mini air compressor
mini air compressor
(OP)
For an application, a very small air compressor is needed. The compressor need to supply 80 to 100 psi of air at a flow rate of only 0.1 scfm. The correspond to about 1/10 horsepower.
Lightweight and compactness is important. Are there air compressors on the market with that small of an output?
Thanks
Lightweight and compactness is important. Are there air compressors on the market with that small of an output?
Thanks





RE: mini air compressor
RE: mini air compressor
RE: mini air compressor
RE: mini air compressor
RE: mini air compressor
http://www.medousa.com/en/
RE: mini air compressor
RE: mini air compressor
RE: mini air compressor
Thanks
RE: mini air compressor
David
RE: mini air compressor
I understand when compressing air, work is done to it which increase the temperature. But most of this work is done to compress the air, just like compressing a spring, which adds to the potential energy of air. But how much is converted into heat?
For the application, I just need a source of 80 psi air with a flow rate of 0.2 scfm. As you see, the flow rate needed is not much. But temperature is important. It cannot be too much higher than ambient.
For the given pressure and flow rate required, is there an easy way to calculate the temperature rise of the output air?
Is the output air hot right from the start or does it get hot only after some time of use...?
Thanks
RE: mini air compressor
http://en.wikipedia.org/wiki/Ideal_gas_law
And bloody Hell, so does Mr Carnot.
http://en.wikipedia.org/wiki/Carnot_cycle
Well, you do have a lot of important people to see, and things to learn.
Cheers
Greg Locock
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
RE: mini air compressor
Since diving tanks are filled to 3000 psi, doesn't the air gets really cold when it get released? Shouldn't it cause frostbite to diver?
Or does the temperature of the released air actually depend on the rate at which it is released?
In another word, if a gas at a higher pressure is released through an orifice to a lower pressure, is the temperature drop fixed or does it depend on the rate at which it is released (which I'm assuming which depend on the size of the orifice)? Thanks
RE: mini air compressor
It has been many years since my process courses in university but I will try and remember some of the details. In compression of a gas the reduction in volume results in and increase in pressure and temperature to maintain the same entropy(I believe). This increase in temperature is quickly dissipated when the compressor is cold as the quantity of heat contained in a gas is small. As the compressor heats up (heat capacity of cylinder and piston) more of the heat will remain in the compressed gas.
Upon reduction in pressure (expansion) the gas does indeed cool down. To remain at ambient temperature the gas absorbs heat from the surroundings. In the case of your diving example the quantity of heat in the water easily provides the heat to keep the gas breathed by the diver at the temperature of the surrounding environment. The theoretical temperature drop would be related the the inlet and outlet temperature. From the practical perspective it depends upon the rate at which it is released as the transfer of heat is time dependant so the slower the release the less noticible the pressure drop.
RE: mini air compressor
you said, "In compression of a gas the reduction in volume results in and increase in pressure and temperature to maintain the same entropy(I believe). This increase in temperature is quickly dissipated when the compressor is cold as the quantity of heat contained in a gas is small. As the compressor heats up (heat capacity of cylinder and piston) more of the heat will remain in the compressed gas.
"
I guess this is what I'm trying to get all along. I'm trying to get a mini air compressor to give me a small flow rate of compressed air. But I want the temperature of the compressed air to be not much higher than ambient.
I wonder if it's possible to design some kind of aftercooler (maybe with coils and a fan) that can quickly cool down any heating due to compression virtually instantaneously.
RE: mini air compressor
RE: mini air compressor
RE: mini air compressor
RE: mini air compressor
The thing need to be portable (by a normal human) and not too heavy. It needs to output cold air for at least 5 minute. It has to be air and not any dangerous gas.
I want to use a vortex tube. I can either power it with a small compressor that will give me the pressure I need (90psi) and flow rate (0.3 scfm), or use a high pressure accumulator tank.
I prefer the small compressor method. But if I need an instaneously source of cold air, I'm not sure how fast it takes the hot compressed air to cool to a point where it will be close to ambient so that the vortex tube can lower it 80 to 100 F more.
Or I can use a small compressor not to power the device directly but simply fill the air accumulator tank so it can be used later. But to get the amount of air I need, the tank need to be filled to I'm thinking at least 500 psi. Are there any cheap and compact compressors out there that can do 500 psi?
Thanks
RE: mini air compressor