JP2007071695A - Electromagnetic flowmeter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic flowmeter capable of measuring a flow rate accurately. <P>SOLUTION: In this electromagnetic flowmeter 30 of the present invention, a bar code reader 47 provided in a clamp part 40 reads an inside diameter dimension D of a measuring flow passage 26A, from a bar code 52 printed in a new disposable housing 50, when replacing the disposable housing 50 attached to the clamp part 40, and an MPU 38 reflects the inside diameter dimension D onto a flow rate computing coefficient C1. The MPU 38 computes the flow rate of a fluid by multiplying an induced voltage E detected by detecting electrodes 33, 33 with the flow rate computing coefficient C1. That is, the new flow rate computing coefficient C1 is determined in response to the inside diameter dimension D of the measuring flow passage 26A provided in the new disposable housing 50, in the every replacement of the disposable housing 50 into the new one, and the accurate flow rate is measured all the time because the flow rate of the fluid is computed using the flow rate computing coefficient C1. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  According to the present invention, a disposable disposable housing having a measurement flow path is detachably mounted on a base housing to apply a magnetic field to the liquid in the measurement flow path, and the flow rate of the liquid is determined based on the induced voltage generated at this time. The present invention relates to an electromagnetic flow meter that measures the above.

Conventionally, in an electromagnetic flow meter having this type of disposable housing, the configuration of the arithmetic processing unit that calculates the flow rate from the induced voltage has the same configuration as a general electromagnetic flow meter (having no disposable function). (For example, refer to Patent Document 1). In the general electromagnetic flow meter, the flow rate calculation coefficient C3 in the following known formulas (a) and (b) is stored in advance, and the detected induced voltage E is multiplied by the flow rate calculation coefficient C3 to obtain a liquid flow rate. I was looking for Q.
Q = C3 · E (a)
C3 = (π · D) / (4k · B) (b)
Note that D is the inner diameter when the measurement channel is circular in cross section, B is the magnetic flux density applied to the measurement channel, and k is a predetermined constant (for example, see Non-Patent Document 1).
JP-A-4-324321 Matsuyama Hiroshi, “Practical flow rate measurement”, 1st edition, Energy Conservation Center, June 15, 1999, p. 42

  However, in the above-described conventional electromagnetic flowmeter, when the inner diameter of the measurement flow path varies between disposable housings to be replaced, the measurement results also vary, making it difficult to accurately measure the flow rate.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an electromagnetic flow meter capable of accurately measuring a flow rate.

  An electromagnetic flow meter according to the invention of claim 1 made to achieve the above object includes a disposable disposable housing having a measurement channel through which a liquid passes, and a base housing to which the disposable housing is detachably mounted. An electromagnetic coil that is provided in the base housing and applies a magnetic field to the liquid in the measurement channel; and an induction coil that is provided in the disposable housing and detects an induced voltage generated by the liquid passing through the measurement channel. In an electromagnetic flowmeter comprising a detection electrode and an arithmetic processing unit that calculates the flow rate of the liquid by multiplying the induced voltage detected by the detection electrode by a flow rate calculation coefficient, the disposable housing has an inner diameter dimension of the measurement channel. An information carrier with disposable specific data that can change according to variations and / or specification changes is provided, and the base housing has a disposable housing An information acquisition means capable of acquiring the disposable specific data from the information carrier in a worn state is provided, and the arithmetic processing unit reflects the disposable specific data acquired from the information carrier through the information acquisition means in the flow rate calculation coefficient, and the flow rate is calculated. It has a characteristic in the place to calculate.

According to a second aspect of the present invention, in the electromagnetic flowmeter according to the first aspect, the information carrier has the inner diameter dimension of the measurement channel as disposable inherent data, and the arithmetic processing section sets the inner diameter dimension to D, and the magnetic flux of the magnetic field. When the density is B, the predetermined constant is k, and the flow rate calculation coefficient is C1, the following equation:
C1 = (π · D) / (4k · B)
The flow rate calculation coefficient C1 determined by the above is reflected in the inner diameter dimension D as disposable inherent data, and the flow rate is calculated by multiplying the flow rate calculation coefficient C1 by the induced voltage.

According to a third aspect of the present invention, in the electromagnetic flowmeter according to the first aspect, the inner diameter dimension of the measurement channel is D, the magnetic flux density of the magnetic field is B, the predetermined constant is k, and the flow rate calculation coefficient is C1. In the case, the information carrier has the following formula:
C1 = (π · D) / (4k · B)
The flow rate calculation coefficient C1 determined by the above-mentioned is provided as disposable characteristic data, and the calculation processing unit is characterized in that the flow rate is calculated by multiplying the induced voltage by the flow rate calculation coefficient C1 acquired as the disposable characteristic data.

  According to a fourth aspect of the present invention, in the electromagnetic flowmeter according to any one of the first to third aspects, the arithmetic processing unit stores base unique data that can change according to variations between base housings and / or specification changes. The base data storage unit is provided, and the flow rate is calculated by reflecting the base specific data in the flow rate calculation coefficient.

  According to a fifth aspect of the present invention, in the electromagnetic flowmeter according to the fourth aspect of the present invention, the base data storage unit uses a base housing that is normally used and a reference base housing, and both are measured under the same conditions. The types of actual measurement values for calibration or the ratio of these two types of actual measurement values for calibration are stored as base specific data, and the arithmetic processing unit calculates the ratio or base obtained from the two types of actual measurement values for calibration as base specific data. The characteristic is that the flow rate calculation coefficient is corrected by multiplying the flow rate calculation coefficient by the ratio of the two kinds of calibration actual measurement values as the unique data.

  A sixth aspect of the present invention is the electromagnetic flowmeter according to any one of the first to fifth aspects, wherein the flow rate of the liquid filling the measurement flow path is zero, and the detection electrode is used for the zero flow rate liquid. The zero-point data update storage means that stores the induced voltage actually detected as zero-point data and the latest zero-point data stored in the zero-point data update storage means are detected when the liquid flows in the measurement channel. It is characterized in that it includes a zero point correction unit that performs zero point correction by subtracting from the induced voltage detected by the electrode.

  According to a seventh aspect of the present invention, in the electromagnetic flowmeter according to any one of the first to sixth aspects, the information carrier is a bar code, the information acquisition means is a bar code reader, and the bar code and the bar code reader are a disposable housing. It has the characteristics in the place arrange | positioned in the part which mutually opposes in the state mounted to the base housing. Here, the “barcode” in the present invention includes a one-dimensional barcode and a two-dimensional barcode.

  The invention of claim 8 is characterized in that, in the electromagnetic flowmeter according to claims 1 to 6, the information carrier is an RF tag, and the information acquisition means is a tag reader.

  The “RF tag” in the present invention refers to the one defined in “JIS X 0500 data carrier term”. In other words, it is “an information medium that has a built-in semiconductor memory, holds data written by an induction electromagnetic field or radio waves, and can read and write data without contact”.

  The invention according to claim 9 is the electromagnetic flowmeter according to any one of claims 1 to 8, characterized in that the information carrier has a manufacturing number of the disposable housing, a manufacturing date, an expiration date, and other information for management. Have

[Invention of claims 1 to 3]
According to the first aspect of the present invention configured as described above, when the disposable housing is replaced, the information acquisition means provided in the base housing is changed from the information carrier provided in the disposable housing to the inner diameter dimension of the measurement channel. Dispos-specific data that can change according to variations and / or specification changes is acquired. Then, the calculation processing unit calculates the flow rate by reflecting the disposable unique data acquired from the information carrier through the information acquisition means in the flow rate calculation coefficient.

  As described above, when the disposable housing is replaced with a new one, the flow rate is calculated by reflecting new disposable specific data that can change according to the inner diameter of the measurement flow path, so that the flow rate can be measured accurately.

Specifically, as in the invention of claim 2, the inner diameter dimension of the measurement channel is provided as disposable inherent data, the inner diameter dimension of the measurement channel is D, the magnetic flux density applied to the liquid is B, When the constant is k and the flow rate calculation coefficient is C1, the following equation:
C1 = (π · D) / (4k · B)
The inner diameter dimension as the disposable specific data is reflected in the flow rate calculation coefficient C1 determined by, and the flow rate is calculated by multiplying the flow rate calculation coefficient C1 by the induced voltage.

Further, as in the invention of claim 3, when the inner diameter dimension of the measurement channel is D, the magnetic flux density applied to the liquid is B, the predetermined constant is k, and the flow rate calculation coefficient is C1, the information carrier Is the following formula:
C1 = (π · D) / (4k · B)
The flow rate calculation coefficient C1 determined by the above is provided as disposable unique data, and the calculation processing unit may calculate the flow rate by multiplying the induced voltage by the flow rate calculation coefficient C1 acquired as the disposable unique data.

[Inventions of Claims 4 and 5]
According to the invention of claim 4, the arithmetic processing unit calculates the flow rate by reflecting, in the flow rate calculation coefficient, base unique data that can change according to variations between base housings and / or specification changes from the base data storage unit. To do. That is, the flow rate calculation coefficient reflects both the disposable specific data and the base specific data, so that the flow rate can be measured more accurately.

  Specifically, as in the invention of claim 5, two types of actual measurement values for calibration or two types of measurement values measured under the same conditions using a base housing that is normally used and a base housing for reference are used. The ratio of the actual values for calibration is stored as the base specific data, and the arithmetic processing unit calculates the ratio obtained from the two types of actual values for calibration as the base specific data or the two types of actual values for calibration as the base specific data. The flow rate calculation coefficient may be corrected by multiplying the ratio by the flow rate calculation coefficient.

[Invention of claim 6]
According to the invention of claim 6, when the disposable housing is replaced and a new disposable housing is mounted on the base housing, the liquid with the zero flow rate is filled with the liquid in the measurement flow path to make the flow rate zero. In contrast, the induced voltage actually detected by the detection electrode is stored in the zero point data update storage means as zero point data. That is, each time the disposable housing is replaced, new zero point data corresponding to the relative position between the detection electrode and the electromagnetic coil is updated. After that, when the liquid flows in the measurement channel, the zero point correction is performed by subtracting the latest zero point data stored in the zero point data update storage means from the induced voltage actually detected by the detection electrode. The flow rate is calculated by multiplying the point-corrected induced voltage by a flow rate calculation coefficient. Thereby, even if the relative position of the detection electrode and the electromagnetic coil is shifted from the normal position in accordance with the replacement of the disposable housing, the flow rate of the liquid can be accurately measured.

[Invention of Claim 7]
If the information carrier is a bar code as in the seventh aspect of the invention, an increase in the size of the disposable housing accompanying the provision of the information carrier in the disposable housing can be prevented. In addition, since the barcode and the barcode reader are arranged on the opposite sides of the disposable housing attached to the base housing, only the disposal-specific data of the disposable housing attached to the base housing can be reliably processed. To be acquired. In other words, the barcode reader is prevented from erroneously reading the disposable unique data of other disposable housings that are not attached to the base housing.

[Invention of Claim 8]
According to invention of Claim 8, the freedom degree of arrangement | positioning of an information carrier and an information acquisition means improves. Here, if the RF tag and the tag reader are arranged in a portion facing each other with the disposable housing mounted on the base housing, only the disposal-specific data of the disposable housing mounted on the base housing can be reliably processed. To be acquired. In other words, the tag reader is prevented from erroneously reading the disposable unique data of other disposable housings that are not attached to the base housing.

[Invention of claim 9]
According to the ninth aspect of the invention, it is possible to perform quality control and inventory management of the disposable housing using the manufacturing number, manufacturing date, expiration date, and other management information of the disposable housing.

[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the electromagnetic flow meter 30 of the present embodiment includes a control unit 35 and a flow rate sensor 31, and is used for measuring the flow rate of liquids such as dialysate, blood, urine, and the like.

  The flow sensor 31 includes a measuring pipe 26 through which a liquid flows, an electromagnetic coil 32 that applies a magnetic flux across the measuring pipe 26 from the side of the measuring pipe 26, and a pair that is opposed to each other in a direction orthogonal to the magnetic flux. Detection electrodes 33, 33. The electromagnetic coil 32 is excited by an excitation circuit 34 provided in the control unit 35, and in this state, an induced voltage generated by a liquid flowing through an internal region of the measurement pipe 26 (hereinafter referred to as “measurement flow path 26A”) It is detected by a pair of detection electrodes 33 and 33.

  The induced voltage detected by the detection electrode 33 is amplified and A / D converted by the signal conversion circuit 36 and taken into the MPU 38 provided in the control unit 35. Then, the MPU 38 executes a predetermined program stored in the second memory 37B (for example, ROM), and integrates the flow rate (flow rate per unit time) and the flow rate over a predetermined time based on the induced voltage. Calculate the integrated flow rate. Further, the MPU 38 writes the calculation result in the first memory 37A (for example, RAM or EEPROM) provided in the control unit 35.

  The flow sensor 31 described above is divided into a clamp portion 40 (corresponding to the “base housing” of the present invention) and a disposable housing 50 that is detachably held with respect to the clamp portion 40.

  As shown in FIG. 2, the disposable housing 50 includes a flat block-like body 51, and the body 51 is integrally provided with a measuring pipe 26. The measurement pipe 26 is made of, for example, an inflexible resin having an insulating property. Both ends of the measuring pipe 26 protrude from the body 51, and one ends of tubes 24 and 24 through which liquid flows are connected. The other ends of these tubes 24 and 24 are connected to a predetermined medical instrument (for example, a dialysate bag, a blood transfusion bag, a urine bag, a catheter inserted into the patient's body, etc.).

  As shown in FIG. 2, the detection electrodes 33, 33 are substantially rod-shaped, and are provided integrally with the measurement pipe 26 by insert molding. One end of each of the detection electrodes 33, 33 penetrates inward and outward from the opposite direction of the side surface of the measurement pipe 26, and its tip is exposed in the measurement flow path 26A and is flush with the inner surface of the measurement pipe 26. Yes. As a result, the liquid passing through the measurement flow path 26 </ b> A comes into direct contact with the detection electrodes 33 and 33. Further, the other end portions of the detection electrodes 33, 33 protrude laterally from the body 51.

  A barcode 52 (specifically, a one-dimensional barcode) as an “information carrier” of the present invention is printed on one side surface of the body 51 in the flat direction of the disposable housing 50. In the barcode 52, the inner diameter dimension of the measurement flow path 26A measured in advance with a pin gauge or the like is recorded for each disposable housing 50 or for each predetermined number of product lots, as the disposable unique data of the present invention. Information for management such as the serial number, date of manufacture, and expiration date of use of the disposable housing 50 is recorded. As will be described later, the flow rate calculation coefficient is determined using the inner diameter dimension of the measurement flow path 26A, and quality management and inventory management of the disposable housing 50 are performed using management information. Note that the inner diameter dimension of the measurement channel 26A may be actually measured by a known hole diameter measuring device using a camera or the like.

  Next, the clamp part 40 will be described. The clamp unit 40 incorporates the electromagnetic coil 32 and the signal conversion circuit 36 (see FIG. 1), and is provided at the tip of the cable 60 extending from the control unit 35 (see FIG. 3). The clamp portion 40 is configured to sandwich the disposable housing 50 in the flat direction of the body 51. In addition, the freedom degree of arrangement | positioning of the clamp part 40 and the control part 35 improves by connecting between the clamp part 40 and the control part 35 with the cable 60. FIG.

  As shown in FIG. 3, the clamp portion 40 is formed by connecting a base body 41 and a cover body 42 with a hinge 46, and the base body 41 and the cover body 42 are opposed to each other when the clamp portion 40 is closed. Fitting recesses 43 and 43 that are fitted to the disposable housing 50 are respectively formed. Of the fitting recesses 43 formed in the base body 41, connection terminals 45, 45 for conducting and connecting the detection electrodes 33, 33 and the clamp part 40 to the lateral grooves 44 in which the detection electrodes 33, 33 are fitted. Is provided. The induced voltage detected by the detection electrodes 33 and 33 is input to the control unit 35 via the connection terminals 45 and 45 of the clamp unit 40. Note that a locking means 49 (specifically, a protrusion) for holding the clamp portion 40 in a closed state is provided on the side opposite to the side on which the hinge 46 of the base body 41 and the cover body 42 is provided. 49A and a locking claw 49B) that can be locked to the projection 49A.

  Now, in the clamp part 40, the base body 41 has a barcode reader 47 for reading information recorded on the barcode 52 (inner diameter dimensions of the measurement flow path 26A, information for management) (“ Corresponding to "information acquisition means". The barcode reader 47 is disposed in the fitting recess 43 of the base body 41 at a position facing the barcode 52 printed on the body 51 in a state where the disposable housing 50 is mounted on the clamp portion 40. The barcode reader 47 optically scans the barcode 52 and outputs the scan data. The scan data is decoded by the decoder 48 provided in the control unit 35 and read into the MPU 38. Here, since the barcode 52 and the barcode reader 47 are opposed to each other in a state where the disposable housing 50 is attached to the clamp portion 40, information on the disposable housing 50 attached to the clamp portion 40 (measurement flow channel 26A). Only the inner diameter dimension and the information for management) are reliably acquired by the MPU 38. In other words, the barcode reader 47 is prevented from erroneously reading information on other disposable housings 50 that are not attached to the clamp unit 40. The above is the description of the clamp part 40.

  Here, in the electromagnetic flow meter 30 of the present embodiment, the disposable housing 50 having the measurement pipe 26 and the detection electrodes 33 and 33 that are in contact with the liquid (dialysis fluid, blood, urine, etc.) of the flow sensor 31 is reused. The clamp part 40 which can be made disposable without being in contact with the liquid can be used repeatedly. In this way, the electromagnetic flow meter 30 can always be used in a sanitary manner, and the running cost can be reduced as compared with the case where the entire flow sensor 31 is made disposable.

  Next, operation | movement of the electromagnetic flowmeter 30 of this embodiment is demonstrated. When measuring the flow rate of the liquid using the electromagnetic flow meter 30, first, a new disposable housing 50 is attached to the clamp unit 40 and the flow sensor 31 is assembled. Specifically, the clamp portion 40 is opened, the disposable housing 50 is fitted into the fitting recess 43 of the base body 41, and the clamp portion 40 is closed. As a result, the disposable housing 50 is held between the base body 41 and the cover body 42 and held by the clamp portion 40. At this time, both end portions of the measuring pipe 26 are exposed from the clamp portion 40, and the barcode 52 printed on the body 51 and the barcode reader 47 provided in the clamp portion 40 are arranged to face each other (see FIG. 4). This completes the assembly of the flow sensor 31. Note that unused tubes 24 and 24 are connected in advance to both ends of the measurement pipe 26 exposed from the clamp portion 40.

  Next, a power switch (not shown) provided in the control unit 35 is operated to turn on the electromagnetic flow meter 30. Then, the electromagnetic flow meter 30 automatically enters the coefficient determination mode. Specifically, information (the inner diameter dimension of the measurement channel 26A, information for management) recorded in the barcode 52 is read by the barcode reader 47 and decoder 48 provided in the clamp unit 40. The MPU 38 stores the information in the first memory 37A and displays it on the display device 39. That is, the inner diameter dimension of the measurement channel 26A, the serial number of the disposable housing 50, the date of manufacture, the expiration date, etc. are stored in the first memory 37A and displayed on the display device 39. Here, when information (inner diameter dimension of the measurement channel 26A, information for management) cannot be acquired from the barcode 52 (for example, when the barcode 52 and the barcode reader 47 are not opposed to each other, When the code 52 is soiled), it is preferable to make the measurement impossible. In such a case, it is preferable to perform warning notification (for example, display a warning message on the display device 39).

Of the information read from the barcode 52 through the barcode reader 47, the MPU 38 reflects the inner diameter dimension of the measurement channel 26A in the flow rate calculation coefficient determined by the following equation (1). That is, when the flow rate calculation coefficient is C1, the inner diameter dimension of the measurement channel 26A is D, the magnetic flux density applied to the liquid is B, and the predetermined constant is k, the MPU 38
C1 = (π · D) / (4k · B) (1)
The flow rate calculation coefficient C1 is calculated by substituting the inner diameter dimension D of the measurement channel 26A read from the barcode 52 into the calculation formula (1), and the flow rate calculation coefficient C1 is stored in the first memory 37A. Here, it is assumed that the magnetic flux density B and the constant k are constant values obtained in advance by actual measurement or calculation. This completes the coefficient determination mode.

  When the coefficient determination mode ends, the electromagnetic flow meter 30 automatically switches to the zero point setting mode. In the zero point setting mode, the measurement flow path 26A is filled with liquid and the flow rate is forcibly held at “0”. For example, when the measurement channel 26A is filled with the liquid, the tubes 24 and 24 on the upstream side and the downstream side of the measurement pipe 26 are closed so that the liquid does not flow.

  In this state, the induced voltage in the measurement flow path 26A is detected by the detection electrodes 33, 33. The detected induced voltage is input to the MPU 38 via the signal conversion circuit 36. The MPU 38 stores / updates this induced voltage in the first memory 37A as the latest zero point data actually detected by the detection electrodes 33, 33 for the liquid having a zero flow rate. This is the end of the zero point setting mode. The processing executed by the MPU 38 in the first memory 37A, the MPU 38, and the zero point setting mode corresponds to “zero point data update storage unit”.

  When the zero point setting mode ends, the electromagnetic flow meter 30 automatically switches to the measurement mode. That is, for example, the tubes 24 and 24 on the upstream side and the downstream side of the measurement pipe 26 are both opened. Then, liquid flows in the measurement flow path 26A, and an induced voltage is generated when it passes through the measurement flow path 26A. This induced voltage is detected by the pair of detection electrodes 33, 33 and input to the MPU 38 via the signal conversion circuit 36. At this time, the MPU 38 performs zero point correction on the input induced voltage. That is, the zero point data stored in the first memory 37A is read, and the zero point data is subtracted from the induced voltage actually detected by the detection electrodes 33 and 33. Then, the flow rate per unit time and the integrated flow rate of the liquid are calculated by multiplying the induced voltage corrected with the zero point by the flow rate calculation coefficient C1 determined in the coefficient determination mode. The flow rate per unit time and the integrated flow rate are output to, for example, the first memory 37A and the display device 39. The MPU 38 corresponds to the “arithmetic processing unit” and “zero point correction unit” of the present invention.

  When the flow rate measurement is completed, the clamp unit 40 is opened, the used disposable housing 50 is removed, and the tubes 24 and 24 are discarded. In the next flow rate measurement, the clamp portion 40 of the flow rate sensor 31 is reused, and the disposable housing 50 is replaced with a new one. When the flow rate is measured using the new disposable housing 50, the coefficient determination mode and the zero point setting mode described above are performed again, and then the mode is switched to the measurement mode. That is, a new flow rate calculation coefficient C1 is calculated based on the inner diameter dimension D of the measurement flow path 26A provided in the new disposable housing 50, and the flow rate is calculated using the new flow rate calculation coefficient C1.

  As described above, according to the present embodiment, when the disposable housing 50 mounted on the clamp unit 40 is replaced, the barcode reader 47 provided on the clamp unit 40 performs measurement from the barcode 52 printed on the new disposable housing 50. The inner diameter dimension D of the flow path 26A is read, and the MPU 38 calculates the flow rate calculation coefficient C1 by substituting the inner diameter dimension D into the calculation formula (1). The MPU 38 calculates the liquid flow rate by multiplying the flow rate calculation coefficient C1 by the induced voltage E detected by the detection electrodes 33, 33. That is, each time the disposable housing 50 is replaced with a new one, a new flow rate calculation coefficient C1 corresponding to the inner diameter D of the measurement flow path 26A provided in the new disposable housing 50 is determined, and the flow rate calculation coefficient C1 is used. Since the liquid flow rate is calculated, the flow rate can always be accurately measured.

  In addition, since the induced voltage actually detected by the detection electrodes 33 and 33 in the measurement mode is corrected to zero, the relative position between the detection electrodes 33 and 33 and the electromagnetic coil 32 is changed as the disposable housing 50 is replaced. Even if it deviates from the normal position, the flow rate can be accurately measured.

  Furthermore, the electromagnetic flow meter 30 of the present embodiment is not limited to the manufacturing variation of the inner diameter as described above, and has the same effect even when the inner diameter dimension is changed by design such as a specification change. For example, when a plurality of types of disposable housings 50 having different inner diameter dimensions of the measurement flow path 26A are manufactured, and the disposable housing 50 having an optimum inner diameter dimension is selected from those according to the flow rate of the liquid and used. However, if the inner diameter dimension of the measurement channel 26A is recorded on the barcode 52 and attached to the disposable housing 50, the flow rate calculation coefficient is determined based on the inner diameter dimension when the clamp section 40 is mounted, and the flow rate calculation is performed. Since the flow rate is calculated using the coefficient, the flow rate can be accurately measured.

[Second Embodiment]
The present embodiment is mainly configured so that the flow rate is calculated by reflecting the base unique data that can change according to the variation between the clamp portions 40 and / or the specification change in the flow rate calculation coefficient. Different from the embodiment. Since other configurations are the same as those in the first embodiment, the same reference numerals are given to the same configurations, and duplicate descriptions are omitted.

  In the electromagnetic flow meter 30 of the present embodiment, the ratio of the two kinds of calibration actual measurement values T1, T2 is stored in the first memory 37A of the control unit 35 as the base specific data. The two kinds of calibration actual values T1 and T2 are measured as follows.

That is, the flow rate sensor 31 is configured by mounting the reference disposable housing 50S to the reference clamp portion 40S. Then, a liquid is caused to flow through the measurement flow path 26A at a known flow rate Q1, and the following equation is obtained from the measured value of the induced voltage E1 at that time
T1 = Q1 / E1 (2)
The first actual measurement value T1 for calibration determined by.

Here, the magnetic flux density imparted to the liquid by the reference clamp part 40S is Bs, the inner diameter dimension of the measurement flow path 26A provided in the reference disposable housing 50S is Ds, and the reference clamp part 40S is used. When the predetermined constant at the time is ks, the first actual measurement value T1 for calibration is
T1 = Q1 / E1 = (π · Ds) / (4ks · Bs) (3)
It can be expressed by the above relational expression. The predetermined constant ks reflects, for example, the amplification factor of the detection signal in the signal conversion circuit 36 provided in the reference clamp unit 40S.

The second calibration actual value T2 is as follows. In other words, the reference disposable housing 50S is mounted on the clamp unit 40 that is normally used to form the flow rate sensor 31, and a liquid is caused to flow through the measurement flow path 26A at a known flow rate Q1, and the induced voltage E2 at that time is measured. In other words, the induced voltage E2 is actually measured under the same conditions as when the first calibration actual measurement value T1 was obtained using the clamp unit 40 that is normally used for the flow sensor 31, and the following equation:
T2 = Q1 / E2 (4)
The second calibration actual value T2 determined by is obtained.

Here, if the magnetic flux density imparted to the liquid by the clamp part 40 that is normally used is B, and the predetermined constant when the clamp part 40 is used is k, the second measured value T2 for calibration is
T2 = Q1 / E2 = (π · Ds) / (4k · B) (5)
It can be expressed by the above relational expression. The predetermined constant k reflects, for example, the amplification factor of the detection signal in the signal conversion circuit 36 provided in the clamp unit 40 that is normally used.

In the first memory 37A of the control unit 35, the following formula H = T2 / T1 = (ks · Bs) / (k · B) (6)
The ratio H between the two types of calibration actual values T1 and T2 determined by the above is stored as base specific data.

  Here, as described above, the measurement conditions for obtaining the two types of calibration actual measurement values T1 and T2 are as follows. As described above, the reference clamp unit 40S is used for the flow rate sensor 31, or the clamp unit 40 that is normally used is used. However, since the other conditions are the same, the ratio H between the two kinds of calibration actual measurement values T1 and T2 is “base specific data that can change according to variations between clamp portions and / or specification changes”. is there. That is, the ratio H between the two kinds of calibration actual measurement values T1 and T2 reflects a predetermined constant and a magnetic flux density that can change according to variations between the clamp portions and / or specification changes. The first memory 37A that stores the ratio H of the two types of calibration actual values T1 and T2 corresponds to the “base data storage unit” of the present invention.

Now, when the normally used disposable housing 50 is manufactured, the disposable housing 50 is mounted on the reference clamp portion 40S to constitute the flow sensor 31. Then, the liquid is caused to flow at the same known flow rate Q1 as when the actual measurement values T1 and T2 for calibration are measured in the measurement channel 26A, and the following equation is obtained from the induced voltage E3 measured at this time:
C2 = Q1 / E3 (7)
The flow rate calculation coefficient C2 determined by is calculated.

Here, when the inner diameter dimension of the measurement flow path 26A provided in the disposable housing 50 that is normally used is D, the flow rate calculation coefficient C2 is:
C2 = Q1 / E3 = (π · D) / (4ks · Bs) (8)
It can be expressed by the above relational expression. The flow rate calculation coefficient C2 is recorded in the barcode 52 as disposable unique data and attached to the disposable housing 50 of the same production lot. Here, as shown in the relational expression (8), the parameter for determining the flow rate calculation coefficient C2 includes the inner diameter dimension D of the measurement flow path 26A. It can be said that the data can change according to the variation in the inner diameter dimension of 26A and / or the specification change.

Now, at the time of normal flow measurement, the flow sensor 31 is comprised by the clamp part 40 and the disposable housing 50 which are normally used. Then, the flow rate calculation coefficient C <b> 2 is read from the barcode 52 printed on the disposable housing 50 by the barcode reader 47 provided in the clamp unit 40. The MPU 38 multiplies the flow rate calculation coefficient C2 by the ratio H of the calibration actual measurement values T1 and T2 stored in the first memory 37A to correct the flow rate calculation coefficient C2 as disposable inherent data. That is, when the correction value of the flow rate calculation coefficient C2 is Ch, the MPU 38 has the following equation:
Ch = C2 · H = (π · D / 4ks · Bs) · (ks · Bs / k · B)
= (Π · D) / (4k · B) (9)
The correction value Ch of the flow rate calculation coefficient C2 determined by is calculated.

  The MPU 38 calculates the flow rate Q by multiplying the induced voltage detected by the detection electrodes 33 and 33 and corrected for the zero point by the correction value Ch of the flow rate calculation coefficient.

  As described above, in the electromagnetic flow meter 30 of the present embodiment, the flow rate calculation coefficient C2 as the disposable inherent data that can be changed according to the variation in the inner diameter dimension of the measurement flow path 26A and / or the specification change is obtained between the clamp portions 40. The flow rate is calculated by correcting by the ratio H of the calibration actual values T1 and T2 as the base unique data that can change according to variations and / or specification changes, and multiplying the correction value Ch of the flow rate calculation coefficient C2 by the induced voltage. . That is, since the flow rate is calculated by reflecting the two specific data of the disposable specific data and the base specific data in the flow rate calculation coefficient, the flow rate can be measured more accurately.

[Other Embodiments]
The present invention is not limited to the above-described embodiment. For example, the embodiments described below are also included in the technical scope of the present invention, and various other than the following can be made without departing from the scope of the invention. It can be changed and implemented.

  (1) In the first and second embodiments, the bar code 52 is used as the information carrier. However, a so-called magnetic stripe may be used. Further, although the barcode 52 is a one-dimensional barcode, it may be a two-dimensional barcode (for example, a QR code (registered trademark)). When a two-dimensional barcode is used instead of the one-dimensional barcode, more information can be recorded than the one-dimensional barcode. Further, the barcode and the magnetic stripe may be printed directly on the disposable housing 50 as in the first embodiment, or may be printed on a sticker or the like and the sticker attached to the disposable housing 50.

  Further, the RF tag 70 may be used as an information carrier. As shown in FIG. 5, the RF tag 70 has a thin plate structure or a sheet structure including an IC chip 71 including a semiconductor memory and an antenna 72.

  The RF tag 70 is attached to one side surface of the body 51 of the disposable housing 50 with, for example, an adhesive tape or an adhesive. Further, the clamp unit 40 incorporates a tag reader (not shown). When the disposable housing 50 is attached to the clamp unit 40, the RF tag 70 and the tag reader come close to each other. When radio waves are transmitted from the tag reader in this state, the antenna 72 provided in the RF tag 70 receives the radio waves, and information stored in the semiconductor memory from the IC chip 71 (dispos specific data, management information) Is output. This information is received by the tag reader and given to the MPU 38. As in the first embodiment, the MPU 38 measures the flow rate by reflecting the disposable specific data (inner diameter dimension of the measurement flow path 26A) included in the information in the flow rate calculation coefficient.

  It is preferable that the RF tag 70 and the tag reader are arranged at portions facing each other with the disposable housing 50 mounted on the clamp portion 40, but the present invention is not limited to this, and the information stored in the RF tag 70 is stored in the tag reader. As long as it is readable, it may be disposed in any part of the disposable housing 50 and the clamp part 40. In addition, the RF tag 70 is usually disposable together with the disposable housing 50, but may be peeled off from the disposable housing 50 and reused.

  Normally, as described above, the commercially available RF tag 70 is attached to the disposable housing 50, but the following may be used. For example, as shown in FIG. 6, an IC chip 71 and an antenna 72 may be built in the body 51 to manufacture the disposable housing 50 in which the body 51 itself functions as an RF tag.

  By the way, when barcodes and magnetic stripes are used as information carriers, there is a risk that information may be erroneously read or cannot be read due to adhesion of dirt on the printing surface of the barcodes and magnetic stripes. On the other hand, if the RF tag 70 is used, such a problem is solved, and more information can be stored than the barcode and the magnetic stripe. In addition, if the information carrier and the information acquisition means are configured by the RF tag 70 and the tag reader, information can be acquired from a distant location, compared with the case where the barcode 52 and the barcode reader 47 are configured. The degree is improved.

  (2) In the first embodiment, the inner diameter dimension D of the measurement flow path 26A is recorded in the barcode 52 as the disposable unique data, and the MPU 38 uses the inner diameter dimension D read from the barcode 52 as the arithmetic expression (1). ) And is reflected in the flow rate calculation coefficient C1 and the flow rate is calculated by multiplying the flow rate calculation coefficient C1 by the induced voltage.

That is, when the inner diameter dimension of the measurement flow path is D, the magnetic flux density of the magnetic field is B, the predetermined constant is k, and the flow rate calculation coefficient is C1, the barcode 52 has the following formula:
C1 = (π · D) / (4k · B)
The flow rate calculation coefficient C1 determined by the above is recorded in the barcode 52 as disposable unique data, and the MPU 38 may calculate the flow rate by multiplying the induced voltage by this flow rate calculation coefficient C1 acquired through the barcode reader 47.

  (3) In the second embodiment, the first memory 37A stores the ratio H of the two types of calibration actual values T1 and T2 as the base unique data. However, the first calibration actual value T1 And the second actual measurement value T2 for calibration may be stored as base specific data, and the MPU 38 may obtain the ratio H from the two types of actual measurement values T1 and T2 for calibration as the base specific data.

  (4) In the first embodiment, when the MPU 38 cannot acquire information from the barcode 52, the flow rate is disabled to be measured. For example, the MPU 38 periodically performs the flow rate measurement (during the measurement mode). For example, information may be acquired from the barcode 52, and when information cannot be acquired, for example, when the clamp unit 40 is opened and the disposable housing 50 is removed, measurement may be disabled.

  (5) In the first and second embodiments, dialysate, blood, and urine are exemplified as the liquid for measuring the flow rate with the electromagnetic flow meter 30. However, the liquid may be used for measuring the flow rate of other liquids such as water.

  (6) In the first and second embodiments, the clamp unit 40 includes the electromagnetic coil 32 and the signal conversion circuit 36. However, the clamp unit 40 includes only the electromagnetic coil 32, and the signal conversion circuit 36 includes: The control unit 35 may be provided. In this way, the clamp unit 40 can be made compact.

  (7) In the first and second embodiments, the clamp unit 40 includes the barcode reader 47. However, the clamp unit 40 may include the decoder 48 in addition to the barcode reader 47.

  (8) In the first and second embodiments, signals are transmitted and received between the control unit 35 and the clamp unit 40 via the cable 60. However, wireless communication may be used.

  (9) In the first and second embodiments, the measuring pipe 26 is made of an insulating resin, but may be made of an insulating ceramic. Alternatively, the measuring pipe 26 may be made of metal and an insulating film may be formed on the inner surface.

  (10) In the first and second embodiments, the disposable data and management information are written in the barcode 52, but other information such as the temperature, pressure, conductivity and induced voltage of the liquid is used. Information such as the relationship may be written.

  (11) In the first and second embodiments, when the electromagnetic flow meter 30 is turned on, the coefficient determination mode, the zero point setting mode, and the measurement mode are switched in this order, but the zero point setting mode, You may comprise so that it may switch in order of coefficient determination mode and measurement mode. Further, mode switching may be performed manually instead of automatically.

  (12) In the first and second embodiments, the MPU 38 acquires information for managing the disposable housing 50 from the barcode 52. For example, the MPU 38 is unique to the disposable housing 50 used in the past. When an identification symbol (for example, a serial number) is stored in a nonvolatile memory provided in the control unit 35 and the same identification symbol as that stored in the nonvolatile memory is acquired again by the barcode reader 47 May perform warning notification (for example, display a warning message on the display device 39). If it does in this way, reuse of used disposable housing 50 can be prevented certainly.

Block diagram of the electromagnetic flow meter according to the first embodiment Disposable housing perspective view Perspective view of clamp part Perspective view of flow sensor The perspective view of the disposable housing which concerns on other embodiment (1). The perspective view of the disposable housing which concerns on other embodiment (1).

Explanation of symbols

26A Measurement flow path 30 Electromagnetic flow meter 31 Flow sensor 32 Electromagnetic coil 33, 33 Detection electrode 37A Memory (zero point data update storage means, base data storage section)
38 MPU (arithmetic processing unit, zero point correction unit)
40 Clamp part (base housing)
40S Reference clamp (Base housing for reference)
47 Bar code reader (information acquisition means)
50 Disposable housing 52 Bar code (information carrier)
70 RF tag (information carrier)

Claims (9)

A disposable disposable housing with a measurement channel through which the liquid passes;
A base housing to which the disposable housing is detachably mounted;
An electromagnetic coil that is provided in the base housing and applies a magnetic field to the liquid in the measurement channel;
A detection electrode provided in the disposable housing for detecting an induced voltage generated by the liquid passing through the measurement channel;
In an electromagnetic flow meter comprising an arithmetic processing unit that calculates the flow rate of the liquid by multiplying the induced voltage detected by the detection electrode by a flow rate calculation coefficient,
The disposable housing is provided with an information carrier having disposable specific data that can change according to variations in the inner diameter dimension of the measurement channel and / or changes in specifications,
The base housing is provided with information acquisition means capable of acquiring the disposable data from the information carrier in a state where the disposable housing is mounted,
The electromagnetic flowmeter, wherein the arithmetic processing unit calculates the flow rate by reflecting the disposable unique data acquired from the information carrier through the information acquisition unit in the flow rate calculation coefficient. The information carrier has the inner diameter dimension of the measurement channel as the disposable specific data, and the arithmetic processing unit sets the inner diameter dimension as D, sets the magnetic flux density of the magnetic field as B, and sets a predetermined constant as k, When the flow rate calculation coefficient is C1, the following equation:
C1 = (π · D) / (4k · B)
2. The flow rate is calculated by reflecting the inner diameter dimension D as the disposable inherent data in the flow rate calculation coefficient C1 determined by the equation, and multiplying the induced voltage by the flow rate calculation coefficient C1. Electromagnetic flow meter. When the inner diameter dimension of the measurement channel is D, the magnetic flux density of the magnetic field is B, the predetermined constant is k, and the flow rate calculation coefficient is C1, the information carrier has the following formula:
C1 = (π · D) / (4k · B)
, And having the flow rate calculation coefficient C1 determined by
The electromagnetic flowmeter according to claim 1, wherein the arithmetic processing unit calculates the flow rate by multiplying the induced voltage by the flow rate calculation coefficient C <b> 1 acquired as the disposable unique data.   A base data storage unit that stores base unique data that can change according to variations between the base housings and / or specification changes, and the arithmetic processing unit reflects the base unique data in the flow rate calculation coefficient. The electromagnetic flowmeter according to claim 1, wherein the flow rate is calculated. In the base data storage section, two types of actual measurement values for calibration or two types of actual measurement values for calibration that are measured under the same conditions using the base housing that is normally used and the base housing for reference are used. Is stored as the base specific data,
The arithmetic processing unit multiplies the flow rate calculation coefficient by a ratio obtained from two types of calibration actual values as the base specific data or a ratio of two types of calibration actual values as the base specific data, The electromagnetic flow meter according to claim 4, wherein the flow rate calculation coefficient is corrected. Zero point data update storage means for storing, as zero point data, the induced voltage actually detected by the detection electrode for the liquid with the zero flow rate when the flow rate of the liquid filling the measurement channel is zero. When,
Zero point correction for performing zero point correction by subtracting the latest zero point data stored in the zero point data update storage means from the induced voltage detected by the detection electrode when the liquid flows in the measurement channel The electromagnetic flow meter according to claim 1, further comprising: a portion.   The information carrier is a bar code, the information acquisition means is a bar code reader, and the bar code and the bar code reader are arranged at portions facing each other in a state where the disposable housing is mounted on the base housing. The electromagnetic flow meter according to claim 1, wherein the electromagnetic flow meter is provided.   The electromagnetic flowmeter according to claim 1, wherein the information carrier is an RF tag, and the information acquisition unit is a tag reader. 9. The electromagnetic flowmeter according to claim 1, wherein the information carrier includes a manufacturing number, a manufacturing date, a use period, and other management information of the disposable housing.

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