JP4596474B2 - Flow control device - Google Patents

Description

  The present invention relates to a flow control device that is easy to handle and highly versatile.

  In various industrial processes, process processing is often performed while supplying a predetermined fluid (for example, process gas) at a predetermined flow rate. For such fluid supply amount (flow rate) control, a valve mechanism using a proportional solenoid is exclusively used. This type of valve mechanism varies the valve opening according to the energization current of the proportional solenoid, thereby adjusting the flow rate of the fluid flowing through a predetermined flow path, and is also referred to as a proportional solenoid valve. Incidentally, the flow rate control device using the valve mechanism (proportional solenoid valve) detects the flow rate of the fluid flowing through the flow path with a flow rate sensor provided in the flow path, and the difference between the detected flow rate and the set flow rate. The valve opening degree of the valve mechanism is feedback-controlled according to the above (for example, see Patent Document 1).

The flow sensor is, for example, a pair of temperature sensitive resistance elements Ru, Rd arranged in the fluid flow direction with the heating resistance element Rh interposed therebetween, and the degree of diffusion of heat generated from the heating resistance element Rh. A thermal micro flow sensor that detects the flow rate (mass flow rate) of the fluid from the change in resistance value due to the heat of the temperature sensitive resistance elements Ru and Rd by utilizing the fact that the (temperature distribution) changes due to the flow of the fluid. Is used (see, for example, Patent Document 2). However, in this type of microflow sensor, when the type of fluid (density, specific heat, thermal conductivity, etc.) is different, the output signal changes even at the same flow rate (for example, patent document). 3).
Japanese Patent Laid-Open No. 06-341880 JP-A-4-230808 JP 2004-85489 A

  By the way, the property of the flow rate sensor (micro flow sensor) described above means that the measurable flow rate range changes depending on the type of fluid. Therefore, in a flow control device constructed using this type of flow sensor (micro flow sensor), the controllable flow range varies depending on the type of fluid to be controlled due to the measurement characteristics of the flow sensor. I can't deny it.

  Therefore, conventionally, a dedicated flow rate control device corresponding to the type of fluid to be controlled and its control flow rate range is exclusively used. However, for manufacturers, it is necessary to manufacture a wide variety of flow control devices according to the type of fluid and the control flow range. On the other hand, for each flow control device with various specifications incorporated in the industrial process, the failure There is a problem that there is a lot of waste because it is necessary to prepare a plurality of flow control devices of the same specification in preparation for the above. In other words, the conventional general flow control device has a problem that it is poor in versatility.

  In view of such circumstances, for example, it is conceivable to change and set the maximum controllable flow rate (control range) in the flow control device according to the type of fluid to be controlled, and to make the flow control device versatile. Yes. Specifically, the maximum flow rate that can be controlled by the flow control device varies depending on the type of fluid (density, specific heat, thermal conductivity, etc.), so that it matches the flow control range (flow control width) defined by the maximum flow rate. A flow rate setting value for controlling the flow rate is set. However, in this case, not only the change of the type of fluid to be controlled but also the change operation of the control flow rate range according to the type is required, so that the handling (change setting operation) is very troublesome. there were. In addition, it is necessary to examine in advance the maximum flow rate that can be controlled by the flow rate control device according to the type of fluid (density, specific heat, thermal conductivity, etc.).

  The present invention has been made in view of such circumstances, and its purpose is to easily perform various change setting operations according to the type of fluid, etc., and to easily check the setting information. An object of the present invention is to provide a highly versatile flow rate control device that can grasp the operation specifications and is excellent in handling.

In order to achieve the above-described object, the flow rate control device according to the present invention controls the flow rate control valve by proportionally controlling the opening of the flow rate control valve so that the flow rate of the fluid measured by the thermal flow rate sensor becomes the flow rate set value. Controlling the flow rate of the fluid flowing through
<a> A table in which the maximum flow rate that can be measured by the thermal flow sensor is registered in association with the type of fluid,
<b> Type setting means for setting the type of fluid to be controlled via the flow control valve;
<c> Referring to the table according to the set fluid type, obtain the maximum flow rate of the fluid that can be controlled through the flow control valve, and automatically set the maximum control range with this maximum flow rate as a full scale. Range setting means to set;
<d> When the relative value with respect to the automatically set maximum control range is instructed, or when the maximum flow rate to be controlled is specified as the flow value within the maximum control range, the instructed relative value or maximum flow rate value The operation control range is manually set according to the range, and when the operation control range is manually set according to the relative value, range changing means for limiting the number of effective digits of the range value to be displayed is provided.

Incidentally, the flow rate set value is an n-bit digital value whose variable range is within the operation control range, or an analog DC voltage value of 0 to 5 V or 1 to 5 V corresponding to this digital value, or an analog current of 4 to 20 mA. Given as a value. Preferably , the range setting means has a function of displaying the maximum flow rate of the automatically set maximum control range and prompting manual setting of the operation control range by the range changing means. Further, the range changing means displays varied display form of the maximum flow rate of the operational control range that is set according to the relative value of the maximum control range, and a display form of the maximum flow rate of the operational control range set in accordance with the flow rate set value with each other It is desirable to have a function .

  In the flow control device having the above-described configuration, the type setting unit, the range setting unit, and the range changing unit perform operation control so that the function works only when the function setting mode is set. In addition, the apparatus includes a device information display mode that operates independently of the function setting mode and that confirms and displays the setting information set by the type setting unit, the range setting unit, and the range changing unit. . These function setting mode and device information display mode are preferably configured to be set alternatively by a special operation set in advance, which is different from the information input operation of the information input key provided in the flow control device. .

  According to the flow control device having the above configuration, the maximum control range that can be controlled by the flow control device is automatically set according to the type only by inputting information on the type of fluid to be controlled. Various change setting operations accompanying the type change can be performed very easily. Moreover, even if you do not know (without checking) the density, specific heat, thermal conductivity, etc. of the fluid to be changed, and the maximum flow rate (specification) of the flow control device that can control the fluid, just specify the type of fluid. Since the above change setting operations can be automatically executed at once, the handling thereof is very simple.

  When the control range is to be changed, the relative value with respect to the maximum flow range automatically set as described above is set as a percentage given as, for example, 80% or a ratio such as 1/2, or within the maximum control range. If the maximum flow rate to be set in is directly specified, the actual operation control range (variable range of the flow rate setting value) is set based on the above maximum flow rate range. This can be done easily, and in this respect, the handling can be facilitated.

Incidentally, the display form of the maximum flow rate of the operational control range that is set according to the relative value of the maximum control range, if to be displayed at different each other and a display form of the maximum flow rate set operational control range in accordance with the flow rate set value For example, even when the display flow rate is roughly displayed by limiting the number of effective display digits, it is possible to reliably change the control range without being confused by the display data.

  Furthermore, by providing the device information display mode described above, when checking the setting information set by the range setting means and the range changing means, a problem that the information is erroneously changed or deleted can be obviated. Can be prevented. Therefore, even if the information specifying the specifications is set for the flow control device having generality, and a special specification is set for the flow control device, the specification is mistakenly lost. The effect of not inviting a malfunction such as the above is achieved.

Hereinafter, a flow control device according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing a schematic configuration of a flow rate control device. In general, a flow rate control valve 20 incorporated in a flow path body 10 and the flow rate of fluid by proportionally controlling the valve opening degree of the flow rate control valve 20. And a control unit 40 for controlling the operation. The flow channel body 10 generally includes a round hole-shaped upstream flow channel 11 bored from one end side thereof to a predetermined depth, and a round hole-like downstream flow channel 12 bored from the other end side. Each of the flow passages 11 and 12 includes a block body in which communication holes 13 and 14 communicating with the bottoms of the flow passages 11 and 12 are opened on the side portion (upper side in the drawing) of the flow passage body 10.

  A solenoid type flow control valve 20 is attached to the communication holes 13 and 14 of the flow path body 10. The solenoid flow control valve 20 includes a valve body 23 at the tip of a thrust shaft 22 that is driven forward and backward by a solenoid 21, and a clearance (valve opening degree) between the valve seat 24 facing the valve body 23 and the valve body 23. ). In particular, the flow control valve 20 has a shape in which the valve body 23 with respect to the valve seat 24 is flattened. The flow control valve 20 serves as a shut-off valve that blocks the flow path by closing the valve seat 24 with the valve body 23. It has a function. The solenoid 21 is energized and the valve body 23 is pulled away from the valve seat 24, whereby the valve opening (the gap between the valve body 23 and the valve seat 24) is varied, and the fluid flow rate (flow rate) is proportional. It has a function to control.

  In addition, here, the outside of the valve body 23 in the flow control valve 20 is connected to the upstream flow path 11 through the communication hole 13, and the inside (valve seat 24 side) of the valve body 23 is connected through the communication hole 14. By connecting to the downstream flow path 12, a so-called flow to close type valve that controls the flow rate of the fluid flowing from the outside to the inside of the valve is realized. The fluid (gas) introduced into the upstream flow path 11 of the flow path body 10 is guided to the downstream flow path 12 through the flow control valve 20 having such a structure.

  A plurality of rectifying wire meshes (rectifying bodies) 15 are fitted in the inlet portion of the upstream flow path 11 in the flow path body 10 so as to overlap each other. These rectifying metal meshes 15 play a role of rectifying the fluid (gas) introduced into the upstream flow path 11 so that the fluid (gas) smoothly flows along the flow path. In addition, a flow rate sensor 30 is provided on the downstream wall surface of the rectifying wire mesh 15 in the upstream flow path 11, and the upstream flow path 11 is connected to the upstream flow path 11 via the flow path body 10. The flow rate of the flowing fluid is detected. Incidentally, the flow rate sensor 30 has a structure in which a pair of temperature sensors are provided with a heating element sandwiched in the direction of fluid flow, and a change in temperature distribution due to the flow velocity (flow rate) of the fluid is detected by the pair of temperature sensors. It consists of a thermal flow sensor (microflow sensor) that detects the mass flow rate of the lever.

  As described above, the flow rate control device in which the solenoid-type valve mechanism 20 is attached to the flow path block 10 in which the predetermined flow path is formed and the flow rate sensor (microflow sensor) 30 is incorporated is a microprocessor (CPU) 41. The operation is controlled by the main control unit 40. The microprocessor 41 inputs switch operation information instructed from a setting / display unit 42 as a man-machine interface via a switch input circuit 43, and sets a flow rate setting value (digital command value) and other operating conditions. Etc. are set. The microprocessor 41 basically monitors the output (flow rate) of the flow rate sensor 30 via the sensor signal processing circuit 44, and the flow rate control means 41e controls the proportional valve drive circuit so that the flow rate becomes the flow rate set value. (Control valve drive circuit) By controlling the operation of 45, the energizing current of the solenoid 21 is varied, thereby controlling the operation of the valve mechanism 20, specifically the valve opening degree.

  The microprocessor 41 receives an operation switching request such as forcing the valve mechanism 20 to be fully closed or fully opened via the external contact input circuit 46. The microprocessor 41 includes an analog setting input circuit 47 for inputting the flow rate setting value for the above-described flow rate control as voltage information (analog voltage value). When the flow rate setting value is input by this analog input voltage value instead of the key switch input from the setting / display unit 42, the analog input voltage value side is valid under the setting instruction from the setting / display unit 42 in advance. It is necessary to switch so that Further, the microprocessor 41 has a function of communicating information with an external device (for example, a personal computer) not shown via the communication interface 48 and a function of storing predetermined information using a memory 49 such as an EEPROM. Yes.

  Further, the microprocessor 41 appropriately displays information such as the flow rate obtained from the flow rate sensor 30 through the display output circuit 50 on the setting / display unit 42 through its operation, and the control flow rate measurement value as an analog voltage. An analog output circuit 51 that converts the value into an external output and an event / alarm output circuit 52 that outputs information such as an abnormality alarm are provided. Incidentally, the analog output circuit 51 outputs a standard analog voltage of 0 to 5 V or 1 to 5 V as a control voltage, for example, according to the control flow rate measurement value.

  Furthermore, the microprocessor 41, for example, under the setting instruction from the setting / display unit 42 described above, the correspondence between the flow rate setting value (digital command value) and the analog input voltage, and the control flow rate measurement value and the analog output voltage. Analog scaling means 41d for setting the correspondence is provided. The analog scaling means 41d is configured to variably set the flow rate setting value and the control flow rate measurement value corresponding to the upper limit (that is, 5V) of the analog DC voltage of 0 to 5V or 1 to 5V as the analog scaling setting value. .

  Basically, the present invention is characterized by the flow rate control apparatus configured with the above-described functions. The type of fluid (gas) to be controlled is selectively specified as a function of the microprocessor 41. A gas type setting function (type setting means) 41a is provided. Further, the maximum flow rate that can be controlled through the flow rate control valve 20 according to the gas type (fluid type) set by the gas type setting function 41a is obtained, and the maximum control range with the maximum flow rate as a full scale is obtained. The range setting means 41b for automatic setting is provided.

  Further, when an instruction to change the control range is given from the setting / display unit 42, the microprocessor 41 actually sets the maximum control range automatically set by the range setting means 41b according to the instruction information. A range changing means 41c for changing to an operation control range when operating the control device is provided. By the function of the range changing means 41, the variable range of the flow rate setting value (digital command value) input by operating the setting / display unit 42 is limited to the operation control range. Further, the flow rate control means 41e controls the operation of the proportional valve drive circuit (control valve drive circuit) 45 described above according to the flow rate set value.

  Here, the gas type setting function (type setting means) 41a, the range setting means 41b, and the range changing means 41c will be described in more detail. The flow rate configured to include this type of thermal flow sensor (microflow sensor) 30 is described. In the control device, as described above, the sensor sensitivity changes depending on the type of fluid (gas) (density, specific heat, thermal conductivity, etc.), so the flow rate range that can be controlled by the type of fluid (gas) to be controlled. Changes. For example, even in the case of standard air, or a flow control device capable of controlling a flow rate of up to 50.0 L / min in the case of nitrogen, oxygen, etc., in the case of carbon dioxide, only a maximum flow control of 30.0 L / min is possible. In the case of propane gas, only 16.0 L / min flow control can be performed, and in the case of butane gas, only 10.0 L / min flow control can be performed. Therefore, it is necessary to change and set the upper limit (control range) of the flow rate controlled by the flow rate control device according to the type of fluid (gas) to be controlled.

  Therefore, in this flow control device, in the memory 49 such as the above-described EEPROM, the description is made by associating the types of some fluids (gases) to be controlled with the maximum flow rate at which the fluid can be controlled. The registered table is registered. When the fluid type is selectively designated from the setting / display unit 42 described above, the fluid type designated by the gas type setting means 41a is registered in the memory 49, and at the range setting means 41b. The maximum flow rate of the specified fluid type is obtained with reference to the table, and the maximum control range in the flow control device is automatically set according to the maximum flow rate.

  Specifically, the flow control device is normally initially set with an operation specification such as a maximum control range using air as a standard specification at the time of shipment from the factory. Therefore, when the type of fluid to be controlled is specified when using the flow control device, information on the type is input from the setting / display unit 42. This type information is input by assigning a series of management numbers according to, for example, the type of fluid, and sequentially displaying the management numbers on the setting / display unit 42 while associating them with the desired fluid type. When the management number is displayed, it is performed by pressing the enter key (ENTR).

  Next, in accordance with the specified fluid type, the maximum control range that can be controlled by the flow rate control device is automatically set by the range setting means 41 in accordance with the maximum control flow rate obtained from the table. At the same time, the maximum flow rate of the automatically set maximum control range is displayed on the setting / display unit 42 to prompt the setting person (operator) to confirm. The setter (operator) determines whether or not the control range needs to be changed by comparing the displayed maximum control flow rate with the flow rate to be actually controlled.

  Then, when it is determined that the maximum value of the flow rate to be actually operated and controlled is smaller than the maximum control flow rate and it is necessary to change the control range, the control range is changed. The control range can be changed by inputting information such as setting the control range to [1/2] or [1/3] from the setting / display unit 42 or the maximum control range. This is done by inputting relative information on the full scale as 100% and the percentage of the control range. Of course, it is of course possible to directly input the maximum flow rate of the control range to be changed within the above-mentioned maximum control range.

  When the control range change information is given in this way, the range change means 41c changes the control range based on the designated information and sets the operation control range. Specifically, when ratio information of [1/2] or percentage information of 50% is given, for example, when the full scale of the maximum control range is set as 50.0 L / min, the full scale is An operation control range of 25.0 L / min is set. When the control range is not changed, the maximum control range set as described above is set as the operation control range as it is.

  Thus, according to the flow control device in which the control range is set as described above, the maximum control range according to the fluid type can be easily set regardless of the type of fluid to be controlled. The operation control range (variable range of the flow rate setting value) can be easily set according to the flow rate to be controlled based on the maximum control range. In particular, the maximum control range that can be controlled by the fluid control device can be simplified simply by specifying the fluid type without knowing (not checking) the density, specific heat, thermal conductivity, etc. of the fluid that varies depending on the type of fluid. Can be set optimally. Accordingly, the operation specification setting operation is troublesome as in the case of the conventional flow rate control device flow rate, and there is no inconvenience that a setting error is likely to occur due to this.

  That is, when a flow rate control device initially set to a control range of 50.0 L / min for air is used for carbon dioxide gas, conventionally, information indicating that it has been changed to carbon dioxide gas, and further its control range. However, according to the flow control device of the present invention, the maximum control range is automatically set only by changing the fluid type to carbon dioxide. Therefore, there is an advantage that the setting change operation is very easy and there is almost no risk of setting mistakes.

  Moreover, if the control range automatic setting function described above is provided, the maximum control flow rate in the maximum control range can be regarded as 100% regardless of the type of fluid, and if the operation control range is set relative to this, this can be achieved. Accordingly, the variable range of the flow rate setting value is automatically set. Therefore, even in the case of constructing a fluid mixer that mixes a plurality of types of fluids (gases) using a plurality of flow rate control devices in parallel, depending on the type of fluid and the mixing ratio thereof for each flow rate control device. If each operation control range is set so that the specified control flow rate is the maximum value, the analog DC voltage (flow rate setting value) of 0 to 5V is variably controlled. Effects such as being able to perform flow rate control are exhibited.

  By the way, when the operation control range is set by the relative value described above, for example, in increments of 1%, the maximum control flow rate may not be accurately set to a desired control flow rate depending on the type of fluid. For example, in a flow control device that constructs a fluid mixer, if the control flow rate of carbon dioxide gas, which is obtained with a maximum control range of 30.0 L / min, is set to 10.0 L / min according to the mixing ratio, operation control When 34% is input as a set value for defining the range, the maximum flow rate is 10.2 L / min, and when the set value is input as 33%, the maximum flow rate is 9.9 L / min. However, in general usage forms of flow control devices, only the upper two digits of flow control accuracy are required, so the display is limited to the upper two digits by truncating or rounding off the third digit. There is almost no problem in practical use. On the contrary, if the control flow rate cannot be set accurately, the handling operation can be facilitated (simplified) as long as troubles such as frustration in the setting operation do not occur.

  However, when it is necessary to set an accurate flow rate as seen in the fluid mixer described above, the flow rate value can be directly input as a numerical value, and the control range can be set according to the numerical value. This makes it possible to control the flow rate with high accuracy. At this time, the flow rate set value to be displayed on the setting / display unit 42 is roughly displayed with only the upper two digits being valid by the above-described designation of the relative value, or conversely, it is accurately set by directly inputting a numerical value. It becomes impossible to identify whether the displayed information is displayed. Therefore, the display format may be changed. For example, when displaying the control flow rate (control range) set by direct numerical input, display the control flow rate (control range) set by inputting a relative value, for example, by displaying a minus sign at the beginning. It may be different from the form.

  Specifically, the maximum control flow rate in the maximum control range (100%) with respect to carbon dioxide is 30.0 L / min. Displayed as 34%, and the maximum flow rate set thereby is displayed as 10.0 L / min. However, when it is necessary to set the control flow rate accurately, if the relative control range is displayed as -34% and the maximum flow rate set by this is displayed as 10.2 L / min, It is possible to easily identify whether or not the display value is an approximate display with the third digit or less omitted. Therefore, providing such a display function is suitable when it is necessary to set the operation specifications of the fluid control device with high accuracy when constructing the fluid mixer described above.

  By the way, in such a flow rate control device that has versatility and is used by changing and setting the control range in accordance with the type of fluid and the flow rate to be controlled, the setting contents (setting information) are often used. I want to confirm. In this case, generally, the setting / display unit 42 generally sets the function setting mode, displays the current setting information, and monitors the current setting information for confirmation. However, at this time, the setting information itself may be changed by mistake, and the previously set information may not be restored.

  Therefore, in the flow control device according to this embodiment, the function setting mode can be set as follows, and a device information display mode that can only check the setting information can be set independently of the function setting mode. It is configured. In other words, the type setting unit 41a, the range setting unit 41b, and the range changing unit 41c described above are controlled so that their functions work only when the function setting mode is set, and the device information display mode is the type. The setting unit 41a, the range setting unit 41b, and the range changing unit 41c are set so that only the confirmation display of the setting information can be performed.

  In the setting / display unit 42, for example, when the power is turned on as shown in FIG. 2, the instantaneous flow rate is displayed on the display, and the display switching key (DISP key) 42a shown in FIG. 1 is pressed. Each time, the display contents are cyclically switched from the instantaneous flow rate display to the integrated flow rate display, the set flow rate display, and the valve drive current display. In the process of displaying information, for example, when the cursor key 42b and the enter key 42c are simultaneously pressed for a predetermined time (for example, 3 seconds) or longer (so-called long-pressed), this is used as a normal key. The function setting mode described above is set by determining that the operation is different. Further, in the setting / display section 42, when another cursor key 42d is pressed for a long time, a parameter setting mode is set by this, and when another cursor key 42e is pressed for a long time, a device information display mode is set by this. It is supposed to be. Each of these modes is canceled by pressing the device operation key (RUN key) 42f, thereby returning to the normal display mode.

  Thus, if the function setting mode and device information display mode are set in this way, if the device information display mode is set and the current setting information is confirmed, the setting information is changed by mistake. This will not cause any trouble. In addition, regarding the function setting mode, since the cursor key 42b and the enter key 42c are pressed simultaneously, a very special key operation is required. Therefore, a clear awareness that the operation specification of the flow control device is changed. As long as there is no, the function setting mode is not set. Therefore, it is possible to prevent a problem that the operation specifications of the flow control device are changed unintentionally or accidentally, and the handling thereof can be facilitated. Therefore, there is a great practical effect that the handling of the fluid control device can be simplified (facilitated) while having versatility.

The present invention is not limited to the embodiment described above. For example, the type of fluid stored in advance in the table is typically air, nitrogen, oxygen, argon, carbon dioxide, city gas, propane gas, butane, methane, etc. Information on another type of fluid may be registered.
Further, in the embodiment, the flow rate setting value is mainly given as an n-bit digital value by operating the setting / display unit 42, but this may be given from the outside via a communication interface, or 0-5V or It may be applied as an analog DC voltage of 1 to 5 V or an analog DC current of 4 to 20 mA. Furthermore, in the embodiment, gas (gas) is targeted as a fluid to be controlled, but a liquid may be used. In addition, various modifications can be made without departing from the scope of the present invention.

1 is a schematic configuration diagram of a flow control device according to an embodiment of the present invention. The figure which shows the example of the switching control procedure of the display mode in the flow control apparatus shown in FIG.

Explanation of symbols

20 Flow control valve 30 Flow sensor (Micro flow sensor)
40 Control Unit 41 Microprocessor 41a Type Setting Unit 41b Range Setting Unit 41c Range Changing Unit 41d Analog Scaling Unit 41e Flow Control Unit 42 Setting / Display Unit 49 Memory (Table)

Claims (6)

A flow rate control device for controlling the flow rate of the fluid flowing through the flow rate control valve by proportionally controlling the opening degree of the flow rate control valve so that the flow rate of the fluid measured by the thermal flow rate sensor becomes a flow rate set value. Because
A table in which the maximum flow rate that can be measured by the thermal flow sensor in association with the type of fluid is registered;
Type setting means for setting the type of fluid to be controlled via the flow control valve;
A range in which the maximum flow rate that can be controlled through the flow rate control valve of the fluid is determined with reference to the table according to the type of the set fluid, and the maximum control range with the maximum flow rate as a full scale is automatically set. Setting means;
When a relative value for the automatically set maximum control range is specified, or when the maximum flow rate to be controlled is specified within the maximum control range, the operation control range is set according to the specified relative value or maximum flow rate value. And a range changing means for limiting the number of significant digits of the range value to be displayed when the operation control range is manually set according to the relative value .   The flow rate setting value is an n-bit digital value whose variable range is within the operation control range, or an analog DC voltage value of 0 to 5 V or 1 to 5 V or an analog current value of 4 to 20 mA corresponding to this digital value. The flow control device according to claim 1, which is given as:   The flow rate control device according to claim 1, wherein the range setting unit has a function of displaying a maximum flow rate of an automatically set maximum control range and prompting manual setting of an operation control range by the range changing unit. It features the range change means for displaying varied display form of the maximum flow rate of the operational control range that is set according to the relative value of the maximum control range, and a display form of the maximum flow rate of the operational control range set in accordance with the flow rate set value with each other The flow control device according to claim 1, comprising: The flow control device according to claim 1,
The type setting means, the range setting means, and the range changing means are controlled so that their functions work only when the function setting mode is set,
The flow rate control apparatus further comprises a device information display mode for confirming and displaying setting information set by the type setting means, the range setting means and the range changing means independently of the function setting mode. 6. The flow rate control device according to claim 5 , wherein the function setting mode and the device information display mode are alternatively set by a special operation set in advance different from the information input operation of the information input key.

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