Non Rising Stem Gate Valve — Products & Sub-categories
Non Rising Stem Gate Valve
Non-Rising Stem Gate Valve ensures tight shut-off and smooth operation in high-pressure pipelines.
A Non-Rising Stem (NRS) Gate Valve is designed to shut off or restore flow in a pipeline. The stem stays within the valve body during operation, so there is no upward movement of the stem when the valve is opened. The gate itself moves inside the body to open or close the flow passage.
This design is useful in locations where installation space above the pipeline is limited. NRS gate valves are commonly considered for buried pipelines, valve chambers, pumping stations, irrigation networks, water and wastewater pipelines, and industrial utility services in Egypt.
How Does an NRS Gate Valve Work?
The valve is opened and closed by turning the operating handwheel, cap, gearbox or actuator. As the stem rotates, it moves the gate vertically inside the valve.
With the valve fully open, the gate moves away from the flow path and provides a clear passage through the valve. Turning the operator in the opposite direction lowers the gate onto the seats and stops the flow.
An NRS gate valve is intended for isolation rather than flow control. For normal operation, it is therefore kept either fully open or fully closed.
Main Features
- Non-rising stem arrangement
- Full-bore passage in the open position
- Bi-directional shut-off
- Solid, flexible or resilient wedge construction
- Soft-seated or metal-seated design
- Handwheel, gearbox or actuator operation
- Flanged, threaded or welded connections, depending on design
- Suitable for underground and restricted-height installations
Technical Specifications
| Item | Typical Specification |
|---|---|
| Valve type | Non-Rising Stem Wedge Gate Valve |
| Size | DN40 to DN600 and larger, depending on design |
| Pressure rating | PN10 to PN25 or ASME Class 150 and above, as applicable |
| Wedge | Solid, flexible or resilient |
| Seat arrangement | Soft/Resilient or Metal Seated |
| Operation | Handwheel, operating cap, gearbox, electric or pneumatic actuator |
| Body construction | Cast Iron, Ductile Iron, Carbon Steel or Stainless Steel |
| End connection | Flanged, threaded or butt-weld |
| Face-to-face | EN 558 or ASME B16.10 |
| Flange standard | EN 1092-2, ASME B16.5 or B16.47 |
| Applicable design standards | EN 1074-2, EN 1171, API 600 or API 602, according to valve design |
| Pressure testing | EN 12266 or API 598, as applicable |
Materials
| Component | Material Options |
|---|---|
| Body and bonnet | Cast Iron, Ductile Iron, Carbon Steel, Stainless Steel |
| Gate/Wedge | Ductile Iron, Carbon Steel, Stainless Steel |
| Stem | Stainless Steel, 13Cr, 17-4PH |
| Seat rings | Bronze, Stainless Steel, Hard-Faced Alloy |
| Stem nut | Brass or Bronze |
| Packing | Graphite or PTFE |
| Seals | EPDM or NBR |
| Fasteners | Carbon Steel or Stainless Steel |
Grades
Typical material grades used for NRS gate valve construction include the following, depending on the selected valve design:
| Material | Common Grades |
|---|---|
| Cast Carbon Steel | ASTM A216 WCB / WCC |
| Low-Temperature Carbon Steel | ASTM A352 LCB / LCC |
| Stainless Steel | ASTM A351 CF8 / CF8M / CF3M |
| Duplex Stainless Steel | ASTM A995 4A |
| Cast Iron | ASTM A126 Class B |
| Ductile Iron | ASTM A536 |
| Stem and forged trim | ASTM A182 F6a / F304 / F316 / F316L / 17-4PH |
Soft-Seated or Metal-Seated?
The seating arrangement depends on the service in which the valve will operate.
With a soft-seated NRS gate valve, the sealing surface uses an elastomer such as EPDM or NBR. This type is generally selected when a tight shut-off is required and the service conditions are suitable for the selected elastomer.
A metal-seated NRS gate valve uses metallic seating surfaces, which may include stainless steel, bronze or hard-faced alloys. This construction can be specified for services where the seating surfaces need greater resistance to wear, temperature or harsher operating conditions.
Applications and Inspection
NRS gate valves supplied for projects in Egypt may be used in municipal and transmission pipelines, irrigation systems, wastewater networks, pumping stations, raw-water lines, fire-water systems, industrial utility lines and underground valve chambers.
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