API · ASME · DIN · EN standard industrial valves
Pressure Seal Swing Check Valves
Pressure seal swing check valves use the line pressure itself to load the bonnet gasket, which is why power and high-pressure process plants use them where bolted-bonnet construction would need heavy flanges. The range covers DN65 to DN350 at Class 1500 to Class 2500, with body, disc and hinge in WCB, WC1, WC6 or WC9 and A105/F22 seats on an SS316-plus-graphite gasket. Design follows API 6D and ASME B16.34 with ASME B16.10 face-to-face and B16.5/B16.47/B16.25 connection dimensions. Selection turns on class against the header pressure and the chromium-molybdenum body grade against steam temperature.
Part of the Check Valves family
Last updated: 2026-11
Family specifications
| size range | DN65 to DN350 |
|---|---|
| pressure class | Class 1500 to Class 2500 |
| pressure class | Class1500 to Class2500 |
| body materials | WCB, WC1, WC6, WC9 |
| body materials | A105, F22 |
| disc materials | WCB, WC1, WC6, WC9 |
| seat materials | A105, F22 |
| end connections | Flanged, Butt Weld |
| operation | Self-acting (automatic) |
| temperature range | -196°C to 570°C |
| design standards | API 6D, ASME B16.34 |
| design standards | API6D, ASME B16.34 |
| testing standards | API 598, API 6D, MSS |
| face to face | ASME B16.10 |
| gasket | SS316 + Graphite |
| connection standards | ASME B16.5, ASME B16.47, ASME B16.25 |
| psw service intent | ideal for high pressure steam, liquid, catalytic reformers, and other tough services |
| psw size range | 2 Inch – 36 Inch |
| psw pressure range | ASME Class 600 - 2500 LB |
| psw design standards | API 6D or ASME B16.34 |
| psw testing | API 598 |
| psw flange standard | ASME B16.5, ASME B16.47 (API 605, MSS SP-44) |
| psw bw end standard | ASME B16.25 |
| psw face to face | ASME B16.10 |
| psw nace | NACE 0175 |
| psw materials | ASTM A216 WCB WCC, ASTM A217 WC1, WC6, WC9, ASTM A351 CF8, A351 CF8M, A351 CF3, A351 CF3M, A351 CN7M |
| psw trim | Standard trim is cobalt-chromium hardfacing alloy faced seat and disc seat surfaces |
| psw seat ring options | Welding seat rings or Renewable seat rings |
| psw port options | Full Open and regular port as optional |
| psw orientation | Suitable for Vertical or Horizontal installation |
| flt figure classes | 600# Pressure Seal Swing Check Valves 1661 2-24′′ |
| flt figure class 900 | 900# PRESSURE SEAL SWING CHECK VALVES 1931 2-24′′ |
| flt figure class 1500 | 1500# Pressure Seal Swing Check Valve 1161 2-24′′ |
| flt figure class 2500 | 2500# Pressure Seal Swing Check Valves 1261 2-24′′ |
| flt end connections | Pressure Seal Bonnet Butt Weld Ends |
| flt materials | Cast Carbon, Stainless or Alloy Steel Materials |
| flt trim | Available in all trim configurations |
| wlp range | Swing Check 2" to 24" 600, 900, 1500 & 2500 # RF, RTJ or BW |
| wlp service intent | power generation plants with fossil, coal, thermal, gas, nuclear power plants, steam power stations |
| wlp seal principle | use the pressure line to assist in the seal of the valve with a preloaded metallic or graphite pressure seal gasket placed between body and bonnet |
| wlp gasket | soft carbon steel (silver platted) or stainless steel |
| wlp seat ring | Seat ring is welded to the body to provide tight joint |
| wlp disc overlay | Sealing areas of the disc with cobalt-chromium hardfacing alloy 6 overlay for better operation service |
| wlp damper options | Damper and counterweight options also available as per Customer request. |
| wlp installation orientation | install this valve in a horizontal position only |
| wlp closure speed | Designed to close quickly and quitely. |
| wlp design standard | Design in accordance with ASME B16.34. |
| wlp testing | Test in accordance with API-598. |
| wlp bom cf8m | BODY ASTM A351 GR. CF8M, BONNET ASTM A-351 GR. CF8M, GASKET ASTM A-182 GR. F316, SWING TYPE DISC ASTM A-351 GR. CF8M Co-Cr-W OVERLAY, HINGE PIN ASTM A276 GR 316 |
| vln cover design | The light-weight pressure seal cover remains tight regardless of pressure-temperature fluctuations. |
| vln cage unit | unique compact cage unit design comprised of all moving parts easily accessible for service |
| vln hinge pin | Eliminates pin seal leakage and provides in-line service. |
| vln hinge bearings | A sturdy disc hinge moves on four cobalt-chromium hardfacing alloy bearings, supporting the hinge pin and preventing binding. |
| vln seat finish | Forged disc/seat are Stellited, ground and lapped to a mirror finish for maximum erosion resistance and long service life. Seat rings are seal-welded to the body. |
| vln gasket standard | Standard in valves to ASME Class 2500 |
| vln product scope | pressure seal and bolted bonnet swing, tilting disc and piston check valves |
| lnt swing range | 2" to 28" -- Class 600, 2" to 28" 2" to 24" Class 900, 2" to 28" 2" to 24" Class 1500, 2" to 28" 2" to 24" Class 2500 |
| lnt operating principle | Pressure Seal Check Valves automatically open by velocity of medium and close by the gravitational force when the flow reverses or stops. |
| lnt disc types | 1) Swing type 2) Tilting Disc type |
| lnt installation | install swing check valves at a distance equal to 10 times or more the pipe diameter from the upstream elbows for better performance |
| lnt seal principle | internal fluid pressure-force on the bonnet increases the compressive loading on the sealing gasket |
| lnt bonnet context | Pressure seal bonnet valves are a compact alternative to bolted bonnets, especially for high pressure applications. |
| hinge materials | WCB, WC1, WC6, WC9 |
| washer materials | F316 |
| sealing ring | Mild Stainless Steel |
| connection dimensions | ASME B16.5, ASME B16.47, ASME B16.25 |
Ordering & documentation
Documents
Ask for the documentation set with the inquiry — typical items (material certificates, test reports to the listed inspection standard, dimensional drawings) are confirmed and supplied with the quotation.
Quotation
Send the medium, temperature, pressure, size and connection for a quotation-ready inquiry. Lead time, MOQ and price are confirmed at quotation, together with the documents to be supplied with the order.
Sample & supply
Supply terms, order quantities and lead time are agreed per order — state the destination country and required schedule with the inquiry.
Storage & shipping
Store valves with seats and seals protected from UV, ozone and deformation, and keep end-face protectors on until installation; storage limits and shipping arrangements for the selected materials are confirmed at quotation.
Frequently asked questions
What standards govern the design and testing of pressure seal swing check valves?
The published specification for this family lists API 6D, ASME B16.34 as the design standards. Testing follows API 598, API 6D, MSS.
What sizes and pressure ratings are available for pressure seal swing check valves?
The published size range is DN65 to DN350, and the published pressure ratings are Class 1500 to Class 2500. Availability of a specific size and rating is confirmed at quotation.
What materials are pressure seal swing check valves available in?
The published specification lists body materials: WCB, WC1, WC6, WC9. Material availability for a specific size and rating is confirmed at quotation.
What working temperature range do pressure seal swing check valves cover?
The published working temperature range is -196°C to 570°C. For a medium at the edge of the range, confirm the suitability of the selected seat and body materials at quotation.
What end connections do pressure seal swing check valves support?
The published specification lists Flanged, Butt Weld as the available end connections. The connection for a specific size is confirmed at quotation.
What should a quotation inquiry for pressure seal swing check valves include?
The governing standard and class, nominal size, body and seat materials, the service medium with temperature, and the destination — anything missing is confirmed during quotation.
Request a quote for pressure seal swing check valves
Submit the requirement here — a quotation-ready inquiry states the governing standard and class, size, materials, medium, temperature and destination.
What happens to your details is described in our privacy notice.
Get a quotation for Pressure Seal Swing Check Valves
Send the standard, pressure class and size for a quotation-ready inquiry — answered with documents and terms.