JPH03173099A - Plasma toach introducing plasma gene gas by non-cooling - Google Patents

Abstract

PURPOSE: To provide a plasma torch which can be simplified and can also guarantee performance similar to a conventional plasma torch by constituting so that a rotary member does not have an inside cooling means. CONSTITUTION: An inner wall 17A of a rotary member 17, the ends 5B and 6B of an electrode and a front face 3A of a support body 3 demarcate an inside chamber 18 to introduce plasmagene gas through a hole 17B in a crossing direction on the introducing member 17. An inside cooling means is not arranged in the introducing member 17. Cold plasmagene gas introduced to the inside chamber 18 approaches the inner wall 17A of the introducing member, and constitutes a heat barrier for the protection against a high temperature generated by an electric arc 11 in the inside chamber 18. Therefore, the introducing member 17 can be fairly simplified. Therefore, a plasma torch which enables a swirl effect advantageous to the plasmagene gas and enables a small necessary space, can be obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an electric arc plasma torch that is provided in the torch and introduces plasma gene gas into an internal chamber traversed by an electric arc generated between electrodes. It is something. Note that the temperature of the plasma is 10,000 ℃ at the exit of the torch.
It may exceed ℃.

[Conventional technology]

In commonly known plasma torches, two electrodes, one in extension of the other, tubular and coaxial, are each arranged in a support. Due to the high temperatures, it is necessary to provide a cooling circuit between each electrode and the surrounding support. Furthermore, in order to create an electric arc between the two electrodes, means are provided for starting this electric arc, which means are probably of the type of electric discharge created between the two electrodes. or,
For example, a short-circuit type using an auxiliary starting electrode.

Plasma torches often include at least one electromagnetic coil disposed around one electrode support to allow movement of the catching feet of the electric arc and avoid premature wear of the inner surface of the tubular electrode. There is.

Regarding the means for introducing a plasma gene gas, such as air, into the internal chamber of the torch, they include a rotating member coaxial with said electrodes and defining said introduction chamber by said electrodes and their support. There is.

The rotary member is provided with transverse holes to allow the introduction of plasma gene gas from the supply circuit into the internal chamber. Since the rotating member is directly exposed to the thermal radiation generated by the chemical reaction caused by the electric arc and the plasma gene gas, the rotating member is made of metallic material and further includes a cooling circuit. For this purpose, axial passages are provided in the rotating member for the circulation of cooling fluid. For example, on one side these passages communicate with an external annular groove provided in the rotating member into which the cooling fluid arrives, and on the other side these passages communicate with the downstream electrode (
It is in communication with the cooling circuit (regarding the circulation of plasma gene gas). This arrangement allows the same cooling fluid to be directed into the cooling circuit of the introduction member and the downstream electrode.

[Problem to be solved by the invention]

However, if the introduction member is metal and therefore a conductor,
It is absolutely necessary to provide an electrical non-conductor between the two electrodes to ensure maximum insulation. For this,
A non-conducting device is provided between the introduction (rotating) member and the upstream electrode, which can also act as a heat shield for the upstream or rearward part of the l.-chi.

Thus, the defects caused by these plasma torches are easily understandable. The complexity of the plasma gene gas introduction elements, which are provided with internal cooling circuits due to the high temperatures encountered, and the need to add non-conducting equipment for the reasons mentioned above, increases the space requirements of the plasma torch and these This results in an increase in the manufacturing cost of the torch.

Claims (7)

[Claims] (1) two coaxial, tubular electrodes, one extending from the other, each disposed within a support provided with an associated cooling circuit; means for creating the start of an electric arc between two electrodes; and means for introducing plasma gene gas between the electrodes, comprising a rotating member coaxial with the electrodes, the rotating member and its support. A plasma torch consisting of a body defining a chamber into which plasma gene gas is introduced through a transverse hole made in the rotating member, characterized in that said rotating member does not have means for internal cooling. Plasma torch. 2. The plasma torch of claim 1, wherein the rotating member is made of an electrically nonconducting, nonmetallic material. 3. The plasma torch of claim 1, wherein said rotating member is made from a plastic material. (4) The plasma torch according to claim (3), wherein the plastic material is polytetrafluoroethylene. 5. The plasma torch of claim 1, wherein the rotating member has a crown-shaped cross section. (6) Claim (1), wherein holes for introducing plasma gene gas are regularly distributed around the rotating member.
Plasma torch as described. (7) the geometric axes of the transverse introduction holes for the plasma gene gas included in a plane perpendicular to the axis of the plasma torch, instead of being concentrated in the direction of the axis of the plasma torch; 2. The plasma torch according to claim 1, wherein the plasma torch is slightly deviated from a position where it is intended to be concentrated in the direction of the heart.