Ejector-type vacuum pump

Abstract

An ejector-type vacuum pump is described, said ejector-type vacuum pump being configured to accommodate two or more ejector cells, each of which two or more ejector cells is separately accessible and replaceable from the outside of the ejector-type vacuum pump. An ejector-cell can be replaced with a passive ejector-cell replacement insert, thereby allowing for facilitated modulation of the suction power. Also, modulation of the suction power can easily be accomplished by replacing an ejector cell with another ejector cell having different nozzle characteristics.

Description

FIELD OF THE INVENTION

[0001] The present invention relates to a vacuum generator, and more particularly to an ejector-type vacuum pump having one or more ejector cells, each of which one or more ejector cells is separately accessible and replaceable from the outside of the ejector-type vacuum pump. A separate ejector-cell of the inventive vacuum pump can be replaced with a passive ejector-cell replacement insert, thereby allowing for facilitated modulation of the suction power of the inventive vacuum pump.BACKGROUND ART

[0002] Vacuum generators are known in the art. The vacuum generators referred to herein are fed with a flow of pressurized air which produces a reduced pressure in the vacuum generator. Such vacuum generator comprises one or more ejector cells. An ejector cell may also be referred to as a venturi cell. The one or more ejector cells are typically multi-staged. In each stage vacuum can be generated. For each stage in a vacuum generator a suction chamber is provided. A vacuum generator comprising one or more multi-stage ejector cells may be referred to as a multi-stage ejector-type vacuum pump. In the case of a multi-stage ejector-type vacuum pump having two or more, typically two, three or four ejector cells, the ejector cells may be connected in parallel, so that, for each stage, there is a suction chamber shared by the ejector cells. A multi-stage ejector-type vacuum pump wherein the ejector cells are formed internally in the pump body is known e.g. from WO 1999 / 049216.

[0003] WO 2022 / 269363 discloses, in Fig. 7, a 2-staged, and, in Fig. 2, a 3-staged ejector-type vacuum pump having four venturi cells. The four venturi cells are arranged in a cluster 40, which cluster can be inserted in one piece into the vacuum generator 1. Thereby, the number of seals required can be kept low. According to WO 2022 / 269363, a large number of seals, as required when a venturi cell has a cylindrical body allowing easy insertion into a vacuum pump body, promotes the risk of leaks. Also, according to WO 2022 / 269363, the use of individual venturi cells, as used in EP 2827004 and EP 1064464, would require the assembly and disassembly of each of the cells inserted in the pump body, which increases the time of manufacture of the pump, and the time of its maintenance. The cluster 40 is inserted into a housing 10 and secured therein by the rear face 10d of the housing. The flow rates sucked in and consumed by the vacuum generator disclosed in WO 2022 / 269363 can be reduced by modulating the number of venturi cells. For this purpose, once the cluster has been removed from the housing, any one of the four three-staged venturi cells can be deactivated by insertion of four plugs 50, 51, 52, 53 into the desired venturi cell. Such modulation moreover requires removal of the cluster in order for the cluster to be accessible for plugging of the desired venturi cell therein.

[0004] It would be desirable to be able to facilitate modulation of the suction power of a vacuum generator.SUMMARY OF THE INVENTION

[0005] According to the present invention, for an ejector-type vacuum pump having one or more ejector cells, such as disclosed in WO 2022 / 269363, this object has been accomplished by making each one said one or more ejector cells separately accessible and replaceable from the outside of the ejector-type vacuum pump.

[0006] Accordingly, in one aspect the invention relates to an ejector-type vacuum pump 1 configured to be able to accommodate therein two or more removable ejector cells, the ejector-type vacuum pump comprising: a pump body 10; a housing 20 configured to accommodate the pump body 10; two or more removable ejector cells 30; an inlet 40 provided in the housing configured to receive pressurized air; a suction opening 50 provided in the housing; seals 70 configured to air-tightly seal the two or more ejector cells 30 to the pump body 10, said two or more ejector cells 30 being removable from the pump body 10 and configured to be secured in an operational position within the housing 20 in an ejector cell seat 85 formed in the pump body, wherein the two or more ejector cells 30 are separate, the pump body 10 exhibits two or more separate ejector cell seats 85 formed in the pump body configured to accommodate the two or more ejector cells, wherein the number of separate cell seats corresponds to the number of the separate ejector cells, wherein, in each one of which separate ejector cell seats 85 a separate ejector cells 30 is fitted, and, wherein the housing 20, in a rear wall 25 thereof, has a separate opening 80 for each one of said one or two or more ejector cells 30 configured to allow for insertion and removal of a separate ejector cell 30 through said separate opening 80.

[0007] The present invention allows for readily access of an ejector cell 30 from the outside of the vacuum pump 1 without the vacuum pump having to be opened. A separate ejector cell 30 of the invention can be removed from its position in the vacuum pump for maintenance or for replacement thereof. Thereby, exposure of the interior of the pump, and also of any further ejector cells 30 is minimised, and hence, the risk of fouling or contamination is reduced.

[0008] According to the invention, a separate ejector cell 30 of the two or more separate ejector-cells of the inventive ejector-type vacuum pump 1 can be replaced with a separate ejector-cell replacement insert 35, configured to correspond to a fully air-tightly plugged ejector cell 30, which is inserted into one of the two or more separate openings 80.

[0009] Accordingly, in another aspect the invention relates to an ejector-type vacuum pump 1 configured to be able to accommodate therein two or more ejector cells, the ejector-type vacuum pump comprising: a pump body 10; a housing 20 configured to accommodate the pump body 10; one or more ejector cells 30; an inlet 40 provided in the housing configured to receive pressurized air; a suction opening 50 provided in the housing; seals 70 configured to air-tightly seal the one or more ejector cells 30 to the pump body 10, said one or more ejector cells 30 being removable from the pump body 10 and configured to be secured in an operational position within the housing 20 in an ejector cell seat 85 formed in the pump body, wherein the ejector-type vacuum pump 1 additionally comprises one or more removable ejector-cell replacement inserts 35, each of which one or more removable ejector-cell replacement inserts 35 is configured to correspond to a fully air-tightly plugged ejector cell 30, in that each one of said one or more removable ejector cells 30 and said one or more removable ejector-cell replacement inserts 35 is separate, in that the pump body 10 exhibits two or more separate ejector cell seats 85 formed in the pump body configured to be able to accommodate the one or more separate ejector cells and the one or more ejector-cell replacement inserts 35, wherein the number of separate ejector cell seats 85 corresponds to the total number of separate removable ejector cells 30 and separate removable ejector-cell replacement inserts 35, wherein, in each one of which separate ejector cell seat 85 a separate ejector cell 30 or a separate ejector-cell replacement insert 35 is fitted, wherein the seals 70 are additionally configured to air-tightly seal the one or more separate ejector-cell replacement inserts 35 to the pump body 10, said one or more separate removable ejector-cell replacement inserts 35 being removable from the pump body 10 and configured to be secured within the housing 20 and, in that the housing 20, in a rear wall 25 thereof, has a separate opening 80 for each one of said one or one or more ejector cells 30 and for each one of said one or more ejector-cell replacement inserts 35 configured to allow for insertion and removal of a separate ejector cell 30, and a separate ejector-replacement 35, respectively, through said separate opening 80.

[0010] By replacement of a separate ejector cell 30 with a separate ejector-cell replacement insert 35, the suction power of the vacuum pump 1 will be reduced. The invention thus allows for modulating the suction power performance of the vacuum pump by regulating the number of active or operatable ejector cells in the vacuum pump. The higher the number of ejector-cells 30 the vacuum pump is configured to accommodate, the larger the degree of modulation available by replacement of one or more individual ejector-cells with a corresponding number of individual ejector-cell replacement inserts 35.

[0011] The seals 70 are preferably recessed into the inventive individual ejector-cell replacement insert 35, so that also the associated seals will be removed from the pump body along with the ejector-cell replacement insert upon removal of the individual ejector-cell replacement insert from the pump body. This way the seals can easily be inspected, cleaned, and replaced, e.g. due to wear, when needed.

[0012] The annular seals 70 are preferably recessed into the inventive separate ejector cell 30, so that also the associated seals will be removed from the pump body along with the separate ejector cell upon removal of the individual separate ejector cell from the pump body. This way the seals can easily be inspected, cleaned, and replaced, e.g. due to wear, when needed. According to the present invention, the separate ejector cell 30 does not include a valve, such as e.g. a non-return valve.

[0013] Preferably, the seals 70 are annular. The annular form is believed to facilitate effective sealing, both for an ejector cell 30 and for an ejector-cell replacement insert 35, as compared to other geometries.

[0014] The inventive individual ejector-cell replacement insert 35 is configured to correspond to a fully air-tightly plugged individual ejector cell 30, which is inserted into one or more of the separate openings 80. The seals 70 are configured to air-tightly seal the ejector-cell replacement insert 35 to the pump body 10.

[0015] By replacement of a separate ejector-cell replacement insert 35 with a separate ejector cell 30, the suction power of the vacuum pump 1 will be reduced. The invention thus allows for modulating the suction power performance of the vacuum pump by regulating the number of active or operatable ejector cells in the vacuum pump. The higher the number of ejector-cells the vacuum pump is configured to accommodate, the larger the degree of modulation available by replacement of one or more individual ejector-cells with a corresponding number of separate ejector-cell replacement inserts.

[0016] As opposed to the vacuum generator of WO 2022 / 269363, an individual ejector cell 30 of the inventive vacuum pump 1 can be removed without opening the vacuum pump, without exposing the interior of the pump and / or other ejector cells, thereby risking fouling of the exposed parts, and, also as opposed to the vacuum generator of WO 2022 / 269363, plugging of an individual ejector cell 30 merely requires replacement, from the outside of the pump, of the individual ejector cell 30 with an individual ejector-cell replacement insert 35. The removed ejector cell 30 itself does not have to be plugged or modified in any way, but can safely be stored away until needed again, ready for use as is.

[0017] The enhanced modulation of pump performance according to the invention is believed to assist in reducing energy consumption and costs.

[0018] Further embodiments and advantages of the invention will be apparent from the following detailed description and appended claims.BRIEF DESCRIPTION OF THE ATTACHED DRAWINGS

[0019] Figure 1 shows an exploded perspective view of a multi-stage embodiment of the ejector-type vacuum pump 1 of the invention comprising three stages and having three ejector-cells 30, one of which has been removed, leaving open an opening 80 in the vacuum pump housing 20. Figure 2 shows a view of a cross-section in the plane A-A as indicated in FIG. 1, wherein the three stages of vacuum pump 1 and the ejector-cell seats (85a-85d), in which seats the removed ejector cell is to be accommodated, can be seen. Figure 3 shows a side view of the removed ejector-cell 30 in FIG. 1. Figure 4 shows a more detailed cross-sectional view of the ejector-cell 30 in FIG. 3 along the line B-B, wherein the three stages of ejector-cell 30 can be seen. Figure 5 shows a side view of an embodiment of an ejector-cell replacement insert 35, configured to replace the removed ejector-cell 30 shown in FIGS. 1-4. Figure 6 shows a cross-sectional view of the ejector-cell replacement insert 35 in FIG. 5 along the line C-C. DETAILED DESCRIPTION OF THE INVENTION

[0020] The inventive vacuum pump 1 is configured to be able to accommodate two or more ejector cells 30. Accordingly, in an embodiment with only two ejector cell seats 85, each one of the two seats can be fitted with an individual ejector cell 30, one of which could be replaced with an ejector-cell replacement insert 35, so that the inventive vacuum pump will comprise at least one ejector cell 30 also in a situation wherein one ejector cell has been replaced with an ejector-cell replacement insert 35. Typically, the inventive vacuum pump 1 is configured to accommodate three or more ejector cells, such as 3, 4, 5 or 6 separate ejector cells. The ejector cells are arranged in parallel, and can e.g. be stacked in layers, such as e.g. divided into 2, 3 or 4 layers each having e.g. 2 to 4 ejector cells, or arranged so as to form a cylinder.

[0021] The number of stages of an inventive multi-stage ejector-type vacuum pump can typically be 2, 3 or 4. In the case of 2, 3, or 4 stages, for improved maintained vacuum level after discontinued flow of pressurized air, a check-valve 60 (not shown) common to all stages of the inventive multi-stage vacuum pump may be provided connected to the suction opening 50. For an enhanced vacuum level and for energy saving purposes, it is preferred that a separate check-valve 60 be provided for each one of all stages, e.g. such as shown in FIGS. 1 and 2. When present, the check-valve of a certain stage is preferably common to all injectors of that stage, e.g. such as shown in FIGS. 1 and 2. When present, a check-valve 60 (not shown) may be common to two or more stages of the inventive multi-stage vacuum pump 1. Preferably, however, as already pointed out above, and, as shown in FIGS. 1 and 2, a separate a separate check-valve 60 is provided for each one of the stages. When two or more stages are included in the inventive ejector-type vacuum pump 1, a common vacuum chamber 47 is provided, such as shown in FIGS. 1 and 2, into which chamber each one of the stages opens. The common vacuum chamber 47 is configured to fluidly connect all stages of an inventive multi-stage vacuum pump embodiment 1 with the suction opening 50.

[0022] A check-valve 60 can e.g. simply be embodied as a flap valve, such as shown in FIG. 1. A flap valve 60 can suitably be made from a flexible material, such as an elastomer. When a separate check-valve 60 is provided for each one of the stages, the check-valves can be attached to a valve-opening plate 65 having openings 67 configured to fluidly connect the stages of the inventive multi-stage ejector-type vacuum pump 1 with the common vacuum chamber 47, such as indicated in FIGS. 1 and 2.

[0023] An exhaust chamber 45 is formed in the inventive pump from which exhaust air is exited through exhaust opening 55. The exhaust chamber 45 is configured to receive exhaust air being expelled from the ejector cells 30 from the last stage of the ejector pump. Each ejector cell 30 is provided with one or more exhaust openings 77, which open into exhaust chamber 45.

[0024] The ejector-cell replacement insert 35 has a form similar to that of an ejector-cell 30. Since the function of the ejector-cell replacement insert 35 is plugging an ejector-cell position in the vacuum pump body 10, it can be made simple and light-weight, such as in a suitable plastic material. Similar seals 70 are used both for the ejector-cell replacement insert 35 and for the ejector-cell 30. In a preferred embodiment the inventive ejector-cell replacement insert 35 is integrally formed in one piece, with exception for the seals 70, as shown in FIG. 4.

[0025] The ejector-cell 30 and ejector-cell replacement insert 35, respectively, preferably comprise a locking portion 90 configured to be releasably secured to the housing 20 from the outside in the separate opening 80. The locking portion 90 is preferably attached to the ejector-cell 30 and ejector-cell replacement insert 35, respectively, so as to allow for the ejector-cell 30 and ejector-cell replacement insert 35 to be pulled out from the vacuum pump by pulling the locking portion 90. The type of locking of locking portion 90 to the housing 20 is not critical and be a twist-lock fitting, e.g. such as shown in the FIGS., or a quick release coupling, such as e.g. of bayonet-type (not shown).

[0026] An ejector-cell 30 and an ejector-cell replacement insert 35 preferably comprise similar locking portions 90.

[0027] The locking portion 90 could be formed as a separate member, i.e. as locking member 90 (not shown). The attachment of a separate locking member 90 to an ejector-cell 30 or to an ejector-cell replacement insert 35, can suitably be a snap fitting (not shown).

[0028] In one embodiment, locking member 90 is rotatably attached to the ejector-cell 30 (not shown) and to the ejector-cell replacement insert 35 (not shown), such that when the locking member 90 is a twist lock member, the locking member can be twisted without the ejector-cell or the ejector-cell replacement insert being twisted.

[0029] When the locking portion 90 has been unlocked from the opening 80, the ejector-cell or the ejector-cell replacement insert can be pulled out from the vacuum pump by pulling the locking portion which is attached to the ejector-cell 30 or the ejector-cell replacement insert 35.

[0030] For improved structural integrity and ease of manufacture of an inventive ejector-cell replacement insert 35, it is preferred to make the locking portion 90 integral with the ejector-cell replacement insert 35 as shown in FIGS. 5 and 6. For enhanced ease of manufacture, and for simplified marking of an ejector cell 30, e.g. colour marking corresponding to the performance of the ejector cell, it is presently preferred for the ejector-cell 30 that the locking portion 90 is formed as a separate locking member 90, preferably configured to be snap fitted on to the ejector cell 30. For improved robustness of an inventive ejector cell 30 having a separate locking member 90 attached thereto, it is preferred that the locking member in its attached position to the ejector cell 30 is prevented from rotation, e.g. by one or more peripheral protrusions (not shown) formed on the rear part of the ejector cell 30, and one or more corresponding openings or recesses (not shown) formed in the locking member 90 into which opening or recess a peripheral protrusion fits.

[0031] Each ejector cell comprises in its front-end a first nozzle 75 configured to receive pressurized air from inlet 40. A given first nozzle 75 can be configured to provide a certain maximum performance. Accordingly, different first nozzles can be used to provide different maximum performance to different ejector cells. Hence, according to the invention modulation of the suction power can easily be accomplished by replacing an ejector cell with another ejector cell having different nozzle characteristics. In preferred embodiments, the first nozzle 75 of an ejector cell 30 is configured to be replaceably attached to the ejector cell, such as by means of a snap fitting.

[0032] While there will be a nozzle provided for each stage of the inventive ejector pump, all of which could be configured differently in different ejector cells, it is presently considered more efficient and hence preferred to provide the variability of nozzle characteristics by varying the first nozzle 75 only. Accordingly, in a preferred embodiment, the first nozzle is configured to be attached to the ejector cell 30. In such embodiments, such as shown in FIG. 3, the number of seals 70 on an ejector cell equals the number of stages + 1, i.e. one for each one of the four portions a, b, c, and d forming cell seat 85. Accordingly, the ejector-cell shown 30 in FIGS. 3 and 4, having three nozzles, which is configured to be used in a three-staged ejector pump, consequently exhibits 4 seals 70. Similarly, an ejector-cell replacement insert 35 such as shown in FIGS. 5 and 6, which is configured to be used in a three-staged ejector pump, consequently also exhibits 4 seals 70.

[0033] For each nozzle of an ejector cell 30, one or more inlet openings 76 are provided on the ejector cell aft of the nozzle.

[0034] The performance of a given ejector cell is preferably configured to be recognizable from the outside, e.g. from a colour code or a marking provided on the outer surface 100 of the locking portion 90, which portion for this purpose preferably takes the form of a separate locking member 90. Similarly, an ejector-cell replacement insert 35 is preferably also configured to be recognizable from the outside.

[0035] The cell seats 85 preferably exhibit a stopping means configured to prevent an ejector cell or an injector-cell replacement insert from being further inserted, beyond the stopping means, into the pump body. In a preferred embodiment, the front-end portion 85a of each cell seat 85 exhibits a reduced diameter (not shown) configured to prevent the first nozzle 75 of an ejector cell 30 from being further introduced into the pump body. As will be understood from the present disclosure, the stopping means must be configured to allow for pressurized air to enter into the first nozzle.

[0036] In preferred embodiments, a tool coupling portion is provided in the outer surface 100 of the locking portion 90. For simplified locking, unlocking and replacement of an ejector cell or ejector-cell replacement insert, the tool coupling portion can e.g. be embodied as a recess in the surface 100 configured to couple with a tool, e.g. a slot 110 configured to couple which e.g. a coin or screw driver, e.g. as shown in FIGS. 1, 2, 4, and 6.

[0037] For a desired quick response time of the inventive ejector pump 1, the inner volume of the pump should be kept small.LIST OF REFERENCE NUMERALS USED

[0038] 1ejector-type vacuum pump 10pump body 20vacuum pump housing 25rear wall of housing 20 26outer surface of the rear wall 25 30removable ejector cell 35ejector-cell replacement insert 40inlet for pressurized air 45exhaust chamber 47common vacuum chamber 50suction opening 55exhaust opening 60check-valve 65valve opening plate 67valve opening 70seals 75first nozzle of ejector cell 76ejector-cell inlet opening 77ejector-cell exhaust opening 80separate ejector-cell opening 85separate ejector-cell seat 90locking portion 100outer surface of locking portion 90 110tool coupling portion in outer surface of locking portion A-Asection through vacuum pump and separate removed ejector cell B-Bsection through a separate ejector cell C-Csection through a separate ejector-cell replacement insert

Claims

1. An ejector-type vacuum pump (1) configured to be able to accommodate therein two or more ejector cells, the ejector-type vacuum pump comprising: a pump body (10); a housing (20) configured to accommodate the pump body (10); two or more ejector cells (30); an inlet (40) provided in the housing configured to receive pressurized air; a suction opening (50) provided in the housing; seals (70), configured to air-tightly seal the two or more ejector cells (30) to the pump body (10), said two or more ejector cells (30) being removable from the pump body (10) and configured to be secured in an operational position within the housing (20) in an ejector cell seat (85) formed in the pump body, characterized in that the two or more removable ejector cells (30) are separate, the pump body (10) exhibits two or more separate ejector cell seats (85) formed in the pump body configured to accommodate the two or more separate removable ejector cells, wherein the number of separate cell seats (85) corresponds to the number of separate removable ejector cells (30), wherein, in each one of said separate ejector cell seats (85) a separate removable ejector cell (30) is fitted, and, in that the housing (20), in a rear wall (25) thereof, has a separate opening (80) for each one of said two or more separate removable ejector cells (30) configured to allow for insertion and removal of a separate removable ejector cell (30) through said separate opening (80).

2. The ejector-type vacuum pump (1) of claim 1, wherein each one of the two or more ejector cells (30) comprises a locking portion (90) configured to be releasably secured to the housing (20) from the outside in said separate opening (80).

3. The ejector-type vacuum pump (1) of claim 2, wherein the locking portion (90) is formed as a separate member axially attached to the respective ejector cell (30).

4. The ejector-type vacuum pump (1) of claim 2 or 3, wherein, in an outer surface (100) of the locking portion (90), a tool coupling portion (110) is formed.

5. The ejector-type vacuum pump (1) of any one of the previous claims, wherein a nominal maximum performance of each ejector cell (30) is recognizable from the outside, e.g. from the outer surface (100) of the locking portion (90) having a certain colour or a marking provided on the outer surface (100) of the locking portion (90) corresponding to a certain nominal maximum performance of the ejector cell (30).

6. The ejector-type vacuum pump (1) of any one of the previous claims, wherein the seals (70) are annular and are recessed into the two or more ejector cells (30).

7. An ejector-type vacuum pump (1) configured to be able to accommodate therein two or more ejector cells, the ejector-type vacuum pump comprising: a pump body (10); a housing (20) configured to accommodate the pump body (10); one or more ejector cells (30); an inlet (40) provided in the housing configured to receive pressurized air; a suction opening (50) provided in the housing; seals (70) configured to air-tightly seal the one or more ejector cells (30) to the pump body (10), said one or more ejector cells (30) being removable from the pump body (10) and configured to be secured in an operational position within the housing (20) in an ejector cell seat (85) formed in the pump body, characterized in additionally comprising one or more removable ejector-cell replacement inserts (35), each of which one or more removable ejector-cell replacement inserts (35) is configured to correspond to a fully air-tightly plugged ejector cell (30), in that each one of said one or more removable ejector cells (30) and said one or more removable ejector-cell replacement inserts (35) is separate, in that the pump body (10) exhibits two or more separate ejector cell seats (85) formed in the pump body configured to be able to accommodate the one or more separate ejector cells and the one or more ejector-cell replacement inserts (35), wherein the number of separate ejector cell seats (85) corresponds to the total number of separate removable ejector cells (30) and separate removable ejector-cell replacement inserts (35), wherein, in each one of which separate ejector cell seat (85) a separate ejector cell (30) or a separate ejector-cell replacement insert (35) is fitted, wherein the seals (70) are additionally configured to air-tightly seal the one or more separate ejector-cell replacement inserts (35) to the pump body (10), said one or more separate removable ejector-cell replacement inserts (35) being removable from the pump body (10) and configured to be secured within the housing (20) and, in that the housing (20), in a rear wall (25) thereof, has a separate opening (80) for each one of said one or one or more ejector cells (30) and for each one of said one or more ejector-cell replacement inserts (35) configured to allow for insertion and removal of a separate ejector cell (30), and a separate ejector-replacement (35), respectively, through said separate opening (80).

8. The ejector-type vacuum pump (1) of claim 7, wherein each one of the one or more ejector-cell replacement inserts (35), comprises a locking portion (90) configured to be releasably secured to the housing (20) from the outside in said separate opening (80).

9. The ejector-type vacuum pump (1) of claim 8, wherein, in an outer surface (100) of the locking portion (90), a tool coupling portion (110) is formed.

10. The ejector-type vacuum pump (1) of any one of claims 7-9, wherein an ejector-cell replacement insert (35) is configured to be recognizable from the outside, e.g. from having a certain colour or a marking provided on the outer surface (100) of the locking portion (90).

11. The ejector-type vacuum pump (1) of any one of the previous claims, wherein the ejector-type vacuum pump (1) is a multi-stage ejector-type vacuum pump, preferably comprising 2, 3, or 4 stages, each one of which stages is fluidly connected to the suction opening (50) via a common vacuum chamber (47).

12. The multi-stage ejector-type vacuum pump (1) of claim 11, comprising a check-calve (60) common to one or more of the stages configured to prevent a flow of air from exiting from the common vacuum chamber (47) into the suction opening (50).

13. The multi-stage ejector-type vacuum pump (1) of claim 11 or 12, comprising a separate respective common check-calve (60) for each one of the one or more stages configured to prevent a flow of air from exiting from a stage into the common vacuum chamber (47) through a valve opening (67).

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