US2306527A - Electric-power transmission system - Google Patents

Description

H. C. DANIELS ELECTRIC-POWER TRANsM1ss1oN-sYsTEMs Dec. 29, 1942.

3 Sheets-Sheet l Filed May 'I 2 1940 NN 5mm .Vm mm mm Dec. 29,v 1942.

H. C. DANIELS ELECTRIC-POWER TRANSMISSION-SYSTEMS Filed May 2, 1940 3 Sheets-Sheet 2 Dec. 2.29,` 1942.-, H. c. DANN-:Ls

ELECTRIC-POWER TRANSMISSION-SYSTEMS Filed May 2, 1940 3 Sheets-Sheet 5 4 Patented Dec. Z9, 1942 ELECTRIC-POWER TRANSMISSION SYSTEM Harold C. Daniels, Woodbury, Conn., assignor to Chase Brass & Co Waterbury, Conn., a c

pper Co. Incorporated, orporation Application May 2, 1940, Serial No. 332,943

2 Claims.

The present invention relates to improvements in electric-power transmission-systems and relates more particularly to electric transmissionmeans for the transmission of electrical power of commercial frequencies and voltages.

More specifically the present invention relates to electric-power transmission-systems of the character wherein it is necessary for practical purposes to provide for the circulation of a cooling medium in order to avoid overheating of the elements of the system.

One of the objects of the present invention is to provide a superior electric-power transmissionsystem embodying low cost for manufacture with eciency of service.

Another object of the present invention is to provide an electric-power transmission-system in which a fluid-cooling medium may be economically circulated in such manner as to carry oi the undesired heat in an efficient and effective manner.

Still another object of the present invention is to provide a superior .electric-power transmission-system combining maximum electric-power transmission capacity with minimum space requirements.

A still further object of the present invention is to provide a superior electric-power transmission-system in which a cooling-fluid may be .effectively circulated at low power-cost.

With the above and other objects in View, as will appear to those skilled in the art from the present disclosure, this invention includes all features in the said disclosure which are novel over the prior art.

In the accompanying drawings, in which certain modes of carrying out the present invention are shown for illustrative purposes:

Fig. la is a schematic View partly in vertical central-longitudinal section and partly in side elevation of the left portion of an electric-power transmission-system embodying the present invention; p

Fig. lby is a similar View of the intermediate portion of the transmission-system;

Fig. 1c is a similar view of the right portion thereof;

Fig. 2 is a transverse sectional view taken on the line 2-2 of Fig. 1a but on a larger scale.

Fig. 3 is a broken view partly in side elevation and partly in central-longitudinal section taken on the line 3-3 of Fig. 2;

Fig. 4 is a transverse sectional view taken on the line 4-4 of Fig. 1b but on a larger scale;

Fig. 5 is a broken View partly in side elevation and partly in vertical central-longitudinal section taken on the line 5-5 of Fig. 4;

Fig. 6 is a fragmental View in vertical central-longitudinal section showing the rigid joints between individual sections of the tubular sheath scale;

Fig. 8 is a fragmental view mainly in vertical central-longitudinal section and partly in side elevation of the portion of the system within the dotted line 8 of Fig. 1bI but on a larger scale;

Fig. 9 is a transverse sectional view taken on the line 9-9 of Fig. 8;

Fig. 10 is a perspective view of one of the conductor-supporting spiders or frames; and

Fig. 11 is a perspective View of one of the conductor-clamping caps` The electric-power transmission-system herein chosen for the purpose of illustrating the present invention includes two longitudinally-spacedapart fluid-chambers 20 and 2| of rectangular form and connected together by a tubular sheath generally designated by the reference character 22 but which comprises several coaxial sections arranged end-to-end as will be more fully hereinafter described. The said sheath 22 is fluidtight and is preferably formed of copper 0r the like not only to resist corrosion but also to provide an eflcient thermal conductor for the dissipation ci heat and an eiicient electric-conductor as well.

Extending longitudinally through the sheath 22 and into both of the fluid-chambers 20 and 2| are three (more or less) hollow tubular electric- conductors 23, 24 and 25. The said electricconductors are preferably formed of copper or Vother high electro-conductive material and extend in parallelism with each other in spacedapart relationship both with respect to each other and with respect to the interior surfaces of the sheath 22. The hollow tubular electricconductors such as 23, 24 and 25, and whatever their number, will always occupy but a part of the total cross-sectional area of the sheath 22 so as to provide a huid-passage within the said sheath and exteriorly of the said electricconductors. In other Words, the cross-sectional area of the electric-conductor or electric-conductors within the sheath 22 or its equivalent will jointly and severally have a cross-sectional area less than the cross-sectional area of the interior of the said sheath 22.

The electric-conductor 23 has brazed or other wise secured to its upper surface, two similar conducting-straps 26-26 located in the iluidchamber 20 about midway the length thereof. The upper portions of each of the conductingstraps 26-26 extend into both mechanical and electrical .engagement with the lower portion of the adjacent one of two vertical conducting-rods 27-2'1 each extending upwardly through one of two similar insulators 28-28 mounted upon theupper surface of the fluid-chamber 20 and extending through the top wall thereof as is shown especially well in Fig. la. The upper ends of the conducting-rods 2'|--2'| project upwardly beyond the upper surfaces of the respective insulators 28-28 and may be connected to a linewire or to any desired electrical apparatus.

The outer side-face of the hollow tubular conducor 24 has two conducting-straps 29-29 brazed or otherwise secured to it at two spaced-apart points within the fluid chamber 2|] and adjacent the point of connection of the sheath 22 therewith. Each conducting-strap 29--29 just referred to is connected at its upper end to the lower end of the adjacent one of two Vertical conducting-rods 30-30 each of which is mounted in one of two corresponding insulators 3|3| mounted upon and in part extending downwardly through the top-wall of the huid-chamber 2|). The respective upper ends of the conducting-rods 3&3-30 extend upwardly beyond their respective insulators 3|-3Iv for joint connection to a linewire or any desired electrical apparatus.

Adjacent the outer end of the uid-charnber 2l) the hollow tubular electric-conductor 25 has brazed or otherwise secured to it at longitudinally-spaced-apart points two conducting-straps 32-32 each of which extends upwardly into electrical engagement with the lower portion of the adjacent one of two Vertical conducting-rods 33-33. Each of the conducting-rods 33-33 is mounted in one of two similar insulators 34-34 which are mounted upon the upper wall of the fluid-chamber 20 and extend from the interior to the exterior thereof as do also the conductingrods 33-33.

Adjacent their opposite ends, i. e., the ends within the right :duid-chamber 2|, the three hollow tubular electric- conductors 23, 24 and 25 are also provided with electrical connections leading from the said electric-conductors outwardly to the exterior of the fluid-chamber 2| in a manner similar to that described in connection with the opposite or left end of the said electricconductors.

About midway of the length of its portion extending within the fluid-chamber 2| the hollow tubular electric-conductor 23 has brazed or otherwise secured to it at spaced-apart points two conducting-straps 35-35 each of which extends into electrical engagement with the lower end of one of two vertical conducting-bars 3B3|. Each of the said conducting-bars 36-36 extends from the interior to the exterior of the fluid-chamber 2| through the upper wall thereof and is mounted in one of two similar insulators 31-37 secured to the said upper wall and extending downwardly therethrough.

Adjacent its outer end the hollow tubular electric-conductor 24 has brazed or otherwise secured to it at longitudinally-spaced-apart points two conducting-straps 38--38 each of which extends upwardly into electrical connection with one of two vertical conducting-bars 39-39 both of which extend from the interior to the exterior of the Huid-chamber 2|. Each of the said conductingbars 39-39 is mounted in one of two insulators 4U-4 mounted upon the upper wall of the duid-chamber 2| and extending partly within the interior of the said fluid-chamber.

The portion of the hollow tubular electricconductor 25 within the fluid-chamber 2| has brazed or otherwise connected to it at spacedapart points adjacent the inner wall of the said fluid-chamber, one of two conducting-straps li-4|. The upper end of each of the conducting-straps 42-42 is electrically joined to the lower end of one of two similar vertical conductingrods 42-42 extending from the interior to the exterior of the said fluid-chamber 2 Each conducting-rod 42-42 is mounted in one of two insulators 43-43 carried on the upper wall of the said fluid-chamber.

The sheath 22 is preferably formed of sections of copper tubing joined together in end-to-end relationship in any suitable manner to afford the desired total length of sheath. Over some of the joints between its abutting sections the said sheath has applied to its exterior a couplingband 44 as is especially well shown in Figs. lb and 6. The said coupling-bands are preferably brazed to each of the adjacent sections of the sheath 22 so as to, in eiect, unite the said sections into a rigid unit.

The hollow tubular sheath 22 has its let end rigidly coupled to the adjacent or inner endwall of the fluid-chamber 20 by means of a coupling-flange 45 of L-shaped form in cross-section and having one leg brazed or otherwise rigidly secured to the adjacent portion of the sheath 22 and having its other or radial leg bolted or otherwise secured to the inner end-wall of the iluidchamber 2! as is shown in Fig. la.

At suitable intervals intermediate its respective opposite ends the tubular sheath 22 is anchored against longitudinal movement and supported against downward movement as is shown in the central portion of Fig. 1b and also in Figs. 4 and 5. For the purpose just described the sheath 22 has brazed or otherwise secured upon its periphery an annular coupling-flange 46 of L-shaped form in cross section and having the lower portion of its radial leg coupled to a supporting-bracket 41 mounted upon a supportingblock 48 of concrete or other suitable material.

The right end of the tubular sheath 22 is provided with a coupling-flange 49 brazed or otherwise secured theretoand in turn bolted or otherwise secured to the adjacent inner end-wall of the right fluid-chamber 2|.

Inasmuch as the opposite ends of the sheath 22 are rigidly coupled respectively to the fluidchambers 2B and 2| and the said sheath is held rigidly intermediate of its length upon the supporting-block 48, provision is made for allowing the necessary axial or lengthwise expansion and contraction of the sheath 22 to take place without damage to the structure. The expansion just referred to is provided for by interrupting the sheath 22 with suitable expansion-joints such as those indicated by the reference character 50. The expansion-joints 50 are of known construction and require no detailed description herein other than to say that they provide a fluid-tight joint between adjacent sections of the sheath 22 while still permitting the said sections to move axially with respect to each other.

The hollow tubular electric- conductors 23, 24 and 25 are supported within the sheath 22 and held in spaced relationship with respect to the inner surface of the said sheath and with respect to each other by a series of similar conductorsupporting spiders or frames 5I. Each of the spiders or frames. 5| just referred to is provided with three equidistant and outwardly-facing semicircular seats 52 each of which receives one of three adjacent insulating-tubes 53 one of which surrounds the adjacent portion of each of the said tubular electric- conductors 23, 24 and 25.

Secured to each of the three faces of each spider or frame is a conductor-retaining cap 54 extending over the outer face of the adjacentinsulating-tube 53 and rmly clamping the same in the complemental one of the seats 52 in the spider 5| in such manner that the said insulating-tube is held against axial movement with respect to the said spider. The lit of the insulating-tubes 53 upon the periphery of the respective tubular electric- conductors 23, 24 and 25 is such as to permit the said electric-conductors to slide through the said insulating-tubes without undue hindrance in order to compensate for expansion and contraction lengthwise of the said electric-conductors, save at special points as will hereinafter appear.

The outer portion of each of the three conductor-retaining caps 54 of each spider or frame 5| snugly engages the inner periphery of a spacing-ring 55. Save in special instances hereinafter mentioned each spacing-ring 55 snugly but slidably fits the inner periphery of the sheath 22. Substantially-radial screws 55 are employed for coupling each spacing-ring 55 to each of the adjacent set of three caps 54 and hence also to the adjacent spider or frame 5|.

All but a minor number of the plurality of spacing-rings 55 are free to slide within the sheath 22 in a direction lengthwise thereof. In the construction shown the three spacing-rings designated 55a, 55h, 55e and respectively adjacent the inner end-wall of the fluid-chamber 25, adjacent the supporting-block 48 and adjacent the inner end-wall of the fluid-chamber 2| are held against sliding movement within the sheath 22 by screws 57. It follows from the foregoing that the three spiders or frames 5| associated with the three spacing-rings 55a, 5517 and 55o are also held against axial movement with respect to the sheath 22.

For the purpose of anchoring each of the tubular electric- conductors 23, 24 and 25 against axial movement within such of their respective insulating sleeves 53 as are coupled to the aforesaid spacing-rings 55a, 555 and 55e, stop-collars 58 are employed. One of the stop-collars 58 is mounted in engagement with each of the respective opposite ends of each of the insulating-tubes 53 encompassed by the said spacing-rings 55a, 5517 and 55e and the said stop-collars 58 are rigidly attached to the adjacent portions of Whichever one of the electric- conductors 23, 24 or 25 may extend therethrough.

The stop-collars 58 above referred to are preferably made of metal and inasmuch as they in effect reduce the gap between the respective tubular electric- conductors 23, 24 and 25, it is preferable that each of the said collars be covered with a mass of insulating material 59.

To permit the hollow tubular electric- conductors 23, 24 and 25 to expand and contract lengthwise in response to temperature changes, each of the said electric-conductors hasinterposed in it at spaced-apart points intermediate its points of anchorage as above described, a series of corresponding expansion-joints generally designated by the reference character 60 and especially well shown in Figs. 8 and 9. Each of the said expansion-joints includes two spaced-apart tubular heads (5I- 6| brazed or sweat-soldered to the adjacent portions of the particular-tubular electric- conductors 23, 24, or 25 of which it forms a feature. The heads 6|-5I are electrically connected together by two or more layers of helically-inclined wires 62 preferably formed of soft copper or other suitable high electroconductive material. Sleeved over each expansion-joint 65 and the adjacent portions of the tubular electric- conductors 23, 24 or 25 of which it forms a feature, is a sealing-tube 53 preferably formed of insulating material. Each of the said sealing-tubes is anchored by any suitable means such as screws 64 to one portion of the particular electric-conductor with which it is assembled and has sliding engagement with the portion of the conductor on the other side of the particular expansion-joint 55, as is especially well shown in Fig. 8. The sealing-tubes 53 serve to minimize the leakage of fluid between the hollow interior of each of the conductors 23, 24 and 25 and the space within the sheath 22 and exterior of the said conductors for purposes as will hereinafter appear, though it is not essential that leakage be more than minimized.

The portions of each of the hollow tubular electric- conductors 23, 24 and 25 which extend within the fluid-chambers 20 and 2| are also equipped and held in spaced relationship by spiders or frames 5| before described, together with their respective spacing-rings 55 and other features described, save that at these locations the said spacing-rings 55 instead of bearing within the interior of the sheath 22 are supported by suitable brackets such as 65.

For the purpose of preventing undue shifting of the various conduit-supporting spiders or frames 5| lengthwise of the sheath 22, it is preferred that the said spiders be interconnected by suitable tie-rods 65.

At their respective left ends the three hollow tubular electric- conductors 23, 24 and 25 do not open directly into the interior of the fluid-chamber 20, but are respectively sleeved-over one of a corresponding number of tubular bosses 6'! projecting inwardly from a header 58 through the outer end-wall of the fluid-chamber 20 and into the interior thereof. The said header 68 is connected by suitable piping 59 to the outlet end of a Huid-circulating pump 10. The inlet end of the said pump 'I0 is connected by suitable piping 1| to one end of a heat-exchanger 'I2 of any suitable character and serving to cool such fluid as may be caused to pass therethrough in the usual manner of heat-exchangers. The opposite end of the heat-exchanger 'I2 is connected by suitable piping 'I3 to the interior of the fluid-chamber 25 as is shown in Fig. 1a.

The respective right ends of the three hollow tubular electric- conductors 23, 24 and 25 open into the interior of the fluid-chamber 2| adjacent the outer end thereof, as is shown especially well in Fig. 1c. Preferably an expansion-tank 'I4 is employed to provide for the expansion and contraction of the fluid contained in the system, and also to provide a reservoir of fluid to automatically replace such fluid as may leak from the system. Preferably the expansion-tank 'I4 is placed at a higher elevation than the highest portionof the system and is connected by suitable piping I5 to the outer end of the fluid-chamber 2|, as shown in Fig. 1c.

When the hollow tubular electric- conductors 23, 24 and 25 or their equivalent have a considerable length between expansion-joints 50, it is desirable to braze or otherwise secure several sections vof tubing together in end-to-end relationship. As shown in the drawings, sections of tubing composing the various hollow tubular electric- conductors 23, 24 and 25 have adjacent ends shaped to provide intertting male and female portions respectively, as shown at l5 in the drawings.

It is preferred that before the system is put into operation that it be filled with a suitable cooling-fluid having insulating properties. Many uids are suitable for the purpose, among which may be mentioned non-inflammable oils such for instance as those on the market under the trade names Pyranol and Inerteen, high flash-point heavy cylinder-oils, transformer oils, carbon tetrachloride, etc., etc. It is preferred that the fluid in the system be maintained at high pressures in order to accentuate the insulating properties of the fluid, and such pressure may be in the order of several hundred pounds per square inch.

After the system including the fluid-chambers 20 and 2 l, the interior of the sheath 22, the interiors of the various hollow tubular electric- conductors 23, 24, 25, the various piping and at least a portion of the expansion-tank 'I4 have been suitably filled with a suitable cooling and insulating fluid, the pump 1U will be driven by any suitable prime-mover.

The starting of the pump l will cause an inflow of the fluid from the header 58 into the left ends of the respective hollow tubular electric- conductors 23, 24 and 25 for flow from left to right throughout the length of the said conductors. The fluid will emerge through the right ends of the electric- conductors 23, 24 and 25 into the outer end of the right fluid-chamber 2| and will then reverse its direction and circulate from right to left through the said fluid-chamber around the exteriors of the respective electric- conductors 23, 24 and 25.

After having flowed from right to left within the fluid-chamber 2| and over the exterior of the hollow tubular electric- conductors 23, 24 and 25, the cooling and insulating fluid will enter the adjacent right end of the tubular sheath 22 and iiow therethrough around the exterior of the said electric-conductors back into the inner end of the left fluid-chamber 25. It is to be borne in mind, in this connection, that the skeletonized nature of the conductor-supporting spiders or frames 5l and their associated parts permits the passage of fluid through the said sheath exteriorly of the hollow electric- conductors 23, 24 and 25.

Alter having emerged into the inner end of the fluid-chamber 20 from the left end of the sheath 22, the cooling and insulating fluid will be drawn through the piping 13 into the heatexchanger 'l2 where the said fluid will be cooled.

The cooled fluid will emerge from the heatexchanger 12 and pass through the piping ll to the pump l0 and again will enter the interiors of all three of the hollow tubular electric- conductors 23, 24 and 25 for another cycle of circulation through the system.

Despite possible heavy pressures existing within the system, the load imposed upon the pum-p "at or its equivalent in circulating the cooling and insulating fluid will amount to substantially only frictional losses.

By providing an electric-power transmissionsystemv such as has been above described, a free and effective flow of cooling iiuid is provided both interiorly and exteriorly of the conductors 23, 24 and 25y or their equivalent without requiring external piping. It is possible by means of the present system to maintain the conductivity of the conductors at maximum efficiency by the effective cooling provided for as above described.

By the reverse fiow of fluid in the manner described, the heat generated in the conductors 23, 24 and 25 is conducted away therefrom by fluid acting both interioriy and exteriorly thereof.

Under some conditions a large measure of the heat absorbed by the reversely flowing fluid may be dissipated through the sheath 22 and other surfaces of the system without requiring a special heat-exchanger i2. In instances where the system extends up a hill, for instance, it is possible to dispense with the pump 10 under some conditions and rely upon the well-known thermosyphon action to effect the circulation of the cooling and insulating fluid,

The invention may be carried out in other specific ways than those herein set forth without departing from the spirit and essential characteristics of the invention, and the present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.

I claim:

1. An electric-power transmission-system including in combination: a first duid-chamber; a second fluid-chamber spaced from the said first huid-chamber; a hollow tubular sheath interconnecting said fluid-chambers in fluid-conducting relation; a plurality of hollow tubular electricalconductors extending longitudinally through the said sheath and into said duid-chambers and each providing a now-channel interiorly of itself,

" the said plurality of hollow tubular conductors occupying substantially less than the cross-sectional area of the interior of the said sheath to provide a fiow-channel exteriorly of the said plurality of conductors and interiorly of the said sheath; a plurality of electrical tap-offs extending through the walls of said fluid-chambers and connected to said conductors; and means interconnecting said interior and exterior iioW-channels constructed and arranged t0 cause insulating cooling-fluid to iiow along said flow-channels and fluid-chambers and over and in contact with the portions of said tap-oii's located in said fiuidchambers.

2. An electric-power transmission-system including in combination: a first huid-chamber; a second huid-chamber spaced from the said first fluid-chamber in duid-conducting relation; a hollow tubular sheath interconnecting said iiuidchambers; a plurality of hollow tubular electrical-conductors extending longitudinally through the said sheath and into said uid-chambers and each providing a flow-channel interiorly of itself, the said plurality of hollow tubular conductors occupying substantially less than the cross-sectional area of the interior of the said sheath to provide a flow-channel exteriorly of the said plurality 0f conductors and interiorly of the said sheath; a plurality of electrical tap-offs extending through the walls of said duid-chambers and connected to said conductors; and means including a heat-exchanger exterior of said sheath intei-connecting said interior and exterior flowchannels constructed and arranged to cause insulating cooling-fluid to flow along said flowchannels and huid-chambers and over and in contact with the portions of said tap-offs located in said fluid-chambers,

HAROLD C. DANIELS.

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