Spring check valves use a spring to return the disc to its seat, so they open once forward pressure exceeds the spring and close when flow stops. Apex Flow Solutions groups the spring-loaded families here: brass spring check valves, stainless barrel-spring and inline spring models, and PVC spring-loaded inline valves.
Narrow the selection
All spring check valves
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1/8 in. Brass Spring Check Valve, 500 PSI, Female NPT x Female NPT, NBR Seal -
1/8 in. Brass Spring Check Valve, 500 PSI, Male NPT x Female NPT, NBR Seal -
1/8 in. Brass Spring Check Valve, 500 PSI, Female NPT x Female NPT, Viton Seal -
1/8 in. Brass Spring Check Valve, 500 PSI, Male NPT x Female NPT, Viton Seal -
1/4 in. Brass Spring Check Valve, 500 PSI, Female NPT x Female NPT, NBR Seal -
1/4 in. Brass Spring Check Valve, 500 PSI, Female NPT x Female NPT, Viton Seal -
1/4 in. Stainless Steel Barrel Spring Check Valve -
1/4 in. Stainless Steel Female x Female Spring Check Valve -
1/4 in. Stainless Steel Spring Check Valve, MPT x FPT -
3/8 in. Barrel Spring Check Valve -
3/8 in. Stainless Steel Spring Check Valve, FPT x FPT -
3/8 in. Stainless Steel Spring Check Valve, MPT x FPT -
1/2 in. Inline Female x Female PVC Spring-Loaded Check Valve -
1/2 in. Brass Spring Check Valve, 500 PSI, Female NPT x Female NPT, NBR Seal -
1/2 in. Barrel Spring Check Valve -
1/2 in. Stainless Steel Male x Female Spring Check Valve -
1/2 in. Stainless Steel Spring Check Valve, FPT x FPT -
3/4 in. Female x Female PVC Inline Spring-Loaded Check Valve -
3/4 in. Brass Spring Check Valve, 500 PSI, Female NPT x Female NPT, NBR Seal -
3/4 in. Brass Spring Check Valve, 500 PSI, Female NPT x Male NPT, NBR Seal -
3/4 in. Brass Spring Check Valve, 500 PSI, Female NPT x Female NPT, Viton Seal -
3/4 in. Brass Spring Check Valve, 500 PSI, Female NPT x Male NPT, Viton Seal -
3/4 in. Stainless Steel Barrel Spring Check Valve -
3/4 in. Stainless Steel Spring Check Valve, FPT x FPT
About spring check valves
A spring check valve holds a disc or poppet against its seat with a spring. It opens when forward pressure exceeds the spring and closes when flow stops. Apex groups four spring-loaded families here, all Midland Industries.
The four families
- Brass inline spring — in-line threaded body in brass, with an NBR (Buna-N) or Viton seal. Sizes 1/8 in. to 3/4 in.
- 316 stainless inline spring — the Midland "316 SS Spring Check Valves" series (catalog p.322), in-line threaded, FNPT×FNPT or MNPT×FNPT, 1/4 in. to 1 in.
- Stainless barrel (2-piece) spring — a barrel-style body (catalog p.323), 1/4 in. to 2 in., NBR seat. Midland lists the body as CF8M/CF8 cast stainless; confirm the grade for a specific size with us.
- PVC inline spring — spring-loaded plastic inline body, threaded.
Midland ratings by family
Each rating below applies only to the family named. Do not read one family's rating across the others; confirm the exact specification on the product page. Ask us for temperature ratings; Midland's catalog and product data state them differently, and we confirm them for the exact model.
| Family | Working pressure | Other Midland specs |
|---|---|---|
| Brass inline spring | 500 PSI | NBR or Viton seal (per model) |
| 316 stainless inline spring | 1500 PSI | Opening (cracking) pressure 2–3 PSI; medium W.O.G. (catalog p.322) |
| Stainless barrel spring | 300 PSI | Opening pressure 2 PSI; NBR seat (catalog p.323) |
| PVC inline spring | Ask us for the current rating | Threaded ends |
Choosing
Match the valve's end connections to the adjoining pipe or fittings. FNPT ends connect to male NPT threads; MNPT ends connect to female NPT threads. On brass models the seal (NBR or Viton) is the other decision. Follow the flow arrow and the manufacturer's installation instructions, and ask us about pressure and temperature for your service before ordering. To match a compact inline valve by size and thread, see inline check valves.
Frequently asked questions
How should a spring check valve be installed?
With the flow arrow pointing downstream. Follow the manufacturer's installation instructions and confirm the installation position on the product data for your specific model.
What is the difference between the inline and barrel styles?
Both use a spring, but the barrel style uses a 2-piece barrel body (catalog p.323) while the inline style uses a single in-line poppet body. Use the Inline Spring and Barrel Spring filters above to see each set.
What grade of stainless are these?
The inline stainless series is 316 stainless (Midland catalog p.322). The barrel series is cast stainless, which Midland lists as CF8M/CF8 — tell us the size and we'll confirm the grade with the manufacturer before you order.
Source: Midland Industries Master Catalog 2023, pp.322–323. Ratings are manufacturer values scoped to the family named; confirm the specification for your exact model on its product page.
Related check valves
Ratings, seals, connections, and sizes vary by model; confirm the specification on the product page.
What is grouped here
This collection is organized around the spring mechanism rather than a single application. It brings together the brass spring checks, the stainless barrel-spring and inline spring styles, and the PVC spring-loaded inline valves.
Choosing a spring check
This collection is grouped by closing mechanism. To match a compact inline check valve by size and connection, see our inline check valves collection. Ask us to confirm the seal and rating for your service before you order — email sales@apexflowsolutions.com.