Swing Check Valves
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Swing check valve is designed with the purpose of easy maintenance in within system and to prevent back flow of system fluids. It is basically a one-way valve which the flow can run freely in one way. The traditional lever and weight swing check valve has an 80-90° stroke from fully open to fully close and it requires an external lever and weight to speed up the closure of the disc.
Gravity is insufficient to close the valve in fast speed. A weight is required to prevent reverse velocities slamming the disc into the valve seat. This may cause damage to the disc, seat and surrounding pipeline equipment.
Gravity is insufficient to close the valve in fast speed. A weight is required to prevent reverse velocities slamming the disc into the valve seat. This may cause damage to the disc, seat and surrounding pipeline equipment.
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Product Specifications
For more information on the individual product specifications, please click on the links below:
What are swing check valves?
1. What is swing check valve?
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The lever, weight, disc and lever assembly contains up to a dozen or so components which cause the snagging of rag in wastewater applications that can prevent the disc from sealing. It could completely block up the valve.
The small dimension swing check valve offers the possibility of priming by moving the lever manually. The weight is adjustable on the lever to achieve a soft closing against the seat as well as an optimum closing speed to prevent any leakage from the system. A guard covering the lever and weight is available as an extra safety, as it minimizes the risk of injuries. Limit switches are available to guard the valve for remote monitoring. |
ANSI 150# SS316 ​Swing Check Valve
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2. Why check valves slam?
A check valve relies on gravity and backflow to close properly. Check valve slam frequently occurs during pump shutdown. When a pump stops working, gravity and backflow slam the check valve shut. When the fluid is non-compressible, it creates a pressure or water hammer/shock wave. The fluid continues to flow back and forth until friction is lost which will cause the wave to solve.
Check valve slamming would cause crucial pressure surges in a running system that rattle pipes and damage other equipment. The valves will not slam without a reason. The real cause of slamming is due to poor sizing and selection. To select a proper check valve, the valve features below are the main consideration:
A check valve relies on gravity and backflow to close properly. Check valve slam frequently occurs during pump shutdown. When a pump stops working, gravity and backflow slam the check valve shut. When the fluid is non-compressible, it creates a pressure or water hammer/shock wave. The fluid continues to flow back and forth until friction is lost which will cause the wave to solve.
Check valve slamming would cause crucial pressure surges in a running system that rattle pipes and damage other equipment. The valves will not slam without a reason. The real cause of slamming is due to poor sizing and selection. To select a proper check valve, the valve features below are the main consideration:
- Pipeline size (OD)
- Application
- Seat type
- Installation type (vertical or horizontal)
- End connection
- Pressure rating
- Material compatible with medium
- Leakage requirements
3. Will a check valve stop water hammer?
JIS 10K SS316 ​​Swing Check Valve
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Water hammer is known as liquid hammer, is one of the common problems when applying check valve in system. It happens when the effect of high pressure shock waves occurs in relatively incompressible fluids and when the motion of fluids suddenly stops or change in direction. It leads to damage of check valve and pump damaging.
It often occurs when a valve closes suddenly at the end of a pipeline fluids system or a pump suddenly shuts down. Water hammer causes a pressure wave to form in the pipeline and will lead to excessive noise, vibration, and complete pipe collapse or system operation failure that causes a dangerous work environment. |
4. When would you use a swing check valve?
Swing check valve are used in many different industry applications. They often placed on the outlet side of a pump to avoid backflow. Check valve are essentially important for keeping water or fluids in pipelines. It is often used in heating, ventilating and air conditioning (HVAC) systems especially in large building where a coolant is pumped many storeys up. Installation of check valve is to ensure the coolant is not flushing back down.
Swing check valve are used in many different industry applications. They often placed on the outlet side of a pump to avoid backflow. Check valve are essentially important for keeping water or fluids in pipelines. It is often used in heating, ventilating and air conditioning (HVAC) systems especially in large building where a coolant is pumped many storeys up. Installation of check valve is to ensure the coolant is not flushing back down.
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By removing the bolts on the bonnet including hinge and disc from the valve body, the repair and maintenance job can be performed easily. The disc is mounted in a hinge pin, which allows it to move vertically and horizontally to close completely tight in case of any minor impurities in the seat. The seat is placed in a 20° angle providing tightness even at a low backflow pressure. The hinge is made of corrosion resistant material, stainless steel. It is firmly tightened around the shaft with bolts to ensure durability. The hinge can be placed in reverse position when limited space is available.
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ANSI 150# Cast Steel ​Swing Check Valve
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The benefit of using swing check valve:
- Bonnet and disc design gives easy access for repair jobs.
- Light weight disc requires a minimum force to operate the valve.
- Disc is able to move slightly in both horizontal and vertical way to fully close tightly.
- Allow full and unobstructed flow.
