Pressure Reducing Valve -- Direct Acting Diaphragm Ductile Iron
Self-Acting Downstream Pressure Reducing Valve for Water Distribution
Document No.SV-DS-PRV-002
RevisionRev A
DateMay 2026
ManufacturerSupreme Valves India, Ahmedabad, Gujarat, India
This datasheet covers direct-acting diaphragm pressure reducing valves in ductile iron for maintaining constant downstream pressure in water distribution, building services, irrigation, and industrial feedwater systems.
Technical Specifications
| Parameter | Specification |
|---|
| Size Range | DN20 to DN300 (3/4" to 12") |
| 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 | 1 to 10 bar downstream (standard); higher on request |
| Temperature Range | 0°C to +80°C (EPDM) / +120°C (NBR) |
| End Connections | Screwed NPT/BSP (small sizes); 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 | Downstream sensing, direct acting, EPDM diaphragm, SS316 trim, slow opening, anti-cavitation |
| Accuracy | ± 0.2 bar from set pressure across 10:1 flow turndown |
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 downstream pressure sensing port 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 |
| Stem | SS316 guided stem with upper and lower bearings |
| Diaphragm | EPDM or NBR fabric-reinforced rolling diaphragm, nylon fabric reinforced |
| Spring | Music wire compression spring, factory-set, 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 reducing valve must be sized for maximum flow demand at minimum differential; undersizing causes hunting and pressure oscillation.
- Downstream pressure sensing line must be taken from straight pipe at least 5 diameters downstream of valve; avoid bends and tees near sensing point.
- For high-differential service (>5 bar reduction), specify anti-cavitation trim or parallel low-flow bypass valve to prevent noise and erosion.
- Spring range must be selected to cover actual set pressure; do not operate at extreme ends of spring range where control accuracy degrades.
- Install isolation valves upstream and downstream and a bypass line for maintenance; never isolate valve without alternate flow path.
