| 摘要 |
PURPOSE:To detect the presence of or changes in various fluids, by checking variations in the electric current to electrically energize a non-linear resistance element having a positive resistance temperature coefficient. CONSTITUTION:A non-linear resistance element 1 is fixed at a fixed height above the bottom of a tank inner wall. When a tank is empty, air surrounds the element 1 and the element 1 self-heated with a power source 2 takes balance maintaining a specified temperature being balanced with a heat radiation through a heat resistance to the air, which causes a balanced current to flow to a resistance 3. Thereafter, when a fluid is poured into the tank to wrap the element 1, the heat resistance of the element 1 to the fluid changes so sharply that a rapid heating current is fed to the element 1 from the power source 2 to restore the balance. The heating balanced current of the element 1 at this point will increase according to the increment of heat radiation, the voltage inputted into a detection circuit 4 through the resistance 3 changes corresponding to changes in the current at an equilibrium. The circuit 4 checks the changes to light an alarm lamp with of a relay of a driving circuit 5 and a load 6 thereby enabling the detection of the fluid.
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