Compressed air is very useful in construction jobs.

Air compressors are used to provide the power to operate construction tools and equipments. This machine increases the pressure of air by reducing its volume. The air compressors supply the high pressure air that powers the rock drills, pile driving equipment etc.

The energy supplied by the compressed air is most convenient method of operating tools and equipments.

Basic components: air compressor with prime-mover, suction line with air cleaner, intercooler, after coolers, receiver and safety valve.

The air receives the energy from the compressor when it is compressed. This energy is transmitted through a pipe or hose to the operating equipment, where a portion of energy is converted into mechanical work.

Classification:

Positive displacement or Non-positive displacement type:

In positive displacement compressors air is pressurized with a closed space. These are mainly reciprocating or rotary type. In the reciprocating air compressors air is pressurized by a piston in a confined space of a cylinder. Whereas in the rotary air compressor pressurizing is done by the positive action of rotating blades, moving in a casing.

Single stage or Multi stage:

Staging in the air compressors is done for increasing the capacity (i.e. quantity of air) or pressure rating. Volumetric capacity of compressors are increased by compounding the cylinder in parallel whereas the pressure rating is increased by compounding them in series, this is called multi staging.

Portable or Stationary:

Portable air compressors are generally used on construction jobs. These are self powered through prime mover (normally diesel engine). These are mounted on two or four wheel trolleys. These are used where large volumes of air is required for a long period of time.