US1802071A - Composition - Google Patents

Description

Patented Apr. 21, 1931 UNITED STATES PATENT OFFICE WILLIAM HOWARD WRIGHT, F SCHENECTADY, NEW YORK,- ASSIGNOR TO SCENECTADY VABNISH COMPANY, OF SCHENECTAIJY, NEW YORK, A CORPORA- TION OF NEW YORK COMPOSITION No Drawing. 7

10 lating material, such as paper, vegetable or animal fabric, arcing frequently results between difi'erent coils, due to corrosion of the insulation, and difference in potential between'the coils. While the oil in which the transformers are immersed is a cooling and insulating medium, nevertheless, such oil has frequently been found to contain materials rendering it conductive or to have had its chemical constitution so changed that it will allow an arc to jump from one transformer coil to another. Where, as stated, the insulation about the conductors has decayed and there exists a difierence in potential between the one or more ad'acent transformers, the oil may be of such c aracter as topermit of arcing, and thus destroy the efficiency of the transformers.

The difficulty heretofore has been to find a material which would not be dissolved by mineral oils in oil cooled transformers. As is well known, these transformers run at a considerable temperature rise, and it is essential that the insulation of the coils be 5 insoluble in the hot mineral oil. The proper cooling of the transformers depends on the rapidity "of circulating of the oil in thetransformer tank surrounding the coils. Where the insulation is soluble, the oil becomes heavy 40 and the circulation of the oil impeded.

Hence the cooling of the coils is not as efficiently done as when the oil is thinner, and the temperature rise of the machine consequently higher and its electrical capacity lower.

sist in maintaining the conductor always Applieation flled October 13, 1927. Serial No. 228,035.

properly insulated so as to prevent the possibility of arcing. Y

A very important object of this invention is therefore the provision of an oilproof coating composition which is not only insulating but which is moreover insoluble in the hot or cold oil surrounding the transformer.

this manner, the circulating efliciency of the oil is increased and no objectionable chemical compounds are formed.

A further obj not of the invention is to provide a composition of this character which may be prepared in liquid form, or prepared in liquid form, permitted to solidify and then subsequently rendered fluid for impregnation and coating purposes.

The invention has, moreover, in mind the production of a plastic which may be suitably shaped or moulded and also rolled, and

.when cooled is a hard solid substance of nice appearance, non-conductive and waterproof.

The composition of the'present invention comprises preferably a resin such as rosin, colophony or abietic acid. I have found, however, that resins containing gums, ethereal oils and other important constituents may be employed, and in fact any resinous material may be utilized in accordance with requirements and the product desired.

With the resin, I preferably mix or combine a natural gum which is a species of Xanthorrhoea. One of such gums which I have used is accroides or acaroids of which there is an abundant and cheap supply obtainable from Australia.

There are two kinds of gum accroides both characterized by being esters of paracoumaric acid.

Other species of Xanthorrhoea may be employed in accordance with the product desired, but I Will here set forth the red and yellow gum'accroides.

Red accroides comprises paracoumaric acid (C H O 1%; bcnzoic acid in traces and paracoumaric acid 2%, both in combination with erythrocsinotannol (C H Q OH) paraoxybenzaldehyde 15%. The bung-85%, consists of the erytllroresinotannol ester of paracoumaric acid. The absence of cinnemic acid distinguishes this resin from yellow acaroid.

The yellow acaroids comprise free paracoumaric acid (0 11 0 4%; free cinnamic acid .5%; combined paracoumaric acid 7% and combined cinnamic acid. 6%. Both acids form esters with xanthroresinotannol producing chiefly the corresponding ester of paracoumaric acid which forms the main constituent of this resin.

Also there are probably present styracin (0 E 0 cinnamic phenylpropyl ester, paraoxybenzaldehyde, and possibly vanillin.

To this mixture may be added vegetable, animal and mineral oils, or other resins, both natural and synthetic, for instance, the prod uct known commercially as paracumaron. However, the resin and gum are the fundamental ingredients, and the other substances may or may not be added, as desired.

The proportion of the ingredients is determined by the melting point of the finished compound desired. This melting point varies for most purposes from 100 C. to 150 C. in accordance with the particular type of coil or conductor to be treated.

The difference in the melting points may be easily obtained by using a greater or less amount of each ingredient in the mixture, it being found that a composition consisting of equal parts of the two materials will suliice for a large number of cases.

It has been found useful in some instances to add to the mixture other materials for instance, castor oil or fatty acids in the nature of stearic acid and other resins of both natural and synthetic character. These substances may be added singly to a mixture of rosin and gum accroides or in some cases both stearic acid and castor oil may be used, or these two ingredients together with other resins may be employed. Also either stearic acid or castor oil may be employed in conjunction with such other resins in accordance with requirements of a particular case.

The castor oil and other oils for instance, serve to reduce the brittleness of the resin and accroides composition, while stearic acid acts in some cases as a flux to give a better combination of the two main ingredients with or withoutthe castor oil or other resins.

The use of resins natural or synthetic, for example, paracumaron, is useful at times for varying the melting point of the i'OIHPOSltion and for determining its solubility in connection with various types of transformer oils.

For example the mixture may comprise:

Rosin, gum accroides, castor oil.

Rosin, gum accroides, stearic acid.

Rosin, gum accroides, castor oil, stearic acid.

Rosin, gum accroides, resins (natural or synthetic) Rosin, gum accroides, stearic acid, resins (natural or synthetic).

Rosin, gum accroides, castor oil, resins (natural or synthetic).

Rosin, gum accroides, stearic acid, castor oil, resins (natural or synthetic).

As previously stated, for a great number of instances, a plain mixture of gum accroides and rosin in equal parts will suilice and the proportions of these constituents may be varied to change the melting point. The melting point may be changed for example by adding a greater or smaller amount of rosin.

Where a single one of the ingredients above noted is employed, they may comprise up to approximately ten per cent (10 of the mixture.

For instance, in the use of castor oil or resins ten per cent (10%) of the mixture has been found suliicient. In the case of stearic acid, the amount found necessary for the best result is approximately five per cent- (5%). \Vhere the ingredients are employed together, their total proportion should be substantially ten per cent (10%) of the mixture.

Of course, a quantity more or less may be useful in accordance with the character of rosin, and the nature of the gum, and the percentage of proportions here recited are those.which have been found experimentally and practically satisfactory with a wide.

range of ingredients and applications.

In preparing my improved oil-proof and waterproof composition, the gum accroides and rosin together with the addition ingredients, if employed, may be melted together or separately, and mixed in flue-d condition to the proper consistency, and the fluid strained and permitted to cool into a hard solid compound having a melting point from 100 C. to 150 C., more or less. By having the product in solid form, it may be easily transported and employed as desired.

In treating transformer coils or for other impregnation purposes, a series of tanks of suitable size are employed. In one of the tanks, the composition of the present invention is placed and melted to a fluid condition, say at a temperature of approximately 325 F. The other tank receives the coils and is preferably provided with means for exhausting air therefrom, being in the nature of a closed container.- After the air has been exhausted, the coil contained in the chamber is heated to expel any moisture. Thereafter, the melted material in the other tank is passed into the chamber containing the article to be treated, and the article immersed in the treating substance.

Pressure is then applied in the closed chamber containing the coil or other article great variety of applications where a grease-.

immersed in the composition of my invention, and such pressure is maintained for a sufficient time to force the compound into the di-electric covering of the coils or article to be impregnated. There results a hard coating thoroughly oilproof and insoluble in the hot or cold oil surrounding the transformer.

As previously stated, the ingredients of 0 my composition are preferably melted together until the proper consistency or degree of plasticity is reached, such that a uniform product may be obtained, and thereafter permitted to cool int-o solid form.

This is the finished article which is utilized in the impregnating process just described. My invention is obviously useful for a proof or waterproof impregnation compound is desirable. For example, the ingredients herein recited may be dissolved in alcohol, petroleum, naphtha, menthanol and a variety of other solvents, or two or more of these solvents may be used together.

This solution so obtained may be applied to asurface to be treated by means of spraying, brushing, dipping or other mechanical process, and it has been found under such circumstances that a hard insoluble impregnation and protective coating is produced.

It will be understood, of course. that a great variety of vegetables, animal and mineral oils other than castor oil may be used as the addition ingredients of my invention, as well as resins of various types, both natural and synthetic.

In referring to the use of paraclnnaron, it will be understood that I have in mind a resin having this commercial trade name. or a resin having the formula C H O. I also have in mind the use of commercial cumaron which is a mixture of paracumaron and para indene. These materials may be used in combination with a resin or with fatty acids such as castor oil and stearic acid, as previously described. It Will be understood, however, that the composition so obtained is not the full equivalent of the natural gum accroides and resin, although it may be used for the same purpose. I have also found that paracumaric acid combined with a resin has excellent oil proofing qualities, but the results are not as good as a composition of rosin and gum accroides, as described.

My composition is a non-conductor. and in some cases may be employed solely as the insulating material or impregnating agent.

In other cases, as for example, electrical applieations, it may be used to impregnate the di-electric or insulator and to afford not only a greater insulation, but a protection to the first coating, which will prevent its decay or corrosion, due to the action of either the atmosphere or as in the case of transformer coils, the action of the oil in which such coils are usually immersed, tending to dissolve it. It must, morover, be understood, that since 'I obtain a solid product, this product is available in its solid form for a great variety of purposes where an insulating or waterproof material is desirable, and the solid product may be shaped, if preferred, and sawed or cut to any desired form, for example, while the composition is cooling after a proper mixture is obtained, such cooling may be accomplished in a suitable mold, or the material may be rolled into sheets. The present invention is not limited, therefore, to a coating or impregnating compound, although the composition is especially useful in this connection, since, obviously, it may be used in its solid form for an innumerable number of purposes, meeting requirements for which it is characteristically useful.

It will be understood that in some cases the materials may be placed in a tank adjacent to the article to be treated, and there and then propelled or transported to the treating chamber. This step would be desirable in some operations, and would eliminate the necessity of awaiting the cooling of the mi Xturc to solid form.

In making a plastic composition, which can be rolled into sheets and cut to suitable sizes and shapes or moulded to various shapes, it may be desirable to add a hardening agent, and for this purpose any well known material may be used. Of course, heat and pressure either together or separately may be employed, depending, of course, upon the nature of the composition.

I claim:

1. In the art of treating electrical coils having a covering and adapted to be immersed in a cooling medium such as oil, the step which comprises impregnating the coverin of such coils with a composition insoluble in the oil comprising an accaroid resin.

2. In the art of treating electrical coils having a covering and adapted to be immersed in a cooling medium such as oil, the step which comprises impregnating and coating the covering with a composition insoluble in the oil comprising an accaroid resin, the said composition forming a hard coating about the coils.

3. In the art of treating electrical coils having a covering and adapted to be immersed in a cooling medium such as oil, the step which comprises impregnating the covering with a composition insoluble in the oil comprising an accaroid resin and a pure resin.

4. In the art of treating electrical coils having a covering and adapted to be immersed in a cooling medium such as oil, the step which comprises impregnating and coating such covering with a composition insoluble in the oil comprising an accaroid resin melted and mixed to the desired consistency, 7

and a pure resin, the said composition forming a hard coating about the coils.

5. In the art of treating electrical coils having a covering and adapted to be immersed in a cooling medium such as oil, the step which. comprises impregnating such covering with an insulating composition insoluble in oil comprising an accaroid resin, rosin and one or more agents in the nature of castor oil, stearic acid, and another resin.

6. In the art of treating electrical coils having a covering and adapted to be immersed in a cooling medium such as oil, the step which comprises impregnating and coating such covering with an insulating composition insoluble in the oil comprising an accaroid resin, rosin and one or more addition agents in the nature of castor oil, stearic acid and anotherresin, the said composition forming a hard coating about the coils.

7. In the art of treating electrical coils having a covering and adapted to be immersed in a cooling medium such as oil, the step which comprises covering such coils with an insulating composition comprising an accaroid resin and a plasticizer.

8. In the art of treating electrical coils having a covering and adapted to be immersed in a cooling medium such as oil, the step which comprises covering such coils with an insulating" composition comprising an accaroid resin, rosin and a plasticizer.

9. In the art of treating electrical coils having a covering and adapted to be immersed in a cooling medium such as oil, the step which comprises coating such coils with an insulating composition comprising an accaroid resin, rosin and a plasticizer and flux.

10. An electrical coil impregnated and coated with an oil proof and water proof composition comprising an accaroid resin and forming an insoluble coating about the coil.

In testimony whereof I have hereunto set my hand.

WILLIAM H. WRIGHT.

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