solenoid controlvalve EMS-

Reversing valveVA 500

Inlet from pump

AVS5

Quick closing change over valve

AVS4

Quick closing check valve

t/h 85 120

200

300

400

550

850

1200

1600

2000

2500

3000

4000

5000

Closing the solenoid control valve after changeover is necessary, because apermanent relief via the control pipe may cause erosion. As shown in thedrawing, a corresponding closing impulse is emitted by the electric indicator (SN 36) in "closed" position. Contactors C1 and C2 are lagging at approx. 30seconds.

Preheater Protection ValvesQuick closing check valve - Type AVS 4


1.3

1.7

1.2

1.1

1.8

38/39

37

14/16

17/18

2

12

20

10

58

15

33

45

31

34

55

43

41

49

46

48

29

4.1

1.5

8

4

9

22

23

24

3

27

26

11

56/57

35/36

44

5

30

45

52

51

53

47 59/59.1

42

50

Class PN

600 06 (100)900 09 (160)1500 15 (250)2500 25 (320)

Trim Body Disc Piston

seat surface seat surface rod

No Part No 1 Part No 4 Part No 5

1 17% Cr 17% Cr 13% Cr

PN 25 - 100: cast steelPN 100 - 400: forged steel



Parts list

Part Part name Material Code

01 A105 10 A182F12 11 19

1 body 1.0460 A105 1.7335 A182F12 1.5415 1.63681.1 middle part of the body 1.0460 A105 1.7335 A182F12 1.5415 1.63681.2 inlet connecting pipe 1.0460 A105 1.7335 A182F12 1.5415 1.63681.3 outlet connecting pipe 1.0460 A105 1.7335 A182F12 1.5415 1.63681.5 hardfacing Chromium steel Chromium steel Chromium steel Chromium steel Chromium steel Chromium steel1.7 welding seam1.8 welding seam2 cover 1.0460 A105 1.7335 A182F12 1.5415 1.63683 cylinder 1.4008 / 1.4008 / 1.4008 / 1.4008 / 1.4008 / 1.4008 /

part. Cr-plated part. Cr-plated part. Cr-plated part. Cr-plated part. Cr-plated part. Cr-plated4 disc 1.0460 A105 1.7335 A182F12 1.5415 1.63684.1 hardfacing Chromium steel Chromium steel Chromium steel Chromium steel5 rod with piston 1.4021 / 1.4021 / 1.4021 / 1.4021 /

par. Cr-plated par. Cr-plated par. Cr-plated par. Cr-plated8 disc stem connection 1.7335 1.7335 1.7335 1.73359 split ring 1.7335 1.7335 1.7335 1.733510 ring 1.0425 1.0425 1.0425 1.042511 tightening plate 1.0425 1.0425 1.0425 1.042512 split ring 1.0460 1.0460 1.0460 1.046014 convex seal 1.4541 1.4541 1.4541 1.454115 flange 1.7335 1.7335 1.7335 1.733516 control stud 1.7335 1.7335 1.7335 1.733517 bolt 1.7709 1.7709 1.7709 1.770918 hexagonal nut 1.7258 1.7258 1.7258 1.725820 piston ring 1.4086 1.4086 1.4086 1.408622 segment ring 1.7380 A182F22 1.7380 A182F22 1.7380 1.636823 ring 1.0460 A105 1.7335 A182F22 1.5415 1.636824 cover seal Graphit/1.4541 Graphit/1.4541 Graphit/1.4541 Graphit/1.454126 base ring 1.4021 1.4021 1.4021 1.402127 packing Graphit Graphit Graphit Graphit29 gland shaft 1.4021 1.4021 1.4021 1.402130 gland flange 1.0460 1.7335 1.7335 1.733531 stud 1.1181 1.1181 1.1181 1.118133 washer Ferrite Ferrite Ferrite Ferrite34 hexagonal nut 1.0501 1.0501 1.0501 1.050135 stud 1.1181 1.1181 1.1181 1.118136 hexagonal nut 1.0501 1.0501 1.0501 1.050137 allan bolt A4 A4 A4 A438 name plate 1.4541 1.4541 1.4541 1.454139 roundheaded notched nail Austenite Austenite Austenite Austenite41 bonnet Divers Divers Divers Divers42 spindle 1.4021 1.4021 1.4021 1.402143 indicator ring 1.0460 1.0460 1.0460 1.046044 indicator ring 1.0460 1.0460 1.0460 1.046045 guide bolt 1.4122 1.4122 1.4122 1.412246 threaded bush 2.0550 2.0550 2.0550 2.055047 ring bearing 1.0060 1.0060 1.0060 1.006048 axial-needle bearing ball bearing steel ball bearing steel ball bearing steel ball bearing steel49 threaded pin Ferrite Ferrite Ferrite Ferrite50 pipe nut Ferrite Ferrite Ferrite Ferrite51 fitting key 1.0503 1.0503 1.0503 1.050352 hand wheel 0.6025 0.6025 0.6025 0.602553 lubrication nipple Ferrite Ferrite Ferrite Ferrite55 tightening pin Springsteel Springsteel Springsteel Springsteel58 bonnet holder Divers Divers Divers Divers59 limit switch Divers Divers Divers Divers59.1 allan bolt 8.8 8.8 8.8 8.8



Welding Ends

PN Size of Seat diameter DN Inlet DN Outlet Bypass Dimensions in mm Weight

seat mm mm mm mm S H1 H2 H3 h D a c kg

160/500 01 75 80-125 80 50-80 230 665 615 555 35 400 140 235 100100-125 100 50-100 250 110

125 125 50-125 250 12002 90 100-150 100 65-100 250 665 615 555 35 400 140 235 140

125-150 125 65-125 275 155150 150 65-150 275 170

160/400 03 115 125-175 125 80-125 300 825 735 675 50 400 330 200 200150-175 150 80-150 325 230

175 175 80-175 325 26004 140 150-200 150 100-150 325 825 735 675 50 400 330 200 300

175-200 175 100-175 350 340200 200 100-200 350 390

05 165 175-250 175 125-175 350 895 825 755 60 560 390 220 420200 200 125-200 375 490250 200 125-200 375 560

06 190 200-300 200 125-200 375 895 825 755 60 560 390 220 600250 250 125-250 400 700300 250 125-250 400 800

07 240 250-350 250 150-250 425 1120 1020 940 80 560 490 235 900300 300 150-300 475 1000350 300 150-300 475 1100

075 260 250-350 250 150-250 425 1120 1020 940 80 560 490 235 900300 300 150-300 475 1000350 300 150-300 475 1100

08 290 300-350 300 150-300 525 1140 1030 940 90 560 490 245 1300400 300 150-300 550 1400

350-400 350 150-350 550 1500085 310 300-350 300 150-300 525 1140 1030 940 90 560 490 245 1300

400 300 150-300 550 1400350-400 350 150-350 550 1500

09 335 350-400 350 200-350 575 1295 1160 1080 105 800 530 270 2000450 350 200-300 625 2200

400-450 400 200-400 625 2400095 360 350-400 350 200-350 575 1295 1160 1080 105 800 530 270 2000

450 350 200-300 625 2200400-450 400 200-400 625 2400

10 375 400-450 400 250-400 625 1300 1160 1180 115 800 565 285 3000500 400 250-400 625 3400

450-500 450 250-450 625 3800105 400 400-450 400 250-400 625 1300 1160 1180 115 800 565 285 3000

500 400 250-400 625 3400450-500 450 250-450 625 3800

Welding ends as specified by customer

Preheater Protection ValvesQuick closing three-way valve - Type AVS 5


zum Handventil

to stop valve

zum Steuerventil

to control valve2.1

39

1.5

1.21.7

4.1

2.2

to control valve

zum Steuerventil

zum Handventilto stop valve

39

23

4.2

3

37

2420

14/1617/18

121022

58

1531

33

38/39

34

55

43

41

45

494846

8

1.1

1.31.8

94

29

21

1.6

1.41.9

2

11

56/5735/3660

26/2730

5

4544

5159/59.1

53

47

52

5042

Class PN

600 06 (100)900 09 (160)1500 15 (250)2500 25 (320)

Trim Body Disc Piston

seat surface seat surface rod

No Part No 1 Part No 4 Part No 5

1 17% Cr 17% Cr 13% Cr

PN 25 - 100: cast steelPN 100 - 400: forged steel



Parts list

Part Part name Material Code

01 A105 10 A182F12 11 19

1 body 1.0460 A105 1.7335 A182F12 1.5415 1.63681.1 middle part of the body 1.0460 A105 1.7335 A182F12 1.5415 1.63681.2 inlet connecting pipe 1.0460 A105 1.7335 A182F12 1.5415 1.63681.3 outlet connecting pipe 1.0460 A105 1.7335 A182F12 1.5415 1.63681.4 bypass connecting pipe 1.0460 A105 1.7335 A182F12 1.5415 1.63681.5 hardfacing Chromium steel Chromium steel Chromium steel Chromium steel Chromium steel Chromium steel1.6 hardfacing Chromium steel Chromium steel Chromium steel Chromium steel Chromium steel Chromium steel1.7 welding seam1.8 welding seam1.9 welding seam2 cover 1.0460 A105 1.7335 A182F12 1.5415 1.63682.1 indication plate 1.4541 1.4541 1.4541 1.4541 1.4541 1.45412.2 indication plate 1.4541 1.4541 1.4541 1.4541 1.4541 1.45413 cylinder 1.4008 / 1.4008 / 1.4008 / 1.4008 / 1.4008 / 1.4008 /

part. Cr-plated part. Cr-plated part. Cr-plated part. Cr-plated part. Cr-plated part. Cr-plated4 disc 1.0460 A105 1.7335 A182F12 1.5415 1.63684.1 hardfacing Chromium steel Chromium steel Chromium steel Chromium steel4.2 hardfacing Chromium steel Chromium steel Chromium steel Chromium steel5 rod with piston 1.4021 / 1.4021 / 1.4021 / 1.4021 /

par. Cr-plated par. Cr-plated par. Cr-plated par. Cr-plated8 disc stem connection 1.7335 1.7335 1.7335 1.73359 split ring 1.7335 1.7335 1.7335 1.733510 ring 1.0425 1.0425 1.0425 1.042511 tightening plate 1.0425 1.0425 1.0425 1.042512 split ring 1.0460 1.0460 1.0460 1.046014 convex seal 1.4541 1.4541 1.4541 1.454115 flange 1.7335 1.7335 1.7335 1.733516 control stud 1.7335 1.7335 1.7335 1.733517 bolt 1.7709 1.7709 1.7709 1.770918 hexagonal nut 1.7258 1.7258 1.7258 1.725820 piston ring 1.4086 1.4086 1.4086 1.408621 piston ring 1.4086 1.4086 1.4086 1.408622 segment ring 1.7380 A182F22 1.7380 A182F22 1.7380 1.636823 ring 1.0460 A 105 1.7335 A182F12 1.5415 1.636824 cover seal Graphit/1.4541 Graphit/1.4541 Graphit/1.4541 Graphit/1.4541 Graphit/1.454126 base ring 1.4021 1.4021 1.4021 1.402127 packing Graphit Graphit Graphit Graphit29 gland shaft 1.4021 1.4021 1.4021 1.402130 gland flange 1.0460 1.7335 1.7335 1.733531 stud 1.1181 1.1181 1.1181 1.118133 washer Ferrite Ferrite Ferrite Ferrite34 hexagonal nut 1.0501 1.0501 1.0501 1.050135 stud 1.1181 1.1181 1.1181 1.118136 hexagonal nut 1.0501 1.0501 1.0501 1.050137 allan bolt A4 A4 A4 A438 name plate 1.4541 1.4541 1.4541 1.454139 roundheaded notched nail Austenite Austenite Austenite Austenite41 bonnet Divers Divers Divers Divers42 spindle 1.4021 1.4021 1.4021 1.402143 indicator ring 1.0460 1.0460 1.0460 1.046044 indicator ring 1.0460 1.0460 1.0460 1.046045 guide bolt 1.4122 1.4122 1.4122 1.412246 threaded bush 2.0550 2.0550 2.0550 2.055047 ring bearing 1.0060 1.0060 1.0060 1.006048 axial-needle bearing ball bearing steel ball bearing steel ball bearing steel ball bearing steel49 threaded pin Ferrite Ferrite Ferrite Ferrite50 pipe nut Ferrite Ferrite Ferrite Ferrite51 fitting key 1.0503 1.0503 1.0503 1.050352 hand wheel 0.6025 0.6025 0.6025 0.602553 lubrication nipple Ferrite Ferrite Ferrite Ferrite55 tightening pin Springsteel Springsteel Springsteel Springsteel56 stud 1.1181 1.1181 1.1181 1.118157 hexagonal nut 1.0501 1.0501 1.0501 1.050158 bonnet holder Divers Divers Divers Divers59 limit switch Divers Divers Divers Divers59.1 allan bolt 8.8 8.8 8.8 8.860 manual control valve Divers Divers Divers Divers



Welding Ends

PN Size of Seat diameter DN Inlet DN Outlet Bypass Dimensions in mm Weight

seat mm mm mm mm S H1 H2 H3 h D a c kg

160/500 01 75 80-125 80 50-80 230 665 615 555 35 400 140 235 100100-125 100 50-100 250 110

125 125 50-125 250 12002 90 100-150 100 65-100 250 665 615 555 35 400 140 235 140

125-150 125 65-125 275 150150 150 65-150 275 170

160/400 03 115 125-175 125 80-125 300 825 735 675 50 400 330 200 200150-175 150 80-150 325 230

175 175 80-175 325 26004 140 150-200 150 100-150 325 825 735 675 50 400 330 200 300

175-200 175 100-175 350 340200 200 100-200 350 390

05 165 175-250 175 125-175 350 895 825 755 60 560 390 220 420200 200 125-200 375 490250 200 125-200 375 560

06 190 200-300 200 125-200 375 895 825 755 60 560 390 220 600250 250 125-250 400 700300 250 125-250 400 800

07 240 250-350 250 150-250 425 1120 1020 940 80 560 490 235 900300 300 150-300 475 1000350 300 150-300 475 1100

075 260 250-350 250 150-250 425 1120 1020 940 80 560 490 235 900300 300 150-300 475 1000350 300 150-300 475 1100

08 290 300-350 300 150-350 525 1140 1030 940 90 560 490 245 1300400 300 150-300 550 1400

350-400 350 150-350 550 1500085 310 300-350 300 150-350 525 1140 1030 940 90 560 490 245 1300

400 300 150-300 550 1400350-400 350 150-350 550 1500

09 335 350-400 350 200-350 575 1295 1160 1080 105 800 530 270 2000450 350 200-300 625 2200

400-450 400 200-400 625 2400095 360 350-400 350 200-350 575 1295 1160 1080 105 800 530 270 2000

450 350 200-300 625 2200400-450 400 200-400 625 2400

10 375 400-450 400 250-400 625 1300 1160 1180 115 800 565 285 3000500 400 250-400 625 3400

450-500 450 250-450 625 3800105 400 400-450 400 250-400 625 1300 1160 1180 115 800 565 285 3000

500 400 250-400 625 3400450-500 450 250-450 625 3800

Welding ends as specified by customer



2.3

8

9

5

3

2.6

2.52.5

2.4

2.1

1

6

4

2.2

Parts list

1 Pickling cylinder2.1 Pickling disc2.2 Pickling stem2.3 Tightening screw2.4 Sealing plate2.5 Holding plate2.6 Allan bolt3 Guide ring4 Guide bolt5 Dummy convex seal6 Packing8 Allan bolt9 Gasket

AVS4.02.160.100.150.125.125.80. 10..43.66 Example for designation of check valves

Standard accessoriesMaterial SpecificationSize of extra connections

Outlet nominal sizeInlet Nominal SizeNominal PressureSeat sizeType of Valve, abbr.

Locations of connections for seat sizes 03-10

The maximum number of connections of the outlet plane is 4 of limited size. There must be atleast 90° between adjacent connections. Their number, sizes and angular positions must bestated upon ordering or inquiring.The angular positions of the control connection (16) is independent of the connections of the valvebody. It can be fixed in any desired position after loosening the hexagonal nuts (36, 57, 58.2).Where an extra manual control valve SN 66 is employed, it should be fitted exactly opposite (180°)to the control connection (16).



AVS5.02.160.150.100.80.125.125. 10.43.74 Example for designation of three-way-valves

Standard accessoriesMaterial SpecificationSize of extra connectionsBypass nominal sizeOutlet nominal sizeInlet Nominal SizeNominal PressureSeat sizeType of Valve, abbr.

2.5

2.6

2.4

2.1

2.3

9

1

8

7

5

5

3

6

4

2.2

Parts list

1 Pickling cylinder2.1 Pickling disc2.2 Pickling stem2.3 Tightening screw2.4 Holding plate2.5 Allan bolt2.6 Allan bolt3 Guide ring4 Guide bolt5 Dummy convex seal6 Packing7 O-Ring8 Allan bolt9 Gasket

Locations of connections for seat sizes 03-10

Maximum number of connections of the inlet and bypass plane is 4 of limited size. There must beat least 90° between adjacent connections. Their number, sizes and angular positions must bestated upon ordering or inquiring. Normally the control connection (16) is positioned above theinlet connection (1.2) and the manual control valve (61) is placed at 180°C to the controlconnection. It can, however, be fixed in any position after loosening the hexagonal nuts (36, 57,58.2), provided the position of connection and valve remains unchanged with reference to theiropposite position of 180°.

Preheater Protection ValvesSolenoid control valve - Type EMS 3-4 and EMF 3-4


6

12

9

5

3

2

8

7

10

4

111

8

7

10

11

4

5

12

6

9

1

3

2

AVS4

AVS5

Parts list ASV4

1 Lid2 Tightening screw3 Threaded stem4 Hexagonal nut5 Tightening plate6 Shutt off plate7 O-Ring8 O-Ring9 O-Ring10 Ring screw11 Safety ring12 Cylinder slotted pin

Parts list ASV5

1 Lid2 Tightening screw3 Threaded stem4 Hexagonal nut5 Tightening plate6 Shutt off plate7 O-Ring8 O-Ring9 O-Ring10 Ring screw11 Safety ring12 Cylinder slotted pin



Standard AccessoriesManual Control Valve (SN 66).



Y

Z

Standard AccessoriesHydraulic brake to increase opening and closing times by several seconds (SN 74).

Detail Y

Detail Z



E M S 3 .15 - 10 .112 Example for Solenoid Control ValveSpecification

Standard accessoriesMaterials SpecificationInlet Nominal SizeControl PrincipleOutlet ConnectionSolenoid ControlAngle Type Body

Installation

Solenoid Control Valves are designed to quickly and reliably believe and load the control chambersof valves controlled by their own medium. They are employed for activating preheater safetydevices, quick-closing and opening valves as well as controlled safety relief valves. Their inlet iseither directly connected to the standard connections of the controls or through the intermediaryof control pipes. Existing safety regulations should be adhered to. Maximum nominal pressuresmust not be exceeded, and control pipes should not be smaller in diameter than the connectionsof the control valves. Suitable controlling instruments may be connected to the respective bores.

Design

Materials are specified for all parts exposed to pressure, for those giving tight seal to atmosphereand for spares. Inlet connection (3) is also available in different materials if local operatingconditions should render it necessary. Other material specifications on request. All major internalparts are made from high-alloyed, wear resistant materials with guaranteed physical propertiesand coefficients of expansion. In case of damage, e.g. by foreign matter or where parts are wornafter continuous heavy service, exchange of such parts is recommended by making use of our exstore spare kits. Please state rating plate particulars when ordering or inquiring.

Table ???

Operation

EMS3 . EMF3 De-energized, Solenoid Valve Open, indirect operationWith Solenoid (57) de-energized, disc (29) is pushed into " open "position against the servicepressure by the biased cup springs via stem (40). The upper side of the check disc (25) becomespressureless and moves upward into "open "position. Upon the current being switched on,solenoid (57) will return to its initial position against the force of the cup springs. Spring (30)assisted by the service pressure causes disc (29) to close smartly onto its seat. This closing actionis also assisted by the service pressure generating above check disc (25).

EMS4.EMSF4 Energized, Solenoid Valve Open, indirect operationWith Solenoid (57) energized, disc (29) is pushed into" open" position against the service pressureby magnetic force via stem (40). The upper side of the check disc (25) becomes pressureless andmoves upward into "open" position. Upon the current being switched off, pressure spring pullssolenoid (57) back to its initial position. Spring (30) with the aid of the service pressure pushes disc(29) into closed position. This closing action is also assisted by the service pressure generatingabove disc (25).

typical feed water heater isolation system. -...

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