| 摘要 |
<p>DENSITOMETER PROBE SHIELD AND WELL A vibration densitometer having a probe with a thin vibrating vane, and a feedback loop for vibration of the vane at a resonance varying with the density of a fluid in which the vane is immersed. With conventional linearization, the densitometer output can indicate fluid density, operate a process control system or otherwise. A probe shield and well have solved a perplexing problem. In the past, the densitometer would take a calibration shift if the probe were placed in different gases or in the hollow interiors or pipelinesof different sizes or geometries or the probe was placed in the same container or pipeline with different orientations. The shield and well have solved the calibration shift problem in all of these cases. It is also an advantage of the shield and well that they improve densitometer accuracy over broad density and flow rate ranges and decrease temperature instability and long start-up times. Perplexing phase shifts caused inaccuracies. The well and shield have also solved another serious problem where oscillation failed. In other words, before the shield was used, a densitometer "lost lock." Unusual restricted shield perforations and ports improve operation and accuracy by limiting pitot(ram pressure), turbulence and other undesirable flow effects when the densitometer probe and shield is immersed in either compressible or "incompressible" fluids, e.g. gases and liquids, respectively. The shield enables operation under conditions of high amplitude flow noise where operation therein is not possible without the shield.</p> |
