Wafer Check Valve

Product Overview

The Dual Disc Wafer Check Valve (also known as the twin‑plate wafer check valve) is an ultra‑short pattern check valve featuring two semicircular discs that rotate around a common center pin shaft. Each disc is independently mounted and equipped with a torsion spring, ensuring that the discs open under forward flow and close rapidly when flow reverses or stops.

Compared with traditional swing or lift check valves, the dual disc wafer check valve offers significant advantages including extremely short face‑to‑face length (only 1/4 to 1/6 that of flanged swing check valves), light weight, low flow resistance, and reduced water hammer impact. This valve is widely used in water treatment, oil & gas, chemical, power generation, fire protection, HVAC, and industrial recirculating water systems, with pressure ratings from Class 150 to Class 1500 and nominal diameters from DN50 to DN1200 and larger.

Product Structure

The Dual Disc Wafer Check Valve mainly consists of the following parts:

1. Body: Precision cast or forged in ductile iron (QT450‑10), carbon steel (WCB), stainless steel (CF8/CF8M), duplex stainless steel, etc. Wafer design with annular grooves or O‑ring grooves on the sealing faces. Face‑to‑face dimensions conform to ASME B16.10 for wafer dual‑plate check valves.

2. Discs (Twin Discs): Two semicircular discs rotating around a common center pin shaft. Each disc is independently mounted. The sealing faces can be hardfaced with Stellite or covered with rubber/PTFE.

3. Springs: Stainless steel (304/316/17‑4PH) torsion springs – one spring per disc – providing rapid closing force, ensuring the discs seat before reverse pressure builds.

4. Pin Shaft: Stainless steel or Inconel alloy shaft running through the center of the body, supporting both discs.

5. Seat: Metal seat (hardfaced) machined in the body or inserted soft seat (PTFE, PEEK, NBR, EPDM).

6. Stop Pin / Limit Stop: Limits the maximum disc opening angle (typically 75°–85°) to prevent over‑travel.

No bolts pass through the body; the valve is clamped between two pipe flanges, with sealing achieved by flange gaskets or integral O‑rings.

Function

1. Prevents Backflow: Forward flow pushes the two discs open; reverse flow or flow stoppage makes the discs close rapidly under spring force and backpressure, stopping backflow.

2. Ultra‑Short Face‑to‑Face Length: Extremely compact (e.g., DN300 length approx. 100 mm), saving installation space and reducing pipe support costs.

3. Low Flow Resistance: When fully open, the two discs lie nearly parallel to the flow path, providing a low resistance coefficient and significant energy savings.

4. Rapid Closing: Stainless steel torsion springs deliver instantaneous closing force, effectively reducing water hammer peaks.

5. Low Opening Pressure: Optimized spring stiffness, opening pressure typically 0.005–0.02 MPa, resulting in low energy consumption.

6. Independent Disc Action: Each disc rotates independently, maintaining balance even at low flow or asymmetric flow conditions, reducing disc flutter.

7. Multiple Sealing Options: Soft sealing (zero leakage) or metal sealing (high temperature and wear resistance) available.

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Working Conditions

1. Applicable Media: Water, raw water, seawater, sewage, oil, gas, steam, weak acids/alkalis, chemical media, etc.

2. Temperature Range: –29°C to +200°C (soft seated); –29°C to +550°C (metal seated, material dependent).

3. Pressure Rating: Class 150, 300, 600, 900, 1500 (PN16 – PN260).

4. Nominal Diameter: DN50 – DN1200 (2″ – 48″); larger sizes available on request.

5. Installation Position: Horizontal pipeline (recommended); vertical (flow upward) also acceptable. Some designs allow vertical flow downward with specific spring configurations.

6. Typical Applications:

   1. Municipal water supply and wastewater treatment pump discharges

   2. Industrial recirculating cooling water systems

   3. Fire protection pump discharges

   4. Petrochemical plant pump discharges

   5. HVAC systems

   6. Power plant cooling water systems

   7. Seawater intake systems

Summary

The Dual Disc Wafer Check Valve, with its outstanding advantages of ultra‑short face‑to‑face length, lightweight design, dual‑spring rapid closing, and low flow resistance, is one of the most widely used check valve types in both large‑bore and small‑to‑medium‑bore piping systems. It is suitable for ambient temperature low‑pressure applications such as water and sewage, and can be extended to high‑temperature and high‑pressure services by selecting metal seats and alloy materials. Compared with swing check valves, the dual disc wafer type reduces length by over 70% and weight by 50%–80%; compared with lift check valves, it offers lower flow resistance and no installation orientation restrictions (vertical flow upward). Whether in municipal pumping stations, industrial recirculating water, or fire protection systems, the Dual Disc Wafer Check Valve provides reliable, economical, and efficient anti‑backflow protection. For pipeline systems that demand compact design, rapid response, and low maintenance, the Dual Disc Wafer Check Valve is an ideal core component.