Technical Field

The present invention relates to a liquid/solid separating device, especially for the treatment of a mixture to be purified.

Background Art

Within the present treatise, the expression“mixture to be purified” means a heterogeneous mixture of a solid suspended in a liquid.

An example of a mixture to be purified is, e.g., wastewater that needs to be separated from any solid residues and purified before it can be returned to the environment.

Wastewater treatment consists of a succession of several purification phases through which, from a mixture of water and contaminants, purified water is obtained.

This treatment generally comprises a first phase of separation of any suspended or floating solid residues in the mixture to be purified.

The aforementioned phase is carried out in special systems by means of pumps capable of sucking the mixture to be purified and, afterwards, sending it to further systems for subsequent treatments.

The pumps usually used for this purpose are shredding pumps provided with an inlet mouth for the mixture to be purified and with an open type impeller, responsible for both suction and shredding of any aggregated solid residues.

In particular, in the shredding pumps of known type, the impeller is located in a backward position with respect to the inlet mouth, so that the heterogeneous mixture can be efficiently conveyed to the impeller itself, even in the case of large solid residues.

The inlet mouth is usually positioned downwards so as to be constantly submerged and avoid possible air suction, which would jeopardize the correct operation of these pumps.

Therefore, the shredding pumps of known type are submersible pumps that are placed on or near the bottom of the treatment tanks.

However, for this very reason, the submersible shredding pumps are not able to effectively remove any solid residues which are floating at the point where the free surface of the mixture to be purified is located, with the risk of impairing the effectiveness of the entire purification treatment.

In order to allow an effective removal of the floating solid residues, liquid/solid separating devices are known which are provided with an external shredding pump, the inlet mouth of which is connected through a connecting pipe to a supply element submerged in the mixture to be purified.

In particular, the supply element is kept close to the free surface of the mixture to be purified by means of floating elements.

In this latter type of liquid/solid separating devices, however, the connecting pipe of the supply element to the shredding pump can be easily obstructed, with the consequent need to interrupt the treatment to free the pipe itself; this is even more frequent in the presence of sticky solid residues that tend to stick together to form voluminous aggregates.

A further drawback of such liquid/solid separating devices is that they often operate irregularly because, especially during the treatment of very dense mixtures to be purified, the floating elements are not able to correctly position the supply element below the free surface, with the risk of possible air suction. Description of the Invention

The main aim of the present invention is to devise a liquid/solid separating device that effectively removes any solid residues which are floating at the point where the free surface of a mixture to be purified is located.

Another object of the present invention is to devise a liquid/solid separating device that allows adequate conveying of the solid residues to the shredding pump.

A further object of the present invention is to allow a correct positioning of the supply element below the free surface of the mixture to be purified based on the density of the latter.

Another object of the present invention is to devise a liquid/solid separating device which allows overcoming the aforementioned drawbacks of the prior art in the ambit of a simple, rational, easy, effective to use and low cost solution. The objects set out above are achieved by the present liquid/solid separating device, having the characteristics of claim 1.

Brief Description of the Drawings

Other characteristics and advantages of the present invention will be more evident from the description of a preferred, but not exclusive, embodiment of a liquid/solid separating device, illustrated as an indication, but not limited to, in the attached tables of drawings in which:

Figure 1 is an axonometric view of the liquid/solid separating device according to the invention;

Figure 2 is an exploded view of a detail of the present invention;

Figure 3 is a view of a detail of an embodiment of the present invention;

Figure 4 is a view of a detail of a further embodiment of the present invention; Figure 5 is an axonometric view of the present invention in a mode of use.

Fmbodiments of the Invention

With particular reference to these figures, reference numeral 1 globally indicates a liquid/solid separating device.

The liquid/solid separating device 1 comprises at least one shredding pump 2 adapted to shred solid residues 3 floating at a free surface 4 of a mixture to be purified 5.

The shredding pump 2 is provided with at least one inlet mouth 6 of the mixture to be purified 5 and is positioned inside a treatment tank 7.

In particular, the shredding pump 2 is of the type of a submersible pump, with open and backward impeller, which makes it possible to suck in and shred, at the same time, the aforementioned solid residues 3, or any of their aggregates, present in the mixture to be purified 5.

The latter, during treatment, comes out of the shredding pump 2 through an outlet connection 8, by means of which it can be sent to an additional treatment plant.

In addition, the device 1 comprises at least one supply element 9 defining at least one entry port 10 of the mixture to be purified 5 and adapted to convey the latter towards the inlet mouth 6 of the shredding pump 2. The supply element 9 is positioned in the proximity of the free surface 4 and allows the adequate conveying of the solid residues 3 floating on the mixture to be purified 5.

In particular, the supply element 9 is arranged so that the entry port 10 is below the free surface 4 and in the immediate vicinity thereof.

During suction, a swirling flow is generated on the aforementioned free surface

4 which directs the solid residues 3 towards the entry port 10.

Conveniently, the device 1 comprises at least one safety element 11 associated with the supply element 9 and located in the proximity of the entry port 10.

As shown in Figures 3 and 4, the safety element 11 is placed on top of the free surface 4 and prevents foreign elements from entering accidentally the supply element 9 and, therefore, the shredding pump 2.

In addition, the device 1 is provided with floating means 12 adapted to position and maintain the supply element 9 below the free surface 4 of the mixture to be purified 5.

Advantageously, the floating means 12 comprise at least two adjustable floating elements 13, each provided with at least one upper duct 14 for the inlet and/or outlet of a first fluid and with at least one lower duct 15 for the inlet and/or outlet of a second fluid.

In particular, the first fluid is of the type of a gas, e.g. air, while the second fluid is of the type of a liquid, e.g. water.

This way, once the device 1 has been immersed in the mixture to be purified 5, it is possible to modify the weight of the floating elements 13 and, therefore, their flotation level, so as to correctly position the supply element 9 below the free surface 4, based on the real density of the mixture to be purified 5 itself.

In fact, in the case of very dense mixtures, it will be necessary to increase the weight of the floating elements 13, introducing a greater amount of water while, on the other hand, in the case of less dense mixtures, a greater amount of air will be introduced.

This way, the entry port 10 is constantly immersed in the mixture to be purified

5 and there is no risk of unwanted air suction. At least one of either the upper duct 14 or the lower duct 15 is connected to a pumping assembly, not shown in the figures, which allows the first fluid and/or the second fluid to be conveyed inside the floating elements 13.

Both ducts 14 and 15, moreover, can be closed once the desired quantities of first fluid and second fluid have been introduced, so as to maintain the flotation level of the floating elements 13 constant.

According to the invention, the shredding pump 2 is associated with the floating means 12 below the supply element 9 and the inlet mouth 6 is associated with the supply element 9 below the entry port 10.

In other words, the supply element 9 is directly connected to the shredding pump 2 and this particular conformation allows doing without the use of connecting pipes which are easy to be obstructed.

More specifically, the supply element 9 comprises at least one lower portion 16, associated with the shredding pump 2 at the inlet mouth 6, and at least one upper portion 17 defining the entry port 10.

In addition, the supply element 9 has a substantially truncated-cone shape converging from the entry port 10 towards the inlet mouth 6, which allows it to adequately convey the mixture to be purified 5 to the shredding pump 2 and further reduce the risk of obstruction.

In fact, as shown in the figures, the upper portion 17 has a larger diameter than the lower portion 16, which gives the supply element 9 a large passage volume; this allows the solid residues 3 floating on the free surface 4 to be easily sucked in and to avoid the formation of aggregates inside the supply element 9 itself.

In a particular embodiment, shown in Figure 4, the upper portion 17 can also be provided with at least one lateral opening 18 adapted to generate turbulence on the free surface 4 of the mixture to be purified 5.

The lateral opening 18 makes the swirling flow of the free surface 4 more turbulent and, especially in the presence of sticky solid residues 3 prevents these from grouping into bulky aggregates and reduces the adhesion thereof to the treatment tank 7.

Conveniently, the shredding pump 2 is associated with the floating means 12 by interposition of a supporting unit 19.

The supporting unit 19 supports together the floating elements 13 and the shredding pump 2 and is associated vertically sliding with at least one positioning unit 20, at least partially immersed in the mixture to be purified 5. The positioning unit 20 is located inside the treatment tank 7 and is fastened thereto, resting on the bottom of the treatment tank itself.

Conveniently, the supporting unit 19 comprises sliding pins 21 moveable along respective vertical sliding guides 22 defined on the positioning unit 20.

The sliding pins 21 allow the supporting unit 19 to travel inside the treatment tank 7 based on the level of the mixture to be purified 5, so that the supply element 9 is always positioned below the free surface 4, even when the level of the mixture to be purified 5 in the treatment tank 7 rises or drops.

In addition, the supporting unit 19 comprises constraining elements 23 to the positioning unit 20 which are adapted to prevent the horizontal movement of the supporting unit 19.

The presence of the sliding pins 21 and of the constraining elements 23 allows the movement of the supporting unit 19 along a sliding plane, defined by the vertical sliding guides 22, for the entire depth of the treatment tank 7 and avoids any undesired horizontal movements thereof caused by turbulence in the mixture to be purified 5.

The supporting unit 19 is also provided with a coupling element 24 to allow the initial placement thereof in the treatment tank 7 and the final removal at the end of the treatment.

The operation of the present device 1 is as follows.

Initially, the positioning unit 20 is inserted and fastened inside the treatment tank 7 so as to be at least partially immersed in the mixture to be purified 5.

The supporting unit 19, supporting the shredding pump 2 and the floating means 12, is then positioned inside the treatment tank 7, by means of the coupling element 24, by inserting the sliding pins 21 inside the respective vertical sliding guides 22 of the positioning unit 20.

Once the shredding pump 2 has been immersed in the mixture to be purified 5, the upper portion 17 of the supply element 9 is suitably positioned with the entry port 10 below the free surface 4.

For this purpose, the quantities of gas and liquid introduced into the floating elements 13 are regulated through the ducts 14 and 15, based on the density of the mixture to be purified 5 itself.

Once the treatment has started, the shredding pump 2 sucks the mixture to be purified 5 through the supply element 9 and shreds the solid residues 3 floating on the free surface 4.

During treatment, the treated mixture to be purified 5 flows out of the shredding pump 2 through the outlet connection 8.

In this phase, the level of the mixture to be purified 5 inside the treatment tank 7 lowers and the supporting unit 19 travels downwards, following the vertical sliding guides 22 and keeping inside the vertical sliding plane thanks to the constraining elements 23 which avoid the horizontal movements thereof.

Once the treatment has finished, the supporting unit 19 can be removed from the treatment tank 7 through the coupling element 24.

It has in practice been ascertained that the described invention achieves the intended objects and in particular it is underlined that the device 1 allows effectively removing the solid residues 3 floating on the free surface 4 of the mixture to be purified 5.

In fact, the device 1 allows a correct and constant positioning of the supply element 9 below the free surface of the mixture to be purified 5 and therefore allows an adequate conveying of the solid residues 3 to the shredding pump 2.