What is a wafer check valve?
A wafer check valve is a type of check valve that has a butterfly or wafer-type disk used to open and close fluid flow. A wafer check valve has two ports that is the inlet and outlet port. The valve opens when the inlet side pressure becomes more than the cracking pressure. When the inlet side pressure becomes less, the disk is forced to shut the wafer check valve. Wafer check valve manufacturers design these valves with compact and slim bodies. Despite the body being slim, it is made of strong metallic materials such as stainless steel, ductile iron, cast iron, and carbon steel to make the valve very strong enough to withstand high pressure and high temperature. Wafer check valves are lightweight and are used in different industrial applications. These valves are economical and they are available in different sizes, different flow rates, and different materials to best suit different applications. Wafer check valve manufacturers design these valves with flanges for connecting them to the pipes. The flanged ends have holes where bolts are inserted for connection with the pipeline. The use of bolts and nuts to connect the valve and pipeline ensures that there is no leakage between the valve and pipe joint. By using a wafer check valve, it is easier to access internal parts of the valve for repair and maintenance as well as cleaning.
Figure: wafer check valve.
Components of a wafer check valve
This is the component of a wafer check valve that is used to house all internal parts of the valve. The body is made of strong metallic material so that it can have high strength to withstand fluid pressure and also protect the valve against impact damage from falling objects. The body has the flanged ends with holes used to connect the wafer check valve to the pipe. The ports on a wafer check valve are also made on the valve body.
This is the component of a wafer check valve that is used to open and close the valve. The disc is hinged at one end and the other end is free so that when fluid comes at high pressure it lifts up allowing fluid to flow through the valve. When the pressure is reduced, the disc goes back to its position where it completely closes fluid flow.
This is the part of a wafer check valve where the disk rests. The seat also is used to prevent fluid leakage between the disc and the valve body.
Springs are used in wafer check valves to assist the valve in closing and preventing reverse fluid flow.
Figure: Components of a wafer check valve.
How does a wafer check valve work?
Wafer check valves operate by using a disc. The disc is tasked to opening and closing the fluid flow through the valve. To open the wafer check valve, fluid flowing at high pressure lifts the disc and opens the valve for fluid to flow. As such, fluid keeps flowing through the wafer check valve until the fluid pressure reduces or the device like the pump transporting the fluid is turned off. Immediately the fluid attempts to reverse flow direction and the valve disc moves to its closing position blocking fluid from flowing backward. Wafer check valve manufacturers design these valves for use in pure fluids and fluids with debris or solid particles. These valves rarely clog despite being slim. Wafer check valves are mounted either horizontally or vertically provided the back pressure needed to seat the valve is enough.
Figure: Working of a wafer check valve.
Types of wafer check valve
Stainless steel wafer check valve
This is a wafer check valve that is made of stainless steel material. Wafer check valve manufacturers use the stainless steel material to make this valve to take advantage of the superb properties associated with stainless steel material. A stainless steel wafer check valve is resistant to corrosion and rust. This valve can be used for high-temperature applications since its stainless steel material has a high melting temperature of around 1400 oC. Stainless steel wafer check valves have high strength which makes these valves suitable for use in high-pressure applications and resistant to impact damage that may result from falling objects. The challenge associated with stainless steel wafer check valves is that they are expensive relative to other wafer check valves like plastic ones.
Figure: Stainless steel wafer check valve.
Brass wafer check valve
This is a type of wafer check valve that is made of brass material. Brass wafer check valves are cheaper relative to the stainless steel wafer check valves. However, brass valves have lower operating temperatures relative to stainless steel wafer check valves. Brass wafer check valves are alternative to stainless steel counterparts. Brass material produce strong valve bodies suitable for high pressure and high temperatures of around 200 oC. They are also strong enough to resist impact damage from falling objects. Brass wafer check valves are highly resistant to corrosion, they are malleable and last long. The property of malleability makes it easier to machine the valve parts which reduces the cost of manufacturing the valve. Brass wafer check valves are easily distinguished from other valves by their golden yellowing color as shown below.
Figure: Brass wafer check valve.
PVC wafer check valve
This is a wafer check valve that is made of PVC material. Wafer check valve manufacturers design these valves for use in low-temperature and low-pressure applications. PVC wafer check valves are cheaper relative to the stainless steel and brass types. The PVC wafer check valves are easier to produce and consumes less energy during manufacturing relative to brass and stainless steel wafer check valves. PVC wafer check valves have excellent corrosion resistance compared to stainless steel and brass wafer check valves. Wafer check valve manufacturers recommend these valves for use in an applications where maximum temperature does not go above 60 oC. Above this temperature limit of 60 oC, the PVC material will be distorted and thus the wafer check valve will be damaged. PVC material produces a wafer check valve that is less rigid and of high impact strength suitable for resisting impact damage from falling objects.
Figure: PVC wafer check valve.
Factors considered when selecting a wafer check valve
Material of the wafer check valve
The type of material used to make the wafer check valve determines where that valve can be used. To easily know the right wafer check valve based on the construction material, determine the operating temperature and pressure of the fluid to be controlled. PVC wafer check valves manufacturers produce these valves for use in low temperatures of up to 60 oC. Metallic wafer check valves can withstand high temperatures above 60 oC. If the temperature is very high such as 400 oC, stainless steel material will work better than brass material. Also, PVC wafer check valves are far better resistant to corrosion relative to stainless steel and brass.
The wafer check valve should be able to handle the fluid flow rate and pressure. So, before purchasing the valve, the wafer check valve manufacturer would like to know the pressure, flow rate, and temperature of the fluid for which the valve is needed. High fluid pressure can cause leakages and thus damage and injuries.
The wafer check valve used should be as much as possible be free from blockage. The frequent blockage will stop production and will come at a cost of repair and maintenance. So the wafer check valve used should be considered for applications properties like the type of media and if it contains slurries.
This includes features such as cracking pressure, horizontal versus vertical installation, response time, normally open versus normally closed, the direction of flow that is downwards or upwards, and density of the fluid.
Applications of wafer check valves
- Wafer check valves are used in the foods and beverages industries.
- They are used in commercial water supply systems.
- Wafer check valves are used in processing chemicals.
- They are used in swimming pools
- These valves are used to control the direction of water flow in household tanks.
- Wafer check valves are used in the oil and gas industries.
- They are used in irrigation systems.
Advantages of wafer check valves
- Wafer check valves are light in weight relative to other valves like globe valves.
- These valves are small in size relative to other valves like gate valves.
- Wafer check valves have low-pressure drop which improves the valve’s efficiency.
- These valves are automatic thus saving on the cost of valve actuator or valve operator often found in other valves like gate valves.
- Wafer check valves are free from fluid leakage due to the tight seal between connecting parts.
- These valves are durable since they can be reused after being repaired.
- They can be installed either in the vertical or horizontal direction provided the direction will not affect fluid flow.
- Wafer check valves are versatile because they can be used in different industrial applications ranging from oil and gas to fresh water and wastewater.
- Wafer check valves can maintain the required pressure in the pipeline.
Disadvantages of wafer check valves
- Wafer check valves can only allow fluid to flow in one direction only.
- Wafer check valves are not suited for use in pulsation flows.
- The valve cannot be inspected while the valve is in use.
Troubleshooting wafer check valve
The wafer check valve is not operational
- The wafer check valve was installed in the wrong direction. Follow the wafer check valve manufacturer’s instructions regarding the installation of the valve and ensure the flow direction matches the arrow indicator on the valve body.
- The pipe is blocked. Check the valve for blockage and remove any foreign material causing blockage.
Fluid leakage when the wafer check valve is fully closed
- Worn out O-rings. Replace the O-rings.
- There are foreign materials lodged in the wafer check valve. Remove the foreign materials in the wafer check valve. Clean the valve.
External fluid leakage
- Damaged or worn-out O-rings. Replace the O-rings.
- Loose bolts and nuts. Tighten the bolts and nuts to the torque level recommended by the wafer check valve manufacturer.
- Worn out gasket. Replace the gasket.
Valve producing low fluid flow
- There is low pressure. Increase fluid pressure.
- The pipe is leaking fluid. Check the pipeline for leakage and repair them accordingly.
The wafer check valve is a type of check valve that uses a wafer-type disk to open and close the fluid flow. A wafer check valve has two ports the inlet and outlet and it is an automatic valve. This valve operates on the principle of pressure difference. When the inlet pressure is high, fluid has more energy which is used to lift the disk and thus fluid flows through the valve. When the fluid pressure is reduced or when the outlet pressure is more than the inlet pressure, the fluid flow reverses direction. At the instance the fluid attempts to reverse flow direction, the disc returns to its sealing position and thus prevents reverse fluid flow. Wafer check valve manufacturers produce these valves with the slim valve body and of various sizes for use in different industrial applications. The various types of wafer check valves include stainless steel wafer check valves, brass wafer check valves, and PVC wafer check valves. These valves are used in applications such as oil and gas industries, foods and beverages, fresh water supply, wastewater applications, chemicals, and swimming pools among others. Advantages of using wafer check valves are durable, versatile, low-pressure drop, ability to maintain pressure, lightweight, zero leakage, automatic operation, and they can be installed vertically or horizontally.