Breathing Air Dryer DPS 1-8 BI and BM
Adsorption dryers of the DPS 1-8 BI and BM series are designed for drying and purification of compressed air for breathing air applications. ..BI stands for „Breathing air Industrial“, thus for Industrial use acc. EN12021, and ..BM stands for „Breathing air Medical“, thus medical breathing air acc. Pharmacopee Europeene, as it is demanded for hospitals.
With both systems apart from the drying process to a pressure dew point of -40°C also the components CO, CO2, hydrocarbons, nitrogen oxides and SO2 are reduced so far, to residual values underneath the limit values acc. EN12021 (with series DPS..BI), respectively Pharmacopee Europeene (with series DPS..BM).
For drying the compressed air, and removal of the main content of CO2 (i.e. “adsorption“), the compressed air flow is led through a vessel filled with desiccant. The desiccant extracts moisture and CO2 from the compressed air and stores it in its structure until the desiccant is saturated. The saturated desiccant then has to be regenerated, i.e. the moisture and CO2 stored in the structure has to be “removed” before the desiccant can be used for drying again. Continuous operation of an adsorption dryer therefore requires two vessels that are operated alternately. One vessel is used for drying the compressed air and removal of CO2 (adsorption) and the other vessel for regenerating the desiccant. For the DPS series the change interval between adsorption and regeneration is 5 minutes at nominal conditions.
For the regeneration a certain quantity of dried compressed air is drawn off at the dryer outlet (approx. 15% of the nominal volume flow rate at nominal conditions). This amount of compressed air is expanded to atmospheric pressure and is led through the vessel to regenerate the desiccant. The dried, decompressed air is extremely moisture-subsaturated and thus extracts the moisture stored in the desiccant and discharges it to the atmosphere via a silencer.