Isolator for pressure transmitter
First Claim
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1. A pressure transmitter, comprising:
- a body having a surface including a rim around a shaped concavity coupled to a port in the transmitter via a passageway in the body, the concavity having a central region surface portion;
a diaphragm isolating the concavity from received process fluid, the diaphragm having an outer region sealed to the rim surrounding a corrugated diaphragm region which surrounds an uncorrugated central diaphragm region, overlying the central region of the concavity, the diaphragm having an undeflected position at a first temperature and a deflected position where it is deflected toward the concavity at a second lower temperature;
isolator fluid in the concavity and passageway coupling pressure to the port; and
a pressure sensor receiving pressure from the port and generating a pressure output;
the central region of the diaphragm having a substantially flat shape at the undeflected position and having a depressed shape at the deflected position, the concavity central region surface portion having a concave shape corresponding to the depressed shape of the diaphragm to reduce output error due to temperature variations.
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Abstract
In a pressure transmitter, a central region of an isolator diaphragm with a substantially flat shape at an undeflected position near room temperature has a depressed shape at a deflected position at a colder temperature. The isolator diaphragm is over a shaped concavity in a transmitter body with a concave shape which corresponds to the depressed diaphragm shape to reduce output error.
45 Citations
13 Claims
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1. A pressure transmitter, comprising:
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a body having a surface including a rim around a shaped concavity coupled to a port in the transmitter via a passageway in the body, the concavity having a central region surface portion; a diaphragm isolating the concavity from received process fluid, the diaphragm having an outer region sealed to the rim surrounding a corrugated diaphragm region which surrounds an uncorrugated central diaphragm region, overlying the central region of the concavity, the diaphragm having an undeflected position at a first temperature and a deflected position where it is deflected toward the concavity at a second lower temperature; isolator fluid in the concavity and passageway coupling pressure to the port; and a pressure sensor receiving pressure from the port and generating a pressure output; the central region of the diaphragm having a substantially flat shape at the undeflected position and having a depressed shape at the deflected position, the concavity central region surface portion having a concave shape corresponding to the depressed shape of the diaphragm to reduce output error due to temperature variations. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A pressure transmitter, comprising:
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a body having a surface including a rim around a shaped concavity coupled to a port in the transmitter via a passageway in the body, the concavity being defined by a surface portion that has a central region; a diaphragm isolating the concavity from received process fluid, the diaphragm having an outer region sealed to the rim surrounding a corrugated diaphragm region which surrounds a smooth uncorrugated central diaphragm region, the diaphragm having an undeflected position at a first temperature and a deflected position where it is deflected toward and is closely spaced from the concavity surface portion at the central region at a second lower temperature; isolator fluid in the concavity and passageway coupling pressure to the port; and a pressure sensor receiving pressure from the port and generating a pressure output; the central region of the diaphragm having a substantially flat shape at the undeflected position and having a preformed, concave depressed shape at the deflected position, the surface portion at the central region of the concavity having a substantially smooth, uncorrugated concave shape corresponding to the preformed depressed shape of the diaphragm to reduce output error by reducing the volume of fluid between the diaphragm and the surface of the concavity to reduce effects of temperature variations.
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Specification