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Piston Valve

piston valve
piston valve 1

Sizes and Pipe Connection

  • 1.DN 15/20/25/32/40 Screwed BSPT/NPT, socket weld ends, flanged to class 150/300/600 available on special request

  • 2. DN 50/65/80/100/125/150/200/250 Flanged to class 150/300

  • 3. DN 50/65/80/100/125/150/200/250 Flanged to PN16/PN25/PN40

  • For higher sizes DN 250 and 300 contact Forbes Marshall

Limiting Conditions

For DN 15/20/25/32/40 Socket weld ends
Maximum operating pressure 78 bar g
Maximum operating temperature 425 deg c
Maximum hydraulic test pressure 156 bar g (IBR requirement)
For DN 15/20/25 Screwed ends
Maximum operating pressure 78 bar g
Maximum operating temperature 425 deg c
Maximum hydraulic test pressure 156 bar g (IBR requirement)
For DN 32/40 Screwed ends
Maximum operating pressure 41.5 bar g
Maximum operating temperature 425 deg C
Maximum hydraulic test pressure 83 bar g (IBR requirement).

Material: DN 15-40

Sr.No Description Material
1 Body Forged Carbon Steel ASTM A105N
2 Bonnet Forged Carbon Steel ASTM A105N
3 Piston Stainless Steel ASTM A 276 TYPE 304
4 Spindle Stainless Steel ASTM A 276 TYPE 410
5 Nyloc Nut Carbon Steel
6 Stud Carbon Steel ASTM A193 Gr. B7
7 Nut Carbon Steel ASTM A 194 Gr.2H
8 Belleville Washer Spring Steel 50CrV4
9 Sealing stack S.S. Reinforced Graphite
10 Spacer Stainless Steel ASTM A 276 TYPE 410
11 *Handwheel Sheet Metal / SG Iron
12 Gap rings Stainless Steel 410
13 Split Nut Brass DIN En12164
14 Thrust Plate Stainless Steel ASTM A 275 TYPE 420
*Note: For DN 15-25 Handwheel - Sheet Metal For DN32-40 Hand wheel-S.G. Iron

Body design conditions:DN 15/20/25/32/40 Class 600 Flanged ends

Maximum allowable pressure 102 bar g @ 38 °C
Maximum operating pressure 78 bar g @ 295 °C
Maximum operating temperature 425 °C @ 57.5 bar g
Maximum hydraulic test pressure 156 bar g

Dimensions (approx. in mm)

Size (DN) A B C
15 110 118 146
20 110 118 146
25 126 133 133
32 165 175 215
40 165 175 215

Flange Class

Size (DN) A* C B
Class 150 Class 300 Class 600
265 15 252 265 118 146
20 252 265 265 118 146
25 260 278 278 133 165
32 305 317 320 175 215
40 305 317 320 175 215
piston valve 2
piston valve 3

Body design conditions: DN 50-200 PN 16 Flanged End

Maximum allowable pressure 16 bar g at 38 deg C
Maximum operating pressure 16 bar g at 204 deg C
Maximum operating temperature 425 deg C at 9.1 bar g
Cold hydraulic test pressure 24 bar g

Body design conditions: DN 50-150 PN 25 Flanged End

Maximum allowable pressure 25 bar g at 38 deg C
Maximum operating pressure 25 bar g at 226 deg C
Maximum operating temperature 425 deg C at 14 bar g
Cold hydraulic test pressure 38 bar g

Body design conditions: DN 50-200 PN 40 Flanged End

Maximum allowable pressure 40 bar g at 38 deg C
Maximum operating pressure 39 bar g at 250 deg C
Maximum operating temperature 425 deg C at 22.8 bar g
Cold hydraulic test pressure 60 bar g

Body design conditions: DN 50/65/80/100/150/200/250 Class 150 Flanged ends

Maximum allowable pressure 19,6 bar g at 38 deg C
Maximum operating pressure 14 bar g at 197 deg C
Maximum operating temperature 425 deg C at 5.5 bar g
Cold hydraulic test pressure 28 bar g (IBR requirement)

Material: DN 50

Sr.No. Description Material
1 Body Cast Steel ASTM A 216 Gr.WCB
2 Bonnet Cast Steel ASTM A 216 Gr.WCB
3 Piston Stainless Steel ASTM A 276 TYPE 304
4 Spindle Stainless Steel ASTM A 276 TYPE 410
5 Nyloc Nut Carbon Steel
6 Stud Carbon Steel ASTM A193 Gr. B7
7 Nut Carbon Steel ASTM A 194 Gr.2H
8 Belleville Washer Spring Steel 50CrV4
9 Sealing stack S/S Reinforced Graphite
10 Spacer Stainless Steel ASTM A 743 Gr.CA15
11 Handwheel SG Iron
12 Thrust Plate Stainless Steel ASTM A 276 TYPE 420
13 Name Plate Stainless Steel ASTM A 240 TYPE 304
14 Split Nut Brass DIN EN 12164
15 Gap Rings Stainless Steel SS 420

Body design conditions: Class 300 Flanged End

Maximum allowable pressure 51 bar g at 38 deg C
Maximum operating pressure 41,5 bar g at 253 deg C
Maximum operating temperature 425 deg C at 28,8 bar g
Cold hydraulic test pressure 83 bar g (IBR requirement)

Dimensions (approx. in mm): Size DN 50

ANSI Class L D PCD H No. of Holes T E F Approx Wt
150 203 152 121 19 4 19 210 262 14.5 kg
200 267 165 127 19 8 22 210 262 17.5 kg
PN 16 230 165 125 18 4 18 210 262 14.5 kg
PN 40 230 165 125 18 4 20 210 262 17.5 kg

Material: DN 65-250

Sr.No. Description Material
1 Body Cast Steel ASTM A 216 Gr.WCB
2 Bonnet Cast Steel ASTM A 216 Gr.WCB
3 Piston Stainless Steel ASTM A 351 CF8
4 Body sealing stack S/S Reinforced Graphite
5 Spacer Stainless Steel ASTM A 743 CA 15
6 Spindle Stainless Steel ASTM A 276 Type 410
7 Stem Stainless Steel ASTM A 276 Type 304
8 Split Nut Brass DIN EN 12164
9 LH Nut Stainless Steel ASTM A 276 Type 304
10 Gland Sealing Stack S/S Reinforced Graphite
11 Threaded Bush Ph. Bronze
12 Back Seat Stainless Steel ASTM A 276 Type 410
13 Gland Nut Stainless Steel ASTM A 194 Gr.2H
14 Bonnet Sealing Ring Graphite
15 Stud Carbon Steel ASTM A 193 Gr.B7
16 Nut Carbon Steel ASTM A 194 Gr.2H
17 Beleville Washer Spring Steel 50CrV4
18 Handwheel S.G. Iron
19 Nyloc Nut Carbon Steel
20 Washer ASTM A 240 TYPE 304 Stainless Steel
21 Name Plate Stainless Steel ASTM A 240 TYPE 304
22 Thrust Plate Stainless Steel ASTM A 276 TYPE 420
23 Gap Rings Stainless Steel SS420

Dimensions (approx. in mm): Size DN 65 to 250

Sizes (DN) Pressure Class L D PCD H NO. OF Holes T E F Approx. Weight (Kg)
65 CLASS 300 292 191 149 22 8 25 335 400 31
65 CLASS 150 216 178 140 19 4 22 335 400 27
65 PN 16/25 290 185 145 18 8 18 335 400 27
65 PN40 290 185 145 18 8 22 335 400 31
80 CLASS 300 318 210 168 22 8 28 320 384 37
80 CLASS 150 241 191 152 19 4 24 320 384 31
80 PN 16/25 310 200 160 18 8 24 320 384 31
80 PN 40 310 200 168 18 8 20 320 479 37
100 CLASS 300 356 254 200 22 8 32 395 479 58
100 CLASS 150 292 229 191 19 8 24 395 479 47
100 PN 16/25 350 220 180 20 8 18 395 479 47
100 PN 40 350 235 190 24 8 22 395 479 58
125 CLASS 300 400 280 235 24 8 35 446 540 87
125 CLASS 150 356 254 216 22 8 24 446 540 70
125 PN 16/25 400 250 210 18 8 22 446 540 70
125 PN 40 400 270 220 26 8 26 446 540 87
150 CLASS 300 445 318 270 22 12 37 486 598 117
150 CLASS 150 406 279 241 22 8 26 486 598 90
150 PN 16/25 480 285 240 22 8 22 486 598 90
150 PN 40 480 300 250 26 8 28 486 598 117
200 CLASS 300 559 381 330 25 12 41 591 728 210
200 CLASS 150 495 343 298 22 8 28 591 728 164
200 PN 16/25 600 340 295 22 12 24 591 728 164
200 PN 40 600 375 320 30 12 34 591 728 210
250 CLASS 300 622 455 381 26 16 48 653 813 340
250 CLASS 150 622 405 362 25 12 31 653 813 300
*250 PN 16/25 730 405 355 26 12 26 653 813 340
*250 PN 40 730 450 385 33 12 38 653 813 370
*For DN250 Class PN16/25 and PN40, please contact Forbes Marshall

Installation

The valve is designed for installation in a vertical or horizontal line with inlet as per the arrow direction. To open the valve turn hand wheel till it stops at the top and to close, turn hand wheel till it touches the bonnet. Do not use "F" key. If any leakage is observed during operation at the outlet, close valve fully and tighten opposite nuts equally half or one turn until leakage stops.

Safety Information

Pressure: Before attempting any maintenance of the valve, ensure that pressure is isolated and safely vented to atmosphere. Do not assume that the system is depressurized even when a pressure gauge indicates zero.

Maintenance

Use Molykote M30 oil for lubrication. For DN 15-50 sizes lubricate spindle regularly through bonnet hole and spindle threads. For DN 65-250 lubricate frequently through spindle threads, split nut and stem.

How to Order Spares

Order spares as per the code no. specified in the user manual.

For Bonnet Nut

Sr. No. Size (DN) Torque (Nm)
1 15 3-5
2 20
3 25 5-7
4 32
5 40 18-20
6 50
7 65 20-25
7 65
8 80 50-60
10 125
11 150 70-80
12 200
13 250 80-90

For Gland Nut

Sr. No. Size (DN) Torque (Nm)
1 65 35-45
2 80 35-45
3 100 75-85
4 125 75-85
5 150 85-95
6 200 95-110
7 250 95-110

Available Spares

DN 15-50 Sealing stacks
DN 65-250 Body sealing stack set, bonnet sealing ring and gland sealing stack

Kv Values

Size (DN) 15 20 25 32 40 50 65 80 100 125 150 200 250
Kv 2.5 2.5 5.8 13 13 41 51 77 131 194 221 438 675
piston valve 5
piston valve 6
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