Valves and Valve Equipment

Wafer Swing Check Valve: Working Principle, Models and Installation

Learn how single-disc wafer swing check valves installed between flanges work, how spring-assisted and springless models differ and what to watch during installation.

ORFA Technical TeamUpdated: Oct 30, 20264 min read

Wafer swing check valve – single-disc check valve installed between flanges

At pump discharges and at any point where reverse flow could damage equipment, flow must travel in one direction only. A wafer swing check valve is a compact check valve clamped between two pipe flanges, with a single hinged disc that opens with the flow and closes against reverse flow. Being much shorter and lighter than flanged swing check valves makes it a practical choice for water, HVAC and process lines.

This article explains how a wafer swing check valve works, the difference between spring-assisted and springless designs, installation rules and the technical data of the models ORFA supplies.

What Is a Wafer Swing Check Valve?

A swing check valve works with a disc that pivots on a hinge. “Wafer” means that the body has no flanges of its own and is clamped between two pipe flanges with studs, saving both space and weight.

Working Principle

Forward flow: Fluid pressure pushes the disc open.
Open position: With the disc open, the fluid passes through the line.
Flow stops or reverses: As the flow weakens, the disc returns to its seat by spring force on spring-assisted models, or by its own weight and the reverse flow on springless models.
Closed position: Once the disc seats, backflow is prevented.

Spring-Assisted vs Springless

Feature	Spring-assisted	Springless
Closing	The spring closes the disc as soon as flow stops, reducing slam and water hammer	The disc closes by gravity and reverse flow
Pressure loss	Some cracking pressure is needed to overcome the spring	Lower cracking pressure and pressure loss
Installation	Horizontal and vertical (upward flow) lines	Only where the disc can close by gravity (horizontal or vertical upward flow)

Advantages

Backflow protection: Protects pumps and equipment against damage and contamination caused by reverse flow.
Compact design: Much shorter and lighter than flanged swing check valves; fits tight spaces.
Low pressure loss: The single-disc design offers relatively little resistance when open.
Easy installation: Fitted between two existing flanges without separate flange connections.

Models Supplied by ORFA

Model	Body / disc	Seal	Operating temperature	Pressure
Ayvaz ÇV-30 (spring-assisted)	AISI 316 stainless steel / AISI 316	EPDM	-10 °C to approx. +100 °C	PN16
Ayvaz ÇV-33 (springless)	AISI 316 stainless steel	Viton (FKM)	-10 °C to +180 °C	PN16
Ayvaz ÇV-35 (spring-assisted)	Galvanized carbon steel / nickel-plated disc	EPDM	-10 °C to approx. +100 °C	PN16

The models are available in several nominal sizes from DN32 upwards and fit between PN10 and PN16 flanges. Check the product pages for current size options.

Installation Notes

Follow the flow direction arrow on the body.
Check the pipe bore and the adjacent arrangement so that the opening disc does not strike the neighbouring pipe, reducer or another valve.
Avoid installing too close to a pump outlet, elbow or butterfly valve; turbulent flow makes the disc flutter and wear prematurely.
Make sure the seal material suits the medium and temperature; EPDM-seated models are not suitable for steam.

Tip: On lines that suffer water hammer when the pump stops, a spring-assisted model closes the disc before reverse flow builds up and noticeably reduces slam.

Applications

Water, distribution and transmission lines
Pump discharges and pumping stations
Heating, cooling and air-conditioning systems
Shipyards, marine mechanical and cooling systems
Paper, textile, mineral and oil industries

Frequently Asked Questions

What is the difference between a wafer swing check valve and a dual plate check valve?

Both are installed between flanges. A swing check valve has a single hinged disc, while a dual plate check valve has two half discs folding around a central pin, giving a shorter closing stroke.

Can a wafer swing check valve be installed vertically?

Spring-assisted models can be used in horizontal and vertical upward-flow lines. Springless models must be installed where the disc can close under its own weight, i.e. horizontal or vertical upward-flow lines.

Which model is suitable for higher temperatures?

EPDM-seated spring-assisted models are limited to hot-water temperatures. For higher temperatures, check the temperature and pressure limits of models such as the Viton-sealed springless ÇV-33 against the operating conditions.

Conclusion

Wafer swing check valves provide reliable backflow protection with a compact body and low pressure loss. Choosing the spring-assisted or springless version and the right seal material for the operating conditions is the key to long service life. Explore all check valve options in our Check Valves product group.

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