Non-Rising Stem Gate Valve
Non-Rising Stem · DN40–DN300 · PN16 · For Buried Service
The non-rising stem gate valve keeps its stem inside the body, so it fits in shallow trenches and wall boxes where a rising stem would hit the cover.
A position indicator on the handwheel still shows open/closed for buried water and irrigation mains.
Key Features
Tight Isolation
Wedge-to-seat geometry gives reliable shutoff with minimal leakage.
Low Pressure Loss
Straight-through bore keeps pressure drop near zero in open position.
Rising / Non-Rising Stem
OS&Y rising stem shows open/closed at a glance; NRS suits buried service.
Resilient or Metal Seat
EPDM/NBR for water; SS316/Stellite for steam and slurry.
Bi-Directional
Wedge disc seals in both flow directions for flexible installation.
Actuator Ready
Top flange accepts gearbox, pneumatic or electric actuators.
Technical Specifications
| Parameter | Specification |
|---|---|
| Body Material | WCB / SS304 / SS316 / Ductile Iron GGG50 |
| Wedge / Disc | Solid Wedge / Flexible Wedge / Parallel Slide |
| Seat Material | Resilient (EPDM / NBR) / Metal (SS316 / Stellite) |
| Size Range | DN40 – DN1200 (1.5" – 48") |
| Pressure Rating | PN10 / PN16 (ANSI 150 / 300) |
| End Connection | Flanged (ISO 7005-2 / ASME B16.5) / Butt-Weld |
| Stem Type | Rising Stem (OS&Y) / Non-Rising Stem |
| Operation | Handwheel / Gearbox / Pneumatic / Electric |
| Temperature | Resilient: -10→+80°C ; Metal: -40→+425°C |
| Leakage | Tight shutoff, bubble-tight with resilient seat |
| Standards | Design reference: API 600 / GB/T 12234 / EN 1171 — no API monogram held (API 609 applies to butterfly valves, not gate valves) |
| Certification | ISO 9001:2015, MTC available |
How to Specify a How to Specify a Non-Rising Stem Gate Valve
A non-rising stem gate valve keeps the stem height constant, which is why it is the default for underground and confined installations. What it gives up is visible position.
Choose it for limited headroom or buried service
The stem turns without travelling, so no vertical clearance is needed above the handwheel and a valve box only has to reach the operating nut.
It cannot show position by itself
There is no rising stem to read. If the system needs visible indication, either use a rising stem valve or fit a separate position indicator.
Count the turns to know the travel
On a non-rising stem valve the only indication of position is the number of turns from the stop. Record that number on commissioning and put it on a tag.
It suits direct-buried water networks
This is the standard configuration for water distribution valve boxes, where a rising stem would need an unnecessarily tall box.
Same body, same seat — only the stem differs
Because it is the same valve underneath, the seat and trim choices follow the same rules as the equivalent rising-stem version.
Installation & Maintenance
Set the valve box over the operating nut
The box has to line up with the nut after backfilling. Set it before backfilling and check the key engages.
Do not shorten the stem
A cut stem changes the travel and invalidates the position count. Use the extension length supplied for the depth.
Exercise it annually and log the turns
With no visual indication, the turn count is your only evidence the valve is working.
Check the packing gland in wet pits
A buried non-rising stem relies on the packing. Inspect it whenever the box is opened.
Common Specification Mistakes
Expecting visual position indication
There is none. Use a rising stem valve or a separate indicator.
Losing the turn-count record
Without it nobody knows whether the valve is open or closed.
Cutting the stem to fit a shallow box
Changes the travel and defeats the position count.
Frequently Asked Questions
When should I use a rising-stem (OS&Y) gate valve?
Use OS&Y where you need visual confirmation of open/closed position — typical for fire protection and above-ground piping. Non-rising stem suits buried or space-limited installs.
Resilient seated or metal seated?
Resilient (EPDM/NBR) seats give bubble-tight shutoff for clean water up to +80°C. Metal seats handle steam, slurry and temperatures up to +425°C.
Why choose a knife gate valve?
Knife gate valves have a sharpened disc that cuts through slurry, pulp and viscous media — ideal for mining, wastewater and bulk solids.
Applications & Use Cases
Water & Wastewater
Resilient-seated gate valves for mains, hydrants and treatment plants.
Fire Protection
OS&Y gate valves for sprinkler and hydrant systems.
Power & Steam
Metal-seated wedge gates for high-temperature steam lines.
Mining & Slurry
Knife gate valves for abrasive and viscous process streams.
