Apparatus and method for measuring fluid density

摘要

Apparatus for measuring fluid density in a fluid system has a sheath that surrounds a vibrating tube. The sheath and the tube form a cavity filled with a fixed amount of fluid. A pressure compensating element has a housing in which first and second pressure responsive surfaces are disposed. The first surface is in fluid communication with the cavity and the second surface is in fluid communication with the housing. A passage extends between the interior of the tube and the interior of the housing to exert the tube pressure on the second surface. The pressure on the second surface is transmitted to the cavity by the element to compensate for changes in the tube pressure. A method of compensating for line pressure changes in a densimeter that has a vibrating tube to sense density. A fixed amount of fluid fills a cavity formed around the tube. A first pressure responsive surface is in fluid communication with the cavity and a second fluid responsive surface is in fluid communication with the tube. The pressure on the second surface is transmitted to the cavity to compensate for changes in the tube pressure.