US1199467A - Iron-porcelain insulating-bushing. - Google Patents

Description

R. P. JACKSON.

IRON PORCELAIN INSULATlNG BUSHlNG.

APPLICATON FILED )UNE 9 1914. 1,199,467.

Patented Sept. 26, 1916.

INVENTOR d/ ADJaC/fa/z ATTNEY WITNESS'S: y f La/23M j@ d 7 UNITED STATES PATENT OFFICE.

RAY P. JACKSON, 0F EDGEWOOD PARK, PENNSYLVANIA, ASSIGNOR TO TESTING-HOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

v IRON -PORCELAIN INSULATING-BUSHING.

Specification of Letters Patent. Patented Slept. 26, 1916,

Application filed .Tune 9, 1914. Serial No. 843,948.

l To all 'whom it may concern:

Be it known that I, RAY P. JACKSON, a citizen of the United States, and a resident of Edgewood Park, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Iron-Porcelain Insulating-Bushings, of Which the following is a specification.

My invention relates to electrical insulating structures, and it refers to bushings which are adapted to insulate high-potential conductors from walls of casings or tanks in which transformers or other electric apparatus associated with the high-potential conductors may be disposed. However', it will be understood that my invention may be utilized also in high-voltage outlet structures for power stations, transformer sub-stations, etc., where it is necessary to bring high-potential transmission conductors through the walls or roofs of the sta.-` tion building.

The usual porcelain insulating bushings l which have corrugated surfaces or a plu.- rality of superposed petticoats are liable to be broken when located in places where they are exposed to severe mechanical shocks and strains. To insure them a ainst breakage, porcelain insulators are o a cumbersome construction in order to provide suiiicient strength to resist the strains imposed upon them. As 'a result, the weight of such insulators makes them dilicult to handle, and increases their cost of construction. By means of my invention, vI provide an insulating bushing which is particularly adapted for severe service conditions, because the eX- posed petticoats are made of cast iron or some other material which is capable of withstanding very severe mechanical shocks and strains. Furthermore,l my insulating bushing may be utilized to insulate very high-voltage conductors and, at the same time, be smaller in size and simpler in construction than insulating bushings of the usual porcelain type heretofore constructed for similar service conditions.

For a better understanding of the nature and the scope of my invention, reference may be had to the following description andthe accompanying drawing in which- Figure 1 is a cross sectional view of an insulating bushing constructed in accordance with my invention, and Fig. 2 is a cross sectional view showing a conductor threaded through a condenser-type bushing which, in turn, is embraced by a bushing embodying a form of my invention.

Referring to Fig. 1, a high-potential conductor 2 is embraced by a bushing 3 which comprises a continuous inner tube 4i surthe rod 2 and the transmission conductor or othervapparatus (not showin) is effected by,

mears of any suitable means engaging the cap The portions of the bushing 3 which are exposed to mechanical shocks constitute a series of superposed metallic conducting members or petticoats 8 made of cast iron or other suitable material. The edge of the opening in each petticoat merges intoa bead 9 which engages the insulating cylinders 5 at their mid points or elbows l0. With the exception of the uppermost petticoat 8, each petticoat is interposed between two adjacent and superposed cylinders 5, and is maintained rigidly in position by means of Portland cement 11 which adheres to the metallic petticoat Sand the adjacent surfaces of the cylinders 5. Bridging the spaces between ,adjacent petticoats 8, are bodies 12 of insulating material which is capable of being molded and has high dielectric strength, suc'h as an insulating gum of a variety well known in the art. For maximum efficiency, the material l2 between each adjacent pair of the metal petticoats 8 is so molded as to provide a leakage surface therebetween which conforms to the direction of the elecinverted substantially frusto-conical shapes,

engage the exposed surfaces of the molded material. It will be understood that it is not essential to have the exposed insulating surfaces conform to the direction of the electrostatic flow lines representing the electric field between the conducting members, but, in high-voltage installations, it is desirable to design the insulating bushings in accordance with this principle in order to obtain the maximum insulating strength of the bushing.'

In constructing the bushing, the adjacent porcelain cylinders 5 are built up, and insulating gum 14 is interposed between adjacent surfaces of the upper half of the lower cylinder, and the lower halfy ofthe upper cylinder. The space between the rod 2 and the inner tube 4 may be likewise filled with a suitable insulating gum.

It is apparent that it will be necessary to supply each bushing with a plurality of conducting petticoats 8, insulated from one another by means of the nested porcelain insulators 5, the total number of conducting members for each bushing depending upon the service conditions to which the bushing is -to be subjected. The conducting members 8 are adequately insulated from one another, and the porcelain members 13 are interposed therebetween to provide permanent leakage paths of high resistance. The petticoats 8 extend laterally beyond the members 13, thereby shielding them from rain and mechanical blows which would either decrease or deteriorate their insulating qualities, or lessen 'the .resistance of the leakage paths. Again, the porcelain cylinders 5 are subjected only to compressive stresses which porcelain is particularly adapted to resist.

lVhile I have shown porcelain members 13 engaging the exposed surfaces of the insulating material 12, it is not necessary that these porcelain members be supplied. However, it is preferable to protect the exposed surfaces of the molded material 12, inasmuch as it may become honeycombed and filled with particles of dust and other matters which will decrease its insulating properties. Asa result, the resistance of the leakage path between the adjacent petticoats S will be decreased unless the porcelain members 13 are utilized to protect the exposed surfaces of the insulating material 12. Again, porcelain material may be readily molded into various shapes before being glazed. This property particularly adapts porcelain for use where the exposed insulating surface should conform to electrostatic iiow lines, as mentioned above.

Referring to Fig. 2, an inner bushing 15 of the condenser type of construction, which comprises a plurality of layers of alternately insulating and conducting materials, .embraces a metallic tube 16 which constitutes the high-potential conductor. The exposed portion of the bushing l5 is inclosed by a bushing built in accordance with my invention. The frusto-conical end of the condenser bushing is hermetically sealed in position within the bushing 3 by means of an insulating gum or compound 17. Inasmuch as the electrostatic stresses are equalized and the electrostatic lines are uniformly distributed by reason of the bushing 15, the porcelain members 13 which constitute the leakage paths between adjacent petticoats 8, are of similar form and shape throughout the length of the built-up structure. In other respects, the exterior bushing shown in Fig. 2 corresponds to the bushing of Fig. 1, which yis fully described above.

My invention is, of course, not restricted to any particular application, and I desire that the scope shall be limited only by the appended claims.

I claim as my invention:

1. An insulating structure comprising a series of superposed and telescoped insulating tubular members to provide double walls, a plurality of laterally extending annular conducting members, the inner rim of each being interposed between adjacent pairs of said insulating members, and additional insulating bodies bridging the spaces between the, said adjacent conducting members.

2. An insulating structure comprising a series of superposed insulating tubular members, the lower portion of each overlapping with the upper portion of the next succeeding one to provide double walls, a plurality of annular conducting members having their inner rims interposed between adjacent pairs of said insulating members, and additional insulating bodies bridging the spaces between the adjacent conducting members, and being shaped to substantially conform to the electrostatic flow lines extending between adjacent conducting members.

3. An insulating bushing comprising a series of superposed insulating tubular members having elbows formed intermediate]` their ends, a plurality of annular conducting members engaging the tubular members at said elbows, and insulating ybodies bridging the spaces between adjacent conducting members, said conducting members extending laterally beyond the insulating material.

4. An insulating bushing comprising a series of superposed and telescoped insulating tubular members having elbows formed intermediate their ends, a plurality of laterally and downwardly extending annular conducting members engaging said elbows of the insulating members, and insulating material so shaped as to conform to the electrostatic How lines bridging the spaces between adjacent conducting members.

5. An insulating bushing comprising a series of superposed insulating cylinders tending laterally beyond the `porcelain 10 having elbows formed intermediate their members.

ends, a plurality of annular conducting In testimony whereof, I have hereunto members engaging the cylinders at said subscribed my name this 22nd day of May, elbows, and additional porcelain members 1914.

bridging the spaces between adjacent con- RAY P. JACKSON. ductingy members in order to providel leak- Witnesses: A

a ge paths therebetween of permanently high V. K. WILLIAMS,

resistance, the said conducting members eX- B. Bv

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