Inline check valves put the check mechanism inside a compact body that threads or glues directly into the line. Apex Flow Solutions carries them in brass, cast bronze, 304 and 316 stainless steel and PVC, with threaded and socket ends. Match the size, thread and seal material to the valve you are replacing.
View all inline check valves (51)Matching an existing valve? Send the part number or thread sizeSearch by part number
Shop by body or seal
Body and seal
All inline check valves
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1/4 in. Inline Check Valve -
3/8 in. Brass Inline Check Valve, Buna-N -
3/8 in. Brass Inline Check Valve, Viton -
1/2 in. Brass Inline Check Valve, Viton -
1/2 in. Brass Inline Check Valve, Threaded -
3/4 in. Brass Inline Check Valve, Buna-N -
3/4 in. Brass Inline Check Valve, Viton -
3/4 in. Brass Inline Check Valve, Threaded -
1 in. Brass Inline Check Valve, Buna-N -
1 in. Brass Inline Check Valve, Viton -
1 in. Brass Inline Check Valve, Threaded -
1-1/4 in. Brass Inline Check Valve, Viton -
1-1/2 in. Brass Inline Check Valve, Buna-N -
1-1/2 in. Brass Inline Check Valve, Viton -
1-1/2 in. Brass Inline Check Valve, Threaded -
2 in. Brass Inline Check Valve, Buna-N -
2 in. Brass Inline Check Valve, Viton -
2 in. Brass Inline Check Valve, Threaded -
2-1/2 in. Brass Inline Check Valve, Buna-N -
2-1/2 in. Brass Inline Check Valve, Viton -
3 in. Brass Inline Check Valve, Buna-N -
3 in. Brass Inline Check Valve, Viton -
4 in. Brass Inline Check Valve, Buna-N -
4 in. Brass Inline Check Valve, Viton
Inline and spring check valves
Inline check valves are usually spring-loaded. Our Spring Check Valves collection groups other spring-loaded models by closing mechanism, and three PVC models appear in both collections. Shop here when you are matching a compact body by size and connection.
How an inline check valve works
Forward flow lifts a poppet or disc off its seat. When forward pressure drops, the spring closes it against the seat. The pressure needed to open the valve, the cracking pressure, differs by model; ask us for the cracking pressure of a specific valve.
Bodies, seals and connections
| Body | End connections | Seal |
|---|---|---|
| Brass | Female NPT | Buna-N or Viton on most models, by part number |
| Cast bronze (Midland 947140, 947143, 947144, 947145) | Female NPT | PTFE |
| 316 stainless steel | Female NPT | PTFE |
| 304 stainless steel (Midland 949430) | Female NPT | Fluoroelastomer |
| PVC | Female NPT or socket (glue) | Not listed by Midland; ask us |
Not sure which seal your existing valve uses? Ask us with the part number.
Common questions
Which way does an inline check valve install?
With the flow arrow on the body pointing downstream. Follow the manufacturer's installation instructions for the specific model.
Can I replace a brass inline check valve with stainless steel?
Match the size, thread and seal first. If service conditions matter for your choice, send us the details and we will help match the valve.
Do you carry inline check valves with Viton seals?
Yes. Use the Viton seal filter above, or ask us for a specific part number.