US1799580A - Insulator - Google Patents

Description

E. BURKE INSULATOR April 7, 1931.

Filed Feb. 7, 1927 2o and tensile strength 40 tensile strength.

Patented Apr. 7, 1931' UNITED STATES vParraN'r' OFFICE ummm) BURKE, or IPOBTLAND,

MAINE, ASSIGNOB TO BROWN COMPANY, 01' PORT- LAND, MAINE, A CORPORATION OF MAINE INSULATOR Application led February 1 1927. Serial No. 168,538.

My present invention relates to insulators and is of particular limportance in connection with insulators for high tension installation. Such and are of such a fragile nature that they1 are frequently broken 1n shipping and handling or are peculiarly objects of vandalism as by sniping. rlhis all contributes to a w very heavy installation and upkeep cost and to great trouble and annoyance in maintaining eiiciency on the lines. v

It has been proposed to make composition insulators of less expensive material and is some of the smaller and simpler types of insulators have been so produced. The problem, however, oi' producing a suitable insulator for high tension lines and one capable of being produced with suiiicient resistance has not as far as I know been solved. The problem includes that of producing insulator structures of a tensile strength sufficient to withstand many thousand pounds and at the same time being able to withstand the sparking and arcing effects of the highest voltages.l

Considering iirst the material phase of my invention I secure a tensile variant while preserving a substantially homogeneous material in two forms each old in itself and bothv heretofore used together but I use them in a new relation and according to a new concept of their potentialities.

Briey, this aspect of myk invention re lates tothe use of a fibrous material in two forms-both permeable by a dielectric binder but differentiated as to permeability and The combining possibilities give in this art that factor much needed and long sought by which commercial success may be attained. A

In dealing with my other factor (structural) I provide a stem member of general insulators as are at present 5 used for this work are enormously expensive dielectric strength. As herein-v 30 after pointed out I effect this by the use of construction and ca able of being manufactured from such a bre mixture 1n commercial lengths. i

By combining with v'this unitary elements,

` say of the petticoattype, I am able to produce insulators varying' from the single unit type to those o f maximum total distances capable of insulating against the highest voltages.

For convenience of illustrative reference, I

have selected certain well known types of v insulators and have shown in the accompanying drawings embodiments in accordance with an exterior thread and the petticoat units 2 are threaded thereon preferably being pinned as at P by wooden pegs as indicated 1n Fig. 2.

Such an insulator as shown in Fig. 1 may have the usual upper eyed connectionscrewed on to the end of the tube and a lower clevis connection screwed on the other end as indicated at 4. The tubular member. l is preferably filled with a high melting point pitch, as indicated at 5. Any desirable pitch or asphaltic material may be used for this purpose, as for example gilsonite.

.Where the central stem is to be used in the general pin type of insulator I provide as in Fig. 3, a stem l1 threaded as lefore but turned so as to give a butt 12 in which is formed a threaded socket 6 corresponding to the usual construction of such insulators. Such an insulator, I have illustrated in Fig. 3, has its terminal 7 provided with cable notches and grooves 71 and 72, respectively. In the form shown in Fig. 3, the petticoat units 21 are provided with short necks 22 by which the units are spaced from each other.

In Fig. 4 I have shown a convenient structure in the manufacture of stems for insulator purposes. In this drawing I have indicated the tubular stem b 1. This may be a piece of bre tubing which can be produced in stock lengths and sizes. On the end of such a section 1 I slip a short section 10 cut from a tubing having an internal diameter substantially fitting the external diameter of the tube 1. This ring 10 is preferably pinned as at P by wooden pins thus forming on the tube 1 a shoulder for carrying any suitable terminal member as 9 having engaging arms or points 8. The pins P are preferably of wood as such pins are capable of receiving waterproofing and dielectric impregnation.

In such structures it is to be noted that there are two main members, each of which must be of high dielectric strength but when considered as separate elements only one need be of considera le tensile strength.

This apparently has been one of the failures of previous concepts relating to composition insulators. One of thev roblems involved was that of providing su stantial homogeneity throughout the'mass of the material from which the insulator is formed. This is important as a matter of securing high dielectric strength and is also important as a matter of ultimate bonding or consolidationof the separate members so as to secure a substantial unification.

veloped stem member, stem of substantially the same material as the flange or petticoat portions but of a much higher tensile strength and one capable of being turned or threaded or otherwise worked on to get such mechanical assembly as seemed desirable.

I therefore preferably take two classes of the same material, as for example long wood fibre and fine sawdust or Wood flour.' I find it preferable to have these of generally the same origin, although it is stitute fibre of proper length of other origin than a Woody origin, as for example leather bre or even such vegetable bres as cotton. While the wood pulp is preferable for many reasons, there might be adulteration or substitution by the use of infusorial earths, cork finely ground clinkers or a great variety of other materials. I mention these in order that there may be no misunderstanding as to the scope of my invention, but on account of the inexpensive character of woody matters and their general availability, such seem to me at present to be logical materials for commercial roduction.

In preparing such materials I utilize-the t-wo forms `generally as follows. For my Having thereforeA understood the possibilities of a specially defmy concept was of a` possible to substem mixture I use preferably a long strong fibre such as the best quality of s ruce and preferably a selected fibre. Such bre takes a hi h impregnation and when mixed w1th Wood Hour, which is even more easily impregnated, I am able to get a stem mlxture of very great strength. The amount of the long libre used merely depends on the ult1- mate strength of the stem required and the mixture may be infinitely varied from a low percentage of long fibre to an excluslve use of long fibre which makes a material of very great tensile strength. Such a stem is capable of being turned and threaded as indicated 1n the drawings and when producedin tubular form is capable not only of fibre impregnation but of secondary impregnations externally and internally and may then be filled with a fused or melted core of the same dip electric or any variant desired. In making the flange or petticoat members Where the tensile strength is not needed, the fibre may be omitted and the wood flour or like material impregnated or moulded rapidly and shaped.

The insulator is then assembled in its several parts and preferably dipped 1n a moulten bath of high'melting point pitch or mixture. Such a coating not only completes the assembly and unifies the parts, but by reason of its impregnation of all cracks or exposed surfaces resulting from manufacture gives the resultant article a hi h fnlsh, weather resistant surface, and ma es of the assembly a unit of very high electrical resistance.

The stem principle as applied to such structures makes possible a very extended total distance of insulation and makes possible a very ra id assembly of elementary parts into a variety of insulators each when completed constituting substantially a d1- electric entirety.v

The filling as indicated at 5 not only makes possible the use of the tubular stem with all its manufacturin advantages, but actually makes out of t at stem a member of greater insulating value which in itself would be important apart from the strength and economy gained by the use of the tubular principle for the stem.

While applicant has only attempted to show two general types of insulators, it will be understood that most of the usual types and designs of insulators can be made in accordance with my invention and that such variations in design and other variations in details of structure and assembly are all understood to be within the purview of his invention as defined in What I therefore claim and desire to secure by Letters Patent is 1.. In an impregnated insulator, a stem member composed of long wood libre and a comminuted absorbent filler, and a flan e member having a greater amount of said a the appended claims.V

sorbent ller and a lesser amount of long fibre, and a non-conductive core sealed within said stem..

2. In an impregnated insulator, a. stem member composed of lon wood bre and a comminuted absorbent er, and a Han e member having a greater amount of absor ent ller and a lesser amount of said long fibre.

In testimon whereof I ax m si attire.

y EDMUND

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