Method for treating the air in a display cabinet and display cabinet for carrying out said method

Abstract

In a method for air treatment in a display cabinet for the storage and/or display of objects, whose walls, floor and roof structure more or less enclose the inside space of the display cabinet and in which a forced inflow of air from an air delivery system connected to the inside space (1) of the cabinet maintains a slight excess pressure compared with the air outside it, the said airflow passes through suitable dust or gas filtration means before entering the cabinet and its air humidity is adjusted and/or controlled by means of a cooling device. After filtration, the airflow passes into a container (2) holding a liquid (7), the said liquid being kept free from germs by suitable means. In this manner and in a simple way, a completely germ-free atmosphere is produced inside the display cabinet. A display cabinet for implementing the method has a corresponding structure.

Description

The invention concerns a method for air treatment in a display cabinet for the storage and/or display of objects, whose walls, floor and roof structure more or less enclose the inside space of the display cabinet and in which a forced inflow of air from an air delivery system connected to the inside space of the cabinet maintains a slight excess pressure compared with the air outside it, this airflow passing through suitable dust or gas filtration means before entering the cabinet and having its air humidity adjusted and/or controlled, and a corresponding display cabinet for implementing the method.

Such a method and a corresponding display cabinet are already known. Thus, DE-PS 38 05 212 C2 describes a cabinet for the storage and/or display of objects, in which, for the protection of the objects displayed, the air surrounding them inside the cabinet is kept not only free from dust but also within a desired range of air humidity. It is also possible to fill the inside space with a neutral gas, if this is required for the protection of the objects displayed.

Besides freedom from dust, controlled humidity, etc., the case can also arise that certain objects inside the display cabinet require surroundings free from germs.

Thus, the purpose of the present invention is to indicate a method of the type mentioned above, in which the airflow passing into the display cabinet is rendered germ-free, and to supplement the equipment of a display cabinet of the type mentioned at the start, in such manner that a germ-free atmosphere is produced inside the cabinet.

With a method and equipment of the type mentioned earlier, these objectives are achieved by passing the airflow, after filtration, into a container holding a liquid and providing in the said liquid a catalyser by means of which the air is rendered completely free from germs.

Since even an airtight cabinet is never completely impervious to gas and also, when it is opened, air from outside can enter the inside space, the maintenance of a slight excess pressure compared with the ambient air produces a flow of air from the inside outwards, with the result that clean, cooled and germ-free air has to be fed continuously into the inside space, whereby the air throughout the inside space of the display cabinet is completely renewed over a period of a few days, depending on its size. In this way a completely germ-free atmosphere is achieved after a certain time.

DE-PS 198 26 930 C2 describes a climate-controlled display cabinet, in which a flat heat exchanger is in the inside space of the cabinet and a collecting and humidifying tray is arranged under it, the heat exchanger being connected to a refrigerating machine. From the description it can be seen that by means of a fan, a controlled flow of air can be passed through a number of cabinets connected in series. In contrast, in the present invention the controlled airflow first passes into a container holding a liquid and then to a cooler.

The climate-control of a display cabinet is also the object of WO 01/84986 A1, in which the air inside a display cabinet is propelled through a dehumidifying and heating/cooling device. The said device contains a hygroscopic medium, for example silica gel, which has to be replaced as soon as it has absorbed too much water.

An air purification system in which germs are also removed from the air is described in DE-OS 199 03 022 A1, in which the air is treated by an electrostatic device. Such a device is intended for use in many ways, such as in the air ducts of climate-control units in which the heated or cooled air is subjected to germ removal. The description does not mention how such germ removal is to take place in the case of display cabinets. In contrast, in the present invention the air humidity of the already germ-free air is adjusted and/or controlled in combination with a cooling device.

In collaboration with the liquid containing an additive, the catalyser according to the invention frees the air that has been brought into contact with the liquid from germs.

Other advantages emerge from the subordinate claims relating to the method and device according to the invention.

The invention will be explained in more detail with reference to two example embodiments illustrated in the drawing, which shows:

FIG. 1: Section through a container of liquid with a flat catalyser, and

FIG. 2: Section through a container of liquid with a sponge, which is surrounded by a catalyser

The container 2 shown in FIG. 1 is closed by a cover 10 and contains a liquid 7, for example distilled water. Into the headspace above the liquid 7 is passed an airflow 5 freed from the ambient air dust, for example by passing through an appropriate filter. Above the liquid 7 the air picks up moisture, and the air so treated is passed into a cooling device 4 in which the humidity of this air is adjusted and regulated to a specified value. The air 6 treated in this way is then passed by means of a pump (not shown) into the inside space of the display cabinet. The pump serves to maintain a slight excess pressure in the inside space 1 of the cabinet, and only has to deliver an amount of air sufficient to make up for any air that escapes to the outside by leaking out of the cabinet. The cooling device 4 and the pump (not shown) are controlled by a control unit 3 to which sensors (not shown) for air pressure and humidity positioned in the inside space 1 of the display cabinet are connected, so that the pump is correspondingly controlled as a function of the specified air pressure, and the cooling device 4 as a function of the specified air humidity. A monitoring device (not shown) for the filling level of liquid 7 in the container 2 can also be connected to the control unit 3, and by means of an acoustic and/or visual signal this indicates when the liquid reserve in the container 2 should be topped up.

At the bottom of the container 2 in the liquid 7 there is a catalyser 8 in the form of a flat grid held between the two flat surfaces of respective protective gratings 9, and it must be ensured that the catalyser is covered by liquid 7 at all times.

FIG. 2 shows a second embodiment in which the dust-free airflow 5 is passed into a sponge 11, the sponge 11 being enveloped by the grid of the catalyser 8. The humidified air escapes from the sponge 11 and rises to the surface of the liquid 7. The further treatment of the cleaned and humidified air 6 then takes place in the manner already described. The sponge must be covered by the liquid 7 at least sufficiently for the catalyser 8 to be below the surface of the liquid 7.

The catalyser can take any form such as wire, sheet, chips or powder, which will ensure the presence of a sufficiently large active surface area. The alloy used for the catalyser consists of 10 to 80 mass-% of cobalt, 5 to 50 mass-% of nickel, 5 to 20 mass-% of tungsten and 5 to 25 mass-% of chromium, heat treated in an atmosphere containing oxygen for 0.05 to 3 hours at temperatures in the range 250° to 1,250° C. Such a catalyser remains highly active for prolonged periods.

The collaboration of the catalyser 8 with water as the liquid 7 already frees the air in the inside space 1 of the display cabinet from germs. In particular cases when the objects on display in the cabinet so allow or require, the liquid 7 can for example also contain a certain amount of hydrogen peroxide.

The humidified and germ-free air is passed into the inside space 1 of the display cabinet, whereby the air surrounding the displayed objects in the cabinet also becomes free from germs since after some time the air in the inside space 1 will have been completely renewed due to leaks, and the air can then be kept continually free from germs.

In the description of the two embodiments shown in FIGS. 1 and 2 It has so far been assumed that the germ-free air is then passed into a cooling device 4 and thence to the inside space 1 of the display cabinet. It is also conceivable, however, to pass the air first into a cooling device 4 and only then to subject it to the treatment for germ removal. Depending on the ambient temperature of the display cabinet, the cooling device 4 can serve to adjust the air humidity and/or temperature of the air in the inside space 1 of the cabinet, by heating or cooling the air. In this it is also conceivable, if the cooling device 4 is of appropriate design, i.e. when in accordance with the state of the art, in combination with water a specified air humidity and/or air temperature can be established, to combine the cooling device 4 with the device according to the invention for eliminating germs from the air, since the water serves both to adjust the air humidity and/or temperature and also, by virtue of the additive in combination with the catalyser, to eliminate germs from the air.

The air 5 treated to remove dust can all come from the air outside the display cabinet, but it is also conceivable for some of this air to come from the inside space 1 of the cabinet, whereby the air replacement in the inside space 1 is accelerated.

The devices described for humidifying and eliminating germs from the air in the inside space 1 of a display cabinet can be positioned individually as closed units inside the cabinet. It is also conceivable, however, if there are several display cabinets, to provide a common device to which only the inside space 1 with the air duct(s) and with the sensors is connected.

The invention can be used both for display cabinets in which objects are set out for display, and with cabinets serving only for the storage of objects.

Claims

1. Method for the treatment of air in a cabinet for the storage and/or display of objects, whose walls, floor and roof structure more or less enclose the inside space of the cabinet and in which a forced inflow from an air delivery system connected to the inside space of the cabinet maintains a slight excess pressure compared with the air outside it, this airflow passing through suitable dust or gas filtration means before entering the cabinet and having its air humidity adjusted and/or controlled, wherein after filtration the inflowing air (5) passes into a container (2) holding a liquid (7) and a catalyser (8) is present in the liquid (7), by means of which the air is completely free from germs.

2. Method according to claim 1, wherein the liquid (7) consists of water.

3. Method according to claims 1, wherein the liquid (7) contains an additive.

4. Method according to claim 1, wherein the catalyser (8) consists of a wire grid made from a particular alloy.

5. Method according to claim 4, wherein the wire grid is made as a mat and is held between two protective gratings (9) of at least the same size.

6. Method according to claim 1, wherein the airflow (5) is passed over the surface of the liquid (7) in the container (2)

7. Method according to claim 4, wherein the airflow (5) is passed into a sponge (11) wetted by the liquid (7), which is enveloped by the wire grid.

8. Method according to claim 1, wherein the airflow (5) passing into the container (2) consists of two parts, one part from the outside air and one part from the air inside the display cabinet.

9. Method according to claim 1, wherein the germ-free air passes into a cooling/heating device (4), which serves to maintain a specified temperature and/or air humidity.

10. Method according to claim 1, wherein the airflow (5) first passes into a cooling/heating device (4) which serves to maintain a specified temperature and/or air humidity, and is then freed from germs.

11. Method according to claim 10, wherein the cooling/heating device (4) regulates the specified temperature and/or air humidity by means of a liquid, this liquid being identical to the liquid (7) of the catalyser (8).

12. Display cabinet for implementing the method according to claim 1, whose walls, floor and roof structure more or less enclose the inside space of the display cabinet and in which a forced inflow of air from an air delivery system connected to the inside space of the cabinet maintains a slight excess pressure compared with the air outside it, this airflow passing through suitable dust or gas filtration means before entering the cabinet and having its air humidity adjusted and/or controlled, wherein after filtration the airflow (5) is passed into a container (2) holding a liquid (7) and in the liquid (7) there is a catalyser (8), by means of which the air subsequently passed to a cooling device is rendered completely free from germs.

13. Display cabinet according to claim 12, wherein the liquid (7) consists of water and contains an additive.

14. Display cabinet according to claim 12, wherein the liquid (7) contains a certain amount of hydrogen peroxide.

15. Display cabinet according to claim 12, wherein the catalyser (8) consists of a wire grid made from a particular alloy.

16. Display cabinet according to claim 15, wherein the wire grid is made as a mat and is held between two protective gratings (9) of at least the same size.

17. Display cabinet according to claim 15, wherein a sponge (11) is enveloped A by the wire grid and the airflow (5) is passed through the sponge.

18. Display cabinet according to claim 12, wherein the airflow (5) passing into the container (2) consists of two parts, one part from the outside air and one-pain from the air inside the display cabinet.