초록 ▼

An apparatus for measuring the level of material in a container includes a timer which responds to the change in the capacitance of a probe as the level of the material varies with respect thereto. An oscillator periodically strobes said timer, which thereafter remains on for a length of time determ

An apparatus for measuring the level of material in a container includes a timer which responds to the change in the capacitance of a probe as the level of the material varies with respect thereto. An oscillator periodically strobes said timer, which thereafter remains on for a length of time determined by said probe capacitance. A meter indicates this timer on-time, thereby providing a measure of the detected probe capaictance, and thus the level of material. The on-time of said oscillator is also variable, the output thereof being coupled to said meter to hold said meter off for a time equal to the time said timer is caused to be on due to the residual capacitance of the probe existing even when no material is present. One or more flag timers are also provided, including the ability to adjust the on-time of each said flag timer to provide an indication of a critical level or of a level above or below such level.

대표청구항 ▼

An apparatus for measuring the level of material in a container comprising: probe means; level indicator means; first timer means operatively connected to said probe means such that the on-time of said timer, when it is strobed, is a function of the capacitance of said probe means; means for couplin

An apparatus for measuring the level of material in a container comprising: probe means; level indicator means; first timer means operatively connected to said probe means such that the on-time of said timer, when it is strobed, is a function of the capacitance of said probe means; means for coupling the output of said first timer means to said level indicator means; oscillator means for periodically strobing said first timer means, said oscillator means including means for presetting the on-time of said oscillator means such that said oscillator means remains on for a length of time equal to the time said first timer means remains on due to the residual capacitance in said probe means; means for adjusting said presetting means; and means responsive to said oscillator means for holding off said indicator means during the on-time of said oscillator means.