JIS 10K SS316 swing check valve, 1/2" to 4"

A swing check valve in 1/2" to 4" (DN15 to DN100), with JIS 10K flange ends and a body in SCS14A Japanese cast stainless with SS316. The gasket is PTFE. Rated JIS 10K for service at not published.

It is a disc on a hinge. Forward flow pushes it open and holds it clear of the bore; when flow stops or reverses, the disc swings shut under its own weight and the backpressure behind it. Nothing operates it — no handle, no stem, no actuator — which makes it the cheapest way to stop a stopped pump being spun backwards, and the least visible when it stops working. How it works, in full.

• Dimensions are published for the 3" and 4" sizes. The catalogue lists part numbers for all eight sizes, so every size can be ordered; dimensions for the other six are quoted per order — tell us the size and we measure a stocked unit.
• ⚠ Take flange drilling from your flange standard, not from a valve table. The 3" figures — flange OD 185 mm, bolt circle 150 mm — are JIS 10K for 80A. The 4" row prints 230 / 190.5 / 157.2 mm, while JIS 10K 100A flange drilling is 210 mm OD on a 175 mm bolt circle — so at 4" confirm the drilling against your mating flange before you order, and we check the valve against a stocked unit.
• What to do instead. Ask us and we will measure a stocked unit — flange OD, bolt circle, face‑to‑face, whichever you need, off the shelf rather than off a datasheet. Send us the flange you have to bolt to and we will confirm the fit before you order.
• No working temperature is published. The gasket is PTFE. If temperature matters to your duty, ask and we will get the figure from the factory.
• The air test is published as 0.4 to 0.7 MPa, a range rather than a single figure.
• SCS14A is the right grade to see here. It is the Japanese cast stainless designation equivalent to CF8M, and using it alongside JIS flanges is at least internally consistent — which is more than can be said for the dimension table.
• ⚠ Fit a Y‑strainer upstream. A flake of scale between disc and seat holds the disc fractionally open, and the valve then passes reverse flow while looking perfectly normal from outside. There is no stem position or indicator to check. A strainer is the single most effective thing you can do for a check valve.
• Orientation is not optional. Flow follows the arrow cast into the body; on a horizontal run the bonnet points up; on a vertical run flow must be upward. Never on downward flow — use a spring check for that. The three rules.

Four angles on the same valve. Photographs of the stocked item, not renders.

The manufacturer’s sectional drawing. The callout numbers correspond to the item numbers in the parts list.

• The disc and the seat face are what wear. Everything else is a casting or a fastener. On a valve that closes every time the pump stops, those two surfaces take the whole duty cycle.
• The hinge pin is the other one to ask about. A disc that chatters — which happens when the valve is oversized for the flow — wears the pin, and a worn pin lets the disc sit crooked on the seat.
• The item numbers are the manufacturer’s, matching the callouts on the drawing above, so a spares order matches the section.
• Everything here is published, not on request. If you need to know what touches your fluid, the whole list is above.

• ⚠ Do not design to these figures. The shell test is roughly twice the nominal rating and exists to prove the casting. The valve is not intended to operate there.
• ⚠ What actually breaks a check valve is not pressure. It is slam on flow reversal and chatter at low flow — both of which happen far below the shell rating. Why a swing disc slams, and when to use something else.
• The published figures across the five variants do not line up. Three of them publish no working temperature at all, one publishes no test table at all, and the two flanged stainless variants give the air test as a range where everything else gives a single figure. All five side by side, with every one flagged.