Why does my check valve slam shut?
When a pump stops, gravity and reverse flow slam the check valve shut. Because fluid is non-compressible, it creates a pressure or shock wave (water hammer). The fluid continues to flow back and forth until friction losses cause the wave to settle.
Is dual plate check valve Non-slam type?
The Dual Plate Check Valve design is classified as “Non-Slam Design”. The disc in a swing check valve is hinged at the top. As the flow reduces, the closure of disc is influenced by force of gravity and high inertia of the heavy disc. This momentum can cause severe damage when the disc slams on to the valve seat.
What are the three types of check valves?
Check valves are unidirectional valves that provide unobstructed flow in one direction as long as flow pressure remains constant and protect the piping system against reverse flow. The three main types of check valves we offer are ball, piston, and stop check valves.
What are the 5 types of check valves?
Most common types of Check valves are swing, lift (piston and ball), butterfly, stop and tilting-disk.
How does a quiet check valve work?
A Quiet Check Valve is a great solution when extremely quiet operation is desired. Quiet Check Valve offer all the features as the standard check valve, with the addition of a spring-loaded hinged flapper mechanism which forces the flapper to fully close against fluid flow as the pump shuts down.
What is a silent check valve?
Silent check valves, also known as non-slam check valves and spring-assisted check valves reduce or eliminate water hammer and its effects. Water hammer refers to the high-pressure shock waves that occur when the flow of fluid abruptly stops (due to pump shut down or a valve disc quickly closing) in a piping system.
What is a dual plate check valve?
The dual Plate Check Valve is an all purpose non return valve that is much stronger, lighter in weight and smaller in size compared to a conventional swing check valve or life check valve. The Double Plate Check Valve employs two spring-loaded plates hinged on a central hinge pin.
What is a duo check valve?
Duo-Chek® high performance non-slam check valves are the original Mission Manufacturing Company wafer check valves introduced to the market in the late 50’s. The valve is available in the sizes, pressure classes and configurations required to meet the most demanding of applications.
Which check valve is best?
Swing check valves are the most common check valves. They are inexpensive and as they are automatic they do not require any external power or control to operate – only the flow direction determines the valve operation.
How do I choose a check valve?
Some of the things you may need to consider are fluid compatibility, flow characteristics, headloss, non-slam characteristics and total cost of ownership. For optimal performance, it is of course important to choose your valve respecting the characteristics of each specific installation.
Why is check valve so loud?
If you hear a loud noise every time you pump stops, you have a Standard Check Valve installed. That noise is the check valve closing which creates a slamming effect when the water flow reverses in the discharge pipe after the pump stops.
How do I make my check valve quieter?
To quiet them, replace the old check valve with a “silent” or “soft close” check valve. Remove the section of waste line under the check valve, disconnecting it at the union or coupling above the basin—or cutting the pipe. Drain the water above the check valve, then loosen the clamps and remove it (Photo 1).
Will a check valve stop water hammer?
“Any spring-loaded, poppet-style check valve is going to prevent water hammer because they close before reverse flow begins. It is one of their primary purposes,” explains Strait. well in vertical or horizontal positions with proper spring selection.
What causes check valve chatter?
Chatter results when the valve is not properly sized, and the maximum flow capacity of the valve does not closely match the system flow rate. Chatter may also result when the valve is operated with an inlet pressure close to its cracking pressure.
What is a wafer check valve?
Wafer check valves are in-line piping valves used to control fluid flow direction and reduce or fully prevent possible back flow within plumbing systems. Wafer check valves are also known as clack valves, reflux valves, non return valves and one way valves.
What is difference between swing type and wafer type check valve?
Wafer check valves are designed to fit into small spaces between two flanges, where swing check valves may not fit. One other major difference between swing check and wafer check valves is the wafer check valve restricts flow by a greater percentage than the swing check valve.
What is swing check valve?
A swing check valve is mounted with a disc that swings on a hinge or shaft. The disc swings off the seat to allow forward flow and when the flow is stopped, the disc swings back onto the seat to block reverse flow. The weight of the disc and the return flow has an impact on the shut-off characteristics of the valve.
Are two check valves better than one?
This employs two operating principles: firstly one check valve will still act, even if the other is jammed wide open. Secondly the closure of one valve reduces the pressure differential across the other, allowing a more reliable seal and avoiding even minor leakage.
Is a swing or spring check valve better?
A spring loaded check valve will help minimize effects of water hammer, while a swing check valve can exacerbate the issue. Any water hammering effects present in a piping system can potentially be amplified by a swing check valve.
When should check valves be used?
Check valves are used in many different applications. For example they are often placed on the outlet side of a pump, to protect the pump from backflow. Centrifugal pumps, the most common type of water pumps, are not self-priming, and therefore check valves are essential for keeping water in the pipes.
Why is my check valve so loud?
What does a quiet check valve do?
Silent check valves are an important part of any sump pump system. Installed in the discharge pipe leaving your sump pump, the quiet check valve prevents your pump from having to re-pump water it has already discharged.
How can water hammer be avoided?
The most important way to prevent water hammer is to remove the water from the steam lines before passing the steam again through them. Water is removed from the steam lines using drain connections. All the water should be drained out to make the lines clear.
What is non-Slam valve?
Non-slam check valves are designed specifically for use in these situations. As their name implies, these valves close without slamming, meaning no excess pressure spikes are created. The disc of a non-slam check valve has an internal spring opposing the opening fluid flow pressure.
How do I know if I have a bad check valve?
The signs of a failing swing check valve are often audible. When the disc opens and closes repeatedly (because of low-pressure flow) or violently (because of water hammer), it emits a tapping or hammering sound, respectively.