Centrifugal Oil Pump Equipment for Vacuum Pump

Abstract

A centrifugal oil pump apparatus, preferably for a vacuum pump, comprises: an oil reservoir having at least one opening and extending radially around a vacuum pump drive shaft; an oil pump inlet arranged below the at least one opening, wherein an oil level in the oil reservoir is arranged above the oil pump impeller, and wherein oil is supplied downwardly to the oil pump inlet; an oil pump drive shaft coupled to the vacuum pump drive shaft; an oil pump impeller coupled to the oil pump drive shaft, the oil pump impeller exerting a centrifugal force on the oil towards a volute such that the oil exits the volute under pressure; and a non-rotating shield member surrounding the oil pump drive shaft, the shield member preventing the oil from rotating with rotation of the oil pump drive shaft.

Description

[Technical field]

[0001] The present invention relates to a centrifugal oil pump arrangement for a vacuum pump. [Background technology]

[0002] The bearings and gears of a dry-running vacuum pump are lubricated with oil to ensure a long life and reliable operation. In a vertical dry-running vacuum pump, the upper and lower bearings are difficult to lubricate with oil if they are not completely submerged in oil. In addition, both the upper and lower gearboxes of the vacuum pump are at low pressure during continuous operation. Both the vertical design and the low pressure during continuous operation of the vacuum pump place special and challenging requirements on the design and implementation of a reliable oil lubrication system for a vertical dry-running vacuum pump. In particular, it is necessary to ensure that individual components such as the gears and the upper and lower bearings are effectively lubricated with oil while at the same time preventing the oil from leaking to other parts of the vacuum pump system.

[0003] Therefore, a need exists for a reliable and efficient oil lubrication solution for dry running vacuum pumps that ensures reliable and efficient lubrication of the individual vacuum pump components.

[0004] Known solutions for lubricating vacuum pump bearings include the use of greases.

[0005] One drawback of known solutions for lubrication of vacuum pump bearings and other components such as vacuum pump gears is the need to frequently monitor the condition of the lubricated components, since there is a high risk of damage and / or failure of the vacuum system due to under- or over-greasing, the use of hardened or old grease, and possible contamination of the grease.

[0006] Another drawback is the high maintenance costs. Summary of the Invention [Problem to be solved by the invention]

[0007] It is an object of the present invention to provide a reliable and effective oil lubrication solution for vacuum pumps which reduces the risk of vacuum pump failure due to insufficient lubrication of the vacuum pump's bearings and / or gears. [Means for solving the problem]

[0008] This object is achieved by a centrifugal oil pump arrangement according to claim 1 and by a vacuum pump comprising a centrifugal oil pump arrangement according to claim 11.

[0009] According to a first aspect of the present invention, a centrifugal oil pump device for a vacuum pump comprises an oil reservoir having at least one opening and extending radially around a vacuum pump drive shaft; an oil pump inlet arranged below the at least one opening, the oil reservoir being arranged above an oil pump impeller such that oil is supplied downwards towards the oil pump impeller via the at least one opening and the oil pump inlet; an oil pump drive shaft coupled to the vacuum pump drive shaft; an oil pump impeller coupled to the oil pump drive shaft, the oil pump impeller centrifugal force the oil towards a volute such that the oil leaves the volute under pressure; and a non-rotating shield member surrounding the oil pump drive shaft, the shield member preventing the oil from rotating due to the rotation of the oil pump drive shaft. In this way, oil from the oil reservoir is supplied to the oil pump inlet without being subjected to centrifugal force by the rotating oil pump drive shaft. The oil is then pressurized in the centrifugal oil pump and sent to the respective vacuum pump components for lubrication.

[0010] Preferably, the shield member comprises a shield element extending axially along the axis of rotation of the oil pump drive shaft, in other words forming a collar or sleeve around the outer circumferential surface along the axis of rotation of the oil pump drive shaft, which can have the advantage of preventing oil from contacting the surface of the rotating oil pump drive shaft and therefore being subjected to centrifugal forces away from the oil pump inlet, and as a consequence preventing oil starvation.

[0011] Preferably, the shield member comprises at least two or more radial shield vanes. More preferably, the shield member comprises three or more radial shield vanes, and most preferably four or more radial shield vanes. This can have the added advantage that when oil contacts the rotating oil pump drive shaft, the rotating oil is impeded by the radial shield vanes. The rotational flow is prevented and the radial shield vanes act as a flow resistance.

[0012] Preferably, radial shield vanes extend radially from the shield member.

[0013] Preferably, the radial shield vanes are evenly distributed around the circumference of the shield member.

[0014] Preferably, the shield member is coupled to the housing via one or more radial shield vanes.

[0015] Preferably, the at least one opening is radially disposed about the oil pump drive shaft and may be radially adjacent to the shield element, preferably disposed below the radial shield vane. The at least one opening may be an annular opening radially disposed about the oil pump drive shaft.

[0016] Preferably, the oil pump impeller comprises at least two impeller vanes, the impeller vanes preferably having a non-zero radius of curvature, which may have the advantage that oil can pass through the oil pump inlet into the region between the impeller vanes, which can then accelerate the oil, allowing it to enter the volute with increased kinetic energy.

[0017] Preferably, each of the impeller vanes comprises a first end and a second end, each first end being disposed tangentially to the volute, which may have the advantage of reducing loss of kinetic energy of the accelerated oil due to friction at the ends of the impeller vanes.

[0018] Preferably, the volute is connected to the oil pump outlet, the cross-sectional area of ​​the volute increasing with decreasing distance to the oil pump outlet, which can have the advantage that the kinetic energy of the oil is converted into hydrostatic energy as it approaches the oil pump outlet.

[0019] According to a second aspect of the present invention, a centrifugal oil pump arrangement, preferably for a vacuum pump, comprises an oil pump inlet located at the center of an oil pump impeller coupled to a pump oil pump drive shaft, the oil pump drive shaft being coupled to a vacuum pump drive shaft, the oil pump impeller exerting a centrifugal force on the oil towards a volute such that the oil leaves the volute under pressure; and a non-rotating shield member surrounding the oil pump drive shaft. In this way, oil can be fed to the oil pump inlet and then pressurized in the centrifugal oil pump and sent to the respective vacuum pump components for lubrication without being subjected to a remote centrifugal force by the rotating vacuum pump drive shaft.

[0020] Preferably, there is a gap between the shield member and the oil pump drive shaft to allow ventilation of the volute, which has the advantage of preventing foaming of the oil due to gas molecules contained in the oil.

[0021] Preferably, the shield member extends axially along the axis of rotation of the oil pump drive shaft, in other words the shield member forms a collar or sleeve around the outer circumferential surface along the axis of rotation of the oil pump drive shaft, which can have the advantage that the oil pump drive shaft is sealed from contact with oil along its surface.

[0022] According to a third aspect of the present invention, there is provided a vacuum pump comprising a centrifugal oil pump arrangement according to the first aspect of the present invention. The vacuum pump comprises a vacuum pump casing, a vacuum pump motor, at least one pump rotor, a vacuum pump bearing supporting the pump rotor, and a vacuum pump drive shaft. In that respect, the oil pump drive shaft is coupled to the vacuum pump drive shaft. In this way, it is possible to ensure that individual components such as bearings and gears of the vacuum pump are lubricated with oil, which can have the advantage that failures or downtime due to wear can be reduced.

[0023] Preferably, the vacuum pump comprising the centrifugal oil pump arrangement according to the first aspect of the present invention is a vertical Roots pump.

[0024] Preferably, the oil pump drive shaft and the vacuum pump drive shaft are integrally formed, which can have the advantage that manufacturing costs can be reduced.

[0025] Preferably, the vacuum pump comprises at least one vacuum pump gear, at least one vacuum pump upper bearing and at least one vacuum pump lower bearing, and the centrifugal oil pump device supplies oil for lubricating the at least one vacuum pump gear and / or the at least one vacuum pump upper bearing and / or the at least one vacuum pump lower bearing. This can have the advantage that these components can be lubricated with oil, which can reduce maintenance costs and ensure continuous and reliable operation of the vacuum pump.

[0026] According to a fourth aspect of the present invention, there is provided a vacuum pump comprising a centrifugal oil pump arrangement according to the second aspect of the present invention. The vacuum pump comprises a vacuum pump casing, a vacuum pump motor, at least one pump rotor, a vacuum pump bearing supporting the pump rotor, and a vacuum pump drive shaft. In that respect, the oil pump drive shaft is coupled to the vacuum pump drive shaft. In this way, it is possible to ensure that the individual components of the vacuum pump, such as the bearings and gears, are lubricated with oil, which results in reduced failures or downtime due to wear.

[0027] Preferably, the vacuum pump comprises an oil reservoir extending radially around the oil pump drive shaft, the oil reservoir comprising at least one opening, the at least one opening of the oil reservoir being connected to the oil pump inlet by a connecting member, this can have the advantage that the at least one opening of the oil reservoir can be positioned remotely relative to the rotating oil pump drive shaft and oil can be supplied from the oil reservoir to the oil pump inlet.

[0028] Preferably, the oil pump drive shaft and the vacuum pump drive shaft are integrally formed, which can have the advantages of reducing manufacturing costs, improving the reliability of the system due to the reduced number of components, and reducing the respective risks of failure on the joints between the components.

[0029] Preferably, the vacuum pump comprises at least one vacuum pump gear, at least one vacuum pump upper bearing and at least one vacuum pump lower bearing, and the centrifugal oil pump device supplies oil for lubricating the at least one vacuum pump gear and / or the at least one vacuum pump upper bearing and / or the at least one vacuum pump lower bearing. This can have the advantage that these components can be lubricated with oil, which can reduce maintenance costs and ensure continuous and reliable operation of the vacuum pump.

[0030] The present invention will now be described in more detail by way of preferred embodiments with reference to the accompanying drawings. [Brief description of the drawings]

[0031] [Figure 1A] 1 shows a centrifugal oil pump arrangement, preferably for a vacuum pump, according to an embodiment of the first aspect of the present invention; [Figure 1B] 1B shows a top view of a centrifugal oil pump arrangement preferably for the vacuum pump shown in FIG. 1A. [Figure 1C] FIG. 2 shows a detailed view of the impeller and volute of the oil pump arrangement according to an embodiment of the first aspect of the present invention. [Figure 2A] 2 shows a centrifugal oil pump arrangement, preferably for a vacuum pump, according to an embodiment of the second aspect of the present invention; [Figure 2B] FIG. 4 shows a detailed view of the impeller and volute of the oil pump arrangement according to an embodiment of the second aspect of the present invention. [Diagram 3] 1 shows a vacuum pump equipped with a centrifugal oil pump device according to a first or second aspect of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] The centrifugal oil pump arrangement 100 as shown in FIG. 1A comprises an oil reservoir 10 extending radially around an oil pump drive shaft 50. The oil reservoir 10 comprises an annular opening 11 for supplying oil from the oil reservoir 10 to an oil pump inlet 30 located below the annular opening 11. However, the opening 11 may have a shape other than annular as shown in FIG. 1A. Furthermore, the number of openings 11 may be two or more. As can be seen from FIG. 1A, the oil reservoir 10 is above the oil pump inlet 30. Thus, in the embodiment shown in FIG. 1A, oil under gravity is supplied from the reservoir 10 through the opening 11 below the oil pump inlet 30.

[0033] As shown in Figure 1A, an oil pump drive shaft 50 is coupled to the vacuum pump drive shaft 20. In addition, an oil pump impeller 40 is coupled to the oil pump drive shaft 50. During operation of the vacuum pump, the oil pump drive shaft 50 is driven by the rotating vacuum pump drive shaft 20, and the oil pump impeller 40 centrifugally forces oil towards the volute 60, causing the oil to exit the volute 60 under pressure towards the oil pump outlet 80 (not shown in Figure 1A).

[0034] Furthermore, the centrifugal oil pump arrangement 100 as shown in Fig. 1A comprises a shield member 70 surrounding the oil pump drive shaft 50. The shield member is fixed and does not rotate with the oil pump drive shaft 50 during operation of the vacuum pump. In the embodiment shown in Fig. 1A, the shield member 70 comprises a shield element 71 extending axially along the rotation axis R of the oil pump drive shaft 50. In this way, the shield element 71 acts as a seal for the oil pump drive shaft 50 and prevents oil from contacting the oil pump drive shaft 50 and, as a result, from rotating with the rotation of the oil pump drive shaft 50 during operation of the vacuum pump.

[0035] As shown in FIG. 1B, the shield member further comprises three radial shield vanes 72. However, the number of radial shield vanes 72 may be different in another embodiment and may be any number of two or more. The three radial shield vanes 72 provide an additional safety measure for the oil pump device. In the unlikely event that the oil contacts the rotating oil pump drive shaft 50 and rotational energy is transferred to the oil, the oil may rotate away from the center of the oil pump inlet, causing the oil surface to become uneven and hindering the flow of oil to the oil pump inlet. Therefore, to prevent the above-mentioned effects of the oil rotation, the radial shield vanes 72 block the oil, which transfers its rotational and / or kinetic energy to the shield vanes 72. Furthermore, the radial shield vanes 72 provide mechanical support to the shield element 71, and as a result, hold the shield element 71 in its respective position.

[0036] FIG. 1C shows a detailed view of the impeller 40 and the volute 60 of the centrifugal oil pump device of the embodiment shown in FIG. 1A. The oil pump impeller 40 shown in FIG. 1C includes four impeller vanes 41 having a non-zero radius of curvature. However, the number of impeller vanes 41 may be different in other embodiments, may be any number greater than or equal to two, and / or may not have a non-zero radius of curvature. Furthermore, each of the impeller vanes 41 includes a first end 411 and a second end 412, with the respective first end 411 being tangentially disposed at the volute 60 and the respective second end 412 facing toward the oil pump drive shaft 50 but not coupled thereto. Oil is supplied from the oil pump inlet 30 (see FIG. 1A) to the divided spaces between the oil pump impeller 40 and the four impeller vanes 41. As the oil pump impeller 40 rotates, oil is accelerated by the impeller vanes 41 and expelled into the curved volute 60 with high kinetic energy.

[0037] 1C, the cross-sectional area of ​​the volute 60 increases as the distance to the oil pump outlet 80 decreases. In this manner, the kinetic energy of the oil decreases as the distance to the oil pump outlet 80 decreases, but the pressure of the oil increases as the distance to the oil pump outlet 80 decreases, allowing the oil to exit the centrifugal oil pump arrangement 100 at high pressure.

[0038] As shown in FIG. 2A, the centrifugal oil pump device 200 includes a vacuum pump drive shaft 120 coupled to an oil pump drive shaft 150. Further, the centrifugal oil pump device 200 includes an oil pump impeller 140 coupled to the oil pump drive shaft 150, and an oil pump inlet 130 is disposed at the center of the oil pump impeller 140. As can be seen from FIG. 2A, oil is supplied upward from an oil reservoir to the oil pump inlet 130 through a connecting member 190 such as a flow passage. The connecting member 190 is disposed offset from the vacuum pump drive shaft 120 and is therefore not affected by the rotation of the vacuum pump drive shaft 120. Therefore, oil can be supplied from the oil reservoir to the centrifugal oil pump device 200 without interruption. In operation, as the oil pump drive shaft 150 is rotated by the rotating vacuum pump drive shaft 120, oil is fed through the oil pump inlet 130 into the impeller passages 141, e.g., drilled holes between the impeller vanes 142, as shown in FIG. 2B and described in detail below, where it is accelerated by the impeller vanes 142 towards the volute 160. The oil then proceeds through the curved volute 160 towards the oil pump outlet 180. Due to the increasing cross-sectional area of ​​the volute 160, the kinetic energy of the oil decreases as the distance to the oil pump outlet 180 decreases, but the pressure of the oil increases.

[0039] As shown in FIG. 2A, the centrifugal oil pump device further includes a shield member 170 extending radially and longitudinally around the oil pump drive shaft 150, which shields the oil pump drive shaft 150 so that the oil is not subjected to the centrifugal force acting on the oil by the rotating oil pump drive shaft 150 during operation. Furthermore, there is a gap 171 between the shield member 170 and the oil pump drive shaft 150 for ventilating the volute 160. Therefore, when the accelerated oil foams due to the gas particles contained therein, the gap 171 can reduce the foaming of the oil and prevent the malfunction of the centrifugal oil pump device 200 caused by the foaming.

[0040] FIG. 2B shows a detailed view of the impeller 140 and the volute 160 of the embodiment shown in FIG. 2A. The oil pump impeller 140 shown in FIG. 2B comprises four impeller channels 141. However, the number of impeller channels 141 may be different in another embodiment and may be any number equal to or greater than two. Furthermore, each of the impeller channels 141 comprises a first end 1411 and a second end 1412, with the respective first end 1411 being disposed toward the volute 160 and the respective second end 14112 facing toward the oil pump inlet 130. Oil is supplied from the oil pump inlet 130 to the impeller channels 141 or the impeller bore. When the oil pump impeller 140 rotates, the oil is subjected to a centrifugal force by the impeller 140 toward the volute 160 and discharged into the volute 160 with high kinetic energy.

[0041] As shown in FIG. 2B, the cross-sectional area of ​​the volute 160 increases as the distance to the oil pump outlet 180 decreases, and therefore the kinetic energy of the oil decreases as the distance to the oil pump outlet 180 decreases, and as a result, the pressure of the oil increases as the distance to the oil pump outlet 180 decreases, and the oil is discharged from the centrifugal oil pump arrangement 200 (see FIG. 2A) under high pressure to lubricate, for example, gears and / or bearings of the vacuum pump.

[0042] FIG. 3 shows a vacuum pump 300 with a centrifugal oil pump arrangement 400 according to the embodiment shown in FIG. 1A, FIG. 1B, FIG. 1C or FIG. 2A, FIG. 2B. In the embodiment shown in FIG. 3, the vacuum pump 300 comprises a motor 500 driving the vacuum pump drive shaft 20, 120. Furthermore, an upper bearing 321 and a lower bearing 322 are arranged at the opposite end of the vacuum pump rotor 340. Furthermore, the vacuum pump 300 can comprise at least one lower gear 332 at the end of the vacuum pump rotor 310 to allow synchronization with a second vacuum pump drive shaft, in particular a screw pump, scroll pump, roots pump, etc. Also, the gear 332 can be arranged either at the top or at the bottom. However, the invention is not limited to a specific arrangement of the bearings 321, 322 and / or the at least one gear 332. During operation, the centrifugal oil pump device 400 discharges pressurized oil to the oil pump outlets 80, 180, which are supplied to the upper bearing 321 and the lower bearing 322 via the connecting member 350. Another connecting member 360 returns the oil from the upper bearing 321 to the oil reservoir 310. From the lower bearing 322 and the lower gear 332, the oil is discharged to the oil reservoir 310. In this way, the upper bearing 321, the lower bearing 322, and at least one gear 332 of the vacuum pump can be efficiently and reliably lubricated by the centrifugal oil pump device 400.

[0043] Thus, a centrifugal oil pump arrangement is provided for effectively and reliably lubricating the individual vacuum pump components. [Explanation of symbols]

[0044] 100, 200 Centrifugal oil pump device 10 Oil Reservoir 11 Annular opening 20, 120 Vacuum pump drive shaft 30, 130 Oil pump inlet 40, 140 Oil pump impeller 41 Impeller Vane 411 first end of impeller vane 412 Second end of impeller vane 50, 150 Oil pump drive shaft 60, 160 Volute 70, 170 Shielding material 71 Shielding Elements 72 Radial Shield Vane 80, 180 Oil pump outlet 141 Impeller passage 1411 First end of impeller passage 1412 second end of impeller passage 171 Gap 190 Connection parts 300 Vacuum Pump 321 Vacuum pump upper bearing 322 Vacuum pump lower bearing 332 Vacuum pump gear 340 Vacuum pump rotor 350 Connection parts 360 Connection parts 400 Centrifugal Oil Pump Unit 500 Vacuum pump motor

Claims

1. 1. A centrifugal oil pump apparatus for a vacuum pump, comprising: an oil reservoir having at least one opening and extending radially about the vacuum pump drive shaft; an oil pump inlet disposed below the at least one opening, the oil reservoir being disposed above an oil pump impeller such that oil is supplied downwardly through the at least one opening and the oil pump inlet toward the oil pump impeller; an oil pump drive shaft coupled to the vacuum pump drive shaft; an oil pump impeller coupled to the oil pump drive shaft, the oil pump impeller exerting a centrifugal force on oil toward a volute such that oil exits the volute under pressure; and a non-rotating shield member surrounding the oil pump drive shaft, the shield member preventing oil from rotating due to rotation of the oil pump drive shaft; A centrifugal oil pump device comprising:

2. 2. The centrifugal oil pump apparatus of claim 1, wherein the shield member comprises a shield element extending axially along an axis of rotation of the oil pump drive shaft.

3. The centrifugal oil pump apparatus of claim 2 , wherein the at least one opening is radially disposed about the oil pump drive shaft and radially adjacent the shield element.

4. 4. A centrifugal oil pump arrangement as claimed in claim 2 or 3, wherein the at least one opening is an annular opening radially disposed about the oil pump drive shaft.

5. 5. A centrifugal oil pump arrangement as claimed in claim 1, wherein the shield member comprises at least two radial shield vanes.

6. 6. The centrifugal oil pump apparatus of claim 5, wherein said radial shield vanes extend radially from said shield member.

7. 7. A centrifugal oil pump arrangement as claimed in claim 5 or 6, wherein the at least one opening is located below the radial shield vane.

8. 8. A centrifugal oil pump arrangement as claimed in claim 1, wherein the oil pump impeller comprises at least two impeller vanes.

9. 9. The centrifugal oil pump apparatus of claim 8, wherein said impeller vanes have a non-zero radius of curvature.

10. 10. A centrifugal oil pump arrangement as claimed in any preceding claim, wherein the volute is connected to an oil pump outlet, the cross-sectional area of ​​the volute increasing with decreasing distance to the oil pump outlet.

11. A vacuum pump comprising the centrifugal oil pump device according to any one of claims 1 to 10.

12. 12. The vacuum pump of claim 11, wherein the oil pump drive shaft and the vacuum pump drive shaft are integrally formed.

13. 13. A vacuum pump according to claim 11 or 12, wherein the vacuum pump comprises at least one vacuum pump gear, at least one vacuum pump upper bearing and at least one vacuum pump lower bearing, and the centrifugal oil pump device supplies oil for lubricating the at least one vacuum pump gear and / or the at least one vacuum pump upper bearing and / or the at least one vacuum pump lower bearing.

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