US 4,644,796 A · Pressure measurement apparatus and method

Abstract

Fluid density measuring apparatus and method for directly measuring fluid density or indirectly measuring pressure. The apparatus includes a bellows and a generally rigid hollow housing having openings through which fluid may flow to the interior of the housing, and a vibratory single-ended tuning fork mounted in the housing. The apparatus also includes circuitry for causing the tines of the tuning fork to resonate, for example, 180 degrees out of phase in a transverse direction, with the frequency of the tines varying with variation in the density of the fluid surrounding the tines. Circuitry is also included for determining the frequency at which the tuning fork tines resonate. When the density of the fluid into which the housing is placed changes, the frequency of vibration of the tines of the tuning fork is caused to change to provide a measure of the pressure.

Claims9

Dependent claims

Gas density/pressure transducer apparatus comprising

a generally rigid hollow housing having an opening on one side,
an expandable and collapsible enclosure sealingly disposed over said opening so that the interiors of the housing and enclosure are in communication, and wherein the interior volume of the housing is less than the interior volume of the enclosure when the enclosure is expanded,
a gas contained in the housing and enclosure,
an elogate bar mounted in the housing and adapted to vibrate, said bar having a thickness T and width w, where T/w.gtoreq.0.1,
means for causing the bar to resonate at a frequency f, said frequency varying with variation in the density of the gas in the housing and enclosure and thus with variation of the exterior pressure on the housing and enclosure, and
means for determining the frequency f.

3 more elements

Dependencies are inferred from the claim text.

Pressure measurement apparatus and method

Life of this patent

Pressure measurement apparatus and method

Life of this patent

Abstract

Claims9