What does a compressor do? A compressor is a device used to increase the rate of which air is able to flow through a system (such as a vehicle's carburetor, or a bicycle's crank-braking mechanism). The flow of air depends on a number of factors, including the pressure that the compressed air exerts against the walls of the system (the "piston" or "drum") and the speed at which it is compressed. Some common types of compressors are rotary screw compressors, which have their own screw-like mechanisms for compressing air; screw pumps, which use a similar mechanism to screw pumps; and centrifugal-cooled compressors, which use a combination of these two pumping mechanisms.
Why might I need to use a compressor? Depending on the application, there are many different scenarios in which a compressor might come in handy. Air compressors, for example, are used in many businesses and industries to increase the efficiency by which air is moved from one location to another, as well as to decrease the amount of noise pollution and vibration caused by moving air. They can also reduce or eliminate the amount of heat build-up inside vehicles and other enclosed spaces. There are even some medical applications to which compressors are used, as they can reduce airway pressures that are too high or that result from tissue damage. And with an economy that is currently facing many problems, many manufacturers of vehicles are looking to improve fuel efficiencies by using less fuel (an increase in efficiency), which also means reduced greenhouse gas emissions.
How does a compressor decide what speed to compress? The speed at which the compressor starts up is determined by the threshold value (the unit in which the air pressure is measured) and the maximum reading on the gauge. When the threshold value is reached, the air flow stops and the machine is not allowed to keep operating. At a low enough threshold, the engine will not be able to maintain its RPM (Resonator Speed Routine) so will not work properly.
Most compressors have digital controls that allow them to set the threshold and the maximum reading for the air flow. Digital controls are typically less sensitive than stick-type controls, and have a higher success rate over time. This means that they allow more changes for users than stick compressors (as well as being easier to change if you ever need to). In fact, some compressors have separate threshold and maximum controls, so that a user can fine-tune the speed of the compression to compensate for the amount of oil in the system, or other environmental factors.
Mixers are used to mix the compressed air with freer flowing air to create a constant flow of air that does not increase the threshold or reduce the RPM of the machine. A motor driving a mixer is often included in the compressor, although separate motor controls can also be installed if more power is needed. Mixers can be used to increase the overall volume of the air, which improves the efficiency of the system. They often work on a variety of voltages and speeds to accommodate the needs of any given job.
Auto-return (or open air) compressors open the valve so that the pressure inside the tank can automatically return to normal. This saves time during the startup phase of many compressors. However, these are not the most efficient systems. In order to conserve space and increase efficiency, they often have separate fan motor controls that control the speed of the fan, which also controls the pressure of the air that is returned to the tank. In addition, many compressors have built-in temperature or pressure sensors, which tell the compressor when the tank is too hot, or has too much pressure, and shuts the valve so that the pressure is balanced once again. These features are very helpful, but if you really need an auto-return system, it is often worthwhile to spend the extra money and get one of the better systems that does not have these additional features.
Higher volume compressors usually have more features than lower volume compressors, including automatic flow control and shutoff. The volume knob controls the flow of air into the tank so that the compressor maintains the proper pressure without blowing more air than is necessary. Higher volume compressors can shut off at a lower volume level than lower volume compressors, which improve both energy efficiency and noise reduction. Most of these compressors also have separate speed controls for fast speed and slow speed operation. Although quiet, these compressors still have to use more energy than the silent compressors, so unless you want a quiet compressor that never reaches over limit, it is probably a good idea to go with a higher volume compressor.
When you have a job that calls for a high gain, the best way to go about increasing the gain is by compressing more air. That's where the compressor comes into play. A gain reduction orifice value tells the unit how much more air must be compressed to move the same volume of gas through the pipe or line. This value varies according to the type of compression being used - some are based on volume while others use a ratio of gain reduction to output pressure.