Piston Type Axial Expander

Abstract

The invention relates to a piston type axial expander ( 4 ) comprising: an intake cylinder head ( 10 ) for vapor under pressure comprising a vapor intake opening ( 100 ), an expansion zone comprising a plurality of cylinders ( 110 ), wherein a piston ( 111 ) sliding in each respective cylinder is connected to a shaft ( 40 ) by an inclined plate ( 20 ), each piston being parallel to said shaft. a plurality of poppet valves ( 12 ) arranged orthogonally to the shaft ( 40 ) in the intake cylinder head ( 10 ) allowing alternating intake of vapor into said cylinders ( 110 ), each valve ( 12 ) being controlled by a cam ( 21 ) arranged on the shaft ( 40 ), a lift mechanism ( 13 ) for each valve cooperating with the cam, a return mechanism for each valve. The intake cylinder head ( 10 ) comprises: an enclosed and lubricated central zone ( 10 A) comprising the cam and the lift and return mechanisms of the valves, a peripheral zone ( 10 B) in which the intake opening ( 100 ) leads, extending around the central zone ( 10 A).

1 . A piston type axial expander comprising:
 an intake cylinder head for vapor under pressure comprising a vapor intake opening),   an expansion zone comprising a plurality of cylinders, wherein a piston sliding in each respective cylinder is connected to a shaft by an inclined plate, each piston being parallel to said shaft,   a plurality of poppet valves arranged orthogonally to the shaft in the intake cylinder head allowing alternating intake of vapor into said cylinders, each valve being controlled by a cam arranged on the shaft,   a lift mechanism for each valve cooperating with the cam,   a return mechanism for each valve,   
       wherein the intake cylinder head further comprises:
 an enclosed and lubricated central zone comprising the cam and the lift and return mechanisms of the valves, 
 a peripheral zone in which the intake opening leads, extending around the central zone. 
 
     
     
         2 . The expander according to  claim 1 , wherein said peripheral zone extends only around an upper portion of the central zone. 
     
     
         3 . The expander according to  claim 2 , wherein said peripheral zone does not comprise a common wall with the lower portion of the central zone. 
     
     
         4 . The expander according to  claim 1 , further comprising a lubrication circuit for the central zone, said circuit comprising:
 a channel arranged in the shaft and leading into the central zone through a lubricant entry opening, and   a lubricant output opening arranged in a wall of the lower portion of the central zone.   
     
     
         5 . The expander according to  claim 1 , wherein the central zone comprises, in an upper portion thereof, a through opening for the vapor in fluid connection with an exhaust zone of the expander. 
     
     
         6 . The expander according to  claim 1 , wherein the return mechanism of each valve comprises a torsion bar and a return rocker arm extending between said torsion bar and the stem of a respective valve so as to exert a force pressing the head of the valve into the seat of said valve. 
     
     
         7 . The expander according to  claim 6 , wherein the torsion bar is parallel to the shaft. 
     
     
         8 . The expander according to  claim 6 , wherein said return rocker arm is secured to the valve stem by a fork. 
     
     
         9 . The expander according to  claim 8 , wherein the fork is in contact with the valve tip at two contact points of which the axis is not parallel to the axis of rotation of the return rocker arm, so that the fork induces a rotation of the stem about the axis of said stem. 
     
     
         10 . The expander according to  claim 1 , wherein the lift mechanism of each valve comprises a pivoting cam follower rocker arm secured to a respective valve, said cam follower rocker arm cooperating with the cam so as to separate the head of said valve from the seat of said valve. 
     
     
         11 . The expander according to  claim 1 , wherein the pistons are double-acting.