Please check my thinking

etpm · 2014-02-13T16:55:04+00:00

I want to calibrate several pressure guages. These are low pressure gauges, mostly 15 PSI max but a few up to 200 PSI. So I want to make a chamber that the gauges screw into and is filled with water. To pressurize I will have a tube sticking straight up with an ID just a little over the size that would make an area of .1 square inch. Then I will use a piston with a cross sectional area of exactly .1 square inch to pressurize the chamber. The little amount of water that leaks out past the piston will provide the seal. I don't want to use a lip seal because it will have a little drag. My thinking is that the piston, not the tube, needs to be exactly .1 square inch. If I used a lip seal then the tube would need to be exactly .1 square inch. Is my thinking on this correct? I will be using a lever of some sort to apply pressure to the piston. I want to use the small diameter piston to reduce the weight I will need to apply to the piston. Thanks, Eric