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Accurate Differential Water Pressure Measurement

Accurate Differential Water Pressure Measurement

Accurate Differential Water Pressure Measurement

(OP)
When measuring differential pressure across a set of heat exchanger tubes in the 3 to 6 psi differential pressure range, what are the best practices to obtain an accurate measurement?

Then when using the information to define and use a Cv value to measure flow what is the typical accuracy that one can expect?

Are there articles and or instrument suppliers guidelines available on this subject?

 

RE: Accurate Differential Water Pressure Measurement

I'm still learning.. so my advice may not be what the more experienced engineers suggest.

I would have a cross on the inlet and outlet feed pipes.
Use 2 identical pressure gauges on the inlet and outlet.  Make sure these gauges read identically, through prior testing, known values etc.  As a backup, if dP is what's really important, i would use a dP pressure gauge connected to the 4th leg on each of those crosses.

You should be able to use some clear tubing, or if it's feasible swagelok tubing and setup your dP gauge across the HX.

This way, you have 2 measurements, that will give you the same result.

RE: Accurate Differential Water Pressure Measurement

Look up Differential Cells as they will give you the information you need.

RE: Accurate Differential Water Pressure Measurement

My previous post should have been look up Differential Pressure Cells.

RE: Accurate Differential Water Pressure Measurement

As you state you want something simple and portable.  here is one of several differential meters from Extech.  Depending on what accuracy you will need these type meters tart at around $175.00  and go up depending on the range and accuracy needed.  There are a number of brands out there it's just that I've used the Extech.
If you want very simple measurements like the old days you could go to a u-tube manometer and have some fun when you blow  mercury allover the area..

http://www.extech.com/instruments/product.asp?catid=15&prodid=
219
 

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