| 摘要 |
A device is provided for detecting the ullage level and flow in a vessel (20) by detecting the pressure of a solid or liquid material (18) in proximity to a microwave detector (32). The device may be mounted to the side of the vessel (20) or suspended inside the vessel (20) so as to bring the microwave sensor into proximity with the surface of the contents of the vessel (20). A microwave bridge circuit (12) may be used to detect a change in either the amplitude or phase of a signal reflected by the material (18) within the vessel (20) compared to a reference signal tuned to either the presence or absence of the anticipated solid or liquid material (18). In one embodiment, the reflected material signal is compared to the signal from a sample chamber (30) containing the material (28) to be detected. The device can reliably detect the level of multiple interfaces for various materials having distinct electric or magnetic properties. |
