Air equipment, including air starters
We stock and supply air starters and compressors manufactured by Gali, Ingersoll Rand, TDI, and others. We supply spare parts and repair kits for this equipment, and we also offer a repair and reconditioning service. In addition we supply spare parts suitable for Hamworthy, Hatlapa, and Sperre air compressors.
Most vessels are fitted with air compressors which produce compressed air at 30 bar. This air is then stored in cylinders which are kept charged so that air is always available to start the engines when required. On most main engines the air is fed directly into the combustion chamber in order to turn over the engine. On the smaller generators starting is normally achieved with the use of an air starter, the most popular models of which are Gali, Ingersoll Rand and TDI.
According to our experience the only air starter which is capable of operating directly from the 30 bar air supply without a diffuser is the Gali air starter. The result is that the Gali air starter can produce a high power output which it is claimed gives a much greater chance of first time starting.
There are numerous methods of air compression, divided into either positive-displacement or negative-displacement types. Cooling can be achieved by air cooling or water cooling.
Positive displacement air compressors, manufactured by all our suppliers, work by forcing air into a chamber whose volume is reduced to effect the compression. Piston-type air compressors use this principle by pumping air into an air chamber through the use of the constant motion of pistons. They use unidirectional valves to guide air into a chamber where the air is compressed. Rotary screw compressors also use positive displacement compression by matching two helical screws that, when turned guide air into a chamber, the volume of which is reduced as the screws turn. Vane compressors use a slotted rotor with varied blade placement to guide air into a chamber and compress the volume.
Negative-displacement air compressors (which we do not supply) include centrifugal compressors. These devices use centrifugal force generated by a spinning impeller to accelerate and then decelerate captured air, which pressurises it.