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low pressure air

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weatherbird

Mechanical
Sep 17, 2007
8
I need to test some equipment that I am building, and to do so, I need to use air at 2 to 14 oz of pressure. I also need to be able to control and measure that air pressure. What is the best and cheapest way to acheive this. I have looked into regulating compressed air, but can't find exactly what I need. All suggestions would be appreciated. Thanks.
 
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Measuring can be done with a manometer, either digital or water gage. As for controlling, that will depend on flow and volume. There are many ways to control, depending on size of orifice or opening, flow, volume, allowed back pressure, etc.
 
is this gage or absolute?

Tobalcane
"If you avoid failure, you also avoid success."
 
It is guage pressure. This pressure is being put to a 3/4" port on my device. Is it possible to reduced compressed air down to these pressures without high dollar regulators?
 
What is the device volume? What is the expected outflow rate? (as asked by Ron above) How precisely do you need to control the pressure? Do you need to set the pressure immediately, or can you control based on your manometer reading?

I'm picturing a fan blowing into a duct with a sliding gate on the side of the duct. Read your pressure with a water manometer. Open the sliding gate to reduce pressure, close it to increase. You can build this setup with liquor store cardboard and $2.95 worth of duct tape.

-handleman, CSWP (The new, easy test)
 
A small aquarium pump, bubbling into an inverted jar or other container that is immersed in water or other liquid. Adjust depth of jar mouth to adjust pressure. As long as bubbles come out of the jar, the pressure in the jar will be constant, and very precisely known (as long as you know the sp. grav. of the fluid). If saturated air will give trouble with your device, use oil or some other liquid.
 
Interesting that all responses ignor that pressure can not be "oz" whichis force (or mass). It has to be oz to square inch (forCe/area).
 
You're right, israel, I know I'm guilty of using "pounds" for pressure as a shorthand for psi, but it can be confusing to people not familiar with it.
 
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