AU2013387156B2

AU2013387156B2 - Vane-type rotary vacuum pump

Info

Publication number: AU2013387156B2
Application number: AU2013387156A
Authority: AU
Inventors: Didier Muller; Christian Schaller
Original assignee: Ateliers Busch SA
Current assignee: Ateliers Busch SA
Priority date: 2013-04-19
Filing date: 2013-04-19
Publication date: 2017-06-29
Anticipated expiration: 2033-04-19
Also published as: HK1214325A1; EP2986821B1; BR112015026027A2; WO2014169962A1; PT2986821T; TWI660128B; BR112015026027B1; JP2016519243A; EP2986821A1; CA2907899A1; RU2015149295A; DK2986821T3; CA2907899C; PL2986821T3; TW201510372A; CN105121784A; KR20160002963A; RU2641409C2; AU2013387156A1; ES2854989T3

Abstract

The present disclosure relates to a vane-type rotary vacuum pump comprising a drive motor (1, 17) interacting with a vane-pump vacuum chamber (2), in which pump all the pump surfaces that are visible from the top are arranged in such a way that they have no elements likely to retain liquids or solids. The drive motor (1) may in particular be an air-cooled asynchronous motor or a water-cooled asynchronous motor with a case that, with the cylinder (18), forms a space in which a cooling fluid can circulate.

Description

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Rotary Vane Vacuum Pump

Technical Field of the Invention

The invention concerns a rotary vane vacuum pump having in particular use in the industry in which it is needed to respect certain rules of hygiene both during operation of the pump and when it comes to the cleaning services.

Background of the invention A reference herein to a patent document or other matter which is given as prior art is not to be taken as an admission that that document or matter was known or that the information it contains was part of the common general knowledge as at the priority date of any of the claims.

Rotary vane vacuum pumps have existed for a long time. In such pumps, the rotor is equipped with a plurality of blades (called "vanes") which slide radially and which ensure transfer of the air pumped. 15 Described in the European patent application published under the number EP 0 166 807 is an example of such a pump. As can be seen in particular in Figure 1 of this document, a "conventional" vane pump is provided at a number of places on its exterior surface with blades which can form zones of retention of liquids or of solids or prevent natural flow. This renders this type 20 of pump not very suitable or even completely unsuitable for a certain number of applications.

In fact, liquids or solids can be deposited and remain stagnant in said zones of retention on the surface of the pump and thus result in development of pathogenic organisms (molds, bacteria, etc.) which bring about risk of contamination.

The document WO2012/076204 of the applicant describes moreover a pump which is not anymore a lubricated rotary vane vacuum pump, but a dry screw pump devoid of any oil. There, the pumping rotors are located in a cylinder exhibiting a smooth external casing, but in this ways lacks any cooling vanes unlike the pump presented in the document EP0166807 cited above.

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Summary of Invention

It is desirable to provide a rotary vane vacuum pump not having the mentioned drawbacks and which is in particular able to be used in environments subject to strict standards of hygiene. 5 The present invention provides a rotary vane vacuum pump, comprising a drive motor co-operating with a chamber for vacuum vane pumping, wherein all the surfaces situated on the upper half of the pump are set up in such a way that they are devoid of elements susceptible to retaining liquids or solids, and wherein either: 10 - the pump is, at least on one part, provided with removable means of protection devoid of surfaces or cavities susceptible to retaining liquids or solids, or - the said drive motor comprises a double casing with an external part formed by a cylinder and is a water cooled asynchronous motor having a 15 housing forming with the cylinder a space in which a cooling liquid can flow.

The pump of the present invention can, at least on one part, be provided with means of protection without surfaces or cavities susceptible to retention of liquids or solids.

Such a pump has moreover the advantage of being easy to clean. It 20 is thus suitable for all uses in industries in which it is necessary to respect certain rules of hygiene.

Brief Description of Drawings

Other features and advantages of the invention will now be described in detail in the following description which is given with reference to the attached 25 figures, representing schematically: - Figure 1: a rotary vane vacuum pump according to the prior art of the invention; - Figure 2: the pump according to Figure 1, shown in accordance with a first embodiment of the invention; - Figures 3, 4 and 5: views in perspective of front, back and of the front after pivoting in clockwise direction, of a pump according to a second embodiment of the invention;

r- ο (N - Figures 6, 7 and 8: views corresponding respectively to those of Figures 3, 4 and 5, of the pump according to the second embodiment, equipped with an oil mist separator.

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Detailed Description of the Invention

As has already been mentioned, the rotary vane vacuum pump according to the invention is characterized in that all its surfaces visible from 10 above are set up in such a way that they are devoid of elements susceptible to retaining liquids or solids. Such surfaces, which are necessarily exterior, can be formed by cooling vanes, and they are situated on the upper half of the vacuum pump, given that the surfaces situated on the lower half of the vacuum pump are not able to retain, owing to gravity, a liquid or a solid. At this place, it seems 15 important to specify that the adjectives "upper" and "lower" used in this text (and those in the description as well as the claims) refer to the normal position of the pump when it is operating or is ready to operate.

To achieve upper surfaces devoid of the elements susceptible to retaining liquids or solids, it is in particular possible to design the upper part of 20 the surfaces in a smooth way. This can be done during production of the parts constituting the pump, thus for example during the machining of the outer walls of the pumping chamber. 25

Alternatively, the pump can also be provided, at least on one part, with means of protection of the upper surface. These means of protection must likewise be devoid of cavities, for example grooves, situated on the upper half of the vacuum pump and inside of which liquids or solids can stagnate. O (N +-> o o

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First Embodiment

For understanding of a first embodiment of the invention, one can begin by referring to Figure 1 representing a rotary vane vacuum pump according to the prior art.

This pump includes in particular a drive motor, for instance an aircooled asynchronous motor. It is well understood that it would be possible to use another type of motor, including a water-cooled motor, according to the construction design. This motor is coupled to a pumping chamber 2, with the aim to drive the rotor of the latter in rotation, so that the pump can fulfill its pumping function. An intermediate cylinder V2 connects the drive motor to the pumping chamber 2, and it normally contains the elements of connection between the drive motor and the pumping chamber 2.

This pumping chamber 2 is known per se; it generally comprises a rotor which is accommodated in a cylindrical bore and which bears the vanes.

The pumping chamber 2 can be fed with oil, i.e. in that case a system of circulation of oil for lubrication is provided, to ensure the tightness and to permit heat exchange. 10

This oil is separated from gases pumped in an oil mist separator (not represented in the figure), in such a way that the air exiting through the outlet 3 can be cleaned from oil which it contains before being recirculated into the atmosphere.

The pumping chamber 2 is likewise connected to a heat exchanger V1 with an integrated ventilator (not shown) which serves to cool the pumping chamber 2 which reheats during the operation of the pump. 15 The drive motor 1 and the pumping chamber 2 are preferably con nected in removable way, which allows the one or the other to be replaced in the case of failure.

As seen clearly on the Figure 1, the pumping chamber 2 and the drive motor 1 comprise on their circumferences cooling vanes 5. These are in 20 principle those vanes which make this pump according to the prior art not suitable for use in a field requiring respect of certain rules of hygiene and an easy cleaning on site because, as has been explained in the preceding, the vanes can retain liquids or solids.

This is why, according to the invention, of which the first embodiment 25 can be seen by referring to Figure 2, it is foreseen that all the upper surfaces of the pump, thus all the surfaces visible from above, are set up in such a way that they are devoid of elements susceptible to retaining liquids or solids. As can be seen from analysis of Figure 2, it is possible to obtain such smooth surfaces either by forming them in such a manner that they do not comprise elements susceptible to retaining liquids or solids, or by providing means of protection, themselves devoid of surfaces or cavities susceptible to retaining liquids or solids. 5 Seen in Figure 2 is that the upper surface of one part of the pump (in particular the part of the pumping chamber 2) comprises smooth surfaces only. These surfaces thus do not comprise any elements susceptible to retention of liquids or solids so as to allow a natural flow of any liquid or natural slide of any solid that could fall on the pump. Also, Figure 2 shows at the same time the 10 other possibility for achieving the distinctive feature of this invention, i.e. means of protection 6 which are similar to a covering cap, that is to say they have substantially the shape of a half cylinder covering in this case the upper part of the drive motor 1. Of course, it is well understood that a pump could likewise be achieved in the spirit of the present invention wherein the means of protection 6 15 could be positioned in another part of the pump, for example on the pumping chamber 2. 20

By "upper part", referred to here is, as in the foregoing, the case where the pump according to the present invention is disposed horizontally, i.e. when the rotational axis of the drive motor 1 and the rotational axis of the rotor of the pumping chamber 2, which are generally the same, are parallel to the ground, the supports 13 and 14 of the pump resting then normally on the ground (or a support parallel to the ground).

Use above of the adverb "substantially" means that the half cylinder 6 has a shape which is of course adapted to the drive motor 1, for example 25 having a cutout allowing the electrical casing 7 to protrude.

As follows from the Figure 2, the half cylinder 6 covers only the upper vanes 5 of the drive motor, the lower vanes 16 appearing then in the lower part of the drive motor 1.

Preferably, the half cylinder 6 is removable, which has the advantage that it is easily possible to gain access to the drive motor 1 in the case of checking and thorough cleaning.

It is likewise preferable to provide that at least certain and ideally all 5 the upper surfaces of the drive motor 1 and/or of the pumping chamber 2, i.e. those which are visible from above, be inclined downward in such a fashion as to allow the elimination, by flow of the liquids, or by sliding of the solids, during the cleaning when these liquids or solids are present on these surfaces.

As examples of upper surfaces, cited can be those designated in 10 Figure 2 by the reference numerals 8,9,10 and 11 for the pumping chamber 2 and by the reference numerals 12 and 15 for the drive motor 1.

The inclination of the surfaces concerned is preferably at least 5 degrees with respect to the ground, when the supports 13 and 14 rest on the ground. 15 Preferably, it is likewise provided that the oil mist separator compris es a block support common to the filter and to the heat exchanger for the oil which makes it compact, accessible and easily cleanable.

Second Embodiment 20 25 A second embodiment of the invention is shown in Figures 3 to 7.

As can be seen in these figures, the rotary vane vacuum pump comprises a pumping chamber 2 which can be as that of Figures 1 and 2 and which is connected to a drive motor 17. This has the particularity of comprising a double casing having an outer part formed by a cylinder 18, seen in Figure 3, all of which or more or less all of which is of smooth outer side. The inner part of this double casing, which is in fact the housing of the motor not visible in Figure 3, contains, in a known way, the usual components of a rotary vane vacuum pump motor, which can be an asynchronous motor.

Preferably, the outer surface of the cylinder 18 is smooth, in contrast to the first embodiment where the outer surface (cf. Figure 2) is generally provided with cooling vanes 16.

The cylinder 18 is spaced apart from the housing (smooth or not) in 5 such a way as to form a space in which a coolant such as a liquid, in particular water, is able to circulate, by entering and exiting through the orifices 19 and 20.

The advantage of water cooling is that it permits the removal of the heat generated by the drive motor 17, without having to resort to vanes 16 (of 10 Figure 2), whose surface allows exchange of the heat with the air.

Preferably the cylinder 18 is blind, i.e. closed at its free end, which facilitates the cleaning of the pump.

Generally, in this embodiment, the cylinder 18 is not removable because it is fixed to the housing of the drive motor 17. However, it would also be 15 possible to foresee a special embodiment of the present invention in which the cylinder 18 is also removable.

As in the first embodiment of the invention, it is advantageous to provide the inclination of certain and preferably the entire upper surfaces such as the surfaces 8, 9, 10, 11, 15, 21,22 and 23. 20 Also, it is usual to provide, in the case of use of a lubricated vane pumping chamber 2, an oil mist separator as that visible in Figures 6, 7 and 8. Preferably this separator comprises a block support common to the filter and to the heat exchanger for the oil 25, which makes it compact, accessible and easily cleanable. 25 The description which has just been given is that of a plurality of em bodiments of the device according to the invention, not limiting however the scope of the invention which is primarily defined by the claims. Ο (N +-> Ο ο Ό Γ ΟΟ m m

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One skilled in the art will understand the possibilities of development, of modifications and of applications of the pump according to the present invention, and in particular in other fields in which it is important to respect increased levels of hygiene.

Throughout the description and claims of the specification, the word "comprise" and variations of the word, such as "comprising" and "comprises", is not intended to exclude other additives, components, integers or steps.

Claims

The claims defining the invention are as follows:

1. Rotary vane vacuum pump, comprising a drive motor co-operating with a chamber for vacuum vane pumping, wherein all the surfaces situated on the upper half of the pump are set up in such a way that they are devoid of elements susceptible to retaining liquids or solids, and wherein either: - the pump is, at least on one part, provided with removable means of protection devoid of surfaces or cavities susceptible to retaining liquids or solids, or - the said drive motor comprises a double casing with an external part formed by a cylinder and is a water cooled asynchronous motor having a housing forming with the cylinder a space in which a cooling liquid can flow.
2. Rotary vane vacuum pump according to claim 1, wherein the means of protection have substantially the shape of a half cylinder covering at least one upper part of the pump.
3. Rotary vane vacuum pump according to any one of the claims 1 or 2, wherein the means of protection are positioned solely at the level of the drive motor.
4. Rotary vane vacuum pump according to any one of the preceding claims, wherein the drive motor is an air-cooled asynchronous motor.
5. Rotary vane vacuum pump according to any one of claims 1 to 4, wherein said cylinder is a blind cylinder.
6. Rotary vane vacuum pump according to any one of the preceding claims, wherein, when the axis of rotation of the drive motor and that of the rotor of the pumping chamber are parallel to the ground, at least certain of the upper surfaces of the drive motor and/or of the pumping chamber are inclined downwardly.
7. Rotary vane vacuum pump according to any one of the preceding claims, wherein the vanes are oil-lubricated.
8. Rotary vane vacuum pump according to claim 7, wherein the pumping chamber is connected to an oil mist separator.
9. Rotary vane vacuum pump according to claim 8, wherein the oil mist separator includes a block support common to the filter and to the thermal exchanger for the oil.