Inline Check Valves

Inline check valves, also called cartridge or poppet checks, place a spring and disc in a compact threaded or barbed body. Apex Flow Solutions stocks inline check valves from 1/8 in. up in brass, 316 stainless, and PVC, sold one at a time with no minimum. Ratings, seals, connections, and sizes vary by model; confirm the specification on the product page.

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Brass In-Line Check Valves — High Capacity

One spring-loaded design, eleven sizes, NBR or Viton seal — pick size and seal in one place.

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316 Stainless Steel In-Line Check Valves — 800 WOG

Eight sizes from 1/4 in. to 2 in., FNPT × FNPT, PTFE seat, and 800 WOG across the series.

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Where inline checks are used

An inline check gives compact, orientation-flexible closure in a small envelope, which is why it is commonly used on metering-pump discharge ports, injection points, water-treatment skids, air and vacuum lines, and OEM equipment. Confirm the orientation rating for your installation on the product page. For pump-mounted barrel and cartridge styles, see metering pump check valves.

Materials and seals

Brass, 316 stainless, and PVC bodies are offered, with Buna-N (NBR) and Viton (FKM) seal options depending on the model. Pressure ratings vary by product. For seal selection, read Buna vs. Viton seats, and confirm compatibility against the manufacturer data.

Sizes and connections

Female NPT, male NPT, hose barb, and glue/socket connections across the stocked range. Check the size and connection on each product.

Common questions

Which way does an inline check valve install?

Install with the flow arrow pointing downstream. Orientation freedom varies by model, so confirm the orientation rating on the product page.

What is cracking pressure?

The forward pressure needed to open the valve against its spring. It matters most in low-pressure and metering applications; check the value on each product page.