Multi-measurement vortex flow meter
First Claim
1. A method of specifying a transmitter, the transmitter for regulating an amplitude of a supplied current to encode a parameter, the method comprising providing a set of data to a customer, wherein the set of data represents a maximum allowable load at one or more supply voltage levels, and the set of data has a first segment operable only for a lower range of currents below a transition current and has a second segment operable only for a higher range of currents above the transition current.
5 Assignments
0 Petitions
Accused Products
Abstract
Two-wire transmitters are described in which the required voltage that a control room must supply to the transmitter is lower at high current than at low current, thus freeing up more voltage for other uses, and in which a constant set of operating voltages may be maintained. A corrected pressure in a vortex flow meter may be determined that reflects the mass flow rate. Thus, the mass flow rate may be determined based on the corrected pressure reading and a measured volumetric flow rate. Density may be determined from pressure and temperature using a table containing error values based on a standard density determination and a relatively simple approximation. During operation of a flow meter, the stored error values may be linearly interpolated and the approximation may be computed to determine the density from the stored error value.
117 Citations
63 Claims
- 1. A method of specifying a transmitter, the transmitter for regulating an amplitude of a supplied current to encode a parameter, the method comprising providing a set of data to a customer, wherein the set of data represents a maximum allowable load at one or more supply voltage levels, and the set of data has a first segment operable only for a lower range of currents below a transition current and has a second segment operable only for a higher range of currents above the transition current.
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4. A method of controlling a current signal, the method comprising:
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receiving a current with a variable amplitude over a line, the amplitude being regulated;
multiplying the regulated amplitude by a first non-unitary factor when the regulated amplitude is below a first level;
multiplying the regulated amplitude by a second non-unitary factor when the regulated amplitude is above a second level;
maintaining a constant set of operating voltages whether the regulated amplitude is multiplied by the first non-unitary factor or the second non-unitary factor; and
providing the multiplied amplitude and the constant set of operating voltages to circuitry. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11, 12)
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13. A transmitter comprising:
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a switching circuit configured to couple a regulated current to either a first output or a second output based on an amplitude of the regulated current;
a first non-unitary current multiplier having an input and an output, with the input of the first non-unitary multiplier being coupled to the first output of the switching circuit, the first non-unitary multiplier operable in a forward direction as a current multiplier and in a backward direction as a current divider; and
a second non-unitary multiplier having an input and an output, with the input of the second non-unitary multiplier coupled to both the second output of the switching circuit and the output of the first non-unitary multiplier. - View Dependent Claims (14, 15, 16, 17)
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18. A transmitter comprising:
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switching means, having a first output and a second output, for coupling a regulated current to either the first output or the second output based on an amplitude of the regulated current;
first means for multiplying current by a non-unitary number, the first means having an input and an output, with the input of the first means being coupled to the first output of the switching means, the first means being operable in a forward direction as a current multiplier and in a backward direction as a current divider; and
second means for multiplying current by a non-unitary number, the second means having an input and an output, with the input of the second means being coupled to both the second output of the switching means and the output of the first means. - View Dependent Claims (19)
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20. A method of determining a pressure, the method comprising:
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measuring a pressure of a fluid flowing through a system;
measuring a temperature of the flowing fluid;
determining a velocity of the flowing fluid; and
determining a corrected pressure for the flowing fluid based on the pressure, the temperature, and the velocity, the corrected pressure corresponding to a density reflective of the velocity and a mass flow rate. - View Dependent Claims (21, 22, 23, 24, 25, 26)
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27. A device comprising a storage medium having instructions stored thereon that when executed result in at least the following:
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measuring a pressure of a fluid flowing through a system;
measuring a temperature of the flowing fluid;
determining a velocity of the flowing fluid; and
determining a corrected pressure for the flowing fluid based on the pressure, the temperature, and the velocity, the corrected pressure corresponding to a density reflective of the velocity and a mass flow rate. - View Dependent Claims (28, 29)
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30. A method of calibrating a device, the method comprising:
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measuring a pressure of a fluid flowing in a system;
measuring a temperature of the flowing fluid;
determining a density of the flowing fluid based on the pressure and the temperature;
determining a velocity of the flowing fluid;
determining a volumetric flow rate of the flowing fluid;
determining a corrected pressure using a mass flow rate, the determined volumetric flow rate, and the measured temperature, wherein the corrected pressure corresponds to a corrected density reflective of the determined velocity and the mass flow rate; and
determining a calibration constant kdiff according to the following equation;
- View Dependent Claims (31, 32)
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33. A device comprising a storage medium having instructions stored thereon that when executed result in at least the following:
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measuring a pressure of a fluid flowing in a system;
measuring a temperature of the flowing fluid;
determining a density of the flowing fluid based on the pressure and the temperature;
determining a velocity of the flowing fluid;
determining a volumetric flow rate of the flowing fluid;
determining a corrected pressure using a mass flow rate, the determined volumetric flow rate, and the measured temperature, wherein the corrected pressure corresponds to a corrected density reflective of the determined velocity and the mass flow rate; and
determining a calibration constant kdiff according to the following equation;
- View Dependent Claims (34)
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35. A method of calibrating a device, the method comprising:
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measuring a pressure of a fluid flowing in a system;
measuring a temperature of the flowing fluid;
determining a density of the flowing fluid based on the pressure and the temperature;
determining a velocity of the flowing fluid;
determining a volumetric flow rate of the flowing fluid; and
determining a calibration constant, using a known speed of sound in the flowing fluid and a mass flow rate, according to the following equation;
- View Dependent Claims (36, 37)
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38. A device comprising a storage medium having instructions stored thereon that when executed result in at least the following:
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measuring a pressure of a fluid flowing in a system;
measuring a temperature of the flowing fluid;
determining a density of the flowing fluid based on the pressure and the temperature;
determining a velocity of the flowing fluid;
determining a volumetric flow rate of the flowing fluid; and
determining a calibration constant, using a known speed of sound in the flowing fluid and a mass flow rate, according to the following equation;
- View Dependent Claims (39)
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40. A method of computing density, the method comprising:
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accessing a pressure input and a temperature input;
determining a density error for the pressure input and temperature input based on one or more stored density errors, wherein the one or more stored density errors each reflect error between a density approximation and a standard density value for a different pressure input and temperature input;
determining a density approximation for the pressure input and temperature input; and
determining a density value for the pressure input and temperature input based on the density error for the pressure input and temperature input and the density approximation for the pressure input and temperature input. - View Dependent Claims (41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51)
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52. A device comprising a storage medium having instructions stored thereon that when executed result in at least the following:
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accessing a pressure input and a temperature input;
determining a density error for the pressure input and temperature input pair based on one or more stored density errors, wherein the one or more stored density errors each reflect error between a density approximation and a standard density value for a different pressure input and temperature input;
determining a density approximation for the pressure input and temperature input; and
determining a density value for the pressure input and temperature input based on the density error for the pressure input and temperature input and the density approximation for the pressure input and temperature input. - View Dependent Claims (53)
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54. A device comprising a storage medium having stored thereon density errors computed using at least the following operations:
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determine a standard density value for each of multiple pressure and temperature input pairs;
determine a density approximation for each of the multiple pressure and temperature input pairs; and
determine a density error, based on the standard density value and the density approximation, for each of the multiple pressure and temperature input pairs. - View Dependent Claims (55, 56, 57, 58, 59, 60, 61, 62, 63)
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Specification