GB2073999A

GB2073999A - A device for use in a glow discharge apparatus

Info

Publication number: GB2073999A
Application number: GB8012334A
Authority: GB
Original assignee: Vmei Lenin
Current assignee: Vmei Lenin
Priority date: 1980-04-15
Filing date: 1980-04-15
Publication date: 1981-10-21
Also published as: FR2481012A1; GB2073999B; ATA194380A; AT369927B; SE450179B; FR2481012B1; CH657224A5; SE8002774L

Abstract

A device, preferably a module, for use in a glow discharge apparatus, comprises an insulating body 1 which is surrounded by a plurality of elements, one of which elements 3 is electrically conductive and, in use, functions as an anode element, a second of which elements 2 is electrically conductive, is spaced apart from said one element 3 and, in use, functions as a cathode element, and at least a third of which elements 4 is electrically conductive and is disposed intermediate the said one element 3 and the said second element 2. The electrically conductive elements 2, 3, 4 are spaced apart from one another so that their adjacent surface portions define passages 5 communicating with the exterior of the device which passages 5 are of substantially uniform width along their length. The device protects the insulating body 1 from contamination when it is in the vicinity of a glow discharge. <IMAGE>

Description

SPECIFICATION A device for use in a glow discharge apparatus This invention relates to a device, which is preferably in the form of a module, for protecting electric insulators from a glow discharge. The device may be utilized, for example, with duct, bearing and auxiliary electric insulators used in the working chambers of installations for thermo-chemical treatment of components in glow discharges.

A component for protecting electric insulators from glow discharges is known, which is used specifically for protecting duct insulators, and consists of an insulating body in front of which are affixed an anode element and a cathode element, respectively connected to the anode and the cathode, and placed in such a way as to form between themselves and the insulating body a shaft like crevice. This crevice has a variable shape and width along its length, determined by the conditions in the working chamber of the installation. The surfaces that form the crevice have significantly different temperatures when the apparatus is used.

The main disadvantages of the known module are the narrow range of pressures over which the insulator is protected, the low break-through voltage, the difficulty in producing its components and the need for forced cooling.

An object of this invention is to provide a device for protecting electric insulators from glow discharges, which works effectively within a wide range of pressures with high breakthrough voltages, simplified construction and without forced cooling.

According to the present invention there is provided a device for use in a glow discharge apparatus, which device comprises an insulating body which is surrounded or encapsulated by a plurality of elements, one of which elements is electrically conductive and, in use, functions as an anode element; a second of which elements is electrically conductive, is spaced apart from said one element and, in use, functions as a cathode element; and a third of which elements is electrically conductive and is disposed intermediate the said one element and the said second element; wherein the electrically conductive elements are spaced apart from one another so that their adjacent surface portions define passages communicating with the exterior of the device, which passages are of substantially uniform width along their length.

In another aspect, the invention provides a device for protecting an electric insulator from a flow discharge, which comprises an insulating body in front of which are affixed an anode element and a cathode element, wherein (a) the insulator is a body consisting of one or more parts; (b) between the cathode element and the anode element and the insulating body there is at least one intermediate current-conductive element; and (c) the surface configurations of adjacent portions of the device are such that, between the intermediate currentconductive element(s), the cathode element, the anode element and the insulating body there are formed passages open to the exterior of the device which passages are of uniform width along their length.

Preferably, the said passages open to the exterior of the device in the form of slits. The pssages are advantageously maze-like or castellated.

In one embodiment of the invention, one of the said passages is bounded by surface portions of the insulating body, the anode element and the or an intermediate current-conductive element, and another of the said passages is bounded by surface portions of the insulating body, the cathode element and the or another intermediate current-conductive element. There can be two or more electrically conductive elements intermediate the cathode and anode elements; in this arrangement, there will be further passages bounded by surface portions of the insulating body and of the intermediate elements.

The device is preferably in the form of a module.

Conveniently, the device is generally cylindrical and the said elements are disposed about the insulating body as a series of cylindrical annuli of substantially the same external diameter and spaced axially with respect to one another.

The electrically conductive intermediate elements are insulated from their adjacent elements. The width of the passages is selected in accordance with the working conditions in the chamber of the glow discharge installation.

The main advantages of a module in accordance with the invention are that it works with wider range of pressures, has high breakthrough voltage and simplified construction, without needing forced cooling; it has high reliability and universal appiicability, for example, for duct, bearing and auxiliary insulators.

For a better understanding of the invention, and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 is a side elevation, partly in section, of a module, for a duct insulator, with two intermediate current-conducting elements; Figure 2 is a side elevation, partly in section, of a module for a bearing insulator; Figure 3 is a side elevation, partly in section, of the module for an axuiliary insulator; Figure 4 is a side elevation, partly in section, through part of a working chamber of a glow discharge installation which incorporates the modules of Figures 1 and 2.

Referring to the drawings, the device includes an insulating body 1, consisting of three parts. Around this are affixed a cathode element 2, connected to the cathode of the glow discharge installation, an anode element 3, connected to the anode thereof, and between these are placed two intermediate current-conducting elements 4, which are electrically insulated by the different parts of the insulating body 1. The surfaces of the anode element 3 and the cathode element 2 and the intermediate currentconducting elements 4 have a configuration such that between themselves, and between them and the insulating body 1, maze-like openings or passages 5 are formed. All the passages 5 are of the same width, and they have equal width along their length, which width is selected in accordance with the conditions in the working chamber of the glow discharge installation.

Variants for use with a bearing insulator are possible, which has a single intermediate currentconducting element 4 (see Figures 2 and 3).

In Figure 4 are shown variants for application of the module with a single intermediate currentconducting element 4for duct and bearing insulators, installed in the working chamber of an installation for thermo-chemical treatment of components in a glow discharge.

The number of intermediate current-conducting elements 4 is selected on the basis of the working voltage of the electric insulator and the working range of the pressures in the working chamber of the installation. In the case with two intermediate current-conducting elements 4, three maze openings 5 are formed with width selected in accordance with the working conditions of the installation's chamber.

Under the conditions of glow discharge in the working chamber, due to the maze shape of the openings 5the penetration of,current-conducting particles in the opening is prevented and thus the surfaces of the insulating body are saved from contamination.

Claims

1. A device for protecting an electric insulator from a glow discharge, which comprises an insulating body in front of which are affixed an anode element and a cathode element, wherein (a) the insulator is a body consisting of one or more parts; (b) between the cathode element and the anode element and the insulating body there is at least one intermediate current-conductive element; and (c) the surface configurations of adjacent portions of the device are such that, between the intermediate current-conductive element(s), the cathode element, the anode element and the insulating body there are formed passages open to the exterior of the device which passages are of uniform width along their length.

2. A device for use in a glow discharge apparatus, which device comprises an insulating body which is surrounded or encapsulated by a plurality of elements, one of which elements is electrically conductive and, in use, functions as an anode element, a second of which elements is electrically conductive, is spaced apart from said one element and, in use, functions as a cathode element; and a third of which elements is electrically conductive and is disposed intermediate the said one element and the said second element; wherein the electrically conductive elements are spaced apart from one another so that their adjacent surface portions define passages communicating with the exterior of the device, which passages are of substantially uniform width along their length.

3. A device as claimed in claim 1 or 2, wherein the said passages open to the exterior of the device in the form of slits.

4. A device as claimed in claim 1, 2 or 3, wherein the said passages are maze-like in nature.

5. A device as claimed in claim 1,2,3 or 4, wherein one of the said passages is bounded by surface portions of the insulating body, the anode element and the or an intermediate currentconductive element, and another of the said passages is bounded by surface portions of the insulating body, the cathode element and the or another intermediate current-conductive element.

6. A device as claimed in claim 5, wherein there are two intermediate current conductive elements, and wherein a third one of the said passages is bounded by surface portions of the insulating body and of the two intermediate current-conductive elements.

7. A device as claimed in any preceding claim, in modular form.

8. A device as claimed in claim 2, wherein there are two electrically conductive elements intermediate the said one element and the said second element.

9. A device as claimed in claim 2 or 8, wherein the device is generally cylindrical and the said elements are disposed about the insulating body as a series of cylindrical annuli of substantially the same external diameter and spaced axially with respect to one another.

10. A device as claimed in claim 9, wherein each of the passages between adjacent elements is castellated in appearance when viewed in crosssection through the cylindrical axis of the device.

11. A device as claimed in any preceding claim, wherein the insulating body comprises two or more parts.

12. A device, for use in a glow discharge apparatus substantially as hereinbefore described wih reference to, and as illustrated in, Figure 1 of the accompanying drawings.

13. A device, for use in a glow discharge apparatus. substantially as hereinbefore described with reference to, and as illustrated in, Figure 2 of the accompanying drawings.

14. A device, for use in a glow discharge apparatus, substantially as hereinbefore described wih reference to, and as illustrated in, Figure 3 of the accompanying drawings.

15. . A glow discharge apparatus which includes a device as claimed in any preceding claim.

16. A glow discharge apparatus substantially as hereinbefore described with reference to, and as illustrated in, Figure 4 of the accompanying drawings.