Opinion ID: 525267
Heading Depth: 4
Heading Rank: 1

Heading: at least two similar thermally and physically separated resistive electrical conductors;

Text: 17 (b) each of said conductors having a length at least equal to the largest cross section dimension of the conductor; 18 (c) each of said electrical conductors including a hollow electrically non-conductive refractory cylindrical substrate supporting body extending the length of the conductor, and a conductive resistance film having a non-zero temperature coefficient adhered to the outer surface of the substrate body and extended over the length of the substrate body; 19 [ (c) ] (d) a thermo insulating bridging means operatively disposed between, and closing the gap between said electrical conductors over the length of the conductors, thereby preventing connected flow around one conductor independent of the other conductor, the [major] overall shape of the sensor being figure eight in cross section, [defined by the conductors and not by the bridging means,] with [each] the conductors being [conductor] exposed to ventilation over at least a majority of [its] their surface, and with the conductor pair cross section itself used to define the fluid dynamic cross section of a figure eight cross section which is exposed to the fluid stream where the resulting local stagnation region caused by impinging flow at its point of separation against an electrical conductor is therefore small with respect to the conductor cross section, each conductor exhibiting a change in electrical resistivity as a function of temperature; and, 20 (e) each of said electrical conductors being provided with electrical connection means, whereby each electrical conductor can be electrically heated by an electrical current passing through each conductor. 21 EII argued in accompanying remarks that the amendment to the newly designated clause (d) overcame the Sec. 112 rejection. EII also argued that this amendment overcame the Sec. 102 rejection on Hayakawa: 22 Claim 1 furthermore defines over the Hayakawa structure by defining that the insulating bridge means closes the gap between applicant's conductors so as to provide the overall figure-eight in cross section shape of the sensor, and such structure is not taught or suggested by Hayakawa whose overall structure is determined by his support member 2 in Fig. 1(A) through 1(E). 23 The claim as amended satisfied the examiner, he withdrew his rejections, and allowed the claim. 24 The district court concluded that in view of the prosecution history, claim 1 should be construed to encompass only the figure eight cross-sectional configuration. The court then held that there was no infringement by equivalents because the Sutron sensors have a racetrack, or oval configuration, not a figure eight configuration. The district judge drew a picture of his concept of the accused Sutron sensor in cross-section in his published opinion, 688 F.Supp. at 212, 8 USPQ2d at 1901, q.v. 25 We think the district court's sole error in discussing infringement was its statement, with reference to Graver Tank & Manufacturing Co. v. Linde Air Products Co., 339 U.S. 605, 70 S.Ct. 854, 94 L.Ed. 1097 (1950), that the doctrine of equivalents is not designed to permit a patent to exceed the scope of its claims. The Supreme Court said a number of things in Graver Tank, but that was not one of them. The essence of the doctrine of equivalents is that it permits recovery for infringement where the accused device does not fall within the literal scope of the claims and is, therefore, outside their literal scope. 26 As to result, we think the district court properly estopped EII from asserting that the accused sensors infringe under the doctrine of equivalents. We have made, in accordance with our precedent, e.g., Mannesmann Demag Corp. v. Engineered Metal Products Co., 793 F.2d 1279, 1284-85, 230 USPQ 45, 48 (Fed.Cir.1986), an inquiry as to what was surrendered during prosecution and why. EII made two significant changes in the claim in the second amendment. First, EII replaced the phrase the major shape of the sensor being defined by the conductors and not by the bridging means, with the phrase the overall shape of the sensor being figure eight in cross section. Second, EII emphasized that the conductor pair cross section itself defines the fluid dynamic cross section of a figure eight cross section by the insertion of the quoted phrase. When EII added these figure eight limitations it argued that they overcame the Sec. 102 and Sec. 112 rejections. To overcome the former would be a predicate to overcoming the Sec. 103 rejection, so the figure eight limitations were asserted to overcome that rejection too, albeit indirectly. Thus, the reasons for the amendment were to overcome: (1) the Sec. 102 rejection; (2) the Sec. 103 rejection, and (3) the Sec. 112 rejection. The first two reasons, the amendment itself, and the examiner's allowance of the claim, convince us that the figure eight limitations fall on the highly limiting end of the spectrum of limiting effect. See Hughes Aircraft Co. v. United States, 717 F.2d 1351, 1363, 219 USPQ 473, 481 (Fed.Cir.1983). That a second, concurrent amendment was made, and that the figure eight limitations made the claim more definite, do not alter our conclusion. On these facts, we think the district judge was right to limit EII to a reading of figure eight that does not cover the accused sensor having the racetrack or oval configuration. Cf. Exhibit Supply Co. v. Ace Patents Corp., 315 U.S. 126, 135-37, 62 S.Ct. 513, 518-19, 86 L.Ed. 736, 52 USPQ 275, 279-80 (1942); Prodyne Enterprises, Inc. v. Julie Pomerantz, Inc., 743 F.2d 1581, 1583, 223 USPQ 477, 478 (Fed.Cir.1984). See also LaBounty Mfg., Inc. v. United States Int'l Trade Comm'n, 867 F.2d 1572, 1575-76, 9 USPQ2d 1995, 1998-99 (Fed.Cir.1989), and Loctite Corp. v. Ultraseal Ltd., 781 F.2d 861, 870, 228 USPQ 90, 96, note 7 (Fed.Cir.1985). We therefore affirm the finding of no infringement by application of the doctrine of equivalents.