LU83226A1 - INSULATION OF ELECTRIC CURRENT TRACKS - Google Patents

Description

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3. Name and first names _______________ .. Ll ...._________________________________________________________________________-.................................... .................................................. ........................

Address __________________________________________________________________________________________________________________________________________________________________________________________________________________________________

He asserts the Sincerity of the above indications and declares to assume full responsibility for them. /

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: (signature) A 68026 ___ | ___ (') Last name, first names, company, address.

P) Name. Name and address of the denosanf

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Patent application of. * March 18, 198 1 Designation of the Inventor 0 The undersigned jean Waxweiler, 21-25 Allée S chef fer LUXEMBOURG acting as dexdsposoaic— agent of the depositor - 0 SIGMA ... CQAT.ING ... B _V ................................................ ; ....................................._............ ...............................

14, Amsterdamseweg

1220 UITHOORN, THE NETHERLANDS

(') of the invention relating to:

Insulation of electrically conductive rails, designated as inventor (s):

William David DAVIES _ _ ____

Shepharas "ay

Lower Station Road f® "1 * L ° a9e„.

Newtek East Sussec BN8 4HT Brandbury Road

Great Britain ° xfoJa „„ »Great Britain

Mr. R.J. BEAUMONT Spinacres

Cray Hills-Billericay,

Essex ''

Great Britain i

He affirms the sincerity of the above-mentioned indications and declares to assume full responsibility for them. This designation of the inventor replaces any designation of the previous inventor that it cancels.

Luxembourg ............................., "e -22 3uil 1-et ........... .......— 19 .... 8..2 ..

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(slgnaturei ^ I * ____________________ i, ^ * DESCRIPTIVE MEMORY filed in support of a

PATENT INVENTION APPLICATION

formed by the so-called Company: SIGMA COATINGS B.V.

for

INSULATION OF ELECTRIC CURRENT TRACKS

The present invention relates to a method of insulating conductive rails of electric current, used in the tracks of certain railways.

A railway electrification system consists in using, between the two usual rails, a third rail which serves as a connector. electric current driver supplying the wagon train traction machine. This system offers certain advantages compared to the catenary electrification system.

However, it has a drawback: during the maintenance or repair of the tracks, metal tools manipulated by workers can accidentally come into contact with the electric current conductor rail, whose voltage exceeds 700 volts and can even reach 900 volts , hence fatal accidents.

It can therefore be seen that it is necessary to have a solution which makes it possible to remedy this drawback. The object of the present invention is to provide this solution, by partial insulation of the electric current conducting rail.

The method of the present invention consists in applying to the lower part and to the sides of the electric current conducting rail an insulating composition essentially comprising a mineral filler, an insulator, and a binder consisting of an epoxy resin.

The composition applied to the parts of the rail mentioned above must meet certain criteria for it to act effectively. It must not only have an insulating action, but it must also have sufficient mechanical properties, in particular from the points of view of impact resistance, abrasion, oils, greases, as well as weathering.

The choice of filler depends not only on the desired insulating properties, but also on other factors, such as price and ease of supply. It is possible in particular to use a mineral, pulverulent filler, such as sand, silicate, clay, kaolin, chalk,> crushed slate, or a fibrous filler, such as fiberglass or the like, or a mixture of such fillers. The amount of filler can vary within wide limits, ranging from about 60% to about 85% by weight and even more, based on the total weight of the composition. More generally, - 3% of the filler material will be used in an amount varying between approximately 70 and 80% of the total weight of the composition. According to one embodiment of the invention, this filler material consists of quartz sand, the particle size of which is advantageously between approximately 0.1 and 0.3 mm.

epoxy

The binder consists mainly of a hardenable resin. By the terms "epoxy resins" is meant not only the resins obtained from epichlorohydrin and an organic hydroxide compound, but also copolymers, including for example epoxy-silicone resins, as well as mixtures consisting of a most of epoxy resin and less organic polymer compatible with epoxy resins. Use may, in particular, be made, as compatible organic polymer, of polyamides, novolaks and the like, which make it possible to improve certain particular characteristics of the coating applied to the rail. The amount of binder in the composition can be between approximately 15% and 40% of the total weight of the composition. The binder is used in a proportion which is at least 15%, based on the load weight. On the other hand, a proportion of binder exceeding 25% of the weight of the filler does not lead to a significant improvement in the qualities of the insulating coating.

The composition of the invention advantageously comprises a thixotropic agent. Thanks to the addition of such an agent, the composition is in the form of a stable, homogeneous product having a viscosity such that it can be applied easily, by any suitable means,

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including spraying. In addition, after application to the rail, the composition forms a coating which has no tendency to flow from the support. Among the thixotropic agents used in the composition of the invention, there may be mentioned colloidal silicas, in particular i - 4 t silica gels, as well as bentenites modified with amines, n alkali or alkaline earth salts of higher fatty acids, etc ....

The amount of thixotropic agent possibly added to the composition of the invention generally does not exceed 5% of the total weight of binder and mineral filler and it is most often between approximately 1% and 2% by weight.

The composition of the invention may also contain pigments and other additives, such as liquid diluents. Some of these diluents, such as glycidyl esters of versatic acids, are reactive. These various additives "when incorporated into * the composition of the invention, are used in an amount which generally does not exceed 5% of the total weight of the composition.

The composition of the invention is applied to the lower part and to the sides of the rail which has been previously cleaned, for example by sand blasting, and which may also have been treated beforehand, as a preventive measure, with a layer of protective product. . In view of its application, the composition is mixed beforehand with a usual hardening agent for epoxy resins. The necessary quantity of hardening agent varies according to the type of epoxy binder used and the nature (acid or basic) of this agent. In the case of the compositions of the invention, this amount can be between approximately 2 and 10% -. , based on the total composition weight.

As an example, a basic hardener can be used in an amount of about 4 to 6%, calculated on the total weight of the composition.

% - Example

In a mixer fitted with an agitator, a composition is prepared from: - epoxy resin (reaction product of epichlorohydrin and bisphenol-A) 15.5% by weight

Claims (10)

1. A method of partially insulating rails conducting electrical current, characterized in that an insulating composition comprising essentially an insulating mineral filler and a binder consisting of an epoxy resin is applied to the lower part and the sides of the rail. 2. Method according to claim 1, characterized in that the filler is a pulverulent filler, such as a sand, silicate, clay, kaolin, chalk, crushed slate, or a fibrous filler, such as glass fibers, or a mixture. 3. Method according to claims 1 and 2, characterized in that the amount of filler is approximately 60 to 85% and advantageously approximately 70 to 80%, of the total weight of the composition. 4. Method according to claim 1, characterized in that the epoxy resin V is an epoxy-silicone copolymer or a mixture of epoxy resin and a lesser amount of compatible organic polymer, in particular a potyamide, a novolak or the like. 5. Method according to claims 1 and 4, characterized in that the binder is used in an amount of 2 to 10%, in particular 4 to 6% t * '- 6 fr of the weight of mineral filler. Ί 6) Method according to claim 1, characterized in that the composition contains a thixotropic agent, in particular colloidal silica, in an amount not exceeding 5% of the total weight of filler and binder and advantageously between 1% and 2% of this total weight. 7. Method according to claim 1, characterized in that the composition also contains pigments and other additives in an amount not exceeding 5% of the total weight of the composition. 8. Method according to claim 7, characterized in that this additive is a glycidyl ester of versatic acid. T, 9) Method according to claims 1, characterized in that, at the time of the application of the insulating composition, the latter is mixed with a hardening agent for epoxy resin. _ 10) Partially insulated rails as obtained according to the method of claims 1 to 9. V *