SAE flange check valves to ISO 6162‑1 & ISO 6162‑2, 1/2" to 2"

They are the two SAE flange patterns. ISO 6162-1 is the 21 MPa (3000 psi) interface, known as SAE Code 61, and ISO 6162-2 the 42 MPa (6000 psi) one, Code 62. They share a nominal size but not a bolt spacing: at DN15 the centres are 17.5 by 38.1 mm on the 210 series and 18.2 by 40.5 mm on the 420. So the two do not interchange, and the 420 valve is physically larger and heavier at the same bore. Every size of the RVZ-SAE is made in both classes.

One check valve, two O-rings and two holding plates. That is MHA's stated scope of delivery. The adapter plate is not included and has to be ordered separately, and neither are the flange halves, bolts and washers on the mating side. The commonest short order on this product is the adapter plate, so if your layout needs one it is worth putting on the same purchase order.

It is a flanged steel spacer that lets you stack the check valve against another flanged component — MHA's own example is a KHZ ball valve. The real benefit is maintenance: with the adapter plate in the stack you can remove the other component without taking the check valve out. Plates are listed for DN20 to DN50 in the 21 MPa class, 29 or 33 mm thick, and DN15 is on request.

Flow is B to A and there is a large arrow on the body pointing the direction flow is allowed to pass — from your pressure source towards the load. Fitted the wrong way round it blocks the line rather than protecting it. The bolt pattern will stop you fitting the wrong class of valve, but nothing stops you fitting the right one backwards, so check the arrow before the bolts go in. Vertical and horizontal both work.

Standard is 0.2 MPa, which is 2 bar, on every size and in both classes. Other opening pressures are available to order, but not adjustable afterwards — it is a spring inside a closed body. Note also that spring and machining tolerances mean the actual figure can sit roughly 30 percent either side of nominal, so if your circuit needs it held tighter than that, say so at enquiry.

Because they are usually doing different jobs. A threaded RV is often just stopping backflow, so the lightest spring that reliably reseats is best — every extra bar of cracking pressure is permanent pressure drop. The flange-mounted RVZ is more often holding a load on a cylinder or an accumulator, where a firmer spring gives a more definite reseat. If the 2 bar is costing you too much drop, ask about a lighter spring.

It depends on what the valve is bolting to. MHA builds four versions: Option A without seals, Option B with the inlet side sealed, Option C with the outlet side sealed, and Option D with both sides sealed. Where both mating parts already have their own O-ring grooves you want A; where the valve sits between two flat faces you want D. There is also Option E with threaded holes, on request. It is a build choice, so it belongs in the enquiry.

Yes — an orifice can be drilled through the poppet, which gives a deliberate restricted back flow instead of a hard shut. It is used where a locked cylinder has to bleed down in a controlled way rather than staying locked. It has to be specified with the order, since it means machining the poppet, and it cannot be added on site.

No. Unlike the threaded RV — where the stainless body is capped at 350 bar against 500 for the steel — the RVZ-SAE is limited by its flange class rather than the body metal, so 210 is 210 bar and 420 is 420 bar in either material. Code 28p8 is the steel build and 44p8 the SS316 one; the seat, the O-rings and the temperature range are the same in both.

Body and poppet in steel or stainless SS316, a polyurethane seat and FPM (Viton) O-rings as standard, rated minus 20 to plus 100 degrees C. The Viton is worth noting — it gives a wider fluid and temperature range than a nitrile-sealed valve. The polyurethane seat is a soft seat, which is why this valve holds a load better than a metal-to-metal poppet does.

No. The bore is identical in both classes — 11 mm at DN15 rising to 37 mm at DN50 — so moving up a class buys pressure capability and a larger, heavier body, not flow. If you need more flow, go up a bore size. If you need more pressure at the same flow, go up a class.

Read the flat of the body. It carries the country and date, the maker's reference, then RVZ-DN20-SAE420 style type, bore and class, then a line giving the rating, material code and cracking pressure, and finally a works order number that ends in MHA's own catalogue order number. A photograph of that marking is enough for us to quote the identical valve. What the marking does not show is which faces were built sealed — check the faces for O-ring grooves.

MHA batch tests to DIN EN 12266-1 using methods P10, P11 and P12 — body strength at 1.5 times rated pressure, body tightness, and seat tightness across the closed poppet. The heat numbers appear in the test report, so a valve can be tied back to its paperwork. Project-specific testing and documentation is available on request; ask with the order rather than afterwards.

Usually it does not need to be. The commonest cause of a check valve passing is debris trapped on the seat, so the first move is to flush the line and inspect rather than to condemn the valve. Beyond that there is no service kit for these bodies and replacement is the practical answer — but a damaged O-ring or a scored flange face is a separate and much cheaper problem, so check those first.