Pressure Sustaining Valve -- Direct Acting Diaphragm Ductile Iron
Self-Acting Upstream Pressure Sustaining Valve for Water and Pump Systems
Document No.SV-DS-PRV-001
RevisionRev A
DateMay 2026
ManufacturerSupreme Valves India, Ahmedabad, Gujarat, India
This datasheet covers direct-acting diaphragm pressure sustaining valves in ductile iron for maintaining minimum upstream pressure in pump suction, tank inlet, and zone boundary water systems.
Technical Specifications
| Parameter | Specification |
|---|
| Size Range | DN50 to DN400 (2" to 16") |
| Pressure Rating | PN10 / PN16 / Class 150 |
| Body Material | Ductile iron GGG50, epoxy coated inside and out |
| Trim Material | SS316 plug, seat, and stem |
| Diaphragm Material | Reinforced EPDM or NBR fabric-reinforced diaphragm |
| Set Pressure Range | 0.5 to 10 bar (standard); higher on request |
| Temperature Range | 0°C to +80°C (EPDM) / +120°C (NBR) |
| End Connections | Flanged BS EN 1092-1 PN10/16 or ASME B16.5 Class 150 |
| Operation | Self-acting direct-acting diaphragm; no power or air required |
| Features | Direct acting, upstream sensing, EPDM diaphragm, SS316 trim, slow opening, anti-cavitation |
| Response | Proportional throttling; maintains set pressure within ± 0.2 bar |
Materials of Construction
| Component | Material |
|---|
| Body | GGG50 ductile iron, sand cast, machined seat bore and diaphragm chamber, epoxy coated |
| Bonnet / Cover | GGG50 bolted cover with diaphragm retention and spring chamber |
| Plug | SS316 streamlined plug with EPDM or NBR resilient seat insert for tight shutoff |
| Seat | SS316 replaceable seat ring, retained by snap ring or threaded collar |
| Stem | SS316 guided stem with upper and lower bearings to prevent plug vibration |
| Diaphragm | EPDM or NBR fabric-reinforced rolling diaphragm, moulded with nylon fabric reinforcement |
| Spring | Music wire compression spring, factory-set to calibration pressure, field-adjustable within range |
| Gaskets | EPDM rubber gaskets for body/cover and diaphragm retention |
Testing & Inspection
| Test | Requirement |
|---|
| Test Standard | Hydrostatic shell and seat test per BS EN 12266-1 |
| Certification | CE, ISO 9001, WRAS on request |
Applicable Standards
| Standard | Description |
|---|
| Design Standard | BS EN 1074-1 / AWWA C508 |
Notes
- Pressure sustaining valve must be sized for maximum flow at minimum differential to avoid undersizing and excessive throttling noise.
- Set pressure spring is factory-calibrated; field adjustment is possible within the spring range using the adjustment screw on the cover.
- For high-differential or cavitation-prone service, specify anti-cavitation cylinder or multi-hole cage trim to prevent erosion damage.
- Diaphragm material must be selected for water temperature and chemistry; EPDM for cold water, NBR for oil-contaminated or higher temperature water.
- Install pressure gauge on upstream sensing line to monitor actual upstream pressure; sensing line must remain clear and undamped.
