CN107073529B

CN107073529B - Cleaning unit for empty containers and corresponding method

Info

Publication number: CN107073529B
Application number: CN201580059569.8A
Authority: CN
Inventors: 克劳迪奥·贝莎吉; 安德里亚·斯特里兹
Original assignee: Gebo Packaging Solutions Italy SRL
Current assignee: Sidel End of Line and Tunnels Solutions SRL
Priority date: 2014-10-29
Filing date: 2015-10-15
Publication date: 2020-03-03
Anticipated expiration: 2035-10-15
Also published as: CN107073529A; BR112017008843A2; EP3015180A1; EP3015180B1; AR102446A1; WO2016066439A1; MX2017005520A

Abstract

The invention provides a cleaning unit (1) for cleaning empty containers (2), comprising a cleaning channel (3), a spraying device (8) and a control unit (9), wherein the containers (2) are conveyed in the cleaning channel (3), the cleaning channel (3) has a cleaning area (6) and also a final rinsing area (7), the final rinsing area (7) is arranged after the cleaning area (6) and the containers (2) are rinsed in the final rinsing area (7) with a rinsing liquid, such as water, the spraying device (8) is used for spraying the rinsing liquid on the containers (2) located in the final rinsing area (7), and the control unit (9) is used for controlling at least the operation of the spraying device (8). The cleaning unit is characterized in that it comprises at least one sensing unit (10), the at least one sensing unit (10) measuring the thermal effect of the spraying device (8) on the container (2) and sending corresponding information to the control unit (9). The invention also provides a corresponding method for controlling a cleaning unit.

Description

Cleaning unit for empty containers and corresponding method

Technical Field

The invention is in the field of washing units for empty containers, comprising a washing channel in which the containers are conveyed through a treatment zone, said containers being organized in a continuous line perpendicular to the direction of movement. The object of the invention is a cleaning unit and a method for controlling such a cleaning unit.

Background

In a standard washing unit, the containers are moved in a washing channel through a plurality of successive treatment zones, a pre-wash zone, then a first cleaning zone, a second cleaning zone and a final rinse zone. Each of these treatments is mainly based on liquids and chemical agents sprayed on or as a bath, wherein the containers are put into the bath and the chemical agents are sprayed when needed. The rinse stage typically uses a spray member to spray water on and in the container.

The containers are moved in the cleaning channel by a closed-loop conveyor, which comprises a vessel, wherein the containers can be inserted into the vessel. The containers are loaded onto the conveyor at the level of an input area and unloaded at the level of an output area, the processing area being located between the input area and the output area.

The internal conveyor moves in a certain direction in the cleaning path. In the internal conveyor, the containers are arranged in parallel lines perpendicular to the direction of movement, to process each container in the line simultaneously. Multiple lines are processed simultaneously in the purge path.

Such a cleaning unit is disclosed for example in EP 2727660. The overall consumption of process liquid is an important feature of the overall efficiency of such a cleaning unit. In common practice, the flow rate of the flushing liquid is fixed at a constant value corresponding to the worst possible operating conditions in relation to the liquid temperature, the external temperature, the container size, etc. This results in excessive consumption in any less demanding operating conditions. The object of the invention is to reduce the fresh water consumption during the rinsing phase.

Simply reducing the flow of sprayed water is not an acceptable solution. In fact, in some cases, the containers are subjected to a subsequent treatment step, in particular pouring the beverage, immediately after leaving the washing unit. The temperature of the container in this subsequent processing step can be critical. For example, the temperature of beer at the time of pouring is around 3 ℃. If the container is overheated, the thermal shock may easily break the container. If the container is overheated, the quality of the beverage also substantially changes. In this case, the temperature of the container as it exits the washing channel is directly dependent on the operation of the flushing device. Simply reducing the liquid flow in the final rinse area would then lead to hot containers and problems in such subsequent processing steps.

Disclosure of Invention

The invention therefore aims to propose a new type of washing unit which has a more efficient washing stage, saves washing liquid, but is still simple, easy to control and capable of providing a container at the desired temperature.

To achieve this object, the invention proposes to adjust the operation of the flushing phase on the basis of a thermal effect on the container produced by the flushing phase, said thermal effect corresponding to the resulting temperature of the container. The washing unit detects such thermal effects, for example as regards the temperature of the containers after they have been flushed, and adjusts the operating state of the flushing device.

According to the invention, a cleaning unit for cleaning empty containers (e.g. bottles or flasks) for liquid is provided, comprising a cleaning channel in which the containers are conveyed line by means of an internal conveying device for cleaning and further rinsing, a spraying device and a control unit, wherein the cleaning channel has a cleaning area for cleaning the containers with a liquid with a detergent or cleaning agent and also has a final rinsing area which is arranged after the cleaning area and for rinsing the containers with a rinsing liquid (e.g. water), the spraying device is used for spraying the rinsing liquid onto the containers located in the final rinsing area, and the control unit is used for controlling at least the operation of the spraying device.

The washing unit is characterized in that it further comprises at least one sensing unit for measuring the thermal effect of the spraying device on the container and sending corresponding information to the control unit, so that the control unit can guide the operation of the spraying device taking into account said information.

There is also provided a corresponding method for controlling a wash unit in which unit containers are cleaned and further washed in a final-wash phase by spraying means acting in a final-wash region of a wash channel of the wash unit, containers being organized in a line which advances in sequence in the wash channel, the method comprising

-measuring the thermal effect on the container during the final rinsing phase, and

-adjusting the operation of the spraying device based on the measured thermal effect.

Drawings

Further characteristics and advantages of the invention will be better understood from the following description of preferred embodiments, given by way of non-limiting illustration, with reference to the accompanying drawings, in which:

figure 1 shows a global view of the washing unit;

FIG. 2 is a more detailed view of the output area of the purge channel;

FIG. 3 is a diagram showing the interactions in the method;

FIG. 4 shows possible positions of the sensing unit at the level of the output area, an

Figure 5 is a graph showing the state of the spraying device and the associated temperature.

Detailed Description

A first object of the invention is a cleaning unit 1 for cleaning empty containers 2 for liquids, such as bottles or flasks, the cleaning unit 1 comprising

A washing channel 3, in which the containers 2 are conveyed line by a line 4 for cleaning and further rinsing by means of an internal conveying device 5, said washing channel 3 having a washing region 6 and also having a final rinsing region 7 arranged after the washing region 6, in which washing region 6 the containers 2 are cleaned with a liquid with a washing or cleaning agent, and in which final rinsing region 7 the containers 2 are rinsed with a rinsing liquid (e.g. water),

a spraying device 8 for spraying the rinsing liquid on the containers 2 in the final rinsing zone 7, an

A control unit 9 for controlling the operation of at least the spraying device 8.

In the washing zone 6, the container 2 is typically subjected to multiple showers or showers. In the rinsing zone 7, a rinsing liquid (e.g. water) is used to remove the chemical agents used during the cleaning step. The rinsing liquid is sprayed on the container 2 and/or in the container 2 and then collected again. The flushing liquid can then be recirculated and reused. The flushing liquid used in this flushing stage is therefore fresh or recirculated. For the purpose of the invention, i.e. in order to reduce the consumption of water, the spraying device 8 is a device which is mainly limited to operating with fresh flushing liquid. The flow of flushing liquid used by the spraying device 8 is controlled by at least one valve 19, the opening of which valve 19 can be adjusted in a continuous manner between two end positions.

According to the invention, the washing unit 1 also comprises at least one sensing unit 10, the sensing unit 10 being intended to measure the thermal effect of the spraying device 8 on the container 2 and to send corresponding information to the control unit 9, so that said control unit 9 can guide the operation of the spraying device 8 taking into account said information, in particular by guiding the operation of the spraying device 8 by changing the opening state of at least one valve 19 of said spraying device 8.

As will be described further below, the thermal effect of the flushing liquid is mainly due to the cooling of the container 2 and can therefore be measured with any corresponding parameters, among which: the temperature of the container 2, the temperature of the flushing liquid used, etc. As previously mentioned, according to the invention it is mainly proposed to introduce an adjustment of the operating conditions of the spraying device 8 consuming fresh rinsing liquid, based on the thermal effect on the container 2 resulting from the rinsing phase. In fact, the flow rate of the rinsing liquid sprayed by the spraying device 8 is increased or decreased based on the resulting temperature of the container 2.

According to a possible additional feature, at least one sensing unit 10 measures the temperature of the rinsing liquid after it has been sprinkled on the containers 2, in particular by measuring the temperature of the rinsing liquid in a collecting tank 16 in which the intermediate washing channel 3 is located in the final washing zone 7. This is one possibility to measure the thermal effect on the container 2 during the flushing phase.

According to another possible additional feature corresponding to another possibility for measuring the thermal effect on the containers 2 during the rinsing phase, the at least one sensing unit 10 directly measures the temperature of the containers 2 in or after the action of the rinsing liquid in the final rinsing zone 7. The sensing unit 10 is then positioned and oriented in the washing unit 1 to measure the temperature of a certain fixed detection area, which at least one container 2 should reach at least once after rinsing. When the movement of the internal conveyance device 5 is monitored, it is possible to know exactly when the container 2 has reached the detection area.

In some embodiments, at least one sensing unit 10 is located at an output area 11 of wash channel 3 after final flush area 7, where container 2 is withdrawn from inner delivery device 5 in final flush area 7. The containers 2 are transported through the cleaning tunnel 3 by means of the internal conveying device 5. They are loaded onto the internal transport device 5 at the input area 18 and unloaded at the output area 11. In the output area 11, the containers 2 are brought onto an external conveying device 12. It is proposed to position and orient the sensing unit 10 so that the measurement area reaches into this output area 11, preferably at the level of the transition between the inner and

outer conveyors

5, 12.

According to a possible additional feature, at least one sensing unit 10 is installed at the side of the washing channel 3 to be able to measure the temperature of the containers 2 located at the end of the line 4. Since the containers 2 are usually conveyed in the line 4 through the purge channel 3, it is simply advisable to position and orient the sensing unit 10 so that the sensing area corresponds to the end of the line 4. Such a position is also easy to achieve with existing wash units 1, since the sensing unit 10 may be fixed directly on e.g. the outer wall of the wash channel 3. Furthermore, in many existing purge channels 3, the end of the line 4 may be accessed directly.

According to another possible feature, the washing unit 1 comprises an external conveying device 12, the external conveying device 12 being intended to convey the containers 2 in one or more rows between the washing tunnel 3 and the subsequent treatment steps (such as filling), and at least one sensing unit 10 is mounted at the level of said external conveying device 12 to be able to measure the temperature of the containers 2 outside and after the washing tunnel 3. This makes implementation on existing wash units 1 easier. The outer transport device 12 may be movable in a direction perpendicular or parallel to the inner transport device 5. In the outer conveying device 12, the containers 2 can be conveyed in one or more rows parallel to the movement of the outer conveying device 12. The sensing unit 10 may, for example, be located above the external conveying device 12 and be oriented top-down to, for example, measure the temperature of the containers 2 in the middle row.

As already mentioned, the position of the containers 2 in the washing unit 1 is always known, either on the inner conveyor 5 or on the outer conveyor 12. Thus, the position of the container 2 and the temperature measurement can be synchronized: the temperature measured by the sensing unit 10 is taken into account in the regulation loop only when the container 2 is as desired in the detection area of the sensing unit 10. This helps to address the fact that the sensing unit 10 can operate continuously.

However, the line 4 may not be completely full and no container 2 reaches the desired detection area. This will cause irregularities in the regulation loop. Thus, in some embodiments, at least one sensing cell 10 comprises: a temperature measurement probe 13, such as an infrared-based probe; and a container detector 14, the container detector 14 for detecting whether the container 2 is present to enable verification that the temperature measured by the sensing unit 10 is the temperature of the container 2. Then, due to the synchronization, the moment at which the temperature has to be taken into account can be determined more accurately. In these embodiments, it is also possible to avoid taking into account the temperature measured when the container 2 is lost.

According to another possible additional feature, the control unit 9 comprises a storage unit 15 for storing information received from the sensing unit 10. As will be explained in more detail later, this allows to store the measured temperature when corresponding to the actual container 2, to reuse this value for the regulation loop in the absence of the container 2. Furthermore, this storage unit 15 can be used for auto-tuning purposes and is mainly used for storing information associated with the status of the spraying device 8 and the resulting thermal effect on the container 2.

A second object of the invention is a method for controlling a wash unit 1, in which unit containers 2 are cleaned in said wash unit 1 and are further washed in a final wash phase by a spraying device 8 operating in a final wash zone 7 of a wash channel 3 of said wash unit 1, the containers 2 being organized in a line 4 which advances in sequence in said wash channel 3.

According to the invention, the method comprises

Measuring the thermal effect on the container 2 during the final flushing phase, and

-adjusting the operation of the spraying device 8 on the basis of the measured thermal effect, in particular increasing the flow rate of the spraying device 8 if insufficient thermal effect on the container 2 is detected, or decreasing the flow rate if too high thermal effect on the container 2 is detected.

The operation of the regulating spraying device 8 mainly consists in changing the opening of at least one control valve 19. It should be noted that the adjustment of the flushing liquid flow may be performed only for the fresh water circuit and/or the used water circuit.

As mentioned before, the thermal effect can be evaluated, for example, by directly measuring the temperature of the container 2, or by measuring the temperature of the used flushing liquid. Thus, in some embodiments, measuring the thermal effect on the tank 2 in the final washing phase is achieved by measuring the temperature of the washing liquid after its action on the tank 2, in particular by measuring the temperature of the used washing liquid collected in a collecting tank 16, said tank 16 collecting said washing liquid after its action.

According to an additional or alternative feature, measuring the thermal effect on the containers 2 during the final rinse phase is achieved by measuring the temperature of the containers 2 after the action of the rinsing liquid in the final rinse zone 7 or in the output zone 11 of the rinse channel 3 or even at the level of the external conveying device 12 of the rinse unit 1, wherein the external conveying device 12 of the rinse unit 1 conveys the containers 2 in one or more rows after said output zone 11.

In some embodiments, measuring the temperature of the containers 2 is performed after the containers 2 have left the final rinse zone 7, and the operation of the spraying device 8 is adjusted taking into account the time period required for the containers 2 to move from the final rinse zone 7 to the zone where their temperature is measured, in particular by correlating the instantaneous operation of the spraying device 8 with the temperature measured only after said time period has elapsed. Due to the time required for the container 2 to move from the area of action of the sprinkler device 8 to the area of action of the sensing unit 10, associating the temperature at a certain moment in time with the state of the sprinkler device 8 at the same moment in time will lead to a wrong regulation loop.

As previously mentioned, the movement of the inner conveyor 5 and the movement of the outer conveyor 12 are constantly monitored, which makes it possible to monitor and take into account the time between spraying and measurement. Thus, according to another possible characteristic, the time period required for the container 2 to move from the final rinsing zone 7 to the zone of which the temperature is measured is calculated on the basis of the speed of the conveying means of the container 2 moving between these two zones (the inner conveying means 5 alone, or both the inner conveying means 5 and the outer conveying means 12).

In order to deal with the absence of a container 2 in the intended sensing area of the sensing unit 10, and according to another possible feature, the method comprises

-detecting the presence of the container 2, and,

in case the presence of a container 2 is detected, the measured thermal effect is used to control the operation of the spraying device 8 and to store the measured value in the memory unit 15, and,

in the absence of a container 2, recall the previously stored measurement values for controlling the operation of the spraying device 8.

According to another possible characteristic of the method, it consists in monitoring the relationship between the operating state of the spraying device 8 and the thermal effect generated on the container 2, and finally in further considering this relationship on the basis of a target thermal effect (in particular a target temperature of the container 2) when controlling the operation of the spraying device 8.

In fact, the adjustment of the sprinkling device 8 can be based on the following principle: the flushing flow is increased stepwise until the temperature of the container 2 decreases to a target range, or the flushing flow is decreased until the temperature increases to a target range. One of the advantages of this working principle is that it can be used even without a model of the thermal reaction itself that takes place in the final rinse zone. Another principle is to use a predictive model of the thermal reaction, in which the operating state of the sprinkler 8 is directly related to the thermal effect on the container 2. However, it is difficult to build a reliable prediction model, mainly because the parameters to be considered are quite numerous. Thus, in some embodiments of the method, it is proposed to construct the model by collecting data relating both to the operating conditions of the spraying device 8 and to the thermal effects produced by the container 2. This model can then be used to reduce the time required to reach the optimum operating state of the spraying device 8 for the target temperature of the container 2.

In the embodiment shown in the figures, the cleaning unit 1 treats containers 2 of beverages or other liquids. The container 2 may be made of, for example, plastic or glass.

The container 2 moves from the left side to the right side in fig. 1 in the cleaning unit 1. The washing unit 1 has a washing channel 3, in which washing channel 3 the containers 2 are cleaned. The dirty containers 2 enter the cleaning channel 3 at the input region 18 of said channel 3 and are moved by the internal conveying device 5 to the output region 11. The internal conveying device 5 receives the containers 2 at the level of the vessel 17, the vessel 17 having a corresponding shape and in the vessel 17 the containers 2 can be inserted and the containers 2 can be further held during the cleaning of the cleaning channel 3.

Since the internal conveying device 5 has a plurality of pockets 17 arranged next to one another in the line 4 perpendicular to the movement of the internal conveying device 5, a plurality of containers 2 are processed simultaneously. The containers 2 are thus organized in the washing channel 3 in a plurality of parallel lines 4 perpendicular to the movement of the internal conveying means 5.

In the cleaning tunnel 3, the containers 2 are moved through a plurality of zones for treating the containers 2. In particular, as shown in fig. 1, the containers 2 are brought into a series of tanks filled with a liquid containing chemical reagents with an internal conveying device 5. Fig. 1 shows two treatment tanks one after the other in the cleaning zone 6 to achieve a pre-cleaning and then a final cleaning.

As previously mentioned, in some cases, these baths heat the container 2 due to the temperature or chemical activity of the liquid in the tank. This may be problematic in later stages of the process where it is required that the container 2 has a temperature within a certain range, for example stages where the container 2 is filled or filled with an aerated liquid, such as beer. Moreover, in some cases, the container 2 is also dedicated to containing beverages or special chemical products. Therefore, for hygienic, cleaning and/or chemical purposes, it is also necessary to arrange a rinsing step of removing the chemical agent of the cleaning liquid from the container 2.

For these reasons, the cleaning channel 1 also has a final rinsing zone 7, mainly for removing the chemical cleaning agent from the container 2 and cooling down the container 2. A spraying device 8 is installed in the rinsing zone 7 and sprays rinsing liquid on the containers 2 and/or in the containers 2. The spraying device 8 can have a plurality of spraying elements which act one after the other on the container 2. The flushing liquid can be sprayed into the container 2 oriented upside down in the internal conveying device 5.

Water is preferably used as the rinsing liquid. The rinsing liquid has a thermal effect on the container 2 which substantially corresponds to the temperature change of the container 2 caused by the rinsing liquid sprayed and flowing thereon. The heating effect of the flushing is usually mainly the temperature of the cooling vessel 2.

The rinsing liquid is sprayed on the containers 2 in the final rinsing zone 7. The final rinsing zone 7 also has a collection gutter 16 located below the internal conveying device 5, the collection gutter 16 being used to collect the rinsing liquid after it has been sprayed on the containers 2. Since the rinsing liquid has a cooling thermal effect on the containers 2, the rinsing liquid is heated and the temperature of the rinsing liquid collected in the collecting sump 16 in the final rinsing zone 7 is higher than the temperature of the rinsing liquid not yet sprayed on the containers 2. The thermal effect of the rinsing liquid on the container 2 can therefore be evaluated by measuring the temperature of the used rinsing liquid collected in the collection tank 16 and comparing it with the temperature of the rinsing liquid before spraying.

Of course, the thermal effect of the flushing phase can also be evaluated by directly measuring the temperature of the container 2 itself.

In order to optimize the use of the flushing liquid, it is proposed to adjust the operating state of the spraying device 8 on the basis of a thermal effect on the container 2, which is evaluated, for example, by measuring the temperature of the container 2 itself or by measuring the temperature of the used flushing liquid in the collecting tank. Preferably, the minimum flushing liquid flow is greater than zero: reducing the flow of flushing liquid to zero cannot be achieved but is stopped at a certain minimum value to ensure that the flushing liquid always flows in some way in any operating state of the washing unit 1.

To achieve this, the washing unit 1 comprises at least one sensing unit 10 for measuring such thermal effects, which is mainly used to assess whether the treated container 2 is overheated or overcooled or within a predetermined target range. This measurement is sent to the control unit 9 of the washing unit 1, which control unit 9 compares the measurement with the target and adjusts the behavior of the spraying device 8, in particular the spraying device 8 consuming new rinsing liquid, accordingly. Thus, the sensing unit 10 is preferably capable of measuring the temperature of the container 2, or another related characteristic, such as the temperature of the used flushing liquid. The sensing unit 10 is thus able to measure the thermal effect on the container 2 during the flushing phase by measuring the heating of the flushing liquid or by measuring the cooling of the container 2.

The spraying device 8 usually comprises more than one spraying element acting on the containers 2 one after the other. For water saving purposes, only the last spray element uses clean and fresh water, while the other spray elements use recycled flushing liquid. In this case, the consumption of the new flushing liquid depends only on the operating state of the last spray element. Preferably, therefore, the adjustment of the operating condition of the spraying device 8 is mainly by adjusting the operating condition of those elements of said spraying device 8 (in particular of said last spraying member) which use only new rinsing liquid.

In the case of measuring the thermal effect by measuring the temperature of the containers 2, the corresponding sensing unit 10 can be placed so as to be able to measure it directly in the final rinse zone 7 or even after the treatment line (for example in the output zone 11 of the washing tunnel 3, or at the level of the external conveyor 12 that moves the containers 2 from the washing tunnel 3 to the subsequent treatment machine).

As previously mentioned, the containers 2 are transported in the washing channel 3 in parallel lines 4 generally perpendicular to the movement of the internal transport device 5. Thus, the instantaneous treatment of each container 2 of a particular line 4 is generally the same. In some cases, at least one sensing unit 10 measures the temperature of a single container 2 and regulates the flow of flushing liquid throughout the line.

However, the pocket 17 targeted by the sensing unit 10 may be empty, for example at the beginning of a processing batch, if the container 2 has fallen down in the input area 18 or even some containers 2 are lost. Even in such a case of loss of the container 2, the sensing unit 10 will still generate a signal corresponding to the measured temperature, which in turn corresponds to the temperature of the other objects than the container 2: the vessel 17, the internal conveying means 5 or even another internal element of the washing channel 3 which is present in the examination area. Such a measurement cannot be taken into account during the adjustment of the rinsing phase because it does not represent a thermal effect of the rinsing liquid.

In order to solve this problem, it is proposed to implement a detection step of detecting the presence or absence of the container 2 when evaluating the thermal effect by means of a sensing unit 10 capable of measuring the temperature of the container 2. To this end, the sensing unit 10 may further include a container detector 14. In this case, the signal sent by the sensing unit 10 to the control unit 9 comprises information relating to the temperature of the containers 2 and also information relating to the presence or absence of the containers 2 in the temperature detection area of the sensing unit 10, wherein the information relating to the temperature of the containers 2 generally corresponds directly to the thermal effect of the flushing phase. The processing of the information about the temperature by the control unit 9 will then depend on the signal corresponding to the presence or absence of the container 2.

It should be noted here that the containers 2 are treated during the cleaning process via line 4, followed by line 4. Furthermore, the sensing unit 10 is generally static and mounted to measure the temperature in a predetermined area in which the container 2 is moved. Thus, a first temperature detected by the sensing unit 10 corresponds to a container 2 at a certain position in the first line 4, while a second temperature corresponds to a container 2 at the same position in the subsequent line 4, and so on. The sensing unit 10 generally detects the temperature of the containers 2 belonging to the continuous line 4. The absence of a container 2 in the sequence of lines 4 may therefore lead to incorrect adjustment of the operating state of the spraying device 8. It is therefore proposed to add a storage unit 15, in which storage unit 15 the measurements can be stored and recalled as described below.

If the sensing unit 10 detects the presence of the container 2 when measuring the temperature, the control unit 9 uses said temperature to adjust the operating state of the spraying device 8, if necessary. This value is also stored in the memory unit 15, possibly by resetting the currently stored value. The regulating circuit only takes into account the values stored in the storage unit 15 if the sensing unit 10 detects the absence of a container 2 when measuring the temperature.

When the line 4 processes the containers 2 following the line 4, the temperature measurement, the container 2 detection and the calculation of the resulting required adjustment can be synchronized with the speed of movement of the internal conveying means 5. By taking into account the movement of the internal transportation means 5, it is possible to know exactly when the container 2 is expected to reach the measurement area of the sensing unit 10. For this precise moment, the temperature sensed by the sensing unit 10 and the detection of the container detector 14 are processed as described earlier.

The use of the container detector 14 is particularly useful for embodiments in which the thermal effect of the flushing phase is directly measured, typically by measuring the temperature of the container 2 located in a predetermined position in the line 4. However, the use of the container detector 14 may also be useful for embodiments that measure thermal effects by measuring the temperature of the rinsing liquid collected in the collection tank 16. For such an embodiment, for example, a completely empty operating state of the line 4 can be recognized, which means that the operating state of the spraying device 8 should not be adjusted taking into account the temperature of the liquid in the collecting tank 16.

Fig. 4 focuses on the output area 11 of an embodiment in which the sensing unit 10 is located at the level of said output area 11, the containers 2 being taken from the inner conveying means 5 at the output area 11 and placed on the outer conveying means 12. In this embodiment, the sensing unit 10 has the form of a sub-assembly in which both the temperature measurement probe 13 and the container detector 14 are integrated, for example one above the other. The sensing unit 10 is mounted at the side of the output area 11 to detect the output of the pocket 17 at the end of the line 4. The containers 2 are guided as the containers 2 leave the vessel 17 and the wall between the sensing unit 10 and the first container 2 has an opening in a direction corresponding to the direction of the line 4, through which the temperature can be measured and the containers 2 can be detected. This embodiment is very easy to implement and has little impact on the design of the rest of the washing unit 1.

An external conveying device 12 conveys the containers 2 from the output region 11 of the washing tunnel 3 to a subsequent processing machine, for example a filler. The movement of the outer transport device 12 may be parallel or perpendicular to the movement of the inner transport device 5. Typically, during this conveying phase, the containers 2 are conveyed in a single file parallel to the movement of the external conveying device 12.

The sensing unit 10 may also be mounted such that it measures the temperature of the container 2 as the container 2 is moved onto the external conveying device 12. This makes it easier to work with the container 2 which is usually located in the middle of the line 4, for example in the wash channel 3.

The adjustment of the spraying device 8 will now be explained. The spraying device 8 essentially consists of a set of spraying elements which spray and spray rinsing liquid in or on the containers 2. The control unit 9 uses the observed thermal effect as an input to regulate the flow of flushing liquid. If the thermal effect is too high, corresponding to a temperature of the container 2 below a predetermined target, the flow rate of the flushing liquid is reduced, preferably to a predetermined value. In another case, if the thermal effect corresponding to a temperature of the container 2 above the predetermined target is too low, the flow rate of the flushing liquid is increased, preferably to a predetermined value. Of course, when the thermal effect is within the target range, the flow rate of the rinsing liquid is not adjusted, but is merely maintained. The comparison of the measured thermal effect with the target range is preferably synchronized with the movement of the container 2 and is performed each time a new line 4 arrives and is analyzed. Furthermore, it is preferred that the minimum flow of the rinsing liquid is larger than zero and that at least such a small flow of rinsing liquid is maintained. This ensures that the detergent is removed from the interior of the container 2 in any case.

By such a working principle, the flow of flushing liquid is adjusted stepwise until the target is reached. Thus, an optimal flow of rinsing liquid can be achieved even if the relation between the rinsing flow and the final temperature of the container 2 is unknown.

As mentioned above, in some embodiments, the thermal effect of the sprinkler 8 is measured only after the container 2 has left the final rinse zone 7. The temperature of the container 2 therefore does not correspond to the operating state of the spraying device 8 occurring simultaneously. Therefore, adjusting the flow rate of the flushing liquid at a certain moment cannot be based on a thermal effect measured simultaneously: the temperature of the container 2 cannot be used to regulate the simultaneous flow of flushing liquid.

In order to solve this problem, it is proposed that the control unit 9 takes into account the duration of time required for the container 2 to move from the final rinsing zone 7 to the position where the temperature is measured.

For purposes of the following description, this duration is defined as "D". Let us name the moment at which the control unit 9 adjusts the operating state of the spraying device 8 as "M". The container 2 subjected to this particular operating condition will be measured only after the passage of time D from instant M, i.e. at instant M + D. The feedback loop of the control unit 9 therefore advantageously takes into account the time D and, when adjusting the state of the spraying device 8 at the instant M, it analyzes the result of this adjustment only at the instant M + D, i.e. as soon as the container 2, which has been rinsed by the spraying device 8 in this particular operating state, reaches the temperature measurement zone of the at least one sensing unit 10.

Thus, after a change in the operating state of the spraying device 8, which is mainly due to the flow rate of the flushing liquid, said state can remain unchanged for a period of time corresponding to the duration D required for the container to move between the two aforementioned zones.

As previously mentioned, in some embodiments, the control unit 9 varies the operation of the spraying device 8 based on predefined increments and measured thermal effects until the target is reached. However, when so performed, it may be long to obtain a state corresponding to a target thermal effect on the container 2. In order to reduce the time required to reach the target, benefits may be derived from completed measurements. The chart in fig. 5 shows three columns: the left column corresponds to the instantaneous state of the sprinkler 8; the middle column corresponds to the temperature of a row of containers 2 measured simultaneously; the column on the right shows the information that can be constructed with these two values. Each row corresponds to a time increment, which means that each row corresponds to the moment at which the line 4 reaches the measurement area of the sensing unit 10.

In this schematic, the final rinse zone 7 and the measurement zone are separated by three containers 2, and the process is as follows:

at time 1, the state of the spraying device is S1, in the following order time 2 is state S2, time 3 is state S3;

at time 4, the state of the spraying device is S4, and the container 2 subjected to S1 can now be measured, which results in T1. The control unit 9 may then conclude that if the status of the spraying device 8 is S1, the temperature will be T1;

at time 5, the state of the spraying device 8 is S5, and the container subjected to S2 can now be measured, which results in T2. The relationship between S2 and T2 may be stored;

at time 6, state S6. When the state is S3, a temperature measurement is taken of the container 2 in the final rinse zone, yielding information that S3 results in T3, and so on.

Thus, by varying the operation of the sprinkler 8, the control unit 9 can then gradually collect some data to be used as a predictive model relating the state of the sprinkler 8 to the resulting thermal effect. In order to collect such predictive data more quickly, the state of the spraying device 8 can be changed even during the duration D of the waiting of the control unit 9 for the container 2.

This principle of establishing a predictive model may also be applied to embodiments in which the thermal effect measurement and the flushing are synchronized and embodiments in which the sensing unit 10 measures the temperature of the flushing liquid collected in the collection tank 16.

The control unit 9 may use the memory unit 15 to store such predictive data relating to the correlation between the state of the spraying device 8 and the resulting thermal effect on the container 2. This data can then be used to control the operation of the sprinkler 8 based on the target thermal effect and reach the target faster than by gradually adjusting the state.

Due to this description it can be understood that, according to the invention, the flushing phase is regulated according to the thermal effect it generates on the container 2, which is temperature-dependent. This may directly contribute to a sufficient saving in connection with the new flushing liquid in a very simple manner, since the thermal effect is directly used as an input to the feedback loop, instead of e.g. the temperature of the new flushing liquid, the temperature of the container 2 before flushing, the pH status, etc.

Of course, from a general point of view, the regulation of the spraying flow rate of the spraying device 8 can also be based solely on the detection of the presence or absence of the container 2 without any temperature measurement: if no container 2 is detected, the flow rate of the flushing liquid is set to its minimum value; if the container 2 is detected, the flow rate is set to its standard value.

While specific embodiments of the invention have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of the invention which is to be given the full breadth of the claims appended and any and all equivalents thereof including any and all combinations of features thereof.

Claims

1. A cleaning unit (1) for cleaning an empty container (2) for a liquid, the cleaning unit (1) comprising:

a washing channel (3), in which washing channel (3) the containers (2) are conveyed by means of an internal conveying device (5) line (4) after line (4) for cleaning and further rinsing, the washing channel (3) having a washing region (6) for cleaning the containers (2) with a liquid with a washing or cleaning agent and also having a final rinsing region (7), the final rinsing region (7) being arranged after the washing region (6) and in which final rinsing region (7) the containers (2) are rinsed with a rinsing liquid,

a spraying device (8) for spraying the rinsing liquid on the containers (2) in the final rinsing zone (7), and

a control unit (9) for controlling at least the operation of the spraying device (8),

the cleaning unit (1) is characterized in that

The washing unit (1) further comprises at least one sensing unit (10), the sensing unit (10) being adapted to measure the thermal effect of the spraying device (8) on the container (2) and to send corresponding information to the control unit (9), so that the control unit (9) can guide the operation of the spraying device (8) by adjusting the flow rate of the rinsing liquid taking into account the information.

2. Washing unit (1) according to claim 1, wherein the at least one sensing unit (10) measures the temperature of the rinsing liquid after it has been sprayed on the container (2).

3. Washing unit (1) according to any of claims 1 or 2, wherein the at least one sensing unit (10) measures the temperature of the container (2) directly after the action of the rinsing liquid in the final rinsing zone (7) or after the final rinsing zone (7).

4. A washing unit (1) according to claim 3, wherein the at least one sensing unit (10) is located at an output area (11) of the washing channel (3) after the final rinse area (7), the container (2) exiting the internal conveying means (5) at the output area (11).

5. Washing unit (1) according to claim 3, wherein said at least one sensing unit (10) is mounted at the side of the washing channel (3) to be able to measure the temperature of the containers (2) located at the end of the line (4).

6. A washing unit (1) according to claim 3, wherein the washing unit (1) comprises an external conveying device (12), the external conveying device (12) being used to convey the containers (2) in one or more rows between the washing tunnel (3) and the subsequent treatment steps, and the at least one sensing unit (10) is mounted at the level of the external conveying device (12) to be able to measure the temperature of the containers (2) outside and after the washing tunnel (3).

7. Washing unit (1) according to claim 1, wherein the at least one sensing unit (10) comprises: a temperature measurement probe (13); and a container detector (14) for detecting the presence of a container (2) to enable verification that the temperature measured by the sensing unit (10) is the temperature of the container (2).

8. Washing unit (1) according to claim 1, wherein the control unit (9) comprises a memory unit (15), the memory unit (15) being adapted to store information received from the sensing unit (10).

9. Cleaning unit (1) according to claim 7, wherein the temperature measurement probe comprises an infrared-based probe.

10. A method for controlling a washing unit (1), in which washing unit (1) unit containers (2) are cleaned and further washed in a final-wash phase by means of spraying devices (8) acting in a final-wash zone (7) of a washing channel (3) of the washing unit (1), the containers (2) being organized in lines (4) which advance one after the other in the washing channel (3),

the method comprises the following steps of,

-measuring the thermal effect of the final flushing phase on the container (2), and

-adjusting the operation of the spraying device (8) by adjusting the flow of flushing liquid based on the measured thermal effect.

11. Method according to claim 10, wherein the measurement of the thermal effect of the final rinsing phase on the container (2) is achieved by measuring the temperature of the rinsing liquid after its action on the container (2).

12. Method according to claim 10 or 11, wherein the measurement of the thermal effect of the final rinsing phase on the containers (2) is achieved by measuring the temperature of the containers (2) after the action of the rinsing liquid.

13. Method according to claim 12, wherein measuring the temperature of the containers (2) is performed after the containers (2) have left the final rinse zone (7), and the operation of the spraying device (8) is adjusted taking into account the time period required for the containers (2) to move from the final rinse zone (7) to the zone where the temperature of the containers (2) is measured.

14. A method according to claim 13, wherein the time period required for the container (2) to move from the final rinse zone (7) to the zone where the temperature of the container (2) is measured is calculated based on the speed of a conveyor moving the container (2) between the two zones.

15. The method of claim 10 or 11, further comprising

-detecting the presence of said container (2), and,

-in case the presence of the container (2) is detected, using the measured thermal effect to control the operation of the spraying device (8) and storing the measured value in a storage unit (15), and,

-in the absence of the container (2), recall the previously stored measurement values to control the operation of the spraying device (8).

16. Method according to claim 10 or 11, further comprising monitoring the relation between the operating state of the spraying device (8) and the resulting thermal effect on the container (2).