Electric heating – Metal heating – By arc
Patent
1994-12-29
1996-01-23
Paschall, Mark H.
Electric heating
Metal heating
By arc
21912148, 21912154, B23K 1000
Patent
active
054866740
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention concerns a plasma torch preferably for energy supply for chemical processes. The plasma torch is provided with several tubular electrodes which are located coaxially with one another. The electrodes are connected to an electrical power supply. Gas is supplied through the internal electrode and in the spaces between the electrodes. High temperature plasma is formed by means of the gas which is heated by the electric arc which extends between the electrodes.
BACKGROUND OF THE INVENTION
In order to obtain desired chemical reactions in gases or in mixtures of gas and liquid or solid particles, in some cases energy has to be supplied. Some such chemical reactions in gases take place at extremely high temperatures, in the order of 1000 to 3000 degrees. It is also necessary to be able to check the amount and the temperature of the gas in order robe able to control and regulate a chemical process of this kind. By exploiting the technology of heating gas in an electric arc in a plasma torch the above-mentioned requirements can be achieved.
The plasma torches known hitherto have been used first and foremost for heating gas for the purpose of welding and cutting steel, for heating in metallurgical processes and in laboratory experiments. Since they often have a high consumption of plasma gas, as it is the gas transport through the torch which dissipates the heat generated in the arc, in some applications they will be less favourable from the point of view of heat economy.
SUMMARY OF THE INVENTION
The object of the present invention, therefore, is to provide a plasma torch which has good heat economy, long electrode life and an operationally reliable design which is suitable for industrial application.
This object is achieved with a plasma torch which is characterized by the features in the claims presented.
The plasma torch consists of several tubular electrodes located coaxially outside one another. The plasma torch is closed at one end, while the other end is open. The electrodes can be moved axially in relation to one another. The electrodes are preferably electrically insulated from one another and have connections for electrical power. Through the internal electrode and in the space between the electrodes there are provided connections for the introduction of gas. High temperature plasma is formed by the gas which is heated and ionized by the electric arc.
In the invention three or more tubular electrodes are located coaxially outside one another. In its simplest form the torch is provided with three electrodes; a central electrode, then an auxiliary electrode and finally an outer electrode. In other embodiments one or more electrodes may be located coaxially outside the outer electrode. Annular passages are formed between the electrodes. Between the central electrode and in the annular passages plasma-forming gas and/or reactant can be introduced.
An inert gas such as nitrogen or argon, for example, can be used as a plasma-forming gas. Such a gas will not usually participate in or affect the chemical reaction taking place in the torch. The plasma-forming gas can also be the same type of gas which is formed as a product of the reaction in the plasma torch.
The reactant can be pure gas or gas mixed with liquid or solid particles with which it is desirable for chemical reactions to take place in the plasma flame, for example a thermal decomposition. The reactant in itself can also be the plasma-forming gas.
The electrodes in the plasma torch are solid and can be consumable. As an electrode material, it is preferable to use graphite, which has a high melting point and requires little cooling.
This constitutes a substantial simplification of the design of he plasma torch and is important for the improvement of the torch's energy efficiency.
The electrodes can be moved axially in relation to one another. Adjustment of the electrodes in relation to one another offers the possibility of altering the average length of the arc and thereby the working voltage, which in t
REFERENCES:
patent: 3521106 (1970-07-01), Hess
patent: 3832513 (1974-08-01), Klasson
patent: 4009413 (1977-02-01), Elliott et al.
patent: 4275287 (1981-06-01), Hiratake
patent: 4341941 (1982-07-01), Tateno
patent: 4390772 (1983-06-01), Hiratake
patent: 4481636 (1984-11-01), Curr et al.
patent: 4710607 (1987-12-01), Wilhelmi et al.
patent: 5103072 (1992-04-01), Eikeland et al.
patent: 5144110 (1992-09-01), Marantz et al.
patent: 5210392 (1993-05-01), Labrot et al.
Haugsten Kjell
Hox Ketil
Hugdahl Jan
Lynum Steinar
Kvaerner Engineering AS
Paschall Mark H.
LandOfFree
Plasma torch device for chemical processes does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Plasma torch device for chemical processes, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Plasma torch device for chemical processes will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1506220