Electro-optic sensor for levelmeter providing output signal with frequency modulated by surface level
AssigneeTRN Business Trust
InventorHerman Díaz
Life of this patent
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Abstract
An opto-electric levelmeter having a sensor that provides an output signal whose frequency represents the surface level of liquid in a container. The sensor's circuitry includes an oscillation circuit that uses “optical feedback” to modulate the sensor output signal. The signal is delivered to a monitor that provides an output signal for the user. The monitor also permits adjustment for both high and low levels of a particular container. The monitor sends electrical energy to the sensor, and receives the sensor output signal on the same electrical link.
Claims20
An opto-electric levelmeter for measuring the level of liquid in a container, comprising:
- a sensor having at least a light emitting diode and a phototransistor, said sensor operable to provide a sensor output signal whose frequency is related to the distance of the sensor from the surface of the liquid;
- a monitor that receives the sensor output signal and that has at least linearizing circuitry for linearizing the sensor output signal, level detection circuitry for converting the output signal to a signal representing the level of liquid in the container, and adjustment circuitry for adjusting the level detection circuitry.
An opto-electric sensor that provides an output signal representing the level of liquid in a container, comprising:
- a light emitting diode that emits light toward the surface of the liquid;
- an optical transistor that detects light reflected from the surface of the liquid, thereby providing an optical link between the light emitting diode and the optical transistor;
- an oscillation circuit formed in part by the optical link between the light emitting diode and the optical transistor, wherein the oscillation circuit generates a sensor output signal whose frequency is representative of the level of liquid in the container;
- and
- a electrical port for delivering the sensor output signal to a remote monitor.
A method of sensing the level of liquid in a container, comprising the steps of:
- installing a sensor internal to the container;
- using the sensor to emit light to the surface of the liquid, to detect light reflected from the surface, and to generate a sensor output signal whose frequency represents the level of liquid in the container;
- transmitting the sensor output signal to a remote monitor;
- linearizing the sensor output signal;
- and
- converting the sensor output signal to a monitor output signal representing the level of liquid in the tank, such that the liquid level may be communicated to a user.
A method of sensing the level of liquid in a container, comprising the steps of:
- installing a sensor internal to the container;
- calibrating the sensor by placing, under the sensor, a surface whose reflective characteristics are the same as a known level of the liquid;
- using the sensor to emit light to the surface of the liquid, to detect light reflected from the surface, and to generate a sensor output signal whose frequency represents the level of liquid in the container;
- transmitting the sensor output signal to a remote monitor;
- and
- using the monitor to convert the sensor output signal to a monitor output signal representing the level of liquid in the tank, such that the liquid level may be communicated to a user.
Dependencies are inferred from the claim text.