Slow Closing Check Valve

‌Slow-closing check valve‌ is an automatic valve used to prevent the backflow of media. Its characteristic is that the closing process is divided into two stages: quickly closing most of the channels and then slowly closing the remaining opening. By delaying the closing time, the water hammer pressure is reduced to protect the pipeline system from impact damage. It is suitable for high-pressure, large-caliber or long-distance transportation scenarios where the one-way flow of fluids needs to be controlled and there is a risk of hydraulic shock.

Slow-closing check valve structure:
‌Valve body and valve disc‌
‌Valve body‌: Mostly adopt straight-through or inclined flow channel design (cast iron, stainless steel and other materials) to reduce flow resistance and adapt to different media.
‌Valve disc‌: Butterfly, spherical or lifting disc structure, controllable motion trajectory through hinges or guide rods.
‌Slow-closing mechanism‌ (core component)

‌Hydraulic damping system‌: The oil cylinder and the piston are linked to the valve disc, and the oil discharge speed is adjusted through the throttle valve to control the closing time (usually 3-60 seconds).
‌Spring assistance‌: Some designs combine spring force to achieve segmented closing and enhance the buffering effect.
‌Sealing system‌

The valve disc and valve seat adopt metal hard seal (alloy cladding) or soft seal (rubber, PTFE) to ensure zero leakage.

 

Slow closing check valve

 

Advantages of slow-closing check valves:
‌Water hammer protection‌: By delaying the closing time, the water hammer pressure peak is reduced by more than 60%, avoiding pipeline bursting or equipment damage.
‌Low flow resistance and high sealing‌: The optimized flow channel design reduces pressure loss, and the sealing material has strong corrosion resistance and is suitable for acid and alkali media.
‌Long life and low maintenance‌: The guide device avoids valve disc deflection and jamming, and the key components are wear-resistant, with a life of more than 30 years.

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Application of slow-closing check valves

‌Water engineering‌: high-rise building water supply system, municipal pipeline network, to prevent pump stop backflow and water hammer impact.
‌Industrial field‌: Chemical reactor medium transportation, oil pipeline high-pressure oil control, power cooling circulation system.
‌Fire protection system‌: Fire pump outlet pipeline, to ensure smooth pressure transition during emergency shutdown.
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Problems solved by slow-closing check valves‌

Eliminate the risk of pump reversal and equipment damage caused by medium backflow.

Reduce noise pollution and mechanical vibration when the valve is closed.
Suitable for special working conditions with particles and high viscosity media (such as sewage and mud).

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