CN101551676B - Flow control system - Google Patents

Abstract

The invention relates to a flow control system. When the flow control cannot be performed, the flow control is automatically transferred to the opening degree control, and the control is continued without stopping the system. The normal/abnormality of the actual flow rate (QR) of the fluid measured by the actual flow rate measurement unit (25B) is determined in the actual flow rate normal/abnormality judging unit (25C). When the actual flow normal/abnormal judging part (25C) judges that it is abnormal, the connection mode of the mode switching switch (SW1) of the control mode switching part (25D) is switched, and the output from the actual flow rate is selected from the valve control part (25A). The mode (flow control mode) of the actual flow rate (QR) of the measuring part (25B) is switched to the mode (opening degree control mode).

Description

flow control system

technical field

The present invention relates to a flow control system for controlling the flow of fluid flowing through a flow path.

Background technique

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

Usually, the flow control valve, in addition to receiving the set opening signal from the air conditioner control device, also receives the actual opening signal of the valve body measured by the valve opening sensor, and controls the drive of the valve body so that the set opening signal and The actual opening signal is consistent. Such a flow control valve is called an opening control type flow control valve.

On the other hand, in recent years, it has been proposed to add a unit for detecting the actual flow rate of the fluid flowing through the flow path to the flow control valve itself, and to transmit the set flow signal corresponding to the conventional set opening degree signal from the air conditioning control device. It is sent to the flow control valve to control the drive of the valve body so that the set flow signal received in the flow control valve is consistent with the measured actual flow. Such a flow control valve is called a flow control type flow control valve.

Furthermore, among the flow control valves, as disclosed in Patent Document 3, for example, there is a flow control valve in which an opening control type and a flow control type are combined, and either opening control or flow control can be selected.

Patent Document 1: Japanese Patent Application Laid-Open No. 11-211191

Patent Document 2: Japanese Patent Application Laid-Open No. 06-272935

Patent Document 3: Japanese Patent Laid-Open No. 2003-232658

However, in the flow control valve of the above-mentioned conventional flow control type, if the unit for measuring the actual flow is abnormal, the actual flow cannot be measured, or when the measured actual flow is incorrect, since the correct flow control can no longer be performed, it has to be Stop the system.

In addition, even with a flow control valve that can select either of the above-mentioned opening control and flow control, since the control selection cannot be performed automatically, it can only be performed manually. Therefore, if the maintenance personnel do not know the unit that detects the actual flow rate, an abnormality may occur. The situation cannot be dealt with, and such problems cannot be dealt with before the maintenance personnel arrives at the scene.

Contents of the invention

The present invention was made to solve such problems, and an object of the present invention is to provide a flow control system that can automatically shift to opening degree control when flow control cannot be performed, and can continue control without stopping the system.

In order to achieve this purpose, the flow control system of the present invention is provided with: a valve body, which regulates the opening and closing amount of the flow path through which the fluid flows; a valve opening detection unit, which detects the actual opening of the valve body; A flow measurement unit, which measures the actual flow of the fluid flowing through the above-mentioned flow path; an actual flow normal/abnormal judgment unit, which judges the normal/abnormality of the actual flow of the fluid measured by the actual flow measurement unit; a mode switching unit, which When the actual flow rate normal/abnormality judging unit is judged to be abnormal, switch from the mode of selecting and outputting the actual flow rate of the fluid measured by the above-mentioned actual flow rate measuring unit as the controlled quantity to selecting and outputting the valve body detected by the above-mentioned valve opening detection unit The actual opening degree of the valve is used as the mode of the controlled quantity; the valve control unit, which takes the controlled quantity selected and output by the mode switching unit as input, controls the drive of the above-mentioned valve body, so that the controlled quantity is the same as that provided for the above-mentioned valve body. The set value of the control quantity is the same.

According to the present invention, if it is judged that the actual flow rate of the fluid measured by the actual flow rate measuring unit is abnormal, the mode of selecting and outputting the actual flow rate of the fluid measured by the actual flow rate measuring unit as the controlled amount (feedback amount) is switched to the selected output mode. The actual opening of the valve body detected by the valve opening detection unit is used as the controlled amount (feedback amount), and the driving of the valve body is controlled so that the selected output controlled amount (actual opening of the valve body) is consistent with the corresponding The set value of the control quantity provided by the valve body is consistent. Thereby, when it is judged that the actual flow rate is abnormal, it is possible to automatically switch from the previous flow rate control to the opening degree control.

In the present invention, the normal/abnormal judgment of the actual flow of the fluid measured by the actual flow measuring unit can be judged according to the value of the actual flow of the fluid measured by the actual flow measuring unit, or according to the actual flow of the fluid measured by the actual flow measuring unit The determination of the parameter value used in the measurement of the actual flow rate, or the determination based on the collection/non-collection of the parameter used in the measurement process of the actual flow rate of the fluid measured by the actual flow measurement unit.

For example, when the value of the actual fluid flow measured by the actual flow measurement unit exceeds a preset abnormal threshold, it is determined that the actual flow is abnormal. In addition, as the parameter used in the measurement of the actual flow rate of the fluid measured by the actual flow rate measurement unit, when using the upstream side pressure value or downstream side pressure value of the valve body in the flow path, the pressure value exceeds the preset abnormality threshold, or when collection cannot be made due to abnormal communication, it is judged that the actual traffic is abnormal.

In addition, in the present invention, when the judgment result in the actual flow normal/abnormal judging unit returns to normal from abnormal, the mode of selecting and outputting the actual opening degree of the valve body detected by the valve opening degree detecting unit as the controlled amount is switched to selecting In the mode of outputting the actual flow rate of the fluid measured by the actual flow rate measurement unit as the controlled quantity, when the actual flow rate can be obtained normally, the previous opening degree control can be automatically restored to the flow rate control. Usually, since the flow control can control the fluid flow more precisely than the opening control, it is better to return from the opening control to the flow control when the actual flow can be obtained normally.

According to the present invention, if the actual flow rate of the fluid measured by the actual flow rate measurement unit is judged to be abnormal, the mode of selecting the output of the actual flow rate of the fluid measured by the actual flow rate measurement unit as the controlled quantity is switched to the mode of selecting the output to be detected by the valve opening degree The actual opening of the valve body detected by the unit is used as the mode of the controlled amount, and the driving of the valve body is controlled so that the selected output controlled amount (actual opening of the valve body) and the setting of the control amount provided to the valve body If the values are the same, when the flow control cannot be performed, it will automatically transfer to the opening control, and the control can be continued without stopping the system.

Description of drawings

FIG. 1 is a system diagram of equipment showing an example of an air-conditioning control system to which the flow rate control system of the present invention is applied.

Fig. 2 is a diagram showing main parts of a flow control valve used in the air conditioning control system.

Explanation of symbols in the figure:

1: Heat source machine; 2: Pump; 3: Outlet water collection pipe; 4: Outlet water pipe; 5: Air conditioner; 6: Return water pipe; 7: Return water collection pipe; 8: Flow control valve; 9: Air supply temperature Sensor; 10: air conditioning control device; 11: coil; 12: blower; 13: pipeline; 14: valve body; 15: motor; 16: valve opening detector; 17: display; 18, 19: communication interface ;20: design flow storage unit; 21: actual flow abnormal threshold storage unit; 22: abnormal pressure threshold storage unit; 23: primary side pressure sensor; 24: secondary side pressure sensor; 25: processing unit; 25A: valve control 25B: Actual flow measurement section; 25C: Actual flow normal/abnormal judgment section; 25C1: Actual flow value monitoring section; 25C2: Pressure value monitoring section; 25C3: Communication abnormality monitoring section; 25D: Control mode switching section; 25E: Control mode notification section; SW1: mode switching switch.

Detailed ways

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

In Fig. 1, 1 is a heat source machine that generates cold and hot water, 2 is a pump that transports the cold and hot water generated by heat source machine 1, 3 is an outlet water collection pipe that mixes cold and hot water from multiple heat source machines 1, and 4 is an outlet pipe. Water pipeline, 5 is the air conditioner that accepts the supply of cold and hot water delivered from the outlet water collection pipe 3 through the outlet pipeline 4, 6 is the return water pipeline, and 7 is the heat exchange in the air conditioner 5 and then transported through the return water pipeline 6 The return water collection pipe for returning cold and hot water, 8 is a flow control valve for controlling the flow of cold and hot water from the outlet water collection pipe 3 to the air conditioner 5, and 9 is a valve for measuring the temperature of the air supply output from the air conditioner 5 Air supply temperature sensor, 10 is the air conditioner control device, 11 is the coil pipe of the air conditioner 5, and 12 is the blower.

In this air-conditioning control system, the cold and hot water that is pumped by the pump 2 and heated by the heat source machine 1 is mixed in the outlet water collection pipe 3, and supplied to the air conditioner 5 through the outlet pipeline 4, and is supplied to the air conditioner 5 through the air conditioner 5 by the return water pipeline. 6 is used as return water, returns to the return water collection pipe 7, and then is pumped by the pump 2, and circulates in the above passage. For example, during cooling operation, cold water is generated in the heat source unit 1 and the cold water is circulated. During heating operation, hot water is generated in the heat source unit 1 and circulated.

Air conditioner 5, the mixture of air (return air) and outdoor air returned to the air-conditioning control system from the controlled area is cooled or heated by the coil 11 of hot and cold water, and the cooled or heated air is used as a supply The air is sent into the controlled area through the blower 12. The air conditioner 5 is a single-stage air conditioner that uses a common coil 11 in cooling operation and heating operation.

FIG. 2 is a diagram showing main parts of the flow control valve 8 in the air conditioning control system. The flow control valve 8 is equipped with: a pipeline 13, which forms a flow path through which the hot and cold water passing through the air conditioner 5 flows in; ); motor 15, which drives the valve body 14; valve opening detector 16, which detects the actual opening of the valve body 14 as the valve opening θpv; display unit 17; communication interface 18, 19, which relays the air conditioner control device 10 Communication with a monitoring device (not shown in the figure); design flow storage unit 20; actual flow abnormal threshold storage unit 21; abnormal pressure threshold storage unit 22; primary side pressure sensor 23, which detects the valve in the pipeline 13 The pressure of the fluid on the upstream side of the body 14 is taken as the primary pressure P1; the secondary side pressure sensor 24 detects the pressure of the fluid on the downstream side of the valve body 14 in the pipeline 13 as the secondary pressure P2; and Processing section 25.

The processing unit 25 includes a valve control unit 25A, an actual flow measurement unit 25B, an actual flow normal/abnormal determination unit 25C, a control mode switching unit 25D, and a control mode notification unit 25E. The actual flow rate normal/abnormal 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 uses the primary pressure P1 of the fluid from the primary pressure sensor 23, the secondary pressure P2 of the fluid from the secondary pressure sensor 24, and the valve opening θpv from the valve opening detector 16. As input, the actual flow rate QR of the fluid flowing through the line 13 is calculated from these parameters as a measure of the actual flow rate.

The control mode switching unit 25D includes a mode switching switch SW1. The mode changeover switch SW1 controls the connection mode of this switch according to the normal/abnormal judgment result from the actual flow normal/abnormal judging unit 25C. The control of the mode switching switch SW1 will be described later. If the judgment result from the actual flow normal/abnormal judging unit 25C is normal, the connection mode connected to the contact A side is adopted. The judgment result of is abnormal, and the connection mode connected to the contact B side is adopted. In the initial state, the mode selector switch SW1 adopts the connection mode connected to the contact A side.

The valve control unit 25A, actual flow measurement unit 25B, actual flow normal/abnormal determination unit 25C, control mode switching unit 25D, and control mode notification unit 25E in the processing unit 25 can be realized by CPU processing functions according to programs.

In addition, in the present embodiment, the design flow rate storage unit 20 stores the operational design flow rate QD prescribed for the flow control valve B. As shown in FIG. In addition, the actual flow rate abnormality threshold storage unit 21 stores the value of the actual flow rate QR of the fluid flowing through the pipeline 13 measured by the actual flow rate measuring unit 25B, and defines an upper limit threshold Qth1 and a lower limit threshold Qth2 of the upper and lower limits of the normal range. In addition, the abnormal pressure threshold storage unit 22 stores an upper limit threshold P1th1 and a lower limit threshold P1th2 for the primary pressure P1 detected by the primary pressure sensor 23 , and an upper limit threshold P1th2 for the secondary pressure P2 detected by the secondary pressure sensor 24 . Values of upper threshold P2thl and lower threshold P2th2.

In addition, 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 can be collected. In other cases, when at least one pressure cannot be collected (non-collection), it is determined that the communication is abnormal, and the mode switching switch SW1 of the control mode switching unit 25D is switched to the connection mode connected to the contact B side.

Hereinafter, the characteristic processing operation in the flow control valve 8 will be described in conjunction with the functions of each part in the processing unit 25 . In addition, in this example, in order to maintain the temperature of the controlled area at the set temperature, it is assumed that the air-conditioning control device 10 selects a control setting command to select the set value of the control amount at a value of 0 to 100%, and provides it to the flow rate. Control valve 8.

(normal)

In the flow rate control valve 8 , a control setting command (0 to 100%) from the air conditioning control device 10 is supplied to the valve control unit 25A through the communication interface 18 . At this time, the mode switching switch SW1 in the control mode switching unit 25D adopts the connection mode connected to the contact point 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). In addition, at this time, the control mode notification unit 25E determines that the current control mode is the flow rate control mode based on the selected output state of the actual flow rate QR in the control mode switching unit 25D to the valve control unit 25A, and notifies the valve control mode of the content. Section 25A.

Furthermore, 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 through the communication interface 19 .

The valve control unit 25A receives the notification from the control mode notification unit 25E that the current control mode is the flow control mode, reads the design flow QD from the design flow storage unit 20D, takes the design flow QD as a 100% value, and sends the flow rate from the air-conditioning control device. The control setting command (0 to 100%) of 10 is converted into the 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 the flow rate matches the actual flow rate QR from the actual flow rate measurement unit 25B.

(when abnormal)

In the driving control of the valve body 14, the normal/abnormality of the actual flow rate QR measured by the actual flow rate measurement unit 25B is determined in the actual flow rate normal/abnormality determination unit 25C.

At this time, in the actual flow rate value monitoring unit 25C1, the value of the actual flow rate QR from the actual flow rate measurement unit 25B is input, and the value of the actual flow rate QR is compatible with the upper limit threshold value Qth1 and the upper limit threshold value Qth1 stored in the actual flow rate abnormal threshold storage unit 21. Compared with the lower limit threshold Qth2, when the value of the actual flow rate QR does not enter the normal range defined by the upper and lower limit thresholds for a predetermined period of time, the actual flow rate QR is judged to be abnormal.

In the pressure value monitoring unit 25C2, the value of the primary pressure P1 from the primary pressure sensor 23 and the value of the secondary pressure P2 from the secondary pressure sensor 24 are input and stored in the abnormal pressure threshold storage unit 22. Comparing the upper limit threshold P1th1 and the lower limit threshold Plth2 for the primary pressure P1, and the upper limit threshold P2th1 and the lower limit threshold P2th2 for the secondary pressure P2, at least one of the primary pressure P1 value and the secondary pressure P2 value does not enter the upper limit. When the state within the normal range defined by the lower limit threshold continues for a predetermined time, the actual flow rate QR is judged to be abnormal.

The communication abnormality monitoring unit 25C3 receives the primary pressure P1 from the primary pressure sensor 23 and the secondary pressure P2 from the secondary pressure sensor 24 as inputs, and the primary pressure sensor 23 or the secondary pressure sensor 24 failure, or communication abnormalities such as the communication line being cut off, when the primary pressure P1 and the secondary pressure P2 cannot be collected (when not collected), it is judged as abnormal.

The actual flow value monitoring part 25C1, the pressure value monitoring part 25C2, and the communication abnormality monitoring part 25C3, if it is judged that the actual flow rate QR is abnormal, send the judgment result to the control mode switching part 25D, and the mode switching switch SW1 in the control mode switching part 25D Switches to the connection mode for connecting to the contact B side.

Thus, the actual opening degree θpv from the valve opening degree detector 16 is input to the valve control unit 25A as a controlled amount (feedback amount) instead of the actual flow rate QR from the actual flow rate measurement unit 25B. In addition, at this time, the control mode notification unit 25E judges that the current control mode is the opening degree control mode based on the selected output state of the actual opening degree θpv in the control mode switching unit 25D to the valve control unit 25A, and notifies the content to the valve control unit 25A. The valve control unit 25A.

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

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

Thus, when it is judged that the actual flow rate QR is abnormal, the previous flow rate control is automatically switched to the opening degree control, and the control can be continued without stopping the system.

(return to normal from exception)

If the judgment result in the actual flow normal/abnormal judging part 25C is to return to normal from abnormal, that is, if the actual flow value monitoring part 25C1, the pressure value monitoring part 25C2, and the judgment results in the communication abnormal monitoring part 25C3 are all normal, then the control mode The mode selection switch SW1 in the switching unit 25D is switched to the connection mode connected to the contact A side.

Accordingly, the actual flow rate QR from the actual flow rate measurement unit 25B is input as the controlled amount (feedback amount) to the valve control unit 25A instead of the actual opening degree θpv from the valve opening degree detector 16 . In addition, at this time, the control mode notification unit 25E determines that the current control mode is the flow rate control mode based on the selected output state of the actual flow rate QR in the control mode switching unit 25D to the valve control unit 25A, and notifies the valve control mode of the content. Section 25A.

The valve control unit 25A receives the notification from the control mode notification unit 25E that the current control mode is the flow control mode, reads the design flow QD from the design flow storage unit 20D, sets the value of the design flow QD to 100%, and transfers the flow rate from the air conditioner. The control setting command (0 to 100%) of the 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 the flow rate matches the actual flow rate QR from the actual flow rate measurement unit 25B.

As a result, when the actual flow rate QR is normally obtained, the previous opening degree control is automatically returned to the flow rate control. In general, flow control provides more precise control of fluid flow than opening control. Therefore, in the present embodiment, when the actual flow rate QR is normally obtained, the opening degree control is returned to the flow rate control.

Claims (3)

1. A flow control system, characterized in that, possesses the following components and integrally constitutes a flow control valve by these components: a conduit forming a flow path through which fluid flows; a valve body, which adjusts the opening and closing amount of the above-mentioned flow path; an electric motor, which drives the above-mentioned valve body; A valve opening detection unit, which detects the actual opening of the valve body; a primary side pressure sensor that measures the fluid pressure on the upstream side of the valve body in the pipeline as the primary pressure; a secondary side pressure sensor that measures the fluid pressure on the downstream side of the valve body in the pipeline as the secondary pressure; An actual flow rate measurement unit that measures based on the primary pressure detected by the primary side pressure sensor, the secondary pressure detected by the secondary side pressure sensor, and the actual opening detected by the valve opening detection unit The actual flow rate of the fluid flowing through the above flow path; an actual flow normal/abnormal judging unit, which judges whether the actual flow of the fluid measured by the actual flow measuring unit is normal/abnormal; A mode switching unit that switches from a mode in which the actual flow rate of the fluid measured by the above-mentioned actual flow measurement unit as the controlled amount is selected to be output when the above-mentioned actual flow rate normal/abnormality judging unit is judged to be abnormal, to a mode where the output is selected by the valve opening detection The actual opening of the valve body detected by the unit is used as the mode of the controlled quantity; and A valve control unit that takes the controlled quantity selected and output by the mode switching unit as input, and controls the drive of the valve body realized by the motor so that the controlled quantity and the set value of the control quantity provided to the valve body consistent, In the actual flow rate normal/abnormal judging means, the value of the primary pressure from the primary side pressure sensor and the value of the secondary pressure from the secondary side pressure sensor are used as inputs, and the primary pressure The upper threshold and the lower threshold of the above-mentioned secondary pressure are compared with the upper threshold and the lower threshold of the above-mentioned secondary pressure. When the state within the normal range defined by the upper and lower limit thresholds continues for a predetermined time, it is determined that the actual flow rate is abnormal. 2. A flow control system, characterized in that it has the following components and is integrally formed by these components into a flow control valve: a conduit forming a flow path through which fluid flows; a valve body, which adjusts the opening and closing amount of the above-mentioned flow path; an electric motor, which drives the above-mentioned valve body; A valve opening detection unit, which detects the actual opening of the valve body; a primary side pressure sensor that measures the fluid pressure on the upstream side of the valve body in the pipeline as the primary pressure; a secondary side pressure sensor that measures the fluid pressure on the downstream side of the valve body in the pipeline as the secondary pressure; An actual flow rate measurement unit that measures based on the primary pressure detected by the primary side pressure sensor, the secondary pressure detected by the secondary side pressure sensor, and the actual opening detected by the valve opening detection unit The actual flow rate of the fluid flowing through the above flow path; an actual flow normal/abnormal judging unit, which judges whether the actual flow of the fluid measured by the actual flow measuring unit is normal/abnormal; A mode switching unit that switches from a mode in which the actual flow rate of the fluid measured by the above-mentioned actual flow measurement unit as the controlled amount is selected to be output when the above-mentioned actual flow rate normal/abnormality judging unit is judged to be abnormal, to a mode where the output is selected by the valve opening detection The actual opening of the valve body detected by the unit is used as the mode of the controlled quantity; A valve control unit that takes the controlled quantity selected and output by the mode switching unit as input, and controls the drive of the valve body realized by the motor so that the controlled quantity and the set value of the control quantity provided to the valve body consistent; and An actual flow abnormal threshold storage unit, which stores an upper limit threshold and a lower limit threshold of the actual flow, In the above-mentioned actual flow normal/abnormal judgment unit, the value of the actual flow from the above-mentioned actual flow measurement unit is used as an input, and the value of the actual flow is compared with the above-mentioned upper limit threshold and the above-mentioned lower limit stored in the above-mentioned actual flow abnormality threshold storage unit The actual flow rate is judged to be abnormal when the value of the actual flow rate has not been within the normal range defined by the upper limit threshold and the lower limit threshold for a predetermined period of time. 3. The flow control system according to claim 1 or 2, characterized in that, The above-mentioned mode switching unit selects and outputs the actual opening degree of the valve body detected by the above-mentioned valve opening degree detecting unit as the controlled amount when the judgment result in the above-mentioned actual flow normal/abnormal judging unit is returned from abnormal to normal , switch to the mode of selecting and outputting the actual flow rate of the fluid measured by the above-mentioned actual flow measurement unit as the controlled quantity.

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