Working Principle Compressor

Working Principle Compressor
Compressor is the engine to compress air or gas. In general usually suck air from the atmosphere, which in physics is a mixture of several gases with a composition of 78% Nitrogren, 21% Oxygen and 1% mixture of Argon, Carbon Dioxide, Steam Water, Oil, and others. But there are also compressor which sucks air / gas with a pressure higher than atmospheric pressure and so-called amplifier (booster). Conversely there is also a compressor that sucks the air / gas pressure lower than atmospheric pressure and is usually called a vacuum pump.


If a gas / air inside a closed room reduced its volume, the gas / air will experience compression. Compressor that uses this principle is called displacement compressor types and working principles can be illustrated as shown below:

image 1 Fluid Compression

Here used piston that moves back and forth by a first mover (prime mover) in a cylinder to suck, compress and remove the air repeatedly. In this case, air can not leak through the gap between the wall of piston with cylinder wall rubbing together. For that is used as a piston ring seals.

If the piston pulled upwards, the pressure in the cylinder below the piston will be negative (less than atmospheric pressure) so that air will enter through the slit valve suction.

Then when the piston is pressed down, the volume of air is trapped below the piston will shrink so that the pressure will rise.


Based on the principle works, compressor consists of 2 (two) types Displacement (piston) as described above and Dynamic (rotary) that draw air through high-speed blade rotation.

AIR COMPRESSION PROCESS

Air compression process that occurs in piston compressors can be explained by using the approach as shown in image 1

Torak start the compression step at the point (1) PV diagram, then move to the left and the compressed air until the pressure rises to the point (2). At this point the pressure in the cylinder reaches the price of Pd is higher pressure than the pressure in the exit pipe (or tank press) so that the exit valve on the cylinder head opens. If the piston continues to move to the left, the air will be pushed out the cylinder at constant pressure for Pd. In point (3) piston reaches top dead point, ie the end point of piston movement in the compression step and expenditure.

image 2 P-V diagram of Compressor

In Figure 3. visible form and arrangement of compressor construction which visually explains that the air entering through the air intake filter smoked by a piston to a point below the maximum. Before entering the air piston within the cartel simultaneously sucked through a vacuum pipe, so it is not the vacuum in the cartel. Then a vacuum in the cylinder air out through the vacuum pipe.

image 3 Cuts Across Compressor Torak

Condensation of water vapor

The air is sucked and compressed in the compressor will contain water vapor in sufficient quantities large. If the steam is cooled air discharged from the compressor, the vapor will condense into water. This water will carry over to the machine / equipment is using it and cause disturbances in lubrication, corrosion and water hammer events in the piping system.


Aftercooler is a heat-exchanger that is useful to cool the air / gas compressor output to dispose of unwanted water vapor before it is sent to another device. Water vapor is separated from air by cooling with water or oil coolers. Ingersoll-Rand [--]. Source Can be seen in the image below:

image 4 Multi-Stage Compressor aftercooler

CONDENSATE DRAIN VALVE

Condensate drain valve is part of the compressor which serves to remove condensate (water vapor) that occur during compressor works by taking air from outside, so that air entering the compressed air system to be clean and not cause any water sediment. Another benefit is the hydraulic system, oil remains clean due to contamination of water had been thrown through the Condensate Drain Valve.

image 5 Condensate Drain Valve