DE7531935U - Tube-like hollow body, preferably with a circular cross-section for wrapping a base - Google Patents

Description

DR.-ING. GERALD KLDPSCH 5000 COLOGNE 1

PATENT ADVERTISER MARSPLATZ 11

October 7, 1975 Kl / Sn

Raychem Limited,

Moor House, London Wall, London EC2Y 5HP (England '»

Object_for_ wrapping_of documents, in particular- ^ §r5_5yr_5? R§ ^ Iiyi} g_Y2i} _ ^iio 2!} §P ^a Oi} yi} S5 ^{: i} - ^s 2i ?: ^t 2r ^en 52 ^ i§_y?} ^ §E_Y§ r ^ 5i} ^ y ⁿ S_4i ^e §- ^s composite structures made of the object

The invention relates to an object for wrapping documents, in particular for the manufacture of an insulator for high voltage purposes. The invention also relates to verbal structures on the basis of this subject.

In the area of high voltages, insulators (or insulating units) e.g. used to support overhead lines that are either under pressure or tension or in the fall e.g. mast insulators in substations and device bushings for transformers and switching devices Ensure a leakage path between the parts with high potential and the earthed parts. The outer surface of a such an isolator generally has a number of compartments for increasing the creepage distance and the over-voltage and to reduce stray currents. The compartments also form a number of protected ones Areas, which contributes to the improvement of the overall behavior of the isolator. A compartment or roof is considered to be the specialist a portion known which extends from the surface of the insulator outwardly and around the circumference, whereby

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create a ridge, hem, or ridge around the insulator's perimeter run around.

In the past, the above were generally used Insulators made from an insulating material such as porcelain or, in the case of suspension insulators, glass. The smaller ones Units, e.g. 33 KV, column insulators and 11 and 35 KV Device entries or bushings for transformers and switching devices are manufactured as individual units, with the Device bushings are hollow to accommodate the metal components at a high potential. With increasing size it will making one-piece insulators more difficult. One therefore usually provides a number of separate units which, in the case of device bushings and column insulators, are glued together to form a complete structural unit cemented or cemented and, in the case of suspension insulators, generally connected by metal connectors, which are glued to the glass or the ceramic mass. Although such isolators have advantages in that they require relatively cheap starting materials, they have the disadvantage of expensive production and are heavy and relatively fragile.

Recently, proposals for the manufacture of insulators from plastic materials have also been made. the the most widely used materials are epoxy resins and the insulators or their components are cast or molded has been manufactured. So in GB-PS 1,345,566 a Method described in which a central rod and the desired number of compartments are molded from plastic as a whole j will be. Such a production in one piece, however, has the part that for each component a different one 'Form must be used. It would therefore be advantageous if the roofs were made separately from the central rod so that they could be attached to any isolator. If the roofs are separated from the

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gate body would be produced, if desired, d \ e could be used as the insulator made of a material different from the insulator body v / ground outer surface. Thus, for example, a material could be used for the insulator body which, although otherwise suitable as an insulator (e.g. its cheapness and / or its light weight), has relatively poor electrical properties if this material is made of one with an outer surface and roofs is provided with leakage current-resistant insulating material.

It has already been proposed to make an insulator by gluing a number of individual roofs to a fiberglass core. In GD-PS 1,292,276, for example, the installation of a number of individual heat-shrinkable compartments on a central carrier is described. Even if heat-shrink ^; 15 capable roofs are used, however, is the manufacture

ι and installing a number of different roofs are inevitably time consuming and can lead to undesirable variations in the quality of the end product. It would therefore be beneficial! when the roofs would form part of an outer covering applied to the central beam as a single unit. Attempts to manufacture an insulator with an outer covering by molding a tubular part with a number of roofs, converting this tubular part into a heat-shrinkable shape and then shrinking it around the insulator, however, have not been successful because there is air between the tubular part and the insulator is enclosed and the roofs are bent or ^{: are} distorted so that they are no longer perpendicular to the surface of the fuse. Such warpage or warpage occurs randomly, with some roofs forming an acute angle and others an obtuse angle with the longitudinal axis of the part with the result that not only is the final product unsatisfactory, but in some cases the outer ends of the roofs so close stand together that it

J35 comes to a rollover between two neighboring roofs. White

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ter, upward-facing roofs tend to collect vvas-.

water, if the isolators are used outdoors, with the ^; Result that the electrical properties are impaired '! will.

The invention therefore relates to an outer covering for j a pad that can be attached quickly and easily | can and after the installation a desired configura-I tioii. j

The invention also relates to a resilient gel object, which before the deformation in the resilient

State has a particularly desired configuration and after resetting the document to this confi ι

guration returns or maintains it. ^!

'The invention is further provided with a roof-shaped projections electrically insulating sheath, which can be mounted on an electrical insulator 1, in order to provide these with an electrically insulating j Obrrfläche a desired shape. !

The invention also relates to the creation of a resilient insulating sheath which has a plurality of substantially vertical roof-shaped projections and those related to an electrical component such as a transformer. gate bushing, a pillar insulator or a fuse j can be restored without any appreciable deformation of the roofs j can.

It is a further object of the invention to provide a composite structure, such as an electrical insulator, of which Surface has a particular desired configuration, i

The invention provides a resilient hollow article

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for wrapping a pad having at least one open end and at least one outwardly extending portion, the outwardly projecting portion extending around at least a portion of the perimeter of the article. The inner dimensions of the object !, obtained with free restoration without a pad, are ι slightly smaller than the outer dimensions of the pad! is essentially the same as that obtained with free restitution (without a pad).

The invention further provides a composite construction which has a base on the outer surface of which a hollow resilient article having at least one open end and at least one outwardly projecting part is applied, the outwardly projecting part extending around at least one Extends around part of the perimeter of the article and the article exhibits only a low degree of "undissolved" (ie, incomplete) recovery. The incomplete provision is such! that when the pad is removed and the object is full; is reset, practically no change in the angle • occurs between the outwardly projecting parts and the longitudinal axis of the object. The maximum degree of reserve: within the phrase "minor degree" varies from! Object to object, however, the limit values

easily determined by simple routine experiments.

The composite construction is made by placing the resilient hollow object around the base with at least one open end and at least one outwardly extending portion, the outwardly extending portion extending around at least part of the circumference of the ' object and the Internal dimensions of the object ^:

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des when completely restored without a pad are slightly smaller than the outer dimensions of the pad, so that
when restoring the object around the document of the
Angle between the outwardly projecting parts and the
The longitudinal axis is essentially the same as the angle,

which is obtained if the item is returned without a document and then the object around the pad! caused to reset. As mentioned, the subject the invention a hollow body and at least one to the outside

Ilο protruding part on, which is at least a part
around the circumference of the object. If the after
Outside protruding parts are roofs made of electrical insulating material, they advantageously run continuously around the entire circumference of the hollow body. Run after; externally protruding parts only around part of the circumference, i can put the object in a form suitable for wrapping ^; be brought, for example, after the molding, is attached long. The outwardly protruding parts ^: Ie and the rest of the object consist of!

one piece.

The article according to the invention is advantageously produced by compression molding. If there are several outwardly projecting parts, each of these parts after molding (and also in the fully recessed form) is preferably substantially perpendicular to the longitudinal axis of the hollow part. "Substantially perpendicular" includes all configurations, ■ wherein a longitudinal direction of disassembly in the form of!

i the object can be removed without any substantial damage

formation of the outwardly protruding parts occurs.

j5o The object according to the invention are de internal dimensions; of the resilient hollow part after resetting in the essence of the base is only slightly smaller than the external dimensions of the base. A small difference is necessary
since, if the dimensions were identical, the object had none

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Restoring force would exert on the base and therefore could be removed from the base relatively easily. However, if the difference is small, it is ensured that the article has minimal residual recovery after attachment (i.e. that it is almost the original Dimensions reached immediately after shaping), so that the outwardly protruding parts (hereinafter briefly Called "protrusions") may show a tendency to deform due to internal stresses in the object. If the subject is heat-divisible and consists of a material, whose thermal expansion is large compared to that of the base, the forces between the object are also increased and the pad after resetting at zero reset temperature. In other words, he has Object at this temperature, although not at room temperature, would have the same dimensions as the original object at the same temperature, so that im there are essentially no stresses resulting from the deformation in the heat-recoverable state and no tendency exists that the projections deform during installation.

Although the preferred difference between the outer dimensions of the base and the inner dimensions of the completely restored object depends on the circumstances, the internal dimensions of the completely restored object are preferably no more than 1J>% smaller, based on the inner dimensions.

j dimensions, as the linear outer dimensions of the base. j If the difference is too small, however, the refa.hr, J that a heat-resilient article made of a material with po a high coefficient of thermal expansion compared to the base does not touch the base at the reset temperature, so that air is trapped between the object and the base . For such heat-resilient objects, the difference in dimensions is advantageously not less than 2 %.

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The inner surface of the object of the invention is advantageous

so shaped j, ■ that the escape of air from the intermediate U space between the object and the base during the back; ment is facilitated. The inner surface therefore has a: or several longitudinal grooves or grooves'. Also, the cross section of the inner surface of the Ge-j object in the resilient state ■ om the cross-section of the I. Be different, · whereby channels are formed through which the air can escape during the recovery. For example, the object can have a polygonal inner surface (which can be achieved, for example, by using a dome with a polygonal outer surface can be generated during the expansion of the object), while the base has a generally cylindrical outer surface.

; 15 The hollow body according to the invention exists from the time of its manufacture to the final installation on the! Document in at least three different states. These are the essentially dimensionally stable state in which the object is formed, a first resilient state in which the internal dimensions are large enough that the object can be slipped over the base, and '. a second recoverable state, in which the object has been recovered around the base with the formation of a composite structure, but through the base at the complete recovery in its original di-

unstable state is prevented. In the second recoverable state, the object is partially recovered and has "incomplete" recovery, which according to the invention is kept at a minimum. The recovery of the object is advantageously effected by heating, but if necessary it can also be done by the action of a solvent or by removing a stiff insert _;

, j

are triggered, which the object in the resettable supply ' withstands.

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The degree of expansion of the object from the state, which is essentially stable with respect to the effects of the arms, into the first heat-resilient state, which leads to an increase. of the inside diameter can be small, zl up to about IJ %, j 5 or large. It is advantageous if the degree of expansion is small and

preferably even if he is tall, the or everyone will follow; outside protruding part, e.g. 3. that or each individual screen ^; prevented or each individual roof from moving appreciably from \ the perpendicular remove during the expansion process to. Ic This can easily be done by mechanical means, e.g. by clamping the roofs or umbrellas, or in the event that! there is a multitude of outwardly extending parts by using comb-like devices with a! Number of suitable spatially separated teeth '15 or plates, which are georacht in contact with the outwardly projecting parts.

Although the invention is in no way limited to particular types of ■ objects and documents, it is particularly 'useful to electrical cables or electrical 3auteile, eg' ■ a fuse, a transformer bushing or a 'Support insulator with a one-piece order - [to be provided with a cladding that has a large number of roof-shaped projections. As mentioned, these roofs are preferably perpendicular to the longitudinal axis of the insulator to facilitate manufacture. Vertical roofs have the advantage that they give a clean appearance p; ee; en over sloping roofs, > for whom a large number of insulators are arranged at different angles to one another. If the object is used to enclose an insulator used in a vertical position, it can be used for any V / eg upwards. If pitched roofs are used, they must be sloped downwards to prevent the accumulation of rainwater.

The subject matter of the invention can contain any material which can be converted into the heat-resilient state.

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i th, which is in the heat-recoverable state through networking, ι if necessary, and expansion can be transferred v / ground, the j type of material is prescribed by the use of composite construction j. Therefore, if the composite structure is rated as high-5 Voltage isolator is used, at least the outer surface of the composite structure should normally have a creep

! contain current-resistant electrical insulating material. A sol-1

ches creepage resistant material can be defined by

an initial creep stress greater than J> KV according to ASTM-Io D2303-64T (wetting agent Triton X-IOO). In this test method, the contamination of inclined plates with liquids is determined. She is meant to be the operational! behavior of isolators under polluting conditions

to show. Examples of non-tracking materials that can be transferred into the warm resilient state • ^ 5, in British Patents 1,292,276, 1,284,081 and US applications

oil ^^ ö
273 991 > 274.110 and / mentioned. The object according to the

I can be found e.g. by compression molding, transfer molding or

^! Injection molding and after removal of excess

l2o liquid material in any way, either automatically

j or manually, can be expanded.

If desired, the heat recovery article is bonded to the carrier by means of an adhesive. Likewise at least a part of the surface of the object that is in contact with the support or the base with

be provided with a stress-reducing material or a layer, ie with a material or a layer that can reduce the dielectric stress that can be present in different areas of high-voltage components, eg | j5o at the end of a shielding of a high-voltage cable. Suitable adhesives are especially those, for example, epoxy resins (cured either hot or cold) and polyester ge-I Nannt, di-s may be used without fillers or \ and silicone-based adhesives, with

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properties without leakage current. Other suitable adhesives can include copolymers of hydrocarbons with at least one; ner polymerizable double bond with compounds containing at least one double bond to polytnerisierbare-5 samrnen with one or more Carboxylgrupoen or have their] derivatives, for example esters or anhydrides. Examples I of such copolymers are ethylene / vinyl acetate copolymers;

1 ethylene / ethyl acrylate copolymers, methyl vinyl ether / maleic acid { anhydride copolymers and preferably alkyl esters of methyl

Called io vinyl / maleic anhydride copolymers. As a tension Diminishing material or layer is a material with linear or preferably non-linear electrical resistance suitable, which has dimensional stability or an essentially non-crystalline material (e.g. a putty-15 Contains similar material1 that has a viscosity of not

is greater than 10 'cp at 25 ° C. Examples of those who Voltage grading materials are described in the US application 393- ^ 09 and the CB- / 13052/73 given. The aspects of Spanj Voltage reduction and tracking resistance can be combined in one

2 ο object or construction according to the GB patent application 43.613 / 74 combined.

i The invention is exemplified below with reference to the Figui ren described:

Figure 1 is a longitudinal section through a casing for a 25 Insulator in a heat-stable condition.

Figure 2 shows the envelope of Fi ^ ur 1 irr, expanded would-

: restorable condition.

i Figure 3 shows the wrapping of Fif-.ur 2, shrunk around

^! a backup.

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1 shows a longitudinal section through an object 10 which comprises an elongated central part 11 and a number of roof-shaped projections 12 which are essentially perpendicular to the central part 11 so that the ce ^ .en-

j stand can be easily shaped. In Figure 1, the rain!

was in a dimensionally stable form when exposed to heat. 'A heat-recoverable form 10' of the object 10 is! shown in figure 2. In this form of Ge can enstand _f j is an insulator around are arranged, the outer-j

: lo knife between the inner diameters of the forms 10 and 10 'ι is (z.3. A glass rod 13 with metallic end capo 14, as shown in Figure j5 ¹ ). The item can be heated. * And then shrinks tightly onto the rod, as in Figure 3

: shown. j

In all three figures the roofs 12 are essentially;

ι perpendicular to the central part 11. According to the invention

the inner diameter of the middle part 11 and the outer diameter

; knife of the rod 13 chosen so that this essentially

: vertical arrangement in the composite construction (see figure j? V

! 2o is obtained. However, it is not necessary that this lowering;

ί right-hand arrangement in the heat-restoring,

state is retained. Some deformation of the roofs i can occur in this state, provided that the ab- '

ι measurements are such that the vertical arrangement in the ί

j25 collar construction is obtained.

, Object and composite construction according to the invention are illustrated in the following examples:

3 examples 1-3

Three sleeves that have a multitude of roof-shaped protrusions. are formed from an electrically insulating material. In any case, the roofs face a similar one Have a shape as in Figure 1, substantially perpendicular

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to the longitudinal axis of the sleeve and are symmetrical to a plane j perpendicular to this longitudinal axis. Each sleeve is converted into the heat-resilient state by heating, expanding over a mandrel and cooling, whereupon the sleeve is removed from the mandrel. Each of the heat recoverable articles is then placed around a suitable cylindrical fuse and heated to shrink onto the fuse. In one! In a separate experiment, resettable objects, which are identical to those shrunk onto the fuses, are heated in the absence of a base in order to determine the diameter of the fully retracted stand. ^!

The inside diameter of the heat exchangeable objects; and the outside diameter of the fuses as well as the inside diameter the fully set back sleeves are given in the following table; The table shows at the same time the. Percentage of the remaining resetting of the sleeves after resetting and the fuses after the following Equation is calculated:

% still existing provision = outer diameter shown See-! tion - inner diameter of the fully recessed j

χ

Inner diameter of the fully recessed socket

number Ta be lie Inside $ still the Inside Outside knife de .. exist at roofs knife of the knife the fully back dene games heat return Fuse posed Back part capable (cm) Socket (cm) stel against lung 5 stands (cm) 5.77 8.81 8th 6.43 6.2 " 6.35 8.79 ' 2 11th 7.06 6.91 6.96 8.38 3 7.75 7.54

The roofs of those sleeves that open the fuses were shrunk on, essentially lowering right to the longitudinal axis of the sleeves. ■

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Claims (11)

*
I * Cologne, August 30, 197 <Kl / En EXPECTATIONS J, -) '^ Tube-like hollow body, preferably with a circular Cross-section for wrapping a base ^> characterized in that that the hollow body has at least one open end and a plurality of around at least part of the Has circumferentially extending projections in the dimensionally stable State of the hollow body are perpendicular to its longitudinal axis. 2) Hollow body according to claim 1, characterized in that the projections are also substantially perpendicular to the longitudinal axis of the dimensionally unstable hollow body. 3) hollow body according to claim 1 or 2, characterized in that each outwardly projecting part extends around the entire Extends circumference around. 4) hollow body according to one of claims 1 to 3, characterized in that that outwardly protruding parts and the rest ' Part of the hollow body consist of one piece. ; 5) hollow body according to one of claims 1 to 4, characterized by • draws that it consists of electrically insulating material. 6) Hollow body according to claim 5, characterized in that each outwardly projecting part as a roof-shaped projection is trained. 7531935 12/23/76 JJ t> S * # ft 7) Hollow body according to one of claims 1 to 5, characterized in that its inner surface has at least one in
Longitudinal deformation to escape from
Air from the space between the hollow body and the base «: has. 8) Hollow body according to one of claims 1 Iris 5, characterized in that the inner surface has one or more
Has grooves or grooves running in the longitudinal direction. _R that it comprises 9) A hollow body according to claims 1 to 8, characterized in an insulating layer on the inside of the hollow bodies containing pers and an elongated central part.! 10) Hollow body according to claim 9, characterized by a content of material resistant to tracking current. i 11) hollow body according to claim 9, characterized in that we-j at least a part of the inner surface of the central part, j with a layer of a material with linear or non-, linear electrical resistance behavior or other j suitable voltage-regulating properties is provided. 7531935 12/23/76