Modular vacuum ejector system

Abstract

The disclosed modular vacuum ejector system (1) consists of two vacuum ejector pumps (2, 4). The first pump (2) has a vacuum collecting compartment (12), a pressurized gas inlet (6), and two stages (8, 10) with ejector nozzles (20), expansion nozzles (22), and vacuum cavities (24, 32). The second pump (4) has a pressurized gas inlet (14), a vacuum collecting compartment (18) with a channel (39), and a stage (16) with ejector nozzle (36), expansion nozzle (38), and vacuum cavity (40). The vacuum cavities of both pumps are connected to their respective collecting compartments through feedthroughs (42, 44). An open-ended feedthrough (46) connects the vacuum cavity (40) of the second pump to its collecting compartment and links to the open end of a feedthrough (44) from the first pump. A blocking element (5) seals the open end of the other feedthrough (42) of the first pump, creating a modular vacuum system with interconnected stages.

Description

[0001] Modular Vacuum Ejector System

[0002] Technical Field

[0003] The invention relates to the field of vacuum ejector systems for generating a vacuum using a source of compressed gas. The present invention also relates to a method of generating a vacuum with comparably high vacuum volume flow rate and / or vacuum level so that the vacuum ejector system can be used for specific and various applications.

[0004] Background of the Invention

[0005] Ejector vacuum pumps, which use a source of compressed gas, typically air, in order to generate a vacuum and thus a negative pressure in a cavity or space are known. Gas driven ejectors function by accelerating a high-pressure gas provided at an inlet via a drive nozzle or ejector nozzle. The gas is ejected at the ejector nozzle into a vacuum cavity that comprises a gap through which the gas travels at high speed from the outlet of the ejector nozzle to an inlet of an expansion nozzle or outflow passage across the gap. Gas that is within the vacuum cavity where the gap is positioned is entrained in the high-speed flow of compressed gas and the flow or jet of high-speed gas drags the gas from within the vacuum cavity into the expansion nozzle or outlet nozzle thereby generating a vacuum in the vacuum cavity and any space that is fluidically connected to the vacuum cavity such as for example a vacuum collecting compartment.

[0006] It is also known to use vacuum ejector pumps with several stages in order to generate a vacuum comparably fast by emptying spaces of gas using comparably large nozzles and combining stages with comparably small nozzles to generate a deep or low vacuum and thus a high negative pressure. Typically, the small nozzles and expansion nozzle combinations are thereby arranged close to the inlet where the compressed gas is provided and thus upstream as seen in a flow direction of highspeed gas along the multistage vacuum ejector pump. The vacuum provided by such ejector pumps is typically collected in a vacuum collecting compartment that is in fluid connection with each vacuum cavity of each stage. The vacuum collecting compartment is used to collect the generated vacuum of all the stages and from the vacuum collecting compartment a vacuum can be generated in a target volume. Valves can be used in order to close off stages that have served their purpose when certain vacuum levels and thus negative pressure levels are achieved. Such valves are typically no-return valves, and they ensure that higher vacuum levels (higher negative pressures) than the one provided by the stage at hand, typically a stage with a rather big drive- and expansion nozzles, can be achieved. Stages with comparably bigger drive- and expansion nozzles compared to the first drive - or ejector nozzle typically generate a higher vacuum flow rate while stages close to the inlet or compressed gas source generate a high vacuum level (high negative pressure). Herein the term small nozzle and big nozzle refers to the diameter or cross-sectional area of such a nozzle.

[0007] Usually, the objects of achieving a high-level vacuum and a high vacuum flow contradict one another. A high-level vacuum (high negative pressure) can be achieved at the drawback of having a low vacuum volume flow rate and a high vacuum volume flow can typically be achieved at the drawback of having a comparably low absolute vacuum (low negative pressure). Thus, the nozzles and therewith the vacuum ejector pumps may either be tailored to achieve a high-level vacuum or a high vacuum flow rate depending on the application. A high negative pressure is usually required in order to generate a high suction force and thus a maximum pressure difference with ambient pressure. Typically, such high negative pressures can be used with robots to lift heavy objects that do not let gas pass through at the point of contact with the vacuum adapter, which is typically a suction cup or the like. When such objects having a non-porous surface such as metal, glass or plastic are lifted using a vacuum generating suction system, then the vacuum ejector pump may even be turned off once the object is connected at the vacuum adapters, since the object do not let pass gas through their surface that is sucked onto the vacuum adapter. The other application thus a high vacuum volume flow is typically desired when comparably big volumes such as tanks or the like need to be vacuumized. A high vacuum volume flow rate is also desirable when quick turnarounds are needed, for example when a packaging robot needs to lift a certain number of objects per time period. The high-volume vacuum flow allows thereby to generate a vacuum quickly for picking up the object and to release the object quickly once it is placed where it is supposed to be. In order to provide the stream of fluid across each stage of a vacuum ejector pump, the series of ejector nozzles and expansion nozzles are provided along a continuous channel, the flow direction of the highspeed gas stream, whereby the cross-sectional area of the nozzles are increasing from the first stage to the last stage, thereby successively accelerating the air flow along each stage.

[0008] An example of a multistage vacuum ejector pump is shown for example in the US 2017 / 0152868 A1 publication.

[0009] In the past various efforts have been made to provide multistage ejector pumps that provide both a high vacuum volume flow and a high vacuum level. Such multistage ejector pumps typically comprise three or more nozzles arranged in series within a housing, each neighbouring pair of nozzles in the series defining a respective stage across which a negative pressure is generated in the gap between outlet and inlet of neighbouring nozzles and within a vacuum cavity. As mentioned above in such multistage vacuum ejector pumps the first stages typically provide a high-level vacuum while the subsequent stages provide a high- level vacuum flow. No-return valves at the subsequent stages ensure that a high- volume vacuum flow can be provided in the beginning of an evacuation process while when these no-return valves close a high-level vacuum can be achieved later on at the cost of having a comparably lower vacuum volume flow rate. This is shown in figure 1 , which shows a typical vacuum flow versus vacuum level curve that can be achieved with multistage ejector pumps according to the prior art. Figure 1 illustrates well how the vacuum flow rate is rather high in the beginning of the evacuation process while it then flattens out towards higher vacuum levels, since the no-return valves of the subsequent stages are closing one after the other, which is illustrated by the change of inclinations 100 in the curve. The curve illustrated in figure 1 has some drawbacks in particular when a robot is lifting porous material using a vacuum. When lifting porous material such as cement bags, cardboard, Styrofoam, insulation boards and so on, at least some multistage ejector vacuum pumps reach their limit and it is not possible to lift and move porous material with them since the vacuum volume flow rate is not sufficient at the relevant vacuum level. The same or a similar situation can occur when material with comparably rough surfaces have to be lifted using vacuum for example on a robot. The suction cup will not close tightly on the rough surface in such a situation, which means that not tight and stable vacuum can be established, which in turn means that the vacuum pump needs to be constantly on to keep on generating the vacuum. This means in other words that lifting robots or packaging robots or the like can drop the porous material or the material with rough surface, which causes problems in the entire supply- and value chain. A higher vacuum volume flow rate for various vacuum levels may of course be achieved by using a higher initial gas pressure at the inlet and / or a higher gas flow and / or a bigger ejector pump but many industries require energy saving vacuum ejector systems that are versatile and comparably small so that they can be placed close to the position, for example a suction cup on a robot, where the vacuum is needed.

[0010] Summary of the Invention

[0011] In view of the above it is desirable to provide a vacuum ejector system that allows to adjust the vacuum flow rate at various vacuum levels.

[0012] An object of the present invention is to provide a vacuum ejector system that is versatile, efficient and economic.

[0013] A further object of the present invention is to provide a method for controlling vacuum volume flow rate and vacuum strength (vacuum level) in a modular vacuum ejector system that allows to adjust and configure the modular vacuum ejector system for various purposes while saving energy and thus gas pressure, while at the same time providing a comparably small modular vacuum ejector system.

[0014] In view of the above-mentioned problems the inventor of the present invention has discovered that it is possible to use at least two multistage vacuum ejector pumps, a fist vacuum ejector pump and a second vacuum ejector pump, the first vacuum ejector pump comprising at least two stages and the second vacuum ejector pump comprising at least one stage arranged so that at least one stage of the first vacuum ejector pump can be connected to at least one stage of the second vacuum ejector pump in order to enhance vacuum volume flow at specific vacuum levels or to adjust vacuum levels at various vacuum volume flow rates. The firstand the second vacuum ejector pump may use the same source of compressed gas and the vacuum volume flow may be controlled and adjusted by guiding the vacuum flow within the at least two vacuum ejector pumps according to the specific need of the present application by using some of the stages of the second vacuum ejector pump and by sealing of other stages of the second vacuum ejector pump, depending on the specifications of the task at hand. The inventor of the present disclosure has further discovered that is possible to increase vacuum flow rate by opening later stages of the second vacuum ejector pump and by sealing off earlier stages of the second vacuum ejector pump and that is possible to adjust vacuum level by opening early stages of the second vacuum ejector pump and sealing off later stages of the second vacuum ejector pump. The terms early and late hereby referring to upstream a flow direction (early) of the highspeed gas flow and downstream a flow direction (late) of the highspeed gas flow in the second (or first-) vacuum ejector pump. The inventor has further discovered that is possible to distribute and change or adjust such a vacuum flow via a vacuum collecting compartment of the second vacuum ejector pump.

[0015] Disclosed herein is a modular vacuum ejector system comprising a first vacuum ejector pump having a vacuum collecting compartment, an inlet for pressurized gas, a first stage and a second stage arranged in series, the first stage comprising at least one ejector nozzle in fluid communication with the inlet, at least one expansion nozzle and a vacuum cavity. The second stage comprises at least one expansion nozzle and a vacuum cavity, the vacuum cavity of the first stage and the vacuum cavity of the second stage being fluidly connected to the vacuum collecting compartment. The vacuum cavities each comprise a feed through connected with one end to the vacuum collecting compartment and each of the feed throughs having an open end. An outlet of the at least one ejector nozzle of the first stage is directed into the vacuum cavity of the first stage and an inlet of the expansion nozzle of the first stage is arranged in the vacuum cavity of the first stage. An outlet of the expansion nozzle of the first stage is arranged in the vacuum cavity of the second stage and an inlet of the expansion nozzle of the second stage is arranged in the vacuum cavity of the second stage. Between the inlets and outlets of the ejector and expansion nozzles a gap is present. The modular vacuum ejector system further comprises a second vacuum ejector pump having an inlet for pressurized gas, a vacuum collecting compartment comprising a channel, a first stage comprising at least one ejector nozzle having an outlet, at least one expansion nozzle having an inlet and a vacuum cavity in which the outlet and inlet are arranged leaving a gap between one another. The vacuum cavity of the second vacuum ejector pump comprising an opening for connecting the vacuum cavity to the vacuum collecting compartment of the second vacuum ejector pump and from the vacuum collecting compartment via the channel to the open end of one of the feed throughs of the first vacuum ejector pump. The modular vacuum ejector system further comprises at least one blocking element being designed to seal the open end of the other of the feed throughs of the first vacuum ejector pump.

[0016] A vacuum ejector system according to the above allows to control and steer vacuum volume flow rate and / or vacuum level. Connecting the first vacuum ejector pump and the second vacuum ejector pump so that at least one stage of the first vacuum ejector pump can be connected to at least one stage of the second vacuum ejector pump can improve vacuum depth or vacuum volume flow.

[0017] In an embodiment the first vacuum ejector pump and the second vacuum ejector pump each comprise a plurality of stages.

[0018] The stages and therewith the diameter of the nozzles increase in size along a flow direction of a highspeed gas stream. This means that the vacuum volume flow rate of each stage increases along the flow direction while the vacuum level that can be provided is lower the longer downstream the highspeed gas stream it is positioned.

[0019] In an embodiment the second vacuum ejector pump has at least two stages each of them comprising a vacuum cavity with an opening into the vacuum collecting compartment, the channels of the at least two stages of the second vacuum ejector pump being connectable the open ends of the feed throughs of the two stages of the first vacuum ejector pump and whereby at least one open end of one of the feed throughs of the first vacuum ejector pump is sealable using the blocking element.

[0020] Providing two stages in the second vacuum ejector pump increases the flexibility and adjustability of the modular vacuum ejector system. Thus, the more stages the first vacuum ejector pump and the second vacuum ejector pump comprise the higher the adjustability. However, it might not make sense to provide a very high number of stages in the vacuum ejector pumps a reasonable number of stages may be within 2 - 6 stages per vacuum ejector pump.

[0021] In a further embodiment each of the first vacuum ejector pump and the second vacuum ejector pump may comprise multiple stages and wherein any of the stages of any of the first - or second vacuum ejector pump can be sealed using a suitable number and type of blocking elements either prior or after the vacuum collecting compartment of the second vacuum ejector pump.

[0022] The above embodiment provides even more flexibility and adjustability in controlling and guiding vacuum volume flow rate and vacuum flow.

[0023] In an embodiment the first vacuum ejector pump and the second vacuum ejector pump may share a compressed gas source.

[0024] The shared compressed gas source may a compressor, a pressure chamber or just a line providing gas pressure.

[0025] This may help to save energy (gas pressure).

[0026] The gas used may be air.

[0027] They may also each have a separate compressed gas source in order to increase capacity of the vacuum ejector system.

[0028] The size and therewith the vacuum volume flow rate of the first stage, the second stage and so on of each of the first vacuum ejector pump and the second vacuum ejector pump continuously increase along a flow direction of a highspeed gas stream.

[0029] Disclosed herein is also a method for controlling vacuum flow and vacuum level in a modular vacuum ejector system comprising a first vacuum ejector pump and a second vacuum ejector pump. The first vacuum ejector pump comprising at least two stages and the second vacuum ejector pump comprises at least one stage, the method comprising the steps of:

[0030] - Arranging the first vacuum ejector pump so that at least one stage of the first vacuum ejector pump is connectable to at least one stage of the with the second vacuum ejector pump;

[0031] - Providing matching channels in a vacuum collecting compartment in the second vacuum ejector pump, which channels can be connected to feed throughs of the first vacuum ejector pump;

[0032] - Connecting a vacuum collecting compartment of the second vacuum ejector pump to feed throughs of the first vacuum ejector pump using the channels so that fluid or gas can pass from the vacuum collecting compartment of the second vacuum ejector pump to vacuum cavities of the first vacuum ejector pump and therewith the vacuum collecting compartment of the first vacuum ejector pump;

[0033] - Adjusting vacuum volume flow rate at different vacuum levels in a vacuum collecting compartment of the first vacuum ejector pump of the vacuum ejector system using at least one blocking element capable of sealing of vacuum flow in any the channels and / or feed throughs of the first vacuum ejector pump.

[0034] This method allows to adjust vacuum volume flow rate and / or vacuum level in the modular vacuum ejector system, which provides a high flexibility and adjustability for the use case.

[0035] In an embodiment the method may be used to adjust a modular vacuum ejector system comprising a first vacuum ejector pump and a second vacuum ejector pump, whereby each comprise a plurality of stages to further adjust and control the vacuum flow at different vacuum levels. Such a method may further comprise the steps of

[0036] - Providing a number of blocking elements of matching types; and

[0037] - Sealing at least one stage either prior to or after the collecting compartment of the second vacuum ejector pump using at least one of the number of blocking elements.

[0038] In another embodiment the number of provided blocking elements may match the number of stages of the second vacuum ejector pump.

[0039] In a further embodiment the method may comprise the step of increasing the vacuum volume flow rate of the modular vacuum ejector system by removing blocking elements from the channels or feed throughs of at least two of the stages with a greatest size of the second vacuum ejector pump, which stages are arranged downstream along a flow direction of the highspeed gas stream, preferably farthest away from an ejector nozzle of the first vacuum ejector pump.

[0040] This may allow to adjust vacuum volume flow rate at vacuum levels of 20% to 50% vacuum (100% is absolute vacuum thus minus 1013 mbar at sea level).

[0041] The invention has now been described using some embodiments and examples. Specific embodiments will now be described referring to the drawings. It is however important to note that the concept described herein is rather general and in that the enclosed embodiments are also not to be considered limiting but rather as illustrating a general concept to optimise vacuum volume flow rate and / or vacuum level for various applications.

[0042] Brief Description of the Drawings

[0043] The present invention will now be described, for exemplary purposes, in more detail by way of an embodiment(s) and with reference to the enclosed drawings, in which:

[0044] Fig. 1 schematically illustrates a vacuum diagram that is achieved by multistage vacuum ejector pumps according to the prior art; Fig. 2 schematically illustrates a cross sectional view of an embodiment of a vacuum ejector system according to the invention;

[0045] Fig. 3 schematically illustrates a cross sectional view of another embodiment of a vacuum ejector system according to the invention;

[0046] Fig. 4 schematically illustrates a cross sectional view of another embodiment of a vacuum ejector system according to the invention;

[0047] Fig. 5 schematically illustrates a cross sectional view of the embodiment of figure 4 in a different configuration;

[0048] Fig. 6 schematically illustrates a cross sectional view of the embodiments of figures 4 and 5 in still a different configuration;

[0049] Fig. 7 schematically illustrates a diagram that can be achieved using the vacuum ejector system according to the present invention in light of figure 1 , which shows the prior art; and

[0050] Fig.8schematically illustrates a method according to the present invention.

[0051] Detailed Description

[0052] Figure 2 illustrates a vacuum ejector system 1 comprising a first vacuum ejector pump 2 and a second vacuum ejector pump 4. The first vacuum ejector pump 2 comprises a first stage 8 and a second stage 10 and may thus be called a two- stage vacuum ejector pump 2. The first vacuum ejector pump 2 and the second vacuum ejector pump 4 may be designed as modular pumps, which means that stages may be added or taken away depending on the specifications of the work to be performed or the job at hand. The first vacuum ejector pump 2 comprises a vacuum collecting compartment 12 having an inlet 13 that can be connected to a vacuum hose or a suction cup or the like. Each of the embodiments disclosed herein comprises such an inlet 13 even though it may not be illustrated or numbered in each embodiment. The first vacuum ejector pump 2 further comprises an inlet 6, which received pressurized gas, and which is arranged prior to the first stage 8. Each of the first and second stages 8, 10 comprise a vacuum cavity 24, 32 and a feed through 42, 44. From the inlet an ejector nozzle 20 or drive nozzle 20 extends into the vacuum cavity 24 of the first stage 8 (S1 ). From the vacuum cavity 24 of the first stage 8 an expansion nozzle 22 having an expanding cross-sectional area extends into the vacuum cavity 32 of the second stage 10 (S2). An outlet of the ejector nozzle 20 and the inlet of the expansion nozzle 22 are arranged at a distance from one another generating a gap in the vacuum cavity 24 so that surrounding gas can be entrained into the highspeed gas flow generated in the ejector nozzle 20 and the expansion nozzle 22. The highspeed gas flow is indicated with the flow direction fd. The process and vacuum generation continues in the second stage 10 where an outlet of the expansion nozzle 22 is entering into the vacuum cavity 32 of the second stage 10 and then into an inlet of a further expansion nozzle 30, which is bigger than the previous expansion nozzle 22 as measured in cross sectional area. The outlet and inlets in the vacuum cavity 32 of the second stage 10 are again arranged at a gap from one another so that surrounding air in the vacuum cavity 32 of the second stage 10 is entrained in the highspeed gas flow before it is ejected from the expansion nozzle 30 of the second stage 10. The feed through 44 of the second stage comprises a no-return valve or valve 34 that closes once a certain negative pressure is reached so that the first stage can continue to reduce the (negative) pressure to an even lower level. It is to be noted that the no-return valve 34 is only needed when a tight or sealed vacuum application is present for lifting porous material or material with a rough surface this no-return valve 34 is not needed.

[0053] Figure 2 further illustrates how the second vacuum ejector pump 4 may comprise an inlet valve 23 at the gas pressure source or inlet. Such an inlet valve 23 may even be provided at the first vacuum ejector pump 2 depending on configuration and need. The inlet valve may allow to steer and control the vacuum volume flow and vacuum depth even further. Any other subsequent vacuum ejector pump arranged after or connected to a stage of the second vacuum ejector pump 4 may comprise such an inlet valve 23. Further and even though not shown in each embodiment herein, each embodiment may comprise such an inlet valve 23 at the inlet of the gas pressure source in any of the first-, second or third vacuum ejector pump 2, 4 or any other subsequent vacuum ejector pump.

[0054] The ejected gas from the last or latest stage may be collected and subjected to pressure again by adding energy so that it can be used to drive the vacuum generating process again. The feed throughs 42, 44 of the first vacuum ejector pump 2 extend with one of their respective ends into the vacuum collecting compartment 12 and with their other ends into open ends at bottom of the first vacuum ejector pump 2. At the open ends of the first vacuum ejector pump 2 a vacuum collecting compartment 18 of the second vacuum ejector pump 4 can be connected. The second vacuum ejector pump 4 is illustrated as having one stage 16 (S1 ). In the illustration of figure 2 the second vacuum ejector pump 4 comprises similarly to the first vacuum ejector pump 2 an inlet 14 to receive pressurized gas, which inlet 14 is connected via an ejector nozzle 36 or drive nozzle 36 to a vacuum cavity 40 of the one stage 16. The outlet of the ejector nozzle 36 is arranged in the vacuum cavity 40 and an inlet of an expansion nozzle 38 is also arranged in the vacuum cavity 40 of the one stage 16 at gap from the outlet of the ejector nozzle 36. The vacuum cavity 40 is fluidically connected to the vacuum collecting compartment 18 via a feed through46 and the vacuum collecting cavity 18 is further fluidically connected to the feed through 44 of the second stage 10 of the first vacuum ejector pump 2. The other open end of the first vacuum ejector pump 2 of the feed through 42 of the first stage 8 is sealed off using a blocking element 5. Similarly, the open end of the second vacuum ejector pump 4 is sealed using a blocking element 5. This open end of the second vacuum ejector pump 4 may however be open if a third vacuum ejector pump (not shown) is connected to the open end of the second vacuum ejector pump 4. The second vacuum ejector pump 4 helps therewith to increase vacuum volume flow in the second stage 10 of the first vacuum ejector pump 2 using one and the same compressed gas source through the respective inlets 6, 14.

[0055] The skilled person will further understand that the second vacuum ejector pump 4 can also be connected to the first stage 8 of the first vacuum ejector pump 2 while sealing off the feed through 44 of the second stage 10 of the first vacuum ejector pump 2 in order to generate a deeper vacuum (higher vacuum level) and thus a higher negative pressure still using one and the same compressed gas source. The vacuum ejector system 1 comprising the first vacuum ejector pump 2 and the second vacuum ejector pump 4 and the blocking element 5 is thus versatile and highly flexible in its use as it can be adapted and adjusted to various specific applications, especially if the first vacuum ejector pump 2 and / or the second vacuum ejector pump 4 both comprise several stages. This is now explained referring to figure 3.

[0056] Figure 3 illustrates the first vacuum ejector pump 2 in the same configuration as figure 2 and is herewith not further explained in detail. The same reference numbers refer to the same parts as under figure 2. The difference in this configuration is that the second vacuum ejector pump 4’ comprises two stages 16, 19, (or S1 , S2) the first stage 16 being capable of providing a deeper vacuum while the second stage 19 is design to provide a higher vacuum volume flow rate due to bigger diameter of the corresponding ejector nozzle 38 and expansion nozzle 50. The second stage 19 also comprises a no-return valve 56 at the opening 54 that leads into the vacuum collecting compartment 18’. The vacuum collecting compartment 18’ is fluidically connected to the feed throughs 42, 44 of the first vacuum ejector pump 4 while the feed through 42 of the first stage 8 of the first vacuum ejector pump 2 is sealed using the blocking element 5. Also, the open ends of the second vacuum ejector pump 4’ are sealed off using blocking elements 5. These blocking elements 5 or sealing elements 5 may however be removed if a third vacuum ejector pump (not shown) is connected to the second vacuum ejector pump 4’. This means that the configuration of figure 3 illustrates a higher vacuum volume flow rate than could be achieved with the first vacuum ejector pump 2 alone. Other configurations may be possible for instance by sealing of the feed through 44 of the second stage of the first vacuum ejector pump 2 or by leaving both feed throughs 42, 44 open thereby generating an even higher flow and at the same time achieving a higher vacuum level at the cost of loosing energy in the gas flow, thus providing a vacuum level that it totally a bit lower than the first stage 8 of the first vacuum ejector pump 2 can theoretically provide.

[0057] Increasing the number of stages in both of the first - and the second vacuum ejector pumps 2, 4, 4’ may lead to even more adjustment possibilities as shown in figures 4 and 5.

[0058] In general, the ejector nozzles 20, 36 and the expansion nozzles 22, 38 30, 50 may each comprise a compression part a straight or continuous part and then an extensional part so that the air is first compressed after each stage S1 , S2 before the air is then expanded and therewith accelerated again. This is also visible in figures 4 to 6, where each nozzle comprises a compression part, a continuous or straight part and then an expansion part into the next vacuum cavity.

[0059] Figures 4 to 6 illustrate a vacuum ejector system 1 comprising a first vacuum ejector pump 2’ and a second vacuum ejector pump 4” arranged in parallel. Each of the first vacuum ejector pump 2’ and the second vacuum ejector pump 4” comprising four stages S1 , S2, S3 and S4. Stage S1 is designed to provide a deep vacuum (high vacuum level) with a comparably low vacuum volume flow while successive S2, S3, S4 provide a lower vacuum (lower vacuum level) but a greater vacuum volume flow rate. The arrows A in figure 4 illustrate the vacuum flow in the vacuum ejector system 1. The stages S1 , S3 and S4 of the second vacuum ejector pump 4” are sealed using blocking elements 5”, 5’ at the feed throughs 42’, 43, 45 of the first vacuum ejector pump 2’. Each stage S1 , S2, S3, S4 comprises two ejector nozzles 20’, 36’ in the cross-sectional view and four ejector nozzles 20’, 36’ in total per stage S1 , S2, S3, S4. Correspondingly the expansion nozzles may also be adapted accordingly in numbers. The present disclosure encloses any number of ejector- and expansion nozzle number and combination even non-matching number combinations.

[0060] From figure 4 it becomes clear that other configurations and therewith other vacuum flow rates and vacuum levels can be achieved using the vacuum ejector system 1 of illustrated in figure 4, by using more or less blocking elements 5’ or by adapting the position of the blocking elements 5’. For example, by removing plugs or blocking elements 5’, 5’ from the feed throughs 43, 45 of the stages S3 and S4 the vacuum volume flow rate may further be increased, as illustrated in figure 5. In figure 4 the feed throughs 42’ of the second vacuum ejector pump 4” are closed using a sealing plate 57 that extends over all four stages S1 , S2, S3 and S4. The sealing plate 57 is hereby provided as a separate unit or part of the vacuum ejector system 1 .

[0061] Figure 5 illustrates how only the blocking element 5” of the first stage S1 is installed in the vacuum ejector system 1. This means that the vacuum flow is changed to the one illustrated in figure 5 in which the vacuum flow is going through stages S4, S3 and S2 in both vacuum ejector pumps 2’, 4” and only through S1 in the first vacuum ejector pump 2’. The effect of such a changed vacuum flow distribution is that the vacuum flow rate is increased. It is to be noted that each of the stages S2, S3 and S4 in both the first vacuum ejector pump 2’ and the second vacuum ejector pump 4” comprise no return-valves 34’, 56’ so that these stages S2, S3 and S4 are automatically closed when specific negative pressures (vacuum levels) are reached. It is further to be noted that these specific negative pressures vary from stage to stage, typically S4 is closed off via the no-return valves 34’, 56’ at relatively low negative pressure and then S3 is closed off at a lower negative pressure and S2 is closed off at an even lower negative pressure so that then S1 can provide the lowest negative pressure (highest vacuum level) of the vacuum ejector system 1 . The vacuum flow in figure 5 is indicated with the arrows A’.

[0062] The exemplary configuration in figure 5 allows to steer and control the vacuum flow rate at specific vacuum levels (negative pressures), as is illustrated in figure 6.

[0063] In figures 2 to 6 the flow direction fd of the highspeed gas stream is further indicated. The size of the stages 8, 10, 16, 19, S1 , S2, S3, S4 and therewith the diameter of the expansion and ejector nozzles increase continuously along the flow direction fd of the high-speed gas. This means that stages downstream the flow direction fd generate a higher vacuum volume flow while the stages upstream the flow direction generated a higher vacuum level (higher negative pressure).

[0064] Figure 6 illustrates a similar vacuum ejector system T as the one in figures 4 and 5 but in a different configuration. In figure 6 the vacuum flow is changed according to the arrows A”. The vacuum collecting compartment 12’ of the first vacuum ejector pump 2’” and the vacuum collecting compartment 18” of the second vacuum ejector pump 4’” are configured to collect the vacuum generated in the respective pumps. In the illustrated case the second stage S2, third stage S3 and the fourth stage S4 of the second vacuum ejector pump 4’” are sealed using blocking elements 5’” prior to the vacuum collecting compartment 18” of the second vacuum ejector pump 4’”. Only the first stage S1 of the second vacuum ejector pump 4”’ is active, while the first stage S1 , the third stage S3 and the fourth stage S4 of the first vacuum ejector pump 2”’ are sealed using blocking elements 5’, 5”. This generates a different vacuum flow from the configurations illustrated in figures 4 and 5. The open ends or feed throughs of the second vacuum ejector pump 4”’ are sealed using a sealing plate 57.

[0065] A sealing plate 57 may be used and installed in any embodiment disclosed herein.

[0066] Likewise, the blocking elements 5, 5’, 5”, 5”’ disclosed and illustrated herein may be used and embodiment prior to or after a corresponding vacuum collecting compartment of a first - 2, 2’, 2”, 2”’ or second vacuum ejector pump 4’, 4”, 4”’.

[0067] From the figures it further becomes clear that the presented vacuum ejector system is highly modular and can be employed in various configurations.

[0068] As explained feed throughs may be sealed using blocking elements or sealing plates depending on industry needs and requirements, likewise these feedthroughs may be sealed prior to or after a corresponding vacuum collecting compartment of the vacuum ejector pump.

[0069] Figure 7 illustrates a similar curve as figure 1 but this time the change in the curve using the vacuum ejector system 1 according to the invention is shown. Figure 7 illustrates the curve of a conventional multistage vacuum ejector pump indicated with reference number 70. The curve 70 illustrates how the vacuum flow rate continuously decreases the higher vacuum level becomes and thus the higher the negative pressure becomes. As mentioned in the introduction for some application it is desirable to increase the vacuum flow rate at around 20% to 50% vacuum level, which is about at -180mbar to -500mbar and which is indicated by the parenthesis 73 in figure 7. Curve 71 illustrates how the vacuum flow rate can be changed and in particular increased using a vacuum ejector system 1 according to the invention. The configuration of the vacuum ejector system 1 according to figure 5 allows to increase the vacuum flow rate according to the curve 71 and therewith generate substantially higher vacuum flow rates at 20% to 50% vacuum level, which is about -180mbar to -500mbar. The vacuum flow rate can be increased substantially up to 3 times the rate of a common multistage ejector system using the same compressed gas source and thus saving a substantial amount of energy. This improves for example the handling capabilities of porous materials via a robot.

[0070] Figure 8 illustrates a method according to the present disclosure using a vacuum ejector system 1 disclosed herein. The method is related to configuring a modular vacuum ejector system 1 having at least a first vacuum ejector pump 2, 2’ and at least a second vacuum ejector pump 4, 4’, 4”.

[0071] The method is designed for controlling vacuum flow and vacuum level in a modular vacuum ejector system comprising a first vacuum ejector pump 2, 2’ and a second vacuum ejector pump 4, 4’, 4” the first vacuum ejector pump 2, 2’ comprising at least two stages 8, 10, S1 , S2 and the second vacuum ejector pump 4, 4’, 4” comprising at least one stage 16, S1 , the method comprising the steps of:

[0072] - Arranging the first vacuum ejector pump 2, 2’ so that at least one stage 8, 10, S1 , S2 of the first vacuum ejector pump is connectable to at least one stage 16, S1of the second vacuum ejector pump 4, 4’, 4”;

[0073] - Providing matching channels 39 in a vacuum collecting compartment 18 in the second vacuum ejector pump 4, which channels 39 can be connected to feed throughs 42, 44 of the first vacuum ejector pump 2, 2’;

[0074] - Connecting a vacuum collecting compartment 18 of the second vacuum ejector pump 4, 4’, 4” to feed throughs 42, 44, 42’, 44’ of the first vacuum ejector pump 2, 2’ using the channels 39 so that fluid can pass from the vacuum collecting compartment 18 of the second vacuum ejector pump 4, 4’, 4” to vacuum cavities 24, 32 of the first vacuum ejector pump 2, 2’;

[0075] - Adjusting vacuum volume flow rate at different vacuum levels in a vacuum collecting compartment 12 of the first vacuum ejector pump 2, 2’ of the vacuum ejector system using at least one blocking element 5, 5’, 5” capable of sealing of vacuum flow in the channels 39.

[0076] The method may also comprise the step of increasing the vacuum volume flow rate by opening / unplugging or moving the active stages S3, S4 towards the later stages S3, S4 as seen a along a flow direction fd of the highspeed gas stream, as shown in figures 4, 5 or 6.

[0077] The method may further comprise the step of configuring the modular vacuum ejector system 1 so that it can increase the vacuum level output via the vacuum collecting compartment by sealing the later stages S3 and / or S4 of the second vacuum ejector pump 4, 4’, 4” using the blocking elements 5, 5’, 5”. It is to be noted that the 1 , 2, 3 or more of the later stages may be sealed depending on the requirement at hand.

[0078] The modular vacuum ejector system may further comprise blocking elements (not shown) that are designed to be controlled from open to closed or partially closed positions remotely. This means the vacuum flow may be adjusted via a computer without physically positioning the blocking elements. This may also mean that each channel comprises a blocking element that can be remotely or electrically controlled.

[0079] The skilled person understands that various configurations are possible using and directing vacuum flow in the vacuum ejector system and therewith achieve specific vacuum level and vacuum flow rate combinations depending on the requirement of the job at hand. The herein presented system therewith provides a high rate of flexibility while at the same saving energy (compressed gas) and providing a comparably small sized solution in the form of the vacuum ejector system 1 disclosed herein.

[0080] Herein the term vacuum level refers to the negative pressure. A high vacuum level corresponds to a high negative pressure. A low vacuum level corresponds to a comparably low negative pressure. For the purpose of this disclosure the maximum negative pressure that may be achieved at sea level is minus (-) 1013 mbar.

[0081] Further even not shown in the embodiments disclosed herein it is possible to use more than two multistage vacuum ejectors arranged so that at least one stage of the first vacuum ejector pump is connectable to at least one stage of the second vacuum ejector pump and so that at least one stage of the second vacuum ejector pump is connectable to at least one stage of a third vacuum ejector pump and so on. Such a plurality of multistage vacuum ejector systems may even use the same compressed gas source.

Claims

Claims1. A modular vacuum ejector system (1 ) comprising a first vacuum ejector pump (2, 2’, 2”’) having a vacuum collecting compartment (12), an inlet (6) for pressurized gas, a first stage (8) and a second stage (10) arranged in series, each stage (8, 10) comprising at least one ejector nozzle (20) in fluid communication with the inlet (6), at least one expansion nozzle (22, 30) and a vacuum cavity (24, 32), the vacuum cavity (24) of the first stage (8) and the vacuum cavity (32) of the second stage (10) being fluidly connected to the vacuum collecting compartment (12) via feed throughs (42, 44) an outlet of the at least one ejector nozzle (20) of the first stage (8) being directed into the vacuum cavity (24) of the first stage (8) and an inlet of the expansion nozzle (22) of the first stage (8) being arranged in the vacuum cavity (24) of the first stage (8), an outlet of the expansion nozzle (22) of the first stage being arranged in the vacuum cavity (32) of the second stage (10) and an inlet of the expansion nozzle (30) of the second stage (10) being arranged in the vacuum cavity (32) of the second stage (10), whereby between the inlets and outlets of the ejector and expansion nozzles a gap is present, characterized by comprising a second vacuum ejector pump (4, 4’, 4”, 4”’) having an inlet (14) for pressurized gas and a vacuum collecting compartment (18) comprising a channel (39), the channel being designed to connect the vacuum collecting compartment (18) with at least one of the feed throughs (42, 44) of the first vacuum ejector pump (2, 2’, 2”’), a first stage (16) comprising at least one ejector nozzle (36) having an outlet, at least one expansion nozzle (38) having an inlet and a vacuum cavity (40) in which the outlet and inlet are arranged leaving a gap between one another, the vacuum cavity (40) of the second vacuum ejector pump (4, 4’, 4”, 4”’) comprising a feed through (46) for connecting the vacuum cavity (40) to the vacuum collecting compartment (18) of the second vacuum ejector pump (4, 4’, 4”, 4”’) and at least one blocking element (5) being designed to seal the open end of the other of the feed throughs (42) of the first vacuum ejector pump (2, 2’, 2”’).

2. The modular vacuum ejector system according to claim 1 , wherein the second vacuum ejector pump (4, 4’, 4”, 4”’) has at least two stages (16, 19) each of them comprising a vacuum cavity (40, 52) with a feed through (46, 54) into the vacuum collecting compartment (18), the vacuum collecting compartment (18)comprising two channels (39, one for each of the at least two stages (16, 19) the channels (39) being connectable to the feed throughs (42, 44) of the two stages (8, 10) of the first vacuum ejector pump (2, 2’, 2”’) and wherein at least one open end of one of the feed throughs (42) of the first vacuum ejector pump is sealable using the at least one blocking element (5).

3. The modular vacuum ejector system according to any of the previous claims, wherein the first vacuum ejector pump (2, 2’, 2”’) and the second vacuum ejector pump (4, 4’, 4”, 4”’) are arranged so that at least one stage (8, 10) of the first vacuum ejector pump (2, 2’, 2”’) can be connected to at least one stage (16, 19) of the second vacuum ejector pump (4, 4’, 4”, 4”’).

4. The modular vacuum ejector system according to any of the previous claims, wherein the size and therewith the vacuum volume flow rate of the first stage, the second stage and so on of each of the first vacuum ejector pump (2, 2’, 2”’) and the second vacuum ejector pump (4, 4’, 4”, 4”’) continuously increase along a flow direction (fd) of a highspeed gas stream.

5. The modular vacuum ejector system according to any of the previous claims, wherein each of the first vacuum ejector pump (2, 2’, 2”’) and the second vacuum ejector pump (4’, 4”, 4”’) comprise multiple stages (S1 , S2, S3, S4) and wherein any of the stages (S1 , S2, S3, S4) of any of the first - or second vacuum ejector pump can be sealed using a suitable number and type of blocking elements (5, 5’, 5”, 5”’) either prior or after the vacuum collecting compartment (18, 18”) of the second vacuum ejector pump (4’, 4”, 4”’).

6. The modular vacuum ejector system according to any of the previous claims, wherein the inlet (6) for compressed gas of the first vacuum ejector pump (2, 2’, 2””) and / or the inlet (14) for compressed gas of the second vacuum ejector pump (4, 4’, 4”, 4”’) further comprise an inlet valve (23).

7. The modular vacuum ejector system according to any of the previous claims, wherein the vacuum collecting compartment (12, 12’) of the first vacuum ejector pump (2, 2’, 2”’) comprises an inlet or opening (13) for connecting a vacuum hose, a suction cup, a vacuum chamber or the like.

8. A method for controlling vacuum flow and vacuum level in a modular vacuum ejector system comprising a first vacuum ejector pump (2, 2’, 2’”) and a second vacuum ejector pump (4), the first vacuum ejector pump (2, 2’, 2’”) comprising at least two stages (8, 10, S1 , S2) and the second vacuum ejector pump (4, 4’, 4”) comprising at least one stage (16, S1 ), the method comprising the steps of:- Connecting at least one stage (16, S1 ) of a second vacuum ejector pump (4, 4’, 4”, 4’”) to at least one stage (8, 10, S1 , S2) of the first vacuum ejector pump (2, 2’, 2’”)- Connecting a vacuum collecting compartment (18) of the second vacuum ejector pump (4, 4’, 4”, 4’”) via channels (39) to feed throughs (42, 44, 42’, 44’) of the first vacuum ejector pump (2, 2’, 2’”) so that fluid can pass from the vacuum collecting compartment (18) of the second vacuum ejector pump (4, 4’, 4”, 4’”) to vacuum cavities (24, 32) of the first vacuum ejector pump (2, 2’, 2’”) and therewith the vacuum collecting compartment (12) of the first vacuum ejector pump (2, 2’, 2’”); and- Adjusting and guiding vacuum volume flow rate at different vacuum levels in a vacuum collecting compartment (12) of the first vacuum ejector pump (2, 2’) of the vacuum ejector system using at least one blocking element (5, 5’, 5”) capable of sealing off vacuum flow in the channels (39) or feed throughs (42, 44) of the first vacuum ejector pump (2, 2’, 2’”).

9. The method according to the previous claim, wherein the first vacuum ejector pump (2, 2’) and the second vacuum ejector pump (4, 4’, 4”) each comprising a plurality of stages (8, 10, 16, 19, S1 , S2, S3, S4) to further adjust and control the vacuum flow at different vacuum levels by:- Providing a number of blocking elements (5, 5’, 5”, 5’”) of matching types; and- Sealing at least one stage either prior to or after the collecting compartment (18) of the second vacuum ejector pump (4, 4’, 4”, 4’”) using at least one of the number of blocking elements (5, 5’, 5”, 5’”).

10. The method according to the previous claims, wherein the number of provided blocking elements (5, 5’, 5”) match the number of stages (16, 19, S1 , S2, S3, S4) of the second vacuum ejector pump (4, 4’, 4”).

11. The method according to the previous claims, wherein the first vacuum ejector pump (2, 2’) and the second vacuum ejector pump (4, 4’, 4”) share a common gas pressure source.

12. The method according to the previous claims, wherein the stages (8, 10,16, 19, S1 , S2, S3, S4) of both the first vacuum ejector pump (2, 2’) and the second vacuum ejector pump (4, 4’, 4”) increase in size and thus vacuum volume flow capacity, along a flow direction (fd) of the highspeed gas stream.

13. The method according to any of the previous claims, comprising the step of increasing the vacuum volume flow rate of the modular vacuum ejector system by removing blocking elements (5, 5’, 5”) from the channels (39) or feed throughs (42, 44, 42’, 44’) of at least two of the stages (S3, S4) with a greatest size of the second vacuum ejector pump (4, 4’, 4”), which are arranged downstream along a flow direction of the highspeed gas stream, preferably farthest away from an ejector nozzle (20) of the first vacuum ejector pump (2, 2’).

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