Patent ID: 6178291
Filing Date: 2001-01-23
Classification: F24H,G05D

Abstract:
A control system for a fluid heater including a housing having an inlet and an outlet, at least one fluid pathway through the housing, and a heating element proximate the fluid pathway for heating an operating fluid flowing through the pathway, the control system comprising:an inlet temperture sensor for determining the temperature of the operating fluid at the inlet;a flow sensor for determining the rate of operating fluid flow through the fluid pathway;a switching device connected between a source of electrical power and the heating element; anda controller in communication with the temperature sensor, the flow sensor, and the switching device, the controller includingfirst means for determining a first power value based on inputs from the inlet temperature sensor and the flow sensor, the first power value being indicative of a power level required to heat the operating fluid to a setpoint temperature,second means for determining a second power value indicative of an actual power level being applied to the heating element, andthird means for controlling the switching device based on a difference between the first power value and the second power value.