JP6045867B2 - Flow compensation device - Google Patents

Description

  The present invention is provided in a flow meter that measures and outputs a flow rate of a fluid to be measured, and an initial measured flow rate that is measured while reflecting an actual temperature and pressure state of the fluid to be measured is determined based on a reference temperature and a reference pressure. The present invention relates to a flow rate correction apparatus that corrects and outputs a measured flow rate in a reference state.

  When measuring the flow rate of a fluid under measurement whose volume changes due to changes in temperature or pressure, such as gas, with a flow meter, the initial measured flow rate is measured while reflecting the actual temperature and pressure state of the fluid under measurement. Is corrected to a measured flow rate in a reference state (for example, a standard state or a normal state) based on a reference temperature and a reference pressure, and is output in order to accurately control the flow rate of the fluid to be measured.

  Therefore, the flow rate of the fluid to be measured flowing through the measurement channel is calculated and output based on the flow rate measurement signal proportional to the flow rate or flow velocity of the fluid to be measured from the flow rate measurement mechanism provided in the measurement channel. The flow meter uses the initial measured flow rate that is measured while reflecting the actual temperature and pressure state of the fluid to be measured based on the flow rate measurement signal. A flow rate correction device for correcting the flow rate) is provided.

  In general, the flow rate correction device takes in the detection outputs of the temperature sensor and pressure sensor that detect the temperature state and pressure state of the fluid under measurement flowing through the measurement flow path, and the actual temperature of the fluid under measurement based on these detection outputs and Based on the change state of the pressure with respect to the reference state due to the reference temperature and the reference pressure, a correction coefficient (temperature, pressure correction coefficient) for correcting the initially measured flow rate to the measured flow rate of the reference state is calculated, and the initial measured flow rate is Based on the correction coefficient, the measurement flow rate is corrected to the reference state measured by the reference temperature and the reference pressure and output.

  For example, a rotor (flow measuring rotor) that rotates according to the flow of each unit volume flow of the fluid to be measured is placed in the measurement channel, and the rotation of the rotor is detected by a sensor and rotated as a flow measurement signal. In a positive displacement flowmeter having a flow rate measurement mechanism that transmits a flow rate pulse signal corresponding to the rotation of the child, the flow rate correction device is calculated by counting the flow rate pulse of the flow rate pulse signal transmitted from the flow rate measurement mechanism. The initial measured flow rate is corrected to the measured flow rate in the reference state by multiplying by the temperature / pressure correction coefficient obtained based on the detection output of each of the temperature sensor and the pressure sensor, and output to a device such as a flow rate indicator.

  On the other hand, in a flow meter provided with this type of flow correction device, a measurement unit housing containing the flow correction device is usually attached and fixed to a flow meter body provided with a measurement flow path and a flow measurement mechanism. It has an integrated housing structure. Accordingly, the flow meter body provided with the measurement flow path and the flow rate measurement mechanism is connected to the transfer path pipe through which the fluid to be measured flows so that the measurement flow path communicates with the flow meter main body. By using a flow rate correction device housed in an integral measurement unit housing, accurate flow rate management of the fluid to be measured can be performed at the site where the fluid to be measured is transferred.

  In this case, each part of the flow meter such as the flow measurement sensor of the flow measurement mechanism, the temperature sensor / pressure sensor for detecting the temperature / pressure state of the fluid to be measured flowing through the measurement flow path, and the flow correction device housed in the measurement unit housing Since there is a case where an external power source cannot be used as a drive power source at the site where the fluid to be measured is transferred, for example, a battery can be exchanged together with a flow rate correction device in the measurement unit housing, and this battery can be used as a drive power source. Thus, it is possible to operate regardless of the presence or absence of an external power source at the site where the fluid to be measured is transferred.

  As a prior art of such a flow rate correction apparatus using a battery for the drive power source, there is a flow rate correction apparatus described in Patent Document 1. In Patent Document 1, a sampling time setting unit that can arbitrarily set the sampling interval of the temperature / pressure state of the fluid to be measured by the temperature sensor and the pressure sensor is provided, and changes in the temperature state and pressure state of the fluid to be measured are small. If the sampling time setting means sets the sampling interval of the temperature / pressure state of the fluid to be measured long in advance, the number of calculations of the temperature / pressure correction coefficient by the flow rate correction device during sampling can be calculated. There is described a flow rate correction device that reduces the life of a battery as a drive power source for each part of the flow meter.

  Further, as a related art of a related device that is arranged in a transfer path like a flow meter and uses a battery as a driving power source, there is a gas cutoff device described in Patent Document 2. In Patent Document 2, as a method for detecting a decrease in the remaining amount of a battery as a driving power supply while preventing a transient temperature drop or an erroneous detection due to external noise, the battery voltage of the driving power supply (battery terminal voltage) is constant. It is monitored every period, and at each monitoring, it is determined whether or not the battery voltage has fallen below the specified value (battery consumption voltage). Techniques for detecting volume reduction are described. In addition, when the battery usage time measurement unit times the usage time of the battery as the drive power source, and the battery usage time determination unit exceeds the usage time limit set in advance by the battery usage time limit setting unit A time signal is output, and the display unit displays that the time signal has been output. For example, to a gas supplier or general user that the battery as a drive power source has exceeded a certain capacity and is near the end of its life. It is described that the specified number of times, which is a condition for detecting a decrease in the remaining battery level, is reduced to, for example, one.

JP-A-9-72771 Japanese Patent No. 4110554

  By the way, since the battery has the property that the magnitude of the electric power that can be taken out from the battery differs depending on the magnitude of the load current, when the magnitude of the load current changes, the relationship between the battery voltage and the remaining battery level is also before and after that. Change. That is, when a load current flows from a battery to a connected load, the battery has a tendency that the capacity of the battery decreases and the battery voltage decreases. The battery voltage drop at that time varies depending on the size of the load connected to the battery and the internal resistance of the battery, and also varies depending on the remaining battery level.

  Therefore, even if the battery voltage in the state where the connected load is not driven by the battery (no load current flows through the connected load) is higher than the specified value, the connected load When a load current flows in an attempt to actually drive the battery, the battery voltage may be greatly reduced and fall below a specified value, and the load may not be normally driven.

  For such an event, the flow correction device described in Patent Document 1 detects the temperature state and pressure state of the fluid under measurement when it is expected that the temperature state and pressure state of the fluid under measurement will be small. This is a technology that extends the battery life by setting a long sampling interval for capturing data and reducing the number of times the load is connected to the battery during sampling.

  Therefore, in the flow rate correction device described in Patent Document 1, even when the battery voltage in a state where the correction coefficient calculation processing other than at the time of sampling is not performed is higher than the specified value, In order to capture the temperature and pressure detection data of the fluid to be measured, the battery voltage is greatly reduced by the drive current at the moment when the load including the temperature detector and the pressure detector is connected to the battery and driven. May fall below the specified value. In that case, the flow rate correction process with an appropriate correction coefficient cannot be performed suddenly.

  In addition, in the gas shut-off device using a battery for the driving power source described in Patent Document 2 arranged in the transfer path as with the flow meter, the output of a time signal indicating that the battery exceeds a certain usage capacity and is near the end of its life is This is done indirectly by comparing the battery usage time with the expiration date. The expiration date is also a value obtained by converting the usage capacity of the battery, which causes a large variation in the rate of decrease in the battery voltage, into time based on the battery consumption used by the device every unit time.

  For this reason, in the gas shut-off device described in Patent Document 2, the state of decrease in the remaining battery level at the time of output of the timing signal is actually ambiguous, and the remaining battery level is the same as that of the gas shut-off device described in Patent Document 2. When applying this detection configuration to the flow rate correction device, at the time of the output of the timing signal that informs that the battery life is near, it is suddenly impossible to accurately calculate the correction coefficient, It is still unknown whether the correction coefficient calculation process can be performed accurately for the time being. In the former case, quick battery replacement is necessary in order to appropriately perform the correction coefficient calculation process. In the latter case, quick battery replacement hinders efficient consumption of battery capacity. become.

  In view of the above-described problems of the prior art, the present invention provides a flow rate correction device that efficiently consumes a battery as a driving power source and extends a period during which accurate flow rate management of a fluid to be measured can be performed. For the purpose.

  When correcting the initial measured flow rate measured while reflecting the actual temperature and pressure state of the fluid under measurement in the flow rate correction device, the initial measurement is sequentially calculated when correcting the measured flow rate to the reference state based on the reference temperature and reference pressure. In order to correct the flow rate to the measured flow rate in the reference state, it is necessary to periodically measure the actual temperature and pressure state of the fluid to be measured. When measuring the actual temperature / pressure state of the fluid to be measured, the temperature of the fluid to be measured is compared to the average power consumption used in the process of correcting the normal initial measured flow rate to the measured flow rate in the reference state. The power consumption for taking in the detection outputs of the temperature sensor and pressure sensor for detecting the state / pressure state is added.

  In order to solve the above-described problem, the flow rate correction device of the present invention is a battery as a driving power source, which is normally a load current that flows continuously, usually a load current that flows instantaneously. It is characterized in that the actual predetermined remaining amount of the battery as a drive source can be objectively and accurately grasped by controlling the consumption timing of the battery.

  That is, the flow rate correction device of the present invention takes in the battery voltage of the battery when the maximum load current flows through the device when the temperature sensor and the pressure sensor are driven synchronously, and the battery voltage is a predetermined voltage. In the case where it is detected that the following has occurred, a signal indicating that the battery life is approaching is output.

  As a result, in the flow rate correction apparatus of the present invention, the remaining battery level as the drive source has reached the predetermined battery level status, that is, the initial measured flow rate can be corrected to the measured flow rate in the reference state. However, in the periodic detection of the temperature and pressure of the fluid to be measured used for the correction, the actual condition of the battery as the drive source is defined as the temperature sensor / pressure sensor cannot be driven synchronously. A predetermined remaining amount status can be detected.

  As a result, in the flow correction device, the actual predetermined remaining amount of the battery as the drive source can be objectively and accurately grasped, and the battery can be efficiently consumed. Flow rate can be managed.

  In addition, the flow rate correction apparatus of the present invention takes in the battery voltage of the battery when the maximum load current flows through the apparatus when the temperature sensor and the pressure sensor are driven synchronously, and the battery voltage is predetermined. After detecting that the voltage has become lower than the voltage, the temperature sensor and the pressure sensor are driven asynchronously.

  Thereby, in the flow rate correction apparatus of the present invention, even after detecting the actual predetermined remaining amount status of the battery as the drive source, which is defined by being unable to drive the temperature sensor and the pressure sensor synchronously, By not driving the temperature sensor and pressure sensor at the same time, but shifting the drive timings to different times, the amount of decrease in battery voltage when the maximum load current flows through the device at the maximum power consumption, in other words, Therefore, the periodic measurement of the temperature state and the pressure state of the fluid to be measured, which is used when correcting the initially measured flow rate to the reference measured flow rate, can be continued.

  As a result, in the flow rate correction device, it is possible to efficiently draw out the remaining amount of the battery as the drive source, and to further increase the efficient consumption of the battery. Can be extended.

  According to the present invention, in the flow rate correction apparatus, it is possible to objectively and accurately grasp the actual predetermined remaining amount of the battery as a drive source, and to efficiently consume the battery. Accurate flow control can be performed.

  In addition, according to the present invention, in the flow rate correction device, it is possible to efficiently draw out the remaining amount of the battery as a drive source, thereby further increasing the efficient consumption of the battery, and the accurate flow rate of the fluid to be measured. The period during which management can be performed can be extended.

  Problems, configurations, and effects other than those described above will become apparent from the following description of embodiments.

1 is an overall configuration diagram of a roots flow meter as an example of a flow meter to which a flow rate correction device according to an embodiment of the present invention is applied. FIG. 2 is a cross-sectional view of the main body of the flow meter shown in FIG. 1 viewed in the II-II direction. 1 is a system configuration diagram of a flow rate correction apparatus according to an embodiment of the present invention. It is a flowchart of the flow volume correction process which the measurement calculating device of a flow volume correction apparatus performs. It is a flowchart of the correction data acquisition update process and correction control process which the measurement arithmetic unit of a flow volume correction apparatus performs. It is the figure which showed the time transition of the power consumption and battery voltage in a flow volume correction apparatus. It is a flowchart of the modification of the correction data acquisition update process shown in FIG. 5, and a correction control process.

Hereinafter, the configuration and operation of an embodiment of a flow rate correction apparatus according to the present invention will be described with reference to the drawings.
FIG. 1 is an overall configuration diagram of a roots flow meter as an example of a flow meter to which a flow rate correction apparatus according to an embodiment of the present invention is applied.
2 is a cross-sectional view of the main body of the flow meter shown in FIG. 1 as viewed in the II-II direction.

  In FIG. 1, a roots flow meter 1 has a configuration in which a measurement unit housing 3 that is schematically represented by being surrounded by a broken line is integrally attached and fixed to a flow meter body 2 that is represented by a cross-sectional view. Yes.

  As shown in FIGS. 1 and 2, the flowmeter main body 2 has a measurement channel 5 formed in the casing 4 in which the inlet 4 a and the outlet 4 b are opened so that the inlet 4 in and the outlet 4 out communicate with each other. Has been. A measuring chamber 6 is formed in the middle of the measurement channel 5.

  The weighing chamber 6 is provided with a pair of eyebrows (roots) type rotors 7 a and 7 b that constitute a flow rate measuring mechanism with the roots flow meter 1. Rotating shafts 8a and 8b are fixed to the eyebrows-shaped rotors 7a and 7b, and the rotating shafts 8a and 8b can be rotated integrally with the rotors 7a and 7b by bearings 9 and 9 formed on the casing 4. It is supported. Then, at both ends of the rotary shafts 8a and 8b, the fluid to be measured is prevented from leaking out of the measuring chamber 6 by the seal mechanisms 10 and 10 provided in the portion around the shaft between the measuring chamber 6 and the bearings 9 and 9. It is led out to the side part of the casing 4 outside the measuring chamber 6 while maintaining airtightness. Each end part of the rotating shafts 8a and 8b led out to the side part of the casing 4 is covered with the side lids 11 and 11 attached to the corresponding side part of the casing 4, and is hidden from the outside.

  Timing gears 12a and 12b that mesh with each other are provided on one end side that is led out of the measuring chamber 6 of each of the rotary shafts 8a and 8b. As a result, the eyebrows-shaped rotors 7a, 7b transmit a rotational driving force to each other via the timing gears 12a, 12b fitted on one end side of the rotating shafts 8a, 8b, thereby a pair of eyebrows-shaped rotors. 7a and 7b have a phase difference of 90 degrees, respond to the flow of the fluid to be measured, and rotate at the number of revolutions according to the flow rate of the fluid to be measured, and the peripheral surface of the partner eyebrow rotor and the inner wall surface of the measuring chamber 6 However, it is configured to rotate smoothly while maintaining a small clearance.

  When the fluid to be measured flows through the measurement flow path 5 of the casing 4 from the inlet 4in to the outlet 4out, the pair of eyebrows-shaped rotors 7a and 7b rotate in the A and B directions as shown in FIG. At that time, the fluid transfer space S shown by hatching in FIG. 2 is formed by the peripheral surfaces of the rotors 7a and 7b and the inner wall surface of the measuring chamber 6, and this fluid is rotated along with the rotation of the rotors 7a and 7b. A fluid to be measured corresponding to the volume in the transfer space S is sent to the outlet 4out side.

  In order to detect the rotation of the rotors 7a and 7b at that time, the rotation of the eyebrows-shaped rotor 7a is provided at the other end led out of the measuring chamber 6 of one of the rotation shafts 8a and 8b. A magnet 13 as a detection element for detection is fixed. A magnetic sensor 14 for detecting the rotation of the magnet 13 accompanying the rotation of the rotating shaft 8a is disposed on the back surface of the corresponding side lid 11 so as to face the magnet 13. The magnetic sensor 14 detects a change in magnetic flux generated when the magnet 13 rotates together with the rotating shaft 8a, and converts it into an electrical signal for output. The magnet 13 and the magnetic sensor 14 detect the rotation of the eyebrows-shaped rotor 7a that responds to the flow of the fluid to be measured as a flow rate detection unit in the flow rate measurement mechanism. The electric signal output from the magnetic sensor 14 corresponds to the flow measurement signal of the fluid to be measured. In the illustrated roots flow meter 1, the flow rate measurement signal corresponds to a flow rate pulse signal corresponding to the flow of each unit flow rate of the fluid to be measured.

  In addition, a pressure sensor 15 that detects the pressure of the fluid to be measured is provided in the inflow path that communicates between the inlet 4 in of the casing 4 and the measuring chamber 6. For the pressure sensor 15, for example, a semiconductor diffusion strain gauge or the like is used.

  In addition, a temperature sensor 16 for detecting the temperature of the fluid to be measured is provided in the outflow passage that communicates between the measuring chamber 6 of the casing 4 and the outlet 4out. For the temperature sensor 16, for example, a platinum resistance thermometer or the like is used.

  A magnetic sensor 14 as a flow rate detection unit, a pressure sensor 15 as a pressure detection unit of a fluid to be measured, and a temperature sensor 16 as a temperature detection unit provided in the flow meter body 2 are accommodated in the measurement unit housing 3. The flow rate correction device 24 is connected by wiring.

  On the other hand, the measurement unit housing 3 is provided with a battery 21, a flow rate indicator 22, a sampling time setting unit 23, and a flow rate correction device 24.

  The battery 21 supplies drive power to each part of the electric drive unit of the roots flow meter 1 including the flow rate indicator 22 and the flow rate correction device 24. Therefore, the battery 21 is connected to the flow rate indicator 22 and the flow rate correction device 24 through the power supply line. For example, a lithium battery, a dry battery, or the like is used as the battery 21.

  The flow rate indicator 22 is connected to the flow rate correction device 24 and displays measurement information such as an instantaneous flow rate and an integrated flow rate of the fluid to be measured flowing through the measurement flow path 5. Therefore, the flow rate indicator 22 is accommodated in the measurement unit casing 3 with its display surface facing outside from a display window formed in the measurement unit casing 3.

  The sampling time setting unit 23 is connected to the flow rate correction device 24 and adjusts and sets the sampling interval of the temperature / pressure state of the fluid to be measured by the pressure sensor 15 and the temperature sensor 16 by operating the operation unit.

  The flow rate correction device 24 uses the pressure sensor 15 to calculate the initial measured flow rate measured while reflecting the actual temperature and pressure state of the fluid to be measured based on the flow rate measurement signal supplied from the magnetic sensor 14 as the flow rate detection unit. Based on the pressure of the fluid to be measured detected by the temperature sensor and the temperature of the fluid to be measured detected by the temperature sensor 16, the flow rate is corrected to the measured flow rate in the reference state (measured flow rate in the standard state) by the reference temperature and the reference pressure.

FIG. 3 is a system configuration diagram of the flow rate correction apparatus shown in FIG.
The flow rate correction device 24 includes a measurement calculation device 31, a flow rate detection sensor I / F (interface) circuit 32, a pressure sensor I / F circuit 33, a temperature sensor I / F circuit 34, an internal power supply circuit 35, a battery. A voltage monitoring circuit 36, an input circuit 37, and an output circuit 38 are included.

  The measurement calculation device 31 is configured by a microcomputer, and controls the other part of the flow rate correction device 24 to perform flow rate correction calculation control processing such as flow rate correction processing, correction data acquisition update processing, correction control processing, and the like.

  The measurement calculation device 31 corrects the initial measurement flow rate measured while reflecting the actual temperature and pressure state of the fluid to be measured to the measurement flow rate in the reference state (measurement flow rate in the standard state) based on the reference temperature and the reference pressure. Flow correction processing is performed as needed.

  In addition to the flow rate correction process described above, the measurement calculation device 31 periodically acquires and updates correction data used for correcting the initial measured flow rate to the measured flow rate in the reference state in the flow rate correction process. The acquisition update process (hereinafter also referred to as sampling process) is performed periodically. In the correction data acquisition / update process, the correction data is acquired again based on the actual pressure and temperature of the current fluid to be measured, and updated by replacing the correction data used in the previous flow rate correction process.

  Further, the measurement calculation device 31 monitors a decrease in the remaining amount of the battery 21 as a drive power source, and the remaining amount of the battery 21 is less than a preset specified value, so that the life of the battery 21 is approaching. When it is detected, a correction control process is performed to change the periodic correction data acquisition method in the correction data acquisition update process.

  In the measurement arithmetic unit 31, the magnetic sensor 14 as a flow rate detection unit is passed through a flow rate detection sensor I / F circuit 32, the pressure sensor 15 is passed through a pressure sensor I / F circuit 33, and the temperature sensor 16 is a temperature sensor I. They are connected via the / F circuit 34. The measurement operation device 31 is configured to take in a flow rate pulse, a detected pressure of the measured fluid, and a detected temperature of the measured fluid as a flow measurement signal of the measured fluid through these.

  The flow rate detection sensor I / F circuit 32 always drives the magnetic sensor 14 as a flow rate detection unit, and shapes the detection signal of the magnetic sensor 14 that reflects the flux linkage of the magnet 13 that rotates together with the rotating shaft 8a. Then, a flow rate pulse signal corresponding to the flow of each unit flow rate of the fluid to be measured is taken out.

  The pressure sensor I / F circuit 33 drives the pressure sensor 15 that detects the pressure of the fluid to be measured at the time of sampling, and A / D converts the detection signal of the pressure sensor 15 to obtain the pressure value of the fluid to be measured. Extract as a compatible digital signal.

  The pressure sensor I / F circuit 33 is configured not to supply a drive current or a drive voltage to the pressure sensor 15 except during sampling, and an internal A / D that does not need to be driven when the pressure sensor 15 is not driven. A switching circuit 41 that prevents the drive current or drive voltage from being supplied also to the circuit section for conversion and the like is incorporated. The operation of the switching circuit 41 is controlled according to the input of the drive signal from the flow rate correction device 24.

  The temperature sensor I / F circuit 34 drives the temperature sensor 16 that detects the temperature of the fluid to be measured at the time of sampling, and A / D converts the detection signal of the temperature sensor 16 to obtain the temperature value of the fluid to be measured. Extract as a compatible digital signal.

  The temperature sensor I / F circuit 34 is also prevented from supplying a drive current or drive voltage to the temperature sensor 16 except during sampling, and an internal A / D that does not need to be driven when the temperature sensor 16 is not driven. A switching circuit 42 that prevents the drive current or drive voltage from being supplied also to the circuit section for conversion and the like is incorporated. The switching circuit 42 is controlled in response to the input of the drive signal from the flow rate correction device 24.

  On the other hand, the internal power supply circuit 35 is connected to the battery 21 and generates a drive current or a drive voltage for driving each unit, and the measurement arithmetic device 31, the flow rate detection sensor I / F circuit 32, the pressure sensor I / F circuit. 33, supplied to the temperature sensor I / F circuit 34, the input circuit 37, and the output circuit 38.

  The battery voltage monitoring circuit 36 is attached to the internal power supply circuit 35 and monitors whether or not the battery as the drive power supply has exceeded a certain usage capacity and has reached the end of its life. The battery voltage monitoring circuit 36 compares the battery voltage of the battery 21 with a preset specified voltage, and supplies a battery voltage drop signal to the measurement calculation device 31 when the battery voltage drops below the specified voltage. Note that the battery voltage monitoring circuit 36 can be substituted by the measurement operation device 31 that takes in and compares the battery voltage of the battery 21 subjected to A / D conversion as data.

  The input circuit 37 is connected to the measurement calculation device 31 and is connected to the sampling time setting unit 23 in the illustrated example. Thereby, the measurement calculation device 31 takes in the sampling interval of the temperature / pressure state of the fluid to be measured, which is adjusted and set by operating the operation unit with the sampling time setting unit 23, and uses it in the correction data acquisition / updating process.

  The output circuit 38 is connected to the measurement arithmetic unit 31 and is connected to the flow rate display 22 in the illustrated example, and outputs measurement information such as an instantaneous flow rate and an integrated flow rate of the fluid to be measured to the flow rate display 22. To do.

  Next, the flow rate correction calculation control process performed by the measurement calculation device 31 of the flow rate correction device 24 configured as described above will be described with reference to the drawings.

FIG. 4 is a flowchart of a flow rate correction process performed by the measurement calculation device of the flow rate correction device shown in FIG.
The measurement calculation device 31 is constantly supplied with its own drive current or drive voltage via the internal power supply circuit 35, and the actual temperature and pressure state of the fluid to be measured is reflected during the operation of the flow rate correction device 24. A flow rate correction process is performed as needed to correct the initially measured flow rate measured as it is to the measured flow rate in the reference state (the measured flow rate in the standard state) based on the reference temperature and the reference pressure.

  In the flow rate correction device 24 applied to the Roots flow meter 1 shown in FIG. 1, the flow rate detection unit including the magnet 13 and the magnetic sensor 14 of the flow rate measurement mechanism provided in the flow meter body 2 detects the flow rate. Since the flow rate pulse signal corresponding to the flow for each unit flow rate of the fluid to be measured is supplied as the flow rate measurement signal via the sensor I / F circuit 32, the measurement arithmetic unit 31 monitors the input state of the flow rate pulse signal. Every time the input of a flow rate pulse corresponding to the unit volume flow rate of the fluid to be measured is detected, the flow rate correction process shown in steps S10 to S40 is performed.

  In step S10 (hereinafter, the description of the step is omitted), the measurement calculation device 31 counts the flow rate pulse every time an input of the flow rate pulse is detected and converts it to an integer unit of measurement, thereby measuring the fluid to be measured. The initial measured flow rate is obtained while the actual temperature and pressure conditions are reflected. In this case, the initial measured flow rate corresponds to an instantaneous flow rate or an integrated flow rate that reflects the actual temperature and pressure state of the fluid to be measured.

  In S <b> 20, the measurement calculation device 31 reads out the pressure correction count that is separately calculated by the correction data acquisition update processing (sampling processing) performed in parallel and updated and stored in the storage unit in the device 31.

  In S <b> 30, the measurement calculation device 31 reads out the temperature correction count that is separately calculated by the correction data acquisition update processing (sampling processing) performed in parallel and similarly updated and stored in the storage unit in the device 31. .

  In S40, the measurement calculation device 31 uses the pressure measurement coefficient and the temperature correction count read out in S20 and S30 as the reference for the initially measured flow rate measured while reflecting the actual temperature and pressure state of the fluid to be measured. Correct to the measured flow rate in the standard state (measured flow rate in the standard state) by temperature and reference pressure. In this case, the measured flow rate in the reference state corresponds to the instantaneous flow rate or the integrated flow rate in the reference state based on the reference temperature and the reference pressure.

  In S <b> 50, the measurement calculation device 31 outputs the acquired measured flow rate in the reference state as data via the output circuit 38. In the case of the illustrated example, the measured flow rate in the reference state is supplied to the flow rate display 22 via the output circuit 38 and displayed.

  As described above, in the flow rate correction calculation control process performed during the operation of the flow rate correction device 24, the flow rate correction process for calculating the measured flow rate in the reference state based on the reference temperature and the reference pressure of the fluid to be measured is performed by the flow meter body 2. In order to deal with a flow rate measurement signal output from a flow rate detection unit of a flow rate measurement mechanism provided in the flow path 5, every time the initially measured flow rate is calculated and updated, specifically, in the case of the roots flow meter 1, a magnet Each time a flow rate pulse is supplied from a flow rate detection unit consisting of 13 and a magnetic sensor 14 via a flow rate detection sensor I / F circuit 32, the measurement calculation device 31 is always driven during flow rate measurement using a flow meter. , Done from time to time.

  In contrast to the flow rate correction process performed whenever the initial measured flow rate is calculated and updated, the correction data acquisition update process and the correction control process are performed in parallel with the flow rate correction process during the flow rate measurement using the flow meter. Periodically, it is performed by the measurement calculation device 31.

  FIG. 5 is a flowchart of correction data acquisition update processing and correction control processing performed by the measurement arithmetic device of the flow rate correction device shown in FIG.

  While the flow rate correction device 24 is in operation, the measurement arithmetic unit 31 that is constantly supplied with its own drive current or drive voltage via the internal power supply circuit 35 performs the flow rate correction process in parallel with the flow rate correction process described above. When it is detected that the correction data acquisition / update process of the correction data consisting of the pressure correction count and the temperature correction count used when correcting the initially measured flow rate to the reference measurement flow rate, and the battery 21 is approaching the end of its life, The correction control process for changing the correction data acquisition method in the correction data acquisition / update process is periodically performed at a predetermined sampling interval adjusted and set by the sampling time setting unit 23 as shown in FIG.

  In S110, the measurement calculation device 31 detects whether or not a predetermined sampling interval (for example, 2 minutes) has passed since the previous sampling and the next (current) sampling is performed as the correction data acquisition update processing. .

  In S120, the measurement calculation device 31 detects the pressure and temperature of the fluid to be measured flowing through the measurement flow path 5 of the flow meter body 2 when the sampling time is reached as the correction data acquisition / update process. The pressure sensor 15 and the temperature sensor 16 arranged at 5 are driven. The measurement calculation device 31 outputs sensor drive signals to the pressure sensor I / F circuit 33 and the temperature sensor I / F circuit 34 when driving the pressure sensor 15 and the temperature sensor 16.

  Each of the pressure sensor I / F circuit 33 and the temperature sensor I / F circuit 34 is supplied from the internal power supply circuit 35 by the switching circuits 41 and 42 while the corresponding drive signal is supplied from the measurement calculation device 31. The drive current or drive voltage is supplied to the pressure sensor 15 and the temperature sensor 16 for a limited time, and only during this time, the drive current flows through the pressure sensor 15 and the temperature sensor 16.

  Therefore, the measurement calculation device 31 maximizes the load as the flow rate correction device 24 with respect to the remaining amount of the battery 21 when the remaining amount of the battery 21 has not yet decreased when the sensor driving signal is output. As described above, the drive signal output to the pressure sensor I / F circuit 33 and the drive signal output to the temperature sensor I / F circuit 34 are synchronously output, and the drive current is simultaneously applied to each of the pressure sensor 15 and the temperature sensor 16. Make it flow.

  In S130, the measurement arithmetic unit 31 causes the battery 21 as the driving power source to be used from the battery voltage monitoring circuit 36 at a constant use by supplying the driving current to the pressure sensor 15 and the temperature sensor 16 simultaneously as the correction control process. It is confirmed whether or not a battery voltage drop signal that has detected that the battery life has reached its capacity is approached.

  In other words, the measurement calculation device 31 calculates the measured flow rate in the reference state based on the reference temperature and the reference pressure of the fluid to be measured shown in FIG. 4 by monitoring the supply of the battery voltage drop signal from the battery voltage monitoring circuit 36. At the moment when the battery 21 whose battery voltage is higher than the specified value when the flow rate correction process is performed drives each of the pressure sensor 15 and the temperature sensor 16 in the correction data acquisition and update process performed in parallel with the flow rate correction process. Then, it is confirmed whether or not the battery voltage is greatly reduced by the respective drive currents and falls below the specified value.

  Therefore, the measurement calculation device 31 drives the pressure sensor 15 and the temperature sensor 16 in the correction data acquisition / update process performed in parallel with the flow rate correction process without being supplied with the battery voltage drop signal from the battery voltage monitoring circuit 36. Even when the battery voltage of the battery 21 exceeds the specified value for the moment, even if the drive current flows through the pressure sensor 15 and the temperature sensor 16 simultaneously, the rated drive of the pressure sensor 15 and the temperature sensor 16 is guaranteed. I can confirm that.

  On the other hand, when the battery voltage drop signal is supplied from the battery voltage monitoring circuit 36 and the pressure sensor 15 and the temperature sensor 16 are driven in the correction data acquisition / update process performed in parallel with the flow rate correction process, the battery voltage of the battery 21 is When the measured value is lower than the specified value, the measurement calculation device 31 does not guarantee the rated drive of the pressure sensor 15 and the temperature sensor 16 when the drive current flows through the pressure sensor 15 and the temperature sensor 16 at the same time. It can be confirmed that there is a possibility that the measurement of the pressure and temperature may not be performed accurately.

  In S140, the measurement calculation device 31 assumes that the rated drive of the pressure sensor 15 and the temperature sensor 16 is guaranteed even if the drive current flows through the pressure sensor 15 and the temperature sensor 16 at the same time as the correction data acquisition update processing. Via the sensor I / F circuit 33 and the temperature sensor I / F circuit 34, the pressure and temperature of the fluid to be measured flowing through the measurement flow path 5 of the flow meter main body 2 are taken in.

  In S150, as the correction data acquisition / update process, the measurement arithmetic unit 31 completes the intake of the pressure and temperature of the fluid to be measured flowing through the measurement flow path 5 of the flow meter main body 2, and then the pressure sensor I / F circuit 33. In addition, the sensor drive signal output to each of the temperature sensor I / F circuit 34 is stopped so that the drive current does not flow through the pressure sensor 15 and the temperature sensor 16.

  In S160, the measurement calculation device 31 performs the initial measurement flow rate based on the change state of the actual temperature and pressure of the fluid to be measured acquired in S140 with respect to the reference state due to the reference temperature and the reference pressure as the correction data acquisition and update process. A correction coefficient (temperature, pressure correction coefficient) for correcting the measured flow rate in the reference state is calculated.

  In S170, the measurement calculation device 31 replaces the pressure correction count and temperature correction count used in the previous flow rate correction processing shown in FIG. The count and temperature correction count are updated and stored in the storage unit in the apparatus 31.

  Therefore, in the flow rate correction device 24, the measurement calculation device 31 performs the correction data acquisition / updating process shown in S110, S120, and S140 to S170 described above, so that the pressure sensor 15 and the temperature sensor 16 are driven synchronously to both simultaneously. A configuration in which a drive current flows, and based on the battery voltage of the battery when the maximum load current of the device is flowing, a configuration in which the battery 21 as the drive power supply exceeds a certain use capacity and has reached the end of its life. It has become.

  In addition, in the correction control process shown in S130, the measurement calculation device 31 detects that the battery 21 as the drive power source has reached a certain operating capacity and has reached the end of its life, and thereafter, as described above. Correction data of S200 to S280 in which the method for acquiring the pressure and temperature of the fluid to be measured flowing through the measurement flow path 5 of the flow meter main body 2 is changed with respect to the correction data acquisition and update process shown in S110, S120, and S140 to S170. Perform acquisition update processing.

  In S180, when the measurement calculation device 31 detects in the correction control process shown in S130 that the battery 21 has exceeded its fixed usage capacity and has reached the end of its life, A battery life signal is output via the output circuit 38. In the case of the illustrated example, the battery life signal is supplied to the flow rate indicator 22 via the output circuit 38, and an alarm is displayed on the flow rate indicator 22. Further, for example, if the flow rate correction device 24 is connected to a transfer management system located in an office remote from the transfer site of the fluid to be measured, the battery life signal is transmitted via the output circuit 38 as data. It can be supplied to the transmitter and reported to the office.

  In S190, the measurement calculation device 31 performs the correction process for acquiring and updating the battery voltage in S110, S120, S140 to S170, and the pressure sensor I / F circuit 33 and the temperature sensor I / F in S120. The sensor drive signal output to each of the circuits 34 is stopped so that the drive current does not flow through the pressure sensor 15 and the temperature sensor 16 once.

  Then, the measurement calculation device 31 performs the correction data acquisition update process shown in S200 to S280 instead of the correction data acquisition update process shown in S110, S120, and S140 to S170.

  In S200, the measurement calculation device 31 first detects the temperature of the fluid to be measured flowing through the measurement flow path 5 of the flow meter body 2 as the correction data acquisition / update process. Of the sensors 16, only the temperature sensor 16 is driven.

  Accordingly, the measurement calculation device 31 outputs a sensor drive signal to the temperature sensor I / F circuit 34, but does not output a sensor drive signal to the pressure sensor I / F circuit 33. As a result, in the flow rate correction device 24, the measurement calculation device 31 performs the correction data acquisition / updating process shown in S110, S120, and S140 to S170 described above, and the pressure sensor 15 and the temperature sensor 16 are driven synchronously to drive both simultaneously. The load current supplied from the battery 21 to the flow rate correction device 24 is smaller than the case where the maximum load current is flowing from the battery 21 to the flow rate correction device 24 so that the current flows. Is suppressed.

  In S210, when the decrease in the battery voltage of the battery 21 is suppressed in this way, the rated drive of one of the pressure sensor 15 and the temperature sensor 16 is guaranteed even if the drive current flows through only one of the pressure sensor 15 and the temperature sensor 16. As a result, the measurement calculation device 31 takes in the temperature of the fluid to be measured detected by the temperature sensor 16 being driven via the temperature sensor I / F circuit 34 as the correction data acquisition update processing.

  In S <b> 220, the measurement arithmetic unit 31 outputs to the temperature sensor I / F circuit 34 when the intake of the temperature of the fluid to be measured flowing through the measurement flow path 5 of the flow meter body 2 is completed as the correction data acquisition / update process. The sensor drive signal that has been stopped is stopped so that the drive current does not flow through the pressure sensor 15 and the temperature sensor 16 once.

  In S230, the measurement arithmetic unit 31 detects the pressure of the fluid to be measured flowing through the measurement flow path 5 of the flow meter body 2 as the correction data acquisition / update process, so that the pressure sensor 15 disposed in the measurement flow path 5 and Of the temperature sensor 16, only the pressure sensor 15 is driven.

  Accordingly, the measurement calculation device 31 outputs a sensor drive signal to the pressure sensor I / F circuit 33, but does not output a sensor drive signal to the temperature sensor I / F circuit 34. As a result, in the flow rate correction device 24, the measurement calculation device 31 performs the correction data acquisition / updating process shown in S110, S120, and S140 to S170 described above, and the pressure sensor 15 and the temperature sensor 16 are driven synchronously to drive both simultaneously. The load current supplied from the battery 21 to the flow rate correction device 24 is smaller than the case where the maximum load current is flowing from the battery 21 to the flow rate correction device 24 so that the current flows. Is suppressed.

  In S240, when the decrease in the battery voltage of the battery 21 is suppressed in this manner, the rated drive of one of the pressure sensor 15 and the temperature sensor 16 is guaranteed even if the drive current flows through only one of the pressure sensor 15 and the temperature sensor 16. Therefore, the measurement calculation device 31 takes in the pressure of the fluid to be measured detected by the driving pressure sensor 15 via the pressure sensor I / F circuit 33 as the correction data acquisition update processing.

  In S250, the measurement arithmetic unit 31 outputs the pressure sensor I / F circuit 33 to the pressure sensor I / F circuit 33 when the intake of the pressure of the fluid to be measured flowing through the measurement flow path 5 of the flow meter body 2 is completed as the correction data acquisition and update process. The sensor drive signal that has been stopped is stopped so that the drive current does not flow through the pressure sensor 15 and the temperature sensor 16 once.

  In S260, as the correction data acquisition / update process, the measurement calculation device 31 does not cause the drive current to flow through the pressure sensor 15 and the temperature sensor 16 at the same time, and acquires the actual temperature and pressure of the measured fluid acquired in S210 and S240. Based on the change state with respect to the reference state due to the reference temperature and the reference pressure, a correction coefficient (temperature correction coefficient, pressure correction coefficient) for correcting the initial measurement flow rate to the measurement flow rate in the reference state is calculated.

  In S270, the measurement calculation device 31 replaces the pressure correction count and the temperature correction count newly used in the flow rate correction processing shown in FIG. 4 with the newly calculated pressure correction count and temperature correction count. The data is updated and stored in the storage unit 31.

  In S280, the measurement calculation device 31 detects whether or not a predetermined sampling interval (for example, 2 minutes) has passed and the next sampling has been performed as the correction data acquisition update processing.

  Then, each time the sampling time is detected, the measurement calculation device 31 shows the steps S200 to S280 while suppressing the load current supplied from the battery 21 to the flow rate correction device 24 with respect to the maximum load current. Perform correction data acquisition update processing.

  Next, the operation and effect of the flow rate correction device 24 according to the present embodiment configured as described above will be described with reference to FIG.

FIG. 6 is a diagram showing temporal changes in power consumption and battery voltage in the flow rate correction apparatus.
In the flow rate correction device 24, the flow rate correction process shown in FIG. 4 is performed whenever the initial measured flow rate is calculated and updated. In this state, the flow rate correction process can be performed.

  On the other hand, the correction data acquisition and update process shown in FIG. 5 performed in parallel with the flow rate correction process during the flow measurement of the fluid to be measured by the flow meter is periodically performed at a predetermined sampling interval. Even during the measurement of the flow rate of the fluid to be measured, the measurement calculation device 31 does not need to be in a state in which the correction data acquisition / update process can be steadily performed after the end of the process until the next sampling. .

  Therefore, in the flow rate correction device 24, as shown in the temporal transition of the power consumption W in FIGS. 6A and 6B, the flow rate correction device 24 including the measurement calculation device 31 performs flow rate correction processing. The power consumption wb per unit time consumed in is constant and is constantly consumed regardless of the change in the elapsed time t.

  On the other hand, the power consumption per unit time consumed when the flow rate correction device 24 including the measurement calculation device 31 performs the correction data acquisition / updating process is consumed not in a steady state but in a spot manner.

  Therefore, the increase wc of power consumption per unit time consumed when the flow rate correction device 24 including the measurement calculation device 31 performs the correction data acquisition update process in parallel with the flow rate correction processing is the same as that of the measurement calculation device 31. Since the driving state is constantly performed in order to perform the correction process, mainly the power consumption P for driving the pressure sensor 15 to detect the pressure of the fluid to be measured and the temperature of the fluid to be measured are detected. Therefore, it is roughly divided into a power consumption T for driving the temperature sensor 16.

  When the maximum power consumption in the flow rate correction device 24 is performed, the flow rate correction process is performed as needed, and the correction data acquisition update process is periodically performed at a predetermined sampling interval, so that the correction data acquisition update process is performed. This can be regarded as sampling.

  On the other hand, in the flow rate correction device 24, the specified voltage vth for detecting that the battery 21 as the driving power source has exceeded a certain usage capacity and has reached the end of its life and the remaining amount of the battery 21 has decreased below a predetermined amount. Is set, and the measurement calculation device 31 is configured to detect that the battery voltage of the battery 21 has fallen below the specified voltage vth.

  Therefore, in detecting that the battery voltage of the battery 21 is lower than the specified voltage vth, in view of the above-described power consumption characteristics in the flow rate correction device 24, as shown in FIG. The measurement operation device 31 performs the correction data acquisition / updating process and the correction control process, thereby providing the following operations and effects.

  First, as shown in FIGS. 6A and 6B, the maximum power consumption “wb + wc” of the flow rate correction device 24 is “wb + P + T”, and the voltage drop of the battery voltage of the battery 21 during sampling is maximized. Therefore, the correction data acquisition / updating process as shown in S110, S120, and S140 to S170 is performed so that the pressure sensor 15 and the temperature sensor 16 are driven synchronously so that the drive current flows through them simultaneously.

  As shown in the section X in FIGS. 6A and 6B, the battery voltage of the battery 21 has not decreased, and the internal resistance of the battery 21 has not increased yet. If sufficient, the decrease in the battery voltage of the battery 21 is small even during sampling in which correction data acquisition / update processing as shown in S110, S120, and S140 to S170 is performed.

  However, when used for a long time, when the battery voltage of the battery 21 decreases, the internal resistance of the battery 21 increases, and the remaining amount of the battery 21 decreases, as shown in S110, S120, S140 to S170. As shown in the section Y in FIGS. 6A and 6B, the decrease in the battery voltage of the battery 21 at the time of sampling during which the correction data acquisition / updating process is performed increases its drop value.

  Thus, initially, the maximum power consumption “wb + wc” of the flow rate correction device 24 is “wb + P + T”, and the pressure sensor 15 and the temperature sensor 16 are synchronized so as to maximize the voltage drop of the battery voltage during sampling. When the drive current flows through both of them simultaneously, the correction data acquisition / update process is performed in parallel when detecting that the remaining amount of the battery 21 has decreased below a predetermined amount by comparison with the specified voltage vth. Thus, it is possible to detect a decrease in the remaining amount of the battery 21 with a margin in the voltage of the battery 21 in a state where only the flow rate correction processing is performed.

  As a result, in setting the specified voltage vth for detecting that the remaining amount of the battery 21 has dropped below a predetermined amount, it is not necessary to set the specified voltage vth with an uncertain and sufficient margin. It is possible to efficiently consume the battery 21 as a drive source.

  Further, when the measurement calculation device 31 detects that the voltage of the battery 21 has fallen below the specified voltage vth by the correction control processing as shown in S130, S180, and S190 of FIG. 5, the processing by the correction data acquisition update processing The content is changed from the processing content shown in S110, S120, and S140 to S170 to the processing content shown in S200 to S280, and the pressure sensor 15 and the temperature sensor 16 are not driven synchronously. The correction data (temperature correction coefficient, pressure correction coefficient) is acquired and updated without passing the drive current.

  Thereby, even after detecting that the remaining amount of the battery 21 has decreased below the predetermined amount, as shown in the comparison of the section Y between FIG. 6A and FIG. By suppressing the increase wc in power consumption per unit time consumed when the flow rate correction device 24 including the measurement arithmetic unit 31 performs the correction data acquisition update process in parallel with the flow rate correction process at the time of maximum power consumption. The correction data acquisition / update process can be continued.

  As a result, it is possible to efficiently draw out the remaining amount of the battery 21 as a drive source, and to further increase the efficient consumption of the battery 21, thereby extending the period during which accurate flow rate management of the fluid to be measured can be performed. it can.

  Next, a modification of the correction data acquisition / update process and the correction control process performed by the measurement arithmetic unit of the flow rate correction apparatus shown in FIG. 5 will be described with reference to FIG.

FIG. 7 is a flowchart of a modification of the correction data acquisition / update process and the correction control process shown in FIG.
7 differs from the correction data acquisition / update process and the correction control process shown in FIG. 5 in the content of the correction control processing part, and the correction data acquisition / update process part is the same. Therefore, in FIG. 7, the same individual processing content portion (step S) as that in FIG. 5 is given the same reference numeral and description thereof is omitted, and only the characteristic portion including the correction control processing portion will be described.

  In the embodiment shown in FIG. 5, it is detected whether or not a battery voltage drop signal is supplied from the battery voltage monitoring circuit 36 to detect that the battery 21 as a driving power source has exceeded a certain usage capacity and has reached the end of its life ( S130), that is, the battery voltage monitoring circuit 36 compares the battery voltage of the battery 21 with a predetermined voltage set in advance, and determines whether or not the battery voltage is lower than the predetermined voltage.

  In the embodiment shown in FIG. 7, the detection that the battery 21 as the drive power source has reached a certain usage capacity and has reached the end of its life is sampled by the correction data acquisition and update process shown in S110, S120, and S140 to S170. At time (S110), in order to detect the pressure and temperature of the fluid to be measured flowing through the measurement flow path 5 of the flowmeter body 2, the pressure sensor 15 and the temperature sensor 16 disposed in the measurement flow path 5 are driven (S120). ) The detection is based on the magnitude of the voltage drop of the battery 21 at the time. For this reason, the flow rate correction device 24 shown in FIG. 3 has a configuration in which the measurement calculation device 31 can take in the battery voltage of the A / D converted battery 21 instead of the battery voltage monitoring circuit 36.

  In FIG. 7, in S111, when the measurement arithmetic unit 31 detects that the sampling time is reached (S110), as the correction data acquisition / update process, the pressure of the fluid to be measured flowing through the measurement flow path 5 of the flow meter body 2 and Before driving the pressure sensor 15 and the temperature sensor 16 arranged in the measurement flow path 5 to detect the temperature (S120), as a correction control process, when the drive current does not flow through the pressure sensor 15 and the temperature sensor 16 The battery voltage V1 of the battery 21 is read.

  In S122, the measurement calculation device 31 drives the pressure sensor 15 and the temperature sensor 16 as a correction control process (S120), and the battery voltage of the battery 21 decreased due to the drive current flowing through the pressure sensor 15 and the temperature sensor 16, respectively. Read V2.

  In S123, the measurement calculation device 31 drives the pressure sensor 15 and the temperature sensor 16 from the battery voltages V1 and V2 of the battery 21 before and after the drive current flows through the pressure sensor 15 and the temperature sensor 16, respectively, as correction control processing. The battery voltage drop ΔV (= V1−V2) of the battery 21 is calculated.

  In S131, the measurement calculation device 31 sets a predetermined voltage drop value in which a battery voltage drop ΔV (= V1−V2) of the battery 21 when the pressure sensor 15 and the temperature sensor 16 are driven is set as a correction control process. Compared with the above, based on whether or not the battery voltage drop ΔV of the battery 21 exceeds a predetermined voltage drop value, it is determined whether or not the battery 21 as the driving power source has exceeded a certain usage capacity and has reached the end of its life. To detect.

  That is, in the correction control process shown in S111, S122, S123, S131, S180, and S190 in FIG. B) Relationship between the remaining amount of the battery 21 and the decrease in the battery voltage of the battery 21 at the time of executing the correction data acquisition / update process shown in S110, S120, S140 to S170, which is described separately in the sections X and Y in FIG. Is used. Specifically, as shown in a section X in FIGS. 6A and 6B, the battery voltage of the battery 21 has not decreased, and the internal resistance of the battery 21 has not yet increased. If the remaining capacity of the battery 21 is sufficient, the battery voltage drop of the battery 21 is small even during sampling when the correction data acquisition / updating process as shown in S110, S120, and S140 to S170 is performed. When the battery voltage of the battery 21 decreases, the internal resistance of the battery 21 increases, and the remaining amount of the battery 21 decreases, the correction data acquisition update process shown in S110, S120, S140 to S170 is performed. The decrease in the battery voltage of the battery 21 at the time of sampling is based on the increase in the drop value as shown in the section Y in FIGS. 6 (A) and 6 (B). In other words, in the battery life determination process shown in S111, S122, S123, and S131, the battery when the correction data acquisition and update process is performed as the internal resistance of the battery 21 increases and the remaining battery level decreases. This is based on the fact that the battery voltage drop ΔV (= V1−V2) is increased.

  In FIG. 7, along with the detection at the next sampling shown in S280 of the correction data acquisition / update process shown in S200 to S280, in S279, the measurement arithmetic unit 31 performs a reset operation as a correction control process. The presence or absence, that is, whether or not the battery 21 has been replaced is confirmed.

  Thereby, when the reset operation is performed, that is, when the battery 21 is replaced, the measurement calculation device 31 determines that the capacity of the battery 21 as the driving power source has been restored by the battery replacement, and suppresses power consumption. The correction data acquisition / update process shown in S200 to S280 is changed to the correction data acquisition / update process shown in S110, S120, and S140 to S170 for efficient consumption of the battery 21.

  The reset operation here means a reset switch operation (not shown) accompanying the replacement of the battery 21, a reset signal input from the outside via the input circuit 37, and a battery in a power-on reset of the measurement arithmetic device 31. Voltage restoration confirmation, etc. are included.

  The flow rate correction apparatus according to the embodiment of the present invention is as described above, but the embodiment is not limited to the above-described configuration, and various modifications can be made to the specific mode.

  For example, in the above-described embodiment, the case where the flow rate correction device 24 is applied to the roots flow meter 1 has been described. However, the configuration in which the measurement calculation device 31 in the flow rate correction device 24 acquires the initial measurement flow rate is the flow rate correction device 24. Is appropriately changed according to the difference between the flow rate measurement mechanism provided in the flowmeter main body 1 to which is applied and the flow rate measurement signal output from the flow rate measurement mechanism.

1 Roots flow meter, 2 Flow meter body, 3 Measuring unit housing, 4 Casing,
5 Measurement channel, 6 Weighing chamber, 7a, 7b Eyebrows rotor, 8a, 8b Rotating shaft,
9 Bearing, 10 Seal mechanism, 11 Side lid, 12a, 12b Timing gear,
13 magnet, 14 magnetic sensor, 15 pressure sensor, 16 temperature sensor,
21 battery, 22 flow rate indicator, 23 sampling time setter,
24 flow rate correction device, 31 measurement calculation device, 32 flow rate detection sensor I / F circuit,
33 Pressure sensor I / F circuit, 34 Temperature sensor I / F circuit,
35 internal power supply circuit, 36 battery voltage monitoring circuit, 37 input circuit,
38 output circuit, 41, 42 switching circuit

Claims (2)

A temperature sensor that outputs a detection signal corresponding to the temperature value of the fluid to be measured by supplying a drive voltage or a drive current; and
A pressure sensor that outputs a detection signal corresponding to the pressure value of the fluid to be measured by supplying a driving voltage or a driving current;
A sensor drive unit for supplying / cutting a drive voltage or a drive current to each of the temperature sensor and the pressure sensor;
The driving / controlling of the driving voltage or driving current by the sensor driving unit is controlled to control the driving of the temperature sensor and the pressure sensor, respectively, and the driving voltage or driving current is supplied from the temperature sensor / pressure sensor being supplied. Based on the detected temperature and detected pressure of the fluid to be measured acquired by taking in the output detection signal, the initial measured flow rate measured according to the actual temperature and pressure state of the fluid to be measured is based on the reference temperature and the reference pressure. A flow rate correction calculation unit for correcting the measured flow rate in the reference state;
A battery for supplying a driving voltage or a driving current to each of the temperature sensor and the pressure sensor via the flow rate correction calculation unit and the sensor driving unit;
A battery life determination unit that takes in the battery voltage of the battery, detects that the battery voltage is equal to or lower than a predetermined voltage, and outputs a signal indicating that the battery life is approaching;
In order to drive the temperature sensor and the pressure sensor synchronously, the flow rate correction calculation unit controls the sensor driving unit, and the terminal voltage of the battery when the temperature sensor and the pressure sensor are driven synchronously is determined. A correction control unit to be taken into the battery life determination unit ,
When the battery life determination unit detects that the battery voltage has become equal to or lower than a predetermined voltage, the correction control unit causes the flow rate correction calculation unit to cause the sensor to drive the temperature sensor and the pressure sensor asynchronously. A flow rate correction apparatus , wherein a drive unit is controlled, and the terminal voltage of the battery when the temperature sensor and the pressure sensor are driven asynchronously is taken into the battery life determination unit . The correction control unit
In order to drive the temperature sensor / pressure sensor asynchronously, the flow rate correction calculation unit controls the sensor driving unit, and the terminal voltage of the battery when the temperature sensor / pressure sensor is driven asynchronously is determined as the battery life. When a reset operation is input in a control state to be taken into the determination unit, the flow rate correction calculation unit is controlled by the flow rate correction calculation unit to drive the temperature sensor / pressure sensor synchronously, and the temperature sensor / The flow rate correction device according to claim 1, wherein the flow rate correction device returns to a control state in which the terminal voltage of the battery when the pressure sensor is driven synchronously is taken into the battery life determination unit .

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