WO2009010844A1

WO2009010844A1 - Machine for fluid pumping

Info

Publication number: WO2009010844A1
Application number: PCT/IB2008/001808
Authority: WO
Inventors: Vanna Zaccarelli
Original assignee: Vanna Zaccarelli
Priority date: 2007-07-13
Filing date: 2008-07-11
Publication date: 2009-01-22
Also published as: ITMO20070236A1; EP2171215A1

Abstract

A machine (1) for fluid pumping, comprising at least one substantially hollow pump body (2) provided with a first intake port (3) for a fluid and with a second delivery port (4) for the fluid, at least one bushing element (15) which can be inserted within the pump body (2) and is provided with a cylindrical cavity (18), at least one rotor (19) which can be arranged within the cylindrical cavity (18) and can rotate about an axis of rotation which is substantially parallel to the axis of the cylindrical cavity, and at least one element (22) for pushing the fluid which can be associated with the rotor (19) and is adapted to slide on the surface of the cylindrical cavity (18), the cylindrical cavity being substantially eccentric with respect to the rotation axis. The particularity of the invention is that it comprises at least one kit (25a) of bushing elements (15), the cylindrical cavities (18) of which differ from each other in their different eccentricity with respect to the axis of rotation.

Description

MACHINE FOR FLUID PUMPING Technical field

The present invention relates to a machine for fluid pumping. Background art Various types of pump for aspirating and delivering liquids within hydraulic circuits for industrial, food and/or other uses are known. One particular type of pump is the so-called vane pump. It consists of a hollow pump body, inside which a vaned impeller is accommodated. The impeller is constituted by a rotor, which is actuated rotationally by means of a generic motor, which is usually electric, and on which there is a series of radial recesses.

A corresponding number of vanes can slide within the radial recesses and protrude from the recesses due to centrifugal force or due to thrust on the part of a series of helical springs which are interposed between the vanes and the rotor.

The free end of the vanes is thus pushed into sliding contact against a bushing element, which is inserted in the pump body and is arranged around the impeller. The internal surface of the bushing element is cylindrical, with a circular cross-section and with a central axis which is substantially eccentric with respect to the rotation axis of the impeller.

During rotation, a volume forms between two consecutive vanes and increases at the intake and decreases at the delivery, conveying the fluid from the intake port of the pump to the delivery port.

The extent of the eccentricity determines the volume of fluid processed for each turn of the rotor and consequently affects the flow-rate of the pump.

The more sophisticated vane pumps are provided with systems for adjusting the position of the bushing element inside the pump body. These adjustment systems allow to vary the eccentricity of the bushing with respect to the rotation axis of the impeller, and this allows to vary the flow-rate of the pump.

As an alternative to these adjustment systems, it is also possible to use a variable-speed motor which allows to modify the flow-rate of the pump by reducing or increasing the rotation rate of the impeller.

The pump body, the impeller and the bushing element are usually made of metallic material, which depending on the liquid being processed can be stainless steel or not. The bushing element is particularly subject to wear and is often subject to replacement with other identical elements.

Traditional vane pumps have some drawbacks.

In this regard, the fact is stressed that the simplest pumps not provided with flow-rate adjustment systems are capable of operating only at a specific flow-rate value which is predetermined during manufacturing and which, in view of the many changeable requirements of application, is a severe limitation in use.

Pumps provided with systems for adjusting the eccentricity and/or angular velocity of the impeller, however, have a considerable structural complexity and are affected by particularly high production costs, which negatively affect the final sale price.

Another type of pump is constituted by cycloidal lobe pumps.

These pumps, too, have a hollow pump body inside which an impeller is actuated rotationally which allows to transfer the liquid from the intake to the delivery.

In these pumps, the impeller consists of an outer ring, which rotates snugly within the bushing element, and of an inner rotor, which is actuated rotationally by the motor.

The rotation axis of the rotor is defined by the motor shaft and is eccentric with respect to the rotation axis of the ring, which is instead defined by the bushing element.

The inner surface of the ring and the outer surface of the rotor are contoured so as to form cycloidal lobes, the profiles of which are determined so that during their rotation they remain in sliding contact and isolate a series of volumes of liquid, which are transferred from the intake to the delivery.

The cycloidal lobe pump type, however, also has several drawbacks. These pumps, too, are in fact usually dedicated to the processing of a constant flow-rate, with consequent operating limitations. In a manner similar to vane pumps, moreover, it is possible to adjust their flow-rate by coupling them to variable-speed motors, which inconveniently have rather high manufacturing costs. Disclosure of the Invention

The aim of the present invention is to provide a machine for fluid pumping whose flow-rate can be adjusted in a manner which is practical, easy and functional and which at the same time can be manufactured industrially with considerably low manufacturing costs.

Within this aim, an object of the present invention is to provide a machine for fluid pumping that allows to overcome the mentioned drawbacks of the background art in a solution which is simple, rational, and easy and effective to use.

This aim, this object and others that will become better apparent hereinafter are achieved by the present machine for fluid pumping, which comprises at least one substantially hollow pump body provided with a first intake port for a fluid and with a second delivery port for the fluid, at least one bushing element which can be inserted within said pump body and is provided with a cylindrical cavity, at least one rotor which can be arranged within said cylindrical cavity and can rotate about an axis of rotation which is substantially parallel to the axis of said cylindrical cavity, and at least one element for pushing the fluid which can be associated with said rotor and is adapted to slide on the surface of said cylindrical cavity, said cylindrical cavity being substantially eccentric with respect to said rotation axis, characterized in that it comprises at least one kit of said bushing elements, the cylindrical cavities of which differ from each other in their different eccentricity with respect to said axis of rotation. Brief description of the drawings

Further characteristics and advantages of the invention will become better apparent from the following description of some preferred but not exclusive embodiments of a machine for fluid pumping, illustrated by way of non-limiting example in the accompanying drawings, wherein:

Figure 1 is an exploded view of a particular embodiment of the machine according to the invention;

Figure 2 is a perspective view of the kit of bushing elements provided in the machine of Figure 1; Figure 3 is a sectional view of the machine of Figure 1;

Figure 4 is an exploded view of an alternative embodiment of the machine according to the invention;

Figure 5 is a perspective view of the kits of bushing elements, rotors and rings provided in the machine of Figure 4; Figure 6 is a front view, partially in phantom lines, of the machine of

Figure 4. Ways of carrying out the Invention

With reference to the figures, the reference numeral 1 generally designates a machine for fluid pumping. The machine 1 comprises an internally hollow pump body 2, which has a first port 3, dedicated to aspirating the fluid to be pumped, and a second port 4, which is dedicated to the delivery of the fluid to be pumped.

Within the pump body 2 there is a first region 5, which faces the first port 3, and a second region 6, which faces the second port 4. Safety valve means 7 are interposed between the first region 5 and the second region 6 and are adapted to limit the pressure of the fluid at the output from the pump body and prevent it from exceeding a preset threshold value.

Said safety valve means comprise a bypass duct 8, which is formed in the pump body 2 and connects the first and second regions 5, 6.

A flow control element 9 is accommodated within the bypass duct 8 and can slide along the duct in contrast with the action of a spring 10.

In particular, the ends of the spring 10 are arranged in abutment respectively against the flow control element 9 and against a plug 1 1 , which closes the free end of the bypass duct 8.

In practice, the flow control element 9 keeps closed the passage between the regions 5, 6 through the bypass duct 8 until the pressure of the fluid in output reaches such a value as to allow the compression of the spring 10 and the opening of the bypass duct 8. Conveniently, the pump body 2 and the bypass duct 8 are made of plastics and are formed monolithically, for example by injection molding polymeric material.

The pump body 2 has an open side 12 for inserting therein the components designed to move the fluid. The open side 12 of the pump body 2 can be closed by means of a closure plate 13, which can be screwed onto said body by means of suitable screws 14.

Through the open side 12, it is possible to insert in the pump body 2 a bushing element 15, which is constituted for example by an annular portion 16 and by a bottom wall 17 which is associated with an axial end of the annular portion 16.

The internal surface of the annular portion 16 forms a cylindrical cavity 18, within which it is possible to arrange a rotor 19, which can rotate about a rotation axis A which is parallel and eccentric with respect to the axis of the cylindrical cavity 18. In detail, the rotor 19 is turned by way of motor means 20, such as an electric motor which can be associated with the pump body 2 on the opposite side of the closure plate 13 and is provided with a rotating shaft 21, which can be inserted within the pump body 2 and on which the rotor 19 can be keyed.

At least one fluid pusher 22 can be associated with the rotor 19 and is adapted to slide on the surface of the cylindrical cavity 18.

In the particular embodiment of the invention shown in Figures 1 to 3, for example, the rotor 19 and the pusher 22 are of the vane type. In this particular embodiment, in fact, the pusher 22 consists of a plurality of vanes inserted so that they can slide within corresponding recesses 23 formed within the rotor 19.

Inside each recess 23 there is also a spring 24, which facilitates the exit of the corresponding vane 22. Advantageously, the machine 1 shown in Figures 1 to 3 is provided with a kit 25a of bushing elements 15, the cylindrical cavities 18 of which differ from each other due to their different eccentricity with respect to the rotation axis A, so as to allow to vary the flow-rate of the machine 1 by simple replacement of the bushing elements 15 within the pump body 2. In particular, the outer surfaces of the bushing elements 15 are substantially mutually identical, and this makes them mutually interchangeable.

Said outer surfaces have contoured coupling means 26, 27 for their snug insertion within the pump body 2. The contoured coupling means 26, 27 are of the interlocking type and consists of a pair of slots 26, which are formed on the inner surface of the pump body 2, and respective pairs of protrusions 27, which are formed on the outer surfaces of the bushing elements 15 and can be inserted snugly within the slots 26. The internal surfaces of the bushing elements 15 instead have mutually different diameters and such an arrangement that once they are installed in the pump body 2 their eccentricities with respect to the rotation axis A are different.

Conveniently, a first opening 28 for the passage of the fluid that arrives from the first port 3 and a second opening 29 for the passage of the fluid directed toward the second port 4 are provided in the bushing elements 15.

In the bushing elements 15 of the kit 25a shown in Figure 2, both the first opening 28 and the second opening 29 are provided on diametrically opposite sides of the annular portion 16.

In an alternative embodiment of the invention shown in Figures 4 to 6, the rotor 19 and the pusher 22 are of the type with cycloidal lobes.

In this embodiment, the pusher 22 in fact consists of a ring which is provided with a cylindrical outer surface which is complementary to the cylindrical cavity 18, the inner surface of the ring 22 and the outer surface of the rotor 19 being shaped like cycloidal lobes adapted to mesh together.

Advantageously, the machine 1 shown in Figures 4 to 5 is provided with a kit 25b of bushing elements 15, with a kit 30 of rings 22 which are contoured as a function of the cylindrical cavities 18, and with a kit 31 of rotors 19 which are contoured as a function of the rings 22.

In a manner similar to the bushing elements 15 of the kit 25a, the bushing elements 15 of the kit 25b also are contoured externally with mutually identical shapes, are provided with the coupling means 26, 27, and are mutually interchangeable inside the pump body 2. The cylindrical cavities 18 of the kit 25b, moreover, differ from each other in their different eccentricity with respect to the rotation axis A.

Each bushing element 15 of the kit 25b is in fact matched by a corresponding ring 22 of the kit 30, which is shaped so as to be inserted snugly within the corresponding cylindrical cavity 18, and a corresponding rotor 19 of the kit 31, which is contoured to mesh with the inner surface of the corresponding ring 22.

By alternating the set of bushing elements 15, rotors 19 and rings 22 that correspond to each other within the pump body 2, it is possible to modify the flow-rate of the machine 1. In the embodiment of Figures 4 to 6 also, the bushing elements 15 have a first opening 28 and a second opening 29, which are both provided in the bottom wall 17.

Advantageously, the bushing elements 15, the rotors 19 and the pushers 22 of both embodiments shown in the figures are made of a material such as plastics, stainless steel, ceramics, glass or the like.

In practice it has been found that the described invention achieves the intended aim and object. ^

In this regard, the fact is stressed that the particular solution of providing multiple kits of bushing elements, of rotors and of pushers allows to obtain a multifunction machine, which is capable of varying, in a practical and easy manner, its flow-rate simply by choosing the bushing elements having the desired eccentricity.

Moreover, it is noted that by combining the kits of bushing elements, the kit of rotors and the kit of pushers shown in the present invention it is possible to have a machine for fluid pumping which, according to requirements, can operate both as a vane pump and as a cycloidal lobe pump.

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

All the details may further be replaced with other technically equivalent elements.

In practice, the materials used, as well as the contingent shapes and dimensions, may be any according to requirements without thereby abandoning the scope of the protection of the appended claims. The disclosures in Italian Patent Application No. MO2007A000236, from which this application claims priority, are incorporated herein by reference.

Where technical features 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 do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims

1. A machine for fluid pumping, comprising at least one substantially hollow pump body provided with a first intake port for a fluid and with a second delivery port for the fluid, at least one bushing element which can be inserted within said pump body and is provided with a cylindrical cavity, at least one rotor which can be arranged within said cylindrical cavity and can rotate about an axis of rotation which is substantially parallel to the axis of said cylindrical cavity, and at least one element for pushing the fluid which can be associated with said rotor and is adapted to slide on the surface of said cylindrical cavity, said cylindrical cavity being substantially eccentric with respect to said rotation axis, characterized in that it comprises at least one kit of said bushing elements, the cylindrical cavities of which differ from each other in their different eccentricity with respect to said axis of rotation.

2. The machine according to claim 1, characterized in that it comprises motor means which can be associated with said pump body and are adapted to rotationally actuate said rotor.

3. The machine according to one or more of the preceding claims, characterized in that it comprises safety valve means which are interposed between said first port and said second port and are adapted to limit the pressure of the fluid in output from said pump body.

4. The machine according to one or more of the preceding claims, characterized in that said safety valve means comprise at least one bypass duct, which is formed within said pump body between said first port and said second port, and at least one flow control element, which can slide within said bypass duct in contrast with the action of at least one spring.

5. The machine according to one or more of the preceding claims, characterized in that said bypass duct and said pump body are formed monolithically as a single body.

6. The machine according to one or more of the preceding claims, characterized in that said pump body comprises a substantially open side which is suitable for the insertion of at least one of said bushing elements, said rotor and said pusher, and can be closed by means of at least one closure plate.

7. The machine according to one or more of the preceding claims, characterized in that said pump body is made of plastics.

8. The machine according to one or more of the preceding claims, characterized in that at least one among said bushing elements, said rotor and said pusher is made of a material selected from the list that comprises: plastics, stainless steel, ceramics, glass or the like.

9. The machine according to one or more of the preceding claims, characterized in that it comprises contoured coupling means for the snug insertion of said bushing elements within said pump body.

10. The machine according to one or more of the preceding claims, characterized in that said contoured coupling means are of the interlocking type.

1 1. The machine according to one or more of the preceding claims, characterized in that said contoured coupling means comprise at least one slot, which is formed on the outer surface of said bushing elements and/or on the inner surface of said pump body, and at least one protrusion, which is formed respectively on the outer surface of said bushing elements and on the inner surface of said pump body and can be inserted substantially snugly within said slot.

12. The machine according to one or more of the preceding claims, characterized in that the outer surfaces of said bushing elements are substantially mutually identical.

13. The machine according to one or more of the preceding claims, characterized in that said bushing elements comprise at least one annular portion, the inner surface of which forms said cylindrical cavity.

14. The machine according to one or more of the preceding claims, characterized in that said bushing elements comprise at least one bottom wall, which is associated with an axial end of said annular portion.

15. The machine according to one or more of the preceding claims, characterized in that said bushing elements comprise at least one first opening for the passage of the fluid that arrives from said first port and at least one second opening for the passage of the fluid directed toward said second port.

16. The machine according to one or more of the preceding claims, characterized in that it is of the vane type.

17. The machine according to claim 16, characterized in that said pusher comprises a plurality of vanes which are inserted slidingly within corresponding recesses formed within said rotor.

18. The machine according to one or more of claims 16 and 17, characterized in that at least one among said first and second openings for the passage of the bushing elements is provided on said annular portion.

19. The machine according to one or more of the preceding claims, characterized in that it is of the type with cycloidal lobes.

20. The machine according to claim 19, characterized in that said pusher comprises a substantially annular ring which has an outer surface which is substantially complementary to said cylindrical cavity, the internal surface of said ring and the outer surface of said rotor being shaped like cycloidal lobes which are adapted to mesh together.

21. The machine according to one or more of claims 19 and 20, characterized in that at least one of said first and second openings for the passage of the bushing elements is provided in said bottom wall.

22. The machine according to one or more of claims 19 to 21, characterized in that it comprises a kit of said rings which are contoured according to said cylindrical cavities of the bushing elements.

23. The machine according to one or more of claims 19 to 22, characterized in that it comprises a kit of said rotors which are contoured according to said cylindrical cavities of the bushing elements.