The present invention relates to a vane pump.

The term vane pumps (or rotary vane pumps) refers to a type of positive displacement pump.

As with all positive displacement pumps, the flow rate delivered is always directly proportional to the speed.

Rotary vane pumps are available with different types of vanes: sliding, flexible, oscillating, rotating and external.

Vane pumps are known for their dry priming, ease of maintenance and good suction characteristics over the life of the pump.

Despite the different configurations, most vane pumps operate according to the same general principle hereinafter described.

A grooved rotor is eccentrically supported by an assembly of fixed elements.

The rotor is located close to the wall of the assembly of fixed elements so as to form a crescent-shaped cavity.

The vanes fit into the rotor recesses. As the rotor rotates and the fluid enters the pump, the centrifugal force, hydraulic pressure and/or pushrods push the vanes towards the walls of the containment body.

The containment body defines a suction line, a feed line and a containment volume interposed between them.

The tight fit between the vanes, the rotor and the assembly of fixed elements leads this technology to have good suction characteristics.

The containment body and assembly of fixed elements force fluid into the feed line through holes in the assembly of fixed elements.

The fluid enters the cavities created by the vanes, the rotor and the assembly of fixed elements. As the rotor continues to turn, the vanes sweep the fluid from the mouth of the suction line to the opposite side of the crescent where it is pushed through the discharge holes of the assembly of fixed elements.

The fluid then flows out of the mouth of the feed line.

The general architecture of the vane pumps therefore consists of three main elements: a rotating body, an assembly of fixed elements and a containment body.

As an example of the prior art, US2021/095664 illustrates a vane pump comprising a rotor, a plurality of vanes, a cam ring, a side member brought into contact with a first end surface of the cam ring, a cover member brought into contact with a second end surface of the cam ring and attached to the vane pump body itself, and finally a connecting member configured to connect and extend between the side member and the cover member on an outer circumferential surface of the cam ring.

As a further example of the prior art, US2022/170458 illustrates a vane pump including a side member, a cover member, grooves formed in the outer circumferential surfaces of the side member and the cover member so as to extend in a circumferential direction; and a connecting member configured to connect the side member and the cover member; in this vane pump, the connecting element comprises in turn a first support portion configured to support the side member, a second support portion configured to support the cover member, and an extended portion formed so as to extend between the first support portion and the second support portion, the extended portion extending in an axial direction of the rotor.

The prior art on the architecture described so far encounters various movement-related operation problems and in particular undesired rotations.

One example is the rotation of the assembly of fixed elements, which can occur during the assembly/disassembly steps or during the normal pump operation step. The rotation results in the displacement of the openings of the mouths of the suction line and feed line.

The displacement, relative to the normal positioning conditions of the homologous openings in the containment body, generates the partial or total obstruction and modification of the separation geometries between the feed area (high pressure) and the suction area (low pressure).

The phenomenon described results in bottlenecks and internal leaks, which ultimately produce a reduction in hydraulic performance for the same amount of absorbed mechanical power.

There are many mechanical elements that the literature offers to prevent a mechanical member in a container from rotating, such as keys, tabs, threaded elements and friction elements.

The disadvantage of many of these systems is the high cost and/or size thereof.

The solution typically used for this type of pumps is to assemble an O-ring, with a large cross-sectional dimension, above the assembly of fixed elements. The O-ring is strongly compressed, thus generating considerable friction between the parts.

The friction reaches sufficient values to overcome the forces arising within the pump during operation.

However, the solution proposed in the literature is not entirely conclusive.

The O-ring, in fact, like other mechanical elements mentioned, cannot prevent assembly errors.

Furthermore, the O-ring compression depends on the tolerances of many inner elements, resulting in a variability of friction forces within a large population of pumps.

It is therefore impossible to mathematically exclude that the problem will not take place again.

Another recurring problem is the possibility of one component of the assembly of fixed elements rotating relative to the others. An example is the front disc which might rotate relative to the rear disc, with consequences similar to those described above about the overall performance of the pump.

In order to prevent the rotation of one element relative to the other, a small longitudinal “pin” is normally used which, once inserted, prevents relative movements.

The pin appears to be a solution adapted to solve the problem set forth, but it has critical issues during the assembly step. In fact, due to its small size, it is easily susceptible to being dropped or misplaced, hindering assembly operations.

The technical task of the present invention is to make available a vane pump which is able to overcome the drawbacks resulting from the prior art. The object of the present invention is therefore to make available a vane pump wherein the rotation in one or both directions of the internal components with respect to the external containment body is prevented.

A further object of the present invention is therefore to make available a vane pump that prevents the relative rotation and mutual misalignment of the pump inner components.

Furthermore, it is the object of the present invention to make available a vane pump whose assembly is easy and safe.

Finally, the object of the present invention is therefore to make available a vane pump whose elements, capable of preventing the undesired misalignments discussed above, are cheap and little bulky.

The specified technical task and objects are substantially achieved by a vane pump.

Further characteristics and advantages of the present invention will become clearer from the indicative and therefore non-limiting description of an embodiment of a vane pump.

Such description will be set forth herein below with reference to the accompanying drawings, provided for merely indicative and therefore nonlimiting purposes, wherein: Figure 1 is a schematic representation of an exploded view of an embodiment of the rotary vane pump object of the present invention;

Figures 2 and 3 are perspective schematic representations of a first possible embodiment of the rotary vane pump object of the present invention;

Figures 4 and 5 are perspective schematic representations of a second possible embodiment of the rotary vane pump object of the present invention;

Figures 6 and 7 are perspective schematic representations of a third possible embodiment of the rotary vane pump object of the present invention.

With reference to the attached figures, the rotary vane pump has been overall referred to as vane pump 1 .

The vane pump 1 for handling fluids comprises a containment body 2 which defines a suction line 3, a feed line 4 and a containment volume 5 interposed between the last two mentioned elements, i.e. placed in communication with the suction line 3 and the feed line 4.

The vane pump 1 is also provided with a rotor 6 arranged within a stator 23 which is in turn placed within the containment volume 5 and comprising at least two vanes 7.

The volumes of fluid are defined between two consecutive vanes 7.

Vane 7 can refer to an elongated body whose ends define the elements that, together with the ends of other vanes 7, in contact with the other fixed components, define the aforementioned volumes of fluid.

Alternatively, vane 7 can refer to the single end of the elongated body.

In other words, vane 7 can refer to any element placed in rotation with the rotor 6 that defines a volume of fluid adapted to handle the fluid.

The rotor 6 is preferably provided with a plurality of vanes 7 so as to define at least two volumes of fluid. The rotor 6, generally consisting of a shaft, then moves an impeller provided with vanes 7 to handle the fluid from the suction line 3 to the feed line 4.

Between the containment volume 5 and the rotor 6, an assembly of fixed elements 8 is interposed, of which the stator 23 is a part, so as to define a cavity in which the rotor 6 can rotate. In particular, the assembly of fixed elements 8 defines a cavity in which the vanes 7 can rotate.

Preferably, the assembly of fixed elements 8 comprises three fixed elements as depicted in the attached figures. Alternatively, the assembly of fixed elements 8 may comprise two fixed elements or more than three fixed elements.

The vane pump 1 may also have mechanical closing elements 22 such as keys, tabs and fixed elements adapted to maintain a stable hydraulic sealing.

Preferably an O-ring is used as a mechanical closing element for the static hydraulic sealing function. Whereas a mechanical sealing 22 is usually used to prevent the hydraulic leakage in the dynamic coupling between the containment body 2 and the shank of the rotor 6

The vane pump 1 has at least one interference element 9 located between the containment body 2 and the assembly of fixed elements 8 and housed at least partially in one of the last two elements mentioned above.

The interference element 9, which is the subject of the present invention, consists of one or more elements made of any material.

Preferably the interference element 9 is made of stainless steel.

The interference element 9 is designed to be installed within the containment volume 5 so as to be housed within the containment body 2 and/or the assembly of fixed elements.

Preferably, if the interference element 9 is at least partially housed in the containment body 2, it is housed within a compartment of the suction line 3 and/or the feed line 4 of the vane pump 1 .

Preferably, the interference element 9 is housed at least partially inside the suction line 3 and/or inside the feed line 4.

Even more preferably, the containment volume 5 defines at least a first housing seat 10 wherein the interference element 9 is at least partially housed.

According to another possible embodiment of the present invention, the interference element 9 is housed in the assembly of fixed elements 8 and interfaced with the suction line 3 and/or feed line 4 compartment.

Preferably, the assembly of fixed elements 8 defines at least a second housing 11 wherein the interference element 9 is at least partially housed.

An interference element 9, coupled with appropriate housing geometries in the assembly of fixed elements 8, once mounted and assembled, plays a dual function on the vane pump 1 .

The interference elements 9, in fact, simultaneously manage both to align the fixed elements of the assembly of fixed elements 8 and to keep the assembly of fixed elements 8 in position within the containment volume 5. Advantageously, these two functions can be performed with no need for high friction forces generated by the O-ring or other mechanical closing elements 22, which only have a hydraulic sealing function.

Preferably, the interference element 9 is installed both within the suction line 3 and/or feed line 4 compartment and within the assembly of fixed elements 8.

The interference element 9 can be sized in such a way that it remains permanently coupled, due to its elasticity, with the suction line 3 and/or feed line 4 compartment.

Alternatively, the interference element 9 can be further sized so that it remains in a fixed coupling, due to its own elasticity, with appropriate geometries obtained in the fixed elements of the assembly of fixed elements 8.

These two disclosed configurations do not add complexity to the assembly/disassembly operations of the vane pumps 1 as the locations defined by the fixed elements and/or the suction line 3 and feed line 4 allow to easily insert the interference elements 9. In other words, the assembly of the vane pumps 1 has no added complexity compared to the assembly of the vane pumps 1 present in the prior art.

It follows that the addition of the interference element 9 provides additional technical operating and safety features to the vane pump 1 , without affecting the aspects of the essential elements found in the literature.

According to one possible embodiment, the interference element 9 is made in the form of a shaped spring 12 comprising two ends 13 and a central portion 14 defined between the two ends 13.

The interference element 9 in the form of a moulded spring 12 is shaped in such a way that it engages with the suction line 3 or the feed line 4 and abuts with the assembly of fixed elements 8.

The shaped spring 12, when the vane pump 1 is assembled, undergoes a slight deformation and fits in the position described above, preventing the misalignment of the parts and the rotation within the vane pump 1 .

Preferably, the two ends 13 of the interference element 9 in the form of a shaped spring 12 are shaped so as to engage in the first housing seat 10 and, at the same time, the central portion 14 assumes a positioning and shape such as to abut with the second housing seat 11 .

Advantageously, the shaped spring 12 interference element 9 in no way hinders the disassembly operations, which can be carried out by performing the assembly operations backwards.

According to another possible embodiment of such an interference element 9, the shaped spring 12 is a flat spring 15.

Preferably, the interference elements 9 in the form of a flat spring 15 are generally used in pairs as shown, for example, in Figure 4, which shows two flat springs 15 mounted so as to abut against different portions of the compartment defined by the feed line 4.

Advantageously, the assembly of the flat spring 15 is further simplified as it is not pre-loaded or deformed in any way when it is assembled.

Once in place, the flat springs 15 create protrusions that allow to prevent undesired or excessive rotations of the assembly of fixed elements 8 within the containment volume 5 of the vane pump 1 .

The alignment of the fixed elements 8 is ensured by the geometric couplings with the pair of flat springs 15, both in the deformed and relaxed state.

In fact, the flat springs 15 deform during insertion, only to resume to their original size once they are inside the recess of the suction line 3 or feed line 4.

According to a third possible embodiment, the interference element 9 has a first portion 16 that is counter-shaped relative to the second housing seat 11 .

This interference element 9 is inserted within the second housing seat 11 , and has a second portion 17 opposite the first portion 16 that is adapted to abut against the first housing seat 10.

This last embodiment of the proposed interference element 9 has at least two bodies 18 extending parallel to an axis of rotation 19 of the rotor 6 (hereinafter parallel bodies 18) and two arcs 20 for connecting the parallel bodies 18 by means of the ends thereof. In other words, the arcs 20 extend along the outer surface of the assembly of fixed bodies 8 (i.e. along the surface on which they rest within the second housing seat 11 ) so as to connect the two parallel bodies 18. Thereby, in the event of possible misalignments, one parallel body 18 transmits the movement to the other parallel body 18 by means of the arcs 20, which will abut against one end of the housing seat 11 so as to prevent misalignment of the various components of the vane pump 1 .

Furthermore, the interference element 9 comprises, as shown in Figure 6, at least two bodies 21 radial to the axis of rotation 19 extending from the two connecting arcs 20 i.e. from the parallel bodies 18.

In other words, the proposed interference element 9 has a design with two “skids” connected by other rods, whose task is to give the interference element 9 solidity, thus constituting a single piece. In this last described configuration, the inside of the containment body 2 of the vane pump 1 and the outside of the assembly of fixed elements 8 are provided with special grooves wherein the “skids” of the interference element 9 are inserted.

Once the interference element 9 is assembled in the assembly, all the relative rotational movements between the containment body 2 of the vane pump 1 and the assembly of fixed elements 8 are completely prevented.

The fixed elements thus remain perfectly aligned with each other and correctly positioned in relation to the containment body 2 of the vane pump 1.

The interference element 9 is highly visible after being assembled, making it possible to carefully check the correct assembly.

Preferably, the interference elements 9 can be made in shapes differing from those described above, but with similar elements to prevent undesired misalignment of the vane pump 1 components.

Advantageously, the operations required to assemble the interference element 9, which is the subject of the present invention, are facilitated and simplified.

Advantageously, the interference element 9 has simple geometries that are easy to manufacture and thus cost-effective.

Advantageously, the other mechanical closing elements of the vane pump 1 , in the present invention, are now only intended for the hydraulic closing function and can therefore be modified and simplified with considerable ease.