EP2545840A1

EP2545840A1 - Improved rinsing station for tunnel dishwashers, and a method for controlling such a rinsing station

Info

Publication number: EP2545840A1
Application number: EP12176449A
Authority: EP
Inventors: Luciano Berti; Marco Colombo
Original assignee: Comenda Ali SpA
Current assignee: Ali Group SRL
Priority date: 2011-07-15
Filing date: 2012-07-13
Publication date: 2013-01-16
Anticipated expiration: 2032-07-13
Also published as: ES2471946T3; EP2545840B1; ITMI20111323A1

Abstract

A rinsing station (21) for tunnel (100) dishwashers, said rinsing station (21) comprising rinsing spray nozzles (27) connected to a network for supplying net water (103), a pre-rinsing tank (30) for collecting a pre-rinsing solution connected to pre-rinsing spray nozzles (27'), said pre-rinsing solution comprising the net water (103) used in the rinsing phase of the preceding cycle and the substances removed from the rinsed dishes, so that the pre-rinsing phase of the following cycle takes place through the use of rinsing water used in the preceding cycle, characterised in that it comprises a control unit (102) connected on one side to sensors (101) for measuring the characteristics of said pre-rinsing solution contained in said pre-rinsing tank (30) and on the other side connected to actuator means (104) for controlling the delivery of net water (103) to said spray nozzles (27) during the rinsing phase according to the values measured by said sensors (101).

Description

The present invention refers to an improved rinsing station for tunnel machines and to a method for controlling such a station.
In particular, the present invention refers to a rinsing station that is capable of performing a preliminary pre-rinsing step before the final rinsing of the dishes.
By the term "dishes" we mean plates, cutlery and glasses, as generally understood, but also saucepans, containers, kitchen utensils and other similar objects. Furthermore, for the sake of simplicity, by the term "dishes" we shall also mean the mobile means which support the aforementioned dishes during their forward movement in the dishwasher.
In such a way also such supports shall be effectively washed and rinsed by the multistage rinsing module according to the present invention.
By the term "tunnel" machine we mean all those dishwashers in which the dishes are moved so as to go, in succession, through a plurality of operation steps. Currently, it is the common goal of many manufacturers, as well as the purpose of the present invention, to study new solutions that are capable of reducing the consumption of water used in the final rinsing phase of the dishes.
Indeed, advantageously, by decreasing the amount of water used there is also a corresponding substantial saving in terms of energy used for heating it, as well as a lower consumption of detergents and rinse aid.
A first solution proposed for such a purpose is described for example in patent EP1815779 .
In such a patent it is foreseen for the water that is used for the pre-rinsing to be, at least partially, the same water used in the preceding rinsing cycle.
Indeed in such machines there is a collection tank of the water used for rinsing, or rather heated net water with rinse aid added to it, which is re-used in the preceding pre-rinsing step for removing most of the detergent from the dishes before their final rinsing, by means of "new" net water.
Such a method of re-using water in the pre-rinsing step that was previously used for rinsing allows to significantly reduce the consumption of water from the net and, therefore, also the consumption related to energy, detergent and rinse aid.
In parallel with the efforts aimed at reducing consumption of net water used for rinsing dishes, it is however necessary to safeguard the overall efficiency of the washing cycle.
Patent application WO10144307 indeed describes a tunnel machine of the type described above, or rather a machine that recycles the water previously used for rinsing in the pre-rinsing phase of the following cycle, in which it is further provided for sensors arranged actually inside the tank for collecting such water to be re-used.
In particular, such sensors are connected to a control unit which controls a possible increase of detergent in the washing phase, wherein said increase is a function of some parameters measured in the collection tank.
Prior art document DE102009032964 describes a machine provided with sensors for measuring the characteristics of the pre-rinsing solution that are capable of modifying the delivery of the net water according to the values measured by such sensors.
However, such a solution has the drawback of being insensitive to the variations of the characteristics of the net water.
In other words, in order to correct a particular characteristic of the pre-rinsing solution, a particular delivery of net water is commanded, which however, having in the meantime changed its characteristics, does not bring the pre-rinsing solution to the balance required but rather moves it further away.
Prior art document EP2057929 describes on the other hand, a machine that is provided with sensors for measuring the characteristics of the net water that is capable of modifying the delivery of detergent according to the measured characteristics of the net water.
The purpose of such a document EP2057929 is therefore that of controlling the amount of detergent delivered and not that of reducing the delivery of net water.
It is also clear that if a man skilled in the art, facing the problem of finding alternative solutions to those known, had combined the teachings of the prior documents EP2057929 and DE102009032964 , he would not have come to the solution proposed by the present invention.
Indeed by combining such known documents the man skilled in the art would have conceived a machine with sensors of the characteristics of the pre-rinsing solution capable of modifying the delivery of the net water and with sensors of the net water capable of modifying the amount of delivered detergent without solving the problem of the possible variations of the characteristics of the net water.
There would not therefore be any modification to the delivery of net water when the characteristics thereof vary.
In other words there is no suggestion in the prior art documents EP2057929 , DE102009032964 of cross-referencing the measured values of the pre-rinsing solution and of the net water for reducing the consumption of net water and at the same time reaching the required values in the pre-rinsing tank.
The purpose of the present invention is that of making an improved rinsing station for tunnel machines and a method for controlling such a station that are capable of solving in a different manner with respect to the prior art the problems relative to decreasing the consumption of water in the rinsing station without jeopardising the overall efficiency of the washing cycle.
These purposes according to the present invention are achieved by making an improved rinsing station for tunnel machines and a method for controlling such a station as outlined in claims 1 and 3, respectively. Further characteristics of the invention are highlighted in the dependent claims.
The characteristics and the advantages of an improved rinsing station for tunnel machines and a method for controlling such a station according to the present invention shall become clearer from the following description, given as an example and not for limiting purposes, with reference to the attached schematic drawings, in which:

figure 1 is a diagram of a tunnel dishwasher that is provided with a collection tank of the water used for rinsing and intended to be used in the following cycle during the pre-rinsing phase;
figure 2 is a diagram of the controlling elements according to the present invention associated with the machine of figure 1.

With reference to figure 1, a tunnel dishwasher 100 is shown.
Such a machine 100 comprises at least one washing zone 11 that is provided with means 12, 13 for dispensing a liquid substance, generally water or water mixed with detergents, suitable for being dispensed under pressure on the dishes.
According to the preferred embodiment shown in figure 1 the tunnel machine 100 also comprises a pre-washing station 20 and a rinsing station 21 inside which both the pre-rinsing phase, and the rinsing phase are performed.
During the operation of the machine 100 the dishes to be washed go, in succession, through the pre-washing 20, washing 11 and rinsing 21 stations arranged on special transport means, such as conveyor belts or baskets.
The pre-washing 20 and washing 11 stations have a pre-washing tank 22, a washing tank 23, respectively, to which they are connected by at least one pump 24 and by a pump 14, respectively.
Also the rinsing station 21 is provided with a collection tank 30 of the water delivered by the nozzles 27 during the rinsing phase and intended to be used in the pre-rinsing phase during the following cycle.
For such a purpose it is possible to foresee a pump 31 connected to an upper transversal manifold arm 25 and a lower transversal manifold arm 26, each provided with a plurality of pre-rinsing spray nozzles 27'.
According to a possible solution, the nozzles 27 can coincide with the pre-rinsing nozzles 27', represented in a broken line in figure 2.
In the preceding paragraphs, like in the rest of the description, for the sake of clarity, the word "cycle" is used to indicate all the actions which are carried out in succession on the dishes from when they are introduced to when they come out from the machine. However, it is worth clarifying that it is not an actual cycle but rather a series of operations that are carried out in succession, in different work stations or modules, on moving dishes.
In the representation shown it is possible to foresee at least one further delivery arm 28, 29 that can be activated or deactivated with an adjustment valve 32 as a function of the speed of movement of the dishes.
In order to ensure a correct rinsing phase, the rinsing station 21 comprises at least one boiler 33, or an equivalent means, for warming the water to be delivered during rinsing.
Moreover, it is provided at least one solenoid valve 34, or a pump or equivalent means, for closing or opening the connection with the water network for supplying rinsing water.
As per se known, the re-use of the water used for rinsing during the preceding cycle in the pre-rinsing phase allows to significantly reduce the consumption of rinsing water drawn from the network, and therefore also the consumption of the energy needed in order to heat it, and the amounts of rinse aid needed.
However, as already mentioned, in addition to minimising the consumption of net water it is necessary to safeguard the overall efficiency of the washing cycle.
For such a purpose, according to the present invention, it is foreseen an alternative system of dependent retroactive control from two different measurements, one relative to the pre-rinsing solution and the other relative to the net water.
The first of the aforementioned measurements is obtained through detection sensors 101 of some properties of the solution contained in the tank 30, whereas to carry out the second measurement the system also provides means 105 for controlling the state of the net water in inlet so as to exclude, in such a way, variables due to the change over time of the characteristics of the net water 103.
The results of both of such measurements are delivered to a control unit 102 which, once the data has been processed, controls actuators 104, or equivalent means, for adjusting the flow-rate of water delivered from the network 103 in the final rinsing phase.
Therefore, advantageously, the present invention makes it possible to calibrate with continuity each time the delivery of clean net water for rinsing, avoiding on one hand wastage and always ensuring a correct cleaning efficiency.
On the contrary, according to the prior art for a certain value of the pre-rinsing solution there should be a certain corresponding value for supplying net water independently from the changing of the characteristics of the latter.
On the other hand, according to the present invention, when also controlling such a parameter, a measured value of the pre-rinsing solution does not necessarily correspond to a certain net water delivery value but the latter is calculated each time also as a function of the characteristics of the net water itself.
On one hand, this allows to optimise consumption, indeed it could be necessary for there to be a smaller delivery in particular cases, whilst still having an optimal wash, solving the problem of the oscillations of the characteristics of the net water.
It is very simple to understand how the improved rinsing station for tunnel machines according to the invention operates.
As visible in figure 2, the control unit 102 is connected to the sensors 101 and to the means 105 for controlling the state of the net water, which respectively foresee a measuring of some characteristics of the solution present in the tank 30 from the rinsing phase of the preceding cycle and the characteristics of the net water.
At this point, the control unit 102 provides for processing both the measured values which are compared with predetermined reference values.
According to such an analysis, the control unit 102 controls the actuators 104, adapting, cycle by cycle, the flow rate of water delivered from the net 103.
As quality indicators of the solution present in the tank 30, like those of the net water as well, one or more of the following parameters can be taken : pH and/or conductivity and/or turbidity.
It has thus been seen that an improved rinsing station for tunnel machines according to the present invention achieves the purposes previously highlighted.
Indeed, the improved rinsing station for tunnel machines and the relative controlling method allow to reduce the consumption of net water in the rinsing phase without jeopardising the overall efficiency of the washing cycle, by calibrating the delivery of water from the network, cycle by cycle, according to indicating parameters of the quality of the net water and of the quality of the solution present in the tank 30 deriving from the rinsing of the preceding cycle and intended to be used in the pre-rinsing phase of the following cycle.
The improved rinsing station for tunnel machines of the present invention thus conceived can undergo numerous modifications and variants, all covered by the same inventive concept; moreover, all the details can be replaced by technically equivalent elements. In practice, the materials used, as well as their dimensions, can be any according to the technical requirements.

Claims

Rinsing station (21) for tunnel (100) dishwashers, said rinsing station (21) comprising rinsing spray nozzles (27) connected to a network for supplying net water (103), a pre-rinsing tank (30) for collecting a pre-rinsing solution connected to pre-rinsing spray nozzles (27'), said pre-rinsing solution comprising the net water (103) used in the rinsing phase of the preceding cycle and the substances removed from the rinsed dishes, so that the pre-rinsing phase of the following cycle takes place through the use of rinsing water used in the preceding cycle, characterised in that it comprises a control unit (102) connected on one side to sensors (101) for measuring the characteristics of said pre-rinsing solution contained in said pre-rinsing tank (30) and to means (105) for controlling the state of the net water (103) and on the other side connected to actuator means (104) for controlling the delivery of net water (103) to said spray nozzles (27) during the rinsing phase according to the values measured by said sensors (101) for measuring the characteristics of said pre-rinsing solution contained in said pre-rinsing tank and by said means (105) for controlling the state of the net water (103).
Rinsing station (21) according to claim 1 characterised in that said sensors (101) comprise at least a sensor chosen among the following types: pH reading sensors, reading sensors of the conductivity and reading sensors of the turbidity of said solution contained in said tank (30).
Method for controlling a rinsing station (21) according to any of the preceding claims characterised in that it cyclically comprises the steps of:
a) collecting in said tank (30) said pre-rinsing solution comprising the net water (103) used in the preceding rinsing cycle and the substances removed from the rinsed dishes;

b) measuring through said sensors (101) the characteristics of the solution collected in said tank (30) and transmitting said data to said control unit (102);

c) measuring the characteristics of the state of the net water (103) and transmitting said data to said control unit (102)

d) using said solution collected in said tank (30) during the pre-rinsing phase of a following washing cycle;

e) supplying to said spray nozzles (27) a predetermined quantity of net water (103) during the final rinsing phase of said following washing cycle according to said characteristics of the solution measured in said tank (30) and to the characteristics of the state of the net water (103).
Controlling method according to claim 3 characterised in that said phase of measuring through said sensors (101) said characteristics of the solution collected in said tank (30) comprises the phase of measuring Ph and/or conductivity and/or turbidity of said solution contained in said tank (30).
Controlling method according to claim 3 characterised in that it comprises the intermediate phase of comparing said characteristics of the solution collected in said tank (30) and said characteristics of the net water with reference values.
Tunnel dishwasher (100) comprising in succession from upstream to downstream following the movement of the dishes a pre-washing module, at least a washing module and a rinsing station (21) according to any of the preceding claims, being provided overflow channels from said tank (30) to said at least a washing module.