Patent Description:
In particular, the invention relates to a device for determining the direction of rotation of the impeller of a pump.

As well known, the direction of rotation of an impeller inside a centrifugal pump is of fundamental importance to ensure maximum compression efficiency.

However, in the case of pumps powered by three-phase electric motors in alternating current, it may happen that this direction of rotation is incorrect due to an involuntary inversion of the phases during connection to the power supply. This aspect can be particularly burdensome in terms of time for the operator, as most of the time it is possible to realize that the direction of rotation is wrong only after having completed the installation of the system.

Therefore, it is extremely useful to provide the operator with an indicator that allows you to check the right direction of rotation of the impeller when connecting to the power supply.

A first example of such devices is shown in <CIT>, in which the fan cover provides a tab hinged to it and pushed by the air flow generated by the impeller. In the event that the impeller rotates in the wrong direction, the tab is pushed towards a stop which causes it to touch the impeller blades, causing a noise used as a sound signal for incorrect rotation.

However, this system has first of all the drawback of severe wear of the tab and, secondly, the difficulty for an operator to receive the sound signal within noisy environments, very frequent in this sector.

To overcome these drawbacks, <CIT> describes a device capable of providing a visual and contactless signal between the indicator and the impeller blades. In particular, this indicator device includes a tab arranged near the impeller in such a way that the air flow can move it to a first position in the event of a correct direction of rotation and to a second position in the event of an incorrect direction of rotation. A shaft connected to this tab then transmits the assumed position to an element external to the fan cover, allowing the operator to check the direction of rotation of the impeller.

However, this solution also has various drawbacks. Firstly, the presence of a transmission shaft, in a device of necessarily reduced dimensions and subject to strong vibrations, can result in a structurally weak point of the indicator, with low reliability over time and high probability of fatigue failure. Furthermore, in order to be able to use it on existing pumps, in this solution the indicator is completely separate from the fan cover, facilitating its loss during transport and installation of the system. A further disadvantage lies in the fact that, once the indicator is installed in the fan cover and having used it for a first test, the indicator is not easily accessible for a second use, requiring the disassembly of the entire fan cover. A further example of an indicator is shown in <CIT>.

It is therefore a feature of the present invention to provide a fan cover for protection of an impeller which allows the direction of rotation of the impeller to be viewed without the need for installation of external components.

It is also a feature of the present invention to provide such a fan cover which comprises an indicator not subject to severe wear and with high reliability over time.

It is also a feature of the present invention to provide such a fan cover which comprises an indicator which can be easily removed from the fan cover itself and which can be reused or reset for tests subsequent to the first.

It is also a feature of the present invention to provide such a fan cover that includes an indicator that can be easily locked in its position during transport and/or during full operation of the pump once the installation phase is completed.

These and other objects are achieved by a fan cover for protection of an impeller, said impeller arranged to rotate about a rotation axis x producing a consequent fluid flow, said fan cover comprising:.

With respect to the solutions of the prior art, the present invention integrates the indicator into the fan cover itself, requiring fewer components and increasing overall reliability.

Advantageously, said indicator comprises an indication portion integrally connected to said planar portion and said indicator is inserted, in use, in said through hole with said indication portion at least partially external to said inner volume, in such a way that outside of said protection wall is visible if said indicator is in said first position or in said second position.

Alternatively, said indicator is arranged entirely within said inner volume and said or each through hole is adapted to show outside of said protection wall if said indicator is in said first position or in said second position.

This solution allows to have the indicator completely inside the volume of the protection wall, avoiding possible damage due to impacts of the protection wall itself.

In particular, said indicator is, in use, arranged to rotate with respect to said protection wall to move to said first position or to said second position.

In particular, the axis x' around which the indicator rotates is parallel to the axis x around which the impeller rotates.

Alternatively, the axis x' is orthogonal to the axis x.

Advantageously, said protection wall comprises a single through hole and said indicator is, in use, rotatably connected to said protection wall at said through hole.

This solution allows to reduce the exposed area and to fully cover the opening light by means of the indicator pivot pin.

Alternatively, the protection wall comprises a first through hole and a second through hole.

Advantageously, the indicator is, in use, rotatably connected to the protection wall in a position substantially equidistant from the through holes, so that the first through hole shows the first face when the indicator is positioned in the first position and the second through hole shows the second face when the indicator is in the second position.

Advantageously, transparent protective plates are provided in correspondence with the through holes.

In particular, said indicator is, in use, arranged to translate with respect to said protection wall to move to said first position or to said second position.

Advantageously, said indicator is removably inserted in said through hole.

In particular, a locking means is provided arranged to prevent the rotation of said indicator.

Advantageously, said locking means comprises a plug configured to be inserted in said through hole to prevent said indicator from escaping from said through hole, said plug being suitably shaped to prevent the rotation of said indicator.

Advantageously, said first face is visually distinguished from said second face.

For example, the first and second faces have different colours, or identifying marks, or writings.

According to another aspect of the invention, it is also claimed a motor pump arranged to increase the pressure of a fluid, said motor pump comprising:.

The invention will be now shown with the following description of some exemplary embodiments, exemplifying but not limitative, with reference to the attached drawings in which:.

In <FIG> are schematically shown some possible embodiments of the fan cover <NUM>, according to the present invention, for protection of an impeller <NUM> arranged to rotate about a rotation axis x.

In particular, the fan cover <NUM> comprises a protection wall <NUM> defining an inner volume <NUM> inside which, in use, the impeller <NUM> resides. In particular, the protection wall <NUM> comprises a front face <NUM>' and a lateral face <NUM>".

The fan cover <NUM> further comprises an indicator <NUM> comprising a planar portion <NUM> having a first face 125a and a second face 125b. In particular, the indicator <NUM> is arranged, in use, at least at one through hole <NUM> present in the protection wall <NUM> and is located in such a way that the planar portion <NUM> is arranged at least partially inside the inner volume <NUM>. In particular, the through hole <NUM> can be located on the lateral face <NUM>" or on the front face <NUM>'.

This way, when the impeller <NUM> rotates in a first direction, the flow generates a pressure on the first face 125a moving the indicator <NUM> in a first position, while, when the impeller <NUM> rotates in a second direction, the flow generates a pressure on the second face 125b moving the indicator <NUM> in a second position.

As described below, the present invention provides different solutions that allow to view from the outside whether the indicator <NUM> is in the first position or in the second position.

In this way, an operator who carries out the installation, for example, of an electric pump, can check that the direction of rotation of the impeller pump is correct, as soon as the electric motor connected to it is connected to the power supply, avoiding the risk of installing the entire system with an incorrect direction of rotation of the impeller.

Furthermore, all the embodiments of the present invention provide that the indicator <NUM> is substantially integrated in the fan cover <NUM>, requiring fewer components than the prior art and thus increasing the overall reliability.

In particular, in the embodiments of <FIG>, the indicator <NUM> is adapted to rotate with respect to the protection wall <NUM>. This way, the indicator <NUM> can rotate about its own axis as a consequence of the air flow generated by the impeller <NUM>.

Therefore, when the impeller <NUM> rotates clockwise (as in <FIG>), the air flow generates a pressure on the first face 125a making the indicator <NUM> rotate counterclockwise, and, when the impeller <NUM> rotates counterclockwise, the air flow generates pressure on the second face 125b causing the indicator <NUM> to rotate clockwise.

Furthermore, the indicator <NUM> is inserted inside the through hole <NUM> in such a way that an indication portion <NUM> is external to the protection wall <NUM>. Thus, when the planar portion <NUM> rotates due to the air flow, the indication portion <NUM> rotates integrally, allowing to see from the outside of the protection wall <NUM> whether the indicator <NUM> is in the first position or in the second position, allowing to know the direction of rotation of the impeller <NUM>.

In particular, the indication portion <NUM> can have visually distinguishable faces, for example of different colours, to facilitate control by the operator.

In particular, the indicator <NUM> can be pivotally connected to the protection wall <NUM>, for example by means of a hinge, or it can be disposed in a removable manner in a circular seat.

Advantageously, both solutions shown in <FIG> provide that the lateral edges <NUM> of the through hole <NUM> prevent the indicator <NUM> from rotating beyond a predetermined angle.

With reference to <FIG>, in one embodiment the invention provides that the indicator <NUM> is completely internal to the protection wall <NUM>. In this embodiment, moreover, the protection wall <NUM> comprises two through holes <NUM> and <NUM>', in such a way that the first through hole <NUM> shows the first face 125a outward when the indicator <NUM> is positioned in the first position and the second through hole <NUM>' shows the second face 125b when the indicator <NUM> is positioned in the second position.

This embodiment therefore allows not to have an indication portion <NUM> that protrudes from the perimeter of the protection wall <NUM>, avoiding possible damage to the indicator <NUM> due to impacts of the fan cover, for example during transport.

With reference to <FIG>, in one embodiment the indicator <NUM> is not hinged to the protection wall <NUM> but is constrained to translate with respect to it to move to the first or second position.

This embodiment is advantageous in terms of reliability, since it avoids the presence of hinges which can potentially be damaged due to accidental impacts.

With reference to <FIG>, in one embodiment the indicator <NUM> is rotatably connected to the protection wall <NUM> in correspondence with the indication portion <NUM> and it has an axis of rotation x' orthogonal to the axis of rotation x of the impeller <NUM>. In this embodiment, the planar portion <NUM> passes through the through hole <NUM> until it reaches the fluid flow present in the internal volume, as shown in <FIG>.

In this way, when the fluid flow generates a pressure on one of the two faces 125a, 125b, the indication portion <NUM> is made to rotate around the axis x', showing externally whether the indicator <NUM> is in the first or second position.

With reference to <FIG>, in a further embodiment the through hole <NUM> is arranged on the front face <NUM>' of the protection wall <NUM>, instead of on the lateral face <NUM>", and it is crossed by the indicator <NUM>, in such a way that the indication portion <NUM> is arranged on the front face <NUM>' itself. Similarly to the embodiments of <FIG> and <FIG>, the indicator <NUM> is rotatably connected to the protection wall <NUM> and is able to rotate around an axis parallel to the axis of rotation x of the impeller <NUM>.

This embodiment allows to better protect the indication portion <NUM> and not to have to make openings on the surface of the lateral face <NUM>".

In <FIG> an application solution is shown of an embodiment of <FIG>.

In particular, this embodiment provides that the indicator <NUM> is not integrally connected to the protection wall <NUM> and is disposed, in use, inside the through hole <NUM> in a removable manner, so as to be able to rotate with respect to the protection wall <NUM> thanks to the pins <NUM>'.

Furthermore, with reference to <FIG> and <FIG>, in this embodiment a plug <NUM> can be provided, which can be placed in correspondence with the through hole <NUM> and suitably shaped to prevent rotation of the indicator <NUM>.

In this way, when the fan cover <NUM> is transported or handled, the plug prevents both the exit of the indicator <NUM> from the through hole <NUM> and the unwanted rotation of the same, which could cause wear and damage.

Claim 1:
A fan cover (<NUM>) for protection of an impeller (<NUM>), said impeller (<NUM>) arranged to rotate about a rotation axis x producing a consequent fluid flow, said fan cover (<NUM>) comprising:
- a protection wall (<NUM>) defining an inner volume (<NUM>) arranged, in use, to house said impeller (<NUM>), said protection wall (<NUM>) comprising a front face (<NUM>') and a lateral face (<NUM>");
- an indicator (<NUM>) comprising a planar portion (<NUM>) having a first face (125a) and a second face (125b);
said fan cover (<NUM>) characterized in that said protection wall (<NUM>) comprises at least one through hole (<NUM>,<NUM>') located on said front face (<NUM>') or on said lateral face (<NUM>"),
and in that said indicator (<NUM>) is arranged, in use, at said through hole (<NUM>,<NUM>') with said planar portion (<NUM>) at least partially within said inner volume (<NUM>), in such a way that, when said impeller (<NUM>) rotates in a first direction, said fluid flow generates a pressure on said first face (125a) moving said indicator (<NUM>) in a first position and, when said impeller (<NUM>) rotates in a second direction, said fluid flow generates a pressure on said second face (125b) moving said indicator (<NUM>) in a second position.