WO1998050175A1

WO1998050175A1 - Method for cleaning and/or sterilizing surfaces

Info

Publication number: WO1998050175A1
Application number: PCT/DE1998/001242
Authority: WO
Inventors: Udo Krohmann; Bernd Neumann; Torsten Neumann
Original assignee: Udo Krohmann; Bernd Neumann; Torsten Neumann
Priority date: 1997-05-05
Filing date: 1998-04-30
Publication date: 1998-11-12
Also published as: DE19720159A1

Abstract

The invention relates to a method for cleaning the surface of bodies with a low dielectric loss factor (tan δ), such as objects or containers made from glass, ceramics or certain plastics and ridding said surface of impurities such as dirt, impregnations, adhering micro-organisms or the like. The method can simultaneously kill micro-organisms. The heating of bodies and fluids with high frequency radiation (dielectric heating) is a well-known method. The effect of the high-frequency electrical field depends upon the respective dielectric properties of said bodies. The use of said process for cleaning purposes was not previously known. The bodies which are to be cleaned (with a low dielectric loss factor or unpolarized material) are subjected to a defined amount of cleaning fluid (with a high dielectric loss factor or polarized material) and radiated with microwaves, wherein the amount of fluid, energy and duration is coordinated in such a way that the adhering impurities and the applied fluid are heated while avoiding the prolonged effect of heating upon said bodies.

Description

Methods for cleaning and / or sterilizing surfaces

The invention relates to a method for cleaning the surface of bodies with a low dielectric loss factor (tan δ), such as objects or containers made of glass, ceramics or some plastics, from contaminants such as dirt, microorganisms adhering to adhesives, etc. consist. The process can simultaneously kill microorganisms.

Hot water with chemical additives such as alkalis, detergents or other solvent substances are mainly used to clean various bodies and surfaces. The effect can be enhanced by pre-soaking, rinsing or mechanical brushing. Examples of this are dishwashers, car wash stations or bottle washing devices.

These procedures require large amounts of warm water. Some of the heat is also transferred to the objects to be cleaned, which results in a large energy consumption. A long exposure or soaking time is also necessary, which limits the throughput. Finally, careful rinsing is necessary to achieve hygienic surfaces.

Mechanical devices require drive and transmission elements that are prone to failure and are subject to wear.

Steam jet devices for cleaning are also known. Here the water requirement is reduced, but a higher temperature is required. The steam condenses on the bodies and thus also transfers a lot of energy to them.

According to DE OS 4326601, after cleaning bottles with lye and hot water spraying, they are additionally sprayed with steam white water several times. This results in a higher temperature and thus better germ killing. However, the expenditure on machine technology and energy is very large.

In DE OS 1497779 it was proposed to simultaneously act on the surface with a water jet with ultrasound in order to improve the detachment of dirt. For this purpose, a laser beam should be aimed at the point of impact of the water jet. In practice, this method has not yet become established.

From DE OS 4315318 it is known to apply heat locally to labels on glass containers. This is done by contact with a heating device. The heating softens the adhesive so that the label can be removed. The targeted exposure to heat is effective, but local, it only serves to remove labels.

Overall, the processes require a lot of water, energy and a high level of mechanical engineering and pollute the environment due to the cleaning agents used. In general, the heating of bodies and liquids by high-frequency radiation (dielectric heating) is known. The effect of the high-frequency electric field is dependent on the respective dielectric properties of the body. An application in this regard for cleaning is not yet known

The object of the invention is therefore to concentrate the heating on the area of the impurities and to achieve a dirt-removing effect without prolonged soaking or direct mechanical processing, and to kill microorganisms

According to the invention the object is achieved in accordance with the features of claim 1. Further special configurations of the method steps are set out in the subclaims

The invention is based on the knowledge that the swelling and dissolution rate increases with increasing temperature of the solvent and that vapor bubbles have a great mechanical effect

A microwave can be used to heat a liquid to boiling temperature in a very short time.This also applies to microorganisms that, like all living things, contain approx. 70% water. With microwave radiation, the liquid applied, including the impurities adhering to the body, is heated for a short time Due to the high liquid temperature that arises in the area of the contamination, this is dissolved or detached and microorganisms are killed. This is a prerequisite for the quickest possible attachment and detachment of contaminants their effects also cause a detachment of the contaminants. In order to maintain the effect until all the contaminants have been removed, a sufficient amount of liquid has to be added

Soiled and detached soiling / adhesions can then be removed using known methods

There is no major heating of the body with a small dielectric loss factor (glass, ceramic and certain plastics)

The method will be explained below using an example

Fig. 1 shows a series of reusable bottles, such as those used in the beverage industry

After the bottles have been turned over, a residual emptying takes place, then loose impurities are rinsed off in a conventional manner.Here the inside and outside of the bottle are moistened evenly, the liquid film is now maintained for the entire treatment time by spraying or similar methods.The bottle to be cleaned is cleaned by a Lock in the RF field requested and remains there until the desired detachment effect of the impurities can be seen, an energy density of over 45 watts / dm ³ has proven to be useful. The bottle then leaves the RF field through a lock and is intensively wound If necessary, this cycle can be repeated several times. If humidification is stopped or reduced at the end of the last treatment cycle, the bottle is largely free of microorganisms

Claims

claims

1. A method for cleaning and / or sterilizing surfaces by moistening and heating, characterized in that the body to be cleaned (with a low dielectric loss factor or non-polar material) with a defined amount of cleaning fluid (with a high dielectric loss factor or polar material) acted upon and irradiated with microwaves, the amount of liquid, amount of energy and time are adjusted so that the adhering dirt and the applied liquid heat up, but a longer heat on the body is avoided.

2. The method according to claim 1, characterized in that the liquid is polar, e.g. Water or water-based solutions.

3. The method according to claim 1 and 2, characterized in that the liquid is applied as a film, for. B by spraying, dipping, rolling or by passing through a liquid curtain or spray.

4. The method according to claim 1 to 3, characterized in that the holding devices for the body to be cleaned also show no reaction to the microwaves, ie have a small dielectric loss factor.

5. The method according to claim 1 to 4, characterized in that the body to be cleaned is preferably guided continuously by an RF field.

6. The method according to claim 1 to 5, characterized in that the action of the RF field is used simultaneously to kill microorganisms, or is used exclusively for this purpose.

7. The method according to claim 1 to 6, characterized in that the position of the body to be cleaned as far as possible prevents accumulation of the liquid, i.e. Allows an unhindered discharge of the liquid and the contaminants contained therein.

8. The method according to claim 1 to 7, characterized in that excess liquid and the impurities contained therein are removed by suitable measures, such as e.g. Vacuum or displace.

9. The method according to claim 1 to 8, characterized in that the treatment in the RF field can be carried out several times, each with the target adapted conditions, such as. B. changed RF intensity or liquid quantity or liquid temperature.