Variable Capacity Oil Pump

Abstract

The invention relates to a wind turbine being provided with a fluid displacement means for ensuring a certain increased pumping capacity at a certain reduced rotational speed of the main shaft of the rotor and thus of a drive shaft from a gear box of the wind turbine. The invention also relates to a wind turbine being provided with fluid displacement means for ensuring a certain increased pumping capacity at a certain increased rotational speed of the main shaft of the rotor and thus of a drive shaft from a gear box of the wind turbine. The means may be mechanical, hydraulic, pneumatic or electrical. Additionally, the invention relates to a method for operating a wind turbine being provided with such fluid displacement means.

1 . A wind turbine with a fluid supply system comprising a fluid displacement pump,
 said fluid displacement pump having a drive shaft and a coupling arrangement between at least a first individual pumping member and at least a second individual pumping member, where at least one of said pumping members is individually controllable,   said fluid supply system being capable of exhibiting a certain increased pumping capacity at a certain reduced or increased rotational speed of the drive shaft,   said increased pumping capacity being obtained by controlling a pumping capacity of at least one of said pumping member.   
     
     
         2 . A wind turbine according to  claim 1 , where the fluid supply system comprises
 a fluid inlet and a fluid outlet of the first pumping member and a fluid inlet and a fluid outlet of the second pumping member,   the fluid inlet of the first pumping member leading from a fluid vessel and the fluid outlet of the first pumping member leading only to a main fluid conduit, and   the fluid inlet of the second pumping member leading from a fluid vessel and the fluid outlet of the second pumping member leading both to the main fluid conduit and to a branch fluid conduit of the fluid system,   said branch fluid conduit being provided with a control valve for controlling a flow of fluid to the branch fluid conduit in relation to a flow of fluid to the main fluid conduit.   
     
     
         3 . A wind turbine according to  claim 2 , said branch fluid conduit leading to one of the following fluid elements: the inlet of the first pump, a fluid reservoir and the inlet of the second pump. 
     
     
         4 . A wind turbine according to  claim 1 , where the fluid supply system comprises
 a fluid inlet and a fluid outlet of the first pumping member and a fluid inlet and a fluid outlet of the second pumping member,   the fluid inlet of the first pumping member leading from a fluid outlet of a hydraulic motor, and the fluid outlet of the first pumping member leading to a fluid inlet of the hydraulic motor, and   the fluid inlet of the second pumping member leading from a fluid vessel and the fluid outlet of the second pumping member leading to a main fluid conduit, and   said hydraulic motor being provided with a control valve for controlling a flow of fluid to the hydraulic motor in relation to a flow of fluid to the main fluid conduit.   
     
     
         5 . A wind turbine according to  claim 1 , where the fluid supply system comprises
 a fluid inlet and a fluid outlet of the first pumping member and a fluid inlet and a fluid outlet of the second pumping member,   the fluid inlet of the first pumping member leading from a fluid outlet of an auxiliary hydraulic motor, and the fluid outlet of the first pumping member leading to a fluid inlet of the auxiliary hydraulic motor, and   the fluid inlet of the second pumping member leading from a fluid vessel and the fluid outlet of the second pumping member leading to a main fluid conduit,   said auxiliary hydraulic motor intended for driving at least one of the following speed variable motors: an electrical motor, a pneumatic motor and another hydraulic motor, and said motor being provided with control means for controlling the rotational speed of an output shaft in relation to a flow of fluid to the main fluid conduit.   
     
     
         6 . A wind turbine with a fluid supply system comprising a fluid displacement pump,
 said pump being provided with a coupling arrangement between at least a first pumping member and at least an electric energy generating element providing electrical energy for an electric motor intended for driving the first pumping member,   said at least first pumping member exhibiting a certain reduced or increased pumping capacity at a certain reduced or increased rotational speed of the drive shaft.   
     
     
         7 . A wind turbine according to  claim 1 , where said drive shaft comprises
 a common drive shaft intended for driving at least the first pumping member and at least a second pumping member by a driving means driving the drive shaft, and   said pump further being provided with a mechanical coupling arrangement between the at least first pumping member and the at least second pumping member.   
     
     
         8 . A wind turbine according to  claim 7 , where the mechanical coupling arrangement is provided by means of a single shaft constituting an output shaft of the first pumping member and an input shaft of the second pumping member, said single shaft thereby being common to the two pumping members. 
     
     
         9 . A wind turbine according to  claim 1 , where said drive shaft comprises
 a drive shaft intended for driving at least the second pumping member by a primary driving means driving the drive shaft,   said pump having an output shaft intended for driving at least the first pumping member by a secondary driving means driving the output shaft, said pump further being provided with a hydraulic coupling arrangement between the second pumping member and the driving means driving the output shaft.   
     
     
         10 . A wind turbine according to  claim 9 , wherein
 the hydraulic coupling arrangement is provided by means of a hydraulics outlet constituting an output from the second pumping member, and a hydraulics inlet constituting an input to a hydraulic motor being the secondary driving means and intended for driving the first pumping member, and the hydraulic motor comprising the output shaft intended for driving an input shaft of the at least first pumping member, said output shaft and said input shaft thereby being common to the hydraulic motor and the at least first pumping member.   
     
     
         11 . A wind turbine according to  claim 1 , where said drive shaft comprises a drive shaft intended for driving at least the second pumping member by a primary driving means driving the drive shaft,
 said pump having an output shaft intended for driving at least the first pumping member by a secondary driving means driving the output shaft,   said pump further being provided with a pneumatic coupling arrangement between the at least second pumping member and the driving means driving the output shaft.   
     
     
         12 . A wind turbine according to  claim 11 , where the pneumatic coupling arrangement is provided by means of a pneumatics outlet constituting an output from a second pumping member, and a pneumatics inlet constituting an input to a pneumatic motor being the secondary driving means and intended for driving the first pumping member, and the pneumatic motor comprising the output shaft intended for driving an input shaft of the at least first pumping member, said output shaft and said input shaft thereby being common to the pneumatic motor and the at least first pumping member. 
     
     
         13 . A wind turbine according to  claim 1 , where said drive shaft comprises a drive shaft intended for driving at least the second pumping member by a primary driving means driving the drive shaft, and said pump having an output shaft intended for driving at least the first pumping member by a secondary driving means driving the output shaft, said pump further being provided with a electrical coupling arrangement between the at least second pumping member and the driving means driving the output shaft. 
     
     
         14 . A wind turbine according to  claim 13 , wherein the electrical coupling arrangement is provided by means of an electric outlet constituting an output from the second pumping member, and an electric inlet constituting an input to an electrical motor being the secondary driving means and intended for driving the first pumping member, and the electrical motor comprising the output shaft intended for driving an input shaft of the at least first pumping member, said output shaft and said input shaft thereby being common to the electrical motor and the at least first pumping member. 
     
     
         15 . A wind turbine according to  claim 1 , where the coupling arrangement is a coupling capable of infinitely variably adjusting rotational speed of the second pumping member independently on any change in rotational speed of the drive shaft. 
     
     
         16 . A wind turbine according to  claim 1 , where the coupling arrangement is a coupling capable of stepwise adjusting rotational speed of the second pumping member independently on any change in rotational speed of the drive shaft. 
     
     
         17 . A wind turbine according to  claim 1 , where a driving means of said fluid displacement pump is an electrical driving means such as an electrical motor. 
     
     
         18 . A wind turbine according to  claim 1 , where a driving means of said fluid displacement pump is a mechanical driving means such as a gearbox. 
     
     
         19 . A wind turbine according to  claim 1 , where a driving means of said fluid displacement pump is a hydraulic driving means such as a hydraulic motor. 
     
     
         20 . A wind turbine according to  claim 1 , where a driving means of said fluid displacement pump is a main shaft of a rotor of a wind turbine. 
     
     
         21 . A wind turbine according to  claim 1 , where the at least first pumping member and the at least second pumping member are capable of pumping the fluid independently on a rotational direction of the first and second pumping member. 
     
     
         22 . A wind turbine according to  claim 1 , where said coupling arrangement comprises an epicyclic 3-way differential with one shaft connected to an output drive shaft of the first pumping member, one shaft connected to an input drive shaft of the second pumping member, and the third shaft connected to a speed-variable motor. 
     
     
         23 . A wind turbine according to  claim 22 , where said coupling arrangement is a hydrostatic transmission from the output drive shaft of the first pumping member to the input drive shaft of the second pumping member. 
     
     
         24 . A wind turbine according to any of  claim 22 , where said mechanical coupling arrangement is a hydrodynamic transmission from the output drive shaft of the first pumping member to the input drive shaft of the second pumping member. 
     
     
         25 . A wind turbine according to  claim 1 , where said coupling arrangement is any one of the following coupling arrangements; a mechanical coupling, a viscous coupling, an electric coupling, an electro-mechanical coupling, and where said coupling arrangement is established between an output drive shaft of the first pumping member and an input drive shaft of the second pumping member. 
     
     
         26 . A wind turbine according to  claim 1 , where said coupling arrangement is based on electro-technical principles comprising electromagnetic transmission or Eddie-current. 
     
     
         27 . A wind turbine according to  claim 1 , where at least an inlet of said first pumping member is submerged in fluid of a fluid reservoir for supplying lubrication fluid at least to the first pumping member. 
     
     
         28 . A wind turbine according to  claim 10 , where at least the hydraulics inlet constituting an input to a hydraulic motor being a secondary driving means and intended for driving the first pumping member, is positioned at a horizontal level below a horizontal level of an outlet of a fluid reservoir for supplying pump fluid at least to the hydraulic motor. 
     
     
         29 . A method of controlling a fluid pressure in a fluid supply system of a wind turbine according to  claim 1 , the method comprising:
 monitoring at least one parameter influencing a fluid pressure in the fluid supply system of the wind turbine,   controlling a coupling arrangement between at least a first pumping member and at least a second pumping member   thereby obtaining a certain increased pumping capacity at a certain value of the at least one parameter being monitored.   
     
     
         30 . A method according to  claim 29 , further comprising:
 monitoring rotational speed of a drive shaft of at least one of the first pumping member and the second pumping member,   controlling the coupling arrangement between the at least first pumping member and the at least second pumping member,   thereby obtaining a certain increased pumping capacity at a certain value of the rotational speed of the drive shaft.   
     
     
         31 . A method according to  claim 29 , further comprising
 monitoring an increment of rotational speed of a drive shaft of at least one of the first pumping member and the second pumping member,   controlling the coupling arrangement between the at least first pumping member and the at least second pumping member,   thereby obtaining a certain increased pumping capacity at a certain reduced increment of the rotational speed of the drive shaft.   
     
     
         32 . A method according to  claim 29 , further comprising
 monitoring wind speed at a site of the wind turbine as a parameter influencing rotational speed of a main shaft of the wind turbine,   controlling the coupling arrangement between the at least first pumping member and the at least second pumping member, when the wind speed exhibits a value below 100 m/s during a continuous period of time of at least 10 seconds,   thereby obtaining a certain increased pumping capacity at a certain low value of the wind speed at the site of the wind turbine.   
     
     
         33 . A method according to  claim 29 , further comprising
 monitoring wind speed at a site of the wind turbine as a parameter influencing rotational speed of a main shaft of the wind turbine,   controlling the coupling arrangement between the at least first pumping member and the at least second pumping member, when the wind speed exhibits a value above 1 m/s during a continuous period of time of at least 10 seconds,   thereby obtaining a certain increased pumping capacity at a certain high value of the wind speed at the site of the wind turbine.   
     
     
         34 . A method according to  claim 29 , further comprising
 monitoring rotational speed of a main shaft of the wind turbine influencing rotational speed of the drive shaft from a gearbox of the wind turbine,   controlling the coupling arrangement between the at least first pumping member and the at least second pumping member, when the rotational speed of the main shaft exhibits a value below 100 rpm during a continuous period of time of at least 10 seconds   thereby obtaining a certain increased pumping capacity at a certain low value of the rotational speed of the main shaft.   
     
     
         35 . A method according to  claim 29 , further comprising
 monitoring rotational speed of a main shaft of the wind turbine influencing rotational speed of the drive shaft from a gearbox of the wind turbine,   controlling the coupling arrangement between the at least first pumping member and the at least second pumping member, when the rotational speed of the main shaft exhibits a value above 0.01 rpm during a continuous period of time of at least 10 seconds   thereby obtaining a certain increased pumping capacity at a certain high value of the rotational speed of the main shaft.