BS 5163 NRS Resilient Gate Valves for Waterworks

SJZ Metalsin supplies BS 5163 non-rising stem (NRS) resilient seat gate valves for the underground use in waterworks. The body and bonnet of these valves are usually made from ductile (spheroidal graphite) cast iron or grey (flake graphite) cast iron. They may be operated by a handwheel, a stem cap to engage with standard operation keys, or an actuator. The exterior and interior surfaces of the valve shall be fusion bonded epoxy coated in accordance with AWWA C550, usually in blue color RAL 5005. BS 5163 NRS resilient gate valves shall be furnished with flanged ends, the dimensions of which are usually in accordance with EN1092-2, BS 4504, or BS 4772, etc.

Non-Rising Stem & Resilient Wedge

A non-rising stem (NRS) gate valve designed to BS 5163 standards is characterized by a stem that remains in a fixed vertical position when the valve is operated. Instead of the stem moving up or down, the gate moves along the stem to open or close the valve. This design is particularly useful in situations with limited vertical space since it doesn’t require extra room for stem movement. The NRS design also helps protect the stem threads from external contaminants, reducing maintenance needs and enhancing valve durability.

Figure-1: photos of BS 5163 NRS resilient seat gate valves: handwheel operated & stem cap operated; FBE coated in blue.

The resilient seat in BS 5163 gate valves is essential for ensuring a reliable and watertight seal, achieved through a ductile iron wedge fully encapsulated by vulcanized rubber EPDM. This design allows the valve to conform to minor irregularities, preventing leaks and enhancing durability. The resilient seat reduces maintenance needs and improves flow efficiency, making these valves ideal for underground installations, municipal water supply systems, and fire protection networks. This feature ensures the valve’s longevity and reliable performance in controlling and isolating water flow in diverse waterworks applications.

Valve Types & Design Working Pressures

Figure-2: A typical drawing for BS 5163 NRS resilient seated gate valves, handwheel operated, flanged ends.

BS 5163 NRS gate valves shall be one of the following types: (a) Type A, which is for T-key operation; (b) Type B, which is for key/bar operation, but which can be operated by a T-key. However, both types shall be capable of operation by a handwheel or actuator. Moreover, Type B valves are designed for heavier duty than Type A valves and will withstand higher torque loads and bending moments. The range of BS 5163 NRS gate valve sizes covered is DN50 to DN600 for nominal pressures of PN10, PN16 and PN25. These valves shall be designed for maximum permissible working pressures at ambient temperatures of one of the following: (a) 10 bar for PN10 valves; (b) 16 bar for PN16 valves; (c) 25 bar for PN25 valves.

Valves Parts & Basic Dimensions