초록 ▼

A liquid level monitoring system functions by applying an alternating voltage to a probe. When the liquid level in a reservoir touches the probe, a low impedance to ground is present, thereby permitting current to flow to ground. When the liquid level falls below the probe, a high impedance to groun

A liquid level monitoring system functions by applying an alternating voltage to a probe. When the liquid level in a reservoir touches the probe, a low impedance to ground is present, thereby permitting current to flow to ground. When the liquid level falls below the probe, a high impedance to ground is created and current flows to a detector. The detector switches on an alarm which flashes an appropriate warning.

대표청구항 ▼

A device for sensing the liquid level in a plurality of reservoirs each normally containing a quantity of a liquid to be dispensed, said device comprising: A. an electrical sensing probe suspended within each of said reservoirs; B. means defining an electrical circuit passing through each of said pr

A device for sensing the liquid level in a plurality of reservoirs each normally containing a quantity of a liquid to be dispensed, said device comprising: A. an electrical sensing probe suspended within each of said reservoirs; B. means defining an electrical circuit passing through each of said probes and through the liquid in the respective said reservoir to ground; C. means for applying a common alternating current to each of said probes to set up an alternating current flow in said circuit; and D. means sensing the impedance in each of said circuits and operative in response to a change in said impedance in any of said circuits caused by the liquid level dropping below the lower end of said probe, to activate a warning device to call attention to such low liquid level.