FIELD OF THE INVENTION The present invention relates to an apparatus and method for recycling water from slurry sucked by drainage pipes, wells and the like, of a movable installation, in particular adapted to be installed on service vehicles for cleaning and restoring the functionality of the wells of drainage pipes and the like. A vehicle equipped with such an apparatus is also part of the present invention. PRIOR ART

A movable equipment installed on vehicles is commonly used to clean wells and drainage pipes.

Such an equipment usually comprises one or more cisterns, when convenient, high-pressure pumps, slurry suction pumps or compressors; indeed, slurry suction generally occurs by creating a depression in a cistern or compartment thereof, so that the slurry is directly sucked through a specific piping, even if other methodologies are possible.

The cisterns mainly have two objects: providing a water reserve useful for washing the wells or pipes, generally by means of high-pressure pumps, and collecting the sucked slurry.

To increase the efficiency of the operations, and therefore the operating autonomy of the vehicle, an attempt is made to reuse part of the water accompanying the sucked slurry. For example, water may be extracted from a certain level of a cistern or compartment, so as to permit a certain settling of the slurry at the bottom and therefore a minimum separation.

If several compartments or cisterns are present, coarse filtration may be carried out.

For example, slurry may be sucked from a compartment by means of a recycling pump by making it go through a coarse filter. The recovered water may be sent to a specific compartment ready for use. It may then go through other filtration systems or through a cyclone, from which the purified water is collected as seen above, and the thickened portion is sent back to the origin compartment. This increases the quantity of available water and enhances the quality thereof. With the methods and equipment according to the known art, however, the operating autonomy of a vehicle used for the above services is generally still rather limited to a small number of cleaning cycles. Later, there is a need for the vehicle to return to the operating headquarters to drain the collected slurry and fill up with new clean washing water. It would therefore be desirable to increase the operating autonomy of the vehicle, without however further increasing the already significant volume of the on-board cisterns, or the number of compartments. Moreover, it would be desirable to enhance the quality of the available washing water throughout a series of cleaning operations. This to increase the life and reduce the maintenance of the on-board pumps, in particular the high-pressure pumps used for washing.

Furthermore, the legal requirements of the quality of water used for some operations are expected to tighten in many countries. In the case of wells, for example, after cleaning there is a need to fill the siphon with water so as to create a hydraulic guard which prevents any pollutants spilled on the roadway from reaching the drains and which, in any event, isolates the latter from the outside. It is understood that the quality of this water is important to prevent drawbacks such as bad odours, and to delay the need for new draining operations. Moreover, increased water recovery would diminish the volume of the slurry to be disposed of, the number of cleaning operations performed being equal. SUMMARY

The set forth problems have now been solved by means of a movable apparatus, in particular for a vehicle, for cleaning wells of drainage pipes and the like, comprising a slurry collecting tank divided into two parts by a movable bulkhead; said slurry collecting tank may contain, for example, the thickened slurry in the rear part, and in the front part, the dirty water from the rear compartment intented for the slurry, which arrives thereto due to overflowing and/or decanting; a dirty water suction/pumping line which, by means of a coarse separator/filter or other pre-filtration system, connects the dirty water compartment of the slurry tank to a distribution pump of the water to be treated; one or several decanting compartments, and a system for introducing the flocculating element into the dirty water distribution line and/or into the decanting compartments and/or into the slurry tank.

Also within the scope of the present invention is a vehicle equipped with such an apparatus as well as the method for recycling the water from the slurry sucked from drainage pipes, wells and the like.

According to an aspect of the invention, the purified water is collected in a tank for purified water, for successive use, while the thickened part is stocked in the slurry collecting tank.

Unless otherwise specified, tank means a cistern or a compartment thereof or the like, being part of a movable installation for cleaning drainage pipes, wells or the like.

The contents of the appended claims are the particular object of the invention.

LIST OF THE DRAWINGS

The present invention will now be disclosed by means of a detailed description of a preferred, but not exclusive, embodiment shown by way of non-limiting example with the aid of accompanying figure 1 which diagrammatically depicts an apparatus according to the present invention.

DETAILED DESCRIPTION OF AN EMBODIMENT

With particular reference to figure 1 , the apparatus for recycling water according to the present invention comprises a cistern divided into compartments or tanks therein.

In particular, a slurry collecting tank is present, which is divided into two parts or compartments by a movable bulkhead. The slurry collecting tank may contain, for example, the thickened slurry in the rear part, and in the front part, the dirty water from the rear compartment intended for the slurry which arrives thereto due to overflowing and/or decanting.

According to the preferred embodiment shown by way of example in the diagram in Figure 1 , said slurry collecting tank has a first compartment 24 which forms the true slurry collecting tank in which the slurry and/or the material sucked from the well or from the drainage pipe is collected by means of the suction pipe 27. As known, a vacuum is created inside the slurry collecting compartment 24, i.e. a condition of negative gauge pressure so that when the valve 13 is opened, the slurry is sucked by means of the suction pipe 27.

The slurry collecting compartment 24 is separated from an adjacent compartment

23 which forms a decanting or pre-deposit tank in which the particulate material may settle. Again in greater detail, the separation of compartment 24 from the decanting compartment 23 is accomplished by means of a movable bulkhead 25 preferably having a structure as a substantially flat partition in profile, adapted to match with the profile of the internal cross section of the cistern, said partition being hinged about a substantially horizontal, transversal axis, diagrammatically indicated by A, so as to be inclined with respect to the substantially vertical position seen in Figure 1.

During the operation of the apparatus said bulkhead 25 is substantially kept in the vertical position seen in Figure 1 , while it may be inclined by rotating about axis A to facilitate the emptying and washing operations of the slurry collecting tank 24. Therefore, during the operation of the apparatus, the bulkhead 25 serves the function consisting of separating the slurry in the compartment 24 from the liquids contained in the quiet phase, however it also serves the function of pre-filtering because a passage port is conveniently provided at the upper part and at the lower part of said bulkhead. In particular, while the passage port is minimum at the lower part of the bulkhead and substantially corresponds to the clearance required to allow its tipping, the profile of the bulkhead in the upper portion may conveniently have a bevel adapted to facilitate the passage of liquids from the tank

24 to the decanting tank 23. Indeed, the solid phase of the material collected in the slurry collecting tank 24 tends to deposit at the bottom of the cistern, while the obviously lighter liquid phase may overflow the bulkhead 25 by passing in the decanting compartment 23, as diagrammatically shown by arrow F in Figure 1 , said bulkhead thus providing a kind of "too-full" for the tank 24 to be filled. Advantageously, said bulkhead is further equipped with auxiliary filtration means. For example, these filtration means (not shown in the diagram in Figure 1 ) may comprise a plurality of brushes or combs conveniently arranged so as to intercept the flow F which overflows the bulkhead 25 so as to further filter the particulate which is held by preventing the passage thereof into the decanting compartment or tank 23 where the processing water is advantageously stationed over an average time of about 15 minutes.

Turbid water is found in the tank 23 due to the bulkhead 25, from which however, a consistent part of the solid material has already been filtered, consisted of the initial slurry extracted from the well or from the drainage pipe on which the intervention was made to perform the draining.

A line b for introducing flocculating material is provided to further promote the slurry deposition at the bottom of compartment 24. Again with reference to Figure 1 , line b for introducing the flocculating material into tank 24 may advantageously comprise a gate valve 10 to control the flow of flocculating mixture entering the tank 24. As known, the flocculating substance should be mixed in water to be effectively distributed through a pipe to a tank.

Moreover, the cistern comprises at least two other compartments, separated by said slurry collecting tank. Said compartments consist of a clean water tank 21 and a recycled water tank 22. The clean water tank 21 and the processing water tank are connected to eache other by a pipe diagrammatically shown by letter c and equipped with a convenient non-return valve (not shown in the figure) which allows the water to exclusively pass from tank 22 towards tank 21 , while preventing the reverse flow. Therefore, the apparatus according to the present invention is further equipped with means for mixing and distributing the flocculating element within the system. Said means for mixing the flocculating element may particularly comprise a flocculating tank 18 containing the flocculating substance, a pump 3 capable of bringing the flocculating material through a pipe f from the flocculating tank 18 to a tank 19 of mixing the flocculating element. The flocculating substance is mixed within the tank 19 of mixing the flocculating element by means of a mixing pump 2, with the water from the mixing line e connected to the recycling line a departing from the decanting tank 23.

Mixing line e will be conveniently provided with an on-off valve 17. The distribution means of the flocculating element will further comprise a volumetric pump 1 adapted to selectively suck the flocculating mixture from the mixing tank 19 to introduce it into the recycling line a, or when the on-off valve 10 is opened, to introduce it through the pipe b into the slurry collecting tank 24. The apparatus according to the present invention further includes means 26 for filtering the recycled water inside or communicating with said decanting tank 23. Said filtration means 26 may advantageously comprise a mechanical sieve filter, e.g. a Grobfilter of about 700μ or the like is preferred, and are conveniently placed upstream of the water recycling line indicated by a in Figure 1.

A volumetric pump 4 on the recycling line a allows the water to be extracted from the tank 23 towards the recycling line a, through the filtration means 26. A branch of line e is provided downstream of said volumetric pump to send the recycled water to the mixing means of the flocculating element, as described above. The water recycling line a thus allows the extraction of the water from the decanting tank 23, after convenient filtering. Therefore, the water extracted from the tank 23 by pump 4 has already undergone a significant treatment: firstly, the most consistent solid part of the slurry has precipitated into the slurry collecting tank 24 with the aid of the flocculating element introduced by means of pipe b, then a second coarse filtration is performed by means of the auxiliary filtration means of the bulkhead 25, and finally, a more accurate filtration of the dirty water is performed by means of the filtration means 26 before it is introduced into the recycling line. By virtue of this disclosure, it is therefore understood how the recycled water departing from the decanting tank 23 through the recycling pipe a already has a contained degree of turbidity. Nevertheless, the apparatus according to the present invention further includes means for measuring the turbidity of the recycled water 7 on said recycling line a. Said means for measuring the may particularly comprise a sensor 7 to detect the turbidity degree of water, e.g. said sensor may be an analog laser sensor, preferably equipped with a transmitter- receiver system to transmit the turbidity reading data to a specific control unit of the apparatus.

The water recycling line a allows to selectively reintroduce the recycled water into said slurry collecting tank 24, by means of the on-off valve 15, or through the valve 16 in said recycling chamber 22, which as said above is hermetically separated from the adjacent decanting compartment 23 by means of a fixed bulkhead. As will be seen below by describing the operation of the system according to the present invention, the water recycling may be directly commanded by the central control unit of the system which determines the opening and closing of the valves 15 and 16 according to the data received from the sensor 7 and, preferably, to other sensitive data detected by other possible sensors in the system. Therefore the recycled water is collected in said quiet chamber 22 having a turbidity degree below a given threshold value determined each time by the operator or pre-determined as data stored in the CPU central control unit of the control system with which the apparatus according to the present invention is equipped. The recycled water will advantageously remain in said recycling chamber 22 for a time sufficient to ensure further solid substance still in the water is deposited at the bottom of the tank. The optimal time obviously depends on various factors, including the turbidity degree of water, the volume of liquid accumulated and so on, however an average useful time may be estimated of about 25 minutes. As said above, the system provides indeed the mixture of flocculating substance and water being introduced into the recycling line through pump 1. A quantity of flocculating mixture may be advantageously inserted into the recycled water in order to facilitate the particulate precipitation in the recycling tank 22 of the recycled water, should the turbidity level of the recycled water measured by sensor 7 still be high but however below a threshold value deemed acceptable and advising it be directed to the recycling tank 22 rather than to the slurry accumulation tank 24.

As said above, the processing water may be advantageously allowed to decant in tank 22 over a period of about 25 minutes to allow the particulate to be deposited at the bottom of the tank. A drain valve 9 conveniently provided at the bottom of said recycling tank 22 may be opened, if removing the particulate which precipitated at the bottom of the tank 22 during operation is deemed convenient, so as to remove the solid substances by re-conveying them to the slurry accumulation tank 24 through line d. As said above, a further clean water tank 21 is provided in communication with said recycling tank 22. Water may pass from the recycling tank 22 to the clean water tank 21 by means of a piping line c, on which a non return valve (not shown in the diagram in Figure 1 ) may be advantageously provided, and a second turbidity detection sensor diagrammatically indicated in the figure by reference number 6.

The water passes from the recycle tank 22 to the tank 21 through the line c while sensor 6 detects the turbidity level of the water.

If the turbidity value detected is above a threshold value, whereby the water is not deemed usable for the washing operations for which it is recycled, the system allows to insert further flocculating element into the tank 22 by means of pipe a and valve 16, for example. In any event, the water may be further allowed to decant both in the clean water tank 21 and in the recycling tank 22, whether or not the decision is made to introduce further flocculating element when a too high turbidity value is detected. As said above, in the case of tank 22, the solid particulate deposited at the bottom due to the effect of gravity may be removed through valve 9 and line d, while it may be removed from tank 21 by means of a valve 8 specifically provided at the bottom of tank 21 and suitable for draining the particulate towards the slurry accumulation tank 24 always through line d.

Moreover, the system or apparatus according to the present invention may advantageously comprise a line g for extracting water, by means of pump 5, from tank 21 and directing it to a sample taking tank 20. The presence of tank 20 allows the operator to check the purity degree of the clean water contained in tank 21. Thereby, the verification of the quality of the water filling the clean water tank 21 may be carried out at every slurry collecting cycle, and it is important because, as said above, the clean water of tank 21 may be employed, through line 27 and valve 14, to wash and/or drain the well or the drainage pipe on which the intervention is being made, and therefore this water is required to comply with specific parameters related to the presence of pollutants.

The operation of the water recycling apparatus according to the present invention is as follows. The slurry will be sucked from the well or from the drainage pipe to be drained by means of the suction pipe 27, which may be shaped according to a trunk arm of known type, for example. The sucked slurry is conveyed to the slurry accumulation tank 24 by means of valve 12.

Flocculating element may be advantageously introduced into the slurry accumulation tank 24 by means of the pipe b and the on-off valve 10.

The apparatus according to the present invention includes means for mixing the flocculating substance. The flocculating substance stocked in a tank 18 is taken by means of a pump 3 placed along pipe f and mixed, by means of the mixing pump

2, in the mixing tank 19 with water from the recycling line a, preferably taken upstream of said turbidity sensor 7.

As the tank 24 is filled, the solid part settles at the bottom also due to the action of the flocculating element, and part of the slurry (the most liquid part having a lower density) overflows the bulkhead 25 while being further coarsely filtered by the filtration means having a brush or comb at the bulkhead, and then passing to the decanting tank 23.

At this point the water is extracted from the decanting tank 23 through the water recycling line a by means of the volumetric pump 4.

The turbidity sensor 7 is placed along the water recycling line a, preferably downstream of said pump 4.

The system may operate according to various functionalities, according to the water turbidity data measured by sensor 7, which data are read by the CPU central control unit.

For example, if the turbidity value measured by sensor 7 is still very high, the water may be recycled again at the slurry collecting tank 24 through the line a and the on-off valve 13.

If the turbidity value of sensor 7 is lower than a certain threshold value, the recycled water may be directly conveyed to the recycling tank 22 by means of the on-off valve 16.

According to the turbidity value detected by sensor 7, the system allows to operate in an extremely versatile manner in terms of managing the water recycling. For example, if an intermediate turbidity value is detected among the preceding ones, introducing the recycled water into the recycling tank 22 may be chosen, while introducing the mixture of flocculating element into the water through pump 1 and pipe b, connected to the water recycling line a, as shown in the diagram. Again, for particularly high turbidity values, water may instead be recycled at the slurry collecting tank 24 through the on-off valve 15 with the introduction of further flocculating element directly into the tank 24 by means of pipe b and valve 10. The system control based on the turbidity data detected by sensor 6, which detects the turbidity value of the water entering the clean water tank 21 from the recycling tank 22 through pipe c, is also highly versatile. The data detected by sensor 6 may also be advantageously read by the central control unit of the system or directly by the operator, thus allowing through an automatic function or a choice by the operator to control the opening of the outlet valves 8 and 9 to empty the tanks and/or determine the introduction of new flocculating element into the tank 22, or again to inhibit the water drainage by preventing the valve 14 placed on the line 27 from opening, which valve intercepts the fluid.

According to the turbidity value detected by sensor 6, the recycling time may be determined, for example, for further decantation in the tanks 21 and 22, which time may also be according to the turbidity measured by the sensor 7, for example, to the possible quantity of flocculating element introduced through pump 1 into the recycling line, and to other parameters which may be conveniently set by the operator when programming the central control unit of the system or manually set by means of a convenient control panel. Opening the drain valves 8 and 9 may also be decided according to the measured turbidities and therefore may be directly controlled from the central control unit. It has thus been shown how the apparatus for cleaning wells of drainage pipes and the like according to the present invention achieves the object and the purposes proposed. In particular, it has been disclosed how the apparatus according to the present invention is capable of enhancing the quality of the washing water available for the cleaning operations, while increasing the average life and reducing the maintenance of the on-board pumps, in particular those at high pressure used for washing. Moreover, the apparatus according to the present invention allows to increase the operating autonomy of the service vehicle equipped with said apparatus, thus allowing several cleaning cycles to be operated as it is capable of recycling a greater quantity of water.

Not last object achieved by the apparatus according to the present invention is that of allowing the quantity of flocculating element introduced into the system to be controlled, as well as the water recycling modes according to the turbidity value detected by one or more sensors.

It has been ascertained how the apparatus according to the present invention allows to obtain sufficiently high volumes of highly clean water with defined cycles (about every 20 min.). Thereby, after each operation of cleaning the well, the functionality thereof may be immediately restored by filling it with clean water again. This permits high hygienic standards to be kept, for example by preventing odours or even avoiding or reducing the presence of typical insects of stagnating waters.

Several modifications may be made by a person skilled in the art without departing from the scope of protection of the present invention. Hence, the scope of protection of the claims should not be limited by the disclosures or by the preferred embodiments shown in the description by way of example, but rather the claims should comprise all features of patentable novelty inferable from the present invention, including all features which would be treated as equivalent by a person skilled in the art.