Patent Application
20150282690
The invention relates to a cleaning device and to a cleaning method performed using a cleaning device, in particular for cleaning, sterilizing or disinfecting dishes, working equipment, foodstuffs or the like, the cleaning device comprising a liquid cycle, wherein a cleaning liquid can circulate in the liquid cycle, wherein items to be cleaned can be exposed to the cleaning liquid within the liquid cycle, the cleaning device comprising an electrolytic device having a diamond electrode for producing an oxidizing agent, the cleaning device having a feed line that is connected to the liquid cycle.
Devices and methods of the aforementioned kind are sufficiently known and are used and implemented in dish washers and similar cleaning devices, for example. Moreover, they can also be used for cleaning or disinfecting medical equipment, foodstuffs, such as fruits and vegetables, workpieces or the like. The known cleaning devices commonly comprise a liquid cycle, in which a cleaning liquid is circulated with the aid of a pump. In a section of the liquid cycle, the items to be cleaned can be exposed to the cleaning liquid, for example by spraying the items with the cleaning liquid, so as to remove any pollutants that may be sticking to the item. The cleaning liquid is thus loaded with pollutants by repeatedly circulating in the liquid cycle. In particular in a dish washer these are mainly organic pollutants. Dish washers or also other similar cleaning devices use tap water together with a detergent additive as a cleaning liquid, the items to be cleaned being sprayed with the cleaning liquid until pollutants on a surface of the items have been removed because of a mechanical and chemical removal process. Subsequently, the polluted cleaning liquid is pumped off, wherein the liquid cycle can be rinsed with tap water. The tap water or fresh water is fed into the liquid cycle via a feed line. After the rinse, a cleaning process or cleaning cycle is usually complete. In a cleaning process of this kind, a sterilizing or disinfecting effect substantially depends on the cleaning agents used and on the temperatures of the liquids. The aim is to achieve a cleaning that is as cost-effective and environmentally friendly as possible through a reduced use of cleaning agents and cleaning liquids or tap water.
From AT 502499 B1, a cleaning device and a method are known in which an electrolytic device having a diamond electrode or an electrode pair is arranged in the liquid cycle. The cleaning liquid circulating in the liquid cycle flows past the electrodes, the diamond electrodes being supplied with electric current, which causes OH radicals to be produced in the cleaning liquid. Owing to their reactivity and oxidizing power, the OH radicals lead to an improved cleaning of the items with a simultaneously cytocidal effect on microorganisms and the like. With regard to the structure and function of an electrolytic device of this kind and its chemical cause-effect relationships, reference is made to AT 502499 B1.
The use of a diamond electrode is disadvantageous in that a lifespan of the diamond electrodes is substantially shortened if the diamond electrodes come into contact with an acidic medium, such as acetic acid in a liquid cycle of a dish washer. Moreover, the removal of pollutants from the items to be cleaned loads the cleaning liquid with undefined substances, which may be electrochemically synthesized in the electrolytic device. This can lead to the production of undesired substances that could damage the items to be cleaned or the environment. Nevertheless, it is necessary for the diamond electrode to be in contact with the cleaning liquid for as long as possible so as to produce a large amount of the oxidizing agent.
Hence, it is the object of the present invention to propose a cleaning device and a cleaning method in which a lifespan of a diamond electrode is prolonged.
This object is attained by a device having the features of claim 1 and by a method having the features of claim 9.
The cleaning device according to the invention, in particular for cleaning, sterilizing or disinfecting dishes, working equipment, foodstuffs or the like, comprises a liquid cycle, wherein a cleaning liquid can circulate in the liquid cycle, wherein items to be cleaned can be exposed to the cleaning liquid within the liquid cycle, the cleaning device comprising an electrolytic device having a diamond electrode for producing an oxidizing agent, the cleaning device comprising a feed line that is connected to the liquid cycle, wherein the electrolytic device is connected to the feed line in such a manner that the oxidizing agent can be introduced into the liquid cycle via the feed line.
The cleaning liquid supplied to the cleaning device, i.e. to the liquid cycle, can preferably be continuously circulated within the liquid cycle. The cleaning liquid in the liquid cycle does not immediately come into contact with the electrolytic device, i.e. with the diamond electrode, a contact of pollutants or acid components possibly present in the cleaning liquid with the diamond electrode thus being avoided. In this manner, it is also possible to safely preclude a synthesis of undesired substances due to electrolysis. Since the electrolytic device is connected to the feed line, the oxidizing agent produced by the electrolytic device can also be supplied to the liquid cycle as fresh water via the feed line. At the beginning of a cleaning cycle, the liquid cycle is still being supplied or replenished with unpolluted cleaning liquid, wherein said cleaning liquid can be dosed with the oxidizing agent even prior to its introduction into the liquid cycle. It is also possible to supply fresh cleaning liquid during a cleaning cycle via the feed line, wherein said cleaning liquid can contain the oxidizing agent. It has proven unnecessary to subject a total amount of cleaning liquid present in the liquid cycle to electrolytic treatment in order to obtain a sufficient amount of oxidizing agent that is required for a desired cleaning result. In fact, it is sufficient to electrolytically treat or add oxidizing agent to only a part of the cleaning liquid present in the liquid cycle
Preferably, a circulator pump and a cleaning chamber for receiving and for spraying items to be cleaned can be arranged in the liquid cycle. The cleaning device can then be integrated in a dish washer or the like, for example. In that case, the liquid cycle is a system that is closed off from its environment. Independently thereof, however, the cleaning chamber can also be open towards its environment, for example in the manner of a chamber through which the items to be cleaned can be continuously conveyed. With the aid of the circulator pump, it is possible to spray the items to be cleaned with cleaning liquid and to subsequently collect the cleaning liquid to use it repeatedly. Tap water with an added detergent or cleaning agent can be used as a cleaning liquid. The cleaning agent can then cause a removal of pollutants from the items to be cleaned due to a chemical removal process. In principle, the oxidizing agent can be added to the cleaning liquid at any point during a cleaning cycle. A large amount of tap water can be saved in particular by the repeated use of the cleaning liquid and its circulation in the liquid cycle.
It is particularly advantageous if an admixing device of the cleaning device is arranged in the liquid cycle, wherein the oxidizing agent can then be admixed to the cleaning liquid present in the liquid cycle via the admixing device. In this regard, it is immaterial whether the cleaning liquid present in the liquid cycle already contains an oxidizing agent. A desired cleaning result can be achieved even at a small amount of oxidizing agent in the liquid cycle. However, the oxidizing agent can be consumed by a reaction with other substances during circulation in the liquid cycle so that it may be useful to maintain a concentration of the oxidizing agent by admixing. Furthermore, the admixing device can have a check valve that makes sure that polluted cleaning agent cannot flow from the liquid cycle into the feed line. In this manner, it can be ensured that only unpolluted cleaning agent or also fresh water can enter the liquid cycle via the feed line.
The admixing device can comprise a jet pump within the liquid cycle. Since a circulation of the cleaning liquid in the liquid cycle forms a flow anyway in the liquid cycle, which is formed by liquid conduits at least in sections, cleaning liquid can be suctioned from the feed line by means of the jet pump and be admixed to the liquid cycle. The jet pump can be realized in the manner of a water jet pump that causes a particularly thorough mixing of the cleaning liquid present in the liquid cycle and the freshly added cleaning liquid from the feed line. Besides, the use of a jet pump can also promote a reaction of the oxidizing agent with substances or pollutants present in the cleaning liquid.
In one embodiment, the admixing device can comprise a buffer tank in the feed line. The buffer tank can contain fresh cleaning liquid that is loaded with the oxidizing agent. The fresh cleaning liquid can then be continuously added to the cleaning liquid present in the liquid cycle or also at intervals, i.e. at certain points of the cleaning cycle. The use of a buffer tank or of a buffer reservoir allows the electrolytic device to be operated continuously and setting a desired concentration of the oxidizing agent in the later added fresh cleaning liquid. Cleaning liquid including an oxidizing agent can also be stored in the buffer tank so that after a cleaning cycle, fresh unpolluted cleaning liquid with the oxidizing agent is available for a subsequent cleaning cycle without first having to be produced in a drawn-out electrolytic process.
The cleaning device can also have a dosing device for an electrolyte, wherein the dosing device can be connected to the electrolytic device and/or to the feed line in such a manner that the electrolyte can be introduced into the electrolytic device. The electrolyte can in particular be a salt that serves as a cation source for electrolysis and is mixed with tap water that is supplied via the feed line. The dosing device can dose the salt as required directly into the feed line or, initially independently of the feed line, provide brine that is then dosed into the feed line. Alternatively, the dosing device can dose the salt or the brine directly into the electrolytic device. For handling the brine, the dosing device can have a mixing chamber and, if needed, a buffer reservoir.
It is particularly advantageous if the electrolytic device is arranged in a shared housing with the admixing device, the circulator pump and/or the dosing device, wherein the housing can then be connected to the liquid cycle. For example, the housing can be made of an injection-molded plastic material or also of another suitable material. The liquid cycle can then be guided directly through the housing, wherein the feed line can then also be connected to the housing. In particular if the electrolytic device is arranged in the housing together with another structural component of the cleaning device, such as the admixing device, the circulator pump and/or the dosing device, maintenance and repair as well as assembly of the cleaning device is significantly simplified. In case of a defect of one of the structural components, the housing then has to simply be separated from the liquid cycle and from the feed line and be replaced if needed. Also, shared control devices for the aforementioned structural components can then be arranged in the housing, which can then also have a shared power supply.
For an anode or cathode, the electrolytic device can have a diamond electrode and/or a pyrolytically coated graphite electrode and/or a stainless steel electrode. Thus, a pair of diamond electrodes can be provided, wherein a diamond electrode can also be combined with a pyrolytically coated graphite electrode. By using the pyrolytically coated graphite electrode, an even further prolonged lifespan of the electrolytic device and of the electrode can be achieved. Furthermore, in case of a defect of the diamond electrode or of the graphite electrode, only carbon comes into contact with the items to be cleaned.
The afore-described cleaning device can be integrated into a dish washer.
The cleaning method according to the invention is implemented using a cleaning device, in particular for cleaning, sterilizing or disinfecting dishes, working equipment, foodstuffs or the like, a cleaning liquid being circulated in a liquid cycle of the cleaning device, wherein items to be cleaned can be exposed to the cleaning liquid within the liquid cycle, an oxidizing agent being produced by means of an electrolytic device having a diamond electrode of the cleaning device, the cleaning device having a feed line that is connected to the liquid cycle, wherein the electrolytic device is connected to the feed line, the oxidizing agent being introduced into the liquid cycle via the feed line. With regard to the advantageous effects related to the method according to the invention, reference is made to the description of the advantages of the device according to the invention.
The oxidizing agent can be admixed to the cleaning liquid in the liquid cycle.
Furthermore, the electrolytic device can be supplied with fresh water or tap water and/or brine. Thus, the electrolytic device does not have to be arranged directly in the feed line. Instead, the electrolytic device can also be arranged in such a manner that the oxidizing agent produced by means of the electrolytic device is introduced into the feed line. If the electrolytic device is arranged directly at the feed line, the electrolytic device can be rinsed with the fresh water because then said fresh water can flow through the electrolytic device.
Furthermore, it may be provided that electric current is conducted via the diamond electrode only towards the end of a cleaning cycle. In this context, a cleaning cycle is a period of time that is required for a complete cleaning of the items to be cleaned. The cleaning cycle can comprise multiple cleaning steps at a repeated change of cleaning liquids. If required, it may also be provided that the oxidizing agent is produced towards the end of the cleaning cycle by supplying electric current to the diamond electrode, i.e. to the electrolytic device. Since sterilization or disinfection of the items to be cleaned can be achieved with the oxidizing agent, this sterilization or disinfection can be advantageously performed in the last cleaning step once the substantial pollutions have been removed from the item. For instance, tap water that is used for rinsing the liquid cycle of the items to be cleaned can be loaded with the oxidizing agent.
Furthermore, it may be provided that ozone is produced by means of the electrolytic device. Ozone (O3) is a relatively strong oxidizing agent, which can also irritate the airways in humans. If the ozone is added in a dosed manner in a closed liquid cycle and if it is largely depleted during a cleaning cycle, however, an adverse effect of this kind can be avoided while particularly good cleaning results can be achieved. Also, in this case, an additional loading of fresh water with NaCl is unnecessary.
It may also be provided that free chlorine or chlorine oxide is produced by means of the electrolytic device. This can take place in addition to the production of ozone or as an individual process. The free chlorine or chlorine oxide can be produced in the form of hypochlorous acid as an oxidizing agent. In particular if fresh water is loaded with NaCl, NaClO can be produced from a solution of this kind. By means of a corresponding control of the electrolytic device, the production of ozone can also be prevented if doing so is advantageous.
In a sump of the liquid cycle, cleaning liquid can be stored for a cleaning cycle that follows after an undefined period of time. The sump can be arranged within or below a cleaning chamber for collecting residual cleaning liquid in the cleaning cycle. To save cleaning liquid and fresh water, it may be provided in the cleaning method that not all the cleaning liquid in the liquid cycle, which is possibly spent, is pumped off and disposed of after the last cleaning step of a cleaning cycle. This is a regular process in dish washers, for example, so as to avoid that potential pollutants, such as food scraps, remain in the sump for a longer period of time. Under certain circumstances, this might lead to an undesired unpleasant smell. If the cleaning liquid is now loaded with an oxidizing agent, the cleaning liquid located in the liquid cycle can be successfully sterilized. The cleaning liquid that is present in the liquid cycle after the last cleaning step can then be at least partially stored or saved in the sump for a cleaning cycle that follows after an undefined period of time. Then, it is no longer necessary to use fresh water in particular for a pre-cleaning of items to be cleaned, which may allow saving an enormous amount of water.
Advantageous embodiments of the method become apparent from the dependent claims back-referenced to device claim 1.
In the following description, the invention is explained in more detail with reference to the accompanying drawings.
In the figures:
The cleaning device 10 further comprises a feed line 21 that is formed by conduit sections 22, 23 and 24 and is connected to a fresh water supply or to a tap water connection (not illustrated). An electrolytic device 25 of the cleaning device 10 is connected to the feed line 21. The electrolytic device 25 is integrated or arranged in particular between conduit sections 22 and 23 in the feed line 21. The electrolytic device 25 is substantially composed of an electrode chamber 26 and an electrode pair 27 of diamond electrodes 28 and a power supply connection 29 for the diamond electrodes 28. Tap water (not illustrated) can flow through the electrode chamber 26 comprising the diamond electrodes 28.
Furthermore, a dosing device 30 of the cleaning device 10 is provided, said dosing device 31 being connected to conduit sections 23 and 24 via a conduit section 31. The dosing device 30 has a dosing tank 32 in which a salt or brine (not illustrated) can be stored. With conduit section 31, a valve 33 is arranged via which the salt or the brine can be admixed as an electrolyte to the tap water flowing in from conduit section 24. A fresh water supply can be controlled in a mechanized manner via a valve 34 in conduit section 24.
By means of the electrolytic device 25, an oxidizing agent, such as ozone, can now be generated from the tap water loaded with the electrolyte in the electrode chamber 26 by means of the diamond electrodes 28. In conduit section 22, a valve 35 is arranged via which the tap water with the oxidizing agent can be introduced in a dosed manner into the liquid cycle 11. Conduit section 22 ends in the liquid cycle 11 between conduit section 13 and 14 in such a manner that the tap water with the oxidizing agent can be admixed to the cleaning liquid 17 in the liquid cycle 11 without allowing the cleaning liquid 17 to flow into the feed line 21. In this manner, a contact between the diamond electrodes 28 and the cleaning liquid 17 from the liquid cycle 11, which may oftentimes carry pollutants, is effectively prevented.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2014 206 275.6 | Apr 2014 | DE | national |
