Leak detection system for liquid processing device

摘要

A leak sensor system includes a leak sensor assembly 12 for use in liquid processing equipment such as a blood centrifuge, the leak sensor assembly being electrically connected with a leak sensor interface 14. The interface provides a source voltage Vs to the sensor assembly, receives a voltage output Vout by the assembly and correlates the comparison of the source and output voltages to a wet or dry condition within the equipment. Within the sensor assembly, R1 sets the reference voltage from Vs, and Rs is a distributed impedance, whose impedance value decreases dramatically in the presence of liquid. The effect of this impedance drop on the output voltage of the sensor indicates a wet or moist state, which may indicate leakage from the liquid processing. A terminal resistor Rt is in the circuit beyond the sensing resistor Rs to provide a warning indicator when the sensing resistor Rs is damaged or disconnected. The output voltage in the dry state is altered by the terminal impedance so that an output voltage approximately equal to the source voltage indicates the damage to Rs.