WESTINGHOUSE ELECTRIC & MFG. CO. v. AMERICAN TRANSFORMER CO.

(Circuit Court, D. New Jersey. May 10, 1904)

1. PATENTS-ELECTRICAL CONVERTERS-INFRINGEMENT.

Claim 4 of letters patent of the United States No. 366,362, dated July 12, 1887, issued to George Westinghouse, Jr.. for "improvements in electrical converters", sustained, and held not infringed.

2. SAME.

The two rectangular coil openings shown in the drawings and description of the converter are not "open spaces in its core" within the meaning of claim 4.

(Syllabus by the Court.)

In Equity.

See 121 Fed. 560.

Drury W. Cooper and Thos. B. Kerr, for complainant.
C. V. Edwards, for defendant.

BRADFORD, District Judge. The Westinghouse Electric and Manufacturing Company has brought its bill against the American Transformer Company, charging infringement of letters patent of the United States No. 366,362, dated July 12, 1887, issued to George Westinghouse, Jr., and by him assigned to and now held and owned by the complainant. The patent relates to improvements in electrical converters, now usually called transformers. Heat, representing loss or waste, or, in a strict sense, conversion, of electric energy, is generated or developed in the coils and core of a transformer when in use. In the coils, it is due to the resistance of the copper to the electric current carried by them, and, in the core, it is due to eddy currents, and hysteresis attendant upon the reversals of polarity of the magnetic flux in the core, or, in other words, the magnetization and demagnetization of the core in rapid succession. Heat increases with the size and capacity of the transformer, lessening its efficiency by reducing the conductivity of the coils and augmenting the hysteretic losses in the core, and, if excessive, impairs not only the efficiency but the durability and safety of the apparatus. Hence, it is important that the temperature of the coils and core should not be allowed to rise materially above the proper point, which has been stated to be about 75° centigrade. It appears that where the capacity of the transformer is small, not exceeding five or ten kilowatts, no special provision is necessary in order to get rid of an excess of heat, as the coils and core will remain sufficiently cool through radiation into the surrounding air. Where, however, the transformer has a capacity exceeding ten kilowatts it is necessary to make special provision to avoid an undue increase in temperature. For this purpose oil, or possibly some other suitable liquid, has been used. The transformer is placed in an inclosing metal case filled with oil. When so immersed any excess of heat, within certain limits determined by the size and capacity of the transformer, is dissipated by being carried through conduction and convection from the coils and core to

the inclosing-case and thence by radiation. For present purposes it is unimportant, where the heat is beyond those limits, to consider methods by which the proper temperature best may be maintained. The patent in suit covers particular means for preventing the overheating of transformers. The patentee thus states the general nature and object of his invention:

"The invention relates to the construction of a class of apparatus employed for transforming alternating or intermittent electric currents of any required character into currents differing therefrom in certain characteristics. Such apparatus are usually termed induction coils' or 'converters.' The object of this invention is to provide a simple and efficient converter which will not become overheated when employed for a long time in transforming currents of high electro-motive force, and which will be thoroughly ventilated."

The drawings of the patent represent respectively a cross section and a longitudinal section of a converter or transformer. They are as follows:

With respect to these drawings and in describing the invention the patentee says:

"Referring to the figures, A represents the core of the converter, and C1 and C2 the respective coils. The core is preferably composed of thin plates of soft iron a a, separated individually or in pairs from each other by thin sheets of paper or other insulating material. This insulating material is preferably applied to one surface of the plates by being glued or pasted thereto, and these surfaces may lie all in the same direction, thus separating the plates individually, or alternate plates may have their covered surfaces in one direction and the intervening plates have their covered faces in the opposite direction, thus magnetically separating the plates in pairs. The plates are preferably constructed with two rectangular openings e1 and e2, through which the wires pass. For convenience in inserting the coils, or rather in applying the plates to the coils after the latter have been wound, a cut is made from each opening, as shown at b b. By bending the ends cc upward the plates may then be thrust into position, and the ends c c then close about the coils. The tongues es of succeeding plates are preferably inserted from opposite sides. I do not, however, herein broadly claim an induction-coil having its core constructed of thin plates formed in the manner just described; but such invention is claimed in an application of even date herewith, filed by Albert Schmid. Each group of-say five or sixplates thus applied is preferably separated from the succeeding group by air-spaces. These may be produced by passing tubes f1 f1, which may be of

soft iron or other metal, or of vulcanized fiber, along the lengths of the plates. It may be sufficient in other instances to block the groups of plates apart at intervals instead of extending the tubes the entire length. Preferably, also, the primary and secondary coils C1 C2 are separated from each other in a similar manner. In his instance blocks or tubes f2, of non-conducting material, are used. The tubes may be perforated, as shown at f3 f3. Where the converter is to be used in open air, the tubes f1 and f2 would permit a free circulation of air, and thus aid in keeping the converter cool. It may be preferred in some instances to surround the converter with some oil or paraffine or other suitable material, which will assist in preserving insulation and will not be injured by heating. This material when in a liquid form circulates through the tubes and the intervening spaces of the coils and plates, and preserves the insulation, excludes the moisture and cools the converter. The entire converter may be sealed into an inclosingcase, H, which may or may not contain a non-conducting fluid or a gas."

While the patent in suit contains five claims the charge of infringement has been restricted to claim 4. It is as follows:

"4. The combination, substantially as described, of an electric converter constructed with open spaces in its core, an inclosing-case, and a non-conducting fluid or gas in said case adapted to circulate through said spaces and about the converter."

This claim has been the subject of litigation elsewhere and adjudged valid. It was upheld by Judge Hazel in Westinghouse Electric & Mfg. Co. v. Union Carbide Co. (C. C.) 112 Fed. 417, and, on appeal, by the court of appeals for the second circuit, 117 Fed. 495, 55 C. C. A. 230. It was also recognized as valid by Judge Adams in Westinghouse Electric & Mfg. Co. v. Wagner Electric Mfg. Co., 129 Fed. 604. Its validity within the limits of a proper construction is admitted here; the whole contention at the hearing being directed to the question of infringement. Most, if not all, of the elements of the combination of claim 4 were old in the art, but the combination itself was new. It has proved of great utility and must, in my judgment, be accorded patentable novelty.

It appears that after the complainant became the owner of the patent in suit and prior to the filing of the bill the defendant manufactured and sold a number of transformers, designed to be used in cases filled with oil, and having space blocks between their core plates. Their construction is shown by complainant's exhibit A. They admittedly infringed claim 4. Upon the bringing of the patent in suit to the attention of the defendant, however, the space blocks were removed from between the core plates, and the spaces in which they had been inserted were filled. And the complainant by stipulation of record on the second day on which evidence was adduced in this case released the defendant from all claims for damages or profits arising from the above mentioned infringement. It further appears that the defendant has not since that infringement manufactured, sold or used any transformer similar to that shown in exhibit A, and that it neither threatens nor intends such manufacture, sale or use. The construction so admitted to infringe had parallel primary and secondary coils, and a core composed of thin plates of soft iron arranged in groups separated from each other by blocks, whereby spaces between the groups were provided; the coils and core being inclosed in a metal case containing oil, which, when the transformer was in

The

use, circulated through the open spaces in the laminated core. construction now complained of differs from that shown and described in the patent in suit, and from that just referred to, in that the lamina or plates of the core are not separated into groups, with intervening spaces through which oil, paraffine or other suitable liquid or fluid may circulate. The elements of the combination of claim 4 are, first, an electric converter; second, open spaces in its core; third, an inclosing-case; and, fourth, a non-conducting fluid. or gas in said case adapted to circulate through said spaces and about the converter. Has the defendant's transformer "open spaces in its core" in the same sense in which those words are employed in claim 4? If it has not, it lacks an essential element, and the charge of infringement with respect to it must fall. It has a solid core, unless, indeed, the two rectangular openings for the coils properly can be considered "open spaces in its core." But spaces between the core as a whole and the coils should not be confounded with spaces in the core. The core of the transformer is so constructed as to leave the rectangular openings for the reception or accommodation of the coils. It is made of such form as to surround them. Were it not for coil openings the plates could not constitute the core of a transformer of the general type shown in the patent in suit. The core is perfect and complete irrespective of the presence or absence of coils in its openings. In its entirety and by its necessary construction a core of the type of transformer under consideration has coil openings. Neither a coil opening nor any part of it can legitimately be held to be an open space in the core within the meaning of claim 4. I find nothing in the claims, description or drawings of the patent in suit at variance with this conclusion, but, on the contrary, much to fortify it. Nowhere in the drawings or description is a coil opening, in whole or in part, designated or referred to as a space in To ascertain the true meaning of the words "open spaces in its core" as used in claim 4 regard must be had to the general character of the invention. Its object was to prevent the overheating of the coils and core, and Westinghouse proposed to accomplish it by providing an intervening space between the primary and secondary coils, and by opening up spaces in the core itself in such manner as to expose to the oil or other surrounding medium a heat-dissipating surface of large area. The open spaces in the core thus designed were spaces which would not exist, were it not for the desired cool ing of the core. The only open spaces in the core shown in the description or drawings are those produced by the insertion of tubes or blocks between groups of core plates. The patentee states that the drawings represent longitudinal and cross-sections of "a converter. involving the features of the invention." Tubes are disclosed in the drawings, but not blocks. Blocks, however, are treated as the equivalent of tubes, for the patentee, referring to the spaces between the groups of plates, says:

"These may be produced by passing tubes f1 f1, which may be of soft iron or other metal, or of vulcanized fiber, along the lengths of the plates. It may be sufficient in other instances to block the groups of plates apart at intervals instead of extending the tubes the entire length."

It is further stated:

"Each group of-say five or six-plates thus applied is preferably separated from the succeeding group by air spaces."

While it is said that the groups are "preferably separated" the fact remains that the only open spaces in the core, described or disclosed, are those produced by separating or dividing its laminæ into groups. The patentee further says:

"Preferably, also, the primary and secondary coils C1 C2 are separated from each other in a similar manner."

The statement that the surrounding medium "when in a liquid form circulates through the tubes and the intervening spaces of the coils and plates" manifestly refers, on the one hand, to the spaces intervening between the primary and secondary coils which "are separated from each other in a similar manner," and, on the other, to the spaces intervening between separated groups of core plates, but not to spaces between the core as a whole and the coils. Be this as it may, however, the "spaces" of claim 4 are "open spaces in its core. The "open space" of claim 1 is that intervening between "parallel primary and secondary coils." The combination of claim 2 has as its elements, first, primary and secondary coils, second, a core composed of lamina of soft iron arranged in groups and, third, “open, spaces" separating said groups. This claim, aside from the coils, specifically refers to the construction of the core, but lacks the elements of "an inclosing case" and "a non-conducting fluid or gas in said case adapted to circulate through said spaces and about the converter," included in the combination of claim 4. The elements of the combination of claim 3 are, first, a core composed of soft iron plates arranged in groups and, second, "open tubes" intervening. This claim specifically refers to a particular construction of the core, but, like claim 2, lacks two of the elements of claim 4. Claim 5 includes the following elements: first, primary and secondary coils, second, a core composed of magnetically separated laminæ of soft iron arranged in groups, third, "air spaces" separating the different groups from each other and, fourth, the arrangement of the laminæ of the several groups in different parallel planes. This claim also specifically refers to a particular construction of the core, but, like claims 2 and 3, lacks the same two elements of claim 4. In the combination of claim 4 "open spaces in its core" as well as an "inclosing-case" and a "non-conducting fluid or gas" therein, are "substantially as described." No doctrine of equivalency can dispense with the open spaces in the core of the transformer, for they are a necessary element of the combination. Without them the claim cannot be satisfied. Open spaces might be produced in the core other than those specifically set forth in the drawings or description, which would be the equivalent of the latter. The core itself might, for instance, be cut into in various directions in such manner as to expose what may be termed internal heat-dissipating surfaces to the oil or other medium surrounding the transformer, and in such case, the other requirements of the combination being satisfied, infringement could be found. But the essence of the first element of the claim insisted on