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. Ratings, seals, connections, and sizes vary by model; confirm the specification on the product page.
Choose your spring check valve
A spring returns the disc to its seat, so the valve closes on flow stop without relying on gravity. Start with the mechanism, or jump to a body material. Each card filters the grid below.
By spring style
- Inline SpringIn-line poppet body; brass, 316 stainless and PVC
- Barrel Spring2-piece barrel body; stainless, 1/4–2 in.
By body material
Ratings, seals, connections and sizes vary by model — confirm the specification on the product page. New to spring checks? See the notes and guides below the grid.
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, so it seats in any orientation rather than depending on gravity like a swing check. 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.321), 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.322), 1/4 in. to 2 in., NBR seat. Some sizes are cast 316 (CF8M) and some cast 304 (CF8); confirm the grade for a specific size with us.
- PVC inline spring — spring-loaded plastic inline body, threaded, for corrosion service.
Verified 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.
| Family | Working pressure | Other verified specs |
|---|---|---|
| Brass inline spring | 500 PSI | NBR or Viton seal (per model) |
| 316 stainless inline spring | 1500 PSI | Opening (cracking) pressure 2–3 PSI; -10 to 150°C; medium W.O.G. (catalog p.321) |
| Stainless barrel spring | 300 PSI | Opening pressure 2 PSI; -10 to 120°C; NBR seat (catalog p.322) |
| PVC inline spring | 150 PSI | Threaded ends |
Choosing
Match the body material to your media and the connection to your line: FNPT×FNPT to sit between two female ports, or MNPT×FNPT to thread directly onto a male end. On brass models the seal (NBR vs Viton) is the other decision — compare them in the Buna vs. Viton overview. A spring check seats without gravity, so it suits vertical or angled runs where a swing check won't; the swing vs. spring guide covers when to use each. For sizing and connection across all check types, see the check valve selection guide. Confirm chemical, pressure and temperature suitability for your service with us and the manufacturer before ordering.
Frequently asked questions
Does a spring check valve work in any orientation?
A spring returns the disc to its seat rather than relying on gravity, so spring checks are commonly used in vertical and angled runs as well as horizontal. 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.322) 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.321). The barrel series is cast stainless (CF8M/CF8) and the grade varies by size — tell us the size and we'll confirm with the manufacturer before you order.
Source: Midland Industries Master Catalog 2023, pp.321–322. Ratings are manufacturer values scoped to the family named; confirm the specification for your exact model on its product page.
Related check valves
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
A spring check closes without relying on gravity, so it is often used where a swing check will not sit correctly. Compare the two on the swing vs. spring guide, and see the check valve selection guide to match size and connection. For seal materials, the Buna vs. Viton overview compares the elastomers. Confirm the seal and rating for your media against the manufacturer data — email sales@apexflowsolutions.com.