Soft seal gate valve

Product Overview

The Non‑rising Stem Resilient Seated Gate Valve is a soft‑sealing gate valve with a non‑rising stem and a fully rubber‑encapsulated gate. It is widely used in water supply, sewage, fire protection, building water supply & drainage, and industrial recirculating water systems. Compared with rising stem gate valves, the non‑rising stem design requires less installation height, making it ideal for confined spaces such as valve pits or trenches. Compared with metal‑seated gate valves, the resilient seated design provides zero leakage, excellent corrosion resistance, no rusting, and easy operation.

The valve features a full‑bore design for minimal flow resistance. The gate is fully encapsulated with EPDM or NBR rubber, forming a reliable elastic seal against the seat in the body. The valve has flanged connections, with nominal diameters from DN40 to DN600, pressure ratings PN10/PN16 (Class 125/150), and is widely used in municipal water supply & drainage, building services, and agricultural irrigation.

Product Structure

The Non‑rising Stem Resilient Seated Gate Valve mainly consists of the following parts:

1. Body: Ductile iron (QT450‑10) cast body, coated inside and outside with fusion‑bonded epoxy resin – corrosion resistant and non‑toxic. Flanged ends conforming to GB/T 17241.6, ANSI B16.1, EN 1092‑2, etc. Full‑bore flow path.

2. Gate: Ductile iron core fully encapsulated with rubber (EPDM, NBR, or natural rubber). The rubber is vulcanized to the core with no voids or delamination. The gate sealing face is rubber, which mates with the seat in the body.

3. Seat: Integral seat machined directly in the body (no separate metal seal ring), forming an elastic sealing pair with the encapsulated gate.

4. Stem: Stainless steel (2Cr13, 304, or 316) stem with trapezoidal threads. The lower end connects to the gate, and the upper end engages with the operating nut. The stem does not rise; it only rotates, lifting and lowering the gate.

5. Bonnet: Ductile iron bonnet bolted to the body. Internal guide ribs ensure vertical gate movement.

6. O‑Rings / Packing: Three O‑ring rubber seals (NBR/EPDM) between the stem and bonnet, replacing traditional packing for reliable, maintenance‑free sealing.

7. Drive Nut (Operating Nut): Copper alloy or stainless steel nut that engages with the stem threads, converting rotary motion into linear movement of the gate.

8. Handwheel: Cast iron or ductile iron handwheel directly driving the drive nut. Bevel gear operation is optional for large sizes.

Compact construction; the non‑rising stem design keeps the overall height low, suitable for space‑limited installations.

Function

1. Media Shut‑Off: Rotating the handwheel turns the stem, which drives the gate up or down via the thread pair, opening or closing the valve. Fully open, the gate is completely out of the flow path, providing near‑zero flow resistance.

2. Zero Leakage Sealing: The gate is fully encapsulated with resilient rubber. When closed, it presses tightly against the body seat, achieving bidirectional zero leakage (meets ISO 5208 Rate A zero leakage).

3. Corrosion Resistance: The body is coated with epoxy resin inside and out, the gate is rubber‑encapsulated, and the stem is stainless steel. All wetted parts are corrosion resistant, suitable for water, sewage, seawater, etc.

4. Easy Operation: Low friction between rubber and metal, plus self‑lubricating stem threads, result in low operating torque and easy manual operation.

5. Non‑rising Stem Design: During valve operation, the stem rotates without rising, so the overall height does not change. Ideal for valve pits, basements, and other confined spaces.

6. Maintenance‑Free: Stem sealing uses three O‑rings, requiring no packing adjustment. Long‑term leakage‑free performance with no maintenance.

7. Full‑Bore Flow Path: When fully open, the bore has no restriction, providing minimal pressure loss and significant energy savings.

Working Conditions

1. Applicable Media: Clean water, raw water, sewage, seawater, fire water, irrigation water, mild acids/alkalis (with appropriate rubber).

2. Temperature Range: 0°C to +80°C (standard EPDM); –10°C to +60°C (NBR).

3. Pressure Rating: PN10, PN16 (Class 125, Class 150).

4. Nominal Diameter: DN40 – DN600 (1.5″ – 24″); larger sizes available on request.

5. Installation Position: Horizontal or vertical (stem upward), vertical installation recommended.

6. Typical Applications:

   1. Municipal drinking water supply networks

   2. Building water supply and drainage systems

   3. Wastewater treatment plant inlet/outlet valves

   4. Fire pump discharges and fire protection networks

   5. Agricultural irrigation pumping stations

   6. Industrial recirculating cooling water systems

   7. Seawater intake pipelines

Summary

The Non‑rising Stem Resilient Seated Gate Valve, with its advantages of compact non‑rising stem construction, full‑bore low flow resistance, resilient rubber zero‑leakage sealing, and corrosion‑resistant maintenance‑free design, is one of the most commonly used shut‑off valves in water supply & drainage, fire protection, building services, and industrial water systems.

Compared with rising stem gate valves, the non‑rising stem design maintains a constant overall height, making it ideal for valve pits, basements, and other confined spaces. Compared with metal‑seated gate valves, the resilient rubber seal provides absolute zero leakage, lower operating torque, and better corrosion resistance. The valve features a ductile iron body with epoxy coating, a fully rubber‑encapsulated gate, and a stainless steel stem – all wetted parts are corrosion resistant, especially suitable for water and sewage services. For pipeline systems that demand reliable shut‑off, space‑limited installation, and maintenance‑free operation, the Non‑rising Stem Resilient Seated Gate Valve is an ideal choice.