Method of maintaining hydraulic pump in a renewable energy turbine generator

Abstract

A hydraulic pump comprises ( 1 ) an outward ring ( 24 ), including demountable blocks ( 30 ) comprising piston cylinders ( 32 ), and an inward ring ( 21 ), comprising a ring cam ( 23 ), coupled through a drive shaft ( 8 ) to the blades of a turbine ( 4 ). To enable maintenance, the outward ring is decoupled from a torque limiting device ( 16, 17 ) and rotated relative to the inward ring. Demountable blocks are then removed from the outward ring using a crane ( 61 ) including a line ( 62 ) extending from above the centre of mass of the demountable block and including a resilient portion ( 66 ) so that although the crane supplies the majority of the force required to remove the demountable block, an operator provides some force, enabling the process to be controlled. The method is suitable for maintaining large hydraulic pumps in wind turbine nacelles ( 2 ).

1 . A method of removing a demountable part from a hydraulic pump in a renewable energy turbine generator,
 wherein the hydraulic pump comprises:   an inward ring comprising a cam having a cam surface;   an outward ring comprising one or more demountable parts, at least some of the demountable parts comprising cylinders, with pistons slidably mounted in the cylinders and in engagement with the cam surface;   first and second axially spaced structural members disposed on opposite sides of the cam;   a housing which is removable to reveal internal components for maintenance and repair; and   a drive shaft coupled to the inward ring;   the method characterised by rotating the outward ring about the drive shaft until the demountable part reaches a selected position, and then removing the demountable part.   
     
     
         2 . A method of removing a demountable part from a hydraulic pump in a renewable energy turbine generator according to  claim 1 , wherein the drive shaft remains fixed in position. 
     
     
         3 . A method of removing a demountable part from a hydraulic pump in a renewable energy turbine generator according to  claim 1 , wherein the hydraulic pump is operated to rotate the outward ring relative to the inward ring by supplying pressurised fluid to at least some of the said cylinders to cause the piston cylinders to carry out motoring cycles and thereby drive the outward ring to rotate relative to the inward ring. 
     
     
         4 . A method of removing a demountable part from a hydraulic pump in a renewable energy turbine generator according to  claim 1 , wherein the renewable energy turbine generator comprises one or more torque reaction devices which detachably connect the pump to a support to prevent rotation of the pump during normal operation, and the method comprises detaching the one or more torque reaction devices to enable the pump to be rotated relative to the support. 
     
     
         5 . A method of removing a demountable part from a hydraulic pump in a renewable energy turbine generator according to  claim 4 , wherein the pump is detachable from the one or more torque reaction devices by sliding the pump or the one or more torque reaction devices. 
     
     
         6 . A method of removing a demountable part from hydraulic pump in a renewable energy turbine generator according to  claim 4 , wherein the one or more torque reaction devices comprise at least one electrical cable through which electrical signals are provided to or received from the hydraulic pump, by way of a said electrical connector or at least one hydraulic line through which hydraulic fluid is supplied to or received from the hydraulic pump by way of the said hydraulic connectors and the method comprises detaching a said electrical cable from a said electrical connector or decoupling a said hydraulic line from a said hydraulic connector. 
     
     
         7 . A method of removing a demountable part from a hydraulic pump in a renewable energy turbine generator according to  claim 1 , wherein the demountable parts are demountable blocks and the outward ring comprise a plurality of said demountable blocks arranged around the axis of the outward ring. 
     
     
         8 . A method of removing a demountable part from a hydraulic pump in a renewable energy turbine generator according to  claim 1 , wherein the hydraulic pump comprises electrical connecters for coupling electrical devices within the hydraulic pump to external electrical connections and the method comprises decoupling the electrical connecters before the outward ring is rotated, and wherein the hydraulic pump comprises hydraulic connecters for coupling hydraulic lines within the hydraulic pump to external hydraulic lines, and the method comprises decoupling the hydraulic connecters before the outward ring is rotated. 
     
     
         9 . A method of removing a demountable part from a hydraulic pump in a renewable energy turbine generator according to  claim 1 , wherein hydraulic fluid is drained from the hydraulic pump before the outward ring is rotated relative to the inward ring. 
     
     
         10 . A method of removing a demountable part from a hydraulic pump in a renewable energy turbine generator according to  claim 1 , wherein the demountable part is removed using a lifting device which exerts a lifting force on the demountable part through a resilient member. 
     
     
         11 . A method of removing a demountable part from a hydraulic pump in a renewable energy turbine generator according to  claim 10 , wherein the demountable part is removed using a lifting device comprising a tensile stress bearing member and a demountable part retaining portion supported by the tensile stress bearing member, the tensile stress bearing member extending vertically from directly above the centre of mass of the demountable part retaining portion and a selected demountable part attached to the demountable part retaining portion. 
     
     
         12 . A method of removing and replacing a demountable part from a hydraulic pump in a renewable energy turbine generator according to  claim 1 , further comprising the step of fitting a demountable part using a lifting device which exerts a lifting force on the demountable part through a resilient member. 
     
     
         13 . A method of removing a demountable part from a hydraulic pump in a renewable energy turbine generator according to  claim 1 , wherein the demountable part is removed using a lifting device which exerts a lifting force which is the majority of the lifting force required to remove the demountable part and wherein a human operative provides the balance of the force required to remove the demountable part. 
     
     
         14 . A method of removing a demountable part from a hydraulic pump in a renewal energy turbine generator according to  claim 1 , wherein the demountable part is removed using a handling device comprising a supported arm extending between a demountable part retaining portion at a first end and a counterweight at the opposite second end. 
     
     
         15 . A method of removing a demountable part from a hydraulic pump in a renewable energy turbine generator according to  claim 1 , wherein the outward ring has an axis extending through the drive shaft and the selected position is above the height of the axis. 
     
     
         16 . A method of removing a demountable part from a hydraulic pump according to  claim 1 , wherein, after the removal of one or more demountable parts, the method may comprise rotating the inward ring to reveal parts of the inward ring through the gap left by the removed demountable parts. 
     
     
         17 . A method of removing a demountable part from a hydraulic pump according to  claim 1 , wherein the renewable energy turbine generator is a wind turbine generator which provides energy to the hydraulic pump during normal operation through the drive shaft, driven by a plurality of turbine blades. 
     
     
         18 . A renewable energy turbine generator comprising a hydraulic pump and a turbine,
 the hydraulic pump comprising:   an inward ring comprising a cam having a cam surface;   an outward ring comprising one or more demountable parts, at least some of the demountable parts comprising cylinders, with pistons slidably mounted in the cylinders and in engagement with the cam surface;   first and second axially spaced structural members disposed on opposite sides of the cam;   a housing which is removable to reveal internal components for maintenance and repair; and   a drive shaft coupled to the inward ring;   characterised by means for rotating the outward ring about the drive shaft until the demountable part reaches a selected position, and then removing the demountable part.   
     
     
         19 . A renewable energy turbine generator according to  claim 18 , wherein the renewable energy turbine generator is a wind turbine generator and the drive shaft is coupled to a plurality of turbine blades. 
     
     
         20 . A lifting mechanism for lifting a demountable part from the outward ring of the hydraulic pump of a renewable energy turbine generator according to  claim 18 , to thereby remove the demountable part, the lifting mechanism including an elongate tensile stress bearing member, at least part of the length of which is resilient.