EP2850991A1 - Device for dosing a liquid process chemical - Google Patents

Abstract

Apparatus for metering a liquid process chemical (2) from a storage container (4) into a washing compartment (3) of a program-controlled automatic washer-disinfector, with a compressed air line (10) opening into the washing compartment (3) of the machine and to the compressed-air line (10) connected intermediate container (5), which is equipped for a fluidic connection to the reservoir (4).

Description

The invention relates to a device and a method for dosing a liquid process chemical from a reservoir into a washing compartment of a program-controlled cleaning and / or disinfecting machine.

Program controlled cleaning and / or disinfecting machines are well known in the art. A separate documentary proof is therefore not required at this point.

Previously known cleaning and / or disinfection machines are used for cleaning and / or disinfecting items to be cleaned and / or disinfected and have for this purpose a washing room that receives the items to be cleaned and / or disinfected rinse in the intended use case. Typical cleaning and / or disinfecting machines in the sense of the invention are, in particular, washing machines or dishwashing machines, as well as laboratory dishwashers, gastronomy dishwashers, cleaning machines for medical devices and / or similar devices.

To achieve an optimized cleaning, disinfection and / or drying result, liquid process chemicals are used, which are supplied to the washing compartment of the cleaning and / or disinfecting machine in the course of a cleaning, disinfection and / or drying process. Such process chemicals are, for example, cleaning and / or disinfection chemicals which, depending on the program control, are used at different times and metered into the washing compartment of the automatic cleaning and / or disinfecting machine. Such metering of a process chemical is typically subject to continuous monitoring.

For the purpose of dosing liquid process chemicals dosing devices have become known from the prior art, which have a suction lance and a metering pump fluidly connected to the suction lance. When used as intended, the suction lance extends into a reservoir storing the process chemical. In one operation of the Metering pump, the process chemical is sucked through the suction lance and conveyed to the pressure side of the metering pump, from where it passes through a corresponding supply line in the washing compartment of the cleaning and / or disinfecting machine. On the pressure side of the metering pump, metering quantity monitoring is typically provided, by means of which the quantity of process chemical conveyed by the metering pump is monitored, so that compliance with predetermined metered quantities is ensured.

The metering pumps are typically peristaltic pumps or bellows stroke pumps. Such pumps prove to be advantageous in that they can ensure a comparatively accurate metering of the promoted process chemical at the same time high conveying speed.

Although prior art metering pumps have proven themselves in everyday practice, they are not free from disadvantages. Thus, the dosing pumps used in prior art dosing devices adhere to the principal problem of wear. This is due to the design and leads to the fact that it requires regular maintenance for proper operation. Such maintenance is typically carried out annually and previously known from the prior art metering pumps are regularly replaced due to wear. This is perceived by the user as disadvantageous.

It is based on the above, the object of the invention to further develop a device for dosing a liquid process chemical of the type mentioned in that a low-wear operation and thus a longer life is possible with high dosing accuracy and high conveying speed.

To solve this problem, the invention proposes a device for dosing a liquid Prozesschemikalie from a reservoir in a washing compartment of a programmable cleaning and / or disinfection machine, with an opening into the washing compartment of the machine compressed air line and connected to the compressed air line intermediate container for a fluidic connection to the reservoir is equipped.

The device according to the invention works in contrast to previously known metering pumps not mechanically but pneumatically. Wear-related wear and consequent failures are thus avoided in an advantageous manner.

The device according to the invention has a compressed air line. This compressed air line is connected at one end to a compressed air source. At the other end, the compressed air line discharges into the washing compartment of the machine.

The device according to the invention also has an intermediate container. This intermediate container is fluidly connected to the compressed air line. This makes it possible to generate in the intermediate container either a negative pressure or an overpressure.

The intermediate container in turn is equipped for a fluidic connection to the reservoir storing the process chemical. In the intended use case, this allows a fluidic connection between the reservoir on the one hand and the intermediate container on the other hand, so that process chemicals can flow from the reservoir into the intermediate container.

The reservoir is typically a user-replaceable canister with a canister volume of several liters. If the amount of process chemical stored by such a canister is used up, replace the empty canister with a new one, ie with a process chemical filled canister. For this purpose, the fluidic connection between the canister and the intermediate container to solve. Then the canister exchange can be made and the new canister filled with process chemical can be connected to the intermediate container.

The device according to the invention makes it possible to convey process chemicals pneumatically and therefore basically contactlessly from the storage container into the washing compartment of the cleaning and / or disinfecting machine. For this purpose, pressure pulses are generated and conveyed through the compressed air line in the direction of the washing compartment of the machine. As a result of this compressed air delivery, a negative pressure is generated in the fluidically connected to the compressed air line intermediate container. This is because the compressed air delivery in the compressed air line with respect to the intermediate container to a kind of "entrainment" results, as a result, air is sucked out of the intermediate container and conveyed via the compressed air line into the washing compartment, whereby it comes in the intermediate container to form a negative pressure.

The intermediate container is in fluid communication with the reservoir. As soon as it comes to the formation of a negative pressure in the intermediate container, this fluidic connection is opened. It comes as a result to a pressure balance between the intermediate container on the one hand and reservoir on the other hand, which has an influx of process chemical from the reservoir into the intermediate container result.

In a next step, the fluidic connection between the reservoir and intermediate container is closed again. In addition, the compressed air pulses are no longer conveyed by a corresponding valve change in the washing compartment of the machine, but in the intermediate container. It comes as a result to the formation of an overpressure within the intermediate container. The intermediate container in turn is in fluid communication with the washing compartment. As soon as there is an overpressure in the intermediate container, this fluidic connection between the intermediate container and the washing compartment is opened, as a result of which the overpressure prevailing in the intermediate container leads to an overflow of the process chemical located in the intermediate container into the washing compartment of the automatic machine.

The intermediate container thus has three connections, namely a first connection for the fluidic connection of the intermediate container to the reservoir, a second connection for the fluidic connection of the intermediate container to the compressed air line and a third connection for the fluidic connection of the intermediate container to the washing compartment. The intermediate container provides a, in particular a single chamber, from which all three connections go out. This chamber thus serves on the one hand for temporary storage of the liquid process chemical, on the other hand, it is set up that compressed air can flow into it, whereby the compressed air can act directly on the process chemical and push it out of the chamber through the third port in the dosing to the washing compartment.

The second connection of the intermediate container is preferably arranged higher in gravity relative to the intermediate container than the third connection of the intermediate container. This allows the process chemical level in the tundish to always be set so that the second port is above the level of the process chemical, while the third port is typically below the level of the process chemical. In this way it is avoided that over the second connection process chemical is sucked. In particular, the second connection in a cover-side region of the intermediate container and the third connection in a near-bottom region of the intermediate container are arranged. Preferably, the first connection of the intermediate container is arranged higher gravity on the intermediate container than the third connection of the intermediate container, and is in particular arranged in a cover-side region of the intermediate container.

The advantage of the metering device according to the invention is, in particular, that it does not work mechanically, but pneumatically and consequently basically wear-free. In particular, actuators exposed to the process chemistry are avoided. In that regard, in contrast to the prior art, maintenance work can be completely dispensed with. In addition, the entire device does not work in contact with the media except for the lines and valves provided for guiding the process chemical. All structural components of the compressed air line do not come into contact with the process chemical to be pumped into the flushing chamber so that wear-related wear due to possibly aggressive chemicals is completely avoided. The result is a long life of the entire device.

In contrast to previously known mechanical metering pumps, there is also the advantage that process chemicals can be introduced into the flushing chamber at a delivery speed of approximately 20 times, and this with a metering accuracy that is well below the legally prescribed 5% tolerance limit with approximately 1% tolerance. Thus, the metering device according to the invention proves to be much more effective than the previously known from the prior art devices.

For the fluidic connection of the intermediate container to the compressed air line comes in accordance with a further feature of the invention, a vacuum nozzle is used. This is integrated into the compressed air line, bringing the intermediate container under Intermediate connection of the vacuum nozzle is connected to the compressed air line. As part of the compressed air line, the vacuum nozzle provides a main channel and a secondary channel branched off from it. About this sub-channel of the intermediate container is fluidically connected to the main channel and thus the compressed-air line fluidically. Typically, the main channel and the sub-channel are formed orthogonal to each other, thus forming a T-shaped configuration. In the intended use of the transfer of process chemical from the reservoir into the intermediate container of the main channel provided by the vacuum nozzle is traversed by compressed air. This leads to an air outlet from the intermediate container, wherein the air coming from the intermediate container flows through the auxiliary channel of the vacuum nozzle.

In the intended use of transferring process chemical from the intermediate container into the washing compartment, the fluidic connection between the vacuum nozzle on the one hand and the washing compartment on the other hand is closed. As a result, the compressed air flowing into the vacuum nozzle can not pass through the main channel on the output side of the vacuum nozzle. The introduced into the vacuum nozzle compressed air is rather dissipated via the secondary channel, in the intermediate container, as a result, it comes here to form an overpressure in the manner already described above.

In order to specify the compressed air paths in the manner described above, two directional control valves are provided according to a further feature of the invention. In this case, a first directional control valve of the vacuum nozzle upstream in the flow direction and a second directional control valve is connected downstream of the vacuum nozzle in the flow direction. The vacuum nozzle is therefore arranged between the two directional control valves.

The reservoir is connected to the intermediate container via a guide line for guiding the process chemical. The intermediate container is connected in terms of flow in the same way to the washing compartment. It is preferably provided that in each case a check valve is integrated into the line between the reservoir and the intermediate container as well as in the line between the intermediate container and the washing compartment. The check valves ensure that no process chemical from the intermediate container can flow back into the reservoir or from the washing room back into the intermediate container.

An advantage of the construction according to the invention is further in this context that due to a pressure prevailing in the intermediate container a drip-free Sauglanzenwechsel and thus a reservoir exchange can be made.

As already described, the intermediate container is fluidically connected to the washing compartment. For this purpose, there is a dosing line emanating from the third connection of the intermediate container. Preferably, this line opens into the compressed air line, in particular it opens into Spülraumeinlassnähe in the compressed air line. The mouth is located between the second directional control valve and the Spülraumeinlass. At the end of a dosing process, the second directional control valve is opened again, as a result of which the compressed air no longer flows via the auxiliary channel into the intermediate container, but via the main channel into the washing compartment. Instead of an overpressure in the intermediate container thereby now again a negative pressure, whereby the dosing process is stopped and the intermediate container is refilled with process chemical from the reservoir. In addition, the compressed chemical in the compressed air line directly before the Spülraumeinlass, namely between the mouth of the dosing into the compressed air line and the Spülraumeinlass process chemical is conveyed into the wash compartment. In this way, this area near the Spülraumeinlass is advantageously completely removed from the process chemical. This ensures that the process chemical can always get into the washroom only in the desired amount specified and at the given time and thus no unwanted dripping of individual drops of the chemical process in the washroom. This achieves a better cleaning result with high dosing accuracy and process reliability.

Due to the inventive design of the metering device is for the period in which the second directional control valve is kept closed, and the metered process fluid quantity, a relationship that is linear with high accuracy. This allows a very high dosing accuracy can be achieved at the same time high dosing. The dosage is thus preferably timed, i. by setting a time duration in which the second directional control valve is kept closed. A readjustment made on the basis of a measurement of the actually metered process liquid quantity is unnecessary in particular.

The intermediate container is according to a further feature of the invention with a Level detection equipped. For this purpose, for example, a float switch can be used in combination with a reed contact. In this case, the liquid level is detected at Prozesschemikalie within the intermediate container by means of the float switch. Once the maximum level height reached in the chamber of the intermediate container and the float switch is thus in its uppermost position, there is a reed contact circuit with the result that further compressed air supply to the compressed air line is omitted, a vacuum education in the intermediate container for Nachförderung of process chemical from the reservoir in the Intermediate container so no longer takes place. The level detection thus ensures that there can be no overfilling or even overflowing of the intermediate container. The maximum fill level is below the second port of the intermediate container and preferably also below the first port of the intermediate container. Once a predetermined minimum level reaches and the float switch is thus in its intended lowermost position, there is a reed contact circuit with the result that only a compressed air to the compressed air line is made before a subsequent dosing and thus a vacuum education in the intermediate container for Nachförderung of process chemical from the Reservoir is in the intermediate container. The minimum fill level is in particular above the third port of the intermediate container. This prevents the conveyed process liquid has air pockets, so that the dosing accuracy is increased.

In terms of the method, a method for metering a liquid process chemical from a storage container into a washing compartment of a program-controlled cleaning and / or disinfecting machine, in which a first step in one both with the storage container and with the washing compartment in fluidic Compound intermediate container generates a negative pressure and consequently process chemical is transferred from the reservoir into the intermediate container and in which in a second step in the intermediate container creates an overpressure and consequently located in the intermediate container process chemical is conveyed into the washing compartment. As described above, the program-controlled automatic cleaning and / or disinfecting machine has a storage container for storing process chemicals and an intermediate container in fluid communication with the storage container and also with the washing compartment, which has a Chamber for temporary storage of Prozesschemikalie includes. The vacuum generation in the intermediate container takes place by suction of air from this chamber, in which the process chemical is temporarily stored. As a result, process chemical is transferred from the reservoir to this chamber. In the second step, an overpressure is generated in the intermediate container by introducing compressed air into the chamber and consequently conveyed into the chamber located in the process chamber in the dishwasher.

This procedure provides the already vorerläuterten advantages. In particular, a basically wear-free operation is possible. In addition, there is no contact between the process chemical and the components used for compressed air generation and guidance.

Incidentally, the method according to the invention is characterized in that the fluidic connection between the intermediate container and the washing compartment is closed in order to generate negative pressure in the intermediate container. This happens in particular automatically by a non-return valve arranged there. A backflow of process chemical from the wash cabinet back into the intermediate container is thus prevented.

It is further provided according to a further feature of the invention that the fluidic connection between the reservoir and intermediate container is closed to generate overpressure in the intermediate container. This happens in particular automatically by a non-return valve arranged there. This ensures that process chemical already present in the intermediate container does not flow back into the storage container.

The embodiment of the invention is characterized in particular by the fact that, in contrast to previously known devices, the metering rate is increased, and this with simultaneously improved metering accuracy or process reliability. In addition, the reliability is increased, which allows longer maintenance intervals and provides an extended service life. Since the device according to the invention basically operates without contact, the chemical resistance to potentially aggressive process chemicals is also improved. In addition, a cost reduction is achieved, in particular due to the increased reliability and / or extended maintenance intervals.

Fig. 1

in schematisch perspektivischer Darstellung die erfindungsgemäße Vorrichtung gemäß einem ersten Verfahrensschritt und

Fig. 2

in schematisch perspektivischer Darstellung die erfindungsgemäße Vorrichtung gemäß einem zweiten Verfahrensschritt.

Further features and advantages of the invention will become apparent from the following description with reference to FIGS. Show

Fig. 1

in a schematic perspective view of the device according to the invention according to a first method step and

Fig. 2

in a schematic perspective view of the device according to the invention according to a second method step.

• Zur Eindosierung einer flüssigen Prozesschemikalie 2 aus einem Vorratsbehälter 4 in einen Spülraum 3 eines in den Figuren nicht näher dargestellten programmgesteuerten Reinigungs- und/oder Desinfektionsautomaten dient die erfindungsgemäße Vorrichtung 1. Diese verfügt über eine Druckluftleitung 10, die ausgehend von einer in den Figuren nicht dargestellten Druckluftquelle in den Spülraum 3 des Reinigungs- und/oder Desinfektionsautomaten einmündet. In diese Druckluftleitung 10 integriert sind im gezeigten Ausführungsbeispiel in Strömungsrichtung der Druckluft ein Druckluftventil 11, ein 2-2-Wegeventil 12, eine Vakuumdüse 13 sowie ein 2-2-Wegeventil 14.

The FIGS. 1 and 2 in each case show a schematic representation of the device according to the invention, wherein two different method steps are shown. The figures show as follows:

• For dosing a liquid process chemical 2 from a reservoir 4 in a washing compartment 3 of a program-controlled cleaning and / or disinfecting machine not shown in the figures, the device of the invention is 1. This has a compressed air line 10, which starting from a not shown in the figures Compressed air source discharges into the washing compartment 3 of the cleaning and / or disinfecting machine. Integrated in this compressed air line 10 in the illustrated embodiment in the flow direction of the compressed air, a compressed air valve 11, a 2-2-way valve 12, a vacuum nozzle 13 and a 2-2-way valve fourteenth

Via a line 15, an intermediate container 5 is connected to the vacuum nozzle 13. The intermediate container 5 is also connected via a metering 8 in fluid communication with the washing compartment 3. In the dosing 8 a check valve 9 is integrated. The metering line 8 opens between the vacuum nozzle 13 downstream directional control valve 14 and the Spülraumeinlass 22 in the compressed air line 10th

The reservoir 4 is connected via a line 6 in fluid communication with the intermediate container 5. In the line 6, a check valve 10 is integrated.

The operation of the device 1 according to the invention is as follows: In a first step, in Fig. 1 is shown, the compressed air line 10 is pressurized with compressed air pulses. The 2-2-way valves 12 and 14 are opened, so that the given on the compressed air line 10 pressure pulses in correspondence of the arrows 16, the compressed air line 10 flow through and reach the end of the compressed air line 10 into the washing compartment 3. The flow through the vacuum nozzle 13 has the result that in the connected to the vacuum nozzle 13 line 15, a negative pressure. This negative pressure is due to a "entrainment effect", which is caused by the pressure pulses delivered by the compressed air line 10.

The resulting in the line 15 negative pressure propagates in the intermediate container 5, where it also comes to the formation of a negative pressure. As a result of this pressure prevailing in the intermediate container, the check valve 7 opens, that is, the line 6 between the reservoir 2 and intermediate container 5 is opened. There is a pressure equalization, as a result process liquid 2 flows from the reservoir 4 in correspondence of the arrow 18 via the line 6 into the intermediate container 5. The check valve 9 of the line 8 is closed in the intermediate container 5 in the case of negative pressure training in the intermediate container 5 or in an influx of process chemical 2 from the reservoir 4.

The filling of the intermediate container 5 takes place until a magnet, which is associated with a float switch within the intermediate container 5, switches a reed contact. By this switching signal information is forwarded to a higher-level control that the intermediate container 5 is completely filled. The level of the process liquid 2 is at the maximum level below the first port 31, which connects the intermediate container 5 with the reservoir 4, and the second port 32, which connects the intermediate container 5 with the vacuum nozzle 13.

Based on the situation of the filled intermediate container 5 is now followed by a second process step, as in FIG. 2 is shown and according to which the dosing of stored in the intermediate container 5 process chemical 2 takes place in the washing compartment 3.

To introduce the process chemical 2 into the washing compartment 3, the second 2-2-way valve 14 is closed when the compressed air line 10 is pressurized with compressed air. The introduced into the compressed air line 10 compressed air can therefore no longer flow into the washing compartment 3. Instead, it flows via the vacuum nozzle 13 in accordance with the arrow 20 into the conduit 15 and thus into the intermediate container 5. The check valves 7 and 9 are closed at this time, so that it comes to the formation of an overpressure within the intermediate container. Upon reaching a predeterminable in its magnitude overpressure opens the check valve 9 of the line 8 and under the prevailing overpressure stored in the intermediate container 5 process chemical 2 can flow in accordance with the arrow 21 via the line 8 and the compressed air line 10 into the washing compartment 3. It takes place as a dosing of process chemical 2 in the washing compartment 3.

For the purpose of quantity monitoring, a device not shown in the figures can be provided, which is preferably integrated in the connecting line 8 between the intermediate container 5 and the washing compartment 3.

reference numeral

1

contraption

2

process chemical

3

Wash cabinet

4

reservoir

5

intermediate container

6

management

7

check valve

8th

dosing

9

check valve

10

Compressed air line

11

Pressure control valve

12

2-2-way valve

13

vacuum nozzle

14

2-2-way valve

15

management

16

arrow

17

arrow

18

arrow

19

arrow

20

arrow

21

arrow

22

Spülraumeinlass

30

chamber

31

First connection

32

Second connection

33

Third connection

Claims (13)

Apparatus for metering a liquid process chemical (2) from a storage container (4) into a washing compartment (3) of a program-controlled automatic washer-disinfector, with a compressed air line (10) opening into the washing compartment (3) of the machine and to the compressed-air line (10) connected intermediate container (5), which is equipped for a fluidic connection to the reservoir (4). Apparatus according to claim 1, characterized by a vacuum nozzle (13), is connected under the interposition of the intermediate container (5) to the compressed air line (10). Apparatus according to claim 1 or 2, characterized by a directional control valve (14), which is downstream of the vacuum nozzle (13). Device according to one of the preceding claims, characterized by a directional control valve (12), which is upstream of the vacuum nozzle (13) fluidically. Device according to one of the preceding claims, characterized in that the intermediate container (5) with the washing compartment (3) via a metering line (8) is fluidically connected, wherein the metering line (8) opens into the compressed air line (10). Device according to one of the preceding claims, characterized in that the intermediate container (5) has a fill level detection. Device according to one of the preceding claims, characterized in that the intermediate container (5) has three connections (31, 32, 33), namely a first connection (31) for the fluidic connection of the intermediate container (5) to the reservoir (4), a second Connection (32) for the fluidic connection of the intermediate container (5) to the compressed air line (10) and a third connection (33) for the fluidic connection of the intermediate container (5) to the washing compartment (3). Device according to the preceding claim, characterized in that the intermediate container (5) comprises a chamber (30) from which all three connections (31, 32, 33) extend. Device according to one of the two preceding claims, characterized in that the second terminal (32) of the intermediate container (5) is arranged above the intermediate container (5) than the third connection (33) of the intermediate container (5). Method for dosing a liquid process chemical (2) from a storage container (4) into a washing compartment (3) of a program-controlled automatic washer-disinfector comprising a storage container for storing process chemical (2) and one with the storage container (4) as well with the washing compartment (3) in fluidic connection intermediate container (5), which comprises a chamber (30) for Zwischenbefraatung the process chemical (2), wherein in a first step in the intermediate container (5) by suction of air from the chamber (30 ) generates a vacuum and as a result process chemical (2) from the reservoir (4) is transferred into the chamber (30) and in which in a second step in the intermediate container (5) by introducing compressed air into the chamber (30) generates an overpressure and as a result in the chamber (30) located process chemical (2) is conveyed into the washing compartment (3). A method according to claim 10, characterized in that in the vacuum generation in the intermediate container (5), the fluidic connection between the intermediate container (5) and the washing compartment (3) is closed. A method according to claim 10 or 11, characterized in that in the overpressure generation in the intermediate container (5), the fluidic connection between the reservoir (4) and intermediate container (5) is closed. Method according to one of Claims 10 to 12, characterized in that the level of the process chemical (2) which changes from the reservoir (4) during dosing of the process chemical (2) into the washing compartment (3) and when the process chemical (2) is refilled the chamber (30) of the intermediate container (5) always below the second port (32) of the intermediate container (5) and above the third port (33) of the intermediate container (5).

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