EP3322898A1 - A pump of the interchangeable type - Google Patents

Abstract

The present invention concerns a pump comprising rotation means (10', 20', 42, 43, 52, 53) to generate the aspiration/push of a fluid. In accordance with the invention, such rotation means are interchangeable in such a way as to be able to switch from a configuration of lobe pump to a configuration of screw pump and vice-versa.

Description

A PUMP OF THE INTERCHANGEABLE TYPE

Technical field

The present invention refers to the technical field relative to the pumps for the sending/aspiration of a fluid.

In particular, the invention refers to a particularly versatile pump.

Background art

Pumps that serve to send and/or aspire fluid have long been known.

For instance, currently in the market there exist both Two-Screw Pumps (Volumetric) and Lobe Pumps (Volumetric) .

A pump is defined as volumetric when, as it is well known, it generates a push or an aspiration through a variation of volume.

These two types of pumps have various applications in common and can function with satisfying results in many cases different one from the other, in particular food and sanitary applications (Food & Beverage

Hygienic/Sanitary) . There exist anyway applications in which Two-Screw Pumps have better performances than Lobe Pumps, and vice-versa.

Just as a way of example, we indicate that:

The Lobe Pump transfers the product in a pulsating way, and this is not well seen in most food applications: The pulsations cause vibrations, inconstant flow rates, difficulty in the measurement of the fluid and in the bottling. The Screw Pump, instead, lacks pulsations, and this feature is always more satisfying in food applications. Further, the Lobe Pump is not capable of rotating at high speeds to be able to make the CIP (Cleaning in Place) ; therefore, another pump has to be used (for example, a centrifugal pump), which is capable of producing higher speeds of the water flow and chemical products that make the CIP. In that sense, the Screw Pump, instead, is capable of rotating both at low and high speeds, and is therefore capable of pumping a great variety of products (of various viscosities) and of making the CIP at 2000-3000 rpm.

The Lobe Pump is capable of pumping soft solid products (for instance, fruit or fruit pieces), also of big size, dissolved in a liquid; the Screw Pump, in order to be able to pump the same sizes of solids, has to be over-dimensioned with respect to the loads requested; further, the Screw Pump can damage a small percentage of the solids, while the Lobe Pump cannot; the Lobe Pump has the further advantage of being able to pump these solids also in liquids of medium viscosity, a feature that is instead more limiting in the screw pumps.

The Lobe Pump, when it is operated at a low number of turns, can pump liquids very sensitive to shear forces, such as: diced fruit/vegetables , curd, fresh cheeses; the Screw Pump imposes shear forces that are slightly worse.

From the above it is clear that according to the applications one or the other type of pump could be more idoneous .

Structurally, a screw pump foresees two screws enclosed by a body, placed in a parallel way between them and coupled in such a way that between them they can engage, rotating in a synchronized manner. The reciprocal rotation and the engagement causes a translation of the entire volume comprised between the crests of the screws and the body that encloses them, causing the movement of the fluid according to a direction that depends on the sense of rotation.

The lobe pump substitutes the two screws coupled between them with two lobe rotors (not in contact between them) , whose rotation causes the movement of the fluid.

It is therefore usual to find that, in the same system, there exist Two-Screw Pumps for certain applications and Lobe Pumps for others.

Naturally, the need to operate with two pumps of different nature, according to the needs, creates not a few inconveniences .

For example, the first one is certainly that relative to the costs, because it is necessary to purchase two pumps of different nature, also when, for instance, the number of uses of one of the two types of pumps is very reduced with respect to the number of uses of the other pump. In any case, it is anyway necessary to foresee both types of pumps, the whole with an increase in the management costs.

Further, the need to have two pumps different one from the other implies greater maintenance costs and naturally they occupy a lot of space, resulting to be bulky .

Another disadvantage derives from the fact that the Lobe Pump, not being able to be used as a pump for the CIP (Cleaning in Place) , has to be coupled to a centrifugal pump that is used exclusively for the CIP itself. In that sense, almost always, it is even necessary to have even three types of different pumps, with huge additional costs .

Disclosure of invention

It is therefore the aim of the present invention to realize a pump that solves said technical inconveniences.

In particular, it is the aim of the present invention to provide a pump that results to be versatile, being able to adapt itself easily and quickly to the needs, and thus being able to serve as a screw or lobe pump according to the needs .

It is therefore the aim of the present invention to provide a pump that results of reduced encumbrance, though serving as screw or lobe pump, and that results to be above all much more economical.

These and other aims are thus reached with the present pump in accordance with claim 1.

Such a pump foresees rotation means (10', 20', 42, 43, 52, 53) that, through the rotation thereof, generate the aspiration/push of a fluid.

In accordance with the invention, said rotation means are interchangeable in such a way as to be able to pass from a lobe pump configuration to a screw pump configuration and vice-versa.

In such a manner, always with the same pump, one can quickly switch, according to the need, from a lobe pump configuration to a screw pump configuration and vice- versa. In this way, all said technical inconveniences are solved since the pump becomes very versatile, there is a saving in encumbrances and costs.

Further advantages can be deduced from the dependent claims .

Brief description of drawings

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

- Figure 1 shows the pump in accordance with the invention, wherein the front part is interchangeable, that is that it can be every time removed and substituted, in such a way as to be able to have, when needed, a lobe pump or a screw pump;

- Figure 2, figure 3 and figure 4 are views relative to the back part of the pump to which the interchangeable parts are connected;

- Figure 5 is a further section of the back part;

- Figures 6 and 7 show in detail the front part relative to the solution with two screws;

- Figures 8, 9 and 10 show in detail the front part relative to the solution with lobes.

Description of some preferred embodiments

With reference to figure 1 a pump is represented as per the present invention which, as better clarified below, allows to interchange a front part relative to the lobes or screws, therefore rendering it versatile.

Figure 1 shows such a pump in which there is a fixed back part 2, better described below, and a front part (3', 3' ' ) , which is configured in such a way as to result interchangeable, in the sense that it can be substituted so that the pump results to be, according to the needs, a lobe or a screw pump.

Figure 1 in fact shows in a cross-section the arrangement of the screw solution and in a further cross- section the lobe solution.

Figure 2 highlights the back part in an axonometric view .

Figure 2 shows the two attachment holes (10, 20), where the rotation axes are inserted and/or exit on which, in an interchangeable manner, the lobe or screw system assembles .

In particular, as shown in figure 3, in the two relative holes (10, 20) rotation axes (10', 20') remain inserted perpetually on which the lobes or the screws are assembled .

To that purpose, in the enlargened view of figure 4, the tabs 11 are highlighted that render integral to the rotation shaft the sleeve forming the screw or the lobe wheel. The sleeves are inserted slidingly on the shaft in such a way that the tabs are inserted in a specific groove and so that said sleeves rotate integrally with the shaft.

Figure 5 shows for completeness a section of the back part and highlights the two rotation axes (10', 20') that emerge externally from it and connected to the axes (100, 110) .

Such axes (10' , 20' ) can be separable from the axes (100, 110) or be in a single piece.

Figure 5 shows, naturally, the support rotation bearings 130 for the rotation of the shafts.

Two back dented wheels (140, 140') engage between them making that the two axes (100, 110) rotate between them in a synchronized manner. In that sense, a dented wheel (that numbered with number 140) is conducting, while the other is the conducted one. In fact, in correspondence of the conducting wheel 140 a back extension 110' of the axis 110 is foreseen, configured to connect to a conventional rotary engine (not shown in figure for descriptive simplicity) .

Figure 6 shows in a section the front part provided with two screws (41, 42) .

In particular, the elements 41 and 42 are two sleeves whose external form is that of screw and that are inserted slidingly on the shaft and dragged in rotation through the tab 11 arranged on each shaft.

Anteriorly, the screw sleeves are blocked through nuts 50 in position and posteriorly they go in contact against a stop 51 in such a way as to result to be well packaged on the relative shaft. The body (46, 46') is then fixed and a front cover 43 encloses the body and seals. It is further present an inlet/outlet hole for the fluid.

Enlargened figure 7 shows the three parts (43, 46, 46') assembled among them with the aspiration/exit openings (44, 44') of the fluid. The sleeves (41, 42) are further highlighted with the form of screw and that are inserted slidingly and fixed to the shafts.

Figure 8, instead, shows a section of the lobe solution, which is substantially similar to that of screw described above.

In this case, the sleeve with the form of screw is substituted with a sleeve (52, 53) with the form of lobe wheel. In fact, therefore, two lobe wheels (52, 53) are inserted slidingly each one on a shaft (10', 20') and constrained at rotation through the tab mentioned above.

The shoulder mentioned above on one part and screw or nut on the front part make that the two lobe wheels are well packaged to the shaft.

Figure 9 shows the openings (56, 57) for inlet/outlet of the fluid and the two lobe wheels engaged between them.

The tabs are arranged in such a way that the two lobe wheels engage between them correctly as per figure 9.

Figure 10, similarly to the screw solution, shows the closing body composed of a front plug 61 and a lateral part 62 that forms together with the plug the volume of containment of the fluid.

In use phase, therefore, such an interchangeable pump functions in the following way.

In case there has to be a shift from a screw pump to a lobe pump, assuming that the screw pump has been assembled, it is enough to remove the body (43, 46, 46' ) of the screw pump in such a way as to bring to light the axes (10' , 20') on which the two screw sleeves (41, 42), are assembled, as shown in figure 7. Once the sealing screws foreseen for the fixing of the part of body are disassembled, the front plug 43 and the two cylindrical parts (46, 46' ) can be removed, thus bringing to light the two sleeves forming the screws. At this point the front nuts 50 (see figure 6) are disassembled and the two sleeves (41, 42) slip out.

In their place the sleeves (52, 53) forming the lobe wheels are inserted slidingly (see figure 8) and are fixed with the bolts foreseen. Last, the front body (61, 62) is assembled .

In a simple and quick way, therefore, we have switched from a screw pump to a lobe pump.

The inverse operation for the passage from the lobe pump to the screw pump is naturally identical and not repeated here for simplicity purposes.

The back engine that connects to the axis 110' will conduct the axes at the rotation speed, desired.

In a possible variant of the invention, nothing impedes that the axes (10', 20') are detachable, in part, in more than one piece, or completely, from the back part 2 and therefore the insertion of axes already provided with screw or lobe sleeve can be foreseen, or to allow the insertion of sleeves of different axial sizes.

There can exist also variants of the invention that comprise other common devices of transmission of pair, such as keys, splines, etc.

Claims

1. A pump (1) comprising rotation means (10', 20', 42, 43, 52, 53) to generate the aspiration/push of a fluid and characterized in that said rotation means are at least in part interchangeable in such a way as to be able to switch from a configuration of lobe pump to a configuration of screw pump and vice-versa.

2. A pump, as per claim 1, wherein a back part (2) is foreseen, said rotation means comprising two rotation axes (10', 20') exiting from said back part (2).

3. A pump, as per claim 2, wherein said rotation means further comprise a pair of sleeves (42, 43) with the external form of a screw and a pair of sleeves (52, 53) with the external form of a lobe and configured to be able to be fixed to said rotation axes (10', 20') in an interchangeable manner.

4. A pump, as per claim 3, wherein said sleeves (42, 43;

52, 53) are insertable slidingly on said rotation axes (10' , 20' ) .

5. A pump, as per claim 1, wherein said rotation means comprise two pair of rotation axes (10', 20') and of which one pair with the external form of a screw and one pair with the external form of a lobe, said axes being insertable in the back part (2) in an interchangeable manner.

6. A pump, as per one or more of the preceding claims, wherein a disassemblable body (43, 46, 46'; 61, 62) is foreseen, arrangeable to close the rotation axes (10', 20' )

7. A pump, as per claim 6, wherein the body foresees a front plug (43, 61) and a cylindrical part (46, 46'; 62) connected to the back part (2).

8. A pump, as per claim 6 or 7, wherein the body is provided with openings (44, 44'; 56, 57) of inlet/outlet for the fluid.

9. A pump, as per one or more of the preceding claims, wherein the back part (2) foresees a rotary engine.