NKZ Series Vacuum Isolation Parallel Double Disc Gate Valve
NKZ series vacuum isolation parallel double disc gate valve is designed for water, steam and air pipelines up to 425°C or 550°C. With vacuum sealing packing, parallel double disc sealing and flanged or welded connections, it is especially suitable for turbine condenser and vacuum negative-pressure systems in thermal power plants.
Description
NKZ Series Vacuum Isolation Parallel Double Disc Gate Valve
The NKZ series vacuum isolation parallel double disc gate valve is designed for
water, steam and air pipelines operating at temperatures up to 425°C or 550°C.
It is available with flanged or welded connections and can be operated manually
or by an electric actuator.
The valve is especially suitable for turbine condenser systems and vacuum
negative-pressure systems in thermal power plants. Its vacuum sealing structure
isolates the pipeline system from the atmosphere and provides reliable vacuum
isolation performance.
Main Features
- Available with flanged or welded connections.
- Manual and electric actuation options.
- Vacuum sealing packing chamber isolates the system from the atmosphere.
- Excellent environmental sealing performance.
- Parallel double disc gate provides bidirectional elastic sealing.
- Low friction and smooth opening and closing operation.
- Reliable sealing performance and convenient maintenance.
- Stem is heat-treated and surface-nitrided for corrosion and wear resistance.
- Composite flange gasket provides excellent air-tightness.
- Suitable for turbine condenser and vacuum negative-pressure systems.
Pressure Test Data
| Nominal Pressure PN (MPa) | Shell Strength Test (MPa) | Back Seat Test (MPa) | Seat Test (MPa) |
|---|---|---|---|
| 1.0 | 1.5 | 1.1 | 1.1 |
| 1.6 | 2.4 | 1.8 | 1.8 |
| 2.5 | 3.8 | 2.8 | 2.8 |
| 4.0 | 6.0 | 4.4 | 4.4 |
| 6.4 | 8.6 | 7.0 | 7.0 |
| 10.0 | 15.0 | 11.0 | 11.0 |
Applicable Service Range
| Product Type | Applicable Medium | Maximum Temperature |
|---|---|---|
| NKZ41H, NKZ44H, NKZ944H-C, NKZ941H | Water, steam and air | ≤425°C |
| NKZ41H(Y), NKZ44H(Y)-I, NKZ944H(Y)-I, NKZ941H(Y) | Water, steam and air | ≤550°C |
Materials for Main Parts
| Model Series | Body and Bonnet | Stem | Gate | Sealing Face | Stem Nut | Packing | Fasteners |
|---|---|---|---|---|---|---|---|
| NKZ44H / NKZ41H-C / NKZ944H-C / NKZ941H | WCB | 2Cr13 | 25 | Alloy steel | Aluminium bronze | Expanding composite graphite | High-grade carbon steel |
| NKZ44 / NKZ41Y-I / NKZ944-I / NKZ941 | Chromium-molybdenum steel | 20CrMo1VA / 38CrMoAlA | Chromium-molybdenum steel | Hard alloy | Chromium-molybdenum steel | Expanding composite graphite | Chromium-molybdenum steel |
Typical Applications
- Thermal power plant turbine condenser systems
- Vacuum negative-pressure pipelines
- Steam pipelines
- Water supply systems
- Compressed air and industrial air systems
- Vacuum isolation and atmospheric isolation service
Main Dimensions and Weight
| DN (mm) | PN (MPa) | Main External and Connecting Dimensions (mm) | Valve Weight (kg) | Additional Flange Dimensions (mm) | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| L | H | D | D1 | D2 | b | f | z-d | W | h | D0 | Dn | |||
| 50 | 1.0 | 250 | 345 | 160 | 125 | 100 | 16 | 3 | 4-18 | 250 | 28 | 45 | 49 | 58 |
| 65 | 1.0 | 270 | 395 | 180 | 145 | 120 | 18 | 3 | 4-18 | 250 | 40 | 48 | 64 | 75 |
| 80 | 1.0 | 280 | 425 | 195 | 160 | 135 | 20 | 3 | 4-18 | 300 | 55 | 50 | 78 | 97 |
| 100 | 1.0 | 300 | 510 | 215 | 180 | 155 | 20 | 3 | 8-18 | 300 | 72 | 52 | 96 | 110 |
| 125 | 1.0 | 325 | 570 | 245 | 210 | 185 | 22 | 3 | 8-18 | 350 | 106 | 60 | 120 | 136 |
| 150 | 1.0 | 350 | 725 | 280 | 240 | 210 | 24 | 3 | 8-18 | 350 | 146 | 60 | 145 | 163 |
| 200 | 1.0 | 400 | 820 | 335 | 295 | 265 | 26 | 3 | 8-18 | 400 | 220 | 62 | 202 | 223 |
| 250 | 1.0 | 450 | 890 | 390 | 350 | 320 | 28 | 3 | 12-23 | 400 | 315 | 62 | 225 | 278 |
| 300 | 1.0 | 500 | 1070 | 440 | 400 | 368 | 28 | 3 | 12-23 | 450 | 398 | 65 | 303 | 330 |
| 350 | 1.0 | 550 | 1320 | 500 | 460 | 428 | 30 | 4 | 16-23 | 550 | 530 | 65 | 351 | 382 |
| 400 | 1.0 | 600 | 1450 | 565 | 515 | 482 | 32 | 4 | 16-25 | 550 | 690 | 65 | 398 | 432 |
| 450 | 1.0 | 650 | 1560 | 615 | 565 | 532 | 32 | 4 | 20-25 | 600 | 870 | 70 | 460 | 485 |
| 500 | 1.0 | 700 | 1720 | 670 | 620 | 585 | 34 | 4 | 20-25 | 650 | 1080 | 78 | 500 | 535 |
| 600 | 1.0 | 800 | 1880 | 780 | 725 | 685 | 36 | 5 | 20-30 | 700 | 1350 | 90 | 600 | 636 |
| 700 | 1.0 | 900 | 2085 | 895 | 840 | 800 | 40 | 5 | 24-30 | 750 | 1950 | 90 | 690 | 726 |
| 800 | 1.0 | 1000 | 2590 | 1010 | 950 | 905 | 44 | 5 | 24-34 | 800 | 2500 | 106 | 790 | 826 |
| 50 | 1.6 | 250 | 345 | 160 | 125 | 100 | 16 | 3 | 4-18 | 250 | 28 | 48 | 49 | 58 |
| 65 | 1.6 | 270 | 395 | 180 | 145 | 120 | 18 | 3 | 4-18 | 250 | 40 | 50 | 64 | 75 |
| 80 | 1.6 | 280 | 425 | 195 | 160 | 135 | 20 | 3 | 8-18 | 300 | 58 | 52 | 78 | 91 |
| 100 | 1.6 | 300 | 510 | 215 | 180 | 155 | 20 | 3 | 8-18 | 300 | 75 | 52 | 96 | 110 |
| 125 | 1.6 | 325 | 570 | 245 | 210 | 185 | 22 | 3 | 8-18 | 350 | 110 | 60 | 120 | 136 |
| 150 | 1.6 | 350 | 725 | 280 | 240 | 210 | 24 | 3 | — | — | — | — | — | — |
Dimensions, pressure ratings, materials, connection type and actuator configuration are subject to the final WDL Valve technical drawing and approved project datasheet.
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