Pneumatic Cryogenic Double Seat Control Valve
Pneumatic Cryogenic Double Seat Control Valve
Pneumatic Cryogenic Double Seat Control Valve
Pneumatic Cryogenic Double Seat Control Valve

Pneumatic Cryogenic Double Seat Control Valve

  • Cryogenic double-seat control valve with long-neck bonnet for -60 ~ -250°C media such as liquid oxygen and liquid nitrogen
  • Pneumatic diaphragm actuator; positioner required; air-to-close (B) and air-to-open (K) action
  • DN20-200 single-seat, DN25-200 double-seat; Kv 0.08-630; linear or equal-percentage characteristic

Category

Overview

ZMAN-16D pneumatic cryogenic double-seat control valve is a derivative of single-seat and double-seat control valves. Unlike valves used at normal temperature, it features a long-neck type upper bonnet that keeps the packing at ambient temperature. It is suitable for regulating cryogenic media at -60 ~ -250°C, such as liquid oxygen and liquid nitrogen. To ensure regulation accuracy, a positioner must be used.

Structure Principle

The pneumatic cryogenic control valve consists of a pneumatic diaphragm actuator and a cryogenic-resistant single-seat or double-seat valve body. The signal pressure from the controller enters the air chamber of the pneumatic diaphragm actuator to produce thrust, which drives the valve plug through connecting rods. The change of the plug position varies the flow area of the valve, thereby regulating the medium flow rate.

Technical Parameters

Nominal Diameter DN
Single-seat
20
25
32
40
50
65
80
100
125
150
200
Double-seat 25 32 40 50 65 80 100 125 150 200
Rated Flow Coefficient Kv Single-seat 0.08 0.12 0.20 0.32 0.50 0.80 1.2 2.0 3.2 5.0 8 12 20 32 50 80 120 200 280 450
Double-seat 10 16 25 40 63 100 160 250 400 630
Flow Characteristic Linear Linear; Equal percentage
Actuator Model ZMA-2 ZMA-3 ZMA-4 ZMA-5
Stroke (mm) 10 10 16 25 40 60
Action Type Air-to-close (B), air-to-open (K)
Spring Pressure Range (kPa) Standard signal: 20~100; other signals: 40~200; 20~60; 60~100

Installation Precautions

  • The valve shall be installed vertically on a horizontal pipeline. When horizontal or inclined installation is necessary under special circumstances, supports should generally be added. The disc plate installed on the wall of the insulation box should be parallel to the wall of the box.
  • It should be installed close to the floor or the floor slab to facilitate maintenance and repair. For valves equipped with a positioner or handwheel mechanism, observation, adjustment and operation should be ensured.
  • A bypass pipeline is generally provided so that when the automatic control system fails or during maintenance, manual operation can be switched to without stopping production.
  • When a handwheel mechanism is installed, manual operation can be performed without a bypass pipeline, and it can also be used to limit the opening. When not in use, the handwheel mechanism must be returned to its original neutral position to keep the automatic control system operating normally.
  • During installation, the medium flow direction should be consistent with the direction indicated on the valve body.
  • Before installation, the pipeline should be cleaned of dirt and welding slag. After installation, the valve should be fully opened to clean the pipeline and test the sealing of all connections.

Overall Dimensions

Nominal Diameter DN (mm)
 
20
25
32
40
50
65
80
100
125
150
200
A 230 280 280 325 410 495
135 235 235 255 280 310 345 370 430 470 550 660
1 160 260 260 285 305 340 375 405 460 525 590 700
2 190 290 290 315 335 370 410 440 490 560 630 740
n- 6-12 8-14 8-14 8-14 8-16 10-16 10-18 12-18 16-18 20-18
Single-seat H L 120 190 200 210 235 265 295 320 370 440 475 570
H1=500 862 1006 1060 1066 1137 1152 1377 1390 1394
H1=600 962 1106 1160 1166 1237 1252 1477 1490 1494
H1=700 1062 1206 1260 1266 1337 1352 1577 1590 1594 1743 1751 1790
H1=800 1162 1306 1360 1366 1437 1452 1677 1690 1694 1843 1851 1890
H1=900 1262 1406 1460 1466 1537 1552 1777 1790 1794 1943 1951 1990
H1=1000 1362 1506 1560 1566 1637 1652 1877 1890 1894 2043 2051 2090
H1=1100 2143 2150 2190
H1=1200 2243 2250 2290
H2 32 58 112 118 129 144 178 191 195 243 251 290
Double-seat H L 200 210 235 265 295 320 370 440 475 570
H1=500 1065 1068 1147 1152 1387 1407 1419
H1=600 1165 1168 1247 1252 1487 1507 1519
H1=700 1265 1268 1347 1352 1587 1607 1619 1768 1778 1820
H1=800 1365 1368 1447 1452 1687 1607 1719 1868 1878 1920
H1=900 1465 1468 1547 1552 1787 1807 1819 1968 1978 2020
H1=1000 1565 1568 1647 1652 1887 1907 1919 2068 2078 2120
H1=1100 2168 2178 2220
H1=1200 2268 2278 2320
H2 117 120 139 144 188 208 208 268 278 320

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