Opinion ID: 775530
Heading Depth: 3
Heading Rank: 1

Heading: A gas log fireplace comprising in combination:

Text: 7 a housing having a top wall, bottom wall, side walls and a rear wall; 8 a firebox within the housing comprising a top wall, rear walls and side walls, said firebox forming a primary combustion chamber; 9 a room air plenum comprising a top room air plenum between the top wall of the firebox and the top wall of the housing, a rear room air plenum between the rear wall of the firebox and the rear wall of the housing in communication with the top room air plenum; 10 an inlet opening for allowing room air to enter the rear room air plenum; 11 an outlet opening in communication with the top room air plenum for allowing room air and exhaust products in the top room air plenum to be exhausted into a room in which the fireplace is situated; 12 an intake opening into the firebox for receiving room air into the primary 13 combustion chamber; 14 a burner within the firebox, at least one artificial log within the firebox adjacent to said burner and means for supporting said at least one log within the firebox; 15 means for delivering a source of combustible gas to the burner; 16 an exhaust opening in the top wall of the firebox; 17 a catalytic converter positioned in the exhaust opening of the firebox and forming a secondary combustion chamber; and 18 whereby exhaust products from the primary combustion chamber are received by the catalytic converter wherein secondary combustion takes place and the exhaust products from the secondary combustion chamber are received by the top room air plenum and are mixed with room air received by the rear room air plenum and exhausted into the room in which the fireplace is situated. 19 '534 patent, col. 5, l. 41 - col. 6, l. 32 (emphasis added). The dispute in this appeal focuses on the emphasized term rear walls, in the firebox limitation above. This plural term was changed to the singular term rear wall in Superior's certificate of correction, as explained below in the section entitled Procedural History of Litigation. Before explaining the litigation, however, we document the events that led to the '534 patent being issued with the term rear walls. 20 In the course of prosecuting the patent application, Superior submitted an amendment adding a new claim that eventually issued as claim 1. This claim initially recited rear wall in the firebox limitation. 21 On February 14, 1997, Superior representatives met with the examiner and agreed to certain changes to the claims. The changes agreed to during this meeting are set forth in an Examiner Interview Summary Record. That summary does not show any change to the rear wall limitation. 22 On March 6, 1997, the examiner and a representative for Superior followed up the earlier meeting with a telephonic interview. During that interview the parties discussed a reference that the examiner had discovered subsequent to the February 14 meeting. This interview was also memorialized with an Examiner Interview Summary Record, mailed on March 11, 1997, in which the examiner stated that the claim in question would be modified as set forth in the attached examiner's amendment. That amendment shows, among other changes, that rear wall was amended to rear walls. That is the first point chronologically in the prosecution history that shows such a change. A Notice of Allowability was also mailed on March 11, 1997, thus indicating that the amended claim-with the revised expression rear walls-was allowable. 23 The examiner's amendment also reminded Superior that [s]hould the changes and/or additions be unacceptable to applicant, an amendment may be filed. Superior did submit an amendment under 37 C.F.R. 1.312 (section 312 amendment) three months later, on June 11, 1997, making at least forty separate changes to the specification. This amendment, however, did not amend the claim term rear walls, and Superior submitted no further amendment before issuance. Consequently, the '534 patent issued with the term rear walls on October 21, 1997. After the patent issued, Superior identified another nine errors and, on August 28, 1998, submitted a Make-of-Record Letter noting these errors. The Make-of-Record Letter did not list any amendments to the claim term rear walls. 24 Superior alleges that the prosecution history does not contain the whole story. According to Superior, prior to the March 6 interview the examiner edited the claim in question and faxed to Superior the edited claim. This edited claim does not appear in the prosecution history. These edits, according to Superior, were made by the examiner not to effect any substantive change but merely to facilitate consideration of the newly discovered reference by showing reference numerals, corresponding to features of the reference, after each of the limitations of the claim in question. According to Superior, however, the faxed, edited claim also changed rear wall to rear walls. Superior asserts that it marked up the faxed, edited copy of the claim to show the amendments that Superior authorized during the March 6 interview. Superior's mark-ups are silent with regard to the change from rear wall to rear walls. That is, the mark-ups do notdelete the s in rear walls nor question the change in any way. Based on this silence, Superior insinuates that the addition of the s to rear wall was never authorized. 25 Although not discussed by Superior, it is clear that the examiner's amendment made additional changes to the claim that are not reflected in Superior's mark-up. Thus, Superior's alleged mark-up was not the final version of the claim, as issued.