{"id":3025,"date":"2026-07-07T03:30:50","date_gmt":"2026-07-06T19:30:50","guid":{"rendered":"http:\/\/www.cvprimasolo.com\/blog\/?p=3025"},"modified":"2026-07-07T03:30:50","modified_gmt":"2026-07-06T19:30:50","slug":"what-is-the-function-of-the-check-valve-in-a-screw-pump-4672-a65867","status":"publish","type":"post","link":"http:\/\/www.cvprimasolo.com\/blog\/2026\/07\/07\/what-is-the-function-of-the-check-valve-in-a-screw-pump-4672-a65867\/","title":{"rendered":"What is the function of the check valve in a screw pump?"},"content":{"rendered":"

As a supplier of screw pumps, I’ve had numerous inquiries from clients about various components of these pumps. One question that frequently comes up is about the function of the check valve in a screw pump. In this blog, I’ll delve into the details of the check valve’s role, its importance, and how it impacts the overall performance of a screw pump. Screw Pump<\/a><\/p>\n

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The Basics of Screw Pumps<\/h3>\n

Before we discuss the check valve, it’s essential to understand the working principle of a screw pump. A screw pump is a positive displacement pump that uses one or more screws to move fluid along the screw axis. The screws intermesh, creating chambers that trap and move the fluid from the suction side to the discharge side. Screw pumps are known for their smooth, continuous flow, high efficiency, and ability to handle viscous fluids. They are widely used in various industries, including oil and gas, food and beverage, chemical, and marine.<\/p>\n

What is a Check Valve?<\/h3>\n

A check valve, also known as a non – return valve or one – way valve, is a mechanical device that allows fluid to flow in one direction only. It consists of a valve body, a disc or ball, and a seat. When the fluid pressure on the inlet side is higher than the pressure on the outlet side, the disc or ball is pushed off the seat, allowing the fluid to flow through the valve. When the pressure on the outlet side exceeds the inlet pressure, the disc or ball is forced back onto the seat, preventing the reverse flow of the fluid.<\/p>\n

Functions of the Check Valve in a Screw Pump<\/h3>\n

1. Preventing Backflow<\/h4>\n

One of the primary functions of the check valve in a screw pump is to prevent backflow. In a screw pump system, once the pump stops operating, the fluid in the discharge line may tend to flow back towards the pump due to gravity or pressure differences. This backflow can cause several problems. It can damage the pump’s internal components, such as the screws and bearings, by subjecting them to reverse forces. Additionally, backflow can lead to a loss of prime in the pump, which means the pump will have difficulty restarting and may require additional priming steps. The check valve acts as a barrier, ensuring that the fluid remains in the discharge line and does not flow back into the pump.<\/p>\n

2. Maintaining System Pressure<\/h4>\n

The check valve helps in maintaining the pressure in the system. When the screw pump is operating, it builds up pressure in the discharge line to move the fluid to the desired location. The check valve ensures that this pressure is maintained even when the pump stops. By preventing backflow, the check valve keeps the fluid in the discharge line under pressure. This is particularly important in systems where a constant pressure is required, such as in hydraulic systems or in processes where the fluid needs to be delivered at a specific pressure.<\/p>\n

3. Protecting the Pump from Water Hammer<\/h4>\n

Water hammer is a phenomenon that occurs when there is a sudden change in the flow velocity of a fluid in a pipeline. This can happen when a pump is suddenly stopped or a valve is rapidly closed. The sudden change in flow velocity creates a pressure wave that can travel through the pipeline and cause damage to the pump and other components. The check valve can help mitigate the effects of water hammer. When the pump stops, the check valve closes quickly, preventing the pressure wave from traveling back towards the pump. This protects the pump from the high – pressure spikes associated with water hammer.<\/p>\n

4. Facilitating Pump Priming<\/h4>\n

In some cases, the check valve can assist in the priming process of the screw pump. Priming is the process of filling the pump and the suction line with fluid before starting the pump. The check valve can hold the fluid in the suction line, preventing it from draining out when the pump is not in operation. This makes it easier to prime the pump when it needs to be started again, as there is already fluid in the suction line.<\/p>\n

Types of Check Valves Used in Screw Pumps<\/h3>\n

There are several types of check valves that can be used in screw pump systems, each with its own advantages and disadvantages.<\/p>\n

Swing Check Valves<\/h4>\n

Swing check valves have a disc that is hinged at the top of the valve body. When the fluid flows in the forward direction, the disc swings open, allowing the fluid to pass through. When the flow reverses, the disc swings back onto the seat, closing the valve. Swing check valves are relatively simple in design and are suitable for low – to medium – pressure applications. However, they can be slow to close, which may not be ideal in applications where rapid closing is required to prevent water hammer.<\/p>\n

Ball Check Valves<\/h4>\n

Ball check valves use a ball as the closing element. The ball is free to move within the valve body. When the fluid flows in the forward direction, the ball is pushed off the seat, allowing the fluid to pass. When the flow reverses, the ball is forced back onto the seat, closing the valve. Ball check valves are known for their quick closing action, which makes them suitable for applications where water hammer is a concern. They are also relatively compact and can be used in high – pressure applications.<\/p>\n

Lift Check Valves<\/h4>\n

Lift check valves have a disc that is lifted off the seat by the fluid flow. When the flow reverses, the disc drops back onto the seat, closing the valve. Lift check valves are often used in applications where the flow rate is relatively low and the pressure is high. They provide a tight seal and are less prone to leakage compared to some other types of check valves.<\/p>\n

Factors to Consider When Selecting a Check Valve for a Screw Pump<\/h3>\n

When selecting a check valve for a screw pump, several factors need to be considered.<\/p>\n

Flow Rate<\/h4>\n

The flow rate of the screw pump system determines the size and capacity of the check valve. The check valve should be able to handle the maximum flow rate of the pump without causing excessive pressure drop.<\/p>\n

Pressure<\/h4>\n

The operating pressure of the system is another important factor. The check valve should be rated for the maximum pressure that the system may experience. This ensures that the valve can operate safely and effectively without leaking or failing.<\/p>\n

Fluid Characteristics<\/h4>\n

The characteristics of the fluid being pumped, such as its viscosity, temperature, and corrosiveness, also play a role in the selection of the check valve. For example, if the fluid is highly viscous, a check valve with a larger opening may be required to allow the fluid to flow through easily. If the fluid is corrosive, the valve should be made of a material that is resistant to corrosion.<\/p>\n

Installation Location<\/h4>\n

The location of the check valve in the system can also affect its performance. It should be installed as close as possible to the pump’s discharge to prevent backflow effectively. Additionally, the valve should be installed in a position that allows for easy maintenance and inspection.<\/p>\n

Conclusion<\/h3>\n

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The check valve is a crucial component in a screw pump system. Its functions of preventing backflow, maintaining system pressure, protecting the pump from water hammer, and facilitating pump priming are essential for the proper operation and longevity of the pump. As a screw pump supplier, I understand the importance of selecting the right check valve for each application. By considering factors such as flow rate, pressure, fluid characteristics, and installation location, we can ensure that our clients’ screw pump systems operate efficiently and reliably.<\/p>\n

Screw Pump<\/a> If you are in the market for a screw pump or need advice on the selection of a check valve for your existing pump system, I encourage you to reach out to me. I’m more than happy to discuss your specific requirements and provide you with the best solutions.<\/p>\n

References<\/h3>\n