Non Rising Stem Gate Valve

A Non-Rising Stem Gate Valve Suppliers In South Africa supplies valves 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 Gate Valve
Size Range	DN40–DN600 and larger
Pressure Rating	PN10–PN25 / ASME Class 150 and above
Wedge	Solid / Flexible / Resilient
Seat Arrangement	Resilient / Metal Seated
Body & Bonnet	ASTM A126 Class B / ASTM A536 / ASTM A216 WCB, WCC / ASTM A351 CF8, CF8M, CF3M / ASTM A995 4A
Gate / Wedge	Ductile Iron / Carbon Steel / Stainless Steel
Operation	Handwheel / Operating Cap / Gearbox / Electric / Pneumatic
End Connection	Flanged / Threaded / Butt Weld

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 South Africa 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.