Method for eliminating output discontinuities in digital pressure transducers and digital pressure transducer employing same
AssigneeParoscientific, Inc.
InventorsJerome M. Paros, Theo P. Schaad
Life of this patent
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Abstract
Digital pressure transducers employing force-sensitive resonators are designed according to a method that eliminates spurious mode resonances. The dimensional and geometrical relationships of the force-producing pressure elements and structures are chosen such that spurious modes of oscillation are not excited by the resonant modes of the force-sensitive resonators.
Claims44
A transducer for providing an electrical signal having a frequency indicative of a differential pressure, comprising:
- a force-sensitive resonator controlling the frequency of the electrical signal, the resonator having at least one resonant element connected between a pair of mounts such that its resonant frequency is dependent on the elastic properties of the resonant element and the force applied to the resonant element through the mounts so that the frequency of the electrical signal varies as a function of the force applied to the resonator through the mounts;
- and
- a curved resilient pressure vessel having at least one closed end and a length of at least 4 cm, the pressure vessel having an interior and an exterior between which the differential pressure is applied, the pressure vessel being coupled to the mounts of the force-sensitive resonator and having a pressure-responsive configuration so that it generates forces through the mounts whose magnitude is a function of the differential pressure and the dimensions, composition, and geometry of the pressure vessel, the dimensions, composition, and geometry of the pressure vessel being such that any structural resonant frequencies of the pressure vessel are outside the ranges of frequencies coupled to the mounts by the force-sensitive resonator.
The transducer of claim I wherein the pressure vessel comprises a curved tube of noncircular cross-section and the mounts of the resonator are secured, respectively, to an area of the tube and a fixed base.
A transducer for providing an electrical signal having a frequency indicative of a differential pressure, comprising:
- a force-sensitive resonator controlling the frequency of the electrical signal, the resonator having at least one resonant element connected between a pair of mounts such that its resonant frequency is dependent on the elastic properties of the resonant element and the force applied to the resonant element through the mounts so that the frequency of the electrical signal varies as a function of the force applied to the resonator through the mounts;
- a curved resilient pressure vessel having at least one closed end, the pressure vessel having an interior and an exterior between which the differential pressure is applied, the pressure vessel being coupled to the mounts of the force-sensitive resonator and having a pressure-responsive configuration so that it generates forces through the mounts whose magnitude is a function of the differential pressure, the pressure vessel deforming within a bending plane responsive to the differential pressure;
- and
- an elongated pressure port coupled to the pressure vessel, the pressure port intersecting the pressure vessel along a longitudinal axis that is substantially out of the bending plane of the pressure vessel.
A transducer for providing an electrical signal having a frequency indicative of a differential pressure, comprising:
- a force-sensitive resonator controlling the frequency of the electrical signal, the resonator having at least one resonant element connected between a pair of mounts such that its resonant frequency is dependent on the elastic properties of the resonant element and the force applied to the resonant element through the mounts so that the frequency of the electrical signal varies as a function of the force applied to the resonator through the mounts;
- a curved resilient pressure vessel having at least one closed end, the pressure vessel having an interior and an exterior between which the differential pressure is applied, and having a pressure-responsive configuration so that it generates forces whose magnitude is a function of the differential pressure;
- and
- a pivotally mounted suspension arm that is connected to the pressure vessel and is mechanically isolated from the force-sensitive resonator by masses and springs which act as a low-pass mechanical filter.
A method of designing a pressure transducer, comprising:
- a curved pressure vessel that deforms responsive to a differential pressure;
- and
- a force-sensitive resonator that is coupled to the pressure vessel;
- and
- selecting the dimensions, geometry and composition of the pressure vessel and the frequency range of the resonator to avoid structural resonances in the pressure vessel at any resonant frequency of the resonator throughout the operating range of the pressure transducer.
Dependencies are inferred from the claim text.