Y check Valve

What is a Y-check valve? 

This is a check valve which is a modification of a standard check valve in which the valve disc/ball is mounted at an angle to the axis of the pipe. This angle of the disc to the pipe creates a valve of Y-shape. As such, it was named the “Y-check valve”. This type of valve is used to prevent fluid from reversing in the piping system. The flow of fluid in the reverse direction happens when the pump turns off or when there is a backflow of fluid. Preventing reverse fluid flow is very important since it helps to prevent contamination in applications like foods and water as well as prevent damage to equipment like boilers and pumps. Y-check valve manufacturers design various types of these valves with certain material properties making them suitable for use in a specific area of application. The valve in the market will have a user manual from the Y-check valve manufacturer illustrating how the valve can be used and also working parameters such as temperature, pressure, and velocity among others. Following such parameters from the check valve manufacturer helps the valve serve for a long period. 

Figure: Y-check valve.

Components of Y-check valve 

Body 

The body of a Y-check valve is used to cover internal parts. Y-check valve manufacturers design the body with strong materials to guarantee high strength which can protect internal parts against impact. Also, the body is made strong so that it can withstand high-pressure levels in the fluid flowing. Y-check valve manufacturer makes the body with the inlet and outlet valve ports where fluid enters and leaves the valve respectively. 

Bonnet 

This is a component of a Y-check valve which is placed on top of the valve body. The cover is made of the same material as the body to enhance high strength. The bonnet and body connection can be done by use of bolts, threads, or welding. Each of these connecting methods has its advantages and disadvantages. 

Disc 

This is the part responsible for opening and closing fluid flow. The disc opens when suction pressure is high and it closes once this pressure reduces or there is backflow. 

Seat 

This is a component of a Y-check valve where the disc/ball rests while closing the valve. The seat is mounted between the inside of the body and the disc to prevent leakage when the valve prevents reverse flow. 

Spring 

This is a component of a Y-check valve that is used to help the valve disc or ball to return to the closing position once the pump is turned off or when a pressure drop occurs. Y-check valve manufacturers design the valve spring with strength directly proportional to the valve working pressure so that the disc can open with ease. 

Figure: Components of a Y-check valve.

How does a Y-check valve work? 

A Y-check valve allows fluid flow by using pressure difference. The pressure difference is obtained by having a higher suction pressure than the outlet pressure. With such a positive pressure difference, the fluid can create a force that acts on the valve disc/ball to pull it up towards the valve bonnet. This helps the fluid create a free path where it flows through the check valve. With high suction pressure, the valve disc/ball remains open until the time when the pump is stopped or when the fluid pressure reduces. In that instance, the valve spring gets relieved and it starts reverting forcing the disc to the seating position. While the disc/ball is in its seating position it prevents any fluid from flowing backward. Other Y-check valve manufacturers design the valve without the spring. In such valves, the disc is forced back to the valve seat by gravity or by backflow. 

Types of Y-check valves 

Spring loaded Y-check valve 

This is a Y-check valve that uses a spring component to open and close the fluid flow. Y-check valve manufacturers orient the valve spring at an angle to the pipe. This type of Y-check valve opens when the high inlet fluid pressure acts on the valve disc compressing the spring to move up along the valve bonnet leaving a free path for fluid flow. This type of valve can be installed in a vertical or horizontal position and operate without stalling.

Figure: Spring loaded Y-check valve.

Ball operated Y-check valve 

This is a Y-check valve in which the closing component that prevents reverse fluid flow is a ball. This type valve can be assisted by a spring or it can work without the valve spring. Those valves made of spring can be installed in vertical or horizontal positions without stalling. The valves without the spring can close using backflow or gravity force. The ball moves along the valve bonnet to open the valve. The ball starts moving downwards to the valve seat when the inlet pressure reduces. Ball-operated Y-check valve manufacturers design the ball from various materials which helps to work on different types of media. Some balls are coated with strong materials to help prevent abrasive wear as well as be able to withstand high temperatures. Such ball-operated Y-check valves can be used in applications with slurries as well as in steam applications. 

Figure: Ball operated Y-check valve.

Plastic Y-check valve 

This is a special type of Y-check valve which is made of fully plastic material. Y-check valve manufacturers design these valves for use only at low temperatures below 60 ^oC. Plastic Y-check valves are very good when it comes to corrosive media. This is because plastic materials are much better at resisting corrosion compared to their metallic counterparts. Plastic materials are also cheaper compared to metallic ones and this makes these valves cheaper. Plastic Y-check valves are made of materials such as polyvinyl chloride and propylene among others. A Y-check valve made of plastic material is light in weight compared to a metallic ones due to the low density associated with plastics. However, plastic Y-check valves have low strength relative to metallic ones and thus they can only be used at low to moderate pressure levels. Very high pressure can damage the valve or cause fluid leakage through connections.

Figure: Platsic Y-check valve.

Flanged end Y-check valve 

This is a Y-check valve that is connected to the pipe using bolts and nuts. Y-check valve manufacturers design this type of valve with flanges at the inlet and outlet ports. The pipe end to be connected to the Y-check valve is also made with a flanged end. This flanged end has holes. The bolts are inserted through these holes. Y-check valve manufacturer designs this type of valve for use in high-pressure applications. The use of several bolts and nuts makes the connection very tight and free from fluid leakage thus recommended for use in high pressure. 

Flanged end Y-check valve manufacturer uses strong metallic materials like stainless steel and ductile iron to make these valves. Soft materials are also used to make internal parts such as seats and rings. However, such valves with soft materials are recommended for use in low-temperature applications. Despite the flanged end Y-check valve being very strong and having a tight seal, they are large in size and heavy in weight. The high weight emanates from the use of several bolts and nuts and extra material used to make the flanges. 

Figure: Flanged end Y-check valve.

Threaded end Y-check valve 

This is a type of Y-check valve that is connected to the pipe using threads. This type of valve can also have the bonnet and body connected using threads or welded together. Threaded end Y-check valve manufacturers produce this type of valve for use in medium pressure applications. Depending on the material used to make internal parts, the valve can be used from low to high temperature according to the Y-check valve manufacturer’s instructions. One advantage of using a threaded end Y-check valve is that it is light in weight and smaller in size relative to the bolted type. This type of valve can be opened for cleaning, inspection, and repair. 

Figure: Threaded end Y-check valve.

Applications of Y-check valves 

• Y-check valves are used in the production of foods and beverages. 
• They are used in fresh water supply systems. 
• They are used in the treatment of wastewater. 
• Y-check valves are used in oil and gas refineries.
• They are used in chemicals and petrochemical applications. 
• These valves are used in steam power generating plants. 
• They are used in firefighting applications. 

Advantages of Y-check valves 

• Y-check valves can be inspected, cleaned, and or repaired without the need to remove them from the pipe connection. 
• These valves are automatically operated by the use of pressure difference between the inlet and outlet. 
• Y-check valves are free from fluid leakage due to the tight seals used. 
• These valves have a low-pressure loss which helps to enhance high pumping efficiency. 
• Y-check valves are free from lubrication. 
• These valves maintain working pressure while in operation. 
• Y-check valves do not allow reverse fluid flow.
• They are can be used in both low and high-temperature applications. 
• Y-check valves are fast acting when opening or closing fluid flow. 
• These valves are versatile since they are used in different applications ranging from corrosive to non-corrosive media.

Disadvantages of Y-check valves 

• These valves occupy more space compared to other check valves. 
• Y-check valves can only allow fluid flow in one direction. 
• These valves are not suitable for use in pulsating fluid flow.  

Troubleshooting Y-check valves 

High vibration or noise levels 

• High fluid velocity. Ensure the flow velocity matches the value recommended by the Y-check valve manufacturer. 

Reverse fluid flow 

• Valve is not fully closed. Open the valve and check if the disc/ball could be stuck open by foreign materials. Remove the materials.

Fluid leakage in the valve 

• Worn out/damaged O-rings. Replace the O-rings. 
• Damaged/worn-out seat. Replace the seat. 
• Debris inside the valve. Clean the debris. 

Fluid leakage through valve connections 

• Loose bonnet. Tighten connecting bolts or screws. 
• Loose valve-pipe connection. Tighten the bolts or screws. 
• Damaged gasket. Replace the gasket. 

Zero fluid flow through the Y-check valve 

• Low fluid pressure. Increase the fluid pressure to the value required by the Y-check valve manufacturer to ensure there is enough force to open the disc/ball.
• Wrong direction of installation. Install the valve again ensuring the flow direction is the same as the direction of flow indicated by the arrow on the valve body. 
• Pipe blockage. Check the pipe conveying the fluid to the Y-check valve for any blockage. If it is blocked remove the blocking material. 
• Closed downstream valve. Check the valve downstream if it is open and if not open it. 

Summary 

A Y-check valve is a type of valve designed with the valve seat oriented at an angle to the pipe axis. This type of valve works on the principle of pressure difference in which the incoming fluid forces the valve disc/ball upwards along the bonnet. Moving the disc upwards leaves space where fluid flows through the valve. Y-check valves are not operated manually or using actuators but they are designed to open and close on their own. The valve closes when the suction pressure reduces or when the pump stops. Y-check valve manufacturers design these valves with various materials. It is the material used to make the valve that deactivates the conditions and areas of applications. Some valves are meant for corrosive, high pressure, high temperature, and slurries while others are not. As such, it is recommended to consult valve experts or manufacturers to know the best valve for that application. 

Y-check valve manufacturers produce various types of these valves which include flanged end Y-check valves, threaded end Y-check valves, plastic Y-check valves, spring loaded Y-check valves, and ball operated Y-check valves among others. Y-check valves are used in different industries such as oil and gas, chemicals, foods, and wastewater treatment among others. Using Y-check valves will have advantages such as automatic operation, no lubrication needed, zero leakage, high efficiency, fast operation, no reverse fluid flow, and they are versatile.