Check Valves

Check valves are automatic one-way flow control valves that open under forward pressure and close immediately when flow stops or reverses — protecting pumps, equipment, and processes from backflow, siphoning, and contamination. Unlike ball valves or gate valves, check valves require no operator action; they respond to flow conditions automatically.

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Apex Flow Solutions carries brass, stainless steel, and PVC check valves in spring-loaded inline, Y-pattern, swing disc, barrel, and anti-siphon configurations — covering chemical metering pump systems, water treatment plants, HVAC hydronic circuits, pump discharge lines, and general industrial process piping.

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Brass inline check valves handle water, oil, gas, and compatible chemical service at pressures up to 500 PSI. Available with Buna-N (NBR) or Viton (FKM) seals — Viton is specified for hydrocarbon or aggressive chemical compatibility. 316 Stainless steel check valves — including barrel spring, Y-spring, swing disc, and inline styles — resist chlorine, acids, and corrosive industrial chemicals that attack brass. PVC check valves with socket or NPT connections are the chemical-dosing standard for water treatment, RO systems, and pool/spa plumbing.

Anti-Siphon and Metering Pump Applications

Aluminum anti-siphon valves prevent loss of pump prime and chemical back-migration in chemical dosing systems. Barrel spring check valves attach directly to metering pump outlet ports and are the most common check valve in water treatment chemical injection.

Related Technical Resources

Frequently Asked Questions

Which type of check valve do I need for my application?

Spring-loaded inline check valves are the most common choice for pump discharge lines and process piping because they close instantly when flow stops, preventing water hammer. Swing disc valves are preferred for lower-pressure gravity-fed lines where cracking pressure matters. Barrel spring check valves mount directly to metering pump outlet ports and are standard in chemical dosing systems. See our Check Valve Types Guide for a full comparison by application.

Does a check valve have to be installed in a specific direction?

Yes — check valves are directional and must be installed with the flow arrow on the body pointing in the direction of intended flow. Installing a check valve backwards means it will block forward flow and fail to prevent backflow. For spring-loaded inline check valves, the spring end faces upstream; for swing check valves, the hinge pin must be at the top for horizontal pipe runs. See our Check Valve Installation Direction Guide for orientation diagrams.

What is the difference between a spring check valve and a swing check valve?

A spring check valve uses a coil spring to hold the disc closed until forward pressure overcomes the spring's cracking pressure, giving fast positive closure and the ability to work in any orientation including vertical downflow. A swing check valve uses gravity and backflow pressure to seat a hinged disc, making it low-restriction but limited to horizontal or vertical-upflow installation. Spring checks are the better choice for pump protection; swing checks suit low-pressure gravity drain lines.

Guides for Choosing

Need help picking the right check valve? Check Valve Sizing Guide · Orientation & Installation · Check Valve Types Compared · Buna vs. Viton Seats · Slamming & Water Hammer