Constant Resistance Point Sensing for Propellant Gaging Systems 640485
A recently developed heated wire point liquid level detection system for use in cryogenic and other rocket propellants is described. Safety features include very low transducer element temperature in explosive gas mixtures, short circuit current limit below ignition thresholds, and remote checkout. Performance features include fast response, excellent interface resolution, and low power consumption. The controller maintains the level transducer element at nearly constant temperature in the varying thermal environment, and can differentiate liquid from gas by observation of the power dissipated. Application of the constant resistance control mode to both temperature control and direct measurement of fluid film heat transfer coefficients are considered.