| 主权项 |
1. A device for cool drying a gas comprising:
a cooling circuit including a heat exchanger having a vaporizer, a compressor for compressing a cooling fluid, wherein said compressor is driven by a motor, a condenser arranged to condense said cooling fluid, an expansion device between an outlet of the condenser and an inlet of the vaporizer, a control device arranged to control the motor of the compressor, and a measuring device coupled thereto; said heat exchanger having an inlet and outlet pipe arranged to receive the gas to be dried; a liquid separator connected to the outlet pipe of the heat exchanger, wherein the measuring device includes a first temperature measuring device arranged to measure the lowest air temperature of the gas to be dried, a second temperature measuring device arranged to measure the ambient temperature and a flow meter in the pipe for the gas to be dried, wherein said control device is configured so that the control device is switchable in at least two user modes for controlling the lowest air temperature of the gas to be dried, said at least two user modes including; a first user mode in which the cooling circuit is only activated when the measured flow of the gas to be dried through the pipe exceeds a preset value and where the cooling circuit is switched off each time the lowest air temperature drops to a preset minimum value, and remains switched off until the lowest air temperature has reached a certain top value, and a second user mode in which the cooling circuit is controlled by switching the motor on and off, so as to maintain the lowest air temperature of the gas to be dried between a preset minimum and maximum threshold value, and wherein the control device is provided with algorithms using a function of the measured ambient temperature for calculating the threshold values, wherein said minimum threshold value is determined according to a step function configured so that said minimum threshold value is constant for ambient temperatures lower than a first set value and constant for ambient temperatures higher than a second set value, and wherein the minimum threshold value increases as the ambient temperatures increase for ambient temperatures between the first and second set value, and wherein said maximum threshold value is determined according to a step function configured so that the maximum threshold value is constant for ambient temperatures lower than a third set value and maximum threshold value increases as the ambient temperature increases for ambient temperatures between the third set value and a fourth set value, said fourth set value being higher than the third set value. |
