The optimal siting of the compressor in the compressor room is a necessary condition for meeting optimal operating conditions. It must be realised that e.g. an increase of the operating temperature with a screw compressor above the recommended operating temperature by 3 °C represents a loss of output of about 1 %. This increase of temperature shows not only in the performance of the compressor, but also in its service life and not least in the consumption of electrical energy.
General basic principles for siting the compressor
The basic general principles for siting the compressor are only of an informative nature and in no case replace the specific conditions for siting, operation, handling and maintenance of the given compressor specified in the particular warranty documentation (operating manual etc.) supplied by the manufacturer of the given machine!
In general the following rules apply:
- The place for siting the compressor must be sufficiently ventilated. The ambient temperature must not be higher than 35°C.
- A sufficient distance from the wall must be ensured, at least 1 m. This is important for the supply of cooling air, maintenance and operation.
- The compressor must stand on a level surface. No special base is necessary.
- Between the compressor and the air receiver a ball valve must be installed (if it is not already part of the delivery). The minimum diameter of the main line in the compressed air network is governed by the data in the relevant operating manual.
- Before putting into operation, or after work on the equipment, the correctness of the direction of rotation of the motor must be checked.
- As regards the combination of a screw compressor with a piston one, care must be taken that both compressors have a separate supply to the air receiver.
- A compressor station consisting of a horizontal or vertical air receiver on which the compressor is firmly mounted can be sited without any foundation. A resilient siting is achieved simply by means of about 5 mm thick pads of medium-hard rubber under the feet and under the nuts of the foundation bolts. Floating foundations are not necessary.
- When connecting the station to a fixed line it is recommended to place between the shut-off valve of the air receiver and the compressed air network an elastic hose about 0,5 m long.
- Compressors, especially medium and larger ones, should be placed in a separate room. This room must be clean, dust-free, dry and cool. If possible, it is recommended to choose the north side of the building here and to remove heat-radiating appliances from the room or to insulate them very well. In order to prevent damage as a result of frost or corrosion from strong condensate formation, the temperature in the room should not fall below + 5 °C. It is therefore recommended to provide the air supply openings with adjustable louvres for constant compensation of fluctuations of the outside temperature according to the seasons. It is also necessary to ensure good accessibility and lighting for carrying out maintenance.
- Air-cooled compressors require a sufficient flow of cooling air. The temperature in the room should not exceed 35 °C. Up to a power input of 15 kW natural ventilation is as a rule sufficient. With larger compressors or smaller operating rooms artificial ventilation with a fan built into the air outlet opening is necessary.
It is recommended to place the compressor near the air supply opening so that its fan draws the cooling air directly from the opening. Because warm air rises upwards, the opening for the air outlet is placed in the ceiling or on the wall just below the ceiling. At the same time it must be realised that e.g. an open door into the room often brings no additional cooling for the compressor, because the air flowing in through the door flows by the shortest route to the outlet opening without reaching the compressor in any way.
The air supply opening must, with regard to the louvres, grilles and the like used, be made proportionally larger than the air outlet opening.
Ventilation of the compressor room
It takes place in several ways:
- natural cooling of the compressor room - the air supply opening is the same as the air outlet opening;
- artificial cooling of the compressor room - a fan is built into the air outlet opening
- artificial cooling with outlet to the outside - for intake temperatures above 0 °C without an outlet flap, with an outlet flap in winter operation. In order to prevent freezing at intake temperatures below 0 °C, warm air can be mixed into the cold intake air
- air outlet for heating (recuperation - heat recovery) for the use of waste heat.
Operation of a station with several compressors
If several compressors are placed in one room, two possibilities for cooling present themselves.
We can add up the power inputs of the compressors and proceed as if a corresponding single large compressor were placed in the room. When siting the compressors care must be taken that the air stream coming out of the fan of one compressor is not aimed at the aggregate of the next compressor - the fan of the next compressor would then draw in precisely the heated air and the affected compressor would be poorly cooled.
A better solution is - if it is structurally possible - to create for each compressor a corresponding air supply opening. As an air outlet one large opening is sufficient, which corresponds to the sum of the air supply openings, i.e. that it is comparable with them in the size of the area. To find out the size of the individual air supply openings, the power inputs of the individual compressors are added up and accordingly the cooling air flow and the necessary air supply opening for the installed total output are calculated (corresponds to the air outlet opening). The area calculated in this way is now divided proportionally according to the individual outputs, so that each compressor will have an air supply opening corresponding to its size.
If you are considering the purchase of a new compressor or the extension of an existing compressor station, from experience we recommend devoting great attention to the conditions in which the compressors are operated. Believe us that it pays off and in the future it will save you many worries and unnecessarily spent funds.