Refrigeration air dryer

Abstract

A refrigeration air dryer outputs dehumidified air dehumidified by a cooling operation using a low-temperature refrigerant after the temperature thereof has been raised by exchanging heat with a high-temperature refrigerant at a reheater. The refrigeration air dryer includes a temperature sensor which detects the temperature of secondary air in the outlet pipe, valve means which adjusts the flow rate of the dehumidified air or the flow rate of the refrigerant flowing through the reheater, and a temperature controller which adjusts the flow rate of the dehumidified air or the flow rate of the refrigerant by controlling the valve means based upon the detected temperature detected by the temperature sensor, thereby maintaining the temperature of the secondary air at a constant level.

1 . A refrigeration air dryer including:
 a refrigerant system which includes a refrigerant compressor, a condenser condensing a high-temperature refrigerant compressed by the refrigerant compressor, a decompressing mechanism decompressing, by adiabatic expansion, the refrigerant condensed by the condenser, so as to lower the temperature thereof, and a cooler cooling moist compressed air flowing into through an air inlet in an air system, using the low-temperature refrigerant transmitted from the decompressing mechanism, so as to dehumidify the air, and which is configured such that the refrigerant transmitted from the cooler is returned to the refrigerant compressor: and   the air system which includes the air inlet into which moist compressed air flows as a primary air to be dehumidified, the cooler cooling the primary air flowed into from the air inlet so as to obtain low-temperature dehumidified air, and a reheater exchanging heat between the low-temperature dehumidified air transmitted from the cooler and the high-temperature refrigerant transmitted from the refrigerant compressor included in the refrigerant system, and which outputs the dehumidified air, of which the temperature raised by the heat exchange at the reheater, as secondary air via the outlet pipe,   wherein the air dryer includes a temperature sensor detecting the temperature of the secondary air flowing through the outlet pipe, valve means adjusting the flow rate of the dehumidified air or the refrigerant flowing through the reheater, and a temperature controller adjusting the flow rate of the dehumidified air or the refrigerant by controlling the valve means based upon the detected temperature detected in the temperature sensor, so as to maintain the temperature of the secondary air at a constant level.   
   
   
       2 . A refrigeration air dryer according to  claim 1 , wherein the reheater is connected between the refrigerant compressor and the condenser, and
 wherein the refrigerant transmitted from the refrigerant compressor is transmitted to the condenser via the reheater.   
   
   
       3 . A refrigeration air dryer according to  claim 2 , wherein a high-temperature refrigerant pipe connecting the refrigerant compressor and the reheater and a low-temperature refrigerant pipe connecting the decompressing mechanism and the cooler or a return refrigerant pipe connecting the cooler and the refrigerant compressor are connected via a bypass refrigerant pipe including a volume adjusting valve with an adjustable ratio of valve opening, whereby a portion of the high-temperature refrigerant compressed by the refrigerant compressor is directly flowed through the low-temperature refrigerant pipe or the return refrigerant pipe, in a case in which the load of the cooler becomes small. 
   
   
       4 . A refrigeration air dryer according to any one of  claim 1  through  claim 3 , wherein the valve means comprises a three-way flow adjusting valve having one inlet port and two outlet ports, and
 wherein a portion of the dehumidified air or the refrigerant transmitting to the reheater is flowed by the three-way flow adjusting valve so as to bypass the reheater.   
   
   
       5 . A refrigeration air dryer according to  claim 4 , wherein a bypass pipe bypassing the reheater is connected to the dehumidified air pipe which transmits the dehumidified air from the cooler to the reheater and the outlet pipe which outputs the secondary air transmitted from the reheater, and
 wherein the three-way flow adjusting valve is arranged at a branch point where the bypass pipe and the dehumidified air pipe branch off or at a confluent point of the bypass pipe and the outlet pipe.   
   
   
       6 . A refrigeration air dryer according to  claim 4 , wherein a refrigeration bypass pipe bypassing the reheater is connected to a high-temperature refrigerant pipe connecting the refrigerant compressor and the reheater and an intermediate refrigerant pipe connecting the reheater and the condenser, and
 wherein the three-way flow adjusting valve is arranged at a branch point where the refrigeration bypass pipe and the high-temperature refrigerant pipe branch off or at a confluent point of the refrigerant bypass pipe and the intermediate refrigerant pipe.