One of the most essential components in water and wastewater pumping systems is the check valve. Its primary function is to automatically open when pumps are operational and return to a closed position to prevent reverse flow when the pumps cease operation. These valves play a crucial role in reducing energy consumption and safeguarding the pumping system against pressure surges and damage that can occur due to reverse flow.
Selecting a check valve for a specific application can be likened to choosing hardware for new cabinetry. While the decision of which knob or handle to use is significant, it is only the first step in a process laden with various styles, colors, and price points. Similarly, once you've established the requirement for a check valve, you are faced with a multitude of choices. Each type of check valve is purpose-built to fulfill distinct needs. This overview will discuss the benefits and drawbacks of two popular styles: lift check valves and swing check valves.
Lift Check Valves
Lift check valves are extensively utilized in high-rise constructions, industrial facilities, power plants, and water and wastewater management systems. Known for their reliability and economical performance, these valves feature no external moving parts. However, due to the disc remaining in the flow stream when the system is running, lift check valves can lead to elevated energy costs over time.
Silent Check Valves
Silent check valves stand out for their ability to close quietly. The flow of liquid pushes the disc open to allow forward flow. Upon stopping the pump, a compression spring drives the disc into its seat before any reverse flow can occur, leading to the silent closure characteristic of this type of valve. Silent check valves are particularly well suited for clean water applications that operate under high pressure.
Moreover, nozzle check valves, which are akin to silent check valves, are designed for high-pressure settings, making them ideal for industrial and power applications.
Ball Check Valves
Ball check valves are prevalent in water and wastewater scenarios. Their straightforward design enables compactness and cost-effectiveness. These valves utilize a rubber-coated ball that shifts in and out of its seating depending on the flow direction. However, in high head applications, the ball's extended travel range can lead to slamming when the pump stops, which can be a concern for system integrity.
Swing Check Valves
Swing check valves rank among the most commonly used in water and wastewater pumping systems. They are easily accessible and relatively affordable. These valves operate automatically, functioning solely in response to the direction of flow without external power requirements. Different configurations exist, but they generally operate on the same principle.
Dual-Disc Check Valves
Featuring a wafer body design with dual D-shaped discs, dual-disc check valves rotate out of the way when flow enters the valve. They are recognized for their non-slam characteristics, though they are not recommended for wastewater applications due to susceptibility to vibration and wear.
Traditional Swing Check Valves
Traditional swing check valves are among the most recognizable types used in water and wastewater systems. Typically employing metal or resilient seats and a swing range between 60 to 90 degrees, this valve does have a propensity to create slamming effects due to its long stroke, packing friction, and the inertia of the disc. To mitigate slamming, air cushions can be installed; however, some experts recommend using a lever and spring combination to enable quicker closure.
Tilted Disc Check Valves
What differentiates tilted disc check valves from traditional swing check valves is their design that allows flow to pass from both sides of the disc. This feature significantly reduces head loss. However, similar to previous models, they are also not advisable for wastewater applications due to potential debris accumulation on pins extending into the flow stream. Clean water or treated effluent is optimal for this type of valve.
If you're uncertain about the suitability of your current check valve or considering potential alternatives, consulting an engineer with comprehensive knowledge of check valves is advisable. They could guide you to options that reduce slamming impacts or improve energy efficiency.
If you are pondering a switch for your check valve setup, don’t hesitate to reach out! We are more than willing to offer technical support to businesses and municipalities in Wisconsin, Minnesota, Illinois, and upper Michigan.
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