Patent ID: 7757407

Claim:
Gas drying device, comprising a desiccant dryer including a pressure tank with a drying zone and a regeneration zone, and an adsorption and/or absorption medium which is alternately guided through the drying zone and the regeneration zone; a primary circuit which includes the desiccant dryer, said primary circuit enabling the gas to be dried to be passed through the drying zone of the desiccant dryer; a secondary circuit enabling a part of the gas to be dried to be guided through the regeneration zone of the desiccant dryer for the absorption of moisture; and a cooling dryer which is disposed upstream the desiccant dryer in the primary circuit; wherein the cooling dryer comprises a closed cooling circuit upstream the desiccant dryer, the closed cooling circuit having a compressor, a condenser, and an evaporator defining a primary part of a heat exchanger; and a secondary part of the heat exchanger functions to cool the gas to be dried; wherein upstream of the heat exchanger is provided a first temperature measuring point which registers the temperature of the gas to be dried upstream the heat exchanger; wherein downstream of the heat exchanger is provided a second temperature measuring point which measures the temperature of the gas to be dried downstream the heat exchanger; wherein due at least in part to the first and second temperature measuring points, the gas drying device can produce dried gas with an intended maximum dew point in a wider range of ambient temperatures and in an energy-saving manner; wherein the closed cooling circuit further comprises a throttle valve positioned between an inlet of the evaporator and an outlet of the condenser; wherein the closed cooling circuit further comprises a liquid separator and a control unit, wherein a temperature signal is measured downstream of the liquid separator and is used as a control signal; and wherein said gas drying device further comprises a coolant filter/dryer provided downstream of the heat exchanger, a pressure/shut-off switch provided upstream the filter/dryer, and a third temperature measuring point provided near the pressure/shut-off switch and connected to the control unit.