Centrifugal oil pump device for vacuum pumps

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 device for a vacuum pump.

Background Art

[0002] The bearings and gears of a dry-running vacuum pump are lubricated with oil to ensure long-life and reliable operation. In a vertical dry-running vacuum pump, it is difficult to lubricate the upper and lower bearings with oil when they are not completely immersed in oil. Furthermore, both the upper and lower gear boxes 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 pose special and difficult requirements for the design and implementation of a reliable oil lubrication system for vertical dry-running vacuum pumps. Specifically, it is necessary to ensure that individual components such as gears and upper and lower bearings are reliably and effectively lubricated with oil, and at the same time, to ensure that the oil does not leak into other parts of the vacuum pump system.

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

[0004] [[ID=X]] Known solutions for lubricating vacuum pump bearings include the use of grease.

[0005] One drawback of known solutions for lubricating other components such as the bearings and gears of a vacuum pump is the need to frequently monitor the condition of the lubricated components, because the risk of damage and / or failure of the vacuum system due to under- or over-greasing, the use of hardened or old grease, and the possibility of grease contamination is very high. [[ID=2X]]

[0006] Another drawback is the high maintenance cost.

Summary of the Invention

[0007] The object of the present invention is to provide a reliable and effective oil lubrication solution for vacuum pumps that reduces the risk of vacuum pump failure caused by insufficient lubrication of the bearings and / or gears of the vacuum pump. [Means for solving the problem]

[0008] This objective is achieved by the centrifugal oil pump device described in claim 1, and by a vacuum pump equipped with the centrifugal oil pump device according to claim 1 as described in 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 located below the at least one opening, the oil reservoir positioned above an oil pump impeller, and such that oil is supplied downward toward the oil pump impeller through 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 acting centrifugal force toward a volute so that the oil flows out of the volute under pressure; and a non-rotating shielding member surrounding the oil pump drive shaft, the shielding 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 within the centrifugal oil pump and sent to the respective vacuum pump components for lubrication.

[0010] Preferably, the shielding member comprises a shielding element extending axially along the rotation axis of the oil pump drive shaft. In other words, the shielding member forms a collar or sleeve around its outer surface along the rotation axis of the oil pump drive shaft. This has the advantage of preventing oil from coming into contact with the surface of the rotating oil pump drive shaft and thus preventing it from being subjected to centrifugal force that pushes it away from the oil pump inlet, and consequently preventing oil depletion.

[0011] Preferably, the shielding member comprises at least two or three radial shielding vanes. More preferably, the shielding member comprises three or four or more radial shielding vanes, and most preferably four or five or more radial shielding vanes. This can have the further advantage that when oil comes into contact with the rotating oil pump drive shaft, the rotating oil is obstructed by the radial shielding vanes. The rotational flow is blocked, and the radial shielding vanes function as flow resistance.

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

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

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

[0015] Preferably, at least one opening is radially positioned around the oil pump drive shaft and can be radially adjacent to the shield element, preferably located below the radial shield vane. At least one opening can be an annular opening radially positioned around the oil pump drive shaft.

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

[0017] Preferably, each impeller vane has a first end and a second end, with each first end positioned tangentially to the volute. This has the advantage of reducing the 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, and the cross-sectional area of ​​the volute increases as the distance to the oil pump outlet decreases. This can have the advantage that as the oil approaches the oil pump outlet, the kinetic energy of the oil is converted into static pressure energy.

[0019] According to a second aspect of the present invention, a centrifugal oil pump device for a vacuum pump preferably comprises: an oil pump inlet located at the center of an oil pump impeller coupled to a pump oil pump drive shaft, wherein the oil pump drive shaft is coupled to a vacuum pump drive shaft, and the oil pump impeller acts centrifugal force toward a volute, causing the oil to exit the volute under pressure; and a non-rotating shielding member surrounding the oil pump drive shaft. In this way, oil can be supplied to the oil pump inlet, then pressurized within the centrifugal oil pump, and delivered to each vacuum pump component for lubrication without being subjected to centrifugal force acting at a distance by the rotating vacuum pump drive shaft.

[0020] Preferably, a gap exists between the shielding member and the oil pump drive shaft to allow the volute to pass through. This has the advantage of preventing foaming of the oil due to gas molecules contained in the oil.

[0021] Preferably, the shielding member extends axially along the rotation axis of the oil pump drive shaft. In other words, the shielding member forms a collar or sleeve around its outer surface along the rotation axis of the oil pump drive shaft. This 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, a vacuum pump is provided that includes a centrifugal oil pump device according to a 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 this respect, the oil pump drive shaft is coupled to the vacuum pump drive shaft. In this way, individual components of the vacuum pump, such as bearings and gears, can be reliably lubricated with oil, and as a result, there is an advantage in that failures or downtime due to wear can be reduced.

[0023] Preferably, the vacuum pump equipped with a centrifugal oil pump device 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. This has the advantage of reducing manufacturing costs.

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

[0026] According to a fourth aspect of the present invention, there is provided a vacuum pump provided with the centrifugal oil pump device according to the second aspect of the present invention. The vacuum pump includes a vacuum pump casing, a vacuum pump motor, at least one pump rotor, a vacuum pump bearing that supports the pump rotor, and a vacuum pump drive shaft. In that regard, the oil pump drive shaft is coupled to the vacuum pump drive shaft. In this way, individual components such as the bearings and gears of the vacuum pump can be reliably lubricated with oil, and as a result, failures or outages due to wear can be reduced.

[0027] Preferably, the vacuum pump includes an oil reservoir extending radially around the oil pump drive shaft, and the oil reservoir includes at least one opening. At least one opening of the oil reservoir is connected to the oil pump inlet by a connecting member. This can have the advantage that at least one opening of the oil reservoir can be arranged away from 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. This can have the advantages of reducing manufacturing costs, improving the reliability of the system due to a reduction in the number of components, and reducing the respective risks of failures on the joints between components.

[0029] Preferably, the vacuum pump includes at least one vacuum pump gear, at least one upper vacuum pump bearing, and at least one lower vacuum pump bearing, and the centrifugal oil pump device supplies oil for lubricating at least one vacuum pump gear and / or at least one upper vacuum pump bearing and / or at least one lower vacuum pump bearing. This has the advantage that the maintenance cost can be reduced because these components can be lubricated with oil, and the continuous and reliable operation of the vacuum pump can be guaranteed.

[0030] Hereinafter, the present invention will be described in more detail by preferred embodiments with reference to the accompanying drawings.

Brief Description of the Drawings

[0031] [Figure 1A] An embodiment according to a first aspect of the present invention shows a centrifugal oil pump device for a vacuum pump, preferably. [Figure 1B] A plan view of a centrifugal oil pump device for a vacuum pump, preferably shown in FIG. 1A, is shown. [Figure 1C] A detailed view of an impeller and a volute of an oil pump device according to an embodiment of a first aspect of the present invention is shown. [Figure 2A] An embodiment according to a second aspect of the present invention shows a centrifugal oil pump device for a vacuum pump, preferably. [Figure 2B] A detailed view of an impeller and a volute of an oil pump device according to an embodiment of a second aspect of the present invention is shown. [Figure 3] A vacuum pump equipped with a centrifugal oil pump device according to a first aspect or a second aspect of the present invention is shown.

Modes for Carrying Out the Invention

[0032] A centrifugal oil pump device 100, as shown in Figure 1A, includes an oil reservoir 10 extending radially around an oil pump drive shaft 50. The oil reservoir 10 has an annular opening 11, which is 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 an annular one, as shown in Figure 1A. Furthermore, the number of openings 11 can be two or more. As can be seen from Figure 1A, the oil reservoir 10 is located above the oil pump inlet 30. Therefore, in the embodiment shown in Figure 1A, gravity-fed oil is supplied from the reservoir 10 through its opening 11 to below the oil pump inlet 30.

[0033] As shown in Figure 1A, the oil pump drive shaft 50 is coupled to the vacuum pump drive shaft 20. Furthermore, the oil pump impeller 40 is coupled to the oil pump drive shaft 50. During vacuum pump operation, the oil pump drive shaft 50 is driven by the rotating vacuum pump drive shaft 20, and the oil pump impeller 40 exerts centrifugal force on the oil toward the volute 60, causing the oil to exit the volute 60 toward the oil pump outlet 80 (not shown in Figure 1A) under pressure.

[0034] Furthermore, the centrifugal oil pump device 100, as shown in Figure 1A, includes 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 the operation of the vacuum pump. In the embodiment shown in Figure 1A, the shield member 70 includes a shield element 71 that extends axially along the rotation axis R of the oil pump drive shaft 50. In this way, the shield element 71 functions as a seal for the oil pump drive shaft 50, preventing oil from coming into contact with the oil pump drive shaft 50, and consequently preventing the oil from rotating due to the rotation of the oil pump drive shaft 50 during the operation of the vacuum pump.

[0035] As shown in Figure 1B, the shielding member further comprises three radial shielding vanes 72. However, the number of radial shielding vanes 72 may differ in other embodiments and can be two or any number more. The three radial shielding vanes 72 provide further safety measures for the oil pump device. If oil were to come into contact with the rotating oil pump drive shaft 50 and rotational energy were transferred to the oil, the oil would rotate away from the center of the oil pump inlet, the oil surface would become uneven, and the flow of oil to the oil pump inlet could be obstructed. Therefore, to prevent the above-mentioned effects of oil rotation, the radial shielding vanes 72 block the oil, and the oil transfers its rotational and / or kinetic energy to the shielding vanes 72. Furthermore, the radial shielding vanes 72 provide mechanical support to the shielding element 71, and as a result hold the shielding element 71 in its respective position.

[0036] Figure 1C shows a detailed view of the impeller 40 and volute 60 of the centrifugal oil pump device of the embodiment shown in Figure 1A. The oil pump impeller 40 shown in Figure 1C comprises four impeller vanes 41 having a non-zero radius of curvature. However, the number of impeller vanes 41 may differ in other embodiments, being any number of two or more, and / or not having a non-zero radius of curvature. Furthermore, each of the impeller vanes 41 comprises a first end 411 and a second end 412, the first end 411 of each being tangentially positioned in the volute 60, and the second end 412 of each facing toward the oil pump drive shaft 50 but not coupled to it. Oil is supplied from the oil pump inlet 30 (see Figure 1A) into the divided space between the oil pump impeller 40 and the four impeller vanes 41. As the oil pump impeller 40 rotates, the oil is accelerated by the impeller vanes 41 and discharged into the curved volute 60 with high kinetic energy.

[0037] As shown in Figure 1C, the cross-sectional area of ​​the volute 60 increases as the distance to the oil pump outlet 80 decreases. In this way, the kinetic energy of the oil decreases as the distance to the oil pump outlet 80 decreases, but the oil pressure increases as the distance to the oil pump outlet 80 decreases, allowing the oil to be discharged from the centrifugal oil pump device 100 under high pressure.

[0038] As shown in Figure 2A, the centrifugal oil pump device 200 includes a vacuum pump drive shaft 120 coupled to an oil pump drive shaft 150. Furthermore, it includes an oil pump impeller 140 coupled to the oil pump drive shaft 150, with an oil pump inlet 130 located at the center of the oil pump impeller 140. As can be seen from Figure 2A, oil is supplied upward from the oil reservoir to the oil pump inlet 130 via a connecting member 190, which is like a flow path. The connecting member 190 is positioned offset from the vacuum pump drive shaft 120 and is therefore not affected by the rotation of the vacuum pump drive shaft 120. Thus, oil can be supplied from the oil reservoir to the centrifugal oil pump device 200 without interruption. During operation, as the oil pump drive shaft 150 is rotated by the rotating vacuum pump drive shaft 120, the oil is supplied through the oil pump inlet 130 to the impeller passage 141, which is provided, for example, as a drilled hole between the impeller vanes 142, as shown in Figure 2B and described in detail below, and is accelerated by the impeller vanes 142 toward the volute 160. The oil then proceeds toward the oil pump outlet 180 through the curved volute 160. 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 Figure 2A, the centrifugal oil pump device further includes a shielding member 170 extending radially and longitudinally around the oil pump drive shaft 150, which shields the oil pump drive shaft 150 during operation so that the oil is not subjected to the centrifugal force directed away from the rotating oil pump drive shaft 150. Furthermore, a gap 171 exists between the shielding member 170 and the oil pump drive shaft 150 for ventilation of the volute 160. Therefore, if the accelerated oil foams due to gas particles contained therein, the gap 171 allows ventilation so as to reduce the foaming of the oil and prevent malfunction of the centrifugal oil pump device 200 due to foaming.

[0040] Figure 2B shows a detailed view of the impeller 140 and volute 160 of the embodiment shown in Figure 2A. The oil pump impeller 140 shown in Figure 2B comprises four impeller passages 141. However, the number of impeller passages 141 may differ in other embodiments and may be any number of two or more. Furthermore, each of the impeller passages 141 comprises a first end 1411 and a second end 1412, with each first end 1411 positioned toward the volute 160 and each second end 1412 It is facing the oil pump inlet 130. Oil is supplied from the oil pump inlet 130 to the impeller passage 141 or impeller hole. When the oil pump impeller 140 rotates, the oil is subjected to centrifugal force by the impeller 140 toward the volute 160 and is discharged into the volute 160 with high kinetic energy.

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

[0042] Figure 3 shows a vacuum pump 300 equipped with a centrifugal oil pump device 400 according to the embodiment shown in Figures 1A, 1B, 1C or 2A, 2B. In the embodiment shown in Figure 3, the vacuum pump 300 includes a motor 500 that drives the vacuum pump drive shafts 20, 120. Furthermore, an upper bearing 321 and a lower bearing 322 are located at the opposite end of the vacuum pump rotor 340. In addition, the vacuum pump 300 is configured to allow synchronization with a second vacuum pump drive shaft, such as a screw pump, scroll pump, or Roots pump, in particular, with the vacuum pump rotor. 340 The end of the bearing may be provided with at least one lower gear 332. The gear 332 may also be located either at the top or the bottom. However, the present invention is not limited to a specific arrangement of bearings 321, 322 and / or at least one gear 332. During operation, the centrifugal oil pump device 400 discharges pressurized oil to the oil pump outlets 80, 180, which is supplied to the upper bearing 321 and lower bearing 322 via the connecting member 350. Another connecting member 360 supplies oil from the upper bearing 321 to the oil reservoir. 10 Return to the lower bearing 322 and lower gear 332, and the oil will drain into the oil reservoir. 10 The oil is discharged to 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] Therefore, a centrifugal oil pump device is provided for effectively and reliably lubricating the individual components of a vacuum pump. [Explanation of symbols]

[0044] 100, 200 Centrifugal Oil Pump System 10 Oil reservoir 11 Annular opening 20, 120 Vacuum pump drive shaft 30, 130 Oil pump inlet 40, 140 Oil pump impeller 41 Imperaven 411 First end of the impera vane 412 The second end of the impera vane 50, 150 Oil pump drive shaft 60, 160 volutes 70, 170 Shielding members 71 Shield elements 72 Radial Shield Vanes 80, 180 Oil pump outlet 141 Impeller flow path 1411 First end of the impeller flow path 1412 Second end of the impeller flow path 171 Gap 190 Connecting Member 300 Vacuum Pump 321 Vacuum pump upper bearing 322 Vacuum pump lower bearing 332 Vacuum pump gear 340 Vacuum pump rotor 350 Connecting Members 360 Connecting Member 400 Centrifugal Oil Pump System 500 Vacuum Pump Motor

Claims

1. A centrifugal oil pump device for a vacuum pump, An oil reservoir having at least one opening and extending radially around the vacuum pump drive shaft, An oil pump inlet located below the at least one opening, wherein the oil reservoir is located above the oil pump impeller, and oil is supplied downward toward the oil pump impeller through the at least one opening and the oil pump inlet, The oil pump drive shaft is coupled to the aforementioned vacuum pump drive shaft, An oil pump impeller coupled to the oil pump drive shaft, wherein the oil pump impeller applies centrifugal force to the oil toward a volute, causing the oil to exit the volute under pressure. A non-rotating shielding member surrounding the oil pump drive shaft, wherein the shielding member prevents the oil from rotating due to the rotation of the oil pump drive shaft, Equipped with, The shield member comprises at least two radial shield vanes, A centrifugal oil pump device wherein the at least one opening is located below the radial shield vane.

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

3. The centrifugal oil pump device according to claim 2, wherein the at least one opening is radially arranged around the oil pump drive shaft and is radially adjacent to the shield element.

4. The centrifugal oil pump device according to claim 2, wherein the at least one opening is an annular opening arranged radially around the oil pump drive shaft.

5. The centrifugal oil pump device according to claim 1, wherein the radial shield vane extends radially from the shield member.

6. The centrifugal oil pump device according to claim 1, wherein the oil pump impeller comprises at least two impeller vanes.

7. The centrifugal oil pump device according to claim 6, wherein the impeller vane has a non-zero radius of curvature.

8. The centrifugal oil pump device according to claim 1, wherein the volute is connected to the oil pump outlet, and the cross-sectional area of ​​the volute increases as the distance to the oil pump outlet decreases.

9. A vacuum pump comprising the centrifugal oil pump device described in claim 1.

10. The vacuum pump according to claim 9, wherein the oil pump drive shaft and the vacuum pump drive shaft are integrally formed.

11. The vacuum pump according to claim 9, wherein the vacuum pump comprises at least one vacuum pump gear, at least one upper vacuum pump bearing, and at least one lower vacuum pump bearing, and the centrifugal oil pump device supplies oil for lubricating the at least one vacuum pump gear and / or the at least one upper vacuum pump bearing and / or the at least one lower vacuum pump bearing.

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