Unknown C1 and CV of Valve 1

[francitj]

We have several different applications for piston and swing style check valves. The valves we purchased came with a cracking pressure provided by the manufacturer but no C1 and CV values, or any values for when the valve is cracked to full open and we need to calculate the flow through these valves. Should we find similar valves and use those C1 and CV values or is there a better way to estimate these values?

 

[tr1ntx]

Yes, try to find similar valves with available information. The good companies have actual test data based values. A lot of the smaller companies simply copy that, and usually "enhance" it.

 

[gerhardl]

Ditto, and you are probably already aware of perhaps the main reason for calculating check valves: to avoid too large checkvalves resulting in high pressure loss and possibly 'gulping' through the valve with ditto slamming and possible waterhammer (especially for the swing-checkvalves types with no forced (spring assisted) closing).

If this is the case, a piston type could be better, or other types soft-closing checkvalves.

Commercial available check-valves varies enormously in quality and lifetime for else 'equal' types.

Another way of checking is to have a look at the flow velocity through the valve at high and low flow values: the velocity should be 'sensible' and within normal flow velocities,

Some types of check valves will work good at high velocities,higher than normal for valves, nozzle check valves for instance, but no type would perform at the best part of the curve, at (more extreme) lower velocities, and will often give other problems as described above.

You will also get other hints searching the forums for C1.

See for instance thread1203.205528

 

[grockj]

You could always test them.
Knowing:
1) Specific gravity of your media
Observing:
1) inlet pressure
2) outlet pressure
3) flow through valve
4) temperature

You can calculate for these values

although maybe I should assume that since you need to calculate these values you have no way to test them in any simple manner.

good luck!