Restriction Orifices Installation

For what purpose?When you do not specify in detail, the orifice in my vien supplying blood to my brain restricts the blood flow from the upsteam to the downsteam and diminishes my power of thinking to answer your question.

Oh dear.... another information packed question...

We are commissioning a main filtered water system for a blast furnace's refrigeration in Argentina. During the tests two restriction orifices had severous cavitation problems.

We re-cheked orifices calculation with instrucalc moving process variables to critical operation but the flow remained estable and no warnig was present in the program.

RO's are installed in 20" lines at 1 diameter from an elbow downstream each one, we suspect that tey're in a wrong position but we haven't standards to support it.

Does anybody knows if restriction orifices has the same installation treatment that orifices plates?

What is the pressure and temperature of the water downstream of the the orifice?

Higher temperatures and lower pressures will tend to cause problems. Depending on velocity, being too close to an elbow could also cause problems of course.

Does the restriction orifice have sufficiently long tapered sections on both sides of the minimum diameter?

Too sudden an enlargement can produce cavitation.

Here's process conditions:

Inlet pressure: 59.7 PSIG to 102.4 PSIG

Outlet pressure: 17.06 PSIG to 24.17 PSIG

Flow max.: 660430 Gallon/hour

Flow min.: 237754 Gallon/hour

Temperature: 86°F to 104°F

Bore diameter:8.02"

Cavitation starts close maximun pressure and flow that's the normal operation conditions.

valvactur:

Understanding that sitting here, I cannot give an exact answer but only general guidance/comments on your question based on the information you present, I offer the following:

The ratio of absolute outlet pressures don't conform to the other min/max parameters of absolute inlet pressures and flow. The outlet pressure at max flow seems way too low (or, the pressure at min flow is way too high).

Can you describe the geometry leading to and from the restriction, how and where you are taking your measurements, and what is downstream of the restriction outlet?

there are no requirements. A restriction orifice does not require recovery, it is dealing with the actual pressure loss.

Jack Beadling

auguastaeng.com