Screw Compressor Specifications

Screw Compressor Specs - A screw compressor moves liquids or gases, usually uphill but also sideways and downhill, with efficiency. It is capable of pumping dirty liquids with pockets of vapors and will pump very viscous liquids. The design is complicated, expensive and heavy, but screw pumps are robust and dependable.

Pumps and Principles
There are two types of pumps. One kind creates a vacuum and allows air pressure to push a liquid or gas into a new location. The second kind, called a positive displacement pump, picks up a liquid or gas and carries it to a new location. The pressure of the air in our atmosphere limits the amount of work the first kind can do. The positive displacement pump is limited only by the strength of the metal its made of.

How It Works
The screw compressor has two interlocking screws with spaces between the thread. Picture a common bolt with thick threads and no head. Make the threads thinner so that each turn of thread has a space between it and the thread above and below. Put a matching bolt next to it, held in place so that the threads touch closely all along its length. Put a casing around both bolts that touches the threads for the length of the bolt except in the middle where the bolts touch. Any liquid or gas present at the intake end of the two bolts will be drawn into the space between the threads and carried up the length of the bolts and pushed out the other end. The threads inside the screw compressor are designed so that they become thicker toward the outlet, compressing the liquid or gas trapped inside the threads. Some screw compressors use a lubricant which cools the screws, lubricates the mechanisms and aids in compression.

Specifications
The U.S. Department of Energy suggests that each screw compressor be rated for its maximum capacity at full load, the pressure it generates at full load, the horsepower and efficiency of the motor driving it, the horsepower and efficiency of the fan assembly that cools the entire unit, the power requirements of the entire unit including the motor driving the twin screws, the fan motor and the efficiency of the entire unit under full, load, partial load and no load situations.

Uses
Car engines use a screw compressor -- which in this application is called a supercharger -- to compress air and push it into the combustion chamber. The supercharger gets its power from a belt driven by the engine itself. It takes horsepower to run the compressor, but the increased fuel and air mixture inside the combustion chamber more than make up for the loss, delivering a 40-percent net increase in horsepower. Industry uses screw compressors to provide compressed air, often building the screw compressor into a trailer for remote applications. Any industrial use which encounters a liquid mixed with solids or air pockets, such as municipal water and sewage systems, can use a screw compressor. { source-ehow.com }

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