![]() ![]() Then the compressed air flows through and cools down nearly to the freezing point.70% of the contained water vapour drops out as condensate In the compressed air which has already flown through the refrigeration dryer cools the newly flowing air.Even if the cooling temperature seems to be OK, the following errors can cause an excessive pressure dew point: However, the display of the cooling temperature alone is not sufficient. A stationary humidity monitor is hitherto only installed in large systems or in particularly important applications. The refrigeration compressed air dryers are monitored in most cases only by a display of the cooling temperature. After that the air is again heated up to room temperature. The excess water vapour condenses and precipitates. In this case, the pressure dew point is also 2 to 5 ☌. Refrigeration dryers cool down the compressed air to approx. ![]() There are different types of compressed air dryers refrigeration dryers or adsorption dryers are the most commonly used ones. Control valves freeze over in winter in unheated halls.Boreholes can clog up from dust being carried.Bubbles are formed during painting and coating processes.Hygroscopic products (spices, sugar etc.) get stuck together during transport by the pneumatic conveyor system.Wich problems may arise in case of too high moisture? In the following please find some of the most occurring samples: In addition to problems with corrosion and the described results the moisture content has direct influence on the quality of the final products. to blocked nozzles, defective control elements and production stops.Įxpensive repairs and short maintenance intervals are inevitable. The rust gradually chips off and moves to the sampling points. In the course of time, high moisture will lead to a corrosion in case of non zinccoated lines. Since the corrosion speed strongly increases from a relative humidity of 50 % this value should not be exceeded in any case. Most of the compressed air lines are made from steel or non zinc-coated steel. For each process the observance of a certain moisture content is the condition for a durably failure-free functioning of the whole system. In case of big compressors this value will be much higher.ĭepending on the application different demands are made on the compressed air. For example, a 30 kW compressor thus releases approximately 20 litres into the compressed air line at a humidity level of 60 % and an ambient temperature of 20 ☌ in eight hours. The amount of liquid which drops out under pressure can be large. This means that the relative humidity on the output of a compressor will always be at 100 % and that there will be additional water drops in the outgoing air. By means of an additional decrease of the temperature even more water will condensate. The air is saturated and part of the water drops out as condensate. At a certain point of the compression process the water content of the air exceeds the decreasing ability of the air to bind water. A compressor compresses atmospheric ambient air into a fraction of its original volume. Conversely, if the air is compressed, the capacity to bind water vapour is reduced. However, moisture must be reduced by means of dryers (refrigeration dryers, membrane dryers, adsorption dryers and so on) which ideally work in a controlled manner independent of any load.Īir is able to bind more water vapour the higher the temperature and the larger the volume. Residual oil and dust particles can be removed by means of complex filter systems. The aim is to produce dry and oil-free compressed air which is low in dust particles with the smallest possible effort. Usually, compressed air is generated from ambient air which must be aspirated, compressed by using pistons or screw compressors and which must then be dried more or less strongly. ![]()
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