JPS6166341A - Ignitron - Google Patents

Abstract

PURPOSE:To stabilize plasma by surrounding an outer peripheral wall of a vacuum tub accommodating an anode and a mercury cathode with cylindrical return current conductor and helical return current conductor and generating stable magnetic field on a plasma generating unit. CONSTITUTION:An outer peripheral wall of a vacuum tub 3 accommodating a mercury cathode 6 and an anode 2 is surrounded by a cylindrical return current conductor 21 whose lower end portion is connected to a cathode terminal 9 and a helical return current conductor 22 whose upper portion is electrically connected to the conductor 21 and other portions of which are insulated by arranging them in parallel to form ignitron performing switch action. And current is flowed in the conductor in the opposite direction of the current direction of plasma P and flowed from the upper end to the lower end in the helical conductor 22 to generate stable magnetic field on a plasma generating unit of the vacuum tub 3. Then plasma can be stabilized and energy flowed into plasma can be reduced and life of the ignitron can be prolonged.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ignitron, and particularly to an ignitron used as a switching element.

[Conventional technology]

Conventionally, there has been a device of this type as shown in FIG.

In the figure, an anode to which an anode terminal 1 is connected is housed in the upper part of a cylindrical vacuum chamber 3, and a cooling cylinder is provided surrounding the vacuum chamber 3. A thermostat mounting plate S is attached to the outer wall of the cooling tube. A mercury cathode 6 is housed at the bottom of the vacuum chamber J, and an igniter lead wire t connected to an igniter 7 located above the mercury cathode B is led out below the vacuum chamber 3. There is. Cathode terminal whose top end is connected to mercury cathode O? extends below the vacuum chamber 3. Further, a cooling water port 10 and a cooling water outlet // communicating with the space between the vacuum chamber 3 and the cooling cylinder are provided to form a cooling system. 1 is an exhaust pipe attached to the bottom wall of the vacuum chamber 3. A return current conductor rod 13 connected to the cathode terminal and branched extends upward in parallel along the outer side of the vacuum chamber 3.

The conventional ignitron is constructed as described above, and operates by applying an appropriate trigger to the igniter 7 while voltage is applied between the anode terminal L and the cathode terminal D from an appropriate power source. Then, some of the mercury in the mercury cathode B evaporates, and the mercury vapor brings electrical continuity between the anode 2 and the mercury cathode 6, causing current to flow in the direction of the arrow. The return current flows through the return current conductor rod/J as shown by the arrow, thus forming a closed current circuit.In other words, at the point where the switch is closed, the ignitron body is generates heat, but in order to suppress this heat generation, a cooling system using cooling cylinders is operated.

[Problem that the invention seeks to solve]

In the conventional ignitron as described above, the discharge occurs in the so-called normal 2-pinch mode, so the mercury plasma becomes unstable during the discharge, and as the terminal voltage between the anode and cathode increases, the mercury Energy input increases. This is unfavorable as a switch characteristic, and furthermore, there are problems such as shortening the life of the ignitron and reducing the amount of electricity discharged.

The present invention was made to solve the above-mentioned problems, and aims to provide an ignitron with improved switch characteristics and a longer life.

[Means for solving problems]

The ignitron according to this invention has a
A cylindrical return current conductor and a helical return current conductor whose one end is connected to the end of the cylindrical return current conductor are superimposed.

[Effect]

In this invention, a helical return current conductor causes a return current in the opposite direction to flow outside the vacuum chamber, thereby generating a stabilizing magnetic field in the plasma generation section.

〔Example〕

1 and 2 show essential parts of an embodiment of the present invention, in which a cylindrical return current conductor is shown covering the outer periphery of a cylindrical vacuum chamber 3 housing an anode, a mercury cathode 6, etc. 21
is connected to the cathode terminal and coaxially disposed, and furthermore, a helical return current conductor made of a helical conductor is disposed around the outer periphery of the cylindrical return current conductor. The cylindrical return current conductor 21 and the helical return current conductor 22 are electrically connected at the connection portion 2J at the upper end of each, and are insulated from each other at other portions. The lower end of the helical return current conductor 2 is electrically connected to the lower end of a conductor provided on the outside of the vacuum chamber 3. Other parts are the same as those in FIG.

In the ignitron configured as described above, the current passing from the anode terminal l to the anode λ is positive.

The mercury reaches the mercury cathode 6 through the mercury plasma P or mercury vapor generated between the cathodes. Furthermore, this current is
The current flows from the cathode terminal through the cylindrical return current conductor J in the direction opposite to the direction of the current in the plasma P, and then from the upper end to the lower end of the helical turn current conductor. A magnetic field parallel to the current flowing in the plasma P is generated in the plasma P by the current flowing through the helical return current conductor. The direction of this magnetic field is the same as or opposite to the direction of the current flowing in the plasma P depending on the winding direction of the helical return current conductor 22.

The current flowing through the helical return current conductor is guided to the conductor 1, thus forming a closed circuit that closes like a switch. In FIG. 2, arrows indicate the direction of current.

As described above, since a stabilizing magnetic field is generated by the two helical return current conductors, in terms of magnetohydrodynamics, the plasma P or mercury vapor and the cylindrical return current conductor I are susceptible to external kink instability. satisfies sufficient conditions for stability against Therefore, the extremely dangerous instability of the plasma is eliminated. In addition, internal kink instability can be stabilized by satisfying eight conditions in a stabilizing magnetic field parallel to the plasma current, so the plasma is stabilized, the voltage between the anode and cathode decreases, and energy to the plasma is reduced. The inflow of will decrease. This makes it difficult for mercury to form amalgams with other structural materials, and also reduces heat generation in the ignitron body.

In the above embodiment, the cylindrical return current conductor is a complete cylinder, but appropriate slits are provided in this to create a stabilizing magnetic field inside the ignitron.

It may be possible to make it easier to enter.

Further, the cylindrical return current conductor may be arranged outside the helical return current conductor.

〔Effect of the invention〕

As described above, in this invention, a helical return current conductor is provided to generate a stabilizing magnetic field.
Since the energy flowing into the plasma is reduced, deterioration of the ignition iron is kept to a minimum, extending its life, reducing the voltage between terminals, and improving switching characteristics.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view of a main part of an embodiment of the present invention, FIG. 2 is a vertical cross-sectional view of a main part, and FIG. 3 is a vertical cross-sectional view of a conventional ignitron. Yu...positive i, 3...vacuum chamber, 6...mercury cathode, 21...
A cylindrical return conductor, a Yuko helical return current conductor. In each figure, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] a cylindrical vacuum chamber containing an anode and a mercury cathode; a cylindrical return current conductor whose lower end is connected to the cathode terminal and coaxially arranged around the outer wall of the vacuum chamber; and whose upper end is connected to the cylindrical return current conductor. An ignitron comprising: a helical return current conductor connected to the upper end of the current conductor and arranged in parallel with the cylindrical return current conductor.