Abstract
A compressor element (1) comprising at least one compression member (2), a housing (3) and a rotatable shaft (4) rotatably connecting the at least one compression member (2) to the housing (3), wherein at least one intermediate element (5) is provided between the rotatable shaft (4) and the housing (3) for facilitating rotation of the rotatable shaft (4), wherein the compressor element (1) further comprises at least one oil injector (6) extending from an inlet port (7) to at least one nozzle (8a, 8b, 8c) via an oil channel (9), wherein the oil channel (9) is shaped to allow a substantially primary flow of oil through the channel (9) for cooling of the at least one intermediate element (5).
Claims
1-15. (canceled)
16. A compressor element (1) comprising at least one compression member (2), a housing (3) and a rotatable shaft (4) rotatably connecting the at least one compression member (2) to the housing (3), wherein at least one intermediate element (5) comprising at least one of a roller bearing and a gear is provided between the rotatable shaft (4) and the housing (3) for facilitating rotation of the rotatable shaft (4), wherein the compressor element (1) further comprises at least one oil injector (6) extending from an inlet port (7) to at least one nozzle (8a, 8b, 8c) via an oil channel (9), wherein the oil channel (9) is shaped with a radius of curvature (20) larger than 5 mm to allow a flow of oil through the channel (9) for cooling of the at least one intermediate element (5) which is aligned with a direction determined by a centre line of the oil channel (9).
17. The compressor element according to claim 16, wherein the flow has a Dean number smaller than 75, preferably smaller than 65, preferably smaller than 60, wherein the Dean number is determined by the formula wherein Re represent a Reynolds number of the flow of oil; wherein D.sub.n represents an inner diameter of the channel (9); and wherein r represents a radius of curvature (20) of the channel (9) or a portion thereof.
18. The compressor element according to claim 16, wherein an oil channel (9) comprises at least two nozzles (8a, 8b).
19. The compressor element according to claim 16, wherein the oil channel (9) is branched (9a, 9b, 9c).
20. The compressor element according to claim 16, wherein the radius of curvature (20) of the oil channel (9) is larger than 10 mm, preferably larger than 20 mm.
21. The compressor element according to claim 16, wherein the at least one oil injector (6) is arranged on the housing (3) at a distance from the at least one intermediate element (5) and wherein the at least one oil nozzle (8a, 8b, 8c) is biased towards the at least one intermediate element (5) and is configured to eject oil from the at least one oil nozzle (8a, 8b, 8c), wherein the ejected oil is adapted to impact an injection location (10), wherein an area of the injection location (10) is smaller than 10 mm.sup.2, preferably smaller than 5 mm.sup.2.
22. The compressor element according to claim 16, wherein an oil seal (11) is arranged between the compression member (2) and the at least one intermediate element (5).
23. The compressor element according to claim 16, wherein the housing (3) comprises a compression chamber (14) and a driving section (15) separated by a separation wall (23); wherein the compression chamber (14) comprises the at least one compression member (2) and the driving section (15) comprises the at least one intermediate element (5) and wherein the rotatable shaft (4) extends through the separation wall (23).
24. The compressor element according to claim 21, wherein the oil seal (11) is arranged in the separation wall (23).
25. A method for manufacturing a compressor element (1) comprising at least one compression member (2), a housing (3) and a rotatable shaft (4) rotatably connecting the at least one compression member (2) to the housing (3), the method comprises providing at least one intermediate element (5) comprising at least one of a roller bearing and a gear between the rotatable shaft (4) and the housing (3) for facilitating rotation of the rotatable shaft (4), the method further comprises providing the compressor element (1) with at least one oil injector (6) extending from an inlet port (7) to at least one nozzle (8a, 8b, 8c) via an oil channel (9), wherein the method further comprises: shaping the oil channel (9) with a radius of curvature (20) larger than 5 mm to allow a flow of oil through the channel (9) for cooling of the at least one intermediate element (5) which is aligned with a direction determined by a centre line of the oil channel (9).
26. The method according to claim 25, wherein the oil channel (9) is shaped to allow the flow with a Dean number smaller than 75, more preferably smaller than 65, most preferably smaller than 60, wherein the Dean number is determined by the formula wherein Re represent a Reynolds number of the flow of oil; wherein D.sub.n represents an inner diameter of the channel (9); and wherein r represents a radius of curvature (20) of the channel (9) or a portion thereof.
Description
[0019] The accompanying drawings are used to illustrate presently preferred non-limiting exemplary embodiments of devices of the present invention. The above and other advantages of the features and objects of the invention will become more apparent and the invention will be better understood from the following detailed description when read in conjunction with the accompanying drawings, in which:
[0020] FIG. 1 is a schematic representation of an exemplary embodiment of a compressor element comprising an oil injector;
[0021] FIG. 2 is a schematic representation of an exemplary embodiment of a compressor element comprising an oil injector and an oil seal;
[0022] FIG. 3A is a schematic cross-sectional view of an exemplary embodiment of an oil injector;
[0023] FIG. 3B is a schematic perspective view of an exemplary embodiment of an oil injector;
[0024] FIG. 4 is a schematic perspective view of an exemplary embodiment of an oil injector arranged in a portion of the compressor element;
[0025] FIG. 5 is a schematic representation of oil ejected from an oil nozzle at an injection location according to an exemplary embodiment;
[0026] FIG. 6 is a schematic perspective view of another exemplary embodiment of an oil injector arranged in a portion of the compressor element;
[0027] FIG. 7 is a schematic cross-sectional view of an exemplary embodiment of an oil injector.
[0028] FIG. 1 illustrates an exemplary embodiment of a compressor element 1. The compressor element 1 is configured for compressing fluids. In the context of the application, fluids may be considered to include gases or combinations of gas and liquid. For example, the compressor element 1 may be configured to compress air from a low pressure to a high pressure with reference to the low pressure. For this reason the compressor element 1 is provided with a compression member 2.
[0029] The compressor element 1 further comprises a housing 3 and a rotatable shaft 4 rotatably connecting the at least one compression member 2 to the housing 3. The housing 3 may at least partially form the housing of the compression chamber 14 of the compression member 2 and/or may form a structural framework supporting auxiliary compressor means, for example a controllable inlet valve (not shown) or a heat exchanger (not shown).
[0030] The compression member 2 may be any one of the following or a combination thereof: rotary compression member, reciprocating compression member, centrifugal compression member or an axial compression member. For example, the compression member 2 may be a rotary-screw compressor element with two meshing helical screws, or alternatively, the compression member 2 may be a reciprocating compressor element. Moreover, a plurality of compression members 2 may be used such that a multi-stage compressor element is formed. The compression member 2 comprises a compressor inlet 12 configured to receive or draw in a fluid at an inlet pressure into a compression chamber 14. A compression housing delimits the compression chamber 14 (shown in FIG. 2) wherein a compression member 2 is arranged. The compression member 2 may, for example, be two meshing helical screws 2a, 2b. Alternatively, for example in the case of a centrifugal compression member, the compression member 2 may be a centrifugal impeller. The compression member 2 further comprises a compressor outlet 13 from which the fluid is ejected at a higher outlet pressure with respect to the inlet pressure. The compression member 2 may be an oil-free compression member. In the context of the application an oil-free compression member is defined as a compression member 2 wherein an intermediate element 5, such as a crank case or gearbox is isolated from the compression chamber 14. The intermediate element 5 is described further below. To achieve an oil-free compression element an oil seal 11 may be provided between the rotatable shaft 4 and a housing 3, see for example FIG. 2. The oil seal 11 is configured to prevent oil from leaking into the compression chamber 14. Moreover, the compression member 2 may be an oil-less compression member, this is defined as a compression member 2 using no oil. It will be clear to the skilled person that other alternative cooling fluids may be used in substantially the same way as oil. For example, water may be used. The preferred embodiment of the compressor element 1 is an air compressor element.
[0031] The rotatable shaft 4 is arranged in the compressor element 1 such that a rotating motion thereof at least drives the compression member 2. In other words, the rotatable shaft 4 rotatably connects the at least one compression member 2 to the housing 3 and rotates around its longitudinal axis. For this reason the rotatable shaft 4 may be rotatably supported by at least one intermediate element 5. The rotatable shaft 4 may be driven using the at least one intermediate element 5 or, alternatively, a driving means 16 (shown in FIG. 2) to rotate, typically at a predetermined speed. In the illustrated embodiment the compression member 2 is directly arranged on the rotatable shaft 4. Alternatively, the rotatable shaft 4 may be arranged at a distance of the compression member 2, for example in the case of a reciprocating compression member. A plurality of rotatable shafts 4a, 4b, as shown in FIGS. 2, 4, 6 and 7, may also be provided. As shown in FIG. 2, the rotatable shafts 4a, 4b may extend from a driving section 15 to the compression chamber 14. A primary function of the driving section 15 is driving the compression members 2a, 2b. Further details relating to the driving section 15 are explained here below.
[0032] The compressor element 1 further comprises at least one intermediate element 5. The intermediate element 5 is provided between the rotatable shaft 4 and the housing 3 for facilitating rotation of the rotatable shaft 4. The intermediate element 5 may be configured to rotatably support the rotatable shaft 4 with respect to the housing 3. The intermediate element 5 may be any one of a bearing or a gear. In the illustrated embodiment a radial bearing, an axial bearing and a gear are shown. The axial bearing is arranged preferably in the case of an oil-free compressor element such that a substantially axial load is supported by the axial bearing.
[0033] The compressor element 1 further comprises at least one oil injector 6. The oil injector 6 is configured for cooling of the at least one intermediate element 5 and/or the rotatable shaft 4. The oil injector 6 comprises an inlet port 7 and an oil channel 9 extending from the inlet port 7 to at least one nozzle 8. The oil injector 6 is arranged on the housing 3, preferably at a distance from the intermediate element 5 and the at least one nozzle 8 is biased to the intermediate element 5 or at least part of the intermediate element 5, for example a contact area of two gears or the area between raceways of a bearing. The oil nozzle 8 is configured to direct a flow of oil to the intermediate element 5. In a preferred embodiment the oil injector 6 is manufactured using additive manufacturing techniques. The oil injector 6 is preferably manufactured using metal. In other words, the oil injector 6 is integrally formed such that the oil injector 6 is free from leakage paths.
[0034] The inlet port 7 is arranged on the housing 3 or at least a portion thereof, and is in fluid connection with an oil cooling system (not shown). The inlet port 7 is configured to receive oil from the oil cooling system via supply channels. The oil cooling system may comprise a fluid circulation means, heat exchanging means and filtering means. The fluid circulation means is configured for supplying oil to the inlet port 7 via the supply channels (not shown). The heat exchanging means is configured to cool the supplied oil to the desired temperature for optimal cooling performance and the filtering means is configured to filter undesirable sediment and particles which may damage the intermediate elements 5 and/or rotatable shaft 4. The inlet port 7 may be attachable to the housing 3 via a bolt connection or clamping means or may be integrally formed with the housing 3 or at least a portion of the housing 3.
[0035] The oil channel 9 is shaped to allow a substantially primary flow of oil through it. The oil channel 9 comprises a proximal end situated on the inlet port 7 and extends to a nozzle 8 situated at a distal end of the oil channel 9. The oil channel 9 may extend in any direction of a three-dimensional space. The oil channel 9 comprises an oil channel wall delimiting a hollow central portion of the oil channel 9. The oil channel 9 may be straight or curved. Furthermore, the oil channel 9 may also comprise a transport section 18 and a nozzle section 19, shown in FIG. 5. The transport section 18 and the nozzle section 19 may be partially straight and/or partially curved or a combination thereof, this is further explained here below.
[0036] In a preferred embodiment the oil channel 9 is branched such that a plurality of oil channels 9a, 9b, 9c are formed. Each of the plurality of oil channels 9a, 9b, 9c may comprise at least one nozzle 8a, 8b, 8c. By having a plurality of oil channels 9a, 9b, 9c a single oil injector 6 may be used to cool a plurality of intermediate elements 5 or a plurality of parts of an intermediate element 5 or a combination thereof. In the illustrated embodiment of FIG. 1 the oil injector 6 is used to cool and lubricate a radial bearing, an axial bearing and a gear.
[0037] FIG. 2 illustrates an exemplary embodiment of a compressor element 1. Similar or identical parts have been indicated with the same reference numerals as in FIG. 1, and the description given above for FIG. 1 also applies for the components of FIG. 2.
[0038] The compressor element 1 illustrated in FIG. 2 comprises at least one compressor section 14 and at least one driving section 15. The at least one compression chamber 14 and the at least one driving section 15 are separated from each other by a separation wall 23. The separation wall 23 may be formed by the housing 3 or at least a portion thereof. The compression chamber 14 comprises the compressor inlet 12 and compressor outlet 13 and the compression member 2. The compression member 2 may comprise multiple compression members 2a, 2b, for example in the illustrated case of a rotary screw compressor element. Each of the compression members 2a, 2b is connected via a respective rotatable shaft 4a, 4b to the housing 3.
[0039] The plurality of rotatable shafts 4a, 4b rotatably connecting two compression members 2a, 2b to the housing 3 are shown to extend from the driving section 15 to the compression chamber 14. The driving section 15 comprises a plurality of intermediate elements 5a-5f. The rotatable shaft 4a is coupled to a driving means 16 arranged outside of the compressor element 1. The rotatable shaft 4a therefore extends through the housing 3. The driving means 16 is configured to drive the rotatable shaft 4a and by extension the compression members 2a, 2b. For this reason, the compressor element 1 may be provided with an intermediate element 5e arranged on the rotatable shaft 4a for transferring the rotational motion of said rotatable shaft 4a, via intermediate 5e to the rotatable shaft 4b using intermediate element 5f, for example a gearbox. A further driving section (not shown), typically embodying timing gears or synchronization gears, may be situated on the other side of the compression chamber 14 opposite to the driving section 15. The rotatable shafts 4a, 4b may extend in the further driving section such that an end of the rotatable shafts 4a, 4b may be provided with intermediate elements 5 between the rotatable shafts 4a, 4b and the housing 3, for example the intermediate elements 5 between the rotatable shafts 4a, 4b may be embodiment as a set of timing gears. In other words, the rotatable shafts 4a, 4b are rotatably connected to the housing 3 at least at both ends thereof. In an exemplary embodiment the further driving section may correspond to a bearing case.
[0040] Each of the intermediate elements 5a-5d is provided directly or indirectly between the rotatable shafts 4a, 4b and the housing 3, respectively, for facilitating the rotation of the rotatable shafts 4a, 4b. In the exemplary embodiment of FIG. 2, a plurality of oil injectors 6a, 6b is arranged in the compressor element 1. Each of the oil injectors 6a, 6b is configured for cooling of at least one intermediate element 5a-5d. The oil injectors 6a, 6b may be arranged at a same side of the driving section 15 or, as shown in FIG. 2, arranged on opposite sides.
[0041] Optionally, an oil seal 11a, 11b may be arranged between the compression member 2a, 2b and the intermediate element 5a, 5c on the rotatable shaft 4a, 4b. As illustrated in FIG. 2 the driving section 15, comprising a plurality of intermediate elements 5a-f, is separated from the compression chamber 14. Oil seals 11a, 11b may be arranged on each of the respective rotatable shafts 4a, 4b such that oil ejected from the plurality of oil injectors 6a, 6b is not allowed to enter the compression chamber 14. In the case that a further driving section (not shown) is arranged on the other side of the compression chamber 14 opposite to the driving section 15, further oil seals may be provided such that oil injected using yet another further oil injector arranged in the further driving section is not allowed to enter the compression chamber 14.
[0042] FIG. 3A illustrates a schematic cross-sectional view of a different exemplary embodiment of an oil injector 6. In the embodiment of FIG. 3A, the oil channel 9 is shown to be branched into a first oil channel 9a and a second oil channel 9b. Each of the first and second oil channel 9a, 9b comprises at least one nozzle 8a, 8b, respectively. Optionally, the first and second oil channel 9a, 9b may share a common oil channel 9 extending from the inlet port 7.
[0043] FIG. 3A illustrates furthermore that an inner diameter of the oil channel 9 is substantially constant for each section thereof. To allow a substantially primary flow of oil the oil channel 9, in particular a bend thereof, comprises a radius of curvature 20, shown in FIG. 3A, at the center line CL of the oil channel 9 which is larger than 5 mm, preferably, larger than 10 mm, more preferably larger than 20 mm. It will be clear that such a radius of curvature 20 applies to the entire length of an oil channel 9. In this way, no acute, obtuse or straight angles are formed by the oil channel 9. The skilled person will appreciate that the oil channel 9 may comprise a plurality of radii of curvature 20, for example when the oil channel 9 comprises a plurality of bends. In this exemplary case, each of the plurality of bends may comprise a radius of curvature 20 which may be different to each other. In this manner, the direction in which an oil channel 9 extends is customizable such that hard to reach areas may yet be cooled using the above oil injector 6 while a substantially primary flow of oil is maintained.
[0044] FIG. 3A further illustrates that each of the oil channels 9a, 9b and/or nozzles 8a, 8b may have a different shape depending on an injection location, see FIG. 5 for further details regarding the injection location. It is preferred that the shape of the oil channels 9a, 9b and/or oil nozzles 8a, 8b is such that the oil flow is a substantially primary flow of oil. In the context of the application, the primary flow is defined as a flow parallel to the main direction of the fluid motion of the flow of oil, i.e. the centre line CL of the oil channel 9. A primary flow may thus be interpreted as a flow which is substantially unidirectional. In other words, the flow of oil is aligned with the direction of the oil channel 9.
[0045] The primary flow is preferably a flow with a Dean number smaller than 75, preferably smaller than 65, preferably smaller than 60. the Dean number is determined by the formula
[00002]
wherein Re represent a Reynolds number of the flow of oil; wherein D.sub.n represents an inner diameter of the oil channel 9; and wherein r represents a radius of curvature 20 of the oil channel 9 or a portion thereof.
[0046] Alternatively, the Dean number is determined by the formula:
[00003]
[0047] Wherein μ represents a dynamic viscosity of the oil; D.sub.n represents an inner diameter of the oil channel 9; and {dot over (m)} represents the mass flow rate.
[0048] Further alternatively, the Dean number is determined by the formula:
[00004]
[0049] wherein ρ represents a density of the oil; μ represents a dynamic viscosity of the oil; r represents a radius of curvature 20 of the oil channel 9 or a portion thereof; P represents the pumping power of a pump supplying the flow of oil; D.sub.n represents an inner diameter of the oil channel 9; and K represents a correction coefficient. The skilled person will appreciate that different oil channels 9 may have different shapes, mass flow rates and sizes while maintaining a primary flow based on the above formula or a combination thereof:
[00005]
[0050] Experiments have shown that the same mass flow rate may be maintained whilst lowering for example the pumping power. In this way, the efficiency of the compressor element 1 is further improved in addition to improved cooling of intermediate elements 5 due to the primary flow of oil.
[0051] FIG. 3B illustrates a perspective view of yet another different exemplary embodiment of an oil injector 6. In the embodiment of FIG. 3B the oil injector 6 is shown to comprise three oil channels 9a, 9b, 9c. Each of the three oil channels 9a, 9b, 9c comprises a proximal end arranged on a single inlet port 7 and extends from the respective proximal end to a distal end. At the distal end a nozzle 8a-h may be arranged. Each of the oil channels 9a, 9b, 9c may comprise a plurality of nozzles 8a-8h, respectively. In an exemplary case nozzle 8a is arranged at a distal end of the oil channel 9a. Optionally, a nozzle, for example nozzle 8b, may be arranged on an intermediate section of the oil channel 9a. Optionally, a plurality of nozzles 8c-d and 8f-h may be arranged at respectively a distal end of the oil channels 9b, 9c. Optionally, a plurality of nozzles 8c-d may be arranged at a distal end of the oil channel 9b and a nozzle 8e may be arranged in an intermediate section of the oil channel 9b. The skilled person will appreciate that a plurality of nozzles (not shown) may also be arranged in the intermediate section. In this way, both a first side and a second side of an intermediate element (not shown) may be cooled. This is further described in FIGS. 5 and 6. A combination of both embodiments is shown in oil channel 9b wherein the distal end thereof is formed by two nozzles 8c, 8d and the side of the oil channel 9b comprises a nozzle 8e. Moreover, it will also be clear that more than three nozzles may be arranged on an oil channel 9a, 9b, 9c, for example five oil nozzles may be arranged on an oil channel 9a, 9b, 9c.
[0052] FIG. 4 illustrates a perspective view of a side of the housing 3 of the compressor element 1. In the embodiment of FIG. 4, two rotatable shafts 4a, 4b extend through the side of for example the compression chamber 14 into a further driving section, e.g. a bearing case. An intermediate element 5a, 5b is provided between the housing 3 and each of the rotatable shafts 4a, 4b. The intermediate elements 5a, 5b are illustrated as plain bearings comprising rolling elements such as balls or cylinder rollers. The embodiment of FIG. 4 illustrates in particular that a single inlet port 7 may be used to cool a plurality of intermediate elements 5a, 5b. In the exemplary embodiment a first oil channel 9a extends from the inlet port 7 to nozzles 8a, 8b. The nozzles 8a-b are biased in a direction of the rotatable shaft 4a. The second oil channel 9b extends from the inlet port 7 to the nozzle 8c which, in the exemplary case, is biased to the rotatable shaft 4b. It is noted that the area wherein the rotatable shaft 4a, 4b protrudes is typically limited due to built constraints and weight optimization of a compressor element 1, therefore the space for the arrangement of an oil injector 6 is limited. As is illustrated in FIG. 4, the oil injector 6 is arranged on the side of the housing 3 at a distance from the at least one intermediate element 5a, 5b. The oil nozzles 8a-c are configured to eject oil in a direction of an intermediate element 5a, 5b. The ejected oil forms, at least initially when ejected from the nozzle 8a-c, a substantially primary stream. In other words, in the exemplary embodiment of FIG. 4, three oil streams are ejected in a direction of two intermediate elements 5a-b.
[0053] FIG. 5 illustrates a schematic cross section of a rotatable shaft 4 wherein an intermediate element 5 is provided between the rotatable shaft 4 and the housing 3. FIG. 5 in particular illustrates that an oil channel 9 comprises at least one nozzle 8 which is configured to eject oil over a span. An oil stream 21 ejected from the nozzle 8 is adapted to impact an injection location 10 (shown in FIG. 4). The span is defined as the distance between the nozzle 8 and the intermediate element 5. The oil stream 21 ejected from the nozzle 8 is represented by the arrows. The oil stream 21 is adapted to impact an injection location 10 on the intermediate element 5. An area of the injection location 10 is preferably smaller than 10 mm.sup.2, more preferably smaller than 5 mm.sup.2. In other words, it is preferred that a compact stream of oil is maintained without the formation of droplets. Moreover, it is preferred that the compact stream of oil is maintained over substantially the entire span. The injection location 10 may for example be the section of a bearing between two raceways of said bearing. In this way the oil stream 21 may be used for simultaneously cooling and lubricating of the intermediate element 5. It will be clear to the skilled person that once the oil stream 21 impacts the injection location 10, the oil stream 21 may be dispersed. It is preferred that the at least one nozzle 8 is arranged in a substantially close vicinity of the injection location 10. The substantially close vicinity may be defined as an area wherein the span is smaller than 20 mm, preferably smaller than 15 mm, more preferably smaller than 10 mm. In this way it is guaranteed that ejected oil stream 21 impacts the intended injection location 10. This improves the efficiency of cooling the intermediate element 5. Because the oil channel 9 extends from the inlet port 7 to the nozzle 8, the length of the oil channel 9 may be substantial. Moreover, it may be required to incorporate a plurality of bends in order to avoid contact with, for example, intermediate elements 5. This increases the cost and complexity of the oil nozzle 8. In an embodiment where such complexity is unwanted or impossible the oil channel 9 and nozzle 8 may be adapted to eject an oil stream 21 over a long span of at least 20 mm, preferably at least 30 mm, more preferably at least 40 mm. In this way the oil nozzle 8 is more compact and less complex. This reduces the fabrication cost of the oil nozzle 8.
[0054] FIG. 5 further illustrates that an oil channel 9 may comprise a transport section 18 and a nozzle section 19. The transport section 18 is defined as the section between the proximal end and the nozzle section 19 of the oil channel 9. The transport section 18 may extend in any direction. It will be clear that the oil channel 9 may be curved over the entire length of the transport section 18.
[0055] The nozzle section 19 is defined as a distal end of an oil channel 9 comprising the oil nozzle 8. The nozzle section 19 has a length of at least 2 mm, more preferably at least 5 mm, most preferably 10 mm. It is preferred that the nozzle section 19 is substantially straight such that oil ejected from the nozzle 8 forms a substantially primary stream.
[0056] FIGS. 6 and 7 illustrate further embodiments of the compressor element 1 each comprising an oil injector 6. In FIG. 6 a gearbox of a compression member 2 is illustrated comprising two rotatable shafts 4a, 4b and two intermediate elements 5a, 5b illustrated as driving and a driven gear. The intermediate elements 5a, 5b are mounted to the rotatable shafts 4a, 4b respectively at a centre distance of each other and cooperate at a gear meshing location. The oil injector 6 is shown to be arranged on the side of the housing 3 and comprises an oil channel 9a which extends in a direction away from the housing 3 and over the driving gear 5a. The oil nozzle 8a is biased in the direction of the rotatable shaft 4a such that an oil stream ejected from the nozzle impacts an injection location 10 situated on the rotatable shaft 4a. The oil injector 6 further comprises a second oil channel 9b which extends in an area between the housing 3 and the intermediate element 5a. In this way a single oil injector 6 may be used to cool a first side of the driving gear and a second side opposite to the first side.
[0057] FIG. 7 illustrates a further embodiment of a compression member 2 comprising a gearbox wherein a single inlet port 7 is used to cool a plurality of intermediate elements 5a-f. FIG. 7 illustrates in particular the limited available space. FIG. 7 illustrates three oil channels 9a, 9b, 9c. Each of the plurality of oil channels 9a, 9b, 9c respectively comprises a plurality of oil nozzles 8a-f. A first oil channel 9a comprises two oil nozzles 8a, 8b at its distal end which are biased to intermediate elements 5h and 5g. Optionally, a third nozzle (not shown) may be arranged on the first oil channel 9a and may be biased to the intersection of the intermediate element 5b and the rotatable shaft 4b. In this way cooling may be provided to the intermediate element 5b. FIG. 7 further illustrates a second oil channel 9b which extend over the cooperating intermediate elements 5b and 5a. A first oil nozzle 8d may be arranged at a distal end of the oil channel 9b and may be biased to the intermediate element 5c for cooling and lubricating thereof. A second oil nozzle 8c may be arranged at a side of the second oil channel 9b and may be biased to a meshing section of the two intermediate elements 5b, 5a. Optionally and/or additionally, a third oil nozzle (not shown) may be arranged at the distal end of the oil channel 9b and may be biased to an intermediate element 5f (not shown). A third oil channel 9c is similar to the first oil channel and differs in that it extends in opposite direction of the first oil channel 9a such that a second rotatable shaft 4a and the intermediate elements 5d and 5e which facilitate the rotation thereof may be cooled and lubricated.
[0058] Based on the figures and the description, the skilled person will be able to understand the operation and advantages of the invention as well as different embodiments thereof. It is however noted that the description and figures are merely intended for understanding the invention, and not for limiting the invention to certain embodiments or examples used therein. Therefore it is emphasized that the scope of the invention will only be defined in the claims.
