Air compressor unit

Abstract

A volumetric reciprocating compressor comprises an air compressing unit equipped with a plurality of cylinders adapted to receive reciprocating pistons, a motor for driving the compressing unit and having a shaft which rotates about a respective axis of rotation, a cooling unit comprising a fan assembly driven by the rotating shaft to produce an air flow for cooling the compressed air in the unit, the cylinders being located inside an axisymmetric housing casing and being angularly spaced from each other.

What is claimed is: 
     
         1 . A volumetric reciprocating compressor comprising
 an air compressing unit, said unit comprising a plurality of cylinders adapted to receive reciprocating pistons,   a motor for driving the compressing unit and having a shaft which rotates about a respective axis of rotation,   cooling means comprising at least one fan assembly driven by the rotating shaft to produce an air flow for cooling the compressed air in the unit, characterized in that the cylinders are located inside an axisymmetrically shaped housing casing and are angularly spaced from each other, and in that they have respective central axes which lie in respective planes which are parallel to each other and perpendicular to the axis of rotation of the rotating shaft.   
     
     
         2 . The compressor according to  claim 1 , characterized in that it comprises, for each of the pistons, a respective con rod and a crank lever member which is rotatably connected to the con rod at the respective small end and which is eccentrically connected to the rotating shaft. 
     
     
         3 . The compressor according to  claim 2 , characterized in that the crank lever member is connected to the shaft by a shape fit which allows it to rotate as one with the shaft. 
     
     
         4 . The compressor according to  claim 1 , characterized in that the cooling means comprise an element for containing the fan assembly, the containing element having an axisymmetrical configuration and comprising a duct for cooling the compressed air discharged from the air compressing unit. 
     
     
         5 . The compressor according to  claim 4 , characterized in that the cooling duct is at least partly annular in shape and extends along the periphery of the containing element. 
     
     
         6 . The compressor according to  claim 4 , characterized in that the containing element is interposed between the air compressing unit and the drive motor. 
     
     
         7 . The compressor according to  claim 4 , where the containing element for the fan assembly has at least one wall which is transversal to the axis of rotation of the motor, characterized in that the wall has a plurality of openings designed to allow the passage of the air flow produced by the fan assembly. 
     
     
         8 . The compressor according to  claim 7 , characterized in that the containing element for the fan assembly has two walls which are transversal to the axis of rotation of the motor and which are located on opposite sides of the fan assembly, both of the walls having a plurality of openings designed to allow the passage of the air flow produced by the fan assembly. 
     
     
         9 . The compressor according to  claim 1 , characterized in that the casing housing the cylinders has, between the cylinders, a plurality of cooling fins defining multiple channels through which the cooling air flow produced by the fan assembly passes.