JP5427395B2 - Flowmeter - Google Patents

Description

  Some embodiments according to the present invention relate to a flow meter for detecting a fluid to be measured such as gas or liquid.

  Conventionally, using this type of flow meter, the amount of fluid used in which time zone, the amount of flow in which time zone, etc. There is a request to know the usage status of

To solve this problem, the use of multiple faucet fluids using a flow meter along with the date and time of use for the purpose of collecting information on the instantaneous flow rate at a given time (hereinafter sometimes referred to as “trend data”) There is known a data processing system that detects the amount and analyzes information on the detected fluid usage using a personal computer or the like (see, for example, Patent Document 1).
JP 2005-147721 A

  However, in a data processing system such as that described in Patent Document 1, a device configuration for collecting trend data and analyzing usage conditions becomes complicated, and high cost is required to construct such a system. There was a problem.

  In addition, even when a watch is mounted on the flow meter to collect trend data, the watch is prone to failure and error (clock error) with long-term use, and power consumption is relatively large. And since it is comparatively expensive, there is a high possibility that problems to be improved still remain in terms of measurement accuracy and cost. A so-called radio clock is mounted and the time can be periodically corrected using a time signal from a public radio broadcast, but the cost increases.

  Some aspects of the present invention have been made in view of the above-described problems, and provide a flow meter that can grasp the use state of a fluid to be measured while having a relatively inexpensive and simple configuration. Is one of the purposes.

  The flowmeter according to the present invention includes a flow rate detection means for detecting a flow rate of a fluid to be measured flowing through a predetermined flow path, a detection period setting means for setting the start and end of a detection period, and the flow rate detection means during the detection period. Flow rate information acquisition means for acquiring flow rate information that is information related to the flow rate in the detection period based on the detected flow rate.

  According to such a configuration, the start and end of the detection period are set, and the flow rate information is acquired based on the flow rate detected by the flow rate detection means during the detection period. Here, in order to grasp the usage state of the fluid to be measured, the information on the time itself is not necessarily required. If a predetermined period is set and the flow rate of the fluid to be measured is detected over the period, for example, the period Flow rate information such as the maximum, minimum, and average flow rates can be acquired, so the amount of flow used in which time zone and the amount of flow in which time zone are covered. It is possible to grasp the usage status of the measurement fluid. Therefore, it is possible to grasp the usage state of the fluid to be measured from the flow rate information acquired based on the flow rate detected in the detection period without collecting trend data that requires time information.

  Further, in the flow meter, the flow rate detecting means detects an instantaneous flow rate of the fluid to be measured, and the flow rate information includes a maximum value, a minimum value, and an average value of the instantaneous flow rate in the detection period. It can be configured to include at least one.

  According to such a configuration, since the flow rate information includes at least one of the maximum value, the minimum value, and the average value of the instantaneous flow rate in the detection period, the maximum value, the minimum value, and the average value of the instantaneous flow rate in the detection period. At least one piece of information can be acquired.

  The flow meter may further include display means for displaying the flow rate information.

  According to such a configuration, since the flow rate information is displayed on the display unit, the flow rate information can be notified to the user.

  In the flow meter, the flow rate information includes at least two of a maximum value, a minimum value, and an average value of instantaneous flow rates in the detection period, and the display unit includes a plurality of pieces of information included in the flow rate information. Can be configured to display in a predetermined order.

  According to such a configuration, since a plurality of pieces of information included in the flow rate information are displayed on the display unit in a predetermined order, at least two pieces of information among the maximum value, the minimum value, and the average value of the instantaneous flow rate in the detection period are stored in the user Can be automatically displayed in a predetermined order without setting the order.

  In the flow meter, the flow rate information includes at least two of a maximum value, a minimum value, and an average value of the instantaneous flow rate in the detection period, and designates one of a plurality of pieces of information included in the flow rate information. Designating means, and the display means can be configured to display information designated by the designation means.

  According to such a configuration, the information designated by the designation unit among the plurality of pieces of information included in the flow rate information is displayed on the display unit. Therefore, the maximum value, the minimum value, and the average value of the instantaneous flow rate in the detection period can be determined from the user. It is possible to display one piece of information arbitrarily designated by.

  Further, in the flow meter, the display means may be configured to display when the end of the detection period is set by the detection period setting means.

  According to such a configuration, when the end of the detection period is set, it is displayed on the display means. Therefore, at least one information among the maximum value, the minimum value, and the average value of the instantaneous flow rate in the detection period is displayed by the user's operation. Can be displayed automatically without the need for.

  The flow meter further includes display activation means for activating the display means, and the display means is activated by the display activation means after the end of the detection period is set by the detection period setting means. Can be configured to be displayed.

  According to such a configuration, since the end of the detection period is set and then displayed on the display means when activated by the display activation means, at least among the maximum value, the minimum value, and the average value of the instantaneous flow rate in the detection period One piece of information can be displayed at an arbitrary timing by a user operation.

  According to the present invention, it is possible to grasp the usage state of the fluid to be measured from the flow rate information acquired based on the flow rate detected in the detection period without collecting trend data that requires time information. This eliminates the need for a clock to obtain time information, and eliminates the need for equipment configuration and costs for collecting and analyzing trend data, so it has a relatively inexpensive and simple configuration, while being measured. It is possible to grasp the usage status of the fluid.

  Hereinafter, an embodiment of a flow meter according to the present invention will be described with reference to the drawings. The flow meter in this embodiment is an integrated flow meter that detects the instantaneous flow rate of a gas that is a fluid to be measured, for example, and calculates the amount of gas used by integrating the detected instantaneous flow rate.

  As shown in FIGS. 1 to 4, the flow meter 1 is connected to a flow meter body portion 2 that is attached to a part of a pipe P through which gas flows and forms a flow path, and is connected to the flow meter body portion 2. The measuring unit 3 including the sensor 12 and the control unit 30 is provided as a main configuration.

  As shown in FIGS. 2 to 4, the flow meter body portion 2 is a casing having a substantially rectangular parallelepiped shape, and is a pipe 7 having a circular cross section through which gas flows, and a throttle mechanism 8 formed in the middle of the pipe 7. The flow path is formed on the upper side of the pipe line 7 (the side to which the measuring unit 3 is connected), and is formed at positions upstream and downstream with the throttle mechanism 8 interposed therebetween. It has the branch flow paths 9 and 10 etc. which are connected. A pipe P is screwed and connected to the upstream side and the downstream side of the pipe line 7. The throttle mechanism 8 has an inner diameter that is smaller than the inner diameter of the pipe line 7 and generates a differential pressure before and after the throttle mechanism 8 in the gas flowing from the upstream pipe P to the downstream pipe P. Function.

  As shown in FIGS. 2 and 4, a concave portion 2 a having a substantially circular shape in plan view and having a predetermined depth is formed on the upper surface of the flow meter body portion 2, and the bypass flow of the measuring portion 3 is formed in the concave portion 2 a. A path forming portion 3b (described later) is fitted. The branch flow path 9 arranged on the upstream side of the throttle mechanism 8 is composed of a small diameter portion inside the flow meter body portion 2 and a large diameter portion outside the flow meter body portion 2. The bypass passage 3c is connected to a bypass passage 3c (described later) of the bypass passage forming portion 3b. Similarly, the branch flow path 10 arranged on the downstream side of the throttle mechanism 8 is also composed of a small diameter part inside the flow meter body part 2 and a large diameter part outside the flow meter body part 2, and the bypass flow path 3c. It is connected in communication.

  As shown in FIGS. 1 to 4, the measuring unit 3 has a housing having a substantially rectangular parallelepiped shape, and the display unit 4 a and the upper side of the housing (the side opposite to the flow meter body unit 2) are provided. A display operation panel 4 having an operation unit 4b is provided. As shown in FIG. 7, the display unit 4a shows a 7-segment display 41 that displays various types of information in a maximum of 5 digits or letters, and a mode set by the operation of the operation unit 4b. And a mode indicator composed of an instantaneous flow rate mode indicator 43. The 7-segment display 41 displays the detected instantaneous flow rate (L / min) of the detected gas and the integrated value (L) of the instantaneous flow rate in real time, and instantaneously in the detection period in which the start and end are set by the operation of the operation unit 4b. Information such as the maximum value, minimum value, and average value of the flow rate (hereinafter referred to as flow rate information during the detection period) is displayed. The operation unit 4b includes a left shift key 51 and a right shift key 52 for designating various information, a down key 53 and an up key 54 for setting a mode, and an execution key 55 for setting the start and end of a detection period. And an input key 56 and a display key 57 for activating the 7-segment display 41 and displaying information relating to the flow rate in the detection period (hereinafter also referred to as “flow rate information”).

  As shown in FIGS. 1 to 4, a cable connecting portion 5 for connecting a power feeding cable and a cable C for various signal transmission / reception is provided on the side surface of the housing constituting the measuring portion 3. In addition, a plate-like portion 3a is fixed to the lower side of the casing constituting the measuring unit 3 (the side to which the flow meter body unit 2 is connected). As shown in FIGS. 2 and 4, the screw 6 is screwed into the plate-like part 3 a of the measuring part 3 and the screw holes formed in the flow meter body part 2 and overlapped with each other. Is fixed to the flow meter body 2.

  As shown in FIG. 4, a bypass flow path forming part 3 b is arranged between the plate-like part 3 a of the measuring part 3 and the flow meter body part 2. The bypass flow path forming portion 3b is a thin member having a substantially circular shape in a plan view so as to be fitted into the concave portion 2a of the flow meter body portion 2. On the lower surface thereof, the bypass flow passages 9, 10 are provided. A bypass flow path 3c is formed in communication with each other. A part of the gas flowing through the pipe line 7 on the upstream side of the flow meter body part 2 is partially bypassed by the differential pressure across the throttle mechanism 8 via the upstream branch flow path 9 and the bypass flow path 3c of the measuring unit 3. And then bypassed to the downstream pipe line 7 via the branch flow path 10 on the downstream side of the flow meter body 2. The ratio (diversion ratio) between the flow rate that flows through the pipe 7 that is the main flow path and the flow rate that flows through the bypass flow path 3c needs to be specified in advance by calculation or measurement. A packing 11 as shown in FIGS. 2 and 4 is fitted in the recess 2a of the flow meter body 2 and around the bypass flow path forming portion 3b. The airtightness of the space formed by the shape portion 3a and the concave portion 2a of the flow meter body portion 2 is ensured.

  A flow sensor 12 is provided at the center of the plate-like part 3 a fixed to the bottom surface of the measuring part 3. The flow sensor 12 detects the flow velocity or flow rate (instantaneous flow rate) of the gas flowing through the bypass flow path 3c. Various configurations can be adopted as the flow sensor 12, and in the present embodiment, a thermal flow sensor having a diaphragm is adopted.

  As shown in FIGS. 5 and 6, the flow sensor 12 includes a substrate 20 provided with a cavity 26, an insulating film 25 disposed on the substrate 20 so as to cover the cavity 26, and a heater 21 provided on the insulating film 25. , Upstream temperature sensing resistor 22 provided upstream from heater 21, downstream temperature sensing resistor 23 provided downstream from heater 21, and surrounding provided upstream from upstream temperature sensing resistor 22 A temperature sensor 24 and the like are included.

  A portion of the insulating film 25 covering the cavity 26 constitutes a diaphragm having a small heat capacity and a heat insulating property with respect to the substrate 20. The ambient temperature sensor 24 measures the temperature of the fluid flowing into the bypass flow path 3c. The heater 21 is disposed at the center of the insulating film 25 covering the cavity 26, and is heated so as to be higher than the temperature of the fluid measured by the ambient temperature sensor 24, for example, 10 ° C. The upstream resistance temperature sensor 22 is used to detect the temperature upstream of the heater 21, and the downstream temperature resistance element 23 is used to detect the temperature downstream of the heater 21.

  Here, when the fluid in the bypass passage 3c is stationary, the heat applied by the heater 21 is diffused symmetrically in the upstream direction and the downstream direction. Accordingly, the temperatures of the upstream resistance temperature element 22 and the downstream resistance temperature element 23 are equal, and the electrical resistances of the upstream resistance temperature element 22 and the downstream resistance temperature element 23 are equal. On the other hand, when the fluid in the bypass channel 3c flows from the upstream to the downstream, the heat applied by the heater 21 is carried in the downstream direction. Therefore, the temperature of the downstream temperature measuring resistance element 23 becomes higher than the temperature of the upstream temperature measuring resistance element 22. Therefore, a difference is generated between the electrical resistance of the upstream resistance temperature sensor 22 and the electrical resistance of the downstream resistance temperature sensor 23. The difference between the electrical resistance of the downstream resistance temperature sensor 23 and the electrical resistance of the upstream resistance temperature sensor 22 has a correlation with the speed and flow rate of the fluid in the bypass passage 3c. Therefore, the speed and flow rate of the fluid flowing through the bypass flow path 3c are calculated from the difference between the electrical resistance of the downstream temperature measurement resistance element 23 and the electrical resistance of the upstream temperature measurement resistance element 22. The instantaneous flow rate (L / min) is calculated by multiplying the velocity of the fluid flowing through the bypass flow path 3c by the cross-sectional area of the bypass flow path 3c, and further, the flow rate of the pipe 7 that is the main flow path is calculated based on the diversion ratio. An instantaneous flow rate (L / min) is calculated.

As a material of the substrate 20 shown in FIGS. 5 and 6, silicon (Si) or the like can be used. As a material of the insulating film 25, silicon oxide (SiO ₂ ) or the like can be used. The cavity 26 is formed by anisotropic etching or the like. Further, platinum (Pt) or the like can be used for each material of the heater 21, the upstream resistance temperature sensor 22, the downstream resistance temperature sensor 23, and the ambient temperature sensor 24, and can be formed by lithography or the like.

  As shown in FIG. 7, the measurement unit 3 includes a control unit 30 that integrally controls various electronic devices. The control unit 30 is removable from a central processing unit (hereinafter referred to as “CPU”) 31, a ROM 32 in which various control programs are written in addition to algorithms for setting operations and arithmetic processing, and the flow meter 1. The EEPROM 33 to be mounted, the RAM 34 for storing information on the instantaneous flow rate detected by the flow sensor 12, the input / output interface 35 for inputting / outputting control signals and the like to / from the outside of the flow meter 1, and the outside of the flow meter 1 A communication unit 36 that transmits and receives information between them, a timer 37 that measures an elapsed time from the start to the end of the detection period, and the like. The RAM 34 stores information related to the elapsed time measured by the timer 37 in addition to information related to the instantaneous flow rate. The RAM 34 can also store flow rate information. Like the RAM 34, the EEPROM 33 can store information on the instantaneous flow rate detected by the flow sensor 12, information on elapsed time measured by the timer 37, and flow rate information. The information stored in the EEPROM 33 can be stored by an external device. Can be read.

  The CPU 31 reads various control programs in the ROM 32 and performs various information processing and device control. Specifically, when the user presses the execution key 55 of the operation unit 4b in a state where the start of the detection period is not set, the start of the detection period is set, and the CPU 31 activates the timer 37 to operate by the user. The measurement of the elapsed time from the input time is started, and the instantaneous flow rate of the gas detected by the flow sensor 12 is stored in the RAM 34. When the user presses the execution key 55 of the operation unit 4b again in the state where the start of the detection period is set, the end of the detection period is set, and the CPU 31 stops the timer 37 and ends the elapsed time measurement. At the same time, the measured elapsed time is stored in the RAM 34.

From the start to the end of the detection period, as shown in FIG. 8, the CPU 31 detects the instantaneous gas flow rates (Q ₁ , Q ₂ ,..., Q _N−1 ,. Q _N ) is detected. The detection interval (sampling period) of the instantaneous flow rate in the flow sensor 12 can be set as appropriate according to the specifications of the flow meter 1 and the usage situation. For example, as shown in FIG. 9, the detection interval in the flow sensor 12 is 10 minutes (sampling period: 10 minutes), and the detection can be set to be detected 20 times from the start to the end of the detection period. The CPU 31 converts the detected value (the instantaneous flow rate of the gas flowing through the bypass flow path 3c) in the flow sensor 12 into the instantaneous flow rate of the gas flowing through the pipe P using a predetermined conversion formula. Is stored in the RAM 34.

  Further, when the instantaneous flow rate mode is set by operating the lower key 53 or the upper key 54 of the operation unit 4b, as shown in FIG. 10 (A), the CPU 31 displays the instantaneous flow rate mode indicator lamp 43 of the display unit 4a. The 7-segment display 41 displays the detected gas instantaneous flow rate (the value obtained by converting the detected value in the flow sensor 12 into the instantaneous flow rate of the gas flowing through the pipe P) in real time. On the other hand, when the integrated flow mode is set by operating the down key 53 or the up key 54 of the operation unit 4b, the CPU 31 turns on the integrated flow mode indicator lamp 42 of the display unit 4a as shown in FIG. The 7-segment display 41 displays the integrated value of the detected instantaneous flow rate of the gas. When the integrated value of the instantaneous flow rate is 6 digits or more, the CPU 31 divides an upper digit of 6 digits or more and a lower digit of 5 digits or less and alternately displays them on the 7-segment display 41 every predetermined time. Like that.

When the execution key 55 is pressed and the end of the detection period is set, the CPU 31 detects the instantaneous gas flow rates (Q ₁ , Q ₂ ,..., Q detected by the flow sensor 12 and stored in the RAM 34 during the detection period. _N-1 and Q _N ) to obtain flow rate information. For example, as shown in FIG. 8, the CPU 31 detects the detection period (0 to T) based on the instantaneous gas flow rates (Q ₁ , Q ₂ ,..., Q _N−1 , Q _N ) stored in the RAM 34. _N ), the maximum value Q _MAX , the minimum value Q _MIN , and the average value Q _AVE are calculated, stored in the RAM 34 as flow rate information, and the stored flow rate information is displayed on the 7-segment display 41.

When displaying the maximum value Q _MAX , the minimum value Q _MIN , and the average value Q _AVE as the flow rate information, the CPU 31 displays each information in a predetermined order, for example, the maximum value Q _MAX , the minimum value Q _MIN , and the average value Q _AVE . They can be displayed on the 7-segment display 41 in order. Alternatively, the CPU 31 displays one information selected from the maximum value Q _MAX , the minimum value Q _MIN , and the average value Q _AVE on the 7-segment display 41 by operating the left shift key 51 or the right shift key 52 of the operation unit 4b. can do. In this case, when a plurality of pieces of information are desired to be displayed, designation by an operation on the left shift key 51 or the right shift key 52 of the operation unit 4b may be repeated a plurality of times.

Further, when the end of the detection period is set, the CPU 31 calculates the maximum value Q _MAX , the minimum value Q _MIN , and the average value Q _AVE in the detection period (0 to T _N ) and automatically 7 segments. Flow rate information in the detection period can be displayed on the display 41. Alternatively, after the end of the detection period is set, the CPU 31 manually sets the maximum value Q _MAX , the minimum value Q _MIN , and the minimum value Q _MAX on the 7-segment display 41 when the user presses the display key 57 of the operation unit 4b. The average value Q _AVE can be displayed. In addition, although the Example using only one set was demonstrated, it is good to use two sets of displays if a cost permits. Visibility is improved by displaying information on elapsed time on one display and displaying flow rate information corresponding to the other display. Alternatively, the visibility is improved by displaying the display items as characters on one display and displaying numerical values on the other display. Furthermore, it is possible to improve the recognition using a display capable of displaying a plurality of items, such as a liquid crystal display or a dot matrix type display.

  In addition, the CPU 31 stores various information (information related to the instantaneous flow rate and information related to the elapsed time and time corresponding to the instantaneous flow rate) stored in the RAM 34 via the communication unit 36. Thus, it can be transferred to a device external to the flow meter 1, for example, a portable terminal device for performing various function settings for the flow meter 1 and automatic meter reading of the flow rate integrated value.

  Thus, according to the flow meter 1 in the present embodiment, the start and end of the detection period are set, and the flow rate information is acquired based on the flow rate detected by the flow sensor 12 during the detection period. Here, in order to grasp the gas usage status, the information on the time itself is not necessarily required. If a predetermined period is set and the gas flow rate is detected over the period, for example, the maximum value of the flow rate in the period Flow rate information such as minimum value and average value can be acquired, so how much gas is used in what time zone, how much flow is used in which time zone, etc. I can grasp it. Therefore, it is possible to grasp the usage status of the gas from the flow rate information acquired based on the flow rate detected during the detection period without collecting trend data that requires time information. This eliminates the need for a clock to obtain time information, and eliminates the need for equipment configuration and costs for collecting and analyzing trend data, so it has a relatively inexpensive and simple configuration, while being measured. It is possible to grasp the usage status of the fluid.

Moreover, according to the flow meter 1 in the present embodiment, the flow rate information includes at least one of the maximum value, the minimum value, and the average value of the instantaneous flow rate in the detection period, and thus in the detection period (0 to T _N ). Information of at least one of the maximum value Q _MAX , the minimum value Q _MIN , and the average value Q _AVE can be acquired.

  Moreover, according to the flowmeter 1 in this embodiment, since flow information is displayed on the 7 segment display 41, flow information can be alert | reported to a user.

In addition, according to the flow meter 1 of the present embodiment, since a plurality of information included in the flow rate information is displayed on the 7-segment display 41 in a predetermined order, the maximum value Q _MAX and the minimum value in the detection period (0 to T _N ). At least two pieces of information among the value Q _MIN and the average value Q _AVE can be automatically displayed in a predetermined order without setting the order by the user.

Further, according to the flow meter 1 in the present embodiment, information designated by the operation of the left shift key 51 or the right shift key 52 of the operation unit 4b among the plurality of pieces of information included in the flow rate information is displayed on the 7-segment display 41. Therefore, one piece of information arbitrarily designated by the user can be displayed from the maximum value Q _MAX , the minimum value Q _MIN , and the average value Q _AVE in the detection period (0 to T _N ).

Further, according to the flow meter 1 of the present embodiment, when the end of the detection period is set, information is displayed on the 7-segment display 41, so that the maximum value Q _MAX in the detection period (0 to T _N ), Information of at least one of the minimum value Q _MIN and the average value Q _AVE can be automatically displayed without requiring a user operation.

In addition, according to the flow meter 1 in the present embodiment, when the detection period is set to end, when activated by the operation of the display key 57 of the operation unit 4b, the display is displayed on the 7-segment display 41. Information on at least one of the maximum value Q _MAX , the minimum value Q _MIN , and the average value Q _AVE in (0 to T _N ) can be displayed at an arbitrary timing by the user's operation.

  In addition, the structure of this invention is not limited only to the above-mentioned embodiment, You may add a various change within the range which does not deviate from the summary of this invention.

It is a perspective view of a flow meter concerning an embodiment of the present invention. It is a perspective view which shows the state which isolate | separated the measurement part of the flowmeter of FIG. 1 from the flowmeter body part. (A) is a front view of the flow meter of FIG. 1, (B) is a side view of the flow meter of FIG. 1 (a view seen from the direction of arrow B in (A)), and (C) is a view of FIG. It is a top view (figure seen from arrow C direction of (A)) of a flow meter. It is sectional drawing in the IV-IV part of the flowmeter of FIG. 3 (B). It is a perspective view which shows the flow sensor provided in the measurement part of the flowmeter of FIG. FIG. 6 is an end view when the flow sensor of FIG. 5 is viewed from the VI-VI direction. It is a block diagram which shows the functional structure of the control part provided in the measurement part of the flowmeter of FIG. It is a map which shows the flow volume detected by the flowmeter of FIG. It is a data table which shows the flow volume and elapsed time which were detected by the flowmeter of FIG. 1A and 1B show a display unit of the flow meter of FIG. 1 and information displayed on the display unit, in which FIG. 1A shows an instantaneous flow rate, and FIG. 2B shows an integrated value of the instantaneous flow rate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Flow meter 3c ... Bypass flow path 4a ... Display part 4b ... Operation part 12 ... Flow sensor 31 ... CPU
34 ... RAM
41 ... 7 segment display 51 ... Left shift key 52 ... Right shift key 53 ... Down key 54 ... Up key 55 ... Execution key 57 ... Display key

Claims (6)

Flow rate detection means for detecting the flow rate of the fluid to be measured flowing through the predetermined flow path;
Detection period setting means for setting the start and end of a detection period for detecting the flow rate ;
Based on the flow rate detected by the flow rate detection means during the detection period, flow rate information acquisition means for acquiring flow rate information that is information relating to the flow rate during the detection period;
A flow meter comprising display means for displaying the flow rate information,
A timer for measuring an elapsed time from the start to the end of the detection period;
The flow rate detecting means detects an instantaneous flow rate of the fluid to be measured.
The flow rate information is viewed at least Tsuo含of instantaneous maximum flow rate, minimum, and average value in the detection period,
The said detection period setting means is a flowmeter which is an operation part which sets the setting and completion | finish of the said detection period by a user's operation input . The flow rate information includes at least two of a maximum value, a minimum value, and an average value of instantaneous flow rates in the detection period,
The flowmeter according to claim 1, wherein the display unit displays a plurality of pieces of information included in the flow rate information in a predetermined order. A designation means for designating at least one of the plurality of pieces of information included in the flow rate information;
The flowmeter according to claim 2, wherein the display unit displays information designated by the designation unit. The flow rate information includes at least two of a maximum value, a minimum value, and an average value of instantaneous flow rates in the detection period,
Selecting means for selecting one of a plurality of pieces of information included in the flow rate information in the detection period;
The flowmeter according to claim 1, wherein the display unit displays information selected by the selection unit. The flow meter according to any one of claims 1 to 4, wherein the display unit displays when the end of the detection period is set by the detection period setting unit. Comprising display activation means for activating the display means,
The flow meter according to any one of claims 1 to 4, wherein the display unit displays when the detection period setting unit sets the end of the detection period and when the display unit is activated by the display activation unit.

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