초록 ▼

An improved capacitance bridge type liquid level control system for use in refrigeration applications is disclosed which provides improved apparatus for sealing the probe in its mounting and for insulating same against the condenser reservoir stand pipe in which it is mounted. Improved sealing betwe

An improved capacitance bridge type liquid level control system for use in refrigeration applications is disclosed which provides improved apparatus for sealing the probe in its mounting and for insulating same against the condenser reservoir stand pipe in which it is mounted. Improved sealing between the probe and probe body is accomplished through an annular PTFE seal which when compressed pushes inwardly to seal a tubular PTFE insulation against annular ridges in the side of the probe rod proper. The improved probe rod shape also maintains a proper stabilized axial alignment between the probe rod and the probe body. Improved circuitry for the capacitance bridge liquid level control system includes a built-in simulation circuit for testing the apparatus, improved voltage feedback damping for providing a stable circuitry utilizing digital display, light emitting diodes, improved anti-splashing circuitry for stabilizing digital display read out, and a reversed lower differential function setting for enabling the low level adjustment set point to be set more accurately heretofore known.

대표청구항 ▼

In a capacitance bridge liquid level control system for measuring the level of a liquid in a vessel, said level control system being of the type having a power supply, a signal generating oscillator, a capacitance bridge circuit for receiving a signal from said oscillator wherein a probe provides on

In a capacitance bridge liquid level control system for measuring the level of a liquid in a vessel, said level control system being of the type having a power supply, a signal generating oscillator, a capacitance bridge circuit for receiving a signal from said oscillator wherein a probe provides one plate of a capacitor thereof, and said bridge circuit being adapted for having a wall of a vessel providing an opposing plate of said capacitor thereof, wherein a change in the liquid level in said vessel causes a variance in the capacitance of said capacitor, a signal amplifying circuit for receiving and amplifying said signal from said capacitance bridge circuit, a level control circuit for receiving said amplified signal from said signal amplifying circuit and comparing same to a predetermined desired signal, and a display driver circuit for digitally displaying said amplified signal as a percentage of a full scale reading, an improvement for stabilizing the amplifier in said signal amplifying circuit wherein, a reference voltage is connected to said display driver circuit to display said reference voltage as a zero percent of full scale reading, diode means for regulating fluctuation in a positive input of said signal amplifier circuit about said reference voltage, and said diode means for regulating fluctuation in the positive input of said signal amplifier circuit balancing rapid current draw by said display driver circuit with the reference voltage varying but remaining constant relative to the zero reading output of said display driver circuit.