US2609432A - Flashover indicator - Google Patents

Description

Sept. 2, 1952 K. R. STEEN 2,609,432

FLASHOVER INDICATOR .Filed July 1o, 195o INVENTOR.

KENNETH R STEEN Biff Patented Sept. 2, 1952 'FLAsHovER INDICATOR Kenneth It. Steen, Portland, Orcg., assigner `to the United States of America as represented by the Secretary y'of the Interior ApplicationJuly 10, 1950, Serial No. 172,995 y p '72. claims. (o1. 17m-311) (Granted under the act of March 3, 1883, as

The invention described herein may be manufactured and used by or for the Government of the United States for governmental purposes without the payment to me of any royalty thereon in accordance with the provisions of the act of March 3, 1883, (22 Stat. 625), as amended by the act of April 30, 1928, (45 Stat, Li6?, 35 U. S. C., i946 Ed. Sec. 45).

This invention is concerned with the protection of electric power transmission lines. In particular, it is concerned with means for indicating when a tower or pole supporting transmission line conductors has been subjected to iiashover. It is related to a co-pending application for patent, Serial Number 172,994 iiled by Harold L. Rorden, William E. Scarborough, and Merwin B. Elton.

There are other flashover indicators in the prior art, some of which resemble the present flashover indicator in some aspects of operation. My invention is concerned with improvements over other similar devices, partly in mechanical structure and partly in method of operation.

This flashover indicator is of the type in which operation is accomplished with the release of a signaling device by the ignition of a small charge of explosive powder. The ignition occurs when a high-voltage flashover occurs on the line structure to which the indicator is attached.

A principal object of my present invention is the production of a iiashover indicator that is simple and inexpensive, and which will operate reliably under severe service conditions.

Another object is to produce a iiashover indicator that will operate reliably when infested with vermin such as cocoon-producing larva. Still another object is to provide electrical connections for the flashovcr indicator which will provide reliable operation on either steel or Wood towers of transmission lines.

What `constitutes my present invention is set forth in the following specification with reference to the drawing and succinctly defined in the appended claims.

In the drawing,

Figure 1 is an elevation showing a front view of a preferred embodiment of my invention mounted with appropriate electrical connections on a wood transmission line pole.

Figure 2 is a partly sectional elevation of the same indicator as shown in Figure 1.

Figure 3 is a vertical sectional view of the same indicator as shown in Figure 2, showing the indicator in'position prior to operation; taken along the line 3 3 indicated in Figure 2.

Figure 4 is a horizontal sectional view at the amended April 30, 1928; 370 O. G. 757) 2 elevation indicated by the arrows ll-ll'Figure 3.

Figure is an enlarged illustration of the eX- plosive cartridge shown in operative location in Figures 3 and 4.

In reference to Figure l, a flash indicator case I, made of Bakelite or similar material is supported on a wood pole 2 which supports transmission conductors in the usual way. The iiash indicator case I is supported on pole 2 by an adjustable conducting strap secured by a bolt 4 which holds also a bracket 5, a ashover rod 6 and an adjusting device 1. Elements 5, 6 and I are adapted from the system of lightning grounding on which an application for patent, No. 583,483, has been filed by Harold L. Rorden.

On pole 2, below the indicator I, there is a loop of wire 8 which is connected by a Wire 9 to a terminal II on the side of the indicator. A connection I2, shown in Figure 3 on the back of case l, connects strap 3 to the interior of the indicator.

Hinged at one sidev of case i, near ie bottom, there is an indicating closure I4, reierred to as an indicating drop, of the shape of one-fourth of a circle. On the face I5 of drop I4, a reiiecting surface is Provided to make the drop easily seen at night when illuminated by a spot light. The configuration of drop I4 is such that when the indicator is set prior to an indication, the bottom of case I is closed by the bottom of indicator I4. The drop is shown open in Figure 1.

A wire spring I6 is provided inside the indicator to provide a mechanical force on drop I4 tending to force the drop open.

The drop, under normal conditions, is held in the closed position by an explosive link 22 made of a glass tube containing a charge of powder 23 between the ends of two connecting electrodes 24 and 25. The link 22 is placed in position as shown in Figure 3 in which end 25 of the link rests in a hollow conducting rivet 26 in the back of case I. Rivet 26 is metallically connected to a strip I2 arranged to be in contact with strap 3 when mounted on pole 2.

The front end 24 of cartridge 22 is supported in a hollow conducting rivet 21 connected to Iterminal II. A hole 28 in the face I5 of drop Ill, coaxial with the centers of rivets 26 and 2l er1- gages the body of cartridge 22 when cartridge 22 is in place as shown in Figure 3. Cartridge 22 is placed in position by lifting closure I4 into the closed position shown in Figures 2, 3, and 4 and inserting cartridge 22 through hollow rivet 22 and through hole 28 so the end 25 rests in rivet 26.

Cartridge 22 then, in bending moment, resists the force of spring I6 holding closure I4 in position against the opening force.

When a ashover occurs on pole 2, a potential difference isset up. between strapS and wire' 8 sufcient to'flash over in cartridge 22 between electrodes 24 and 25 exploding powder charge 23.

provided to hold drop I4 up in the closed position rIhe tube of cartridge 22 is shattered by the explosion of powder 23 so the supportformerly from when released, coaxial openings in said case no longer exists. Drop I4 then is opened-by the 1 Fig. 1.

In reference to the co-pending applicationfor.

patent referred to above, the electrical principles of operation therein are identical with 'those in my invention. Cartridge 22 is substantially the same for both devices. The differencefbetween these two inventions is that whereas in the earlier one cartridge -22 was held by metallic clips .which placed cartridge 22 in cantilever. stress; my in vention lsupports the load of closure `I4 in the middle of cartridge 22 between thetwoends 24 and 25 which are both supportedy .against the bending load; A .This tends to prevent mechanical creepage of electrodes 24 and 25 in cartridge 22 and to prevent accidental breakage. It is easier in my invention to insert cartridge 22 when setting the device'. All that is required in myinvention is to lift closure I4 to the closed position and insert vcartridge 22 with a single movement through rivet 21 and hole 28,and into rivet 25. The delicacy of adjusting a metal clip and a metal catch as required in the earlier device'is avoided.

The mechanical arrangement shown in the drawings is one found by experience to be practical and economical. This arrangement, however, is subject to considerable variation. It is obvious; forV example, thatthe hole 28 in drop I4 could be eliminated and that the same result could be accomplished by a projection at the edge of the face I arranged to engage cartridge 22.

and in said drop and an explosive shatterable c c U cartridge insaid coaxial openings in said case force of spring I6 into thev positionL 'showricin' l l and drop, said` cartridge being placed in said openings in double shear to hold said drop normally inclosed position.

2. Ina ilashover indicator the combination of an insulating case, a hinged indicating drop nor- -mallyf held in said case against the force of a spring Vin said case, coaxial openings in said case REFERENCES CITED The following references are of record in the ille of this patent:

c UNITEn STATES PATENTS Number Name Date 2,006,179 Price, et al June 25, 1935 2,018,459 Menger Oct. 22,- 1935 2,138,430 Rudd Nov. 29, 1938 I FOREIGN PATENTS Number Country Date l l888,842 France Sept. 20, 194 3

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