Membrane pump

Abstract

A membrane pump comprises: a main body (2) defining at least one cavity (20a, 20b); at least one flexible membrane (3a, 3b) to define a variable-volume pumping chamber with the cavity; and driving members. Said driving members comprise: a motor (6) having a rotor (60) configured to be rotated around a rotation axis (R-R); a piston (7) kinematically connected to each flexible membrane (3a, 3b) to control the deformation thereof, the piston (7) being slidably along a driving direction (X-X) so as to vary the volume of each pumping chamber; and transmission elements (8) configured to kinematically connect the rotor (60) to the piston (7). Said transmission elements comprise: a first cam (26) and a second cam (27) spaced apart along the driving direction (X-X), and a first cam follower (81a) and a second cam follower (81b) integral along the driving direction (X-X) and operatively associated with the first cam (80a) and the second cam (80b), respectively; wherein upon rotation of the rotor (60) around the rotation axis (R-R), the first cam (80a) and the second cam (80b) are configured to alternately act respectively on the first cam follower (81a) and on the second cam follower (81b) to move said first and second cam followers (81a, 81b) in opposite moving orientations (V1, V2) along the driving direction (X-X).

Description

[0001] Title: “Membrane pump”

[0002] DESCRIPTION

[0003] Technical Field

[0004] The present invention relates to a membrane pump that can be used for pumping fluids, even at high density or with abrasive particles in suspension.

[0005] The pump which is the subject of the present invention finds application in various fields of the art such as, for example, in the chemical industry for pumping paints, plasters, creams or gelatins, in the ceramic industry for pumping ceramic slip, in the textile industry for pumping adhesives, latices, inks, in the food industry for pumping fruit and vegetable pulps, sugar solutions, animal offal as well as in ecology for pumping lime, heavy sludge and the like.

[0006] State of the art

[0007] Several types of membrane pumps - i.e., vacuum pumps employing an elastically deformable diaphragm to pump a fluid from a supply duct to a delivery duct - have been developed over the years.

[0008] A first known type of membrane pump uses compressed air which, through appropriate exchange valves, alternately drives two opposite membranes.

[0009] This first type of membrane pump requires the presence of air compressors of somewhat high power for the supply of compressed air with somewhat modest overall system efficiencies. Furthermore, this type of pump only allows to achieve heads compatible with the maximum air pressures available through the compressor.

[0010] To overcome the limits of the membrane pumps described above, it was thought to replace the disadvantageous compressed air with a driving liquid flow pressurized by a piston motor. However, while allowing to achieve higher heads than those of compressed air driven pumps, the use of the driving liquid significantly complicates the architecture of the pumps, significantly increasing the cost thereof.

[0011] Electrically driven diaphragm pumps have also been developed. In this type of pump, the membranes are driven by a piston moved by linear reciprocating motion by a linear electric motor or by a rotary electric motor kinematically connected to the piston by means of a recirculating ball screw transmission. Examples of the latter type of membrane pumps are described in EP1515044A1 and US2022074402A1.

[0012] However, it should be noted that even the known electrically driven diaphragm pumps are not without drawbacks. In fact, linear motors are very expensive while rotary motors associated with a recirculating ball transmission operate continuously in start-up conditions and, therefore, exhibit high energy consumption and limited dynamic behaviour.

[0013] In this regard, with reference to the solution described in US2022074402A1, it should be noted that the kinematic mechanism of the ball recirculation transmission necessarily requires the motor to rotate the rotor alternately in opposite rotation directions (i.e., clockwise and counterclockwise) to move the linear reciprocating motion piston. Given the limited stroke of the piston, the motor is required to reverse the rotation direction of the rotor at high rates. This means that the motor works continuously in the starting position, that is, in the operating condition with the worst energy efficiency.

[0014] It should also be noted that the recirculation kinematic mechanism of balls, requiring frequent reversals of motion, introduces a certain degree of complexity in the pump, not only in terms of construction but also in terms of control. In fact, to ensure the accurate reversal of the piston's motion, the pump must be equipped with expensive precision encoders and sophisticated control electronics.

[0015] Finally, it is also noted that the recirculation kinematic mechanism of balls limits the maximum operating frequency of the pump since the motor is continuously required to overcome not only the inertial force of the piston but also that of the rotor to reverse its rotation direction.

[0016] Object of the invention

[0017] In this context, the technical task underlying the present invention is to propose a membrane pump which overcomes the drawbacks of the prior art mentioned above.

[0018] In particular, an object of the present invention is to provide a membrane pump with high energy efficiency.

[0019] It is also an object of the present invention to provide a membrane pump with simple and low-cost construction and control.

[0020] A further object of the present invention is to provide a membrane pump capable of exceeding the maximum operating dynamics of known membrane pumps.

[0021] Another object of the present invention is to provide a membrane pump that does not require frequent maintenance interventions in order to operate correctly.

[0022] SUMMARY OF THE INVENTION

[0023] The technical task mentioned and the objects specified are substantially achieved by a membrane pump in accordance with one or more of the appended claims.

[0024] In particular, the present invention proposes to provide a membrane pump driven by a rotary electric motor in which the piston is kinematically connected to the latter by means of transmission elements comprising a pair of cams and a pair of cam folllowers, respectively mounted on the rotor of the motor and on the piston (or vice versa).

[0025] In use, upon rotation of the rotor around the respective rotation axis, the pair of cams are configured to alternately act on the respective cam followers to move them in reciprocating motion in opposite moving orientations along the driving direction.

[0026] It should be noted that such cam transmission elements, unlike screw elements with ball recirculation, allow to move the linear reciprocating motion piston by rotating the rotor always in the same rotation direction.

[0027] The unidirectional rotation of the rotor has considerable advantages, especially from the point of view of energy consumption. In use, downstream of the natural ignition transient, the pump which is the subject of the present invention works with the motor in the regime operating state in which, as is known, it has higher energy efficiency with respect to the start-up.

[0028] The unidirectional rotation of the rotor also allows to reduce the heating, and therefore the thermal dissipation, of the motor because, unlike what happens in known membrane pumps, it does not have to continuously stop the rotor to reverse the rotation direction thereof with strong accelerations.

[0029] It is therefore evident that the present invention makes it possible to provide a high-efficiency membrane pump having lower energy consumption than membrane pumps known in the state of the art.

[0030] The unidirectional rotation of the rotor, not requiring to continuously overcome the inertia force of the rotor to reverse the rotation direction thereof, also allows to improve the operating dynamics and, therefore, the maximum head of the pump.

[0031] It should also be noted that the pump which is the subject of the present invention, not having to handle frequent inversions of the rotation direction of the rotor, allows to simplify and reduce the cost of the electronic control equipment used to control the operation of the motor.

[0032] It should also be noted that the use of a pair of cam followers allows to reduce the phenomena of wear, as each of these works for half the rotation of the rotor. Thereby, the frequency of maintenance interventions is reduced, with a consequent reduction in the downtime of the pump.

[0033] LIST OF FIGURES

[0034] Further features and advantages of the present invention will become more apparent from the indicative, and therefore non-limiting, description of a membrane pump as illustrated in the appended drawings, in which:

[0035] - Figure 1 shows a perspective view of a membrane pump according to the present invention,

[0036] - Figure 2 shows an exploded view of some components of the pump of Figure 1;

[0037] - Figure 3 shows a lateral sectional view of the pump of Figure 1 to better show some internal construction details thereof;

[0038] - Figure 4 shows a sectional perspective view of the pump of Figure 1 to better show some internal construction details;

[0039] - Figure 5 shows a perspective view of the pump of Figure 1 with some parts removed to better illustrate others thereof;

[0040] - Figures 6a and 6b respectively a show first and a second embodiment of the development of the profile of the cams of the pump of Figure 1.

[0041] DETAILED DESCRIPTION

[0042] With reference to the attached figures, the present invention relates to a pump 1 for fluids, in particular liquids (also with high density or with abrasive particles in suspension), of the membrane type.

[0043] It should be specified that in the context of the present invention, "membrane pump" is intended to indicate a type of vacuum pump in which the pumping action is carried out by means of the elastic deformation of one or more membranes / diaphragms placed to close the respective variable-volume pumping chambers.

[0044] The pump 1 comprises a main body 2 defining at least one cavity 20a, 20b configured to receive a fluid to be pumped.

[0045] In particular, in the embodiment shown in Figure 3, the main body 2 defines two cavities 20a, 20b opposite each other.

[0046] According to an aspect, the main body 2 comprises two hollow bodies 2a, 2b defining a respective cavity 20a, 20b and connected by an intermediate tubular body 2c that keeps them spaced apart, defining a seat 2d therebetween. One or both of the hollow bodies 2a, 2b may be indifferently integrally formed or not with the intermediate tubular body 2c.

[0047] Each of the aforesaid cavities 20a, 20b is provided with an inlet la, lb (suction opening) and an outlet Ua, Ub (delivery opening) respectively configured to allow the supply and discharge of the fluid into / from the respective cavity 20a, 20b.

[0048] If the main body 2 has two cavities 20a, 20b, the respective inlets la, lb and outlets of the cavities 20a, 20b can be fluid-dynamically connected by a supply duct Ci and a delivery duct Cu.

[0049] It should be specified that each inlet la, lb and outlet Ua, Ub is equipped with a non-return valve V configured to prevent the reflux of the fluid and therefore ensure that, during the operation of the pump 1, the fluid passes through the cavity 20a, 20b from the inlet la, lb towards the outlet Ua, Ub and not vice versa.

[0050] According to an aspect, each cavity 20a, 20b is identified by a concave wall on which the inlet la, lb and the outlet Ua, Ub are made. Preferably, said concave wall of each cavity 20a, 20b is directed transverse to what will hereinafter be defined as driving direction X-X.

[0051] The pump 1 further comprises at least one flexible membrane 3a, 3b (hereinafter also "membrane 3a, 3b") mounted on the main body 2 so as to be associated with a respective cavity 20a, 20b and define a variable-volume pumping chamber 4a, 4b therewith.

[0052] According to an aspect, each pumping chamber 4a, 4b is delimited by opposite parts, in particular along what will hereinafter be defined as driving direction X-X, by a respective cavity 20a, 20b and by a respective membrane 3a, 3b. More precisely, each pumping chamber 4a, 4b is delimited by opposite parts by the respective membrane 3a, 3b and by the concave wall that identifies the respective cavity 20a, 2b.

[0053] It should be specified that each membrane 3a, 3b is hermetically mounted on the main body 2 so as to prevent leakage of fluid from the respective pumping chamber 4a, 4b. In this respect, gaskets or other known sealing means may be employed.

[0054] It should also be specified that each membrane 3a, 3b is made of an elastically deformable material adapted to come into direct contact with the fluid to be pumped.

[0055] In use, to pump the fluid from the inlet la, lb to the outlet Ua, Ub, the flexible membrane 3a, 3b is cyclically deformed to and from the respective cavity 20a, 20b thus repeatedly increasing and decreasing the volume of the respective pumping chamber 4a, 4b. The displacemente of the membrane 3a, 3b from the respective cavity 20a, 20b involves an expansion of the pumping chamber 4a, 4b and therefore a suction effect that draws the liquid from the inlet la, lb, while the approach of the membrane 3 a, 3b to the respective cavity 20a, 20b causes a contraction of the pumping chamber and therefore the delivery of the fluid under pressure through the outlet Ua, Ub. Therefore, the cyclical variations in the volume of each pumping chamber 4a, 4b between a minimum volume and a maximum volume generate a flow Fa, Fb that flows through the respective cavity 20a, 20b from the inlet opening la, lb to the outlet opening Ua, Ub.

[0056] According to an aspect, each membrane 3a, 3b has a central portion 30a, 30b movable to and from the respective cavity 20a, 20b and a peripheral edge 31a, 31b mounted on the main body 2 so as to hermetically close said cavity 20a, 20b. Preferably, each membrane 3a, 3b mainly extends transverse to what will hereinafter be defined as the driving direction X-X between the peripheral edge 3 la, 3 lb and the central portion 30a, 30b.

[0057] In the embodiment shown in Figure 3, the pump 1 comprises two flexible membranes 3a, 3b defining respective pumping chambers 4a, 4b with the cavities 20a, 20b to which they are associated. Preferably, the two cavities 20a, 20b and the respective membranes 3a, 3b are geometrically equal but mirrored with respect to a midplane A-A of the main body 2 and, therefore, to the aforesaid seat 2d defined by the latter.

[0058] The pump 1 further comprises driving members 5 configured to act on the one or more flexible membranes 3a, 3b so as to elastically deform them and cyclically vary the volume of the respective pumping chambers 4a, 4b between a minimum volume and a maximum volume. In accordance with the above, the repeated compression and expansion cycles of each pumping chamber 4a, 4b generate the delivery of a flow Fa, Fb under pressure from the respective outlet Ua, Ub.

[0059] The driving members 5 are mounted on the main body 5. In particular, in the embodiment of Figure 3, the driving members 5 are arranged in the seat 2d in interposition between the hollow bodies 2a, 2b of the main body 2 and, therefore, between the two flexible membranes 3a, 3b.

[0060] As shown in the attached figures, the driving members 5 comprise a motor 6 mounted on the main body 2 and having a rotor 60 configured to be rotated around a rotation axis R-R.

[0061] The motor 6 also comprises a stator 61 which, preferably, is fixed to the main body 2 and, in particular, to the intermediate tubular body 2c.

[0062] According to a further aspect, the rotor 60 has a hollow cylindrical conformation so as to be able to house further components of the driving members 5 therein. Preferably, the rotor 60 defines a channel 60a having the rotation axis R-R as its axis.

[0063] The driving members 5 further comprise a piston 7 kinematically connected to each flexible membrane 3a, 3b and slidably mounted on the main body 2 along a driving direction X-X which, preferably, extends along the rotation axis R-R - i.e., preferably, the rotation axis R-R and the driving direction X-X are coincident.

[0064] In use, the movement of the piston 7 along the driving direction X-X causes the deformation of the one or more flexible membranes 3a, 3b to which it is connected and, therefore, a volumetric variation of the respective pumping chambers 4a, 4b. In other words, the movement of the piston 7 along the driving direction X-X commands the expansion / contraction of each pumping chamber 4a, 4b.

[0065] Preferably, the piston 7 is fixed to the central portion 30a, 30b of each membrane 3a, 3b along the driving direction X-X. In doing so, the movement of the piston 7 deforms the membrane 3 a, 3b, moving the central portion 30a, 30b thereof with respect to the peripheral edge 3 la, 3 lb along the driving direction X-X.

[0066] According to an aspect, the piston 7 is arranged inside the channel 60a of the rotor 60 so as to be able to slide with respect to the main body 2 along the driving direction X-X. In particular, preferably, the piston 7 is arranged coaxially to the channel 60a.

[0067] In the embodiment of Figure 3, the piston 7 mainly extends along the driving direction X-X between two end portions 71, 72, each of which is fixed to a respective flexible membrane 3a, 3b. In doing so, by moving along the driving direction X-X, the piston 7 simultaneously deforms both flexible membranes 3a, 3b, varying the volume of the respective pumping chambers 4a, 4b in the opposite manner (i.e. when one pumping chamber expands the other compresses and vice versa).

[0068] According to an aspect, the main body 2 comprises a support element 50 configured to support the piston 7 transverse to the driving direction X-X. In detail, the support element 50 is provided with a guide portion 50a in which a sliding portion 70 of the piston 7 is slidably mounted so as to be able to move along the driving direction X-X.

[0069] Preferably, the guide portion 50a of the support element 50 and the sliding portion 70 of the piston 7 have a conformation adapted to prevent the rotation of the piston 7 around the rotation axis R-R with respect to the main body 2. This allows to deform each membrane 3 a, 3b only along the driving direction X-X and prevent it from being torsionally loaded around the latter direction. The absence of torsional deformation of the membranes 3a, 3b increases their useful life, thus reducing the frequency of inconvenient maintenance operations to the benefit of the operating costs of the pump 1.

[0070] In the embodiment shown in Figures 2 and 4, the sliding portion 70 of the piston 7 has a pair of rods 70a, 70b extending parallel to the driving direction X-X and at least one of which, preferably both, are offset with respect to the rotation axis R-R. In this embodiment, the guide portion has a pair of through holes in which the respective rods 70a, 70b are slidably housed along the driving direction X-X.

[0071] In alternative embodiments to that shown in Figures 2 and 4, the sliding portion 7 can also have an eccentric portion or a non-axially symmetric geometry with respect to the rotation axis R-R which, by engaging in the complementarily shaped guide portion 50a, prevents the rotation of the piston 7.

[0072] Preferably, the main body 2 comprises a pair of support elements 50 spaced apart along the driving direction X-X arranged, for example, in opposite portions of the seat 2d at a respective membrane 3a, 3b.

[0073] Furthermore, preferably, each support element 50 also has an abutment wall 51 configured to engage the peripheral edge 3 la, 3 lb with a respective membrane 3a, 3b to fix the position thereof along the driving direction X-X. Even more preferably, the peripheral edge 31a, 3b of each membrane 3a, 3b is interposed between a respective abutment wall 51 and a respective hollow body 2a, 2b so as to be retained by opposite parts along the driving direction X-X.

[0074] As shown in the following figures, the driving members 5 further comprise transmission elements 8 configured to kinematically connect the rotor 60 to the piston

[0075] 7 so as to move the piston 7 in reciprocating motion along the driving direction X-X upon rotation of the rotor 60 around the rotation axis R-R.

[0076] According to an aspect, in the double-membrane embodiment, the transmission elements 8 are interposed between the two membranes 3a, 3b along the driving direction X-X. For example, in the embodiment of Figure 3, the transmission elements

[0077] 8 are arranged in the seat 2d defined between the two hollow bodies 2a, 2b, in particular, but not necessarily, within the channel 60a of the rotor 60.

[0078] The transmission elements 8 comprise first and second cams 80a, 80b spaced along the driving direction X-X and at least one cam follower 81a, 81b interposed between the first and the second cam 80a, 80b along the driving direction X-X. In use, upon rotation of the rotor 60 around the rotation axis R-R in a single rotation direction (clockwise or counter-clockwise only), the first and the second cam 80b are configured to alternately act on the at least one cam follower 81a, 81b to move said at least one cam follower 81a, 81b in opposite moving orientations (senses) VI, V2 along the driving direction X-X.

[0079] With reference to the preferred embodiment shown in Figures 2-6, it should be noted that the transmission elements 8 preferably comprise two cam followers 81a, 81b, each of which is operatively associated with a respective cam 80a, 80b. More details on this preferred embodiment and the respective technical advantages will be provided in a subsequent part of the description. The first and the second cam 80a, 80b have a conformation such as to alternately push the at least one cam follower 81a, 81b in a respective moving orientation VI, V2 along the driving direction X-X upon rotation of the rotor 60 around the rotation axis R-R in a single rotation direction (clockwise or counter-clockwise only). For example, as shown in Figures 6a and 6b, the first and the second cam 80a, 80b can have a sinusoidal or triangular wave profile (curve with constant slope sections).

[0080] As can be seen from the embodiments described below, the cams 80a, 80b and the at least one cam follower 81a, 81b can be respectively mounted (fixed) on the rotor 60 and on the piston 7, or vice versa.

[0081] In a first embodiment, the cams 80a, 80b are mounted on the rotor 60 so as to be integral with the latter around the rotation axis R-R and along the driving direction X- X, while the at least one cam follower 81a, 81b is mounted on the piston 7 so as to be integral with the latter along the driving direction X-X. In this embodiment, the cams rotate around the rotation axis R-R with the rotor 60.

[0082] Otherwise, in a second embodiment not shown in the attached figures, the cam follower 81a, 81b is mounted on the rotor 60 so as to be integral with the latter around the rotation axis R-R and along the driving direction X-X, while the at least one cam 80a, 80b is mounted on the piston 7 so as to be integrally movable with the latter along the driving direction X-X.

[0083] In an alternative embodiment to that shown in the attached figures, the transmission elements 8 comprise a body having an annular groove in which its opposite sides identify the first and the second cam 80a, 80b and in which the cam follower is slidably mounted so as to assume different positions along the driving direction X-X upon rotation of said body (drum cam).

[0084] According to an aspect, the first and the second cam 80a, 80b and the at least one cam follower 81a, 81b make a desmodromic kinematic mechanism and, in particular, an alternating linear kinematic mechanism of the frontal type with doublecam and positive control force. In this regard, it should be specified that with the adjective "frontal" it is meant that each cam follower engages with the cams along the driving direction X-X, while with "positive control" it is meant that each cam is configured to control the movement of the cam follower(s) in a respective direction along the driving direction X-X.

[0085] In the embodiments shown in the attached figures, each cam 80a, 80b has a track 82a, 82b extending around the rotation axis R-R and on which the respective cam follower 81a, 81b is configured to slide upon movement of the rotor 60 around the rotation axis R-R. Therefore, when the motor 6 is activated, the cam follower 81a, 81b and the respective track 82a, 82b perform a respective rotary motion around the rotation axis R-R.

[0086] Preferably, the track 82a, 82b of each cam 80a, 80b extends continuously around the rotation axis R-R between a maximum Max and a minimum Min spaced along the driving direction X-X. In use, upon rotation of the rotor 60 around the rotation axis R- R, the at least one cam follower 81a, 82a slides along the track 82a, 82b of each cam 80a, 80b following the trend along the driving direction X-X and thus oscillating between two opposite dead points respectively corresponding to the maximum Max and the minimum Min of the track 82a, 82b.

[0087] In the embodiment of Figures 3 and 4, each cam 80a, 80b has a central through hole 83a, 83b extending along the driving direction X-X and around which the respective track 82a, 82b extends. Preferably, the central through hole 83a, 83b has the rotation axis R-R as an axis.

[0088] Still with reference to the embodiment of Figures 3 and 4, the piston 7 is slidably arranged inside the central hole 83 a, 83b of each cam 80a, 80b so as to be able to move along the driving direction X-X. As shown in Figure 4, preferably, the at least one cam follower 81a, 81b projects from the piston 7 on which it is mounted along a direction transverse to the driving direction X-X to abut against the track 82a, 82b of each cam 80a, 80b along the driving direction X-X.

[0089] According to an aspect, the tracks 82a, 82b of the aforesaid first and second cams 80a, 80b are equal, opposite each other along the driving direction X-X, and oriented around the rotation axis R-R so as to have the respective maximums Max and minimums Min aligned. The at least one cam follower 81a, 8b is interposed between the tracks 82a, 82b of the first and second cams 80a, 80b with which it is on opposite sides in contact.

[0090] According to a preferred embodiment shown in Figures 2-6, the transmission elements 8 comprise a first cam follower 81a and a second cam follower 81b integrally movable along the driving direction X-X and each of which is operatively associated with a respective cam 80a, 80b. In use, upon rotation of the rotor 60 around the rotation axis R-R in a single rotation direction (clockwise or counter-clockwise only), the first and the second cam 80a, 80b are configured to alternately act on the first and second cam followers 81a, 81b, respectively, to move them together in a respective moving orientation VI, V2 along the driving direction X-X. That is to say that, during a rotation of the rotor 60, for a half-turn the first cam 80a acts on the first cam follower 81a to push it in a first orientation VI along the driving direction X-X and for the next half-turn the second cam 80b acts on the second cam follower 8 lb to push it in a second orientation V2 opposite the first VI along the driving direction X-X.

[0091] It should be noted that the use of two distinct cam followers 81a, 81b allows to reduce their wear rate since, as can be seen from the above, each of them only works a half-turn of the rotor 60. This is particularly advantageous since it allows the frequency of maintenance interventions and therefore pump downtime to be decreased. Preferably, with reference to Figure 4, each cam follower 80a, 80b has a roller R configured to slide / rotate on the respective cam 80a, 80b upon rotation of the rotor 60 around the rotation axis R-R. The use of the roller R on board each cam follower 80a, 80b allows to exploit the rolling friction instead of the much more aggressive sliding friction and, therefore, reduce the phenomena of wear.

[0092] In use, the rollers R of the first and second cam followers 80a, 80b rotate in the opposite direction (one clockwise and the other counter-clockwise), so as to correctly follow the profile of the respective cams 80a, 80b.

[0093] It is important to note that, in the presence of only one cam follower, the roller R would be forced to instantly reverse its rotation direction in the passage from one cam to the other 80a, 80b. Such a sudden reversal is physically impossible and, consequently, the use of a single cam follower would result in inevitable rubbing between the roller R and the cams 80a, 80b, with a rapid deterioration of both components.

[0094] It should be specified that the roller R of each cam follower 81a, 81b is in an idle state, so that it can freely roll on the cam 80a, 80b with which it is associated upon the driving of the rotor 60.

[0095] In detail, preferably, each cam follower 81a, 81b comprises a pin P extending radially to the rotation axis R-R on which the roller R is mounted idle so as to be able to freely rotate around the main extension direction of said pin P.

[0096] In the embodiment of Figure 4, the pin P is fixed to the piston 7 so as to be integrally movable with the latter along the driving direction X-X.

[0097] With reference to the attached figures, it should be noted that the rotor 60 is mounted on the main body 2 by means of a first and a second group of bearings 9a, 9b arranged at its opposite ends 60b.

[0098] The first and second group of bearings 9a, 9b have the function of retaining the rotor 60 along the driving direction X-X while allowing the free rotation thereof around the rotation axis R-R with respect to the main body 2. In this regard, it should be specified that, in order to prevent malfunctions and damage to the motor 6, it is essential that the rotor 60 does not have mechanical clearance with the main body 2 along the driving direction X-X. Therefore, the choice of the type of bearings used takes on particular importance.

[0099] According to a preferred embodiment shown in Figure 3, the first group of bearings 9a comprises a pair of opposite ball bearings or oblique roller bearings 90a, 91a, while the second group of bearings 9b comprises a radial bearing 90b. This embodiment is preferable as it allows to both withstand high loads along the driving direction X-X and to securely fix the rotor 60 to the main body 2 along the latter direction so as to prevent the onset of mechanical clearance.

[0100] According to an aspect, the driving members 5 further comprise a driver 10 configured to supply line current to the motor 6 and rotate the rotor 60 around the rotation axis R-R in a single rotation direction.

[0101] Preferably, the driver 10 allows the user to control the angular speed of the rotor 60 and, therefore, the frequency of oscillations of the piston 7 along the driving direction X-X that determines the flow rate of the pumped fluid of the pump 1. The driver can for example comprise a knob 10a for adjusting the angular speed of the motor from 0 to a maximum speed.

[0102] The driver 10 can be mounted on board the main body 2 or arranged outside it, the important thing is that it is electrically connected to the motor 6.

[0103] Clearly, in order to satisfy contingent and specific needs, a person skilled in the art may make numerous modifications and variants to the configurations described above. Such variants and modifications are however all contained within the scope of protection of the invention as defined by the following claims.

Claims

CLAIMS1. A membrane pump (1) for fluids, comprising:- a main body (2) defining at least one cavity (20a, 20b) configured to receive a fluid to be pumped, each cavity (20a, 20b) being provided with an inlet (la, lb) for supplying the fluid into the respective cavity (20a, 20b) and an outlet (Ua, Ub) for discharging the fluid from the respective cavity (20a, 20b);- at least one flexible membrane (3 a, 3b) mounted on the main body (2) so as to define a variable-volume pumping chamber (4a, 4b) with the cavity (20a, 20b) to which it is functionally associated,- driving members (5) comprising:- a motor (6) mounted on the main body (2) and having a rotor (60) configured to be rotated around a rotation axis (R-R);- a piston (7) kinematically connected to each flexible membrane (3a, 3b) to control the deformation thereof, the piston (7) being slidably mounted on the main body (2) along a driving direction (X-X) so as to vary the volume of each pumping chamber (4a, 4b) by deforming the respective flexible membrane (3a, 3b) and pump the fluid from the inlet (la, lb) to the outlet (Ua, Ub);- transmission elements (8) configured to kinematically connect the rotor (60) of the motor (6) to the piston (7) so as to move the piston (7) in reciprocating motion along the driving direction (X-X) upon rotation of the rotor (60) around the rotation axis (R-R), said transmission elements (8) comprising a first cam (80a) and a second cam (80b) spaced apart along the driving direction (X-X) and at least one cam follower (81a, 81b) interposed between the first cam (80a) and the second cam (80b) along the driving direction (X-X), the cams (80a, 80b) and the at least one cam follower (81a, 81b) being respectively mounted on the rotor (60) and on the piston (7), or vice versa, characterized in that:- the transmission elements (8) comprise a first cam follower (81a) and a second cam follower (81b) integral along the driving direction (X-X) and operatively associated with the first cam (80a) and the second cam (80b), respectively,- upon rotation of the rotor (60) around the rotation axis (R-R), the first cam (80a) and the second cam (80b) are configured to alternately act respectively on the first cam follower (81a) and on the second cam follower (81b) to move said first and second cam follower (81a, 81b) in opposite moving orientations (VI, V2) along the driving direction (X-X).

2. Pump (1) according to claim 1, wherein the first cam (80a), the second cam (80b), and the first and second cam followers (81a, 81b) make a desmodromic kinematic mechanism.

3. Pump (1) according to any one of the preceding claims, wherein:- the rotation axis (R-R) coincides with the driving direction (X-X);- each cam (80a, 80b) has a track (82a, 82b) extending around the rotation axis (R-R) and on which the respective cam follower (81a, 81b) is configured to slide upon movement of the rotor (60) around the rotation axis (R-R).

4. Pump (1) according to claim 3, wherein the track (82a, 82b) of each cam (80a, 80b) extends continuously around the rotation axis (R-R) between a maximum (Max) and a minimum (Min) spaced along the driving direction (X-X).

5. Pump (1) according to any one of the preceding claims, wherein each cam follower (81a, 81b) has a roller (R) configured to slide while rotating on the respective cam (80a, 80b) upon rotation of the rotor (60) around the rotation axis (R-R).

6. Pump (1) according to any one of the preceding claims, wherein:- the flexible membrane (3a, 3b) mainly extends transverse to the driving direction (X- X) between a central portion (30a, 30b) and a peripheral edge (3 la, 3 lb);- the peripheral edge (3 la, 3 lb) of each flexible membrane (3a, 3b) is mounted on the main body (2) so as to hermetically close the respective cavity (20a. 20b);- the central portion (30a, 30b) of each flexible membrane (3a, 3b) is fixed to the piston (7) along the driving direction (X-X).

7. Pump (1) according to any one of the preceding claims, wherein:- each cam (80a, 80b) is mounted on the rotor (60) so as to be rotationally integral with the rotator (60) around the rotation axis (R-R);- the at least one cam follower (81a, 81b) is mounted on the piston (7) so as to be integrally movable with the piston (7) along the driving direction (X-X).

8. Pump (1) according to any one of the preceding claims, wherein:- the main body (2) comprises a support element (50) configured to support the piston (7) transverse to the driving direction (X-X), said support element (50) having a guide portion (50a) in which the piston (7) is slidably mounted along the driving direction (X-X);- the piston (7) has a sliding portion (70) slidably mounted within the guide (50a) along the driving direction (X-X);- the guide portion (50a) and the sliding portion (70) have a conformation adapted to prevent the rotation of the piston (7) around the rotation axis (R-R) with respect to the main body (2).

9. Pump (1) according to any one of the preceding claims, wherein:- the main body (2) defines two cavities (20a, 20b) spaced apart and opposite each other along the driving direction (X-X);- the pump (1) comprises two flexible membranes (3a, 3b) mounted on the main body (2) and defining respective variable-volume pumping chambers (4a, 4b) with the cavities (20a, 20b) to which they are functionally associated, said two flexible membranes (3 a, 3b) being spaced apart along the driving direction (X-X);- the piston (7) mainly extends along the driving direction (X-X) between opposite end portions (71, 72) fixed to the respective flexible membranes (3a, 3b); - the transmission elements (8) are interposed between the two flexible membranes(3a, 3b) along the driving direction (X-X).

10. Pump (1) according to any one of the preceding claims, comprising a first and a second group of bearings (9a, 9b) arranged at opposite ends (60b) of the rotor (60) and configured to mount the rotor on the main body (2) so as to prevent the respective motion thereof along the driving direction (X-X), the first group of bearings (9a) comprising a pair of opposite ball bearings or oblique roller bearings (90a, 91a), while the second group of bearings (9b) comprising a radial bearing (90b).

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