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Last year I built and installed an ambient pressure booster onto our RIX 4VX 24CFM compressor intake, effectively doubling the compressor's output to 48CFM. Now, I'm in the process of valuing assets and am looking for a price on a commercially available equivalent. My Google FU must be weak today, cuz I can't even find a reference to such a device.
"Equality of opportunity or equality of outcome?
One is consistent with a free people and the other requires a police state. Pick one." ~Cool Hardware52
I, alone, am responsible for my health and safety, my actions and inactions.
"If a small thing has the power to make you angry, does that not indicate something about your size?" ~Sydney J. Harris
No, nothing like that. It boosts intake pressure from 1atm to two before it hits the first stage and sits between the intake filter and Nitrox stick. I've never seen one, so I can't even tell you what they look like.
"Equality of opportunity or equality of outcome?
One is consistent with a free people and the other requires a police state. Pick one." ~Cool Hardware52
I, alone, am responsible for my health and safety, my actions and inactions.
"If a small thing has the power to make you angry, does that not indicate something about your size?" ~Sydney J. Harris
To be frank this is something divers in general should not attempt unless they understand fully the principles and applications. But IMHO its a non flyer from the start.
The performance parameters of each compressor is written on a data plate.
Written on it are the diameters of each of your pistons in inches then the stroke
Under this is the RPM of the compressor
Two other important factors also are: Inlet pressure
and: Discharge/Outlet pressure
There should also be the full model number
You need to disclose all this before anyone can proceed.
Rix 4VX 24CFM is just not enough information. Iain Middlebrook
Last edited by iain/hsm; December 7th, 2011 at 06:28 AM.
In most cases, an air compressor is designed to start with atmospheric pressure and then through stages increase the pressure to some known output pressure.
The design takes into account the amount of cooling between stages and the hp requirements to provide a balanced 1st ,2nd, 3rd. and 4th stage so the pressure on the crank shaft is evenly distributed. IF you consider a car engine with 3 each 3 inch diameter pistons moving 3 inch stroke, and then make the 4th piston 4 inch in diameter with a 3 inch stroke you are going to have something come apart rather quickly.
In a 4 stage compressor, each piston gets successive smaller with the same stroke length to keep the pressure on the crankshaft exactly equal and the unit in "balance". Also the cooling fins are designed to bleed off the excess temperature between cylinders.
IF you increase the intake pressure from 1 atmosphere to 2 atmospheres you have doubled the volume of the first stage and now the HP to pump this increased volume must also be increased considerably. With the increased volume also comes much greater heat of compression and the cooling surface of the inter-coolers is now "not sufficient" and the compressor overheats.
In the Walter Kidde compressors manufactured for the military - some had pressurized inlets to compensate for lower atmospheric pressure at high altitudes. They also had longer cooling coils to reduce the excess heat between stages.
Many years ago I attempted to increase the compressor output by pressurizing the inlet and ONLY succeeded in burning up motors and compressors. The most I could get away with - was adding 2-3 PSI to the inlet cover and the results were not worth the minimum benefit.
No big bloody calculations needed to determine what you might get away with.
Jim Shelden
The real reason the maths is difficult is because you lot are still working with that antiquated pounds per square inch nonsense. Add to that all rod loads in foot/ pounds and to cap it off temperature in degrees fahrenheit.
Then you add all your motor calc's are to be done in horse power!!
Give me strength, I bet gas blending for you guy's is a breeze.
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