| 摘要 |
PURPOSE:To prevent an ultrasonic sensor from being influenced by heat and to relieve the influence due to a change in temperature, by a method wherein a false target is mounted to one end, positioned facing and opposite to a target, of a right-angled acoustic guide to be cooled. CONSTITUTION:An electric signal from a transmitting pulse generator 11 is converted into an ultrasonic pulse by an ultrasonic sensor 1 at one end of an acoustic guide 3, having a double-structure right-angled reflecting plate 4 to be cooled by a coolant and being free from the influence such as refraction, to reflect it by a false target at the other end of the guide 3 and a target facing oppositely to the other end. The reflecting ultrasonic waves, received by the sensor 1, are processed by an amplifier 12 and a signal processing part 13 to measure the level of the target 2. The constitution prevents the sensor from being suffered by a radiant heat from the high-temperature target 2 and being influenced by a high temperature, enables the acoustic guide, where the false target is mounted, to approach the high temperature target to measure a level, and relieves the influence by an atmosphere temperature, which results in performing a level measurement having a less absolute error. |
