1/2 in. 316 Stainless Steel Inline Check Valve
1/2 in. 316 Stainless Steel Inline Check Valve
✓ In stock at the manufacturer — typically ships within 1–2 business days.
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The 1/2 in. 316 stainless steel inline check valve (part 949403) delivers spring-loaded, bubble-tight backflow protection in a 316 stainless steel body. ASTM A351-CF8M investment-cast body, soft PTFE seat, and a dual-guided stem and disc that seats fast at just 1/2 psi cracking pressure. Rated 800 psi WOG and 125 psi WSP saturated steam. Female NPT both ends. Made in Italy.
Technical Specifications
| Manufacturer Part Number (MPN) | 949403 |
| Nominal Size | 1/2 in. |
| Valve Type | Inline check valve (spring-loaded poppet), 316 stainless steel |
| End Connections | Female NPT × Female NPT, ANSI B1.20.1 |
| Pressure Rating | 800 psi WOG |
| Steam Rating | 125 psi WSP saturated steam |
| Temperature Range | Ask us — Midland's published figures differ; we confirm the rating for this model |
| Cracking Pressure | 1/2 psi |
| Body Material | ASTM A351-CF8M (316 SS), investment cast |
| Seat | Soft PTFE — bubble-tight shutoff |
Dimensions
| End-to-End Length | 2.31" |
Materials of Construction
| Body, Center Guide, Disc & End Cap | ASTM A351-CF8M (316 SS) |
| Spring | 316 SS |
| Seat & Gasket | PTFE |
Performance & Testing
- Low 1/2 psi cracking pressure — opens with minimal upstream pressure
- Spring-loaded for fast seating action; perfect seating at both high and low pressure
- Dual-guided stem and disc
- High-capacity flow profile designed to minimize head loss
- 316 stainless (ASTM A351-CF8M) construction
- Install with flow in the direction of the body arrow
Other Sizes in This Series
316 SS Inline Check Valve, 800 WOG, Female NPT (1/4"–2"). Jump to another size or add it straight to your cart:
| Size | Part # |
| 1/4 in. | 949401 |
| 3/8 in. | 949402 |
| 1/2 in. (this page) | 949403 |
| 3/4 in. | 949404 |
| 1 in. | 949405 |
| 1-1/4 in. | 949406 |
| 1-1/2 in. | 949407 |
| 2 in. | 949408 |
Typical Applications
Backflow prevention on water, oil and gas lines and saturated-steam service within the 125 psi WSP rating. For chemical service, ask us — we confirm compatibility with the manufacturer for your media before you order. The 1/2 psi cracking pressure suits low-head gravity and recirculation loops.
Cross-References & Interchange
Replacing another brand's 1/2 in. stainless inline check valve? Match nominal size, end connections, cracking pressure, and pressure rating for a direct fit — or send us your part number and we will confirm the interchange. Water or air service on a budget? The 1/2 in. brass inline check valve (944403) costs less (not lead-free).
Technical Resources
Expert Guides for This Product
- Check Valve Orientation & Installation — flow direction and mounting rules
- Check Valve Sizing Guide — why line size isn't valve size
- Slamming & Water Hammer — causes and fixes
- Check Valve Leaking? — diagnose and fix it
- Check Valve Chattering — the sizing problem nobody checks
- Buna vs. Viton Seats — which elastomer fits your media