Patent ID: 7562570

Claim:
An ultrasonic monitor to measure the level of a fluid in a tank and comprising: an ultrasonic transducer adapted to generate an incident acoustic signal towards the surface of the fluid within the tank and to receive a return signal reflected off the surface of the fluid; a main central processing unit (CPU) being responsive to the incident and return signals generated by and reflected to the ultrasonic transducer for determining the elapsed time of flight therebetween and calculating the distance from the surface of the fluid to the ultrasonic transducer depending upon said elapsed time of flight; means to adjust the elapsed time of flight determined by the main CPU to compensate for errors introduced by the environment within the tank, whereby to maximize the accuracy of the distance calculated by the main CPU; an RF transceiver having an antenna and being interfaced with said main CPU for receiving data therefrom corresponding to the distance calculated by said main CPU, the antenna of said RF transceiver transmitting said distance data over a wireless communication path, said RF transceiver including a transceiver CPU responsive to a particular ID polling signal transmitted to the antenna of said RF transceiver when it is desirable to access the data corresponding to the distance calculated by said main CPU, said transceiver CPU supplying a wake-up signal to said main CPU for causing said ultrasonic transducer to generate said incident acoustic signal towards the surface of the fluid within the tank and the resulting data which is indicative of the distance calculated by the main CPU to be supplied to said transceiver CPU for transmission by said antenna; an infrared sensor interfaced with said main CPU; a gas-tight, explosion-proof casing enclosing at least some of each of said ultrasonic transducer, said main CPU, said RE transceiver, and said infrared sensor; and a transparent panel located in said gas-tight, explosion-proof casing, said infrared sensor positioned behind said transparent panel and responsive to a change in infrared energy applied through said transparent panel for supplying a corresponding wake-up signal to the main CPU, said main CPU being responsive to said wake-up signal for causing said ultrasonic transducer to generate said incident acoustic signal towards the surface of the fluid within the tank.