JP5066474B2 - Flow control system - Google Patents

Description

  The present invention relates to a flow rate control system that controls the flow rate of a fluid flowing through a flow path.

  Conventionally, as this type of flow rate control system, there is an air conditioning control system that controls the flow rate of a heat medium (cold / warm water) to an air conditioner (see, for example, Patent Documents 1 and 2). In this air conditioning control system, a flow control valve is installed in the cold / hot water supply passage to the air conditioner, and the valve body in the flow control valve is driven to adjust the opening / closing amount of the flow path through which the cold / hot water flows. ing.

  Normally, the flow control valve receives the set opening signal from the air conditioning control device, but also receives the actual opening signal of the valve body measured by the valve opening sensor, and the set opening signal and the actual opening signal are The drive of the valve body is controlled so as to match. Such a flow control valve is called an opening control type flow control valve.

  On the other hand, in recent years, a means for measuring the actual flow rate of the fluid flowing through the flow path is added to the flow control valve itself, and a set flow signal corresponding to a conventional set opening signal is sent from the air conditioning control device to the flow control valve, There has also been proposed one that controls the driving of the valve body so that the set flow signal received at the flow control valve matches the measured actual flow rate. Such a flow rate control valve is called a flow rate control type flow rate control valve.

  Furthermore, for example, as disclosed in Patent Document 3, the flow control valve is a combination of an opening degree control type and a flow rate control type, and can select either opening degree control or flow rate control. There is also a valve.

JP-A-11-2111191 Japanese Patent Laid-Open No. 06-272935 JP 2003-232658 A

  However, in the conventional flow control valve of the above-described flow rate control type, if the actual flow rate measurement unit becomes abnormal and the actual flow rate becomes impossible to measure or the measured actual flow rate is incorrect, it is no longer accurate. Because it was not possible to control the flow rate properly, the system had to be stopped.

  In addition, even with a flow control valve that can select one of the above-described opening control and flow control, the selection of control cannot be performed automatically, but only by human. There is a problem that it cannot be dealt with if maintenance personnel do not know that an abnormality has occurred in the measuring means, and it cannot be handled until the maintenance personnel arrive at the site.

  The present invention has been made to solve such a problem. The purpose of the present invention is to automatically shift to opening degree control and stop the system when flow rate control becomes impossible. An object of the present invention is to provide a flow rate control system capable of continuing control without any problems.

In order to achieve such an object, the present invention includes a pipe line that forms a flow path through which a fluid flows, a valve body that adjusts an opening / closing amount of the flow path of the pipe line, a motor that drives the valve body, A valve opening degree detecting means for detecting an actual opening degree of the valve body driven by the motor, a primary pressure sensor for detecting a fluid pressure upstream of the valve body in the pipe line as a primary pressure, and a pipe line; A secondary pressure sensor that detects fluid pressure downstream of the valve body as a secondary pressure, a primary pressure that is detected by the primary pressure sensor, a secondary pressure that is detected by the secondary pressure sensor, The actual flow rate measuring means for measuring the actual flow rate of the fluid flowing through the flow path based on the actual opening degree detected by the valve opening degree detecting means, and the normal / abnormality of the actual flow rate of the fluid measured by the actual flow rate measuring means. The actual flow rate normal / abnormal judgment means for judging, and the actual flow normal / abnormal judgment means judges that the flow is abnormal. In this case, from the mode in which the actual flow rate of the fluid measured by the actual flow rate measuring unit is selectively output as the controlled amount, the actual opening degree of the valve body detected by the valve opening degree detecting unit is selectively output as the controlled amount. The mode switching means for switching to the mode and the controlled amount selected and output from the mode switching means are input, and the valve by the motor is set so that the controlled amount matches the set value of the controlled amount given to the valve body. A flow rate control system for controlling the flow rate of fluid flowing through a pipe using a flow rate control valve that is integrally provided with a valve control unit that controls the body drive. The normal / abnormality of the actual flow rate of the fluid is determined based on the value of the fluid pressure used in the process of measuring the actual flow rate of the fluid measured by the means.

According to this invention, the normal / abnormality of the actual flow rate of the fluid is determined based on the value of the fluid pressure used in the process of measuring the actual flow rate of the fluid measured by the actual flow rate measurement unit, and is measured by the actual flow rate measurement unit. When the actual flow rate of the fluid is determined to be abnormal, the valve detected by the valve opening degree detection unit from the mode in which the actual flow rate of the fluid measured by the actual flow rate measurement unit is selectively output as a controlled amount (feedback amount). The mode is switched to a mode in which the actual opening of the body is selectively output as a controlled amount (feedback amount), and the controlled amount that is selected and output (the actual opening of the valve body) is set to the valve body. The drive of the valve body is controlled so as to coincide with the value. Thereby, when it is determined that the actual flow rate is abnormal, the flow rate control up to that point is automatically switched to the opening degree control.

In the present invention, the normal / abnormal determination of the actual flow rate of the fluid measured by the actual flow rate measuring means may be further made based on the actual flow rate value of the fluid measured by the actual flow rate measuring means, The determination may be made based on the collection / non-collection of parameters used in the process of measuring the actual flow rate of the fluid measured by the flow rate measuring means.

For example, when the value of the actual flow rate of the fluid measured by the actual flow rate measuring unit exceeds a predetermined abnormality threshold, it is determined that the actual flow rate is abnormal. Further, when the value of the fluid pressure used in the process of measuring the actual flow rate of the fluid measured by the actual flow rate measuring unit cannot be collected due to communication abnormality, it is determined that the actual flow rate is abnormal.

  Further, in the present invention, when the judgment result in the actual flow normality abnormality judging means returns from normal to normal, the mode is such that the actual opening degree of the valve body detected by the valve opening degree detecting means is selectively outputted as the controlled amount. By switching to the mode that selectively outputs the actual flow rate of the fluid measured by the actual flow rate measuring means as the controlled amount, when the actual flow rate comes to be obtained normally, from the opening degree control until then It becomes possible to automatically return to the flow control. Generally, the flow rate control can control the fluid flow rate with higher accuracy than the opening degree control. Therefore, when the actual flow rate can be obtained normally, return from the opening degree control to the flow rate control. Is desired.

According to the present invention, normality / abnormality of the actual flow rate of the fluid is determined based on the value of the fluid pressure used in the process of measuring the actual flow rate of the fluid measured by the actual flow rate measurement unit, and is measured by the actual flow rate measurement unit. If the actual flow rate of the fluid is determined to be abnormal, the actual opening of the valve element detected by the valve opening degree detection unit is selected from the mode in which the actual flow rate of the fluid measured by the actual flow rate measurement unit is selected and output as the controlled variable. The valve body is switched to a mode that selectively outputs the degree as a controlled amount, and the controlled amount (actual opening degree of the valve body) that is selectively output matches the set value of the control amount given to the valve body. When the flow rate control cannot be performed, the shift to the opening degree control is automatically performed, and the control can be continued without stopping the system.

  Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is an instrumentation diagram showing an example of an air conditioning control system to which a flow control system according to the present invention is applied.

  In FIG. 1, 1 is a heat source device that generates cold / hot water, 2 is a pump that conveys cold / warm water generated by the heat source device 1, 3 is a forward header that mixes cold / hot water from a plurality of heat source devices 1, and 4 is a forward pipe. Line 5 is an air conditioner that receives supply of cold / warm water sent from the forward header 3 via the forward water line 4, 6 is a return water line, 7 is heat-exchanged in the air conditioner 5, and is returned via the return water line 6. A return header to which the cool / warm water sent is returned, 8 is a flow control valve for controlling the flow of cool / warm water supplied from the forward header 3 to the air conditioner 5, and 9 is for measuring the temperature of the supply air sent from the air conditioner 5 An air supply temperature sensor 10 is an air conditioning control device, 11 is a coil of the air conditioner 5, and 12 is a blower.

  In this air conditioning control system, cold / hot water pumped from the pump 2 and added with heat by the heat source device 1 is mixed in the forward header 3, supplied to the air conditioner 5 through the forward water conduit 4, and passes through the air conditioner 5. Then, the return water pipe 6 reaches the return header 7 as return water, and is pumped again by the pump 2 to circulate through the above paths. For example, in the case of the cooling operation, the heat source unit 1 generates cold water and circulates the cold water. In the case of heating operation, warm water is generated in the heat source device 1 and this warm water circulates.

  The air conditioner 5 cools or heats the mixture of air (return air) returning from the controlled area to the air conditioning control system and the outside air by the coil 11 through which cold / hot water passes, and supplies the cooled or heated air. To the control target area via the blower 12. The air conditioner 5 is a single type air conditioner that uses a common coil 11 for cooling operation and heating operation.

  FIG. 2 is a diagram showing a main part of the flow control valve 8 in this air conditioning control system. The flow rate control valve 8 includes a pipe line 13 that forms a flow path through which cold and hot water that has passed through the air conditioner 5 flows, and a valve body 14 that adjusts the flow rate of the fluid flowing through the pipe line 13 (the opening and closing amount of the flow path). The motor 15 that drives the valve body 14, the valve opening detector 16 that detects the actual opening of the valve body 14 as the valve opening θpv, the display unit 17, the air conditioning control device 10 and a monitoring device (not shown). Communication interfaces 18 and 19 that mediate communication with each other, a design flow rate storage unit 20, an actual flow rate abnormal threshold storage unit 21, an abnormal pressure threshold storage unit 22, and the valve body 14 in the conduit 13. A primary pressure sensor 23 that detects the pressure of the upstream fluid as the primary pressure P1, and a secondary pressure sensor that detects the pressure of the fluid downstream of the valve body 14 in the conduit 13 as the secondary pressure P2. 24 and a processing unit 25.

  The processing unit 25 includes a valve control unit 25A, an actual flow rate measurement unit 25B, an actual flow rate normality abnormality determination unit 25C, a control mode switching unit 25D, and a control mode notification unit 25E. The actual flow rate normality abnormality determination unit 25C includes an actual flow rate value monitoring unit 25C1, a pressure value monitoring unit 25C2, and a communication abnormality monitoring unit 25C3.

  The actual flow rate measurement unit 25B includes a primary pressure P1 of the fluid from the primary pressure sensor 23, a secondary pressure P2 of the fluid from the secondary pressure sensor 24, and a valve opening from the valve opening detector 16. Using θpv as an input, the actual flow rate QR of the fluid flowing through the conduit 13 is calculated from these parameters as a measured value of the actual flow rate.

  The control mode switching unit 25D includes a mode switch SW1. The mode changeover switch SW1 controls the connection mode of the switch based on the normal / abnormal determination result from the actual flow normal / abnormal determination unit 25C. Although the control of the mode changeover switch SW1 will be described later, if the determination result from the actual flow rate normality abnormality determination unit 25C is normal, the connection mode to the contact A side is set, and the determination from the actual flow rate normality abnormality determination unit 25C. If the result is abnormal, the connection mode to the contact B side is set. In the initial state, the mode selector switch SW1 is set to the connection mode to the contact A side.

  The valve control unit 25A, actual flow rate measurement unit 25B, actual flow normality / abnormality determination unit 25C, control mode switching unit 25D, and control mode notification unit 25E in the processing unit 25 are realized as processing functions of the CPU according to the program.

  In this embodiment, the design flow rate storage unit 20 stores an operational design flow rate QD determined for the flow rate control valve 8. The actual flow rate abnormality threshold value storage unit 21 has an upper limit threshold value Qth1 and a lower limit threshold value that define upper and lower limits of the normal range for the value of the actual flow rate QR of the fluid flowing through the pipeline 13 measured by the actual flow rate measurement unit 25B. Qth2 is stored. Further, the abnormal pressure threshold storage unit 22 includes an upper limit threshold P1th1 and a lower limit threshold P1th2 for the value of the primary pressure P1 detected by the primary side pressure sensor 23, and a secondary pressure detected by the secondary side pressure sensor 24. An upper limit threshold value P2th1 and a lower limit threshold value P2th2 for the value of P2 are stored.

The communication abnormality monitoring unit 25C3 monitors whether the primary pressure P1 detected by the primary side pressure sensor 23 and the secondary pressure P2 detected by the secondary side pressure sensor 24 are collected. If at least one of the pressures cannot be collected (during non-collection) due to a failure of the pressure sensor or disconnection of the communication line, etc., it is determined that communication is abnormal, and the mode switch SW1 of the control mode switching unit 25D is set. Switch to the connection mode to the contact B side.

  Hereinafter, characteristic processing operations in the flow control valve 8 will be described with the functions of the respective units in the processing unit 25. In this example, in order to keep the temperature of the control target area at the set temperature, a control setting command that takes a value of 0 to 100% as a set value of the control amount is given from the air conditioning control device 10 to the flow control valve 8. To do.

〔Normal〕
In the flow control valve 8, a control setting command (0 to 100%) from the air conditioning control device 10 is given to the valve control unit 25 </ b> A via the communication interface 18. At this time, the mode switch SW1 in the control mode switching unit 25D is set to the connection mode to the contact A side.

  Therefore, the actual flow rate QR from the actual flow rate measurement unit 25B is input to the valve control unit 25A as a controlled amount (feedback amount). At this time, the control mode notifying unit 25E determines that the current control mode is the flow rate control mode from the selection output state of the actual flow rate QR to the valve control unit 25A in the control mode switching unit 25D, and indicates that the Notify the control unit 25A.

  The control mode notification unit 25E displays on the display unit 17 that the current control mode is the flow rate control mode, and outputs it to the air conditioning control device 10 and the monitoring device via the communication interface 19.

  The valve control unit 25A receives the notification that the current control mode is the flow rate control mode from the control mode notification unit 25E, reads the design flow rate QD from the design flow rate storage unit 20D, and sets the design flow rate QD as a 100% value. A control setting command (0 to 100%) from the air conditioning control device 10 is converted into a flow rate. Then, a command is sent to the motor 15 to control the drive of the valve body 14 so that the control setting command converted into this flow rate and the actual flow rate QR from the actual flow rate measurement unit 25B coincide.

[In case of abnormality]
During the drive control of the valve body 14, the actual flow rate normality / abnormality determination unit 25C determines normality / abnormality with respect to the actual flow rate QR measured by the actual flow rate measurement unit 25B.

  In this case, the actual flow rate monitoring unit 25C1 receives the actual flow rate QR value from the actual flow rate measurement unit 25B as an input, and the actual flow rate QR value and the upper limit threshold value Qth1 stored in the actual flow rate abnormality threshold storage unit 21. Compared with the lower limit threshold value Qth2, if the state where the actual flow rate QR value does not fall within the normal range determined by the upper and lower limit threshold values continues for a predetermined time, it is determined that the actual flow rate QR is abnormal.

  In the pressure value monitoring unit 25C2, the value of the primary pressure P1 from the primary side pressure sensor 23 and the value of the secondary pressure P2 from the secondary side pressure sensor 24 are input and stored in the abnormal pressure threshold storage unit 22. Compared with the upper limit threshold P1th1 and lower limit threshold P1th2 for the primary pressure P1 and the upper limit threshold P2th1 and lower limit threshold P2th2 for the secondary pressure P2, at least one of the value of the primary pressure P1 and the value of the secondary pressure P2 is the upper and lower limits When the state not within the normal range determined by the threshold value continues for a predetermined time, it is determined that the actual flow rate QR is abnormal.

  In the communication abnormality monitoring unit 25C3, the primary pressure P1 from the primary side pressure sensor 23 and the secondary pressure P2 from the secondary side pressure sensor 24 are input, and the primary side pressure sensor 23 or the secondary side pressure sensor 24 If the primary pressure P1 or the secondary pressure P2 cannot be collected due to a failure or a communication abnormality such as disconnection of the communication line (when not collected), it is determined to be abnormal.

  When the actual flow rate monitoring unit 25C1, the pressure value monitoring unit 25C2, and the communication abnormality monitoring unit 25C3 determine that the actual flow rate QR is abnormal, the actual flow rate monitoring unit 25C1 sends the determination result to the control mode switching unit 25D. Switch SW1 to the connection mode to the contact B side.

  As a result, the actual opening θpv from the valve opening detector 16 is input to the valve control unit 25A as the controlled amount (feedback amount) instead of the actual flow rate QR from the actual flow rate measuring unit 25B. The At this time, the control mode notification unit 25E determines that the current control mode is the opening control mode from the selection output state of the actual opening θpv to the valve control unit 25A in the control mode switching unit 25D. Is notified to the valve control unit 25A.

  The control mode notification unit 25E displays on the display unit 17 that the current control mode is the opening control mode, and outputs it to the air conditioning control device 10 and the monitoring device via the communication interface 19.

  The valve control unit 25A receives a notification that the current control mode is the opening control mode from the control mode notification unit 25E, and receives the control setting command (0 to 100%) and the valve opening from the air conditioning control device 10. A command is sent to the motor 15 to control the drive of the valve body 14 so that the actual opening θpv from the detector 16 matches.

  As a result, when the actual flow rate QR is determined to be abnormal, the flow rate control up to that point is automatically switched to the opening degree control, and the control can be continued without stopping the system.

[Return from abnormality to normal]
When the determination result at the actual flow rate normality abnormality determination unit 25C returns from normal to normal, that is, when the determination results at the actual flow rate monitoring unit 25C1, the pressure value monitoring unit 25C2, and the communication abnormality monitoring unit 25C3 are all normal, the control mode The mode switch SW1 in the switching unit 25D is switched to the connection mode to the contact A side.

  As a result, the actual flow rate QR from the actual flow rate measurement unit 25B is input to the valve control unit 25A as the controlled amount (feedback amount) instead of the actual opening degree θpv from the valve opening degree detector 16 so far. The At this time, the control mode notifying unit 25E determines that the current control mode is the flow rate control mode from the selection output state of the actual flow rate QR to the valve control unit 25A in the control mode switching unit 25D, and indicates that the Notify the control unit 25A.

  The valve control unit 25A receives the notification that the current control mode is the flow rate control mode from the control mode notification unit 25E, reads the design flow rate QD from the design flow rate storage unit 20D, and sets the design flow rate QD as a 100% value. A control setting command (0 to 100%) from the air conditioning control device 10 is converted into a flow rate. Then, a command is sent to the motor 15 to control the drive of the valve body 14 so that the control setting command converted into this flow rate and the actual flow rate QR from the actual flow rate measurement unit 25B coincide.

  As a result, when the actual flow rate QR is normally obtained, the flow rate control is automatically restored from the opening degree control so far. In general, the flow rate control can control the fluid flow rate with higher accuracy than the opening degree control. For this reason, in the present embodiment, when the actual flow rate QR is normally obtained, the flow rate control is returned from the opening degree control.

It is an instrumentation figure showing an example of an air-conditioning control system to which a flow control system concerning the present invention is applied. It is a figure which shows the principal part of the flow control valve used in this air conditioning control system.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Heat source machine, 2 ... Pump, 3 ... Outflow header, 4 ... Outflow pipe line, 5 ... Air conditioner, 6 ... Return water pipe line, 7 ... Return header, 8 ... Flow control valve, 9 ... Supply air temperature sensor, 10 DESCRIPTION OF SYMBOLS ... Air-conditioning control apparatus, 11 ... Coil, 12 ... Air blower, 13 ... Pipe line, 14 ... Valve body, 15 ... Motor, 16 ... Valve opening detector, 17 ... Display part, 18, 19 ... Communication interface, 20 ... Design Flow rate storage unit, 21 ... Actual flow rate abnormality threshold value storage unit, 22 ... Abnormal pressure threshold value storage unit, 23 ... Primary pressure sensor, 24 ... Secondary pressure sensor, 25 ... Processing unit, 25A ... Valve control unit, 25B ... Actual flow rate measurement unit, 25C ... Actual flow rate normal / abnormal judgment unit, 25C1 ... Actual flow rate monitoring unit, 25C2 ... Pressure value monitoring unit, 25C3 ... Communication abnormality monitoring unit, 25D ... Control mode switching unit, 25E ... Control mode notification unit, SW1 Mode change switch.

Claims (4)

A conduit forming a flow path through which fluid flows;
A valve body for adjusting the amount of opening and closing of the flow path of this pipe line ,
A motor for driving the valve body;
Valve opening degree detecting means for detecting the actual opening degree of the valve body driven by the motor ;
A primary pressure sensor that detects a fluid pressure upstream of the valve body in the pipe line as a primary pressure;
A secondary pressure sensor for detecting a fluid pressure downstream of the valve body in the pipe line as a secondary pressure;
Fluid flowing through the flow path based on the primary pressure detected by the primary pressure sensor, the secondary pressure detected by the secondary pressure sensor, and the actual opening detected by the valve opening detection means An actual flow rate measuring means for measuring the actual flow rate of
Actual flow normality abnormality determining means for determining normality / abnormality of the actual flow rate of the fluid measured by the actual flow rate measurement means;
The valve detected by the valve opening degree detection means from the mode in which the actual flow rate of the fluid measured by the actual flow rate measurement means is selectively output as a controlled quantity when it is determined to be abnormal by the actual flow rate normality abnormality determination means. Mode switching means for switching to a mode for selectively outputting the actual opening of the body as a controlled amount;
The controlled quantity selected and output from the mode switching means is input, and the driving of the valve body by the motor is controlled so that the controlled quantity matches the set value of the controlled quantity given to the valve body. A flow rate control system for controlling a flow rate of a fluid flowing through the pipe using a flow rate control valve integrally provided with a valve control means ,
The actual flow normality / abnormality determination means determines normality / abnormality of the actual flow rate of the fluid based on the value of the fluid pressure used in the process of measuring the actual flow rate of the fluid measured by the actual flow rate measurement means. And flow control system. The flow control system according to claim 1,
The actual flow normality abnormality determination means further includes:
The flow rate control system, wherein normal / abnormal of the actual flow rate of the fluid is determined based on the value of the actual flow rate of the fluid measured by the actual flow rate measuring means. The flow control system according to claim 1,
The actual flow normality abnormality determination means further includes:
A flow rate control system, wherein normality / abnormality of the actual flow rate of the fluid is determined based on collection / non-collection of parameters used in the process of measuring the actual flow rate of the fluid measured by the actual flow rate measuring means. In the flow control system according to any one of claims 1 to 3,
The mode switching means is
From the mode in which the actual opening degree of the valve body detected by the valve opening degree detecting means is selectively output as the controlled amount when the judgment result in the actual flow rate normality abnormality judging means returns to normal from the abnormality, A flow rate control system characterized by switching to a mode in which the actual flow rate of the fluid measured by the measuring means is selectively output as a controlled amount .

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