Unit For Generating and Treating Compressed Aeriform Fluids, With an Improved Cooling System

Abstract

The unit ( 1 ) comprises a positive-displacement compressor ( 2 ) including: a prime mover ( 4 ), a rotatable shaft ( 5 ) rotatable by the prime mover ( 4 ), and at least one cylinder ( 7 - 10 ) in which an associated piston ( 11, 12 ), coupled to the shaft ( 5 ) by means of a crank mechanism ( 13, 14 ), is mounted for sliding in a leaktight manner; and a heat-exchanger unit ( 3 ) for receiving and cooling the compressed fluid produced by the compressor ( 2 ). The unit comprises at least one tapping duct ( 41; 41 a, 41 b ) extending between the heat-exchanger unit ( 3 ) and that region of the at least one cylinder ( 7 - 10 ) which is disposed between the associated piston and the shaft ( 5 ), the duct being suitable for supplying a flow of compressed fluid to that region in operation in a manner such that the flow of fluid can expand and be cooled further in that region.

1 . A unit ( 1 ) for generating and treating a compressed aeriform fluid, in particular air, comprising
 a positive-displacement compressor ( 2 ) including   a prime mover ( 4 ),   a rotatable shaft ( 5 ) rotatable by the prime mover ( 4 ), and   at least one cylinder ( 7 - 10 ) in which an associated piston ( 11 ,  12 ), coupled to the shaft ( 5 ) by means of a crank mechanism ( 13 ,  14 ), is mounted for sliding in a leaktight manner; and   a heat-exchanger unit ( 3 ) for receiving and cooling the compressed fluid produced by the compressor ( 2 ),   the generating and treatment unit being characterized in that it comprises at least one tapping duct ( 41 ;  41   a ,  41   b ) extending between the heat-exchanger unit ( 3 ) and that region of the at least one cylinder ( 7 - 10 ) which is disposed between the associated piston and the shaft ( 5 ), the duct being suitable for supplying a flow of compressed fluid to that region in operation in a manner such that the flow of fluid can expand and be cooled further in that region.   
   
   
       2 . A unit according to  claim 1  which is associated with a dryer connected to the output of the heat-exchanger ( 3 ) and in which the at least one tapping duct ( 41 ) extends from a point downstream of the output of the dryer. 
   
   
       3 . A unit according to  claim 1  in which an electrically-controlled, motor-driven fan ( 37 - 40 ) is associated with the at least one cylinder ( 7 - 10 ). 
   
   
       4 . A unit according to  claim 3  in which control means ( 50 ) are associated with the or each motor-driven fan ( 37 - 40 ) and can bring about the de-activation thereof with a predetermined delay with respect to the de-activation of the prime mover ( 4 ). 
   
   
       5 . A unit according to  claim 3  in which control means ( 50 ) are associated with the or each motor-driven fan ( 37 - 40 ) and are arranged to bring about the activation thereof with a predetermined advance with respect to the activation of the prime mover ( 4 ). 
   
   
       6 . A unit according to any one of  claim 3  in which the extent of the advance and/or delay is predetermined in dependence on a temperature detected in the unit. 
   
   
       7 . A unit according to  claim 6  in which the temperature is detected in the head of the at least one cylinder. 
   
   
       8 . A unit according to  claim 6  in which the temperature is detected in the crank mechanism ( 13 ,  14 ). 
   
   
       9 . A unit according to any one of  claim 3  in which the at least one motor-driven fan ( 37 - 40 ) and/or associated control means can bring about a reversal of the direction of rotation of the at least one motor-driven fan ( 37 - 40 ), and hence a reversal of the ventilation air-flow, according to the outside temperature. 
   
   
       10 . A unit according to  claim 1 , comprising a single cylinder in which an associated piston is mounted for sliding and with which at least one motor-driven fan is associated. 
   
   
       11 . A unit according to  claim 1  comprising a plurality of cylinders ( 7 - 10 ) in which respective pistons ( 11 ,  12 ) are mounted for sliding in a leaktight manner, at least one respective motor-driven fan ( 37 - 40 ) being associated with each cylinder ( 7 - 10 ). 
   
   
       12 . A unit according to  claim 11  in which a respective plurality of motor-driven fans is associated with each cylinder ( 7 - 10 ). 
   
   
       13 . A unit according to  claim 1  comprising a plurality of cylinders ( 7 - 10 ) in which respective pistons ( 11 ,  12 ) are mounted for sliding in a leaktight manner, a motor-driven fan being associated with two or more of the cylinders. 
   
   
       14 . A unit according to  claim 11  in which the or each motor-driven fan is driven at a speed of rotation such that the formation of ice on the heat-exchanger ( 3 ) is prevented. 
   
   
       15 . A unit according to  claim 11  with which at least one membrane dryer is associated, and in which the or each motor-driven fan is driven at a speed of rotation which varies in accordance with a predetermined function of the external temperature. 
   
   
       16 . A unit according to  claim 1  in which the or each motor-driven fan ( 37 - 40 ) is driven at a speed an in a direction of rotation which are determined in accordance with predetermined procedures according to the temperature of the aeriform fluid at the output of the heat-exchanger unit ( 3 ). 
   
   
       17 . A unit for generating and treating a compressed aeriform fluid, in particular air, substantially as described and illustrated and for the purposes specified.