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 an ejector-cell replacement insert, thereby allowing for facilitated modulation of the suction power and performance of the ejector-type vacuum pump. Also, modulation of the characteristics of the ejector-type vacuum pump, is described and can easily be accomplished e.g. by replacing an ejector cell with another ejector cell having different characteristics, such as different nozzle characteristics.

Description

[0001] EJECTOR-TYPE VACUUM PUMP

[0002] FIELD OF THE INVENTION

[0003] 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. An ejector cell of the inventive vacuum pump can be replaced with an ejector-cell replacement insert, or with another ejector cell having different characteristics, such as different nozzle characteristics, thereby allowing for facilitated modulation of the characteristics and / or the performance, such as e.g. suction power, of the inventive vacuum pump. The invention also relates to methods of modulating pump characteristics and / or performance of the inventive ejector-type vacuum pump.

[0004] BACKGROUND ART

[0005] 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. A vacuum generator comprising one or more multi-stage ejector cells may be referred to as a multi-stage ejector-type vacuum pump.

[0006] A multi-stage ejector-type vacuum pump, wherein an ejector having two or more nozzles is accommodated in a pump housing, is known e.g. from WO 99 / 49216 Al. According to WO 99 / 49216 Al, the pump housing could be formed for mounting therein two or more of the ejectors disclosed therein operating in parallel.

[0007] 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, such that, for each stage, there is a suction chamber shared by the ejector cells.

[0008] WO 2022 / 269363 Al discloses, in Fig. 7, a 2-staged, and, in Fig. 2, a 3-staged ejectortype 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 Al, 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 Al, 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 lOd of the housing. The flow rates sucked in and consumed by the vacuum generator disclosed in WO 2022 / 269363 Al 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.

[0009] KR 20160027515 A discloses a vacuum ejector pump having a plurality of multi-stage ejectors installed in a single housing. The vacuum ejector pump disclosed therein includes a plurality of vacuum chambers; one vacuum chamber for each multi-stage ejector. The vacuum chambers are arranged so as to communicate with each other. Valves are provided on each stage of each one of the multi-stage ejectors.

[0010] US 2019 / 0054635 Al discloses a vacuum gripper unit comprising a vacuum pump. The pump has a common vacuum chamber, and first and second mounting cylinders. The first cylinder has the vacuum pump inserted and mounted therein, and the second mounting cylinder selectively has the vacuum pump inserted and mounted therein or a release valve inserted and mounted therein.

[0011] It would be desirable to be able to facilitate modulation of the suction power of a vacuum generator.

[0012] SUMMARY OF THE INVENTION

[0013] According to the present invention, for a multi-stage vacuum generator having multistage venturi cells, such as disclosed in WO 2022 / 269363 Al, the above object has been accomplished by making each one of said venturi cells separately accessible and replaceable from the outside of the multi-stage vacuum pump.

[0014] According to the present invention, for an ejector-type vacuum pump having a plurality of multi-stage ejectors, such as disclosed in KR 20160027515 A, the above object has been accomplished by providing in the ejector-type vacuum pump a number of vacuum chambers, which number is equal to the number stages of the multi-stage ejectors, wherein each one of the vacuum chambers is common to merely one stage of the multi-stage ejectors, which vacuum chamber is configured to accommodate a corresponding vacuum generating stage of each one of the plurality of multi-stage ejectors when inserted into the ejector-type vacuum pump.

[0015] In its most generic embodiment, the inventive ejector-type vacuum pump comprises a pump body configured to be able to accommodate therein two ejector cells. The invention provides for the option of replacing an ejector-cell in the pump body with an ejector-cell replacement insert corresponding to an air-tightly plugged ejector cell. Accordingly, in its most generic embodiment, the inventive ejector-type vacuum pump comprises a first ejector cell inserted in the pump body, and, either a second ejector cell inserted in the pump body, or an ejector-cell replacement insert inserted in the pump body.

[0016] Accordingly, in one 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 therein the pump body 10; a first ejector cell 30 having one or more vacuum generating stages; two or more ejector cell seats 85 formed in the pump body 10, each one of said two or more ejector cell seats 85 being configured to be able to accommodate therein an ejector cell 30, a total number of the ejector cell seats 85 corresponding to a total number of the ejector cells 30 which the pump is configured to be able to accommodate; an inlet 40 provided in the housing 20 configured to receive pressurized air; a suction opening 50 provided in the housing 20; seals 70, configured to air-tightly seal the first ejector cell 30 to the pump body 10, said first ejector cell 30 being removable from the pump body 10 and configured to be secured in an operational position within the housing 20 in a first ejector cell seat 85 of said two or more ejector cell seats 85 formed in the pump body 10, wherein the housing 20, in a rear wall 25 thereof, has a separate opening 80 for each one of said two or more ejector cell seats 85, the separate opening 80 being configured to allow for insertion into the cell seat 85 and removal from the cell seat 85 of an ejector cell 30 through said separate opening 80, wherein the pump body 10 has one or more vacuum chambers 47i, 472, 47s, wherein each one of the one or more vacuum chambers 47i, 472, 47s fluidly communicates with the suction opening 50, the pump body 10 additionally selectively comprises a second ejector-cell 30 having same number of vacuum generating stages as the first ejector-cell 30 in a second ejector cell seat 85 of said two or more ejector cell seats 85 formed in the pump body 10 or a first ejector-cell replacement insert 35 in the second ejector cell seat 85 of said two or more ejector cell seats 85 formed in the pump body 10, wherein each vacuum chamber 47i, 472, 47s is configured to house therein a selected vacuum generating stage of the first ejector cell 30, and of the second ejector cell 30 when present, wherein the seals 70 are additionally configured to air-tightly seal, when present, the second ejector cell 30 to the pump body 10, and, when present, the first ejector-cell replacement insert 35 to the pump body 10, wherein the second ejector cell 30, when present, is removable from the pump body 10 and configured to be secured in an operational position within the housing 20 in the second ejector cell seat 85 of said two or more ejector cell seats 85 formed in the pump body 10, and wherein the first ejector-cell replacement insert 35, when present, is removable from the pump body 10 and configured to be secured within the housing 20 in the second ejector cell seat 85 of said two or more ejector cell seats 85 formed in the pump body 10 in a position air-tightly plugging the second ejector cell seat.

[0017] Accordingly, the above aspect could be divided into embodiments of the inventive ejector-type vacuum pump 1 having two or more ejector cells 30 and no injector-cell replacement insert 35, and embodiments having at least one ejector cell 30 and one or more injector-cell replacement inserts 35, respectively, provided in the latter case that at least one ejector cell 30 is included in the inventive pump 1.

[0018] The first and second ejector cells 30 or the first ejector cell 30 and the first ejector-cell replacement insert 35 of the inventive ejector-type vacuum pump 1 are independently and separately from each other removable from the pump body 10 of the inventive ejector-type vacuum pump 1. Any additional one or more further ejector cells 30 and / or any additional one or more further ejector-cell replacement inserts 35 accommodated in the pump body 10 of the inventive ejector-type vacuum pump 1 are also each and every one independently and separately from each other removable from the pump body 10.

[0019] In each ejector cell seat 85 in the inventive ejector-type vacuum pump 1 in addition to the first and second ejector cell seats 85 of said two or more ejector cell seats 85 formed in the pump body 10 either a removable ejector cell 30 is to be fitted or a removable ejectorcell replacement insert 35 is to be fitted.

[0020] In the inventive ejector-type vacuum pump 1 seals 70 are provided to air-tightly seal any one or more further ejector cells 30 and any one or more further replacement inserts 35.

[0021] 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. An individual 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 present in the pump, is minimised, and hence, the risk of fouling or contamination is reduced.

[0022] According to the invention, an ejector cell 30 of the inventive ejector-type vacuum pump 1 can be replaced with an ejector-cell replacement insert 35, configured to correspond to a fully air-tightly plugged ejector cell 30, which is inserted into a corresponding separate opening 80. For an intended functioning of the pump, the pump must comprise at least one ejector cell 30, and, additionally, each one of the two or more ejector cell seats 85 in the pump must be occupied, either by a removable ejector cell 30, or by a removable ejector-cell replacement insert 35.

[0023] Accordingly, in another aspect the present invention relates to a method of adapting a pump performance of an ejector-type vacuum pump 1, the ejector-type vacuum pump 1 being configured to be able to accommodate therein two or more ejector cells 30, comprising the step of: inserting into the ejector-type vacuum pump 1, from an outside of the ejectortype vacuum pump 1, an ejector-cell replacement 35 exhibiting no ejector performance. By replacement of an individual ejector cell 30 with an individual ejector-cell replacement insert 35, the maximum achievable 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 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.

[0024] 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.

[0025] The annular seals 70 are preferably recessed into the inventive individual ejector cell 30, so that also the associated seals will be removed from the pump body along with the 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.

[0026] According to the present invention, the ejector cell 30 is not required to include a valve, such as e.g. a non-return valve. Preferably, the one or more ejector cells 30 used according to the invention do not include a valve. By not including a valve, the ejector cells 30 can be made smaller in size and will be less sensitive to fouling, and, when inserting a valveless ejector cell 30 into the pump, a valve does not need to be inspected and possibly also cleaned. Instead, a non-return valve can be arranged for the one or more vacuum chambers.

[0027] 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.

[0028] 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 in the ejector cell seat 85.

[0029] As opposed to the vacuum generator of WO 2022 / 269363 Al, an individual ejector cell

[0030] 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 Al, 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.

[0031] The enhanced degree and ease of modulation of pump performance according to the invention is believed to assist in reducing energy consumption and costs.

[0032] The present invention allows for an individual ejector cell of the pump to be quickly and easily be replaced, inserted or removed. Thereby, the inventive ejector-type vacuum pump allows for swift modulation or adaptation of its performance to fit a desired performance.

[0033] With a quick release coupling, such as e.g. of a bayonet-type, the ease of removal and insertion of an ejector cell and an injector cell replacement insert can be further enhanced.

[0034] Also, different ejector cells may exhibit different characteristics in terms of feed pressure, air flow, and obtainable degree of vacuum generated. Accordingly, the performance and / or the characteristics of the inventive ejector-type vacuum pump can be modulated by replacement of one ejector cell having a certain characteristic with another ejector cell having a different characteristic.

[0035] Accordingly, the inventive ejector-type vacuum pump allows for adaptation thereof from being intended for high pressure feeding to being intended for low pressure feeding, from being intended for a high flow of air to being intended for a low flow of air, and from being intended for generation of a high vacuum level to being intended for generation of a lower vacuum level.

[0036] Accordingly, in yet an aspect the present invention relates to a method of adapting a pump characteristic or a performance of an ejector-type vacuum pump 1, the ejector-type vacuum pump 1 being configured to be able to accommodate therein two or more ejector cells 30, comprising the step of: inserting into the ejector-type vacuum pump 1, from an outside of the ejector-type vacuum pump 1, a second ejector cell 30 exhibiting a second ejector characteristic, the second ejector characteristic being different from a first ejector characteristic exhibited by a first ejector cell 30 of the ejector-type vacuum pump 1.

[0037] Further embodiments and advantages of the invention will be apparent from the following detailed description and appended claims. As used herein, the term "ejector cell" is used to refer to a single ejector, i.e. an individual ejector, which has one or more vacuum generating stages. The injector cell is configured to be individually, and independently of any other injector cell or cells present in the inventive pump, removed from and inserted into, respectively, the inventive ejector-type vacuum pump 1.

[0038] The term "ejector-cell replacement insert" is used herein to denote a structure having a similar geometry as an ejector cell, which serves to plug an ejector cell seat by way of insertion of the ejector-cell replacement insert into the ejector cell seat. Accordingly, when inserted into an ejector cell seat 85, the ejector-cell replacement insert will prevent air from passing through the ejector cell seat in the pump. Thus, an inventive ejector-cell replacement insert has no ejector characteristics.

[0039] BRIEF DESCRIPTION OF THE ATTACHED DRAWINGS

[0040] 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 ejectorcells 30, one of which ejector-cells has been removed, leaving open an opening 80 in the vacuum pump housing 20.

[0041] 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 an ejector-cell seat 85, comprising four cell seat portions 85a, 85b, 85c, and 85d, in which seat the removed ejector cell is to be accommodated, can be seen.

[0042] Figure 3 shows a side view of the removed ejector-cell 30 in FIG. 1.

[0043] 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.

[0044] Figure 6 shows a cross-sectional view of the ejector-cell replacement insert 35 in FIG. 5 along the line C-C.

[0045] DETAILED DESCRIPTION OF THE INVENTION

[0046] 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 be able to accommodate three or more ejector cells, such as 3, 4, 5 or 6 ejector cells, and consequently exhibits a corresponding number of ejector cell seats 85 and of openings 80. 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.

[0047] The number of stages of an inventive multi-stage ejector-type vacuum pump 1 can typically be 2, 3 or 4. An ejector cell 30 for use in the inventive ejector-type vacuum pump 1 exhibits same number of stages as the pump 1. 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 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.

[0048] 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.

[0049] 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.

[0050] The ejector-cell replacement insert 35 has a geometric form similar to that of an ejectorcell 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.

[0051] 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 ejectorcell 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. 1-6, or a quick release coupling, such as e.g. of bayonet-type (not shown). An ejector-cell 30 and an ejector-cell replacement insert 35 should preferably exhibit similar locking portions 90 using similar locking means for securing the locking portion 90 to the housing 20. Thereby, an ejector-cell 30 can be unlocked and removed from an opening 80 in the housing 20, and an ejector-cell replacement insert 35 can be inserted into same opening 80, and locked to the housing 20, replacing the ejector-cell 30, and vice versa.

[0052] 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).

[0053] 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.

[0054] 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.

[0055] 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. 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.

[0056] 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 85a, 85b, 85c, and 85d 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.

[0057] For each nozzle of an ejector cell 30, one or more inlet openings 76 for each stage of the ejector cell are provided on the ejector cell aft of the nozzle.

[0058] 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.

[0059] 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.

[0060] 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 screwdriver, e.g. as shown in FIGS. 1, 2, 4, and 6.

[0061] For a desired quick response time of the inventive ejector pump 1, the inner volume of the pump should be kept small.

[0062] While the inlet 40 for pressurized air, exhaust opening 55, and suction opening 50 have been illustrated in the FIGS. 1 and 2 as being located at one and the same side of the housing 20, it will be clear to the skilled reader from the instant disclosure that the exhaust opening 55 could alternatively be located on another side of the housing 20 than the inlet 40 for pressurized air, and suction opening 50, and that also the inlet 40 for pressurized air could alternatively be located on another side of the housing 20 than the exhaust opening 55, and the suction opening 50.

[0063]

[0064] 1 ejector-type vacuum pump

[0065] 10 pump body

[0066] 20 vacuum pump housing

[0067] 25 rear wall of housing 20

[0068] 26 outer surface of the rear wall 25

[0069] 30 removable ejector cell

[0070] 35 ejector-cell replacement insert

[0071] 40 inlet for pressurized air

[0072] 45 exhaust chamber

[0073] 47 common vacuum chamber

[0074] 47i first stage vacuum chamber

[0075] 472second stage vacuum chamber

[0076] 473third stage vacuum chamber

[0077] 50 suction opening

[0078] 55 exhaust opening

[0079] 60 check-valve

[0080] 65 valve opening plate

[0081] 67 valve opening

[0082] 70 seals

[0083] 75 first nozzle of ejector cell

[0084] 76 ejector-cell inlet opening

[0085] 77 ejector-cell exhaust opening

[0086] 80 ejector-cell opening

[0087] 85 ejector-cell seat

[0088] 90 locking portion

[0089] 100 outer surface of locking portion 90

[0090] 110 tool coupling portion in outer surface of locking portion

[0091] A-A section through vacuum pump and removed ejector cell

[0092] B-B section through an ejector cell

[0093] C-C section through an ejector-cell replacement insert

Claims

CLAIMS1. 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 therein the pump body (10); a first ejector cell (30) having one or more vacuum generating stages; two or more ejector cell seats (85) formed in the pump body (10), each one of said two or more ejector cell seats (85) being configured to be able to accommodate therein an ejector cell (30), a total number of the ejector cell seats (85) corresponding to a total number of the ejector cells (30) which the pump is configured to be able to accommodate; an inlet (40) provided in the housing (20) configured to receive pressurized air; a suction opening (50) provided in the housing (20); seals (70), configured to air-tightly seal the first ejector cell (30) to the pump body (10), said first ejector cell (30) being removable from the pump body (10) and configured to be secured in an operational position within the housing (20) in a first ejector cell seat (85) of said two or more ejector cell seats (85) formed in the pump body (10), wherein the housing (20), in a rear wall (25) thereof, has a separate opening (80) for each one of said two or more ejector cell seats (85), the separate opening (80) being configured to allow for insertion into the cell seat (85) and removal from the cell seat (85) of an ejector cell (30) through said separate opening (80), characterized in that the pump body (10) has one or more vacuum chambers (471, 472, 47s), wherein each one of the one or more vacuum chambers (47i, 472, 47s) fluidly communicates with the suction opening (50), the pump body (10) additionally selectively comprises a second ejector-cell (30) having same number of vacuum generating stages as the first ejector-cell (30) in a second ejector cell seat (85) of said two or more ejector cell seats (85) formed in the pump body (10) or a first ejector-cell replacement insert (35) in said second ejector cell seat (85) of said two or more ejector cell seats (85) formed in the pump body (10),each vacuum chamber (47i, 472, 47s) is configured to house therein a selected vacuum generating stage of the first ejector cell (30), and of the second ejector cell (30) when present, wherein the seals (70) are additionally configured to air-tightly seal the second ejector cell (30), when present, to the pump body (10), and, the first ejector-cell replacement insert (35), when present, to the pump body (10), wherein the second ejector cell (30), when present, is removable from the pump body (10) and configured to be secured in an operational position within the housing (20) in the second ejector cell seat (85) of said two or more ejector cell seats (85) formed in the pump body (10), and wherein the first ejector-cell replacement insert (35), when present, is removable from the pump body (10) and configured to be secured within the housing (20) in the second ejector cell seat (85) of said two or more ejector cell seats (85) formed in the pump body (10) in a position air-tightly plugging the second ejector cell seat.

2. The ejector-type vacuum pump (1) of claim 1, wherein each one of the first ejector cell (30), the second ejector cell (30) when present, and the first ejector-cell replacement insert (35) when present, 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 each one of the first ejector cell (30), the second ejector cell (30) when present, and the first ejector-cell replacement insert (35) when present.

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 an 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 markingprovided 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 each one of the first ejector cell (30), the second ejector cell (30) when present, and the first ejector-cell replacement insert (35) when present.

7. The ejector-type vacuum pump (1) of any one of claims 1-6, comprising a first ejector-cell replacement insert (35).

8. The ejector-type vacuum pump (1) of claim 7, wherein the first 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 an outer surface (100) of a locking portion (90).

9. 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, wherein the respective vacuum chamber (47i, 472, 47s) of each one of the stages is fluidly connected to the suction opening (50) via a common vacuum chamber (47).

10. The multi-stage ejector-type vacuum pump (1) of claim 9, 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).

11. The multi-stage ejector-type vacuum pump (1) of claim 9, comprising a separate respective common check-calve (60) for each one of the stages configured to prevent a flow of air from exiting from a stage into the common vacuum chamber (47) through a valve opening (67).

12. A method of adapting a pump characteristic and / or a performance of an ejector-type vacuum pump (1), the ejector-type vacuum pump (1) being configured to be able to accommodate therein two or more ejector cells (30), comprising the step of: inserting into the ejector-type vacuum pump (1), from an outside of the ejector-type vacuum pump (1), a second ejector cell (30) exhibiting a second ejector characteristic, the second ejector characteristic being different from a first ejector characteristicexhibited by a first ejector cell (30) of the ejector-type vacuum pump (1).

13. The method of claim 12, additionally comprising the step of: locking a locking portion (90) of the inserted second ejector cell (30) into an opening (80) of the pump (1), wherein the locking step is preferably carried out without using a tool, but with e.g. a coin.

14. A method of adapting a pump performance of an ejector-type vacuum pump (1), the ejector-type vacuum pump (1) being configured to be able to accommodate therein two or more ejector cells (30), comprising the step of: inserting into the ejector-type vacuum pump (1), from an outside of the ejector-type vacuum pump (1), an ejector-cell replacement (35) exhibiting no ejector performance.

15. The method of claim 14, additionally comprising the step of: locking a locking portion (90) of the inserted ejector-cell replacement (35) into an opening (80) of the pump (1), wherein the locking step is preferably carried out without using a tool, but with e.g. a coin.

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