Portable liquid level detector

Abstract

A portable liquid level detector. The detector comprises a portable casing, a power supply unit disposed in the portable casing, a sensing device coupled to the power supply unit to sense a capacitance within a container and to output a enable signal when a difference in the capacitance is detected, a light emission device coupled to the sensing unit that illuminates after receiving the enable signal, and an alarm device coupled to the sensing unit that sounds after receiving the enable signal.

What is claimed is:  
     
         1 . A portable liquid level detector, comprising: 
 a portable casing;    a power supply unit disposed in the casing;    a sensor coupled to the power supply unit to sense whether a capacitance within a container is changed and to output a enable signal when the capacitance has changed; and    a signal device coupled to the sensor that outputs a signal after receiving the enable signal.    
     
     
         2 . A portable liquid level detector as claimed in  claim 1 , wherein the signal device is an alarm device.  
     
     
         3 . A portable liquid level detector as claimed in  claim 1 , wherein the signal device is a light emission device.  
     
     
         4 . A portable liquid level detector as claimed in  claim 3 , further comprising a resistor coupled to the light emission device to limit a current flowing through the light emission device.  
     
     
         5 . A portable liquid level detector as claimed in  claim 3 , wherein the light emission device is a light emission diode.  
     
     
         6 . A portable liquid level detector as claimed in  claim 2 , wherein the alarm device is a buzzer.  
     
     
         7 . A portable liquid level detector as claimed in  claim 1 , wherein the sensor is a capacitive proximity switch.  
     
     
         8 . A portable liquid level detector as claimed in  claim 1 , wherein the power supply unit is a battery set.  
     
     
         9 . A portable liquid level detector as claimed in  claim 1 , further comprising a switch coupled to the power supply unit to control the electrical conduction between the power supply unit and the sensor.  
     
     
         10 . A portable liquid level detector, comprise: 
 a portable casing;    a battery set deposed in the portable casing;    a capacitive proximity switch coupled to the battery set to sense whether a capacitance within a container is changed and to output a enable signal when the capacitance has changed;    a light emission diode coupled to the capacitive proximity switch that illuminates after receiving the enable signal;    a buzzer coupled to the capacitive proximity switch that sounds after receiving the enable signal;    a resistor coupled to the light emission diode to limit a current flowing through the light emission diode; and    a switch coupled to the battery set to control a electrical conduction between the battery set and the capacitive proximity switch.    
     
     
         11 . A method of detecting liquid level in a container, comprising: 
 moving a capacitive proximity switch into proximity of a container contains a liquid; and    moving the capacitive proximity switch upward and downward relative to the container until a difference in capacitance is detected.    
     
     
         12 . The method as claimed in  claim 11  wherein the container is nonmetallic, and the step of moving the capacitive proximity switch into proximity of the container brings the capacitive proximity switch into contact with the container.  
     
     
         13 . The method as claimed in  claim 11  wherein the container is metallic, and the step of moving the capacitive proximity switch into proximity of the container brings the capacitive proximity switch close to but not contact with the container.  
     
     
         14 . A method of detecting a clog jammed in a pipe, comprising: 
 moving a capacitive proximity switch into proximity of a pipe with a clog; and    moving the capacitive proximity switch upward and downward relative to the pipe until a difference in capacitance is detected.    
     
     
         15 . The method as claimed in  claim 14  wherein the container is nonmetallic, and the step of moving the capacitive proximity switch into proximity of the pipe brings the capacitive proximity switch into contact with the pipe.  
     
     
         16 . The method as claimed in  claim 14  wherein the container is nonmetallic, and the step of moving the capacitive proximity switch into proximity of the pipe brings the capacitive proximity switch close to but not in contact with the pipe.