Multi-stage vacuum generator

Abstract

Vacuum generator comprising a cluster of multi-stage venturi cells, each having a nozzle securely fixed in an inlet orifice of a first mixer having a first suction orifice, and a second mixer fixed to the first mixer such that the second mixer extends coaxially to the first mixer and is spaced from an outlet orifice of said first mixer to form with it a second suction orifice, characterized in that the first mixers are connected rigidly to each other by a first member extending between the first suction orifices and the outlet orifices of the first mixers so as to form a first sealing surface surrounding said first mixers,and the second mixers are connected rigidly to each other by a second member extending between the inlet and outlet ports of the second mixers so as to form a second sealing surface surrounding said second mixers. FIGURE IN ABRIDGED DIAGRAM: Fig. 2,

Description

Title of the invention: Multi-stage vacuum generator

[0001] The invention relates to a vacuum generator using multi-stage venturi cells, in particular for vacuum handling.

[0002] BACKGROUND OF THE INVENTION

[0003] Multi-stage vacuum generators generally comprise up to four venturi cells mounted in parallel. Each venturi cell comprises, as schematically illustrated in [Fig.l], a nozzle B which is intended to be connected to a compressed air supply circuit and which opens into a first suction chamber C1 and opposite a first mixer ML. The first mixer M1 collects the air coming from the nozzle B which, passing through the first chamber C1, sucks in the air present in said first chamber CL. In the same way, the air coming from the first mixer M1 passes through a second suction chamber C2 and is received by a second mixer M2. The air coming from the second mixer passes through a third suction chamber C3 and is collected by a third mixer M3, the air coming from the third mixer M3 opening into the atmosphere.The second and third chambers C2, C3 are connected to the first chamber Cl through unidirectional valves K2, K3 allowing a maximum vacuum level to be obtained. The suction flow rate of the venturi cell is equal to the sum of the suction flow rates of each stage formed by the suction chambers Cl, C2, C3.

[0004] Such an arrangement thus makes it possible to improve the suction flow rate of the venturi cells while reducing their compressed air consumption.

[0005] Document EP 2 827 004 discloses a three-stage venturi cell of the cartridge type. This comprises a sleeve provided radially with suction orifices and into which are inserted, on one side, a nozzle and on the opposite side, a set of three mixers made in one piece. Non-return valves are arranged between the nozzle and the mixers, opposite the suction orifices.

[0006] If the number of components of such a venturi cell is limited, the inlets of the mixers cannot benefit from fillets, which has the effect of restricting the suction performance of the venturi cell. Furthermore, such an arrangement of the mixers requires a large number of seals to ensure the sealing of each stage on the one hand, and the sealing between the sleeve and the mixers on the other hand, which increases the risk of leaks.

[0007] The valves are also necessarily small in size, and are therefore particularly fragile and sensitive to fouling, which tends to reduce the suction flow rate of the venturi cells. Their installation or replacement can also prove restrictive.

[0008] Also known from document EP 1 064 464 is a three-stage venturi cell in which mixers are tightly secured to one another and have radial slots forming suction orifices. The slots are equipped with non-return valves arranged between the mixers.

[0009] If such a venturi cell has a generally cylindrical body allowing easy insertion into a vacuum pump body, it requires, like that described previously, a large number of seals to ensure sealing between each stage and each mixer.

[0010] Similarly, the valves are necessarily small in size and are therefore particularly fragile and sensitive to fouling, which tends to reduce the suction flow rate of the venturi cells. In addition, replacing them can be restrictive.

[0011] Such cells are also removable, which can be a source of malfunction, particularly when one of the seals or one of the valves is forgotten during reassembly.

[0012] Furthermore, the use of individual venturi cells as described in documents EP 2 827 004 and EP 1 064 464 requires the assembly and disassembly of each of the cells inserted into the pump body, which increases the manufacturing time of the pump, as well as that of its maintenance.

[0013] SUBJECT OF THE INVENTION

[0014] The object of the invention is therefore to propose a multi-stage vacuum generator which at least partially overcomes the aforementioned problems. Summary of the invention

[0015] To this end, a vacuum generator is proposed comprising a cluster of multi-stage venturi cells each comprising a nozzle secured in a sealed manner in an inlet orifice of a first mixer provided with a first suction orifice, and a second mixer fixed to the first mixer in such a way that the second mixer extends coaxially with the first mixer and is spaced from an outlet orifice of said first mixer to form therewith a second suction orifice.

[0016] According to the invention, the first mixers are integrally connected to each other by a first member extending between the first suction orifices and the outlet orifices of the first mixers so as to form a first sealing surface surrounding said first mixers, and the second mixers are integrally connected to each other by a second member extending between inlet orifices and outlet orifices of the second mixers so as to form a second sealing surface surrounding said second mixers.

[0017] Such a cluster makes it possible to limit the number of joints to ensure sealing between each stage, which limits the risks of leakage and malfunction of the vacuum generator 1. What is more, the assembly and disassembly of the venturi cells are made easier, as all the venturi cells are inserted in one piece into the vacuum generator.

[0018] In particular, the venturi cells extend parallel to each other.

[0019] In particular, the venturi cells extend in the same plane.

[0020] In particular, the vacuum generator comprises a first seal and a second seal carried respectively by the first member and the second member.

[0021] Preferably then, the first seal and the second seal are lip seals.

[0022] In particular, each venturi cell further comprises a third mixer fixed to the second mixer so that the third mixer extends coaxially with the second mixer and is spaced from an outlet orifice of said second mixer to form therewith a third suction orifice, the third mixers being connected integrally to each other by a third member extending between inlet orifices and outlet orifices of the third mixers so as to form a third sealing surface surrounding said third mixers. Brief description of the drawings

[0023] The invention will be better understood in light of the following description, which is purely illustrative and non-limiting, and must be read in conjunction with the appended figures, among which:

[0024] [Fig-1] [Fig.l] is a schematic view of a multi-stage venturi cell according to prior art;

[0025] [Fig.2] [Fig.2] is a partial exploded view of a multi-stage vacuum generator according to a particular embodiment of the invention;

[0026] [Fig.3] [Fig.3] is a partial sectional view of the vacuum generator illustrated in [Fig.2] ;

[0027] [Fig.4] [Fig.4] is an exploded view of a multi-stage venturi cell cluster forming part of the vacuum generator illustrated in [Fig.2];

[0028] [Fig.5] [Fig.5] is a sectional view of the multi-stage venturi cell cluster illustrated in [Fig.4];

[0029] [Fig.6] [Fig.6] is an exploded view of a variant of the venturi cell cluster multi-stage illustrated in [Fig.4]; and

[0030] [Fig.7] [Fig.7] is an exploded view of a variant of the multi-vacuum generator floors shown in [Fig.2]. DETAILED DESCRIPTION OF THE INVENTION

[0031] With reference to [Fig.2], a vacuum generator 1 according to the invention comprises a housing 10 in the shape of a rectangular parallelepiped and a cluster 40 of venturi cells housed inside the housing 10.

[0032] The housing 10 comprises a main body 11 comprising a bottom 11.1, two side walls 11.2 having a lower edge connected to a side edge of the bottom 11.1, and a front wall 11.3 having a lower edge connected to a front edge of the bottom 11.1 and side edges connected to front edges of the side walls 11.2. The bottom 11.1 and the side walls 11.2 extend along a longitudinal axis X of the housing 10 and respectively define a lower face 10a and side faces 10b of the housing 10.

[0033] A compressed air supply flange (shown schematically in dotted lines) is fixed to the front wall 11.3 of the body and defines a front face 10c of the housing 10 intended to be connected to a source of pressurized air. A rear face 10d of the housing 10 is defined by a flange for immobilizing the cluster 40 of venturi cells (shown schematically in dotted lines) fixed to the rear of the body 11. A suction flange 20 and an exhaust flange (shown schematically in dotted lines) are fixed to the top of the body 11 and respectively define a first upper face 10e and a second upper face 10f of the housing 10. The suction flange 20 is intended to be connected to an enclosure to be emptied, and the exhaust flange is intended to be connected to the atmosphere. An elastomer membrane 30 is compressed between the body 11 and the suction flange 20 and defines with the latter a vacuum collection chamber V.

[0034] The body 11 further comprises four partitions 12, 13, 14, 15 which are substantially parallel and connect the side walls 11.2 together. The partitions 12, 13, 14, 15 each extend in a plane which is substantially perpendicular to the longitudinal axis X of the housing 10.

[0035] As illustrated in [Fig.3], the first partition 12 defines, with the bottom 11.1, the side walls 11.2 and the front wall 11.3 of the body 11, a compressed air distribution chamber D. The first partition 12 and the second partition 13 define, with the bottom 11.1, the side walls 11.2, the front wall 11.3 and the membrane 30, a first suction chamber A1. The second partition 13 and the third partition 14 define, with the bottom 11.1, the side walls 11.2, the front wall 11.3 and the membrane 30, a second suction chamber A2. The third partition 14 and the fourth partition 15 define, with the bottom 11.1, the side walls 11.2, the front wall 11.3 and the membrane 30, a third suction chamber A3. The fourth partition 15 defines, with the bottom 11.1, the side walls 11.2, the immobilizing flange and the exhaust flange, an exhaust collection chamber E.

[0036] The first suction chamber A1 is in fluid communication with the vacuum collection chamber V via an opening 21 provided in the membrane 30.

[0037] The second suction chamber A2 and the third suction chamber A3 are in fluid communication with the vacuum collection chamber V via two openings provided with non-return valves 22 oriented so as to allow a flow of fluid from the vacuum collection chamber V to the second suction chamber A2 or the third suction chamber A3, and to block it if the direction of flow is reversed.

[0038] The partition 12 is provided with four orifices arranged to divide the compressed air entering the distribution chamber D via the supply flange into four streams, and to seal end portions of the cluster 40 of venturi cells inside the housing 10. The orifices are cylindrical in shape and extend along the longitudinal axis X of the housing, the center of the orifices extending along a transverse axis Y perpendicular to the axis X.

[0039] The partitions 13, 14, 15 delimiting the second and third suction chambers A2, A3 are provided with an orifice 13.1, 14.1, 15.1 arranged to seal intermediate portions of the cluster 40 of venturi cells inside the housing 10. The orifices 13.1, 14.1, 15.1 are coaxial and have an oblong section along a plane perpendicular to the axis X, the orifice 13.1 of the second partition 13 having dimensions slightly smaller than those of the orifice 14.1 of the third partition 14, which are themselves slightly smaller than those of the orifice 15.1 of the fourth partition 15.

[0040] With reference to Figures 4 and 5, the cluster 40 of venturi cells comprises a set of four nozzles 41, a set of four first mixers 42, a set of four second mixers 43 and a set of four third mixers 44.

[0041] The first mixers 42 comprise a tubular body 42.1 delimiting a channel 42.2 opening onto an inlet orifice 42.3 and an outlet orifice 42.4 of the first mixer 42. The outlet orifice 42.4 has a diameter slightly greater than that of the inlet orifice 42.3. The bodies 42.1 are provided with two diametrically opposed radial slots forming first suction orifices 42.5.

[0042] The first mixers 42 extend parallel to the X axis in the XY plane so as to form a first row of mixers. The first mixers 42 are integrally connected to each other by a member 42.6 extending close to the outlet orifices 42.4 and arranged to form a first sealing surface 42.7 of oblong shape surrounding all of the first mixers 42. The first sealing surface 42.7 receives a first lip seal 42.8, here made of elastomeric material, which is intended to cooperate with the orifice 13.1 of the second partition 13 extending inside the housing 10 to ensure a seal between the first and second suction chambers A1, A2 ([Fig.3]). Stiffeners 42.9 extending at the level of the first suction orifices 42.5 of the first mixers 42 connect two by two said first mixers 42 in the XY plane.

[0043] The nozzles 41 are identical and are tightly secured in the inlet orifices 42.3 of the first mixers 42. For this purpose, the nozzles 41 comprise a tubular body 41.1 having an annular external shoulder 41.5 forming a stop for insertion of the nozzle 41 into the inlet orifice 42.3 of the first mixer 42. The body 41.1 delimits a spray channel 41.2 for the circulation of compressed air through the nozzle 4L. The channel 41.2 opens onto an inlet orifice 41.3 and an outlet orifice 41.4 of the nozzle 4L. The outlet orifice 41.4 has a diameter slightly greater than that of the inlet orifice 41.3. The channels 41.2 of the nozzles 41 extend coaxially with the channels 42.2 of the first mixers 42 and open at the level of the first suction orifices 42.5 of said first mixers 42.

[0044] The nozzles 41 have a free end provided with an O-ring 41.6 intended to cooperate with the cylindrical orifices of the first partition 12 to ensure a seal between the distribution chamber D and the first suction chamber A1.

[0045] The second mixers 43 comprise a tubular body 43.1 delimiting a channel 43.2 opening onto an inlet orifice 43.3 and an outlet orifice 43.4 of the second mixer 43. The outlet orifice 43.4 has a diameter slightly greater than that of the inlet orifice 43.3, which is itself slightly greater than that of the outlet orifice 42.4 of the first mixers 42.

[0046] The second mixers 43 extend parallel to the X axis in the XY plane so as to form a second row of mixers. The second mixers 43 are integrally connected to each other by a member 43.6 extending close to the outlet orifices 43.4 and arranged to form a second sealing surface 43.7 of oblong shape surrounding all of the second mixers 43. The second sealing surface 43.7 receives a second lip seal 43.8, here made of elastomeric material, which is intended to cooperate with the orifice 14.1 of the third partition 14 extending inside the housing 10 to ensure sealing between the second and third suction chambers A2, A3 ([Fig. 3]). Stiffeners 43.9 extending near the inlet ports 43.3 of the second mixers 43 connect said second mixers 43 in pairs in the XY plane. The stiffeners 43.9 comprise pads 43.5 arranged to form means for indexing and fixing the second mixers 43 on the first mixers 42 so that the channels 43.2 of the second mixers 43 extend coaxially with the channels 42.2 of the first mixers 42 and so that the inlet orifices 43.3 of the second mixers 43 are spaced from the outlet channels 42.2 of the first mixers 42 to form second suction orifices 46. .

[0047] The third mixers 44 comprise a tubular body 44.1 delimiting a channel 44.2 opening onto an inlet orifice 44.3 and an outlet orifice 44.4 of the second mixer 43. The outlet orifice 44.4 has a diameter slightly greater than that of the inlet orifice 44.3, which is itself slightly greater than that of the outlet orifice 43.4 of the second mixers 43.

[0048] The third mixers 44 extend parallel to the X axis in the XY plane so as to form a third row of mixers. The third mixers 44 are integrally connected to each other by a member 44.6 extending close to the outlet orifices 44.4 and arranged to form a third sealing surface 44.7 of oblong shape surrounding all of the third mixers 44. The third sealing surface 44.7 receives a third lip seal 44.8, here made of elastomeric material, which is intended to cooperate with the orifice 15.1 of the fourth partition 15 extending inside the housing 10 to ensure sealing between the third chambers A3 and the exhaust chamber E ([Fig. 3]). Stiffeners 44.9 extending near the inlet orifices 44.3 of the third mixers 44 connect said third mixers 44 in pairs in the XY plane. The stiffeners 44.9 comprise pads 44.5 arranged to form indexing and fixing means of the third mixers 44 on the second mixers 43 so that the channels 44.2 of the third mixers 44 extend coaxially with the channels 43.2 of the second mixers 43 and so that the inlet orifices 44.3 of the third mixers 44 are spaced from the outlet orifices 43.4 of the second mixers 43 to form third suction orifices 47. .

[0049] An immobilizing arm 45 is securely connected to the frame 44.6 supporting the third mixers 44 and extends along the axis X projecting from the outlet orifices 44.4 of said third mixers 44. The arm 45 comprises at a free end a bearing surface 45.1 intended to be in contact with an internal surface of the immobilizing flange forming the rear face 10d of the housing 10.

[0050] The set of first mixers 42, the set of second mixers 43 and the set of third mixers 44 are assembled in series via the pads 43.5, 44.5 and form with the nozzles 41 the cluster 40 composed of four three-stage venturi cells.

[0051] The cluster 40 of venturi cells is inserted along the X axis inside the housing 10 as far as it will go. The O-rings 41.6 of the nozzles then cooperate with the cylindrical orifices of the first partition 12 and ensure the seal between the distribution chamber D and the first suction chamber A1. At the same time, the lip seals 42.8, 43.8, 44.8 cooperate with the oblong orifices 13.1, 14.1, 15.1 of the partitions 13, 14, 15 and ensure the seal between the suction chambers A1, A2, A3 and the exhaust chamber E. The fixing of the flange immobilization at the rear of the body 11 generates contact between said immobilization flange and the surface 45.1 of the arm 45 of the cluster, and therefore an immobilization in translation along the X axis of the cluster 40 of venturi cells inside the housing 10.

[0052] Such an arrangement of the cluster 40 allows tool-free assembly and disassembly thereof inside the housing. It also facilitates cleaning or replacement of the cluster 40, making the vacuum generator 1 quickly operational.

[0053] [Fig.6] illustrates a cluster 40' of venturi cells which is a variant of cluster 40. Cluster 40' differs from cluster 40 in that it comprises:

[0054] - a set of two first plugs 50 inserted in a sealed manner into the inlet orifices 42.3 of two of the first mixers 42 in place of the corresponding nozzles 41; - a set of two second plugs 51 inserted in a sealed manner into the outlet orifices of said two first mixers 42; - a set of two third plugs 52 inserted in a sealed manner into the outlet orifices of the two second mixers 43 extending opposite said two first mixers 42; and - a set of two fourth plugs 53 inserted in a sealed manner into the outlet orifices of the two third mixers 44 extending opposite said two second mixers 43.

[0055] The plugs 50, 51, 52, 53 prevent any fluid from passing through the channels 42.2, 43.2, 44.2 of the mixers 42, 43, 44 in which said plugs 50, 51, 52, 53 are inserted, so that the cluster 40' is composed only of two multi-stage venturi cells, and not four as is the case for the cluster 40. The plugs 50, 51, 52, 53 thus make it possible to reduce the flow rates sucked and consumed by the vacuum generator 1 by modulating the number of venturi cells.

[0056] [Fig.7] illustrates a vacuum generator 1” which is a variant of the vacuum generator 1. The vacuum generator 1” comprises a cluster 40” which differs from the cluster 40 of the vacuum generator 1 in that it does not comprise third mixers 44. The cluster 40” is made up of the nozzles 41, the set of first mixers 42 and the set of second mixers 43 forming four two-stage venturi cells and not three-stage as is the case for the cluster 40.

[0057] Of course, the invention is not limited to the embodiment described but encompasses any variant falling within the scope of the invention as defined by the claims.

[0058] The number of venturi cells constituting the cluster 40, 40'' may be less than or greater than four.

[0059] The number of mixers constituting the venturi cells can be equal to one or be greater than three.

[0060] The number of mixers clogged by plugs may be less than or greater than two.

[0061] Although the mixers of each set extend here in the same plane forming a row, they can also extend in different planes to, for example, form a double row of superimposed mixers or be arranged so as to form a cylinder.

[0062] Advantageously, the inlet orifices of the mixers can be provided, as illustrated in Figures 3 to 5, with a fillet making it possible to improve the suction performance of the venturi cells.

[0063] Advantageously again, the indexing pads 43.5, 44.5 of the sets of mixers can be arranged, as illustrated in FIGS. 3 to 5, to form poka-yoke type keying devices making it possible in particular to avoid assembling the third mixers with the first mixers.

[0064] The members of the sets of mixers 42, 43, 44, and more particularly the associated sealing surfaces 42.7, 43.7, 43.7, may have a shape different from that illustrated in the various figures: circular, rectangular, ovoid, etc.

[0065] Although the lip seals 42.8, 43.8, 44.8 are here carried by the members of the mixer sets 42, 43, 44, they can also be carried by the cylindrical orifices of the partitions 13, 14, 15.

[0066] Although the seals 42.8, 43.8, 44.8 are lip seals here, they can be of a different nature: toric...

Claims

Claims

1. Vacuum generator (1, 1”) comprising a cluster (40, 40', 40”) of multi-stage venturi cells each comprising a nozzle (41) secured in a sealed manner in an inlet orifice (42.3) of a first mixer (42) provided with a first suction orifice (42.5), and a second mixer (43) fixed to the first mixer so that the second mixer extends coaxially with the first mixer and is spaced from an outlet orifice (42.4) of said first mixer to form therewith a second suction orifice (46), characterized in that the first mixers are connected integrally to each other by a first member (42.6) extending between the first suction orifices and the outlet orifices of the first mixers so as to form a first sealing surface surrounding said first mixers, and the second mixers are connected together by a second member (43.6) extending between inlet ports and outlet ports of the second mixers so as to form a second sealing surface surrounding said second mixers.

2. A vacuum generator (1, 1”) according to claim 1, wherein the venturi cells extend parallel to each other.

3. Vacuum generator (1, 1”) according to claim 2, in which the venturi cells extend in the same plane (XY).

4. A vacuum generator (1, 1”) according to any preceding claim, comprising a first seal (42.8) and a second seal (43.8) carried respectively by the first member (42.6) and the second member (43.6).

5. A vacuum generator (1, 1”) according to claim 4, wherein the first seal (42.8) and the second seal (43.8) are lip seals.

6. Vacuum generator (1, 1”) according to claim 4 or 5, comprising a housing (10) in which the cluster (40, 40', 40”) of venturi cells is inserted, the housing (10) comprising partitions (13, 14) delimiting chambers (A1, A2, A3) provided with orifices (13.1, 14.1, 15.1) which are crossed by said cluster, the first seal (42.8) and the second seal (43.8) ensuring the seal between the chambers.

7. A vacuum generator (1) according to any preceding claim, wherein each venturi cell of the cluster (40, 40') further comprises a third mixer (44) attached to the second mixer (43) so that the third mixer extends coaxially with the second mixer and is spaced from an outlet orifice (43.4) of said second mixer to form therewith a third suction orifice (47), the third mixers being integrally connected to each other by a third member (44.6) extending between inlet orifices and outlet orifices of the third mixers so as to form a third sealing surface surrounding said third mixers.

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