The diaphragm compressor
This variant is also used as an airbrush compressor.
Mode of action of this type of airbrush compressor
It’s usually a little louder than piston compressors, which has to do simply with the fact that the compression is done by a mechanical part, which is more capable of getting into audible resonance than the piston of the other compressor group which is just a flat membrane. This part usually consists of an elastic material (plastic or metal) which is moved up and down by an electric motor, so that the medium air is compressed. This air can be taken then through valves, located behind the actual compressor’s mechanism.
Commonly for this compressor technology, no tank is usually used for an intermediate storage of the air. The device thus runs without pause. This leads to heat, which is usually measured by corresponding sensors. In case of overheating, the driving electric motor is switched off until an acceptable temperature has reached. This is always some degree under a so-called hysteresis level. This causes the device to switch off again not after a short time, but after a certain running period. Often, in addition to the diaphragm, a ventilation system is also driven by the electric motor, which provides the necessary cooling. This increases the lifetime of the electrical unit as well as the run-time between the automatic shutdowns. So, depending on the outside temperature, the airbrush compressor is also able to supply air without even shutting down.
Diaphragm compressors are oil-free in most cases. Therefore there is no need for maintenance. Depending on the price range, the focus is on the lifetime of the membrane. Should this be defective (assuming normal wear), the only way is to take it to the workshop. Only very few models are suitable for an adequate, professional DIY repair.
As the price of an airbrush compressor of this type is quite affordable, in case of a defect, it makes sense to estimate whether the costs of a repair are reasonable in relation to buying a new device. Finally, the models are constantly being developed and, should the defect occur several years after the warranty period, a new buy would be worth considering, if only for the higher efficiency of a newer model.
- low cost
- compact and portable, since usually without air tank
- (mostly) maintenance-free, as no oiling circuit takes place
- somewhat louder than piston compressors in the same performance range
- runs (almost) permanently
- depending on the design, thermal shutdown (older models)
- lifetime of the membrane is the weakest point of this type of airbrush compressor
- air flow is not perfectly uniform, as there is no caching
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