Rising Stem Gate Valve — Products & Sub-categories
Rising Stem Gate Valve
Rising Stem Gate Valve ensures reliable shut-off with smooth rising stem operation.
A Rising Stem Gate Valve is used when a pipeline needs to be completely opened or shut off. The stem rises as the valve is opened and moves down when it is closed. Because the stem remains visible above the bonnet, an operator can see the valve position during operation without having to rely only on the handwheel.
This type of gate valve is used across industrial and utility systems in South Africa, including water infrastructure, mining, power plants, oil and gas facilities and general process services.
Key Features
- Visible Stem Position: The rising stem gives a clear indication of whether the valve is open or closed.
- Wedge Gate: The gate moves between the seats to stop the flow when the valve is closed.
- Full Flow Passage: When fully open, the gate is lifted out of the flow path.
- OS&Y Construction: The stem and yoke remain outside the valve body for easy access.
- Two-Way Isolation: The valve can be used to isolate flow in either direction.
- Flexible Operation: Available with a handwheel for manual operation or with a gearbox or actuator for larger or remotely operated valves.
Technical Specifications
| Parameter | Typical Specification |
|---|---|
| Valve Type | Rising Stem Wedge Gate Valve |
| Stem Design | Rising Stem / Outside Screw & Yoke (OS&Y) |
| Size | DN40 and above, depending on valve design |
| Pressure Rating | Selected according to service and design |
| Gate | Solid / Flexible / Resilient Wedge |
| Seating | Soft Seated / Metal Seated |
| Operation | Handwheel / Gearbox / Electric or Pneumatic Actuator |
| End Connection | Flanged / Threaded / Butt-Weld |
| Face-to-Face | EN 558 / ASME B16.10, where applicable |
| Testing | EN 12266 / API 598, where applicable |
Materials & Components
The valve body and bonnet are selected to suit the pressure and service conditions. For water and utility lines, cast iron and ductile iron are commonly used. Carbon steel and stainless steel are available when the application calls for different pressure, temperature or corrosion-resistance requirements.
- Body & Bonnet: Cast Iron / Ductile Iron / Carbon Steel / Stainless Steel
- Gate: Ductile Iron / Carbon Steel / Stainless Steel
- Stem: Stainless Steel / 13Cr / 17-4PH
- Seat Rings: Bronze / Stainless Steel / Hard-Faced Alloy
- Stem Nut: Brass / Bronze
- Packing: Graphite / PTFE
- Gaskets & Seals: EPDM / NBR
- Handwheel: Cast Iron / Ductile Iron
- Fasteners: Carbon Steel / Stainless Steel
Soft-Seated or Metal-Seated?
The seating material is chosen according to the service rather than simply the valve size.
A soft-seated rising stem gate valve uses an elastomeric sealing material such as EPDM or NBR. It is used where tight shut-off is required and the selected elastomer is compatible with the fluid and operating conditions.
A metal-seated valve has metallic seating surfaces, which may be stainless steel, bronze or hard-faced alloy. This arrangement is considered where the seats need to withstand higher temperatures, wear or more demanding service conditions.
Applications in South Africa
Rising stem gate valves can be found in mining and mineral-processing plants, water and wastewater systems, power-generation facilities, petrochemical plants, oil and gas installations and industrial utility lines.
The external stem also makes routine inspection easier. During maintenance, the position of the stem provides a quick visual reference before the valve is operated.
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