Patent ID: 6869425

Claim:
A process for regulating fluid flow through flexible tubing in a peristaltic pump where a length of the tubing which has been peristaltically deformed recovers to its original cross-sectional configuration at a rate dependent upon the temperature T f of the fluid at the interior surface of the tubing, said process comprising the steps of: (A) determining a temperature T s by measurement with a first temperature sensor disposed on a heat transfer path adjacent to an exterior surface of said tubing, the heat transfer path being defined by a thermally conductive electrical insulator having a first surface disposed against said exterior surface of said tubing in said pump and a second surface bonded to said first temperature sensor by an interposed thermally conductive layer of bonding material; (B) determining the ambient temperature T a by measurement with a second temperature sensor disposed in said pump at a location thermally isolated from said heat transfer path; (C) periodically calculating the temperature T f of the fluid at the interior surface of the tubing according to the formula T f = ( b ⁢ ⁢ T a ) - T s ( b - 1 ) where b is an empirically predetermined constant equal to (T f −T s )/(T f −T a ) calculated from a measured value of the temperature T s when both temperatures T f and T a are fixed at selected values; and (D) varying the pump operating speed inversely with, and as a function of, changes in the calculated temperature T f .