Parker v. Flook

Citation: Parker v. Flook, 437 U.S. 584, 198 U.S.P.Q. (BNA) 193 (1978).

Factual Background
The application, entitled “Method for Updating Alarm Limits,” involved a method for updating alarm limits during catalytic conversion processes in an oil refinery. The method consisted of three steps: an initial step, which measured the present value of the process variable (e.g., the temperature); an intermediate step, which used an algorithm to calculate an updated alarm limit value; and a final step, which adjusted the alarm limit to the updated value. The difference between conventional methods of changing alarm limits and that described in Flook’s application was in the intermediate step &mdashj;a mathematical algorithm.

The patent examiner rejected the claims as being addressed to nonstatutory subject matter, since the only novel part of the invention was the algorithm used to adjust the alarm value. The Board of Appeals sustained the examiner’s rejection. The C.C.P.A. reversed, reasoning, inter alia, that since the mere solution of the algorithm would not constitute infringement of the claims, a patent on the method would not pre-empt the formula used. The C.C.P.A. narrowly interpreted In re Christensen as limited to situations where there were no steps other than those required for the solution of the algorithm. The C.C.P.A. concluded that because there was some post-solution activity (i.e., the use of the algorithm to obtain a given result), the claims involved patentable subject matter.

Supreme Court Decision
The U.S. Supreme Court reversed the C.C.P.A.’s decision, holding that the identification of a limited category of useful, though conventional, post-solution applications of the formula or algorithm does not make the method eligible for patent protection under 35 U.S.C. §101. The Court, citing O’Reilly v. Morse, reasoned that Flook’s formula was within the prior art and thus not patentable, since the chemical processes involved in catalytic conversion are well known, as are the monitoring of process variables, the use of alarm limits to trigger alarms, the notion that alarm limit values must be recomputed and readjusted, and the use of computers for automatic process monitoring.