WO2015166515A2

WO2015166515A2 - Container for induced plasma and ionizing radiation

Info

Publication number: WO2015166515A2
Application number: PCT/IT2015/000113
Authority: WO
Inventors: Pier Lorenzo LEVI D'ANCONA; Raoul CANGEMI; Gianni CERZOSO
Original assignee: SARTONI, Stefano; VILLALTA BEGAZO, Milagros
Priority date: 2014-04-28
Filing date: 2015-04-23
Publication date: 2015-11-05
Also published as: WO2015166515A3

Abstract

Container for induced plasma and ionizing radiation (7) characterized by a single chamber; the container walls are formed by a single layer of merged materials (2) (3) seamlessly. In the conglomerate of materials there is at least one material (2) with Faraday cage shape, reflective and impermeable to ionizing radiation and permeable to light radiation emitted by plasma. In the conglomerate of materials there is at least one material (3) permeable to the ionizing radiation made up of microwaves, and impermeable to plasma. Inside the container there will be a gas, that will be ionized at plasma state. The container will have a shape and size appropriate to be resonant cavity for ionizing radiation. A least one entry point (6) of ionizing radiation will be present into the container. The material components of container have a high thermal conductivity, useful to transfer outside the heat produced by plasma.

Description

CONTAINER FOR INDUCED PLASMA AND IONIZING RADIATION

DESCRIPTION Technical Field

This invention is about the heat and light production systems by a radiofrequency source. It concerns a container of ionized plasma and the radiation that ionizes it.

Background art

The current methods for production and containment of plasma that use energy emitted by plasma are composed by at least:

A) Source of ionizing radiation;

B) A wave guide to direct ionizing radiation into the resonance cavity;

C) Resonance cavity of energized waves;

D) Mesh or chamber that contains ionizing radiation;

E) Plasma container partially or completely permeable of ionizing radiation;

F) Container or channel for treatment of substances that use light and heat coming from plasma

Regarding to the production and the containment of ionized plasma and ionizing radiation are known the following patent documents:

FI2013A000154 28/06/2013 - Raoul Cangemi, Cerzoso Gianni: Microwave illuminated stove with energy recovery ; US2005212626A1 29/09/2005 - Toshiyuki Takamatsu: High Frequency Reaction Processing System; WO2006/103287A2 05/10/2006 Pascal Sortias, Xavier Pellet: Microwave Device for treating flux with visible radiation.

It should be noted that in the patents described above:

• The resonance cavity and the plasma container are two separate boxes • The plasma container is always into the resonance cavity

• The volume of plasma container is less than resonance cavity volume

• The plasma container and treatment container (or channel) of substances are installed with frame to obtain appropriate geometries for the proper operation of the system.

• The container (or channel) of irradiation is always located within the volume which is part of the resonance cavity

• The surface, that encloses the resonance cavity, is impermeable to light rays emitted by plasma

The main problem of systems, described above, is the high number of part to be assembled and the construction complexity, it means:

• High cost of production and assembly of components

• Difficult maintenance

• Limited reliability

· Shape and size constraints of the system

• Small surface area of treatment container (or channel)

Disclosure of Invention

The aim of present invention is to provide a simple and reliable device for the production of plasma from low pressure gases and from ionized external source, which is composed by a unique chamber (container) and simultaneously carries out functions of resonance cavity, low pressure gas, plasma container and ionizing radiation container.

A further purpose of present invention is to provide a device for the production and containment of plasma and ionizing radiation with characteristics better than current systems; especially regarding to the simplicity of construction, mechanical reliability, and design without shape and size constraints.

A further object of present invention is to provide a low cost device for heating and lighting systems, characterized of high thermal conductivity and permeability (with more or less selective in frequency); the system could utilize the entire or part of outer surface to illuminate environments and/or heating solids and fluids through radiation, convection, conduction in efficient way.

These and other objects, are characterized of a unique container composed by a single layer assembled of one or multiple materials conglomerated; in particular it is noted that even if the wall of container is assembled of multiple materials, it is seamless therefore the container is considered as only one.

The container carries out simultaneously the following functions:

• To contain the low pressure gas and plasma

• Be permeable (partially or entirely) to the heat and radiation emitted from the plasma

• To operate as a resonance cavity for a ionizing radiation

• To be reflective and impermeable to ionizing radiation in the entire surface except in the entry point of radiation;

• The ionizing radiation can be any kind of radiation; in particular to direct- current, radio frequency, microwave;

• The ionizing radiation is conducted in the container through one or more entry points; the entry points could have any shape and size, for example electrodes, antennas

In a preferred realization, the ionizing radiation is a microwave radiation at frequency of 2450 MHz, produced by a magnetron and conducted toward the container by a waveguide; the container will be permeable to microwave in correspondence of the point of contact with the waveguide, and it will be possible obtain ionized plasma by a mixture of inert gases (eg. Neon, Argon) at pressure of 0,8 atm. Devices will be used for automatic control of internal and external temperature by adjusting the power delivered by the microwave also including pulse-duration modulation. The range of temperatures will be from 0° to 500 ° C. The walls of container will have a high value of thermal conductivity and will be, in one or more points, permeable to light radiation (eg. made of borosilicate glass); in these point the exit of heat and light produced from plasma will be allowed.

In a second method of realization, one and more walls of the container will be impermeable to light radiation emitted from plasma. Moreover, among the materials that compose one or more walls of the container will be one with eutectic properties. Thanks to eutectic properties external container temperature will be limited to specific value. The heat can be extracted from container through a fluid in contact with the surface of the container. In the third methods of container realization, the permeability of light radiation and the imperviousness to ionizing radiation will be obtained through a net of Faraday cage.

It should be noted that in the present invention the container of ionizing radiation is a closed space composed by materials that are reflective and impermeable to radiation. This is a Faraday cage which can be made with metal walls or with a netting. As is know the maximum allowable size of the openings is inversely proportional to the frequency of electromagnetic radiation.

It is noted that a resonance cavity is a volume enclosed by conducting wall in which a oscillating electromagnetic field can be maintained. The frequency of the oscillators depends of the geometry of the resonant cavity. It is noted that in the present invention the low pressure gas container is a container (capsule) in which the gas pressure is less than the atmospheric pressure (101 ,325kPa) and preferably with a pressure between 10 Pa and 0,1 Pa.

As known the plasma is a partially ionized gas with equal number of positive and negative charges; it is therefore electrically neutral but containing free charge carriers and electrically conductive. The plasma is produced by supplying energy to the gas in order to obtain free electrons and ions; the free electrons will involve even neutral atoms through collisions.

The energy for the production of plasma may be provided by discharges in direct- current, discharges induced by waves in radio-frequency and discharges induced by microwaves.

The temperature reached by the plasma depends on the temperature of the ions, due to the high difference of mass between electrons, ions and neutral particles.

With the same quantity of supplied energy, higher is the gas pressure, higher is the number of heavy ions involved in collisions and higher will be the plasma temperature.

Brief description of drawing

Further characteristics and advantages of the invention will be explained during the description of some preferred, but not exclusive, implementation illustrated in the attached drawings, where:

Figure 1. It represents a schematic view of a unique container of plasma and ionizing radiation composed of a conglomerate of different materials, where the walls of container are impermeable to: ionizing radiation and plasma, but permeable to radiation emitted by plasma

Figure 2. It represents a schematic view of a unique container of plasma and ionized radiation composed of different materials, where the walls of container are impermeable to: ionizing radiation, plasma and the light emitted by plasma. In that solution the walls container will have a high thermal conductivity and the outer surface has a corrugated shape

Figure 3. It represents a schematic view of a unique container of plasma and ionized radiation composed of different materials where the walls of container are impermeable to: ionizing radiation, plasma and the light emitted by plasma. In that solution a material with eutectic properties is present into the conglomerate.

Best mode for carrying out the invention

The realization of the present invention will be described bellow with reference to drawings: figure 1 , figure 2 and figure 3.

In figure 1 , the first example of realization of the container. The plasma (1) is induced by ionized radiation (7) which enters into the container from the opening (6) formed by the terminal part of a waveguide. The entrance of ionizing radiation (7) is allowed since the material (2) is permeable to the ionized radiation and impermeable to plasma gas. The material (2) is an electrical insulator, it has a good thermal conductivity and it is permeable to light emitted by plasma (eg. borosilicate glass).

The material (3) is composed of a net or a perforated plate. It acts as a Faraday cage for ionizing radiation (microwave) that is then reflected; this structure also enables the light produced by plasma to get out the outer surface of the container. The material (3) will be a metal or metal alloy with high thermal conductivity property.

With the above listed characteristics of the material (2) and material (3) we have the entire outer surface of the container useful for heating and lighting.

The material (3) is entirely merged in the material (2) except that in some flanges (4) which protrude outwardly; the flanges (4) can also be used as points of heat extraction from container; the heat extracted by the parts (4) can be exchanged by conduction or convection.

The heat extraction using only the flanges (4) and leaves cold the rest of the container surface, can be obtained using a material (2) with characteristics of thermal insulation.

In operating temperature range, the material (2) and the material (3), must ensure the maintenance of the physical and mechanical characteristics of the conglomerate; this can be achieved by using materials with similar thermal coefficient of expansion (eg. borosilicate glass for the material (2) and Iron-Nickel alloy or iron-nickel-cobalt alloy for the material (3)).

Figure 2 shows a container where walls are impermeable to light produced by the plasma; it is obtained merging a material impermeable to ionizing radiation and to light produced by plasma; eg a metal foil or metal alloy.

In this case, the outer surface of the container has a corrugated shape; it allows to increase the surface area for heat exchange.

Figure 3 shows a container where the conglomerated walls include a material (5) with eutectic properties (for example tin-lead alloy or tin), which the melting point is lower than material (2) and material (3) and impermeable to light radiation. When the plasma exceeds the melting temperature of the material (5), it begins to melt and maintain a constant temperature, preventing the rise of temperature on the outer surface; in this way there is a container which transfers heat to the outside with a maximum temperature controlled by the physical characteristic of the material. The conglomerate of materials (2), (3) and (5) will be assembled in order to the material (5) will be retain within the wall of container during the melting and solidification.

Industrial applicability

An application of the present invention may be the use of the container as a kitchen heating plates. In this case, the container would have a particular form for example a parallelepiped or a disc, and the ionizing radiation may be generated by a magnetron with working frequency of 2.450MHz. The regulation of the magnetron power would provide one or more operating temperatures of the plate

Another application of the present invention may be the use of the container as a decorative element of lighting and heating. In this case the container will have a parallelepiped shape with wall made of Faraday cage and borosilicate glass; it will be permeable to heat and light emitted by plasma. The particular shape would make it suitable to be assembled in series so as to form walls or panel wall inside living spaces.

Claims

CONTAINER FOR INDUCED PLASMA AND IONIZING RADIATION CLAIMS

1. Container for induced plasma (1 ) and ionizing radiation (7) characterized by a single chamber; the container walls are formed by a single layer of merged materials (2) (3) seamlessly. In the conglomerate of materials there is at least one material (2) with Faraday cage shape, reflective and impermeable to ionizing radiation and permeable to light radiation emitted by plasma. In the conglomerate of materials there is at least one material (3) permeable to the ionizing radiation made up of microwaves, and impermeable to plasma. Inside the container there will be a gas, with a pressure less than atmospheric pressure, that will be ionized at plasma state. The container will have a shape and size appropriate to be resonant cavity for ionizing radiation. A least one entry point (6) of ionizing radiation will be present into the container. The material components of container have a high thermal conductivity, useful to transfer outside the heat produced by plasma. In the container will be present at least one heat extraction device.

2. As claimed in claim 1 , container characterized by having a part (4) of resonance cavity extended to inside and/or outside of the container with the aim of increase the heat exchange to the outside.

3. As claimed in claim 1 or 2, container characterized by having the resonance cage formed by a corrugated foil (fig.2)

4. As claimed in claim 1 or 2, container characterized in that Faraday cage is formed by continuous surfaces and therefore not permeable to the light radiation emitted by plasma.

5. As claimed in claim 1 or 2, container characterized in that one of the material (5), fig (3) component of the conglomerate have eutectic properties and melting point between 60 °C and 350 °C and preferably a metallic tin-lead eutectic alloy or a single metal with low melting point.

6. As claimed in claim 1 or 2, container characterized in that Faraday cage is composed of pipes made of material (2); in which flows a fluid to extract heat from plasma; these pipes have external endings (4a) that could be connected with a external heating or cooling circuit.

7. As claimed in claim 1 or 2, container characterized by having any shape or size

8. As claimed in claim 1 or 2, container characterized in that one or more surface areas works as a frequency filter for radiation produced by plasma

9. As claimed in claim 1 or 2, container characterized by having one o more surface areas with a thermal conductivity different from the rest of the surface.

10. As claimed in claim 1 or 2 and 6, container characterized in that Faraday cage is used to expand the range of plasma operating temperatures, in which the coefficient of thermal expansion of conglomerated materials can be considered similar or compatible.

11. As claimed in claim 1 or 2, container characterized in that the conglomerate contains any number of materials.

12. As claimed in claim 1 or 2, container characterized in that ionizing radiations could be any type of radiation, in particular direct current, radiofrequency, microwaves, laser.

13. As claimed in claim 1 or 2, container characterized by ionizing radiation is introduced into the container in any number of entry points; the entry points will have any shape and size and will be suitable to ionizing radiation; eg. electrodes, antennas, waveguide.