DP across the orifice

[Dave W]

What Dp across the orifice do you recommend using ? Does the higher the depression have an advantage or just preference for orifice sizing.

Dave

[49-1183904562]

Dave,

A little more information would help.

What test depression are you planning on using?
How much power do you have in your bench? Motors Etc.
Are you planning water gauges or electronic?
How sensitive do you what your bench to be?
What is your expected max flow requirement?

This should help.

Rick

[Dave W]

[larrycavan]

[Tony]

[bruce]

I'll second what Tony is saying, I can confirm this while working with the water gages on my bench build. Higher Dp makes the gages more stable. I've been working with 6" but plan on doing some tests this coming week with a tad higher Dp's for comparison.

[larrycavan]

That 1-2 CFM difference between the smaller and larger ranges, at the same valve lift, is very normal with analog guages. Actually, you're bench appears to be working very well.

I also agree 100% with what Tony said.



Edited By larrycavan on 1204511134

[SWR]

[106-1194218389]

So if I follow correctly, the way to basically change the Dp across the orifice is just to change the slope on the inclined manometer and calibrate the orifices for that WC as in 12" rise compared to a 6" rise. Am I correct in assuming that?

[thomasvaught-1]

Quote:

"So if I follow correctly, the way to basically change the Dp across the orifice is just to change the slope on the inclined manometer and calibrate the orifices for that WC as in 12" rise compared to a 6" rise. Am I correct in assuming that?"

Agree, then your flow will go up 41% higher for the same orifice size. Raising the DP to 13.5 from 6" makes the flow change from 300 cfm (for example) to 450 cfm. A 50% increase.

Tom V.

[Tony]

[106-1194218389]

I really appreciate all the input, this stuff is really starting to make sense.