RU2113073C1 - Device for initiating discharge in high-frequency inductance plasmatron - Google Patents

Abstract

FIELD: plasma engineering; plasmatrons used for heating gases. SUBSTANCE: device has high-melting metal electrodes and inductance turn secured in insulator. Turn ends are connected to electrodes arranged along longitudinal center line of turn. Inductance turn is made of material affording elastic strain. Device may incorporate annular nonretentive core placed inside inductance turn. EFFECT: improved reliability, reduced power and plasma-forming gas requirement due to reduced discharge-initiating time and dispensing with external power supply, facilitated discharge initiation procedure. 2 cl, 2 dwg

Description

 The invention relates to a plasma technique and can be used to excite a discharge in the HF plasmatrons used to heat gases.

 A device for initiating a discharge is known, which contains an electrode made in the form of a rod of refractory metal, to which an electric potential is supplied from an inductor or an extraneous energy source (1).

 The disadvantages of the device are the complexity of the organization of the process of excitation of the discharge due to the presence of moving contacts and an external source of electricity, as well as insufficient reliability with increased internal dimensions of the plasma torch.

 As the closest analogue of the invention, a device for exciting the discharge was selected, which uses carbon-graphite rods in the high-frequency field of the plasma torch [2]. The disadvantage of this device is the significant time of plasma excitation and energy costs for heating the mass of the rods, compensation for heat loss, as well as a significant inert gas consumption for exciting the discharge.

 The objective of the invention is to provide a device for initiating a discharge in an HIV plasmatron with higher performance properties.

 The problem is solved in that the device for exciting the discharge in the RFI plasmatron, containing two coaxially placed electrodes and an insulator, is equipped with an inductive coil mounted in the insulator, while the ends of the coil are connected to the electrodes located along its longitudinal axis of symmetry, and the coil is made of material, providing the possibility of elastic deformation of the coil.

 In addition, the device contains an annular core of soft magnetic material placed inside the inductive coil.

 In FIG. 1 shows a General view of the device, a longitudinal section; in FIG. 2 is a section AA in FIG. one.

 The proposed device is shown introduced along the longitudinal axis into the housing 1 of the plasma torch, placed in a dielectric tube 2.

 The device is mounted in an insulator 3 and contains an inductive coil 4 connected by radial taps (ends) 5, 6 with electrodes 7, 8, respectively.

 The inductive coil 4 is made elastically deformable, for example, from a tungsten wire with a diameter of 2 mm.

 In the insulator 3, a socket 9 is made, in which an annular core 10 of magnetically soft material, for example, ferrite M100NN, M600NN, is placed.

 A radial outlet 5 is inserted into the socket 9 through the hole 11 made in the insulator 3 and, respectively, in the core 10, which ensures the fastening of the inductive coil concentrically to the core and the placement of the electrodes 7, 8 along the longitudinal axis of symmetry of the coil.

 The device operates as follows.

 With a short-term introduction of the device into the plasma torch chamber (using a metal or dielectric rod to which the insulator 3 is attached), at the moment of stop due to inertia forces oscillations of the electrode 8 occur, which are mounted on the free end of the radial tap 6 of the inductive coil 4. When the oscillatory motion is reversed electrode 8, due to the elasticity of the inductive coil, its ends are closed through the electrodes 7, 8, while the current flows under the influence of a high-frequency electric agnitic field of plasmatron. The opening of the electrodes 7, 8 when the electrode 8 is returned to the equilibrium position causes a discharge between the electrodes, as a result of which the main induction discharge is excited.

 The location of the inductive coil near the walls of the plasma torch, as well as the presence of a ferrite core 10 increases the inductive coupling of the coil with the high-frequency electromagnetic field of the plasma torch, which increases the power of the initiating discharge.

 Placing the electrodes along the longitudinal axis of the coil provides favorable conditions for gas-dynamic stabilization and instantaneous propagation of a volume induction discharge in all radial directions, since the release of the electromagnetic field power of the induction plasmatron increases in the direction from the axis to the walls of the plasma torch chamber.

 The closure and opening of the electrodes 7, 8 due to the elastic deformation of the inductive coil eliminates the need to increase the power of the plasma torch in the process of excitation of the discharge to ensure the breakdown of the interelectrode gap.

 These factors together increase the reliability of the discharge excitation in the RFI plasmatron, reduce the energy consumption and plasma-forming gas by reducing the time required to excite the discharge, and also simplify the organization of the discharge excitation process by eliminating moving contacts, additional power sources and associated high-frequency breakdowns in the outer region of the plasma torch.

 Sources of information taken into account when preparing the application.

 1. RF-microwave plasmatrons (Dresvin S.V. et al. - Novosibirsk: Nauka, Sib. Branch, 1992 - (Low-temperature plasma, v. 6), p. 17.

 2. Dresvin C.V. and other Physics and technology of low-temperature plasma. - M .: Atomizdat, 1972, p. 78 (prototype).

Claims (2)

 1. A device for initiating a discharge in an RFI plasmatron containing two coaxial electrodes and an insulator, characterized in that it is equipped with an inductive coil fixed to the insulator, while the ends of the coil are connected to electrodes located along its longitudinal axis of symmetry, and the coil is made of material, providing the possibility of elastic deformation of the coil.  2. The device according to p. 1, characterized in that it contains an annular core of soft magnetic material located inside the inductive coil.

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