Swing Check Valve

QS Valve: Zhangzhou Swing Check Valve

Swing check valve, 2 to 24 inch and 150LB to 2500LB, with a swing disc and bolted cover that stops reverse flow at low pressure drop.

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One-Minute Overview

Swing check valve that closes on reverse flow and opens again as soon as the line pushes forward.
Sizes 2 to 24 inch, classes 150LB to 2500LB to BS 1868 and ASME B16.34.
Swing disc hangs out of the flow path, so pressure drop stays low in normal service.
Bolted cover allows inspection and disc replacement without cutting the valve out.

A swing check valve is a one-way door for a pipeline. A disc hangs on a hinge above the flow path; forward pressure swings it open, and any reverse flow drops it back onto the seat. There is no actuator and no operator, which makes the valve cheap to run and reliable on lines where backflow would damage a pump or drain a system. The swing disc sits mostly out of the stream, so the valve adds little resistance in normal operation.

Name: Swing Check Valve
Type: Swing Check Valve
Size: 2-24 Inch
Class: 150LB-2500LB
Material: WCB, WC6, CF8, CF8M
Standard: BS 1868, ASME B16.34
Connection: Flanged RF or Butt Weld
Feature: Bolted cover with swing disc and low pressure drop

Install with the flow arrow on the body pointing the right way, which sounds obvious until a valve is fitted backwards and chatters all shift. Horizontal runs are the default, with the hinge pin above the pipe so the disc drops onto the seat under gravity; vertical upflow works too. Keep the valve a few pipe diameters away from pumps and elbows so the flow arriving at the disc is steady, and size the valve for the real flow rate rather than the line size alone.

Water hammer is the usual enemy of a swing check, because a heavy disc slamming shut on a long line sends a pressure wave back down the pipe. Slower-closing discs, a dashpot, or a non-slam design are the normal fixes where pumps trip or lines are long. Overhaul is straightforward: unbolt the cover, lift out the disc and hinge, lap or replace the seat and disc ring, and reassemble. Disc material, seat ring and pressure class are confirmed per inquiry, and a detailed specification sheet is available on request.

FAQ

Q1. What makes a swing check valve chatter on some installations?

Chatter comes from flow that is not steady: turbulence from a nearby elbow, a pump running near the end of its curve, or a disc heavy enough to bounce on the seat. Adding straight pipe before the valve, moving it a few diameters from the pump, or specifying a non-slam disc usually restores quiet operation.

Q2. Does it matter which way I face the thing when I bolt it in?

Absolutely. The flow arrow on the body must point downstream, otherwise the disc blocks the line and slams on every start. On horizontal runs keep the hinge pin above the pipe so gravity helps the disc seat. Give the valve a few pipe diameters of straight run before it so the flow arrives calm.

Q3. My pump growls after every shutdown - is the check valve the villain?

Quite possibly. When the pump stops, the returning column of flow slams the disc shut and sends a pressure wave back up the line. That water hammer is the growl you hear. A slower closing disc, a dashpot, or a non-slam design tames it, especially on long discharge lines.

Q4. What's the minimum I can order?

Standard flange insulation gasket kits start at one set, and standard gaskets, studs, washers and sleeves start at one piece. Valves made to your drawing or for a non-standard bolt pattern are quoted individually, because the minimum really depends on the material and the tooling involved.

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