What are the Cracking Pressures for SVC/SHC Sanitary Check Valves?

We were recently asked what cracking pressures are available with our SVC/SHC springless sanitary check valves and if they are designed for gases.

Well, yes they are, they’re designed for both gases and liquid applications.

Cracking Pressures for SVC/SHC Sanitary Check Valves by Disk Type

As listed in our data sheet check valve cracking pressures are as follows,

Polymer Disk (Teflon or PEEK)

• Cracking Pressure: 2.76 millibar (~0.4 psid)

316 Solid Disk or 316 Disk with EPDM Soft Seal

• Cracking Pressure: 8.96 millibar (~0.13 psid)

Note that we don’t list a cracking pressure for check valve with a polypropylene disk. It actually would be about the same as the polymer disk but we don’t list it because that particular disk is only used in liquid down-flow applications. So that disk is open at all times and the only time it will close is if the water raises in the drain causing the buoyant disc to rise into the seat and close off.

So as long as you have a water based liquid for the SVC down flow application, you will be fine.

FAQ

What is Cracking Pressure in Check Valve

Cracking pressure in a check valve is the minimum upstream pressure required to slightly open the valve and allow flow to begin. Below this pressure, the check valve remains closed, preventing any reverse or forward flow depending on the design.