Inline Check Valves

Inline check valves, also called cartridge or poppet checks, pack a spring and disc into a compact threaded or barbed body that installs in any orientation, including straight-down vertical runs where a swing check will not work. They are the workhorse of chemical metering and dosing systems, small pumps, and instrumentation. 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.

Skip to results list
Availability
Price
to
The highest price is $928.99
Clear
Nominal Size
Style
Body Material
End Connection
Pressure Rating
Seal Material
35 items

Filter

Availability
Price
to
The highest price is $928.99
Nominal Size
Style
Body Material
End Connection
Pressure Rating
Seal Material

Where inline checks are used

Because the spring holds the disc closed until forward pressure overcomes a set cracking pressure, an inline check gives positive, orientation-independent closure in a small envelope. That makes it the standard fitting on metering pump discharge ports, chemical injection quills, RO and water-treatment skids, air and vacuum lines, and OEM equipment. For pump-mounted barrel and cartridge styles, see metering pump check valves.

Materials and seals

Brass bodies handle water, oil, gas, and compatible chemicals to 500 PSI. 316 stainless resists chlorine, acids, and aggressive media that attack brass. PVC suits chemical dosing and low-pressure water. Seals come in Buna-N (NBR) for general service or Viton (FKM) for hydrocarbons and harsh chemicals. Not sure which seal? Read Buna vs. Viton seats.

Sizes and connections

Female NPT, male NPT, hose barb, and glue/socket connections from 1/8 in. through 2 in. Spring-loaded designs seat cleanly and repeatably, which is what dosing accuracy depends on.

Common questions

Which way does an inline check valve install?

In any orientation, including vertical up or down, as long as the flow arrow points downstream. That orientation freedom is the main reason to choose inline over swing.

What is cracking pressure?

The forward pressure needed to open the valve against its spring, typically a few PSI. It matters most in low-pressure and metering applications; check the spec on each product page.