| 摘要 |
PURPOSE:To know the remaining amount of a reservoired liquid even at a distance by providing the cap of a tank with a remaining amount decision means which decides the remaining amount of the reservoired liquid and sending its decision result to the outside as a radio signal. CONSTITUTION:A wave transmission part 20 in a cap 18 which opens and closes the liquid feed opening 16 of the tank 2 sends a wave S toward the surface of the liquid 14 in the tank 2. Then a reflected wave of the sent wave S which is obtained from the surface of the liquid 14 is received by a wave reception part 22. The remaining amount decision part 24 measures the time from the transmission of the sent wave S from the transmission part 20 to the reception of the received wave R to decide the remaining amount of the liquid 14. A transmitter 26 sends the decision result to the outside as the radio signal consisting of a signal transmission medium such as a radio wave and light. A transmitting antenna 29 for the use of the radio wave as the signal transmission medium is installed outside the cap 18. |
