EP0937510B1

EP0937510B1 - Method and device for washing rubbish bins on a vehicle

Info

Publication number: EP0937510B1
Application number: EP19980830080
Authority: EP
Inventors: Ermanno Pilenghi
Original assignee: Aep Di Pilenghi E & C Srl
Current assignee: Aep Di Pilenghi E & C Srl
Priority date: 1998-02-19
Filing date: 1998-02-19
Publication date: 2000-05-24
Anticipated expiration: 2018-02-19
Also published as: GR3033804T3; DE69800160T2; DE69800160D1; ES2149635T3; EP0937510A1

Description

The present invention relates to a method for washing trash and garbage containers on a vehicle, comprising the phases exposed in the preamble to claim 1. Also subject of the invention is a device for washing trash and garbage receptacles mounted on a vehicle, comprising the characteristics expressed in the preamble to claim 12. The invention finds particular use in the sector of public services, to wash the receptacles serving to contain trash and garbage.

As is well known, periodic washing operations of the receptacles used for trash and garbage collection is normally performed by means of suitable washing devices mounted on vehicles.

Washing devices of this sort generally comprise a first tank of considerable size, filled with clean water, possibly with additives mixed therein, connected to a washing station by means of the pipelines of a usual hydraulic circuit. The washing station comprises a washing chamber set to receive the containers to be washed and a series of dispensing nozzles distributed within the washing chamber itself. The container introduced into the washing chamber is subjected to one or more jets of water exiting the dispensing nozzles under high pressure.

The washing station is in turn connected, also hydraulically, to a second empty tank, identical to the first one both in shape and size, set to contain the waste water resulting from the washing operations.

Once the receptacle has been washed, it is returned to the collection station and the remaining turbid water obtained from the wash is injected into the second tank. At the end of the work shift, entailing the performance of a certain number of washing cycles, the first tank is empty and the second tank is full of turbid water.

This type of device for washing trash and garbage containers presents a first problem linked closely to the transport of large masses of water of considerable weight. This makes it necessary to use a vehicle so structured and dimensioned as easily to withstand the stresses deriving from the presence of such loads.

It is necessary to keep in mind that the transport of large masses of water also limits freedom of design, since one must account for the centres of gravity of such masses and of the means of transport, both under static conditions and in motion. In many cases, in order to distribute the water masses in a sufficiently balanced manner, it is necessary to provide for more than two tanks, with consequent increases in the cost of the entire device.

Another problem is given by the fact that the tanks currently in use are subject to corrosion phenomena stemming from containment of aggressive waters. In spite of the use of stainless steel for their construction, steel is attacked and corroded by all those waters that present a rather high level of acidity and/or salinity. To solve this problem, plastic or aluminium tanks could be produced, better able to contrast corrosion. This however is not possible, since manufacturing aluminium or plastic tanks of large size as are those currently in use would be economically disadvantageous.

It should also be considered that, at the end of the work shift, the turbid water accumulated must be discharged as waste into rubbish tips. The cost of discharging waste into such tips is proportional to the volume of waste to be discharged. Hence, it is easy to see that discharge costs have considerable impact on total expenses.

In the attempt to solve the problems listed above, washing devices operating with water recirculation have been proposed. In such devices water is recovered during the washing operation and is purified by means of decantation and/or filtration to be re-used for subsequent washing operations.

Examples of such devices are described in patent documents FR 2714897, EP 153455 and US 3291144. Existing water recirculation devices, however, are ineffective, since they are not able to purify water in a sufficiently accurate way to guarantee hygiene in subsequent washings. The applicant has noted that, due to the nature and size of the particles suspended in the residual water from trash and garbage container washings, an effective filtration would require the use of filters of considerable size and prohibitive cost. On the other hand, the separation of the suspended particles by means of simple decantation is currently impossible to obtain in a satisfactory manner on a moving vehicle, due to the inevitable jolts and subsequent mixing undergone by the water during decantation.

The abstract of Japanese patent JP-A-2157004 achieves a protection of a settling tank against shocks due to outside vibrations, by providing a stabilizing frame connected to the upper part of the settling tank by a shock-absorbing mechanism. The stabilizing frame comprises a plurality of plates vertically extending within the tank, so as to divide this latter into rectangular parrallelepiped chambers. However, also such a construction is not suitable for decantation during the vehicle travelling.

The object of the present invention is substantially to solve the problems present in the prior art, proposing a washing method and device which, whilst presenting a very simple structure with low manufacturing cost, allow excellent purification of the recycled water even while the vehicle travels.

This object and others beside, which will become more readily apparent in the course of the present description, are substantially attained by a method for washing trash and garbage containers on a vehicle, characterised in that it comprises the characteristics exposed in the characterising part of claim 1.

According to the present invention, a device is also proposed for washing trash and garbage containers mounted on a vehicle, characterised in that it comprises the features expressed in the characterising part of claim 12.

Additional characteristics and advantages shall be made more evident in the detailed description of a preferred, but not exclusive, embodiment of a method for washing trash and garbage containers on a vehicle, and of a device for washing trash and garbage containers operating according to the aforementioned method, in accordance with the present invention.

Such description shall be made hereafter with reference to the accompanying drawing, provided purely by way of non-limiting indication, whose sole figure schematically shows a device according to the present invention.

With reference to such Figure, the number 1 indicates in its entirety a device mounted on a vehicle for washing trash and garbage containers.

In a way known in itself, the device 1 comprises at least a washing station 2 engaged on the chassis of a vehicle, not shown because it is not relevant for the purposes of the invention. To the washing station 2 is connected a hydraulic circuit 3 fed by at least one tank 4 set to contain water whereto may be added surface-active compounds or other suitable additives. More in particular, from the tank 4 extends a delivery pipeline 5 connected to dispensing means 6 positioned in the washing station 2.

The tank 41 having indicatively a total capacity of 800-1000 litres, can be filled for instance with 600 litres of water, or in any case with a quantity of water indicatively corresponding to that dispensed to wash at least thirty trash or garbage containers.

The dispensing means 6 comprise a series of dispensing nozzles 7 distributed on the inner walls and oriented towards the centre of a washing chamber 2a comprised in the washing station 2. The washing chamber 2a is suited to receive at least one trash or garbage container, indicated by the dashed line with the number 8, to be subjected to the washing treatment. In a way known in the art, the container 8 is picked up and positioned in the washing chamber 2a by suitable gripping means set on the vehicle which, when washing is complete, also disengage the container itself from the washing station to reposition it on the ground.

A first pump 9, operatively associated to the delivery pipeline 5 of the hydraulic circuit 3, intakes the water from the tank 4 conveying it to the dispensing nozzles 7. To the washing station 2 are also associated collecting means 10 to collect the water used to wash the container 8.

In the example shown, such collecting means 10 comprise one or more collecting sumps 11 present on a base wall 12 of the washing chamber 2a, wherein the turbid water obtained from washing the containers 8 is deposited.

On each collecting sump 11 can be applied a filtration grid 11a able to retain any solid waste which may come out of the container 8 when it is washed, thereby preventing the respective sump 11 from becoming clogged. The collecting means 10 further comprise a second pump 13 associated to a first return pipeline 14 extending from the collecting sumps 11. The second pump 13 intakes the turbid water deposited in the collecting sumps 11 and sends it into the first return pipeline 14, whereon can be advantageously installed an interchangeable filter 15 which retains the remaining solid bodies that passed through the grids 12 of the collecting sumps 11.

The device 1 further comprises at least one purifying unit 16 operatively interposed between the collecting means 10 and the tank 4, to purify the turbid water coming from the collecting means themselves, as well as recirculation means 17 to send into the tank 4 the water purified by the purification unit 16.

The purification unit 16 essentially comprises at least one settling station 18, as well as a mixing station 19 operatively interposed between the collecting means 10 and the settling station 18 to add and mix flocculating substances in the water coming from the collecting means. The mixing station 19 essentially comprises at least a first and a

second container

20, 21, having each a capacity corresponding essentially to one fourth of the quantity of water provided in the tank 4. To each

mixing container

20, 21 is associated at least a

dosing meter

22, 23 to inject at least one flocculating substance into the turbid water conveyed into the

respective container

20, 21. Inside each

container

20, 21 further operates a mixing organ 24, 25 designed to maintain the turbid water agitated in order to guarantee a homogeneous dispersion of the flocculating substance injected by the

respective dosing meter

22, 23.

To the

mixing containers

20, 21 are further associated selecting means 26, to alternate mixing between the first and the second container. More in particular, the selection means 26 operate in such a way that the mixing phase is performed in the second mixing container 21 while the first mixing container 20 is being emptied and subsequently filled, and vice versa.

To this purpose, the selection means 26 respectively comprise for the first and the

second container

20, 21 an

inlet valve

27, 28, an outlet valve 29, 30 and a

level sensor

31, 32.

When the second pump 13 intakes the turbid water from the collecting sumps 11 to send it to the mixing unit 19, the inlet valve 27 of the first container 20 is in an open condition, whereas the

remaining valves

28, 29 and 30 are in a closed condition. The turbid water is thus deposited into the first container 20. When the water placed in the first container 20 reaches a pre-set level of maximum filling, the level indicator 31 emits a signal as a result whereof the inlet valve 27 of the first container 20 is commanded shut, and the inlet valve 28 of the second container 21 is commanded open, thereby sending thereto the water coming from the second pump 13. While the second container 21 is being filled, in the first container 20 the flocculating substances previously introduced upon the action of the respective dosing meter 22 are completely mixed.

Upon completion of the mixing phase, the outlet valve 29 of the first container 20 is commanded open to allow the first container to be emptied.

At the moment wherein the turbid water reaches the pre-set level of maximum filling in the second container 21, the intervention of the level indicator 32 shall determine, for the second container itself, the execution of the same mixing and emptying cycle already described for the first container 20.

The emptying of the first and of the

second mixing container

20, 21 is preferably managed by a recirculation pump 33 comprised among the recirculation means 17. The recirculation pump 33, started simultaneously with the opening of the outlet valves 29, 30, thrusts the water through the settling station 18 to inject it into a main recirculation pipeline connected to the tank 4.

In the settling station 18 a decantation phase is performed, whereupon the impurities present in the water are separated from the water itself, precipitating in the form of sludge.

In accordance with the present invention, the settling station 18 is provided with means to inhibit the water from mixing when the vehicle travels. The decantation phase can therefore advantageously be effected at least partially also after disengagement of the container 8 from the washing station 2 and resumption of travel by the vehicle to reach the next container to be washed. The aforesaid means to inhibit mixing essentially provide for the settling station 18 to comprise at least one hermetically sealed decantation container 35 presenting at its top at least one intake inlet 36 communicating with the collecting means 11, with interposition of the mixing station 19, and at least one discharge outlet 37 that communicates with the tank 4 through the recirculation pipeline 34. The decantation container 35 preferably presents capacity essentially ranging between ½ and 2/₃ of the quantity of water placed in the tank 4. With the aid of the recirculation pump 33, preferably installed upstream of the decantation container 35, the settling container itself is kept essentially full of water during the entire settling phase, preventing the accelerations and jolts inevitably brought about while the vehicle travels from causing the water to mix, thereby hampering proper decantation. The liquid inserted into the settling container 35 separates through density difference in two distinct parts: all the impurities linked to the flocculating substances settle in the form of sludge to the bottom of the container 35, whereas clarified water remains in the upper part of the container.

Moreover, the means to inhibit mixing preferably comprise at least a partition baffle 38 which subdivides the inner space of the decantation container 35 into an inlet chamber 39 communicating with the intake inlet 36, an outlet chamber 40 connected to the discharge outlet 37, and a conveying vat 41, placed at the base of the container itself, which places the inlet chamber 39 in communication with the outlet chamber 40.

The conveying vat 41 presents walls converging downward, in the direction of an accumulation sump 42 positioned below the conveying vat itself.

The decanted sludge is thus collected in the conveying vat 41 and thereby conveyed into the accumulation sump 42.

According to the invention, the sludge is periodically extracted from the accumulation collector 42 to be transferred into a collecting tank 43. For this purpose, in the example shown a pump 44 or equivalent transfer means are provided, operating on a connecting pipeline extending between the bottom of the accumulation sump 42 and the collecting tank 43. The transfer pump 44 is started and shut off selectively upon command from sensor means 46 when the sludge in the sump 42 reaches respectively a maximum threshold level and a minimum threshold level.

The sensor means 46 can advantageously comprise at least a first photo-electric sensor 47 operating through at least one transparent portion 48 of the sump 42 in correspondence with the maximum threshold level, to command the transfer pump 44 to start operating when the sludge intercepts a light beam emitted by the first sensor itself. The transparent portion 48 is further operated on by at least a second photo-electric sensor 49 positioned in correspondence with the minimum threshold level, to command the transfer pump 44 to shut down when the sludge frees the light beam emitted by the second sensor itself.

The clarified water present in the outlet chamber 40 is thrust into the recirculation pipeline 34 through the discharge outlet 37 simultaneously with the injection of new liquid by the recirculation pump 33, during a new emptying phase of one of the mixing

containers

20, 21. In proximity with the discharge outlet 37 can also be mounted an auxiliary filter 50 able to retain any particles which may still be present in the water.

The clarified water is then sent into the tank 4 to be used again in subsequent washing phases.

In accordance with an additional feature of the present invention, immediately upstream of the tank 4, and in any case in a section of the recirculation pipeline 34 lying between the tank itself and the settling station 18, is operatively positioned a unit 51 for the elimination of bacteria, essentially comprising at least a UVC lamp placed in a shielding case and set up to irradiate the water flowing towards the tank itself thereby completely neutralising the bacterial charge present in the water itself.

The sludge collection tank 43 can advantageously present a sufficient capacity to allow the accumulation of the sludge produced during at least one full work shift.

Additionally or alternatively, the sludge extracted from the decantation container 35 may be subjected to a dehydration and compaction phase through the removal of the water present therein. For this purpose, the collecting tank 43 can periodically be emptied when the sludge therein reaches a pre-set maximum level of filling. Under the action of a high pressure pump 52, the sludge drawn from the collecting tank 43 is sent along a delivery pipeline 53 connected to a filtration unit 54 set to perform the aforesaid dehydration phase.

Such filtration unit 54 can advantageously comprise a filter press, not described in detail herein since it is known and conventional in itself. The water extracted from the sludge in the filter press 54 is conveyed into a collecting sump 55 communicating with the recirculation pipeline 34 upstream of the bacteria-eliminating unit 51, thereby being sent back into tank 4 after neutralisation of the bacterial charge present therein.

The present invention fully attains the proposed objects. The means adopted in the subject device, and particularly in the settling station associated thereto, enable to effect decantation in an extremely effective manner, obtaining excellent clarification of the washing water in spite of the fact that the decantation takes place on a moving vehicle.

Through the use of a settling station constructed in accordance with the invention, it has been possible considerably to reduce, with respect to the prior art, the size of the tank and consequently the volumes of the masses of water in motion. The reduction in the size of the tank allows to use tanks made of materials such as plastic or aluminium which better contrast the corrosive effect of any aggressive waters present. It should be considered that, with the reduction in the size of the tank and hence in the masses of water, the means of transportation used for the installation of such devices can present dimensions and weights advantageously reduced compared to the state of the art.

A greater freedom of design is also attained for the devices to be installed on the vehicles, as it is no longer necessary to take into account the baricentre shifts entailed by the displacement of large masses of water.

Lastly, but no less importantly, through the aid of a filter press the waste substances are compacted into waste blocks having greatly reduced volume with respect to the volume of the turbid water discharged by prior-art devices, presenting a considerable decrease in disposal costs. It should be noted that such compaction can also be performed by means of a filter press installed on the ground instead of on the vehicle carrying the washing device.

At the end of the work shift, the residual water can advantageously be discharged into the usual sewer lines, without requiring discharge in a tip with the costs deriving therefrom.

Claims

Method for washing trash and garbage containers on a vehicle comprising the phases of:

positioning a trash and garbage container (8) in at least one washing station (2);

feeding with water contained in at least one tank (4) dispensing means (6) set in the washing station (2) to wash said trash and garbage container (8);

collecting the dispensed water with collecting means (10);

purifying the water thus collected;

sending the purified water to the tank (4);

disengaging the trash and garbage container (8) from the washing station (2);

characterised in that the purification of the water comprises at least one decantation phase effected at least partially while the vehicle travels after disengagement of the trash and garbage container (8) from the washing station (2), in at least one settling station (18) provided with containment means to prevent the water from mixing in the settling station.
Method according to claim 1, wherein settling is performed in at least one hermetically sealed decantation container (35) kept essentially full of water.
Method according to claim 1, wherein during said decantation phase the following phases are accomplished:

conveying decanted sludge into an accumulation sump (42) positioned at the bottom of said settling station (18);

extracting the sludge from the accumulation sump (42) when the sludge accumulated therein reach a pre-set level;

transferring into a collecting tank (43) the sludge extracted from the accumulation sump (42).
Method according to claim 1, further comprising the phase of mixing with flocculating substances the water coming from the collecting means (10) before the decantation phase.
Method according to claim 4, wherein said mixing phase is performed alternatively between a first and a second mixing container (20, 21) comprised in a mixing unit (19).
Method according to claim 5, wherein said mixing phase is performed in the second mixing container (21) during the emptying and the subsequent filling of the first mixing container (20), and vice versa.
Method according to claim 1, further comprising a dehydration phase of the sludge obtained from said decantation phase.
Method according to claim 7, further comprising the phase of sending into said tank (4) water obtained from said sludge dehydration phase.
Method according to claim 7, wherein said sludge dehydration phase occurs through the use of a filter press (54).
Method according to claim 3, further comprising the following phases:

emptying the collecting tank (43) when the sludge contained therein reaches a pre-set level;

dehydrating the sludge removed from the collecting tank (43).
Method according to claim 1, further comprising at least one phase of eliminating bacteria from the purified water, before sending such water to the tank (4).
Vehicle mounted device for washing trash and garbage containers comprising:

at least one washing station (2) set to engage operatively at least one trash and garbage container (8);

at least one tank (4) containing washing water;

dispensing means (6) connected with said tank (4) and set in the washing station (2) to direct at least one jet of water onto the trash and garbage container (8);

collecting means (10) operating in said washing station (2) to collect the water used to wash the trash and garbage container (8);

at least one purification unit (16) comprising at least one settling station (18) operatively interposed between said collecting means (10) and said tank (4) to purify the water coming from the collecting means (10);

recirculation means (17) to send into the tank (4) the water purified by the purification unit (16);

characterised in that said settling station (18) is provided with containment means to prevent the water in the settling station from mixing when the vehicle travels, said containment means comprising:

at least one hermetically sealed decantation container (35), presenting at least one intake inlet (36) communicating with said collecting means (10) and at least one discharge outlet (37) positioned in the upper part of said container (35) and connected with said tank (4);

at least one recirculation pump (33) communicating with said container (35) to maintain the latter constantly filled with water coming from the collecting means (10).
Device according to claim 12, wherein said decantation container (35) presents internally at least one partition baffle (38) defining an inlet chamber (39) communicating with said intake inlet (36) and an outlet chamber (40) connected to said discharge outlet (37), said inlet (36) and outlet (37) chambers being mutually interconnected by means of a conveying vat (41) positioned at the base of the decantation container (35).
Device according to claim 13, wherein said intake inlet and discharge outlet (36,37) are located in an upper part of said decantation container (35).
Device according to claim 12, wherein said decantation container (35) presents at least one sludge accumulation sump (42) positioned below a conveying vat (41) positioned at the base of the decantation container (35) and presenting walls converging towards the accumulation sump itself.
Device according to claim 15, wherein said settling station (18) further comprises:

at least one sludge collection tank (43);

means (44) for transferring sludge from the accumulation sump (42) to the collecting tank (43);

sensor means (46) to start and stop the transfer means (44) selectively when the sludge in the accumulation sump (42) reaches respectively a maximum and a minimum threshold level.
Device according to claim 16, wherein said sensor means (46) comprise:

at least a first photo-electric sensor (47) operating through at least one transparent portion (48) of said collector (42) in correspondence with said maximum threshold level to command the transfer means (44) to start when the sludge in the accumulation sump (42) intercepts a light beam emitted by the first sensor itself;

at least a second photoelectric sensor (49) operating through said at least one transparent portion (48) in correspondence with said minimum threshold level to command the transfer means (44) to stop when the sludge in the accumulation sump (42) free a light beam emitted by the second sensor itself.
Device according to claim 12, wherein said purification unit (16) further comprises a mixing station (19) operatively interposed between the collecting means (10) and the settling unit (18) to mix flocculating substances in the water coming from the collecting means (10).
Device according to claim 18, wherein said mixing station (19) comprises at least a first and a second mixing containers (20,21) and selection means (26) to alternate mixing between the first and the second container (20,21).
Device according to claim 19, wherein the mixing station (19) comprises, for each container (20,21):

at least one meter (22,23) for the dosage of flocculating substances, engaged to the respective container (20,21);

at least one mixing organ (24,25) operatively engaged within the respective container (20,21).
Device according to claim 12, wherein said purification unit (16) further comprises at least one filtration station (54) to dehydrate sludge decanted in said settling station (18).
Device according to claim 21, wherein said filtration station comprises a filter press (54).
Device according to claim 12, further comprising at least one station (51) for the elimination of bacteria interposed between the purification unit (16) and the tank (4).
Device according to claim 23, wherein said station (51) for the elimination of bacteria comprises at least one UVC lamp.