WO2023232803A1

WO2023232803A1 - Vacuum pump

Info

Publication number: WO2023232803A1
Application number: PCT/EP2023/064435
Authority: WO
Inventors: Patrick Fournier; Benoit REYNAUD; Frederic Piu; Christian MOULIN; Augustin GOURE; Christophe DESPESSE; Mickael SERAYET
Original assignee: Leybold France Sas
Priority date: 2022-05-30
Filing date: 2023-05-30
Publication date: 2023-12-07

Abstract

A rotary vane vacuum pump comprising a pump system (20), a control unit (10), a fan (50) and a housing (52) is disclosed. The pump system comprises a stator and a rotor mounted within the stator, the rotor being configured to cooperate with the stator during operation of the vacuum pump to pump gas from an inlet to an outlet of the vacuum pump. The pump system further comprises a motor (60) configured to drive the rotor. The control unit (10) comprises control circuitry housed within a casing, the control unit being mounted adjacent to the pump system. The housing (52) is arranged to at least partially surround the fan (50) and is configured to direct air flow from the fan over an outer surface of the pump system and an outer surface of the control circuitry (10).

Description

VACUUM PUMP

FIELD OF THE INVENTION

The field of the invention relates to the field of rotary vane vacuum pumps and a method of cooling such pumps.

BACKGROUND

Rotary vane vacuum pumps typically comprise a cooling system for cooling the vacuum pump. The cooling system may comprise two cooling fans. One fan is configured to pass cooling air over the vacuum generator and the motor configured to drive the vacuum generator. A second fan is configured to pass cooling air through a control unit which houses the control circuitry for controlling operation of the vacuum pump.

It would be desirable to provide an improved cooling system for a rotary vane vacuum pump.

SUMMARY

According to a first aspect of the invention, there is provided a rotary vane vacuum pump, comprising: a pump system comprising: a stator; a rotor mounted within the stator and configured to cooperate with the stator during operation of the vacuum pump to pump gas from an inlet to an outlet of the vacuum pump; and a motor configured to drive the rotor; a control unit comprising control circuitry housed within a casing, said control unit being mounted adjacent to said pump system; a fan; and a housing at least partially surrounding the fan, the housing being configured to direct air flow from the fan over an outer surface of the pump system and an outer surface of the control circuitry.

A housing may be used, which when arranged appropriately, directs air flow from one cooling fan over both the pump system and the control circuitry. This may provide effective cooling of each of the pump system and the control unit and obviate the need for cooling fans dedicated to each. Therefore, arrangements provide a simplified cooling system having fewer components which could provide a cost, power, servicing and/or weight saving.

In some embodiments, the housing comprises an inlet upstream of the fan for allowing cooling air to enter the housing, wherein the inlet comprises at least one aperture through a surface of the housing facing the fan.

In some embodiments, the surface of the housing facing the fan is distanced from the fan by at least 10% of the radius of the fan, preferably between 14 and 17%.

Typically, a cooling fan for cooling a pump system is mounted within a housing of a rotary vane vacuum pump immediately adjacent a cooling air inlet defined in the housing. The distance between the fan and the housing is often minimised such that the vacuum pump is compact. However, by distancing the fan and the inlet, it has been found that air intake can be improved which can be particularly beneficial when only one fan is being used to pass air over both the vacuum pump system and the control circuitry. Additionally, the noise generated by the cooling system can be reduced by increasing the distance between the fan and the housing and by only having a single fan. It will be appreciated that there is a balance between improving the cooling system and increasing the size of the vacuum pump which may be for use in confined spaces.

In some embodiments, the surface of the housing facing the fan is distanced at least 20mm away from the fan. The fan radius may be between 120mm and 140mm.

In some embodiments, the inlet further comprises at least one aperture through at least one surface adjacent to the surface of the housing facing the fan and extending towards the fan.

Conventional inlets for cooling air are defined through the housing in a plane substantially perpendicular to the axis of rotation of the fan such that the inlet is facing the fan. Typically, the inlet is defined in an end surface of the housing.

Providing an inlet with at least one aperture through at least one surface adjacent to the conventional surface facing the fan can improve air intake for the cooling system because the surface area of the inlet can be increased. Furthermore, air may be drawn into the housing by the fan from more than one direction which may improve performance of the cooling system in confined spaces. In one arrangement, the inlet comprises apertures defined in a side wall of the housing.

Additionally or alternatively, the inlet may comprise apertures in a top or bottom wall of the housing. When combined with distancing the inlet surface facing the fan by at least 10% of the radius of the fan, these additional apertures can be provided on the side of the housing where the housing has been extended to create the distancing.

In some embodiments, the housing comprises an exhaust downstream of the fan for allowing cooling air to exit the housing, wherein the exhaust comprises at least one aperture through a second surface of the housing facing the fan.

In some embodiments, the exhaust further comprises at least one aperture through at least one surface adjacent to the second surface of the housing facing the fan and extending towards the fan.

Similar to providing one or more inlet apertures on a side wall of the housing, airflow out of the pump may be facilitated by, in addition to an exhaust on a surface facing the fan, the provision of at least one aperture through at least one surface adjacent to the surface facing the fan. This can increase the surface area defined by the exhaust allowing greater air flow out of the vacuum pump.

In some embodiments, the vacuum pump comprises a fluid communication path between the control circuitry and the pump system, such that cooling air flowing over the outer surface of the control circuitry is exhausted via the outer surface of the pump system. In this arrangement, cooling air passed over the control circuitry can be introduced into the air flow passing over the pump system to help cool the pump system after passing over the control circuitry. This may allow substantially all of the cooling air to be exhausted through a single exhaust defined in the pump housing.

In some embodiments, the fluid communication path comprises at least one aperture in a surface of the casing of the control circuitry adjacent to the pump system. This arrangement may provide a simple and effective way to create a fluid communication path between the control circuitry and the pump system.

Conventional cooling systems comprising a dedicated fan for cooling the control circuitry have an exhaust defined in the casing of the control unit. This exhaust is typically placed on an end surface of the casing which is accessible to the user. This poses a safety risk because the exhaust provides an access route to electronic components, i.e. , the control circuitry. For this reason, regulations govern the allowable dimensions for the apertures of this exhaust. The present arrangement can obviate the need for such an exhaust because the cooling air is redirected towards the pump system rather than being exhausted directly from the casing of the control unit and as such the flow path from the control circuitry is shielded by the pump system. As a result, protection of the electronic components from inadvertent access can be improved because the at least one aperture providing the fluid communication path between the control circuitry and the pump system is not accessible to the pump operator. Moreover, being inaccessible to the pump operator, the regulations governing the allowable dimensions of conventional control unit air flow apertures may not be applicable here which can increase design freedom.

In some embodiments, the housing and the outer surface of the pump system define a flow path for cooling air from the fan to the exhaust of the housing. Cooling air may be blown by the fan between the housing and the outer surface of the pump system to cool the pump system.

In some embodiments, the housing comprises at least one formation extending into the flow path to narrow the flow path to increase the speed of air flow through the flow path.

Increasing the speed of air flow over the pump system may improve the cooling effect provided by the air. In this arrangement, the at least one formation is configured to increase air flow speed by gradually narrowing the flow path between the housing and the pump system.

In this embodiment, the at least one formation is arranged to increase the speed of air flow from the fan over at least a portion of the pump system, preferably over the motor. Thus, any improved cooling effect provided by the increased speed of air flow generated by the at least one formation can be concentrated on the components of the vacuum pump which have particular cooling requirements during operation of the vacuum pump, namely, the motor and the vacuum generator.

In some embodiments, the at least one formation comprises at least one aperture to define a portion of the fluid communication path between the control circuitry and the pump system. In this way, impedance of the airflow between the control circuitry and the pump system by the at least one formation can be reduced.

In some embodiments, the vacuum pump comprises an oil-sealed vacuum pump.

According to a second aspect of the invention, there is provided a modular system comprising: a vacuum pump according to the first aspect, said vacuum pump comprising a lubricant sealed vacuum pump comprising a lubricant reservoir and a vacuum generator comprising said stator and said rotor; and a support frame, said vacuum pump being mounted on said support frame supporting said vacuum pump above a surface; said support frame comprising an upper mounting means configured for supporting said vacuum generator, said lubricant reservoir and said motor; and a lower level configured to receive said control circuitry.

The support frame supports the vacuum generator above the control circuitry and the housing is configured to direct cooling air over both the vacuum generator and the control circuitry.

According to a third aspect of the invention, there is provided a method of cooling a vacuum pump according to a first aspect, the method comprising: arranging a housing around the pump system and control circuitry; and rotating a fan of said vacuum pump such that air flow generated by said fan is directed over both said pump system and said control circuitry.

Configuring the housing and the fan in such a way as to blow cooling air over both the control circuitry and pump system may obviate the need for multiple cooling fans.

Further particular and preferred aspects are set out in the accompanying independent and dependent claims. Features of the dependent claims may be combined with features of the independent claims as appropriate, and in combinations other than those explicitly set out in the claims.

Where an apparatus feature is described as being operable to provide a function, it will be appreciated that this includes an apparatus feature which provides that function or which is adapted or configured to provide that function.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will now be described further, with reference to the accompanying drawings, in which: Figure 1 shows a vacuum pump according to an embodiment;

Figure 2 shows a vacuum pump according to an embodiment;

Figure 3 shows an inlet of a vacuum pump according to an embodiment;

Figure 4 shows a vacuum pump according to an embodiment with the housing omitted;

Figure 5 shows a support frame for a modular system according to an embodiment;

Figure 6 shows a modular system according to an embodiment;

Figure 7 shows a control unit mounted within a support frame for a modular system according to an embodiment; and

Figure 8 illustrates steps in a method according to an embodiment.

DESCRIPTION OF THE EMBODIMENTS

Before discussing the embodiments in any more detail, first an overview will be provided.

Rotary vane vacuum pumps comprise: a pump system including a vacuum generator and a motor; and a control circuitry configured to control operation of the pump system. The vacuum generator comprises a stator and a rotor housed within the stator. The rotor is configured to cooperate with the stator to pump fluid from an inlet to an outlet of the vacuum pump. Embodiments provide a cooling system for such a vacuum pump comprising a single fan configured to cool both the pump system and the control circuitry. Cooling air from the fan is directed over an outer surface of the pump system and an outer surface of the control circuitry by the housing. Conventionally, the pump system and the control circuitry are cooled by different fans. Embodiments therefore provide a simple solution to reduce the number of fans required to cool the vacuum pump. This may reduce the cost and complexity of the vacuum pump.

Some embodiments provide an inlet for cooling air defined by the housing which is distanced from the fan by at least 10% of the radius of the fan, preferably between 14 and 17%. Conventionally, inlet apertures for cooling air that are defined in the pump housing are very close to the fan to keep the vacuum pump compact. However, without a sufficient gap between the inlet and the fan, air intake can be impeded. Therefore, some embodiments extend the space between the housing and the fan such that the inlet is more distanced from the fan to improve air intake. Increasing the distance between the inlet and the fan can also reduce the noise generated by the cooling system.

The inlet and/or exhaust for the cooling air may comprise apertures in a side, top or bottom wall of the housing in addition to one or more apertures on a surface facing the fan. Conventionally, inlets and outlets are solely located on the surfaces of the housing facing the fan (parallel to the fan). Extending the housing to distance the inlet from the fan to improve the intake of cooling air, provides an opportunity to provide additional inlet apertures on the side, top or bottom walls of the vacuum pump for the portion where the housing has been extended. By increasing the number of apertures defining the inlet, the inlet surface area can be increased allowing more cooling air to be drawn into the housing for cooling the vacuum pump.

In some arrangements, there is a fluid communication path between the control circuitry and the pump system. This may allow air that is initially directed over the control circuitry to be merged with the air which was initially directed over the pump system. Such an arrangement means that all the cooling air can be efficiently used for cooling and expelled through a single exhaust.

In some embodiments, the housing comprises one or more formations which extend into the flow path defined between the pump system and the housing. The formations are designed to narrow the flow path such that air flow speed through the pump can be increased. The at least one formation may be a simple and cost-effective way to increase the air flow speed through the housing because the housing is generally made from a relatively cheap and workable material such as plastic. Figure 1 schematically shows a rotary vane oil-sealed vacuum pump 1 according to an embodiment comprising: a vacuum generator 20 including a rotor and a stator which cooperate to pump fluid from an inlet to an outlet of the vacuum pump 1 as is known; a motor 60 for driving the rotor; control circuitry 10 configured to control operation of the vacuum pump; housing 52; and fan 50 for passing cooling air over the components of the vacuum pump 1. The vacuum generator 20 and the motor 60 together may be referred to as a pump system.

The pump system is supported within the housing 52 on an upper level of a support frame 5. The control circuitry 10 is also supported by the frame 5 but at a lower level. The fan 50 is mounted within the housing 52 and is arranged such that cooling air blown by the fan can be passed over the both the pump system and the control circuitry 10 as shown by the arrows. In some embodiments, the fan 50 is driven by a shaft of the motor 60.

Air is drawn into the housing 52 by the fan 50 via an inlet 54 defined in the housing 52 upstream of the fan 50. The inlet 54 comprises an array of apertures 55a shown in Figure 3 extending through a surface of the housing 52 which faces the fan 50 (the end face of the housing 52). The inlet 54 further comprises an array of apertures 55b on a face immediately adjacent the surface of the housing 52 which faces the fan (on the side face of the housing 52). It will be appreciated that any number of apertures may be provided on the surface facing the fan and the surface adjacent that. For example, a single aperture may be provided on each, multiple apertures on one surface and one aperture on the other surface, or multiple apertures on each as shown in Figure 3. The apertures may form shapes other than those depicted in Figure 3.

The surface facing the fan 50 on which the inlet apertures 55a are defined is distanced from the fan 50 by at least 10% of the radius of the fan, preferably between 14 and 17%. By distancing the fan 50 from the inlet, a space is created between the fan and the inlet. This space can improve air intake and also reduce noise created by the cooling system. Figure 2 schematically shows a vacuum pump and the cooling air flow according to an embodiment. A flow path for cooling air directed towards the pump system (indicated by the top arrow in Figures 1 and 2 ) is defined between the housing 52 and the outer surface of the pump system. In this embodiment, the housing 52 comprises at least one formation 53 extending into the flow path which narrows the flow path such that the speed of air flow over the vacuum pump components can be increased to improve its cooling effect. The at least one formation 53 is arranged to increase the speed of air flowing over at least a portion of the pump system, preferably over the motor 60. The air is exhausted via an exhaust 56 defined in the housing 52 downstream of the fan 50. The exhaust 56 may comprise substantially the same aperture arrangement as the inlet 54 shown in Figure 2 or it may differ. The exhaust 56 may comprise an array of apertures on a surface facing the fan 50 (the end wall of the housing 52) and an array of apertures on a surface immediately adjacent to this surface (the side wall of the housing 52). It will be appreciated that the exhaust 56 may comprise any number of apertures. In some embodiments, the exhaust 56 may comprise one or more apertures on the surface facing the fan 50 and none on the side walls of the housing 52.

For cooling air directed towards the control circuitry 10 (indicated by the bottom arrow in Figures 1 and 2), a flow path is defined between an outer surface of the control circuitry 10 and the casing 14. This air is then reintroduced into the flow path defined between the pump system and the housing 52 via an aperture 15 defined in the surface of the casing 14 adjacent and facing the pump system such that all of the cooling air is exhausted via the exhaust 56 defined in the housing 52. The fluid communication path between the control circuitry 10 and the pump system is partly defined by an aperture 53a in the at least one formation 53 shown in Figure 2 such that some of the cooling air can help cool both the control circuitry 10 and the pump system. Where a dedicated fan is used for cooling the control circuitry of known vacuum pumps, the casing of the control unit includes an exhaust defined in an end surface of the casing which may be accessible to vacuum pump operators. There may be regulations which govern the size of apertures in casings for electrical components aimed at reducing the likelihood of the ingress of material or the operator’s fingers. . By defining a fluid communication path between the control circuitry and the pump system, the cooling air may be exhausted via the pump system removing the need for an exhaust in the casing 14 and improving cooling air flow. This may reduce the number of access points to the electrical components of the control unit. The present arrangement provides an aperture 15 on a surface of the casing 14 adjacent to and facing the pump system. As a result, this aperture is not accessible to vacuum pump operators once the vacuum pump 1 has been assembled. Given that it is not accessible, the aperture 15 may not be subject to the same stringent regulations as known control unit exhausts and so design freedom may be increased.

Figure 3 shows the housing 52 around an end of the rotary vane pump with air inlet surface 54 having inlet apertures 55a and the extension to the side wall with air inlet apertures 55b.

Figure 4 shows a vacuum pump 1 with a portion of the housing 52 that covers the motor 60 omitted for clarity. The control circuitry 10 of Figure 1 forms a part of control unit 12 which also comprises a casing 14 for housing the control circuitry 10. The control unit 12 is configured to control operation of the vacuum pump 1 using the control circuitry 10.

Figure 5 shows a more detailed view of the support frame 5. The frame 5 includes a surface 4 on which the pump system is mounted using upper mounting means 3 and a lower level 6 for supporting the control circuitry 10. Side walls 9 interconnect the surface 4 and the lower level 6. The frame 5 further includes feet 7 extending from the side walls 9 at one end of the frame 5. At the other end of the frame 5, wheels 8 for facilitating movement of the vacuum pump 1 extend from the side walls 9.

Figure 6 shows the control circuitry 10 being supported on the lower level 6 and the vacuum generator 20, together with a lubricant reservoir 30 of the vacuum pump 1 , being supported on the surface 4 of the frame 5. The vacuum generator 20 and the lubricant reservoir 30 are supported on a vibration damper 40 to reduce vibrations being transferred from the vacuum generator 20 to the frame 5 and control unit 10.

Figure 7 shows the control unit 12 mounted within the frame 5. The frame 5 is designed such that it does not obstruct the aperture 15 defined in the top surface of the casing 14 of the control unit 12.

Figure 8 illustrates a method for cooling a vacuum pump according to an embodiment. In step 101 a housing is arranged around the pump system and control circuitry. In step 102 a fan within the housing is started and cooling air generated by the fan is directed by the housing over both the pump system and the control circuitry, so that a single fan is used to cool at least a portion of a pump system and control circuitry of the vacuum pump.

Although illustrative embodiments of the invention have been disclosed in detail herein, with reference to the accompanying drawings, it is understood that the invention is not limited to the precise embodiment and that various changes and modifications can be effected therein by one skilled in the art without departing from the scope of the invention as defined by the appended claims and their equivalents. REFERENCE SIGNS

1 Vacuum Pump

3 Upper Mounting Means

4 Surface

5 Support Frame

6 Lower Level

7 Feet

8 Wheel

9 Upper Mounting Means

10 Control Circuitry

12 Control Unit

14 Casing

15 Aperture

20 Vacuum Generator

30 Lubricant Reservoir

40 Vibration Damper

50 Fan

52 Housing

53 Formation

53a Aperture

54 Inlet

55a, 55b Inlet Aperture

56 Exhaust

60 Motor

Claims

1 . A rotary vane vacuum pump, comprising: a pump system comprising: a stator; a rotor mounted within the stator and configured to cooperate with the stator during operation of the vacuum pump to pump gas from an inlet to an outlet of the vacuum pump; and a motor configured to drive the rotor; a control unit comprising control circuitry housed within a casing, said control unit being mounted adjacent to said pump system; a fan; and a housing at least partially surrounding the fan, the housing being configured to direct air flow from the fan over an outer surface of the pump system and an outer surface of the control circuitry.

2. A vacuum pump according to claim 1 , wherein the housing comprises an inlet upstream of the fan for allowing cooling air to enter the housing, wherein the inlet comprises at least one aperture through a surface of the housing facing the fan.

3. A vacuum pump according to claim 2, wherein the surface of the housing facing the fan is distanced from the fan by at least 10% of the radius of the fan, preferably between 14 and 17%.

4. A vacuum pump according to claim 2 or claim 3, wherein the inlet further comprises at least one aperture through at least one surface adjacent to the surface of the housing facing the fan and extending towards the fan.

5. A vacuum pump according to any one of claims 2 to 4, wherein the housing comprises an exhaust downstream of the fan for allowing cooling air to exit the housing, wherein the exhaust comprises at least one aperture through a second surface of the housing facing the fan.

6. A vacuum pump according to claim 5, wherein the exhaust further comprises at least one aperture through at least one surface adjacent to the second surface of the housing facing the fan and extending towards the fan.

7. A vacuum pump according to any preceding claim, further comprising a fluid communication path between the control circuitry and the pump system, such that cooling air flowing over the outer surface of the control circuitry is exhausted via the outer surface of the pump system.

8. A vacuum pump according to claim 7, wherein the fluid communication path comprises at least one aperture in a surface of the casing of the control circuitry adjacent to the pump system.

9. A vacuum pump according to claim 5, or any one of claims 6 to 8 when dependent on claim 5, wherein the housing and the outer surface of the pump system define a flow path for cooling air from the fan to the exhaust of the housing.

10. A vacuum pump according to claim 9, wherein the housing comprises at least one formation extending into the flow path to narrow the flow path to increase the speed of air flow through the flow path.

11 . A vacuum pump according to claim 10, wherein the at least one formation is arranged to increase the speed of air flow from the fan over at least a portion of the pump system, preferably over the motor.

12. A vacuum pump according to claim 11 when dependent on claim 7, wherein the at least one formation comprises at least one aperture to define a portion of the fluid communication path between the control circuitry and the pump system.

13. A vacuum pump according to any preceding claim, comprising an oil- sealed vacuum pump.

14. A modular system comprising: a vacuum pump according to any preceding claim, said vacuum pump comprising a lubricant sealed vacuum pump comprising a lubricant reservoir and a vacuum generator comprising said stator and said rotor; and a support frame, said vacuum pump being mounted on said support frame supporting said vacuum pump above a surface; said support frame comprising an upper mounting means configured for supporting said vacuum generator, said lubricant reservoir and said motor; and a lower level configured to receive said control circuitry.

15. A method of cooling a vacuum pump according to any preceding claim comprising: arranging the housing around the pump system and control circuitry; and rotating the fan of said vacuum pump such that air flow generated by said fan is directed over both said pump system and said control circuitry.