Manville Boiler Company, Incorporated v. Columbia Boiler Company of Pottstown, Incorporated, and Columbia Boiler Company, Incorporated

HAYNSWORTH, Circuit Judge.

This is a patent case involving the usual defenses of invalidity and noninfringement. Upon proof that was largely documentary or undisputed, the District Judge was persuaded that both defenses were meritorious and he filed appropriate findings of fact and conclusions of law. We take a different view.

The patent involved, Mandelburg No. 2,633,107 issued in 1953, covers a modification of the Stauffer design for domestic boilers so as to permit the use of a circular rather than an oval stack outlet and to provide a variable, automatic damper permitting flue gases to be…