WO2017179079A1

WO2017179079A1 - A hollow disk pump of the portable type with variable eccentricity

Info

Publication number: WO2017179079A1
Application number: PCT/IT2016/000095
Authority: WO
Inventors: Silvia MARIANETTI; Michele Costa
Original assignee: 3P Prinz S.R.L.
Priority date: 2016-04-14
Filing date: 2016-04-14
Publication date: 2017-10-19
Also published as: EP3443225B1; EP3443225A1

Abstract

The present invention concerns a hollow disc pump that foresees: An impeller (9); A rotating shaft (3); Means (4, 5, 30, 36) to connect eccentrically the impeller (9) to the rotating shaft (3) in such a way that the impeller (9) can be conducted in rotation by said rotating shaft and contextually can translate, moving near and/or moving apart transversally with respect to the longitudinal axis of said rotating shaft (3); Characterized in that said means comprise a guiding hole obtained transversally in the rotating shaft and a ring (30) suitable for connecting with the impeller (9) and of such internal diameter that the rotating shaft is inserted in such ring with a predetermined radial play, and wherein said ring is provided with a radial pivot (5) that is inserted slidingly in said guiding hole of the shaft in such a way that the ring can move transversally with respect to the rotating shaft (9) through said pivot (5) that can slide in the guiding hole, and wherein elastic means (4) are further foreseen, arranged in such a way that said ring (30) is kept eccentric with respect to the longitudinal shaft with a pre-determined transversal play (d).

Description

TITLE

A HOLLOW DISK PUMP OF THE PORTABLE TYPE Technical field

The present invention concerns the technical field relative to pumps for sending/aspiring a fluid.

' In particular, the invention refers to a hollow disc pump, which is provided with a particular kinematism of transmission of the motion to the impeller that allows to realize such pump of different sizes, also of the portable type and therefore suitable for making an aspiration from drums . Background art

Multiple pumps that serve to send and/or aspire a fluid have long been known.

For instance, pumps of the centrifugal type, gear pumps, progressive cavity pumps, lobe pumps, etc., are known.

In the case of gear pumps, two cogwheel-shaped rotors are foreseen that engage between them in a complementary manner and that are conducted in rotation, respectively, by an axis.

The rotation thereof allows to create the aspiration for the fluid.

Such types of pumps, however, present many technical inconveniences .

In particular, they are not capable of aspiring product if they are not previously immersed. In that case, therefore, before starting the pump it is necessary to fill it with the same liquid or fluid to be pumped, otherwise it does not start to aspire.

Further, they are not capable of aspiring a wide range of products having different viscosities, for example starting from low viscosities such as lcSt to high viscosities such as 500cSt or lOOOcSt.

They cannot aspire fluids containing hard solid particles, since these would risk the damage of the pump. Generally, the size of the particle must not be superior to 0,5mm, beyond which the risk to damage the pump exists.

Last, they lack high aspiring capacities and are not capable of aspiring air bubbles or high quantities of gas/air mixed with the liquid.

All these technical inconveniences are generally solved by means of the use of pumps of the hollow disc type.

A hollow disc pump has also been known for some time and bases its functioning principle on a disc-impeller that is pivoted eccentrically on the shaft of the pump.

Figures from 1 to 3 of the prior art show the main components .

In particular, figures 1 and 1A show structurally such type of pump in two exploded views.

The impeller 104 is therefore highlighted, provided with a guiding slot (drop-shaped) inside of which a diaphragm 104' is inserted, fixed to the frame of the pump .

The impeller 104 is provided with an axial pivot on which a classic rotating compass 113 is bound. The compass 113 couples with the compass 106. The compass 113 can therefore rotate internally with respect to the compass 106 inside of which it is inserted. A shaft 105 is foreseen conducted in rotation by a classic electric engine. The shaft 105 terminates with a widened cylindrical head on which a seat 105' is obtained, in general by milling, inside of which the compass 106, a support cradle 110 (defined cup 110 in technical jargon) and an underlying spring 111 are inserted. The compass 106, and therefore the axis of the impeller 104, rest on the cradle 110.

Precisely because the cradle 110 rests on a spring, the compass 106 (and therefore the impeller) has a possible transversal excursion (therefore a possible translation) along the lodging 105' . The spring tends to keep the compass 106 in the lifted position of figure 2 and figure 3 but, nevertheless, during the rotation of the impeller such compass has also the possibility of translating transversally with respect to the axis of the shaft 105 of a pre-determined quantity in the direction of arrow indicated in figure 3. This takes place when on the compass, and therefore on the impeller, acts a force that exceeds the one exerted by the spring, therefore bringing this last one to compression. This serves to allow a variation of eccentricity of the impeller to allow the passage of impurity of a pre-determined size without the risk of breakages.

The impurity that tends to pass between impeller and seat 120 of the impeller, during its passage, generates a force on the impeller which can vary its eccentricity.

Figure 1A shows in a clearer manner also the cylindrical seat 120 of the pump inside of which the impeller rotates eccentrically to create the aspiration and to which the opening of aspiration and of delivery converge .

The sequences of figures from 4 to 6 show rotation phases of the impeller during its normal functioning, while figure 7 shows the translation of the entire impeller to allow the passage of a present impurity, highlighting the compression of the spring and the variation of eccentricity (it is noted, in fact, that the impeller moves away from the wall of the cylindrical seat 120) .

The sequence of the figures 4-6 shows the roto- translation of the impeller that is kept adherent to the wall of the cylindrical seat 120 where inserted because fixed to the shaft in an eccentric manner, thus creating an aspiration in the direction of the arrows. During its rotation, the diaphragm binds such impeller in such a way as to have in combination to the rotation around the axis of the shaft also an oscillating motion along the direction of the diaphragm. The diaphragm constitutes, therefore, a glyph or slider.

Figure 7 shows the compression of the spring to allow the impeller to move apart from the wall of the seat where lodged for the passage of a sphere of impurity (the while ball) . Once the passage of the impurity has been completed, the spring takes the impeller back in adherence to the wall.

Such type of pump has different advantages:

It is self-priming (that means that it is able to detect fluid from a lower level without the aid of a supplementary pump placed at the level of the liquid that initiates the aspiration) ;

It is reversible (it can work in both senses of rotation) ;

- It guarantees an elasticity of the impeller (it permits the adaptation to all viscosities and the passage of solid particles of big size) ;

It works at a low rotation speed (which means it is suitable for the transfer of high-viscosity fluids).

Nevertheless, such types of pumps, as described, have a system to allow the translation of the impeller (that is spring, cup and seat on the shaft) that results to be complex and that, above all, renders a reduction of size of the pump to less than a certain limit difficult. In accordance with the known art, therefore, the pumps cannot be realized of less than a certain size and are not portable. The fact that they are not portable impedes or renders anyway difficult their use to aspire fluids from drums since it would be necessary to transport the drums in the areas where such pumps are fixed.

It is therefore often necessary to use such types of pumps which, as said at the beginning, may be not idoneous for the fluid to aspire/send.

Further, in accordance with the known art described, it is necessary a complex manufacturing of milling on the shaft to allow to lodge the cup and the spring in it. Such manufacturing, above all, weakens the shaft.

Disclosure of invention

It is therefore the aim of the present invention to realize an assembly for generating the aspiration/push of a fluid in a hollow disc pump (1), which solves said technical inconveniences.

In particular, it is the aim of the present invention to provide an assembly that has a roto-translation system of the impeller that results to be constructively simple, simplifying structurally the pump and reducing the risk of failures and malfunctionings .

It is also the aim of the present invention to provide an assembly in which the roto-translation system used allows a miniaturization of the pump, rendering it of the portable type, in such a way that it can be transported easily to make aspirations also from drums.

These and other aims are thus reached with the present assembly to generate the aspiration/push of a fluid in a hollow disc pump (1), in accordance with claim 1.

Such assembly comprises:

An impeller (9);

A rotating shaft (3) ; Means (4, 5, 30, 36, Fr) to connect eccentrically the impeller (9) to the rotating shaft (3) with a variable eccentricity .

In accordance with the invention, said means (4, 5, 30, 36, Fr) comprise a guiding hole (Fr) obtained transversally in the rotating shaft (3) and an annular element (30) suitable for connecting with the impeller (9) and of such internal diametrical opening (30') that the rotating shaft (3) couples inside of it with a pre- determined clearance (d) in at least one direction.

In this way, thanks to such play, the annular element can arrange eccentrically with respect to the rotating shaft, varying also its eccentricity, moving in the direction of the play.

Such annular element is provided with a pivot (5) that is inserted slidingly in the guiding hole (Fr) of the shaft and in this way the annular element can move transversally with respect to the shaft of rotation (9) guided by the pivot that slides in the guiding hole, in such a way as to be able to vary its eccentricity.

Elastic means (4) are further foreseen, arranged in such a way as to keep the annular element (30) with a predetermined eccentricity with respect to the rotating shaft.

In this way, when on the annular element a force acts sufficient to exceed the force exerted by said elastic means (for example, in the case of presence of impurities of significant size that are aspired by the impeller) , then the annular element moves transversally in contrast to the force exerted by such elastic means, and guided by the sliding of the pivot in its lodging hole of the shaft, thus varies the eccentricity, allowing the passage of the impurity.

When the impurity has climbed over the impeller, then such force ceases to be exerted and the elastic means then take the eccentric ring back (and therefore the impeller connected to it) in the pre-set initial condition of eccentricity.

In this way, all said technical inconveniences are solved .

This solution with annular element, pivot, spring and transversal hole on the shaft is greatly simpler from the structural point of view with respect to the previous solution.

In fact, a complex manufacturing on the shaft is not necessary but instead a simple passing hole is enough.

The cup is now substituted by a simple pivot.

The use of pivot and spring allows easily to miniaturize to the desired value such components, thus being able to realize pumps also portable, something that at the moment is not feasible in accordance with the pumps of the known art described.

It is naturally also described here a hollow disc pump that uses such assembly as described.

Further advantages can be deduced from the dependent claims.

Brief description of drawings

Further features and advantages of the present hollow disc pump, according to the invention, will result to be clearer with the description that follows of some of its embodiments, made to illustrate but not to limit, with reference to the attached drawings, wherein:

- Figures from 1 to 7 show both from the structural and functional points of view a hollow disc pump in accordance with the known art;

- Figure 8 shows an external axonometric view of the pump in accordance with the present invention;

- Figure 9 shows a section of the pump in accordance with the present invention, to highlight the internal components thereof;

- Figure 9A represents an enlargement of the detail of connection, through the pivot, of the impeller to the rotation axis;

- Figure 10 is a front view of the impeller 9 that is assembled in an eccentric way on the axis;

- Figure 11 shows a further section of the front part (An) shown in figure 8;

- Figure 12 shows a sequence of functioning phases of the present pump;

- Figures from 13 to 16 show axonometrically in an exploded view the components of the pump in accordance with the present invention and describe a disassembly phase of the same for eventual maintenance.

Description of some preferred embodiments

With reference to figure 8 an axonometric view of the pump is described 1 in accordance with the present invention.

With the wording ( Pos ) the back part is indicated where the rotary engine is connected, for example a normal electric engine.

The front part (An ) shows, with the wording (As ) , the aspiration hole and with the wording (Ma) the delivery hole. Basically, through the aspiration hole (As ) the fluid is aspired from the low-pressure area and through the delivery hole (Ma) the fluid is sent in the high- pressure area.

Such type of pump is reversible, therefore the deliveries and the aspiration can invert with respect to those indicated in the figure, by simply inverting the rotation motion of the impeller.

Going further into the descriptive detail of the invention, figure 9 shows a section of the present pump. The figure describes with number 19 the engine interface that is connected to the back part ( Pos ) of the pump in such a way as to transmit the rotation.

To that aim, the rotation axis 3, that is the rotating shaft 3, is foreseen, which is assembled rotatably inside of its lodging seat through ball cushions 12 and relative assembly Seeger rings 13.

It is then foreseen a further seal ring 15 whose function is that of impeding the exit of the liquid pumped.

The impeller 9, as highlighted in the figures, is kept in a position between the bottom of the front body (An) and the shoulder of the back part (Pos) .

In figure 9 it is clear that the back part (Pos) connects to the front part (An ) through common connection bolts 17, in such a way that the two parts can be disassembled between them, allowing the assembly, the disassembly and the maintenance.

Going on with the structural description of the invention, with number 10 is indicated the pin inside of which the rotating axis 19' of the engine (represented with a thin dotted line) is inserted. Such rotating axis of the engine renders the pin integral through a grub screw 18. The pin 10 is, in turn, connected to the shaft 3, which can thus be conducted in rotation through the rotation of the axis 19' of the engine to which it is connected .

Going on with the structural description of the invention, figure 9 shows with number 9 the impeller which is also visible in figure 10 and in the figures from 13 to 16.

The impeller is, as per the known art, the rotating element which, through its rotation generates the aspiration of the fluid that passes from the aspiration towards the delivery.

The impeller foresees a slot 9' that enters in contact with the diaphragm 8, in such a way that the diaphragm guides in the roto-translation the impeller itself, as per the known art.

Figure 9 shows with number 8, in section, the diaphragm that is inserted and that guides the impeller 9 and visible axonometrically in the exploded views from figure 13 to 16.

The section of figure 11 refers to the front part

(An) of the pump and shows very well with number (2.3) the positioning seat of the impeller dimensioned in such a way as to allow the eventual translation thereof (that is an eccentric positioning with further possibility of varying such eccentricity) .

Such lodging seat is naturally equivalent to those of the known art and an axonometric view of the same is highlighted, for example, in figure 1A with number 120.

Always the section of figure 11 highlights, above all, the aspiration area (2.1) (which converges with the hole As of figure 8) and the opening (2.4) through which such aspiration takes place. With number (2.5) the delivery opening is highlighted, which converges with the delivery area (2.2) which terminates with the hole (Ma) of figure 8.

The disc 9, of figure 10, as per the known art, is assembled eccentrically on the shaft since, as highlighted in figure 9, the axis of the shaft 3 is not positioned perfectly aligned with the axis 9'' of the disc. In particular, the longitudinal axis of the shaft 3 is not coinciding with the axis 9'' but is spaced from it.

In accordance with the invention, the solution adopted to render the disc eccentric and, at the same time, portable to vary such eccentricity, foresees now a pivot 5, a spring 4, an eccentric annular element 30 and a simple manufacturing of transversal holing ( Fr ) obtained in the shaft 3.

More in particular, the disc 9 is kept in an eccentric position through an eccentric ring 30, a spring 4 and an eccentric pivot 5 that goes through the shaft 3 transversally .

The eccentric ring 30, as well highlighted in the enlargened figure 9A, is a ring similar to a rotating compass and with an internal diameter greater with respect to the shaft that it receives (it does not block by mechanical interference between the two parts) in such a way that the shaft can fix in it not only in an eccentric way but also with a possible excursion stroke.

The axonometric view of figure 15 shows for clarity purposes such eccentric ring 30 and highlights its internal diameter which is worked according to a more or less elliptical shape. Figure 14 shows the shaft 3 inserted in it in an eccentric way with respect to the central axis of the ring 30 and with an excursion space to vary the eccentricity. Basically, the shaft can slide along the greater axis of such ellipsis forming the internal diameter (30' ) of such ring 30 (see figures 14 and 15) .

A transversal holing is therefore foreseen, made on such eccentric ring, realizing a transversal hole 35 for lodging transversally in it an eccentric pivot 5 and a spring 4 (see figures 9A and 15) .

The section of figure 9, 9A and the axonometric view of figure 14 and 15 show such hole 35 that goes through the ring diametrically and inside of which the spring 4 and the pivot 5 are inserted.

The eccentric pivot forms at one end a shoulder 5' (it would substantially be a widened head like in the case of screws) against which the spring is in contact (see also enlargened figure 9A) . The spring is also placed against the shaft 3 on the opposite side, preferably through a circular shoulder 3' formed around the transversal hole inside of which the pivot penetrates 5.

The pivot is, in turn, rendered integral to the eccentric ring 30 through a Seeger ring 36 that avoids the expulsion thereof through the hole 35 (being precisely pushed by the spring) .

In this way, the assembly pivot 5-spring 4 - eccentric ring 30 are a single integral element that is dragged in rotation by the shaft 3 but that is capable of translating transversally with respect to the shaft, varying its eccentricity.

Figure 9A shows very well the play (d) of possible translation that thus varies the eccentricity.

In particular, the spring 4 pushes and keeps the ring 30 in eccentric position with respect to the axis of the shaft 3. The ring 30 is then inserted in the receiving hole of the impeller which thus results to be misaligned with respect to the longitudinal axis of the shaft 3.

The quantity (d) of initial eccentricity depends on the size of the shaft, length of the pivot, etc., and these are planning choices.

When a force opposed to the spring is applied which exceeds a pre-established threshold, the spring initiates to compress itself, reducing the value of play (d) and therefore varying the eccentricity. When the force is released, the spring takes the impeller back in the initial condition of figure 9A.

The eccentric ring, as said, is inserted in the receiving hole of the impeller (the hole of axis 9' ' of figure 10) with a certain degree of interference, remaining packed between the front part 3 and the back part 2 of the pump. The eccentric ring, with respect to the hole of the impeller where it is inserted, can rotate relatively, in such a way as to acquire the oscillating motion as per the known art through the diaphragm that guides it .

Basically, in accordance with the invention, the realization takes place now of a simple transversal hole in the shaft 3 in the area where the connection with the impeller is foreseen. The shaft is inserted inside of the eccentric 30 in such a way that the hole on the shaft and the hole 35 for the insertion of the pivot-spring package are aligned. At this point, the insertion of the pivot 5 provided with spring 4 takes place, paying attention to blocking the pivot through the application of the stop 36.

In this way, the pivot, through the stop 36, cannot be expelled outside of the lodging hole and remains in position since held by the spring that, on the opposite side, beats against the surface of the shaft.

In this way, the shaft results to be eccentric with respect to the ring 30 to which it is fixed and with such eccentric ring 30 that can move transversally with respect to the shaft of the quantity of compression admitted by the spring 4.

The eccentric ring couples to the impeller that therefore results to be eccentric with respect to the axis of the shaft 3 and with variable eccentricity.

Starting from figure 9A, in case the eccentric ring 30 receives a push force in the direction of compression of the spring 4, the stop ring 36 transmits such push to the pivot that moves in a manner integral to the eccentric ring, compressing the spring .

In use, therefore, the eventual presence of present impurity, as discussed also in the known art, is compensated by a translation of the entire impeller. Such translation is now obtained with the pivot- eccentric system just described.

Figure 12 shows the rotation phases of the impeller to generate the aspiration and highlights with "d" the possible translation distance of the impeller itself to allow the passage of impurity of a pre-determined size (therefore the play "d" of figure 9A) .

In accordance with the invention, such translation distance d is in general of the order of the 5mm but can be varied by choosing adequately the spring, the size of the eccentric ring, the pivot and the diameter of the shaft 3.

As said, these are planning variables.

Figures from 13 to 16 show a disassembly sequence. The assembly sequence is exactly inverse to that of disassembly that is described below.

As per figure 13 the separation of the front part An) from the back part (Pos) takes place to proceed with the removal of the diaphragm , of the impeller and of the seal gasket.

As per figure 14, the removal of the seal ring 36 of the pivot 35 takes place, to then remove pivot and spring.

At this point, as per figure 15, the eccentric ring 30, the relative oil retainers foreseen and the Seeger rings can be removed.

Last, as per figure 16, the removal of the cushions and the extraction of the shaft can take place.

In theory, in the hollow disc pumps already existing it would be possible to substitute the shaft-impeller connection assembly with the present system described, in such a way as to modify them in accordance with the invention .

Claims

1. An assembly to generate the aspiration/push of a fluid in a hollow disc pump (1), said assembly comprising:

An impeller (9);

A rotating shaft (3);

Means (4, 5, 30, 36, Fr) to connect eccentrically the impeller (9) to the rotating shaft (3) with a variable eccentricity;

Characterized in that said means comprise a guiding hole (Fr) obtained transversally in the rotating shaft (3) and an annular element (30) suitable for connecting with the impeller (9) and of such an internal diametrical opening (30' ) that the rotating shaft (3) couples into said internal diametrical opening (30' ) eccentrically with respect to the axis of the rotating shaft, said annular element being provided with a pivot (5) that is inserted slidingly in said guiding hole of the shaft in such a way that the annular element can move transversally with respect to the rotating shaft (9) guided by the pivot that slides in the guiding hole in such a way as to be able to further vary its eccentricity, and wherein elastic means (4) are foreseen arranged in such a way as to keep the annular element (30) with a pre-determined eccentricity (d) which varies when on the annular element (30) acts an eventual sufficient force to exceed the force exerted by said elastic means.

2. An assembly, as per claim 1, wherein the guiding hole (Fr) is passing through the diameter of the rotating shaft (3) .

3. An assembly, as per claim 1 or 2, wherein the pivot (5) is inserted in a hole (35) that goes through the annular element (30) diametrically.

4. An assembly, as per claim 3, wherein the pivot (5) is blocked inside the hole (35) on one side by a stop element (36) and on the opposite side by said elastic means .

5. An assembly, as per claim 4, wherein said stop element (36) is a Seeger ring.

6. An assembly, as per one or more of the preceding claims, wherein said elastic means (4) are in the form of a spring (4) interposed between the external surface of the rotating shaft and a shoulder (5') obtained in the pivot (5) .

7. An assembly, as per claim 6, wherein the spring is concentric to the pivot.

8. An assembly, as per claim 6 or 7, wherein the spring is a compression spring.

9. An assembly, as per claim 1, wherein the internal diametrical opening (30') has an ellipsoidal form.

10. An assembly, as per one or more of the preceding claims, wherein said internal diametrical opening (30') is such that the rotating shaft (3) couples eccentrically with respect to the axis of the rotating shaft with a pre-determined play (d) in at least one direction .

11. A hollow disc pump comprising an assembly for generating the aspiration/push of a fluid in accordance with one or more of the preceding claims from 1 to 10.

12. A method for modifying a hollow disc pump, said method foreseeing the disassembly phase of the rotating shaft that drags the impeller and the disassembly of the impeller and the substitution with an assembly as per one or more of the preceding claims from 1 to 10.