US2573797A - Switch having one or more tubular contacts - Google Patents

Description

Nov. 6, 1951 A. LATOUR 2,573,797

SWITCH HAVING ONE OR MORE TUBULAR CONTACTS Filed Jan. 25, 1947 3 Sheets-Sheet 1 Fig .1.

Nov. 6, 1951 A. LATOUQR SWITCH HAVING om: OR MORE TUBULAR CONTACTS 3 Sheets-Sheet 2 Filed Jan. 23, 1947 Fig.4.

Nov. 6, 1951 A. LATOUR 2,573,797

SWITCH HAVING ONE OR MORE TUBULAR CONTACTS Filed Jan. 23, 1947 3 Sheets-Sheet 3 Fig.5.

XII v 22 3111 Patented Nov. 6, 1951 SWITCH HAVING ONE OR MORE TUBULAR CONTACTS Andr Latour, Grenoble, France Application January 23, 1947, Serial No. 723,727 In France February 24, 1944 Section 1, Public Law690, August 8, 1946 Patent expires February 24, 1964 6 Claims. 1

The invention relates to switches of the centripetal blast type, having cylindrical contacts, preferably of same external diameter and at least one of which being tubular, in which the arc is driven by the blast towards the center and at the inside of the contact or contacts through which the blast fluid escapes.

An object of my invention is to provide a switch of said type, in which the gas flow is symmetrically distributed about the axis of the contacts, in view to center the arc in the best position to be blown out.

Another object of my invention is to provide a switch of said type in which the volume of extinguishing gas previously exposed to the radiation of the arc is reduced to a minimum compatible with the flow oi the compressed gas, in View to prevent the ionisation and the heating action of the arc, which has for effect to considerably lower the dielectric proportion of the extinguishing gas.

In view of these objects and of other which will appear in the following description, the'main feature of my invention is to provide a screen, the internal form 'of which is substantially cylindrical and which surrounds the cylindrical contacts, leaving an annular space of suitable section forming two paths of flow for the extinguishing fluid,

- in opposite directions, substantially parallel to the axis of the contact, the internal shape of the r internal wall of the screen preferably favoring the change of orientation of the flow just in front of the arc gap.

The invention will moreover be better understood irorn the following description and by reference to the accompanying drawing given purely by way of example in .no Way limit-ative and in which:

Fig. 1 shows a section through the: axis ofJthe deviceaccording to the invention;

Fig. 2 is a section through the of a modification of the invention;

Fig. 3 is a sectionthrough the plane III-III of Fig. 2;

Fig. 4 shows in axial section an embodiment a of the invention applied to multiple break switches;

Fig. 5 is a modification of thissame applica tion;

Fig. 6 is a section on the plane VI -VI of Fig. 5.

On the Fig. 1 both contacts are shown at i and 2 in their open position or practically so. One of the contacts can be stationary and the other movable, or both can be movable. The

screen is shown at 3 andthe whole of the -conits tacts and the screen are placed in a chamber, not shown, in which compressed gas is admitted when a break is to be effected. The compressed liuid penetrates on both sides at 4 and 5 through the annular space left between the screen and the contact-carrying tubes 6 and I. It thus forms two currents in opposite directions 4, 4 and 5, 5 which in contacting each other are, by this very fact, thrown violently back towards the axis of the contacts to be subsequently exhausted through the inside of the tubes 6 and 7. This sudden rejection of the gaseous current towards the axis of the contacts determines in the column or the electric are a state of pressure or turbulenoe particularly favourable to the dielectric regeneration of the ionised medium. Furthermore it will be readily seen that all the compressed fluid situated outside the screen 3, is subjected to the radiation of the arc and conserves, in consequence, thus all the dielectric properties.

It is obviously advantageous to subtract from the radiation of the arc the greatest possible amount of the compressed fluid. For this purpose it is desirable to avoid giving to the screen a too large internal diameter in relation to that of the contacts because, in this case, the radiation of the arc would call for too large an amount or volume of compressed fluid. It is nevertheless necessary that the diameter shall be sufficient so as not to introduce sensible losses in charge due to a too small section ofannular passage. The latter must be at least of the same order as the section of passage of the contact and in practice one may adopt section equal to several times the section of passage of the contact or contacts.

In any case it must be remembered that the volume of compressed fluid subjected to the radiation of the arc is materialized by the solid. of revolution defined by the internal surface of the screen and the common tangents 8- and 9 to the two contacts and that it is desirable to make said'volume as small as the losses in charge will permit on the one hand. and the insulation distances between the screen and'electrodes on the other hand.

In view, to further reduce the value of the extinguishinggas subjected to the radiator the arc, eddies and turbulence are to be avoided in the volume hereinabove defined, where the flow changes from the axial direction to the centripetal direction. With this object in view and in view to further reduce said volume, my invention provides a screen, the internal form of which is a cylinder of revolution, the generatrix of said on the other hand to trace the generatrix giving rise to the internal surface of the screen, over a curve sensibly reproducing the equi-potenti'al move towards the upper part of this figure.

it is for an. apparatus comprising a single break of the screen 3 and the directing elements I l and [2 or part only of these elements, can be applied one against the other by means of a spring 20, preferably housed in an extensible casing 26, 21.

In Fig. fl the movable contact l is shown moving towards the bottom of the figure but it could equally well have been provided at the place of the fixed contact 2 and in such case If element the connecting conduits l9 of the cover curve corresponding to the electric field around the electrode. In this way the gradient of the electric tension on the internal surface of the screen is considerably improved.

To prevent the compressed fluid to .take up turning movement which might give rise to turbulence, the invention foreshadows again the provision of directing vanes which are preferably housed at the extremities of the screen. These arrangements are shown at H and 12 in Fig. 2 and'at-l I in the section shown at Fig. 3.

When the assembly formed by the electrodes l, 2 and the screen 3 is intended as it is generally the case, to be included in a chamber wherein the compressed fluid enters from one end, it may occur that through the diflerent orientation of the inlet orifices to the screen relatively to the arrival of compressed fluid in the chamber, the two opposed currents 4 and 5, shown in Fig. 1 do not have an equal speed. This may give rise to an objection as regards the good distribution of the blowing current especially if the electrodes and the screen have to make a symmetrical system as it isthe case in Fig. 2. To avoid this the invention foreshadows of admitting the compressed fiuid laterally into the screen in such a manner that the orientation of the upper entry in relation to the arrival of fluid under pressure, shall be the same as that of the lower entry. This can be efiected in any appropriate manner and more especially as seen in Fig. 2 by means of a kind of ring l3, l4 held at a suitable distance from the extremity of the screen. This arrangement is advantageous insofar as that it permits of regulating independenty of each other, the

entry sections of the screen and so to obtain equal or differing opposite currents as desired.

One can also, instead of providing lateral entries, keep their axial orientation 'by supplying the one of them whose opening is opposite the entry of fluid into the chamber with a deflecting ring which will deviate the current of fluid by 180, in such a manner that both orifices will thus be directed to the same side.

Fig. 4 shows an example of the invention applied to a multiple break switch. Each break element consists'of a pair of contacts I, 2, surrounded by its screen 3 and its directing member ll, l2 the whole being housed in an insulator l5 forming a chamber to the interior of which the compressed fluid is admitted, for example from the bottom, by means of the annular space It. The insulator I5 is closed at one end by a hood I! provided with orifices l8 for the evacuation of the fluid which has traversed the contacts 2 and 2' and with conduits l9 through which the of the arc spurting between the contacts I and 2. For convenience in mounting the assembly I! are eliminated.

The screen 3 of the preceding figures can also be used asinsulating support fed with compressed fluid by its two extremities. Fig. 5

is an example of a similar arrangement which isapplicable equally well to single break switches as to multiply break switches. In the example shown, the supply of compressed fluid takes place through a single channel 2|. It is necescary in such case to ensure that there shall not result an unequal distribution of blowing current at the interior of the screen. In this case, it is possible, as shown in Fig. 6 which represents a section of Fig. 5 through the plane VIVI, to dispose the directing vanes in a casing 22 the wall of which takes the form of a spiral around the vanes in the manner of a turbine casing. To facilitate the entry of fluid, the extremity of the directing vanes can advantageously be bent back in a suitable direction.

A similar result could be obtained by providing at each entry to the screen, two fluid inlets set at 180 and created either by means of two conduits suitably fitted in the part 23 and which would replace the single conduit 24 of Fig. 6, or by duplicating the channel 2! symmetrically to the axis of the contacts. Although all the figures show the contacts of each break element as symmetrically equal, the invention is in no way limited to this form of construction. In particular one of the contacts can have a larger opening or smaller opening than the other or even not have an orifice at all and then have the form of a solid contact eventually provided with an additional piece of refractory metal on which can engage one of the roots of the arc.

The screen 3 can be made of conducting material (metal or otherwise) and in such a case be totally insulated from the electrodes. It can also be made of refractory insulating material such for example as special porcelain, steatite, zircone and so on. It is more particularly recommended to choose an insulating material having both a good resistance to sudden rises in temperature and good internal and superficial dielectric qualities. It is also possible to make the screen of a tube of insulating material of great solidity mechanically (moulded material, paper or tissue impregnated with a synthetic resin, and so on) covered internally with a material having the desired profile and properties.

The screen can also be made of material of low conductivity and so serve as a resistance in parallel for the break.

When there is used, as shown in Fig. 5 a separate feed tube 25, the latter is preferably made of insulating material; But it can also be made from material of low conductivity and so serve as a resistance or as a support for a resistance.

It is obvious that the invention is in no way limited to the form hereinabove described and that in particular all possible variations as to the relative arrangement and form of the several parts and the conduits for the compressed fluid, must be considered as forming part thereof.

What I claim is:

1. A gas blast switch comprising in combination, two cylindrical coaxial relatively movable contacts, at least one of which is tubular, a member, the internal surface of which is cylindrical and surrounds with play both said contacts to form two annular cylindrical conducts for the compressed gas and means for introducing the compressed gas into said annular conducts.

2. In a gas blast switch, in combination, two axially aligned cylindrical contacts movable relative to each other and each having a contact surface for interengagement, at least one of said contacts being hollow to receive on its interior gases for discharge, and a stationary member surrounding a portion of each of said cylindrical contacts but spaced from the exterior thereof to form therewith oppositely disposed communicating annular cylindrical chambers, one chamber adjacent each contact, each chamber adapted to conduct compressed gas emanating from a blast source to said contact surfaces in a direction opposite to the gas conducting direction of the other chamber.

3. In a gas blast switch, in combination, two axially aligned cylindrical contacts movable relative to each other and each having a contact surface for interengagenient, at least one of said contacts being hollow to receive on its interior gases for discharge, a stationary member sur-- rounding a portion of each of said cylindrical contacts but spaced from the exterior thereof to form therewith oppositely disposed communieating annular cylindrical chambers, one chamber adjacent each contact, each chamber adapted to conduct compressed gas emanating from a blast source to said contact surfaces in a direction opposite to the gas conducting direction of the other chamber, and partition means disposed in said chambers for controlling the flow of gas within the chambers.

4.In a gas blast switch, in combination, two axially aligned cylindrical contacts movable relative to each other and each having a contact surface for interengagement, at least one of said contacts being hollow to receive on its interior gases for discharge and having an orifice concentric with the cylindrical exterior surface, a stationary member surrounding a portion of each of said cylindrical contacts but spaced from the exterior thereof to form therewith oppositely disposed communicating annular cylindrical chambers, one chamber adjacent each contact, each chamber adapted to conduct compressed gas emanating from a blast source to said contact surfaces in a direction opposite to the gas conducting direction of the other chamber, and means associated with said stationary member and projecting into one of said chambers opposite said hollow contact and converging towards the same for directing gases conducted in said one chamber simultaneously axially and radially inwardly for discharge into said orifice.

6 5. In a gas blast switch, in combination, two axially aligned cylindrical contacts, each having an end surface and being movable relative to each other between an interengagement position and another position of disengagement wherein saidend surfaces are spaced for a certain distance, at least one of said contacts being tubular and having an orifice in said end surface to receive gases for subsequent discharge, a stationary member surrounding a portion of each of said cylindrical contacts but spaced from the exterior thereof to form therewith oppositely disposed communicating annular cylindrical chambers, one chamber adjacent each contact, each chamber adapted to conduct compressed gas emanating from a blast source to said contact surfaces in a direction opposite to the gas conducting direction of the other chamber, and partition means disposed in said chambers for controlling the flow of gas within the chambers, the sectional area of each chamber throughout being proportional to the area of said orifice in accordance with a predetermined ratio for controlling the rate of flow of said gases.

6. In a gas blast switch, in combination, a first cylindrical hollow contact; a second cylindrical hollow contact arranged in alignment with and movably with respect to said first contact; end faces forming part of said contacts, respectively, and arranged for contacting each other in the closed position of the switch; a stationary memher having two substantially cylindrical internal surface portions surrounding, respectively, a portion of each of said cylindrical contacts and being spaced apart from same so as to form therewith substantially annular cylindrical chambers; an internally projecting portion forming part of said stationary member and having the innermost ridge thereof arranged flush with said faces of said contacts in closed position of the switch; and means for introducing compressed gas into said cylindrical chambers whereby the gas is deflected from said annular chambers by said ridge toward the space between said faces of said contacts.

ANDRE LATOUR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,067,648 Rehr Jan. 12, 1937 2,333,598 Strom Nov. 2, 1943 2,359,809 Scott, Jr. Oct. 10, 1944 2,452,221 Brock Oct. 26, 1948 2,481,996 Grunewald et a1. Sept. 13, 1949 FOREIGN PATENTS Number Country Date 606,982 Germany Dec. 14, 1934 452,813 Great Britain Aug. 31, 1936 660,740 Germany June 11, 1938 906,498 France May 22, 1945

Images