FR2574298A1 - Device for sterilisation by means of ducts with high temperature gradient - Google Patents

Abstract

The device with ducts with high temperature gradient of the invention is based on classical thermodynamic principles, which optimise the thermal method of air sterilisation, while reducing to a very great extent the size of the installation. The high temperature gradient produced inside the ducts is capable of eliminated numerous microorganisms passing through the ducts, for example those transported by air convection produced by this device. Because only a small quantity of air is treated per unit time, there is no considerable increase in the ambient air temperature in the places where the device is installed. The total energy consumption of this device is approximately 5 W/h/m<3>.

Description

The present invention relates to the effect caused by the passage of continuous air flow through a series of small diameter ducts in which energy is dissipated by the Joule effect. The high thermal gradient produced inside the aforementioned ducts has an average value of 2200C and is therefore capable of destroying the protein membrane which envelops most of the bacteria and viruses found in the air.

The thermal effect as a sterilizing agent is widely used and known universally in the same way as the Joule effect is known as a heat source.

The present invention introduces, as a novel approach, the use of ducts with a high thermal gradient, which increase the sterilizing action by the Joule effect, thus improving its efficiency with regard to the destruction of microorganisms present in the air, without cause noticeable changes in the temperature and the ambient air in the rooms where this device is installed.

The specified scientific and technical principles on which this device is based are in the field of thermodynamics, mainly the convection of gases through ducts of small diameters, axially heated.

This invention has a wide range of applications, for example that which requires the removal inside rooms or buildings of microorganisms present in the air and the modification of the relative humidity in the air without causing considerable change in ambient temperature.

This sterilization device can be designed to accommodate any volume of air because there is a very well defined correlation between the volume and the power of the device.

Nowadays, several methods are used to achieve sterilization of air in places where the proliferation of microorganisms is high. The most classic methods are as follows
- the direct use of the Joule effect by simple heating. This method does not show any thermodynamic improvement, which results in low efficiency with regard to the sterilization effect.

- the use of incandescent lamps which can be considered as included in the previous method, since the thermal effect comes from the lamps.

- the use of ultraviolet radiation in air-flow chambers.

The advantages of the present invention over the above-mentioned process are as follows
- increase in efficiency in terms of sterilized volume / energy consumed ratio, which is due to the ducts with a high thermal gradient, with axial heating,
- simplicity of the heating method, since high efficiency is achieved by judiciously choosing the parameters of the ducts according to the laws of thermodynamics.

- the device is protected against short-circuits by means of a suitable fuse and no considerable increase in the temperature of the ambient air is observed.

According to certain measurements carried out on prototypes of this device used at its ideal operating weight, a consumption of 5 watts / hour / m 3 is observed while supplying air with a negligible quantity of microorganisms.

When we compare these results with those obtained with incandescent lamps, we can observe for the latter a lower factor of 20 than that of the device of the invention, that is to say, for the same initial quantity of microorganisms in the air, a sterilizing system using incandescent lamps requires 100 watts / hour / m3 in order to obtain a negligible amount of microorganisms in the air.

By taking into account these experimental results, it can be concluded that the device for sterilizing the ducts with a high thermal gradient, produced by the Joule effect, is considerably effective when compared with the existing variants. The Joule effect in this device can be produced by passing an electric current through a very resistant element, for example a resistance in chromium / nickel wire disposed axially inside the conduits designed according to the principles of thermodynamics.

The invention will be better understood on reading the following non-limiting description of an embodiment of conduits, with reference to the appended drawing in which
Figure 1 shows the electrical diagram of the device associated with the present invention
Figures 2, 3 and 4 show respectively the perspective, top and front views of the duct system according to the present invention.

Figures 5, 6 and 7 are respectively rear, front and bottom views of the casing of the device associated with the present invention.

Referring more specifically to the drawings, Figure 1 shows the electrical diagram on which we can see the fuse F1 for the protection of the device, a light-emitting diode serving as an operating or shutdown indicator, and the control element. heater, made of a resistant nickel / chromium wire, the essential characteristics of which are chosen according to the volume of air to be sterilized.

FIG. 2 represents the top view of the ducts with a high thermal gradient, which are also designed according to the volume of air to be treated. The material constituting the ducts is a refractory material in order to optimize the heat transfer to the air which circulates by convection.

Figure 3 is a top view of the high thermal gradient duct device. It can be seen that the ducts have a circular shape although any geometric shape of said ducts may be suitable as a variant.

Figure 4 shows a front view of the duct device mentioned above.

FIG. 5 represents the rear view of an aluminum casing in which this device is housed.

Figures 6 and 7 represent respectively the front and rear views of the housing specified in the previous paragraph.

The application of the invention specified above relates directly to the optimization of devices suitable for the thermal sterilization of air.

The present invention can be used in wardrobes, rooms, warehouses of perishable goods and other places where the action of microorganisms must be prevented.

This device is also very effective against mold and bad odors which are usually encountered in wardrobes, attics, basements and the like.

It can also be used in hospitals and clinics where high level biological activity in the air must be kept to a minimum.

Claims (2)

1. Device for sterilizing the air by means of ducts with a high thermal gradient, heated axially by a resistant nickel / chromium wire, having characteristics imposed by the volume of air to be sterilized. 2. Device for sterilizing air by means of high thermal gradient conduits according to claim 1, characterized in that the conduits are preferably cylindrical and heated directly or indirectly by means of a high thermal gradient method.