US2038367A - Process for the manufacture of concrete having a high electric insulation resistance - Google Patents

Description

Patented Apr. 21, 1936 UNITED STATES PROCESS FOR THE MANUFACTURE OF CONCRETE HAVING A HIGHELECTRIC INSULATION RESISTANCE Emile Pierre Claudius Lambert, Paris, France No Drawing. Application January 25, 1932, Serial No. 588,840. In France January 29, 1931 4 Claims.

This invention has for object a process for the manufacture of concrete having a high electric insulation resistance. It consists in mixing cement, impalpable silica, silicious gravel or broken silicious stone, extra-silicious sand, and diluting these materials with water, which contains bituminous materials or flower of sulphur. After complete setting of the concrete obtained the same is heat treated and covered with one or more layers of products of the above named category, or of products such as resinate of soda, bakelite and other insulating materials.

It is obvious that certain materials above indicated might be replaced by materials capable of fulfilling the same function.

The concrete manufactured according to the process forming the subject-matter of the present invention, has remarkable dielectric properties and constitutes a high grade waterproof insulating material. It has moreover the advantage of being of a cost price much lower than that of the insulating materials hitherto employed.

It is particularly suitable for the manufacture of insulators, for telegraphic and telephonic lines and for electric power supply lines, as well as for the manufacture of insulating members supporting the rails or current supply wires of electrified railroad plants.

The invention also relates to the articles such as posts, for supporting arms, insulators, railway sleepers, partitions, switchboards in electric power generating or receiving stations, insulating vats and the like, made of the special concrete above indicated, with or without incorporation of bituminous or like materials. This concrete, without being subjected to a treatment by heat, is rendered dielectric by application of one or more layers of products of the same category as those used for the manufacture of the concrete itself, or of products the main ingredient of which is resinate of soda, bakelite or other insulating substances.

The parts or members made of the said special concrete can be obtained by the ordinary methods or'also by trepidation, vibration or compression in suitable moulds or casings.

The following proportions, given by way of example only, can be employed for the manufacture of a concrete of the present invention having a high electric insulation resistance:

Cement 300 to 400 kgs.

Water (in variable quantity according to the season) The bituminous materials, about 250 kgs. for one cubic meter of finished product, which can be added when diluting are the following: tar or pitch obtained from stearine, asphalt, petroleum oil, etc. in the form of an emulsion.

The treatment by heat is efiected in a furnace or in a digester at a temperature of about 140 to 150 C. When use is made of a digester, the layers of the superficial coating can be replaced by an impregnation under pressure.

The applicant has found that the cements which give the best results are aluminous cements, so-called melted-cements and more particularly those manufactured by the Socit des Ciments de Lafarge et du Teil, at the Vitry-le- Francois and du Teil Works, so-called Waterjacket manufacture.

It is obvious that the process above set forth can give rise to numerous modifications which obviously are all included in the scope of the present invention.

What I claim as my invention and desire to secure by Letters Patent is:

1. Process for the manufacture of products made of materials having a high mechanical resistance and high electric insulating qualities, which consists in first mixing, in the cold state, fused aluminous cement, silicious gravel, supersilicious sand, impalpable silica, water in sufiicient quantity for the setting of the cement, and bituminous materials in a finely divided condition, then shaping the product in cold state, and final-- 1y subjecting the product to a heat treatment at about 140 C. after setting of the cement.

2. Process for the manufacture of products made of materials having a high mechanical resistance and high electric insulating qualities, which consists in first mixing, in the cold state, fused aluminous cement, silicious gravel, supersilicious sand, impalpable silica, water in sufilcient quantity for the setting of the cement, and flowers of sulphur in a finely divided condition, then shaping the product in cold state and finally subjecting the product to a heat treatment at about 140 C. after setting of the cement.

3. Process for the manufacture of products made of materials having a high mechanical resistance and high electric insulating qualities, which consists in first mixing, in the cold state, fused aluminous cement, silicious gravel, supersilicious sand, impalpable silica, water in sufiicient quantity for the setting of the cement, and bituminous materials in a finely divided condition, then shaping the product in cold state, subjecting the product to a heat treatment at about 140 C. after setting of the cement, and finally coating in cold state the product after its heat treatment, with a bituminous material similar to that incorporated in the mass.

4. Process for the manufacture of products made of materials having a high mechanical resistance and high electric insulating qualities, which consists in first mixing in cold state, fused aluminous cement, silicious gravel, super-silicious sand, impalpable silica, water in sufficient quantity for the setting of the cement, and bituminous materials in a finely divided condition, then shaping the product in cold state and subjecting the product to a heat treatment at about 140 C. after setting of the cement, and finally coating, in cold state, the product after its heat treatment, with resinate of soda.

EMILE PIERRE CLAUDIUS LAMBERT.