Surge Anticipating Valve -- Diaphragm Pilot Cast Iron
Self-Acting Surge Anticipating Valve for Pump Water Hammer Protection
Document No.SV-DS-SRG-001
RevisionRev A
DateMay 2026
ManufacturerSupreme Valves India, Ahmedabad, Gujarat, India
This datasheet covers pilot-operated surge anticipating valves in cast iron for protecting water pipelines from water hammer caused by pump start-up and shut-down.
Technical Specifications
| Parameter | Specification |
|---|
| Size Range | DN50 to DN400 (2" to 16") |
| Pressure Rating | PN10 / PN16 / Class 150 |
| Body Material | Cast iron GG25 or ductile iron GGG50, epoxy coated |
| Trim Material | SS316 plug, seat, and stem |
| Pilot Material | SS316 high-sensitivity diaphragm pilot with EPDM diaphragm |
| Set Pressure | Factory-set to pipeline maximum operating pressure plus 10% margin |
| Temperature Range | 0°C to +80°C (water service) |
| End Connections | Flanged BS EN 1092-1 PN10/16 or ASME B16.5 Class 150 |
| Operation | Self-acting pilot-operated diaphragm; opens on pressure drop anticipation |
| Features | Surge anticipation, slow closing, SS316 trim, EPDM diaphragm, field-adjustable setpoint |
| Response Time | Opens within 0.5 seconds of pilot sensing pressure drop |
Materials of Construction
| Component | Material |
|---|
| Body | GG25 cast iron or GGG50 ductile iron, sand cast, machined seat bore and cover flange, epoxy coated |
| Bonnet / Cover | GG25 or GGG50 bolted cover with pilot mounting boss and spring chamber |
| Plug | SS316 streamlined plug with EPDM resilient seat insert |
| Seat | SS316 replaceable seat ring, retained by snap ring |
| Stem | SS316 guided stem with upper and lower bearings |
| Diaphragm | EPDM fabric-reinforced rolling diaphragm for main valve; EPDM pilot diaphragm |
| Pilot Assembly | SS316 high-sensitivity pilot with adjustable spring, needle valve for closing speed, and strainer |
| 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; surge response witness test |
| Certification | CE, ISO 9001, WRAS on request |
Applicable Standards
| Standard | Description |
|---|
| Design Standard | BS EN 1074-5 / AWWA C508 |
Notes
- Surge anticipating valve must be installed on pump discharge header, upstream of the first high-point or bend in the pipeline.
- Pilot setpoint is factory-calibrated to pipeline MOP plus 10%; field adjustment is required after commissioning to match actual surge profile.
- Discharge from surge valve must be routed to atmosphere or sump with capacity for full pump flow for 5 to 10 seconds during surge event.
- Pilot strainer must be cleaned monthly; debris in pilot causes delayed or failed opening and loss of surge protection.
- For multi-pump stations, install one surge valve per pump or one common valve sized for total station flow.
