METHOD FOR PREVENTING MICROBIAL FARMING OF A CLEANING DEVICE FOR A DOSING SYSTEM AND CLEANING DEVICE

Description

[0001] The invention relates to a method for preventing microbial contamination of a cleaning device for a dosing system, wherein the cleaning device comprises at least one mechanical cleaning element with at least one cleaning surface. Furthermore, the invention relates to a method for cleaning a dosing system, a cleaning device, and a dosing system.

[0002] Dosing systems enable the precise delivery of a specific amount of a dispersion on demand. For the purposes of the present invention, dosing systems generally refer to all systems that enable the metered delivery of a material. Dosing systems are used in particular for mixing emulsion paints.

[0003] A dosing system for paints, for example, is described in DE 196 54 829 A1. A particular problem with dosing systems for dispersions is microbial contamination by fungi and bacteria. This is due to the dispersion(s) being stored in a corresponding container in the dosing system, sometimes for several weeks or months. The microbial contamination is not limited to the storage container in the dosing system, but spreads to all elements of the dosing system that come into contact with the contaminated dispersion, in particular to the dosing unit, by means of which the stored dispersion can be dispensed in a controlled amount. The dosing unit usually comprises a so-called pump head, via which the dispersion can be dispensed from the dosing system. Over time, the pump head and in particular its outlet opening or-nozzle with dispersion residues, so that regular, usually mechanical cleaning of this outlet opening is necessary. Cleaning devices are known for this purpose, which for example comprise a rotating brush, with the help of which the outlet opening is reliably cleaned. The rotating brush, in turn, is cleaned or rinsed in a cleaning bath in which it is partially immersed during cleaning operation. If the cleaning bath is not changed regularly, fungi and bacteria can form and contaminate the cleaning device. If the dosing system has a plurality of storage containers for dispersions with a corresponding plurality of pump heads, as is the case with paint mixing systems, for example, the microbial contamination of one stored dispersion can also spread to the other dispersions.This can be achieved by cleaning the contaminated dispersion residues from the outlet opening or nozzle of a pump head, which then collect in the cleaning bath. The microbial contamination is then distributed to the pump heads of the initially uncontaminated dispersions via the cleaning brush, which in turn is continuously rinsed in the cleaning bath.

[0004] JP H04 107824 A discloses a cleaning device for semiconductor wafers comprising a rolling brush, wherein the rolling brush is washed in a washing container with ozone water.

[0005] DE 102 48 561 A1 describes a milking device and a method for disinfecting milking components. The method is particularly suitable for disinfecting (rotating) cleaning brushes for udder cleaning.

[0006] DE 27 45 853 B1 describes a paint mixing device with a carousel-like storage rack with several paint containers, each provided with a controllable outlet valve, and a cleaning device.

[0007] EP 1 990 102 A1 describes a dispensing device with a cleaning device for cleaning a dispensing opening, wherein the cleaning device comprises a cleaning brush and a liquid reservoir with a cleaning liquid.

[0008] JP 2007 167837 A describes, according to the preamble of claim 1, a cleaning device for an outlet nozzle of a coating device, which comprises a rotating roller for receiving coating liquid emerging from the outlet nozzle.

[0009] The present invention is therefore based on the object of providing a method by means of which the microbial contamination of a cleaning device for a dosing system is effectively prevented.

[0010] A further object of the present invention is to provide a cleaning device for a dosing system, in particular for a dispersion, especially for a paint dosing system, in which microbial contamination of the cleaning device and the dosing system is effectively avoided.

[0011] Further tasks arise from the following explanations.

[0012] The above objects are achieved in a method according to the preamble of claim 1 in that the at least one cleaning surface of the at least one mechanical cleaning element is at least temporarily exposed to an oxidizing agent, wherein the oxidizing agent is a gaseous oxidizing fluid and wherein the oxidizing fluid contains ozone.

[0013] The particular advantage of the method according to the invention is that by applying an oxidizing agent to at least one mechanical cleaning element, the accumulation and subsequent proliferation of microbial contamination, such as bacteria, mold, or yeast, is effectively prevented over a long period of time. If microbial contamination has already occurred, the method according to the invention allows it to be reliably eliminated.

[0014] Surprisingly, it has been shown that with the method according to the invention for preventing microbial contamination of a cleaning device in a dosing system, specifically a paint dosing system, paint dispersions stored there can be protected from microbial contamination for months. This is because, as mentioned, the accumulation and subsequent proliferation of microbial contamination in the cleaning device itself is effectively prevented and, in connection with this, the spread of microbial contamination, if already existing, in the components to be cleaned with the cleaning device is also prevented. This is achieved according to the invention by consistently exposing the mechanical cleaning element(s) of the cleaning device to the oxidizing agent. A dispersion stored in the dosing system can be free of preservatives and nevertheless offers long-lasting protection against microbial contamination.Even with frequent use of the dosing system and repeated refilling of the container with fresh dispersion, protection against fungal and bacterial infestation is guaranteed by the method according to the invention if it is cleaned regularly.

[0015] The at least one cleaning surface of the at least one cleaning element of the cleaning device can be exposed to the cleaning agent continuously or discontinuously, for example, at periodic intervals (e.g., every 6, 12, or 24 hours). This depends, among other things, on the ambient conditions (temperature, humidity, etc.) in which the cleaning device is used and which may favor the development or proliferation of microbial contamination.

[0016] In principle, a wide variety of oxidizing agents are suitable for preventing or eliminating microbial infestation. Gaseous, liquid, or solid oxidizing agents are suitable. Liquid and solid oxidizing agents are preferably used as aqueous solutions, as this simplifies handling. According to the invention, the oxidizing agent is an oxidizing fluid. Furthermore, according to the invention, the oxidizing agent is a gaseous oxidizing fluid.

[0017] In order to achieve the most thorough and complete application of the at least one cleaning surface of the at least one cleaning element, an advantageous embodiment of the invention provides for the oxidizing agent to be sprayed or blown onto the at least one mechanical cleaning surface. Furthermore, it is preferred that the oxidizing agent be sprayed or blown onto the at least one mechanical cleaning surface essentially along its longitudinal extent, preferably over its entire surface. This ensures that there are no untreated surface sections where microbial contamination could begin.

[0018] A wide range of oxidizing agents is available in terms of chemical composition. Advantageously, the oxidizing agent is an oxygen- or chlorine-based oxidizing agent or a mixture thereof, preferably an oxygen-based oxidizing agent. The oxidizing agent is preferably selected from the group consisting of sodium hypochlorite, potassium hypochlorite, bleach, chlorine, ozone, hydrogen peroxide, peracetic acid, perborate, percarbonate, and mixtures thereof. These oxidizing agents are powerful oxidizing agents that effectively inhibit the growth of microbial organisms.

[0019] The oxidizing agent is particularly preferably selected from the group consisting of sodium hypochlorite, hydrogen peroxide, ozone, and mixtures thereof. The oxidizing agents from this group have proven particularly suitable for protecting the dispersion from microbial attack, as they are effective oxidizing agents. Furthermore, these oxidizing agents are essentially unproblematic for the dispersion, especially at the appropriately intended amounts. In particular, the aforementioned oxidizing agents do not cause any significant change in the color and / or quality of the dispersion at the appropriately intended amounts.

[0020] As mentioned, the use of an oxidizing fluid, i.e., a gaseous or liquid oxidizing agent, is preferred. According to the invention, a gaseous oxidizing agent is used. Furthermore, according to the invention, the oxidizing agent contains ozone. If the oxidizing agent contains ozone, or if ozone is used as the oxidizing agent, a particularly long-lasting antimicrobial effect is achieved. If the cleaning device is used in conjunction with a dosing system for dispersions, it proves to be advantageous that ozone is compatible with the common components of dispersions, in particular the common components of emulsion paints or pigment pastes. Furthermore, ozone can be very easily produced at the site of use.

[0021] Ozone can be produced, for example, from a chemical reaction of potassium permanganate with concentrated sulfuric acid or by electrolysis of dilute sulfuric acid, especially at low temperatures. Ozone can also be produced from air or oxygen under the influence of UV radiation.

[0022] According to a preferred embodiment of the method according to the invention, the ozone is generated in an ozone generator comprising a voltage source, in particular a high-voltage generator, and a discharge unit starting from air, in particular dried air, oxygen or an oxygen mixture with argon or carbon dioxide. The design of common ozone generators is known from the prior art. According to a common variant of ozone production, oxygen molecules are generated in a discharge unit, preferably by silent electrical discharge, so-called "Koronaentladung", dissociates into oxygen atoms, after which ozone synthesis and ozone enrichment occur in the plasma of the discharge filaments. The resulting ozone content of the final concentration of the gas mixture can be 1 to 5 wt.% with air as the starting gas and 6 to 13 wt.% with oxygen as the starting gas. Air is preferably used as the starting gas for ozone generation. Thus, when ozone is generated in a generator, ozone is produced cleanly from inexpensive starting materials.

[0023] According to a particularly advantageous embodiment of the invention, the at least one cleaning surface of the at least one mechanical cleaning element is cleaned at least temporarily in a cleaning bath during operation of the cleaning device, wherein the oxidizing agent optionally also acts on the cleaning bath at least temporarily.

[0024] In this embodiment of the cleaning device, the at least one cleaning surface of the at least one mechanical cleaning element is itself cleaned, so that the microbial contaminants adhering to the at least one cleaning surface are washed off the cleaning surface. This allows the cleaning device to operate completely autonomously over an extended period of time. Since the microbial contamination thus passes from the cleaning surface into the cleaning bath, it may be advisable to at least temporarily expose the cleaning bath itself to the oxidizing agent, in addition to the cleaning surface. In this case, the microbial contamination can be combated even more effectively, since residues of microbial contamination in the cleaning bath are combated directly.

[0025] According to a further advantageous embodiment of the invention, the oxidizing agent is sprayed or blown onto the at least one cleaning surface of the at least one mechanical cleaning element outside the cleaning bath. This allows the oxidizing agent to be directed even more precisely onto the at least one cleaning surface.

[0026] According to the invention, the mechanical cleaning element of the cleaning device has at least one cleaning surface. This can be designed in different ways. A circumferential cleaning surface is preferred, particularly with a cylindrical design of the mechanical cleaning element. It is understood that instead of a cylindrical design with a circular base, elliptical or polygonal bases are also possible. Instead of a circumferential cleaning surface, several non-connected cleaning surfaces are also possible, for example, a plurality of substantially flat cleaning surfaces, which can be arranged, for example, pointing radially outward and rotating about a common axis.

[0027] When designing the at least one cleaning surface, it should be noted that, in principle, all mechanical cleaning techniques are applicable within the scope of the present invention, such as wiping, scrubbing, sanding, etc. Depending on the particular cleaning technique selected, the cleaning surface is designed accordingly, for example, as a brush or sponge. According to an advantageous embodiment of the invention, the at least one cleaning element is designed as a brush, and its cleaning surface is accordingly designed as a brush surface. A cylindrical or roller-shaped brush is particularly preferred.Regardless of the geometric design of the brush surface, the oxidizing agent is preferably sprayed or blown into the brush essentially parallel to the bristles so that the bristles can be cleaned of microbial contamination along their entire length, resulting in a particularly thorough cleaning result.

[0028] If the at least one mechanical cleaning element is designed as a cylindrical or roller-shaped rotating brush and a cleaning bath is also used for the cleaning element, the brush can be partially immersed in the bath during operation of the cleaning device, with the result that the brush itself is constantly cleaned or rinsed in the cleaning bath during cleaning, which enables a high degree of automation.

[0029] With regard to the structural design of the oxidizing agent supply, a preferred solution is that the oxidizing agent is supplied via at least one supply line, wherein the at least one supply line is arranged substantially along the longitudinal extent of the at least one cleaning surface of the at least one mechanical cleaning element. The at least one supply line further comprises one, preferably a plurality of, outlet openings aligned with the at least one cleaning surface for spraying or blowing on the oxidizing agent. This structural solution is characterized by a simple and quickly implemented design and enables the at least one cleaning surface of the at least one mechanical cleaning element to be exposed to the oxidizing agent over as much of its entire surface as possible.This design solution is particularly suitable for the use of cylindrical or roller-shaped mechanical cleaning elements, such as cylindrical or roller-shaped sponges or brushes.

[0030] A further aspect of the present invention relates to a method for cleaning a dosing system, in particular for a dispersion, especially a paint dosing system, wherein the dosing system has at least one dosing unit with a pump head, wherein the pump head is cleaned by means of a cleaning device with at least one mechanical cleaning element having at least one cleaning surface, wherein microbial contamination of the cleaning device is avoided with a method according to one of claims 1 to 11.

[0031] The advantages explained above apply accordingly to the advantages of this cleaning method. The advantages are particularly evident when the cleaning method is used in a paint dosing system with multiple dosing units, since the method according to the invention can effectively prevent the spread of microbial contamination from one dosing unit to several or all other dosing units, which has always been a particular problem in cleaning methods known in practice.

[0032] In terms of the device, the object stated at the outset is achieved with a cleaning device for a dosing system, in particular for a dispersion, specifically for a paint dosing system, comprising at least one mechanical cleaning element with at least one cleaning surface and a supply unit for an oxidizing agent for at least temporarily applying an oxidizing agent to the at least one cleaning surface, wherein the cleaning device is configured for cleaning the dosing system according to claim 12.

[0033] Again, the above statements apply accordingly to the advantages of the device according to the invention.

[0034] According to an advantageous embodiment of the cleaning device, the cleaning device comprises a cleaning bath for at least temporarily cleaning the at least one cleaning surface of the at least one mechanical cleaning element during operation of the cleaning device.

[0035] A further aspect of the present invention relates to a dosing system for a dispersion, in particular a paint dosing system, comprising a cleaning device according to claim 13 or 14.

[0036] In addition to the cleaning device according to the invention, which can be subjected to oxidizing agents, the dosing system according to the invention can also comprise devices for preventing microbial contamination of other parts of the dosing system, in particular of the dispersion(s) contained in the container(s). In particular, the dosing system can comprise a device with which an oxidizing agent, such as ozone, is introduced into one or more of the containers in which the dispersion is stored, as described in the international patent application PCT / EP2019 / 052537 (see in particular Fig. 1 and the corresponding figure description of PCT / EP2019 / 052537). The introduction of oxidizing agents, in particular ozone, into the container(s) of the dosing system can be carried out, for example, with the aid of suitable adapters, as described in the international patent application PCT / EP2019 / 052537 (cf. in particular Fig. 3 , 5, 6, 7a, 7b, 8a and 8b as well as the associated figure descriptions of PCT / EP2019 / 052537). In this context, the disclosure in the international patent application PCT / EP2019 / 052537 is expressly incorporated by reference. At least temporary exposure of the cleaning surface of the at least one mechanical cleaning element of the cleaning device, as described herein, combined with the introduction of oxidizing agent into one or more of the containers in which the dispersion is stored, as described in PCT / EP2019 / 052537, represents a particularly preferred embodiment of the present invention.

[0037] The present invention is explained below with reference to a drawing illustrating an embodiment of the invention. The drawings show: Fig. 1A a dosing system for an emulsion paint with a cleaning device in a schematic plan view, Fig. 1B the dosing system of the Fig. 1A in schematic side view, Fig. 2 the cleaning device of the dosing system of the Fig. 1 in perspective view, Fig. 3 the cleaning device of the Fig. 2 in cross-section according to section line III-III from Fig. 2 , Fig. 4A the supply of an oxidizing agent to the cleaning device of the Fig. 2 in an enlarged perspective view and Fig. 4B the supply of an oxidizing agent to the cleaning device of the Fig. 2 in to Fig. 4A rotated perspective view.

[0038] Fig. 1 shows a preferred embodiment of a dosing system for mixing emulsion paint with a cleaning device in a schematic top view. It is understood that, in principle, the same setup can also be used for dosing and / or mixing other materials.

[0039] The dosing system of the Fig. 1 In detail, it comprises a plurality of containers 1 arranged in a carousel-like manner on a plate X4 shown in a dot-dash line, each container 1 being connected to a dosing unit X1 via a supply line. The drive of the plate X4 is connected to a control computer 12 via a control line L1. Furthermore, the dosing units X1 are each connected to the control computer via control lines L11. As shown in the top view of the Fig. 1 As can be seen, the dosing unit X1 of one of the ink containers 1 is arranged above a receiving container, in this case a bucket 9, so that the dispersion stored in this container 1 can be dosed into the bucket 9 via the associated dosing unit X1. The bucket 9, in turn, stands on a scale 10, which is connected to the control computer 12 via a control line L2. The control computer 12, in turn, is connected to a label printer 13 via a control line L3.

[0040] The dosing unit X1, which is positioned clockwise X5 relative to the dosing unit X1 positioned above the bucket 9, is positioned above a cleaning device X2 in such a way that the Fig. 1B bis 4B The cleaning device X2, which will be described in detail, cleans the pump head X6 (see Fig. 1B ) of the dosing unit X1. As will be explained in more detail below, the cleaning device X2 comprises a mechanical cleaning element in the form of a rotating cylindrical brush X29 with a cylindrical cleaning surface X31 designed as a brush surface, by means of which the pump head X6 of each dosing unit X1 can be cleaned of paint residues.

[0041] As in Fig. 1A Also shown schematically, the cleaning device X2 is connected via a supply line to an ozone generator 3, into which air or oxygen is introduced via a diaphragm pump 14. In the ozone generator 3, ozone is generated, for example, by means of a corona discharge, which is fed via the supply line X24 (in Fig. 1A only shown schematically) into the cleaning device X2 in order to act on the rotating brush X29.

[0042] During operation of the dosing system, the control computer 12 calculates the proportions of the primary colors stored in the containers 1 after the customer has entered a desired color and the desired volume. It then controls the drive of the plate X4 such that the dosing units X1 of the containers 1 containing the required primary colors are positioned one after the other over the bucket 9, and the calculated amount is dispensed into the bucket 9 to obtain the desired color in the bucket 9. This is monitored by the scale 10 connected to the control computer via line L2. The drive of the plate X4 is controlled such that it always rotates clockwise X5. This results in the pump head X6 of each dosing unit X1 involved in the color mixing process being cleaned by the cleaning device X2 immediately after use, thus removing any dispersion residue. The appropriate label for the color mixture is printed via the label printer 13.

[0043] Fig. 2 and 3 show the cleaning device X2 of the dosing system of the Fig. 1 in perspective view and in cross-section according to section line III-III from Fig. 2 .

[0044] According to Fig. 3 The cleaning device X2 comprises as its central element a brush X31 rotating clockwise X32 in the present view, which, in operation, cleans the pump head X6 of dispersion residues with the bristles of the brush surface X31 arranged on the upper side, while the bristles of the brush X29, which are immersed in a cleaning bath X34, are freed from the paint residues in the cleaning bath X34. The cleaning bath X34 is formed in the present case by a water bath which is located in a container X33. As shown in particular in Fig. 2 As can be seen, a gas stream containing ozone is fed via the supply line X24 as an oxidising agent through a plurality of outlet openings X28 arranged in an outlet region X26 of the supply line (cf. Fig. 4B ) is blown onto the brush X29, with the gas stream being blown into the brush essentially parallel to the bristles of the brush surface X31, i.e., essentially radially. The container X33 of the cleaning bath X34 is connected to a housing X21 via a mounting profile X22.

[0045] The mounting rail X22 including the supply line X24 for the ozone-containing gas stream is in the Fig. 4A and 4B shown again in two perspective views, whereby in the representation of the Fig. 4B the outlet openings X28 for the gas flow are clearly visible in the outlet area X26 of the supply line X24, which is aligned parallel to the axis of the brush X29.

[0046] The particular advantage of the cleaning device and the cleaning method is that there is no risk of microbial contamination with bacteria and fungi in either the cleaning bath X34 or the brush X29, as this is effectively prevented by the injected ozone as an oxidizing agent. Accordingly, the method according to the invention proves to be extremely effective in preventing microbial contamination of the cleaning device X2. Furthermore, the risk of contamination of other pump heads X6 by the cleaning device X2 is minimized, even if the cleaning device X2 cleans a microbially contaminated pump head X6—and thus corresponding contaminants collect on the cylindrical brush surface X31 and in the cleaning bath X34—and subsequently, further pump heads X6 are cleaned.

Claims

1. Method for preventing the microbial attack of a cleaning device (X2) for a dosing system, the cleaning device (X2) comprising at least one mechanical cleaning element (X29) which has at least one cleaning surface (X31), characterized in that the at least one cleaning surface (X31) of the at least one mechanical cleaning element (X29) is at least temporarily exposed to an oxidizing agent, the oxidizing agent being a gaseous oxidizing fluid and the oxidizing fluid containing ozone.

2. Method according to claim 1, characterized in that the oxidizing agent is blown onto the at least one mechanical cleaning surface (X31).

3. Method according to claim 2, characterized in that the oxidizing agent is blown onto the at least one cleaning surface (X31) substantially along its longitudinal extent, preferably over the entire surface thereof.

4. Method according to any of claims 1 to 3, characterized in that the at least one cleaning surface (X31) of the at least one mechanical cleaning element (X29) is cleaned at least temporarily in a cleaning bath (X34) during operation of the cleaning device (X2), optionally the cleaning bath (X34) also being at least temporarily exposed to the oxidizing agent.

5. Method according to claim 4, characterized in that the oxidizing agent is blown onto the at least one mechanical cleaning surface (X31) and the blowing of the oxidizing agent onto the at least one cleaning surface (X31) of the at least one mechanical cleaning element (X29) takes place outside the cleaning bath (X34).

6. Method according to any of claims 1 to 5, characterized in that the at least one mechanical cleaning element (X2) has a circumferential cleaning surface (X31).

7. Method according to any of claims 1 to 6, characterized in that the at least one mechanical cleaning element (X29) is cylindrical or roller-shaped.

8. Method according to any of claims 1 to 7, characterized in that the at least one mechanical cleaning element (X29) comprises at least one brush.

9. Method according to claim 8, characterized in that the at least one mechanical cleaning element (X29) is designed as a rotating cylindrical brush.

10. Method according to claim 8 or 9, characterized in that the oxidizing agent is blown into the brush substantially in parallel with the bristles.

11. Method according to any of claims 1 to 10, characterized in that the oxidizing agent is supplied via at least one supply line (X24, X26), the at least one supply line (X24, X26) being arranged substantially along the longitudinal extent of the at least one cleaning surface (X31) of the at least one mechanical cleaning element (X29), the at least one supply line (X24, X26) having one, preferably a plurality of outlet openings (X28) aligned with the at least one cleaning surface (X31) for blowing the oxidizing agent.

12. Method for cleaning a dosing system, in particular for a dispersion, especially a paint dosing system, the dosing system comprising at least one dosing unit (X1) having a pump head (X6), the pump head (X6) being cleaned by means of a cleaning device (X2) which comprises at least one mechanical cleaning element (X29) having at least one cleaning surface (X31), characterized in that a microbial attack of the cleaning device (X2) is prevented by a method according to any of claims 1 to 11.

13. Cleaning device (X2) for a dosing system, in particular for a dispersion, especially for a paint dosing system, comprising at least one mechanical cleaning element (X29) having at least one cleaning surface (X31) and comprising a supply unit (X24, X26) for an oxidizing agent for at least temporarily applying an oxidizing agent to the at least one cleaning surface (X31), wherein the cleaning device (X2) is configured to clean the dosing system according to claim 12.

14. Cleaning device according to claim 13, characterized in that the cleaning device (X2) comprises a cleaning bath (X34) for at least temporarily cleaning the at least one cleaning surface (X31) of the at least one mechanical cleaning element (X29) during operation of the cleaning device (X2).

15. Dosing system for a dispersion, in particular a paint dosing system, comprising a cleaning device (X2) according to claim 13 or 14.