Piston compressor

Abstract

A compressor comprising a cylinder ( 1 ) with an axially reciprocating piston ( 5 ) which compresses gas in the cylinder. At least two circumferential rows of flat fan spray nozzles ( 10 ) spray water into the cylinder during compression. Each nozzle is arranged such that the spray is in a plane substantially parallel to the axis ( 4 ) of the cylinder and is directed towards a central region of the cylinder.

1 : A compressor comprising a cylinder having an axis, a piston reciprocally moveable along the cylinder axis to compress gas in the cylinder and at least two circumferential rows of spray nozzles to spray water into the cylinder during compression, wherein the nozzles are flat fan spray nozzles each of which is arranged such that the spray is in a plane substantially parallel to the axis of the cylinder and is directed towards a central region of the cylinder.  
     
     
         2 : A compressor according to  claim 1 , wherein the plane of the nozzles is inclined at less than 10° to the axis of the cylinder.  
     
     
         3 : A compressor according to  claim 1 , where a nozzle plane is inclined at an angle of less than 5° with respect to the axis of the cylinder.  
     
     
         4 : A compressor according to any one of  claim 1  wherein the nozzles are directed substantially at the axis of the cylinder.  
     
     
         5 : A compressor according to  claim 1 , wherein an offset of one half of the nozzle pitch is introduced between nozzles in adjacent rows.  
     
     
         6 : A compressor according to  claim 1 , wherein the angle of divergence of the fan spray of each row of nozzles decreases towards the cylinder head.  
     
     
         7 : A compressor according to  claim 1 , wherein the nozzles are inclined such that the lower extremity of the spray from the row of nozzles furthest from the cylinder head is at a smaller angle with respect to the cylinder wall than for nozzles closer to the cylinder head.  
     
     
         8 : A compressor according to  claim 1 , wherein the nozzles are mounted with their central axis inclined downwardly with respect to the cylinder axis.  
     
     
         9 : A compressor according to  claim 8 , wherein the top part of the cylinder wall in which the nozzles are mounted is tapered inwardly towards the cylinder head, and the piston is provided with a complementary taper.  
     
     
         10 : A compressor according to  claim 1 , wherein the nozzles extend to a distance from the cylinder head of at least 20%, preferably at least 25% and more preferably at least 30% of the piston stroke.  
     
     
         11 : A compressor according to  claim 1 , wherein the piston rings are offset from the top of the piston such that they remain below the lowermost nozzles at top dead centre.  
     
     
         12 : A compressor according to  claim 1 , further comprising a pre-compressor to compress the gas upstream of the cylinder to a pressure of 2 to 5 bar.  
     
     
         13 : A compressor according to claims  claim 1 , wherein the cylinder is capable of withstanding a peak pressure of at least 20 bar, preferably at least 40 bar and most preferably at least 60 bar.  
     
     
         14 : A compressor according to  claim 1  further comprising means to control the profile of flow rate versus time to the rows of nozzles to allow different profiles for different rows of nozzles during the compression stroke.