Patent ID: 9216378
Filing Date: 2015-12-22
Classification: B01D

Abstract:
1. Method for cool drying gas comprising the steps: guiding a gas through a secondary part of a heat exchanger whose primary part is a vaporizer of a cooling circuit that includes a compressor driven by a motor, a condenser, and an expansion device between an outlet of the condenser and an inlet of the vaporizer; measuring an ambient temperature, at least when no gas to be dried is being supplied, as well as a temperature or a dew point in a vicinity of the place where the temperature of the gas to be dried is the lowest when cool drying; and switching the cooling circuit on and off on the basis of these measurements in order to always maintain the lowest gas temperature or the dew point between a pre-determined minimum and maximum threshold value; wherein one or both of the pre-determined threshold values are calculated on the basis of an algorithm which is a function of the measured ambient temperature; wherein the algorithm of the minimum threshold value as the function of the ambient temperature is formed by a step function with a constant value when the measured ambient temperature is smaller than a first set value; a higher constant value for an ambient temperature that is larger than a second set value which is larger than the first set value; and a rising function between said set values; wherein the algorithm of the maximum threshold value as the function of the ambient temperature is formed by a step function with a constant value when the measured ambient temperature is smaller than a first set value; a higher constant value for an ambient temperature that is larger than a second set value which is larger than the first set value; and a rising function between said set values; and wherein a course of the rising function of the maximum threshold value is steeper than a course of the rising function of the minimum threshold value.