JP2003065816A - Electromagnetic flowmeter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromagnetic flowmeter for providing mass flow measurement capable of conducting temperature correction for density to enhance measuring precision, based on a measured temperature value of which the temperature noise is removed. SOLUTION: In this electromagnetic flowmeter provided with earthing electrodes, the first earthing electrode provided in an upstream, the second earthing electrode provided in a downstream of the first earthing electrode, the first and second sensors provided respectively in the first and second earthing electrodes, a temperature noise removing circuit for computing detection signals of the first and second sensors to remove a temperature noise, a density temperature correction-computing circuit for computing a temperature-corrected value of the density based on the measured temperature value of which the temperature noise is removed, and a mass-flow calculating circuit for computing a mass-flow rate value, based on the temperature-corrected value of the density and a measured flow rate value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention makes it possible to correct the temperature of the density by the temperature measurement value from which the temperature noise value is removed
The present invention relates to an electromagnetic flow meter that can obtain a mass flow rate measurement with improved measurement accuracy.

[0002]

2. Description of the Related Art FIG. 8 is an explanatory view of a principle configuration of a conventional example which is generally used conventionally. As shown in FIG. 8, when a uniform magnetic field having a magnetic flux density B is applied to a pipe having an inner diameter D, when a conductive liquid having an average flow velocity v flows, the magnetic field and the flow E are respectively perpendicular to each other. = D · v · B electromotive force E is generated.

Since the volumetric flow rate Q is expressed as Q = π / 4 · D ² · v = π / 4 · D / BE · E, the flow rate Q is proportional to the electromotive force E if the magnetic flux density B is constant. . The conventional electromagnetic flowmeter detects the electromotive force E and measures the volumetric flow rate Q.

[0004]

However, in such a device, only the volume flow rate Q can be measured.

An object of the present invention is to solve the above-mentioned problems and to obtain a mass flow rate measurement in which the temperature measurement value from which the temperature noise value is removed can correct the density temperature and the measurement accuracy is improved. It is to provide a flow meter.

[0006]

In order to achieve such an object, according to the present invention, in the electromagnetic flowmeter according to claim 1, the electromagnetic flowmeter provided with an earth electrode is provided on the upstream side. One ground electrode, a second ground electrode provided on the downstream side of the first ground electrode, and first and second ground electrodes provided on the first and second ground electrodes, respectively.
Temperature sensor, a temperature noise removal circuit that operates the detection signals of the first and second temperature sensors to remove temperature noise, and a temperature correction value of density is calculated from the temperature measurement value from which the temperature noise is removed. And a mass flow rate calculation circuit for calculating a mass flow rate value from the temperature correction value of the density and the measured flow rate value.

According to a second aspect of the present invention, in the electromagnetic flowmeter according to the first aspect, the first and second temperature sensors are provided on the earth rings provided on the upper and lower sides, respectively. It is characterized in that it is provided on each of the ground electrodes.

According to a third aspect of the present invention, in the electromagnetic flowmeter according to the first or second aspect, at least four temperature sensors are arranged so as to face each other at right angles to the flow direction of the fluid to be measured and to form a pair. It is characterized in that it is provided on each of the ground electrodes.

[0009]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail below with reference to the drawings. FIG. 1 is an explanatory view of the main configuration of an embodiment of the present invention
FIG. 2 is an explanatory view of the main configuration of FIG. In the figure, FIG.
The configurations of the same symbols as and represent the same functions. Only the parts different from FIG. 8 will be described below.

In the figure, 1 is a measuring tube, and 2 is a lining body provided on the measuring tube 1. In this case, a fluororesin lining is used. 3 is a first earth electrode provided on the upstream side.

Reference numeral 4 is a second ground electrode provided downstream of the first ground electrode 3. Reference numerals 5 and 6 are first and second temperature sensors provided on the first and second ground electrodes 3 and 4, respectively.

As shown in FIG. 3, reference numeral 7 is a temperature noise removing circuit for calculating the detection signals of the first and second temperature sensors 5 and 6 to remove temperature noise. Temperature noise is, for example,
By averaging the signals obtained from the first and second temperature sensors 5 and 6, the noise component can be reduced and the S / N ratio can be reduced.
It is possible to obtain a signal with a good ratio.

When the number of temperature sensors becomes four,
By increasing the number of inputs and averaging, noise can be further reduced and a signal with a good S / N ratio can be obtained. Reference numeral 8 denotes a density temperature correction calculation circuit that calculates a temperature correction value of the density based on the temperature measurement value from which the temperature noise is removed.

Reference numeral 9 is a mass flow rate calculation circuit for calculating a mass flow rate value from the temperature correction value of the density and the measured flow rate value Q.

In the above configuration, the temperature noise measured by the first and second temperature sensors 5 and 6 is removed by the temperature noise removing circuit 7. In the density temperature correction calculation circuit 8, the temperature correction value of the density ρ is calculated based on the temperature measurement value from which the temperature noise is removed.

[0016] In the mass flow rate computation circuit 9, Q _{m =} mass than ρQ flow Q _m and a temperature correction value and the measured flow rate value Q of the density ρ is calculated.

As a result, the first earth electrode 3 provided on the upstream side, the second earth electrode 4 provided on the downstream side of the first earth electrode 3, and the first and second earth electrodes Temperature noise removing circuit 7 that removes temperature noise by calculating detection signals of the first and second temperature sensors 5 and 6 respectively provided in 3 and 4 and the first and second temperature sensors 5 and 6.
And a density temperature correction calculation circuit 8 for calculating a temperature correction value for the density based on the temperature measurement value from which the temperature noise has been removed, and a mass flow rate for calculating a mass flow rate value from the temperature correction value for the density and the measured flow rate value Q. Arithmetic circuit 9 is provided.

Therefore, since the temperature of the measurement fluid FL from which the temperature noise is removed can be measured, the temperature of the density ρ can be corrected from the value, and an electromagnetic flow meter capable of mass flow measurement with improved measurement accuracy can be obtained. .

FIG. 4 is an explanatory view of a main part configuration of another embodiment of the present invention, and FIG. 5 is a sectional view taken along line AA of FIG. In this embodiment, 11a, 11b, 12a, 12b are a pair of ground electrodes that are arranged to face each other at right angles to the flow direction of the measurement fluid FL. In this case, the ground electrode 11a
And the ground electrode 11b are arranged to face each other at right angles to the flow direction of the measurement fluid FL to form a pair.

The ground electrode 12a and the ground electrode 12b are arranged so as to face each other at right angles to the flow direction of the measurement fluid FL and form a pair. 13a, 13b, 14a, 14b are
These are temperature sensors provided on the ground electrodes 11a, 11b, 12a, 12b, respectively.

As a result, the temperature sensors 13a, 13b, 1
4a and 14b are arranged so as to face each other at right angles to the flow of the measurement fluid FL and form a pair with the ground electrodes 11a and 11b.
Since they are provided in 2a and 12b, respectively, the facing arrangement improves the temperature measurement accuracy, and an electromagnetic flowmeter capable of mass flow measurement with improved measurement accuracy can be obtained.

FIG. 6 is an explanatory view of the main part configuration of another embodiment of the present invention, and FIG. 7 is an explanatory view of the main part configuration of FIG. In this embodiment, the first and second temperature sensors 21 and 22 are provided on the first and second earth rings 23 and 24 provided on the upper and lower sides, respectively. 26 are provided respectively.

Reference numeral 31 is a coil provided on the measuring tube 1, and 32 is a lining body provided on the first and second earth rings 23 and 24.

As a result, (1) the first and second temperature sensors 21 and 22 are provided on the earth rings 23 and 24 provided on the upper and lower sides, respectively.
Since the earth rings 23 and 24 are respectively provided on the second earth electrodes 25 and 26, the earth rings 23 and 24 can be easily assembled and removed, and thus the electromagnetic flow rate with which the maintainability of the first and second temperature sensors 21 and 22 is improved. The total is obtained.

(2) Since it is extremely easy to replace the earth rings 23 and 24, the conventional electromagnetic flowmeter is
The function can be easily improved to the electromagnetic flow meter to which the function capable of measuring the mass flow rate with improved measurement accuracy is added.

The above description merely shows specific preferred embodiments for the purpose of explaining and exemplifying the present invention. Therefore, the present invention is not limited to the above embodiments, and includes many modifications and variations without departing from the essence thereof.

[0027]

As described above, according to the first aspect of the present invention.
According to the above, there are the following effects. A temperature noise removal circuit that computes detection signals of the first and second temperature sensors to remove temperature noise, and a density temperature correction computation circuit that computes a temperature correction value of density from the temperature measurement value from which this temperature noise has been removed. Since the mass flow rate calculation circuit that calculates the mass flow rate value from the temperature correction value of the density and the measured flow rate value is provided, an electromagnetic flow meter capable of measuring the mass flow rate with improved measurement accuracy can be obtained.

According to claim 2 of the present invention, there are the following effects. (1) Since the first and second temperature sensors are provided on the first and second earth electrodes provided on the earth rings provided on the upper and downstream sides, the earth ring is easy to assemble and remove. Therefore, it is possible to obtain the electromagnetic flowmeter in which the maintainability of the first and second temperature sensors is improved.

(2) Since it is extremely easy to replace the earth ring, the conventional electromagnetic flowmeter can be easily upgraded to an electromagnetic flowmeter with a function capable of measuring mass flow rate with improved measurement accuracy. I can.

According to claim 3 of the present invention, there are the following effects. Since at least four temperature sensors are arranged to face each other in a pair orthogonal to the flow of the fluid to be measured and provided to the pair of ground electrodes, the facing arrangement further improves the accuracy of temperature measurement and further improves the measurement accuracy. An electromagnetic flowmeter capable of improved mass flow measurement is obtained.

Therefore, according to the present invention, it is possible to realize an electromagnetic flowmeter which can perform temperature correction of density and obtain mass flow rate measurement with improved measurement accuracy by the temperature measurement value from which the temperature noise value is removed. I can.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a main part configuration of an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a main configuration of FIG.

FIG. 3 is a block diagram of an electric circuit of a main part of FIG.

FIG. 4 is an explanatory diagram of a main part configuration of another embodiment of the present invention.

5 is a cross-sectional view taken along the line AA of FIG.

FIG. 6 is an explanatory diagram of a main part configuration of another embodiment of the present invention.

FIG. 7 is an explanatory diagram of a main part configuration of FIG. 6;

FIG. 8 is an explanatory diagram of a main part configuration of a conventional example that is generally used in the past.

[Explanation of symbols]

1 measuring tube 2 lining body 3 First earth electrode 4 Second earth electrode 5 First temperature sensor 6 Second temperature sensor 7 Temperature noise removal circuit 8 Density temperature correction calculation circuit 9 Mass flow rate calculation circuit 11a Earth electrode 11b Earth electrode 12a Earth electrode 12b Earth electrode 13a Temperature sensor 13b Temperature sensor 14a Temperature sensor 14b Temperature sensor 21 First Temperature Sensor 22 Second temperature sensor 23 First Earth Ring 24 Second Earth Ring 25 First ground electrode 26 Second ground electrode 31 coils 32 lining body FL measuring fluid

Claims (3)

[Claims] 1. An electromagnetic flowmeter having a ground electrode, wherein a first ground electrode provided on the upstream side, a second ground electrode provided on the downstream side of the first ground electrode, First and second temperature sensors provided on the first and second ground electrodes, respectively, and a temperature noise removing circuit for calculating detection signals of the first and second temperature sensors to remove temperature noise, A density temperature correction calculation circuit that calculates a temperature correction value of the density based on the temperature measurement value from which temperature noise is removed, and a mass flow rate calculation circuit that calculates a mass flow rate value from the temperature correction value of the density and the measured flow rate value. An electromagnetic flowmeter characterized by the above. 2. The first and second temperature sensors are respectively provided on first and second earth electrodes provided on earth rings provided on the upper and lower sides, respectively.
The electromagnetic flowmeter described. 3. The at least four temperature sensors are respectively arranged on a pair of earth electrodes, which are arranged to face each other at right angles to the flow direction of the measurement fluid.
Alternatively, the electromagnetic flowmeter according to claim 2.