| 摘要 |
PROBLEM TO BE SOLVED: To provide a level gage which can measure a level in a noncontact manner. SOLUTION: When a laser light source 3a emits a laser beam, a condenser lens 3b condenses the laser beam, an optical filter 3c expands the laser beam, and a bubble surface B1 is irradiated with the laser beam. When reflected light reflected by the buble surface B1 is condensed on a light receiving element 3e by a condenser lens 3d, the light receiving element 3e outputs an electric signal according to the intensity of the reflected light. An arithmetic circuit 3g computes the phase difference between the laser beam and the reflected light so as to detect the level of the bubble surface B1. Since the level is measured in a noncontat manner with reference to the bubble surface B1, the level can be measured stably. Since the level gage does not require a maintenance operation such as a disassembling operation, a cleaning operation or the like, its rate of operation can be enhanced. |
