ES2374715T3 - MULTIPLE MEMBRANE PUMP FOR FOOD AND SIMILAR LIQUIDS. - Google Patents

Abstract

A multi-membrane pump for food liquids and the like comprising: at least one inlet duct (6) for the compensated inlet of the liquid, which is itself closed in a loop and is provided with at least one inlet port (7 ); at least one delivery conduit (8) for the compensated delivery of the liquid, which is itself closed in a loop and is provided with at least one delivery port (9); at least four branches (10, 11, 12, 13), in which each of the branches provides a fluid connection between said inlet duct (6) and said delivery duct (8) and is associated with a pumping membrane of liquid (14, 15, 16, 17); and a gearmotor group (18), the pump being characterized by the fact that each of the branches comprises at least one inlet valve (29) located in the connection to said inlet duct (6) and at least one inlet valve delivery (30) located in the connection to said delivery conduit (8), thus providing a unidirectional fluid connection between said inlet conduit (6) and said delivery conduit (8), and by the fact that said geared motor group ( 18) is associated with a crank system (19) for activating said membranes (14, 15, 16, 17) which is adapted to convert the rotational movement of an output shaft (20) of said geared motor group (18) into a reciprocating movement, adjusted with appropriate coordination between two mutually opposite travel limiting positions of entry and delivery of each of the activation axes (21, 22, 23, 24) of said membranes (14, 15, 16, 17).

Description

Multiple membrane pump for food liquids and the like.

The present invention refers to a multi-membrane pump for food liquids and the like.

The food industry (particularly but not exclusively with reference to the production of wines and the like) traditionally uses, for the transfer of liquids, piston pumps, helical screw pumps, centrifugal pumps, peristaltic pumps or, alternatively, membrane pumps that They are activated pneumatically or electromechanically.

Membrane pumps are often preferred to piston, helical screw, centrifugal and peristaltic pumps due to their smaller size and lower noise, their gentle pumping, the absence of mechanical seals, the possibility of operating when they are empty or with delicate, viscous and abrasive fluids, even containing suspended solids; such membrane pumps currently comprise, in the most advanced version, two mutually opposite pumping elements, each provided with a respective membrane, both connected to an inlet conduit and a delivery conduit; such pumping elements are normally activated in phase opposition to one another, that is, when one is at the end of the inlet passage the other is at the end of the delivery step and vice versa.

DE 2059903A1, showing a peristaltic pump according to the preamble of claim 1, has a pump housing with a cylindrical internal cavity. The housing is closed with a cover at the front and at the back. One of the covers is connected to a motor that moves a rotor. The rotor has at its ends rollers that are associated with a pumping space that includes a dome-shaped membrane.

Membrane pumps of the type described here are not free from inconveniences. First, they generate a fairly uneven flow of liquid, that is, with a very striking pulsed flow rate: this fact, for particularly delicate food processes, such as wine packaging and the like, is of course very disadvantageous, because it subjects to the liquid at mechanical stresses that could alter and compromise its organoleptic properties and therefore its quality. Second, they can deliver a flow rate that in many applications is not enough even using large diameter membranes.

Thirdly, they do not provide flow inversion systems, which allow selectively connecting the ports for coupling to external sources or tanks to the delivery conduit or the inlet conduit.

Fourth, the pumps generally used today in the food industry are expensive, demanding in terms of maintenance, noisy, inefficient in terms of energy due to high internal friction and inefficient types of lubrication, despite the use of large amounts of lubricating oils and greases.

The objective of the present invention is to avoid the aforementioned drawbacks by providing a multi-membrane pump for food liquids and the like that allows to deliver a liquid flow rate that is as uniform as possible, that is, substantially without striking pulsation phenomena that could alternate the quality of said liquid.

Within this objective, an object of the present invention is to provide a multi-diaphragm pump for food liquids and the like that is capable of delivering flow rates significantly greater than those provided by the currently commercially available membrane pumps.

 Another object of the present invention is to provide a multi-diaphragm pump for food liquids and the like having a flow reversal system that allows the direction of liquid transfer between the external tanks or sources to be reversed.

 Another object of the present invention is to provide a multi-diaphragm pump for food liquids and the like that is easy to maintain, silent, having high energy efficiency and low use of lubricating oil due to low internal friction.

 Another object of the present invention is to provide a multi-membrane pump for food liquids and the like that has a simple structure, that is relatively easy to provide in practice, safe in use, effective in operation and that has a relatively low cost. .

This object and these and other objects that will be apparent better in the following are achieved by the present multi-membrane pump for food liquids and the like as claimed in claim 1.

Other features and advantages of the invention will be better apparent from the following detailed description of a preferred but not exclusive embodiment of a multi-membrane pump for food liquids and the like according to the invention, illustrated by non-limiting example in the accompanying drawings, in which:

Figure 1 is a perspective view of the pump according to the invention;

Figure 2 is a detailed perspective view of the pump base;

Figure 3 is a partially exploded perspective view of section of one of the branches for connecting the inlet conduit to the delivery conduit;

Figure 4 is a detailed plan view of the inlet valve and delivery valve;

Figure 5 is a cross-sectional view taken along the line V-V of Figure 4;

Figure 6 is a side elevation view in detail of the crank system for activating the pump according to the invention;

Figure 7 is a detailed plan view of said crank system.

In the exemplary embodiment that follows, the individual characteristics, given in relation to this specific example, can in fact be exchanged with other different characteristics that exist in other exemplary embodiments.

In addition, it is noted that anything that is discovered as already known during the patenting process is understood to be unclaimed and subject to a waiver.

With particular reference to Figure 1, reference number 1 generally designates a multi-membrane pump for food liquids and the like according to the invention, particularly but not exclusively for liquids such as wine.

The pump comprises a support base, generally designated by the reference number 2, which is constituted by a substantially square frame 3 provided with cross members 4 that intersect in the center; optionally, the square frame 3 may be provided with substantially traditional wheels 5 that are adapted to facilitate the movement of the pump. Four vibration damping elements 5a of a substantially traditional type are interposed between the transverse members 4 and the square frame 3 and dampen and limit the transmission of vibrations to the ground (Figure 2).

 The base 2 advantageously supports, according to the invention, a conduit for the compensated entry of the liquid, generally designated by the reference number 6, which is itself closed in a loop and is provided with at least one input port 7, a conduit for the compensated delivery of the liquid, generally designated by the reference number 8, which is closed in itself in a loop and is provided with at least one delivery port 9; There are also four branches, 10, 11, 12, 13 that provide a unidirectional connection between the inlet conduit 6 and the delivery conduit 8 and are associated respectively with four membranes 14, 15, 16, 17 for pumping the liquid.

The pump also conveniently comprises a geared motor group, generally designated by reference number 18, which is associated with a crank system, generally designated by reference number 19 (Figures 5, 6) for the activation of the four membranes 14, 15, 16, 17, which are adapted to convert the rotary movement of an output shaft 20 of the geared motor group 18 into a reciprocating movement, which is adjusted with proper coordination between two opposite travel limit positions of input and delivery, such as will best be apparent below, of each of the activation axes 21, 22, 23, 24 of the membranes 14, 15, 16, 17. The activation axes 21, 22, 23, 24 of the membranes 14 , 15, 16, 17, respectively connected to said membranes by means of screws V, are preferably arranged at right angles to each other, but in any case they can be arranged, alternatively, in different angles in relation to different requirements.

Each of the membranes 14, 15, 16, 17, as can be seen in Figure 3, is fixed between pairs of plates P1, P2 that facilitate rolling during the movement of the activation axes 21, 22, 23, 24.

The use of four membranes 14, 15, 16, 17 activated in a continuous cycle and in succession with respect to each other allows the delivery of a very regular flow rate that is free of striking pulsations, even at a rotation speed lowering of the gearmotor group 18; This considerable advantage is also achieved by the closed-loop configuration of the inlet duct 6 and the delivery duct 8, which dampens and protects any oscillation phenomenon within the liquid.

In greater detail, the delivery conduit 8 is concentrically arranged above the inlet conduit 6 and is supported by the four branches 10, 11, 12, 13, which accordingly are also mutually angularly equidistant at right angles to each other.

The geared motor group 18 is preferably mounted so that the output shaft 20 is vertical, along a direction that is substantially concentric with respect to the inlet conduit 6 and the delivery conduit 8. The geared motor group 18 is of the type activated by an electric motor 25, which is controlled with an electronic frequency inverter. Alternatively, a hydraulic, pneumatic, or internal combustion engine or a power take-off or cardan shaft or an engine of any other type could also be used.

Each of the branches 10, 11, 12, 13 (Figure 3) is substantially formed as a laterally inclined letter T and forms a first end for connection to the inlet conduit 6, a second end for connection to the delivery conduit 8 , and a third end for connection to the respective membrane 14, 15, 16, 17; each of the branches 10, 11, 12, 13 comprises an inlet valve 29 and a delivery valve 30, which are arranged respectively at the first end 26 and the second end 27.

Inlet valves 29 and delivery valves 30 are conveniently of the type with a ball-shaped flow control element 31 (also known as ball check valves), but alternatively it is also possible to use flap check valves or duckbill check valves or cone check valves. More precisely, in the exemplary embodiment with a ball-shaped flow control element, each inlet valve 29 and delivery valve 30 comprises a tubular segment that is affected by a fluid passage channel 33 which is hermetically disposed thereon. of an interchangeable and reversible seat 34 against which the ball-shaped flow control element 31 abuts by gravity. The seat 34 in turn rests on a kind of cup T, which is adapted to provide a connection to the ducts.

The channel 33 is provided with linear guides provided with a stop element 34a and simple linear guides 34b, which are alternately arranged at right angles to each other and allow the flow control element 31 to be guided in a straight way from its inactive position in the seat 34 to the fully raised position, established by a retaining tooth 34c of each of the guides 34a: this allows a faster gravity closure of the ball-shaped flow control element 31 in the seat 34, for effectively use delivery valve 30 and inlet valve 29 even at high pumping speeds. The channel 33 has a transverse cross-section that accordingly forms four peripheral sectors 35, which are angularly equidistant and are adapted to give the valves 29, 30 a minimum resistance to the passage of the fluid and through which any suspended solid, even of substantial dimensions, transported by said fluid, it can flow freely without being crushed by the ball-shaped flow control element 31 against the inner wall of the channel 33; said fluid can thus provide a self-cleaning effect in said channel (for example, it is possible to pump fruit salad

or similar without breaking the pieces of fruit, which must remain intact)

The first ends 26 and the second ends 27 of each of the branches 10, 11, 12, 13 are connected to substantially T-shaped R couplings, are provided with respective G rings (or for example clamps of the tri-clamp type or similar) to fix the branches 10, 11, 12, 13, and are connected respectively to the inlet duct 6 and the delivery duct 8 (each consisting of five pieces of rubber, plastics or metal pipes), by hermetic clamps F or also through projections.

The crank system 19 for activating the membranes 14, 15, 16, 17 (see figures 6, 7) comprises a box 36, which has a cover 36a which is hermetically fixed by means of screws 36b and on which a frame 36c to support the gearmotor group 18 is mounted. The box 36 internally accommodates a first rectangular body 37 and a second rectangular body 38 that are arranged to cross each other at right angles and one above the other, both being arranged above the level of the oil that is present at the bottom of the box 36 and being centrally affected respectively by a first rectangular opening 37a and a second rectangular opening 38a. Each of said bodies is rigidly coupled, on the respective short sides, to two of the activation axes of two of the mutually opposite membranes 14, 15, 16, 17: more precisely, the short sides of the first rectangular body 37 are coupled respectively rigidly to the axes 21, 23, while the short sides of the second rectangular body 38 are rigidly coupled to the axes 22, 24.

The crank activation system 19 further comprises an eccentric pivot 39 that is rigidly coupled to the output shaft 20 of the geared motor group 18 which is arranged so that its axis of symmetry is within the first opening 37a of the first rectangular body 37 and of the second opening 38a of the second rectangular body 38: advantageously, the rotation of the eccentric pivot 39 around the output shaft 20 of the geared motor group 18 allows providing the alternating translational movement of the axes 21, 22, 23, 24 of the membranes 14, 15, 16, 17 one after the other sequentially and in continuous cycle.

The eccentric pivot 39 is provided, at its free end, with two bearings with raceways 40, 41, which are adapted to engage, with an appropriate tolerance and without play, respectively within the first opening 37a of the first rectangular body 37 and inside the second opening 38a of the second rectangular body 38.

The box 36 is associated with four pumping chambers 42, 43, 44, 45, which are angularly equidistant at right angles to each other and within which the four membranes 14, 15, 16, 17 are fixed that are closed by four respective heads 46, 47, 48, 49 that are connected to the four branches 10, 11, 12, 13. The four activation axes 21, 22, 23, 24 of the membranes 14, 15, 16, 17 partially protrude from the box 36 through four respective through holes 50, 51, 52, 53, in which four respective sliding bushes 54, 55, 56, 57 are fixed; advantageously, there are no mechanical seals, since the level of oil contained in the bottom of the case 36 is lower than the level of the pair of the lower sliding bushes 55, 57.

The pump 1 comprises a forced lubrication system, generally designated by the reference number 58, for the crank activation system 19. The lubrication system 58 comprises a gear or vane pump 59, which is connected to the output shaft 20 of the geared motor group 18 at its top, that is, at the opposite end with respect to the eccentric pivot 39. The gear or vane pump 59 is associated with an inlet tube 60, which is connected to a first coupling 61, which it is arranged substantially at the base of the box 36, and to a delivery tube 62, which is connected to a second coupling 63, which is connected to the eccentric pivot 39 by a channel properly provided 64. The lubrication system 58 is conveniently suited for transporting a preset oil flow rate along the channel 64, said oil being extracted from the bottom of the box 36, on the eccentric pivot 39 and of mod or accordingly, substantially by dripping, on the first rectangular body 37 and the second rectangular body 38 to keep them constantly lubricated and cooled.

The pump advantageously comprises a flow reversal element 65 which is associated with a first tubular portion 66 forming a first port 67 for connection to tanks or external sources, and with a second tubular portion 68 forming a second port 69 also for connection to tanks or external sources, and is provided with a manual selection lever 70; the first port 67 and the second port 69 are mutually opposite. The flow reversal element 65 allows selectively connecting the inlet conduit 6 and the delivery conduit 8 to the first port 67 or the second port 69.

Advantageously, there are two expansion vessels 71 and 72 that are adapted to compensate and dampen any oscillation within the liquid in the tubes for the connection between the external tanks or sources and the pump, which are respectively connected to the first tubular portion 66 and the second tubular portion 68 by couplings 73 for example of the ring, tri-clamp, clamp or the like type.

The operation of the pump according to the invention is as follows. The source of liquid to be extracted is connected to the first port 67 or the second port 69, depending on the position of the inversion element 65; An external conduit is connected to the other port and transports the fluid to the destination tank, whatever it is.

Starting the gearmotor group 18, at the rotation speed established according to the chosen flow rate, the output shaft 20 moves the eccentric pivot 39, which in turn imparts an alternating translational movement to the first rectangular body 37 and the second rectangular body 38 and consequently to the pairs of activation axes 21, 22 and 23, 24. Said axes activate in succession, one after the other, the membranes 14, 15, 16, 17, which in a continuous cycle aspirate the liquid flowing to along the inlet duct 6 and along the branches 10, 11, 12, 13 through the inlet valve 29 and the delivery valve 30. The liquid aspirated by the membranes 14, 15, 16, 17 is joined in delivery duct 8 and from there it is transported to the destination tank. Any oscillation within the liquid in the tubes for the connection between the external tanks or sources and the pump is damped and protected in the expansion vessels 71 and 72. In greater detail, the coordination of the rectangular bodies 37, 38 is adjusted so that when a membrane is at the end of the entry passage, the diametrically opposite membrane is at the end of the delivery step, while the other two are respectively halfway to the entrance passage and halfway to the delivery step.

In this way it has been shown that the invention achieves the objective and the intended objects.

The invention conceived in this way is susceptible to numerous modifications and variations, all of which are within the scope of the appended claims.

The pump according to the invention can also have more than four membranes; for example, there may be six membranes associated with three rectangular bodies whose respective activation axes are mutually and angularly equidistant at 60 ° from each other, or eight membranes associated with four rectangular bodies, with respective activation axes arranged to be angularly equidistant at 45 ° from each other. ; In these two cases, the activation crank case has a hexagonal and octagonal plane shape respectively. At the expense of greater constructive complexity, which may also include the need to provide a support with a bearing for the crank system 19 at the bottom of the box 36, even more obvious advantages are achieved in terms of pumping uniformity.

The pump according to the invention can also be used in a useful manner for other fields of use, such as for example purification (sediments), the supply of filter presses, the pumping of powders that can be fluidized and other applications in chemical, ceramic industries and paper

All details can be replaced by technically equivalent ones.

In practice, the materials used, as well as the shapes and dimensions, can be any according to the requirements without leaving the scope of protection of the appended claims.

Where the technical elements mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference signs have no limiting effect on the interpretation. of each element identified by example by such reference signs.

Claims (27)

1. A multi-diaphragm pump for food liquids and the like comprising: at least one inlet conduit (6) for the compensated inlet of the liquid, which is itself closed in a loop and is provided with at least one inlet port (7); at least one delivery conduit (8) for the compensated delivery of the liquid, which is itself closed in a loop and is provided with at least one delivery port (9); at least four branches (10, 11, 12, 13), in which each of the branches provides a fluid connection between said inlet duct (6) and said delivery conduit (8) and is associated with a liquid pumping membrane (14, 15, 16, 17); and a gearmotor group (18), the pump being characterized by the fact that each of the branches comprises at least one inlet valve (29) located in the connection to said inlet duct (6) and at least one inlet valve delivery (30) located in the connection to said delivery conduit (8), thus providing a unidirectional fluid connection between said inlet conduit (6) and said delivery conduit (8), and by the fact that said geared motor group ( 18) is associated with a crank system (19) for activating said membranes (14, 15, 16, 17) which is adapted to convert the rotational movement of an output shaft (20) of said geared motor group (18) into a reciprocating movement, adjusted with appropriate coordination between two mutually opposite travel limiting positions of entry and delivery of each of the activation axes (21, 22, 23, 24) of said membranes (14, 15, 16, 17).

2.

 The pump according to claim 1, characterized in that said activation axes (21, 22, 23, 24) of said membranes (14, 15, 16, 17) are arranged at right angles to each other.

3.

 The pump according to one or more of the preceding claims, characterized in that said delivery duct (8) is concentrically arranged above said inlet duct (6) and is supported by said four branches (10, 11, 12, 13).

Four.

 The pump according to one or more of the preceding claims, characterized in that said geared motor group (18) is mounted such that said output shaft (20) is vertical, along a direction that is substantially concentric with respect to said inlet duct (6) and said delivery duct (8).

5.

 The pump according to one or more of the preceding claims, characterized in that said geared motor group (18) is of the type activated by an electric motor (25) which is controlled by an electronic frequency inverter.

6.

 The pump according to one or more of claims 1 to 4, characterized in that said geared motor group (18) is of the type activated by a hydraulic motor.

7.

 The pump according to one or more of claims 1 to 4, characterized in that said geared motor group (18) is of the type activated by a pneumatic motor.

8.

 The pump according to one or more of claims 1 to 4, characterized in that said geared motor group (18) is of the type activated by an internal combustion engine.

9.

 The pump according to one or more of claims 1 to 4, characterized in that said geared motor group (18) is of the type activated by a power take-off or a cardan shaft.

10.

 The pump according to one or more of the preceding claims, characterized in that each of said branches (10, 11, 12, 13) is substantially formed as a letter T inclined on its side and forms at least one first end for the connection to said inlet conduit (6), at least a second end for connection to said delivery conduit (8) and at least a third end for connection to the membrane (14, 15, 16, 17).

eleven.

 The pump according to one or more of the preceding claims, characterized in that said inlet valve (29) and said delivery valve (30) are of the type with a ball-shaped flow control element (31), also known as ball check valve.

12.

 The pump according to claim 11, characterized in that each of said inlet and delivery valves (29, 30) comprises a tubular segment that is affected by a channel (33) for the passage of the fluid that is hermetically arranged above of an interchangeable and reversible seat (34) against which said ball-shaped flow control element (31) stops by gravity, said channel (33) forming linear guides provided with a stop element (34a) and linear guides simple (34b), which are arranged alternately at right angles to each other to force said ball-shaped flow control element (31) to perform a rectilinear movement from an inactive position in said seat (34) to a completely elevated position , established by the stop tooth (34c) of each of said guides (34a), to achieve rapid gravity closure of said ball-shaped flow control element (31) in said seat to (34) and to use said inlet and delivery valves (29, 30) also at high pumping speeds.

13.

 The pump according to claim 12, characterized in that said channel (33) has a transverse cross-section that forms four peripheral sectors (35) that are adapted to give said inlet and delivery valves (29, 30) a resistor minimum to the flow of liquid and the free flow of any solid body in suspend

sion in the pumped liquid without said bodies being crushed by said ball-shaped flow control element (31) against the inner wall of said channel (33), with a self-cleaning effect of said channel.

14.

 The pump according to one or more of claims 1 to 10, characterized in that said inlet and delivery valves (29, 30) are of the flap check valve type.

fifteen.

 The pump according to one or more of claims 1 to 10, characterized in that said inlet and delivery valves (29, 30) are of the duckbill check valve type.

16.

 The pump according to one or more of claims 1 to 10, characterized in that said inlet and delivery valves (29, 30) are of the cone check valve type.

17.

 The pump according to one or more of the preceding claims, characterized in that said crank system (19) for activating said membranes (14, 15, 16, 17) comprises at least one box (36) within the which a first rectangular body (37) and a second rectangular body (38) are accommodated, said first rectangular body (37) being affected by a first rectangular opening (37a), said second rectangular body

(38) being affected by a second rectangular opening (38a), said bodies (37, 38) crossing at right angles to each other, one above the other, each being rigidly coupled, in pairs, on the respective short sides, to said activation axes (21, 22, 23, 24) of said mutually opposite membranes (14, 15, 16, 17), said crank activation system (19) further comprising at least one eccentric pivot (39), which is coupled rigidly to said output shaft (20) of said geared motor group (18), inserted into said first opening (37a) and said second opening (38a), the rotation of said eccentric pivot (39) about the axis of said axis of said output (20) being adapted to produce the alternating translational movement of said activation axes (21, 22, 23, 24) of said membranes (14, 15, 16, 17) one after the other in succession and in a cycle continuous.

18.

 The pump according to claim 17, characterized in that said eccentric pivot (39) is provided, at its free end, with rolling ring bearings (40, 41) that are adapted to engage within said first opening (37a ) and said second opening (38a).

19.

 The pump according to one or more of the preceding claims 17 and 18, characterized in that said housing (36) is associated with four pumping chambers (42, 43, 44, 45), which are mutually and angularly equidistant at angles. straight and within which said four membranes (14, 15, 16, 17) are accommodated, said membranes being closed by four respective heads (46, 47, 48, 49) that are connected to said four branches (10, 11, 12, 13).

twenty.

 The pump according to one or more of the preceding claims 17 to 19, characterized in that said four activation axes (21, 22, 23, 24) of said membranes (14, 15, 16, 17) protrude from said housing (36) through four respective through holes (50, 51, 52, 53) in which four respective sliding bushes (54, 55, 56, 57) are fixed that are arranged above the level of the oil contained in the bottom of said box (36).

twenty-one.

 The pump according to one or more of the preceding claims, characterized in that each of said membranes (14, 15, 16, 17) is fixed between pairs of plates (P1, P2), which facilitate its rolling during movement of said activation axes (21, 22, 23, 24).

22

 The pump according to one or more of the preceding claims 1 to 16, characterized in that said pump comprises two additional membranes (14, 15, 16, 17) that are associated with three rectangular bodies (37, 38), their respective activation axes being mutually and angularly equidistant at 60 degrees from each other.

2. 3.

 The pump according to one or more of the preceding claims 1 to 16, characterized in that said pump comprises four additional membranes (14, 15, 16, 17) that are associated with four rectangular bodies (37, 38), their respective activation axes being mutually and angularly equidistant at 45 degrees from each other.

24.

 The pump according to one or more of the preceding claims 17 to 21, characterized in that it comprises at least one system (58) for the forced lubrication of said crank activation system (19), said lubrication system (58) comprising at least one gear pump or vane pump (59), which is activated by said output shaft (20) of said geared motor group (18), which is associated with at least one inlet tube

(60) which is connected to said box (36) and at least one delivery tube (62) that is connected to said eccentric pivot (39), said delivery tube (62) being adapted to carry a preset flow rate of oil along said eccentric pivot (39) and, substantially drip, on said first rectangular body (37) and on said second rectangular body (38). 25. The pump according to one or more of the preceding claims, characterized in that it comprises at least one flow reversal element (65) that is connected to at least a first port (67) and at least a second port ( 69) for connection to tanks or external sources, said inversion system (65) being adapted to selectively connect said inlet conduit (6) and said delivery conduit (8) to said first port (67) or said second port (69). 26. The pump according to claim 25, characterized in that it comprises at least one pair of expansion vessels (71, 72), which are adapted to compensate and dampen any oscillation within the liquid in the tubes for the connection between the external tanks or sources and the pump, which are respectively connected to a first tubular portion (66) leading to said first port (67) and to a second tubular portion (68) carrying 5 to said second port (69). 27. The pump according to one or more of the preceding claims, characterized in that it comprises a support base (2) that is constituted by a substantially square frame (3) provided with cross members (4) that cross in the center and to which the lower face of said housing (36) is fixed, said frame (3) being provided with wheels (5) that allow the movement of the pump (4), four vibration damping elements 10 (5a) being interposed between said transverse members (4) and said square frame (3) and damping and limiting the transmission of vibrations to the ground.