Westinghouse Electric & Manufacturing Co. v. American Transformer Co.
Decision Date | 10 May 1904 |
Citation | 130 F. 550 |
Parties | WESTINGHOUSE ELECTRIC & MFG. CO. v. AMERICAN TRANSFORMER CO. |
Court | U.S. District Court — District of New Jersey |
Syllabus by the Court
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.
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.
Drury W. Cooper and Thos. B. Kerr, for complainant.
C. V Edwards, for defendant.
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 75o 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 drawings of the patent represent respectively a cross section and a longitudinal section of a converter or transformer. They are as follows:
(Image Omitted)
With respect to these drawings and in describing the invention the patentee says:
While the patent in suit contains five claims the charge of infringement has been restricted to claim 4. It is as follows:
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 F. 417, and, on appeal, by the court of appeals for the second circuit, 117 F. 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 F. 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 oil 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 use, circulated through the open spaces in the laminated core. The construction now complained of differs from that shown and described in the patent in suit, and from that just referred to, in that the laminae 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...
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Westinghouse Electric & Mfg. Co. v. Wagner Electric & Mfg. Co.
...& Mfg. Co. v. Union Carbide Co., 117 F. 495, 55 C.C.A. 230; Westinghouse Electric & Mfg. Co. v. American Transformer Co. (C.C.) 121 F. 560, 130 F. 550. evidence clearly shows, we think, that the thing principally to be desired in the construction of a transformer is to keep the coils, rathe......
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Westinghouse Electric Mfg. Co. v. Wagner Electric Mfg. Co.
...Union Carbide Co., 117 F. 495 (55 C.C.A. 230); Westinghouse Electric & Mfg. Co. v. American Transformer Co. (C.C.) 121 F. 560; Id. (C.C.) 130 F. 550.' Supreme Court of the United States considered the case on certiorari. 225 U.S. 604, 32 Sup.Ct. 691, 56 L.Ed. 1222, 41 L.R.A. (N.S.) 653. Thi......