GB2138995A - Insulated electrical distribution line - Google Patents

Abstract

A distribution line for installation vertically in a building consists of parallel insulated conductors 12 enclosed in rigid ducts 14, the ducts being spaced apart at intervals so as to leave flexible portions 18 which allow the line to be folded for transport and to allow thermal expansion and contraction. The ducts 14 is in halves and has removable portions 20 to allow connection of electrical wiring. Protective plates may be attached between the ducts 14 to protect the flexible portions when the line is installed, or wires may be attached between the ends of the ducts to prevent stress on the conductors during installation; one of such wires may serve as an electrical earth (Figs. 21 to 26). Waterproof caps may be fitted to the ends of the ducts. Spring catches (48, Figs. 30 & 31) secure the duct as it passes through holes within the building. <IMAGE>

Description

SPECIFICATION Insulated electrical distribution line This invention relates to an elongate insulated electrical distribution line for buildings, factories and the like.

A conventional distribution line which is laid as a trunk line in a building or the like comprises a plurality of units, each having a length corresponding to the height of each floor of the building, 3 m, for example. The units extend through the respective floors of the building and are supported by spring hangers. The adjacent units are connected by joints to each other. Expansible portions may be provided at predetermined distances to absorb thermal expansion and contraction of the units. Also, fire-proof seals may be provided in floor holes th rough which the units extend.

However, in such known distribution lines the units are required to be jointed at the site and in addition thereto, the expansible portions are required to be separately provided because the units have no capacity for absorption of thermal expansion and contraction. Therefore, the efficiency of operation is relatively low and the duct disadvantageously has a lower reliability at the joints because of site operation. Furthermore, since the line tends to slidably move at the portion having the fire-proof seal, its construction is complicated, with the result that its cost tends to be high.

Distribution lines of this type are referred to hereinafter as "bus ducts".

It is a principal object of the invention to provide an elongate bus duct which requires no unit-jointing at the site.

It is another object of the invention to provide an elongate bus duct adapted to absorb thermal expansion and contraction without connecting any expansible portions thereto.

It is further object of the invention to provide an elongate bus duct adapted to be conveniently folded for carriage.

It is further object of the invention to provide an elongate bus duct which is made waterproof so that water never enters at the ends and branch points thereof.

It is further object of the invention to provide an elongate bus duct which can be easily laid without colliding against floors of a building when it is provided while extending through the floors of the building.

It is further object of the invention to provide an elongate bus duct which can be easily fixed to floors of a building and as a result easily laid.

In accordance with the invention, there is provided an elongate bus duct comprising a body of the bus duct including a plurality of elongate insulated conductors disposed in parallel to each other and having rigid portions and flexible portions alternately provided in a longitudinal direction.

The above and other objects and features of the invention will be apparent from the description of the embodiments shown in the accompanying drawings in which; Figure lisa front view of an elongate bus duct constructed in accordance with one embodiment of the invention and folded; Figure 2 is a cross sectional view of the elongate bus duct taken along the line 2-2 of Figure 1; Figure 3 is a cross sectional view of the elongate bus duct taken along the line 3-3 of Figure 1; Figure 4 is a front view of the elongate bus duct of Figure 1 laid in one form with floors broken; Figure 5 is a front view of one example of protecting means for a flexible portion of the elongate bus duct of Figurel; Figure 6 is a cross sectional view of another example of a flexible portion of the elongate bus duct of Figure 1;; Figure 7 is a front view of the elongate bus duct of Figure 1 laid in another form; Figures 8A and 8B are enlarged front and side elevational views of an elongate bus duct constructed in accordance with another embodiment of the invention, respectively; Figures 9A and 9B are cross sectional views of the elongate bus duct taken along the lines 9A-9A and 9B-9B of Figure 8A, respectively; Figure 10 is an enlarged perspective view of an insulated conductor for the elongate bus duct of Figures 1 and 8 with a portion broken away; Figures 11A, 118 and 11Carecrosssectional views of insulated conductors for the elongate bus duct in accordance with different embodiments of the invention, respectively;; Figures 12A and 12B are cross sectional views of a rigid portion and a flexible portion of the elongate bus duct having insulated conductors in another form, respectively; Figures 13A through 13D are cross sectional views of rigid portions similar to those of Figures 12A and 1 2B, but having the number of conductors different from each other, respectively; Figures 14 is a sectional view of an elongate bus duct having an upper end made water-proof; Figures 15 and 15A are perspective views of a branch portion of an elongate bus duct made waterproof and an end of a branch conductor therefor, respectively; Figures 16and 16A are perspective views of a lower end of an elongate bus duct made water-proof and a lower conductor portion therefor respectively;; Figure 17 is a perspective view of a portion of an elongate bus duct having an upper end of a rigid portion modified; Figures 18 is a sectional view of the elongate bus duct of Figure 17 extending through a floor of a building; Figure 19 is a front view of an elongate bus duct having tension members provided between adjacent rigid portions thereof; Figures 20A and 20B are cross sectional views of the elongate bus duct of Figure 19 taken along the lines 20A-20A and 20B-20B of Figure 19, respectively; Figure 21 is an enlarged perspective view of the tension member of Figures 19 and 20 connected between the adjacent rigid portions; Figures 22 is a perspective view of a portion of an elongate bus duct having tension members different from those of Figures 19;; Figure 23 is a cross sectional view of the elongate bus duct of Figure 22 taken along the line 23-23 of Figure 22; Figure 24 is a perspective view of a sheet of a metal plate constituting the tension members used for the elongate bus duct of Figure 22; Figure 25 is a cross sectional view of an elongate bus duct having tension members, one of which serves as ground conductor; Figure 26 is a cross sectional view of an elongate bus duct having tension members, one of which serves as ground conductor, but secured by means different from that of Figure 25; Figure 27 is a sectional view of a branch portion of the elongate bus duct of Figure 26; Figure 28 is a sectional view of an end of the elongate bus duct of Figures 25 and 26; Figure 29 is an exploded perspective viee of an elongate bus duct having flexible portions modified;; Figure 30 is a perspective view of an example of supporting means for the elongate bus duct; Figures 31A and 31B are front views of the supporting means of Figure 32 by which the elongate bus duct is sequentially supported; Figure 32 is a perspective view of another example of supporting means for the elongate bus duct; and Figures 33A through 33D illustrate how the elongate bus duct is sequentially supported by the supporting means of Figure 32 Embodiments of the invention will be described with reference to the accompanying drawings Figures 1 to 3 show an embodiment of an elongate bus duct of the invention The elongate bus duct comprises a plurality of elongate insulated conductors 12 disposed in parallel in a laminated manner, each of which comprises a flexible strip-like flat conductor 12A and an insulation 12B covering the flat conductor 12A.In the illustrated embodiment, the elongate bus duct comprises three elongate insulated conductors 12 for three phases. The flat conductors 12A may comprise a serial conductor or a plurality of conductor lengths sequentially connected by welding or the like. The elongate bus duct 10 has rigid cases 14 provided on an assembly 13 of the insulated conductors 12 in a spaced manner in a longitudinal direction. Rigid portions 16 are formed where the rigid cases 14 are provided while flexible portions 18 are formed where the rigid cases 14 are not provided. Thus, it will be noted that the elongate bus duct 10 has rigid portions 16 and flexible portions 18 alternately provided in a longitudinal direction. The length of the elongate bus duct 10 may preferably be approximately 50m, for example, which is necessary for a main line in a conventional building.

As shown in Figure 2, the rigid cases 14 comprises two case halves 14A and 14B flanged to each other so that they are tightened against the insulated conductor assembly 13. The rigid cases 14 may have a plug-in or tap conductor type branch portion 20 provided thereon. Connection boxes 22 may be provided at both ends of the elongate bus duct 10.

As shown in Figure 1, it will be noted that the elongate bus duct 10 can be carried in a compact volume by folding the flexible portions 18 in a S-shaped manner. As shown in Figure 4, the elongate bus duct 10 may be laid by pulling it up with a rope (not shown) of a hoist suspended from an uppermost floor 2 of a building 1 so that respective rigid portions 16 extend through holes 3 in respec tivefloors. Fire-proof seals 4 may be provided in the holes 3 so that the rigid cases 14 are air-tightly secured to the respective floors 2. The elongate bus duct 10 may be preferably laid so that the flexible portions 18 are slightly bent to have a bent portion.

As a result since the flexible portions serve as expansible portions for thermal expansion and contraction, expansible portions conventionally required are omitted.

The flexible portions 18 may be preferably protected either with a protecting cover as shown in Figure 5 or with flexible protecting plates 26 provided on both sides ofthe laminated insulated conductors tightened at both ends thereof with tightners 28 such as bolt and nut. The protecting cover 24 of Figure 5 may be preferably secured at one of its ends to the rigid case 14 so that the protecting cover 24 can slidably move along the rigid case 14 in thermal expansion and contraction.

As shown in Figure 7, the elongate bus duct 10 of the invention can be easily laid according to various laying routes within factories or the like if the lengths of the rigid portions 16 and the flexible portions 18 are so set that the flexible portions 18 are positioned at bent portions of the laying routes.

Figures 8 to 10 illustrate another embodiment of an elongate bus duct 10 of the invention, in which the insulated conductors 12 are particularly modified. In this embodiment, each of the respective insulated conductors 12 comprises a laminated conductor 12Aformed by laminating a plurality of metal strips (6 metal strips, for example) 12 such as copper strips having the thickness of 0.5 mm as particularly shown in Figure 10 with a sliding agent preferably disposed between the adjacent metal strips 12a and on the outer surfaces thereof. Oil, compounds or lubricating plastic sheets may be used as sliding agent. This causes the flexibility of the flexible portions 18 to further increase to enhance the thermal expansion and contraction of the elongate bus duct.In this embodiment, protecting plates 30 such as thin iron plates may be disposed on both laminating sides of the laminated insulated conductors 12 at the flexible portions 18 and secured at both ends to the rigid cases 14 by screws. It will be noted that the size of the insulated conductors can be easily selected by changing the number of lamination. In this embodiment, the rigid cases 14 are different from those of the aforementioned embodiment in that the former have reinforcing poritons 14b provided through webs 14a thereon.

Figures 11 to 13 illustrate other examples of the insulated conductor used for the elongate bus duct 10. In Figures 11Athrough 11C,each ofthe insulated conductors 12 comprises an elongate conductor 12A having a plurality of bare or insulated conductor elements 12b or 12c of rectangular or circular cross section disposed side by side in a line in a widthwise direction and an insulation 128 covring the conductor elements 1 2b or 1 2c collectively. It should be noted that a current of the same phase flows through the collected conductor elements 12b or 12c. This causes the flexibility of the flexible portions 18 to increase and also the insulated conductor 12 to be permitted to be bent in a widthwise direction.Thus, it will be noted that when the elongate bus duct 10 is laid by unfolding it from the folded condition, it can be advantageously proof against twisting. Figures 12Aand l2Bshowinsulatedcablesforthreephases of R, S and Teach having insulated conductors 12 disposed side by side in a line in a widthwise direction. Each of the insulated cables comprises a stranded conductor 12d and a sheath 12e provided through an insulated cover on the stranded conductor 12d as in a conventional manner. Figures 13Ato 13D show insulated cables having two, three, four and twelve insulated conductors 12 for each phase.

In these examples, since the insulated conductor 12 comprises a plurality of insulated cables, the elongate bus duct 10 can be easily manufactured at a low cost. It will be also noted that the insulated conductor 12 can be advantageously bent in a widthwise direction in the same manner as in the embodiment of Figure 11.

Figuresl4to l6showanelongatebusductl0 having both ends and branches made water-proof.

As shown in Figure 14, a water-proof cap 32 is provided on the upper end of the elongate bus duct 10 and, as shown in Figure 16, an end box 34 is provided on the lower end of the elongate bus duct 10. The ends 12C of the elongate insulated conductors 12 are exposed within the end box 34 and each provided with a connection hole 12f. Each of branches 20 comprises tap conductors 21 exposed from a connection box, connected to strip-like metal conductors 12A of the insulated conductors 12 and provided with connection holes 21a, respectively.

Insulated coverings 12E and 21b are provided on the conductor ends 12C within the end box 34 and the tap conductors 21 of the branch 20, respectively so that the elongate bus duct 10 is electrically insulated and also made water-proof. In Figure 14, reference numeral 36 designates a suspending member. In this manner, since the elongate bus duct 10 is made water-proof at both ends and at the branches, a laying operation can be advantageously made even during a rainy reason and therefore without any restriction of operation period. After the elongate bus duct 10 is provisionally laid, the insulated coverings 12E and 21b are removed by cutting them at lines 12G and 21C, the conductor ends 12C and the tap conductors 21 are exposed as shown in Figures 15A and 16A.

Figure 17 shows an elongate bus duct 10 has protrusions such as the rigid cases 14 modified. In this elongate bus duct 10, the rigid cases 14 and the branches 20 have tapered upper ends 14a and 20a, respectively. As shown in Figure 18, this permits the protrusions such as the rigid cases 14 and the branches 20 to smoothly pass through the extending holes 3 even though the upper ends of the rigid cases 14 and the branches 20 hit against the edges of the holes 3 when the elongate bus duct 10 is pulled up through the holes 3 in the floors 2 of the building 1. Thus, the elongate bus duct 10 can be prevented from being damaged.

Figures 19 and 20 show further embodiment of the invention. In this embodiment, the elongate bus duct 10 has tension members 38 and 38' such as wire ropes, fiber-reinforced plastic wires and the like provided between the adjacent rigid portions 16.

These tension members 38 and 38' are secured by fasteners 40 and 40' to the adjacent rigid cases 14 on the inner sides thereof. Figure 21 shows another example of the fasteners 40 and 40' securing the tension members 38 and 38' to the corresponding rigid cases 14. In this example, the fasteners 40 and 40' are in the form of a two-part clamp which secure the tension members 38 and 38' to the corresponding rigid cases 14. The elongate bus duct of this embodiment can be vertically laid without applying a tension to the insulated conductors 12 and especially to the flexible portions 18.

Figure 22 shows another embodiment of the invention in which the tension members are modified. In this embodiment, the tension members 38 and 38' comprises a sheet of thin plate 39 such as stainless steel plate, fiber-reinforced plastic plate or an iron plate or a laminate of such thin plates 39. The thin plate 39 or the laminate thereof is secured to the rigid case 14 by bolts 40 extending through holes 39a in the thin plate or plates 39 and screwed into the rigid case 14. Since the tension members 38 and 38' comprise a laminate of thin plates, the number of laminating sheets can decrease at the lower portions of the elongate bus duct 10 to which a lower load is applied and corresponding to the size and volume of the elongate bus duct 10, which causes the cost to be saved.Also, since the tension members 38 and 38' have a flexibility, the flexibility of the flexible portions is never prevented.

Figures 25 through 28 show another embodiment of the invention in which one of the tension members 38 and 38' serves as a ground conductor. The tension members 38 and 38' comprise an elongate aluminium stranded wire having a steel core. They may be secured to the rigid cases 14 either by disposing them in inner recesses 14c in the rigid cases 14 and tightening the rigid cases 14 so as to tighten the tension members 38 and 38' to the rigid portions 16 as shown in Figure 25 or by tightening the tension members 38 and 38' to the rigid cases 14 by tighteners 42. The steel core of the aluminium stranded wire for the tension members bears a tensio while the aluminium strand serves as ground conductor. As shown in Figure 27, branch conductors 21 connected to the exposed conductors 1 2A of the insulated conductors 12 are exposed from a branch box 20A while a branch ground taps 39 connected to one of the tension member 38', for example is exposed from a branch box 20A. As shown in Figure 28, the end of the tension member 38' is connected to a terminal base 44 within the end box 34. Since the tension member serves as ground conductor, a separate conductor (earth) is not required to be provided, which causes the cost of material to be saved.

Figure 29 shows another embodiment of the invention in which the flexible portions 18 are modified. In this embodiment, the bent portions of the insulated conductors 12 at the flexible portions 18 are so set that all of the bent portions are not in the same direction, but both sides of the laminate are reversely faced while the middle insulated conductor 12 is directed in either of the directions. It will be understood that this can further increase the flexibility of the flexible portions 18. In Figure 29, a reference numeral 46 designates a reinforcing plate screwed to the rigid case 14 on both sides thereof.

Figure 30 shows another embodiment of the invention in which the elongate bus duct 10 can be easily passed through and secured to the floors 2. As shown in Figure 30, there is provided self-movable fastening means 48 on both sides of the rigid cases 14 of the rigid portions 16. The fastening means 48 comprises a pair of equilateral right-angled triangu larfastening members 52 and 52' pivotally supported on the rigid case 14 and normally urged by a spring 54 to be pulled toward each other so as to be opened with bottom sides in a horizontal manner.

Stop pins 56 and 56' maintain them at this condition.

As shown in Figure 31A, since the oblique sides of the fastening members 52 and 52' of the fastening means 48 are forced against the spring 54 by the edge of the hole 3 when the elongate bus duct 10 is pulled up through the floor 2 from the underside thereof, the fastening members 52 and 52' rotate about the centers of the pins 50 and 50' so that the oblique sides of the fastening members 52 and 52' are retracted on the inner side of the rigid case 14to permit the fastening means 48 to pass through the hole 3 in the floor 2. As shown in Figure 31 B, after the fastening means 48 fully pass through the hole 3, the fastening members 52 and 52' return to the original position by the function of the springs 54 so that the bottom sides of the fastening members 52 and 52' engage the upper face of the floor 2, which prevents the elongate bus duct 10 from falling out of the floor 2.Thereafter, the elongate bus duct 10 can be secured to the floor 2 by screwing bolts 58 and 58' into screw holes 52a and 52'a.

Figure 32 shows another embodiment ofthe invention in which the fastening means 48 is modified. In this embodiment, the fastening means 48 comprises fastening members 52 and 52' of angle material which are secured by screws 60 to the rigid cases 14 afterthe elongate bus duct 10 has passed through the holes 3 in all the floors 2. Figure 33 shows the sequence in which the elongate bus duct 10 is secured by this fastening means 48. As shown in Figure 33A, after the elongate bus duct 10 pass through all the floors 2, the vertical portions of the fastening members 52 and 52' ofthe fastening means 48 are secured by screws 60 to the rigid cases 14. Thereafter, the elongate bus duct 10 is gradually lowered.In this case, as shown in Figure 33B, the fastening members 52 and 52' on the lowest rigid case 14 engage the corresponding floor 2 and as the elongate bus duct 10 is further lowered, the fastening members 52 and 52' on the rigid cases 14 on the upper side thereof sequentially engage the corresponding floor 2 as shown in Figures 33C and 33D.

After that, the horizontal portions of the fastening members 52 and 52' are secured by screws 62 to the corresponding floor 2. In this manner, the elongate bus duct 10 is secured so that bent portions are formed at the flexible portions 18.

While some preferred embodiments of the invention have been illustrated and described with reference to the accompanying drawings, it will be understood by those skilled in the art that they are by way of examples, and that various changes and modifications may be made without departing from the scope of the invention.

Claims (22)

1. An elongate bus duct the body of which includes a plurality of elongate insulated conductors disposed in parallel to each other and having rigid portions and flexible portions alternately provided along their longitudinal direction.

2. An elongate bus duct as set forth in claim 1, wherein said rigid portions comprise a rigid case provided on said body of bus duct.

3. An elongate bus duct as set forth in claim 2, wherein said rigid portions have a branch provided on said rigid case.

4. An elongate bus duct as set forth in claim 1, wherein said elongate insulated conductors comprise a strip-like metal plate and an insulation covering said metal plate.

5. An elongate bus duct as set forth in claim 1, wherein said elongate insulated conductors comprise a laminate of metal strips and an insulation covering said laminate.

6. An elongate bus duct as set forth in claim 1, wherein said elongate insulated conductors comprise a plurality of conductor elements disposed side by side in a line in a widthwise direction and an insulation covering said conductor elements collectively.

7. An elongate bus duct as set forth in claim 1 wherein said elongate insulated conductors comprise a plurality of insulated cables disposed side by side in a line in a widthwise direction.

8. An elongate bus duct as set forth in claim 1, wherein said insulated conductors are made waterproof at both ends thereof.

9. An elongate bus duct as set forth in claim 3, wherein said branch is made water-proof.

10. An elongate bus duct as set forth in claim 1, wherein said rigid portions are tapered at the upper end thereof.

11. An elongate bus duct as set forth in claim 3, wherein said branch is tapered atthe upper end thereof.

12. An elongate bus duct as set forth in claim 1, and further comprising tension members so provided between adjacent rigid portions as to stride across each of said flexible portions.

13. An elongate bus duct as set forth in claim 12, wherein said tension members comprises a thin plate or a laminate thereof.

14. An elongate bus duct as set forth in claim 1, wherein at least one of said tension members serves as ground conductor.

15. An elongate bus duct as set forth in claim 14, wherein said tension members comprise a stranded aluminium wire having a steel core.

16. An elongate bus duct as set forth in claim 1, wherein said flexible portions have a bent portion of said insulated conductors.

17. An elongate bus duct as set forth in claim 1, wherein said flexible portions have protecting plates covering said insulated conductors for protection thereof, and secured to said rigid portions on both sides thereof.

18. An elongate bus duct as set forth in claim 2, wherein said rigid case has fastening means to secure said rigid case to a supporting body.

19. An elongate bus duct as set forth in claim 18, wherein said fastening means comprises a pair of fastening members pivotally supported on said rigid case and normally urged to stretch in the horizontal manner so as to engage said supporting body, but turning-to allow the passage of said rigid case through the hole in said supporting member when said fastening means passes therethrough.

20. An elongate bus duct as set forth in claim 18, wherein said fastening means comprises at least one fastening member to be secured to said rigid case and also to said supporting body by screws.

21. An elongate duct for containing insulated conductors, substantially as herein before described with reference to, or as shown in, any of the accompanying drawings.

22. An elongate duct as claimed in any preceding Claim, when installed in a building.