API · ASME · DIN · EN standard industrial valves
Double-Seated Control Valves
Double-seated control valves balance the fluid pressure across two plugs in opposition, so the actuator works against a fraction of the unbalanced force of a single seat — the choice for large pressure drops and bigger sizes where a single-seat plug would need an impractical actuator, traded against softer metal-seal shutoff because thermal expansion keeps one seat imperfect. The range covers DN20 to DN300 at PN16 to PN100 / Class 150 to Class 600 in water, oil, steam and gas from -196℃ to 450℃, with WCB/LCB/CF8/CF3/CF8M/CF3M bodies, balanced double-seat spools in straight-through cast globe bodies, flanged (FF/RF/MF/RTJ to IEC 60534) or SW/BW welded connections, linear, equal-percentage and quick-open trim, five bonnet executions (standard to 230℃, radiator-type above 230℃, extended low-temperature to -196℃, bellows-seal and hot-jacket), V-PTFE or flexible-graphite packing, metal-graphite gaskets, and multi-spring diaphragm or piston pneumatic actuators, with per-PN face-to-face and height tables from DN25 to DN300. Selection turns on the pressure drop the balanced trim must absorb, the bonnet execution against line temperature, and the leakage class the service tolerates.
Part of the Control Valves family
Last updated: 2026-11
Family specifications
| size range | DN 20 to DN 300 |
|---|---|
| pressure class | PN16 to PN100, Class 150 to Class 600 |
| flow characteristics | Linear, Equal percentage, Quick open |
| body materials | WCB, LCB, CF8, CF3, CF8M, CF3M |
| end connections | Flanged, Butt weld |
| operation | Pneumatic: multi-spring diaphragm actuator, piston type actuator |
| temperature range | -196℃ to 450℃ |
| media | Water, Oil, Steam, Gas |
| body type | Straight through casting globe type |
| spool type | Balanced double seated type |
| flange standard | IEC 60534 |
| bonnet types | Standard type (-20℃ to 230℃), Radiator type (-45℃, above 230℃), Low temperature extended type (-196℃ to -45℃), Bellow seal type, Warm insulation Jacket type |
| packing | V type PFTE packing, flex. graphite packing |
| gasket | Metal graphite packing |
| wDs size range | 3/4-16 Inch, DN20-DN400 |
| wDs pressure class | 150-600 LB, PN20-PN100 |
| wDs body materials | ASTM A216 WCB, ASTM A217 WC6, ASTM A352 LCB, ASTM A351 CF8, ASTM A351 CF8M, ASTM A351 CF3M, ASTM A351 CF3 |
| wDs temperature range | -196 - +550°C |
| wDs end connections | Flanged End, Welded End, Threaded End |
| lDs product name | Double Seated Pneumatic Control Valve |
| lDs action type | Air-to-open, Air-to-close |
| lDs size range | DN25-DN300 (1 Inch-12 Inch) |
| lDs pressure class | PN16, PN25, PN40, PN64 (Class 150LB, 300LB, 400LB) |
| lDs connection method | Flanged type (welding can be customized) |
| lDs plug type | Double seated contoured plug |
| lDs flow characteristics | Equal percentage, linear |
| mDs body materials | Stainless Steel, Carbon Steel |
| mDs bonnet materials | Carbon Steel, Stainless Steel |
| mDs plug materials | SS304, SS316, cobalt-chromium hardfacing alloy |
| mDs gasket material | Stainless Steel |
| mDs nominal diameter | DN25 to DN300 |
| mDs nominal pressure | PN16 to PN64, Class150 to Class2500 |
| mDs end connections | Flanged, Socketweld, Buttweld |
| mDs actuation type | Double Acting, Spring Return |
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 sizes and pressure ratings are available for double-seated control valves?
The published size range is DN 20 to DN 300, and the published pressure ratings are PN16 to PN100, Class 150 to Class 600. Availability of a specific size and rating is confirmed at quotation.
What materials are double-seated control valves available in?
The published specification lists body materials: WCB, LCB, CF8, CF3, CF8M, CF3M. Material availability for a specific size and rating is confirmed at quotation.
What working temperature range do double-seated control valves cover?
The published working temperature range is -196℃ to 450℃. 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 double-seated control 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 double-seated control 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 double-seated control valves
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Get a quotation for Double-Seated Control Valves
Send the standard, pressure class and size for a quotation-ready inquiry — answered with documents and terms.