JPS61251917A - Flow rate controller - Google Patents

Abstract

PURPOSE:To reduce the labor of an operator and to prevent the occurrence of malfunction by inputting a flow rate signal from a main pipe flow rate detector and a preliminarily determined flow rate set value to operate aperture degree of a main control valve and an auxiliary control valve by the direct control of a computer. CONSTITUTION:A main control valve 2 is inserted to a main pipe 1 of a flow rate controller, and this control valve 2 is by-passed by a by-pass pipe 4 to which an auxiliary control valve 3 is inserted. A main pipe flow rate detector 6 is arranged on the main pipe 1 below the pipe 4, and the flow rate detection signal form the detector 6 is inputted to a flow rate controller 9 consisting of a computer. The preliminarily determined flow rate set value is inputted to the controller 9 also. Aperture degree of the control valve 2 and the auxiliary control valve 3 are operated directly by the computer of the controller 9, and the labor of the operator is reduced to prevent the occurrence of malfunction and the reliability of the flow rate controller is improved.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a flow rate control device, and in particular, the opening degree of a main control valve inserted in a main pipe, and the opening degree of a main control valve inserted in a bypass pipe that bypasses the main control valve. A flow that controls the flow rate of the main piping by manipulating the opening degree of the sub-control valve.
t device.

[Technical background of the invention and its problems] Generally, in plants such as nuclear power plants and thermal power plants, bypass piping equipped with a sub-control valve is installed in the main piping, and the main piping is controlled by operating the sub-control valve. Low flow rate control of piping is in place.

FIG. 4 shows a conventional flow rate control device that performs such control, and in the figure, reference numeral 1 indicates the main pipe into which the main control valve 2 is inserted. A bypass pipe 4 is arranged to bypass the main control valve 2 of the main pipe 1 and into which the sub-control valve 3 is inserted. On the downstream side of the sub-control valve 3 of the bypass piping 4,
A bypass flow rate detector 5 is arranged to measure the flow rate flowing through the bypass pipe 4, and a main pipe flow rate detector 6 is arranged downstream of the bypass pipe 4 of the main pipe 1.

In the figure, reference numeral 7 indicates a main control valve controller that controls the opening degree of the main control valve 2, and this main control valve controller 7 inputs the flow rate signal from the main pipe flow rate detector 6.
The opening degree of the main control valve 2 is controlled based on the deviation between this value and the main control valve flow rate set value. In the figure, reference numeral 8 indicates a sub-control valve controller, which inputs the flow signal from the pipe bus flow rate detector 5 and opens the sub-control valve 3 based on the deviation from the sub-control valve flow rate set value. Manipulate degrees.

However, in such a conventional flow rate control device, a sub-control valve control system having a sub-control valve controller 8 that controls the low flow rate, and a main control valve control system having the main control valve controller 7 that controls the normal flow rate. Depending on the flow rate,
Since they each need to be controlled separately, the operator must manually switch between the control by the main control valve 2 and the control by the sub-control valve 3, which is extremely troublesome and has poor reliability. There was a problem.

[Object of the Invention 1 The present invention has been made in response to such conventional circumstances,
It is an object of the present invention to provide a flow rate control device that can automatically control the openings of a main control valve and a sub-control valve simply by changing the flow rate set value.

[Summary of the Invention] That is, the present invention provides a method for controlling the main control valve by manipulating the opening degree of a main control valve inserted in a main pipe and the opening degree of a sub-control valve inserted in a bypass pipe that bypasses the main control valve. In a flow rate control device that controls the flow rate of a pipe, a flow rate signal from a main pipe flow detector that measures the flow rate downstream of the bypass pipe of the main pipe and a predetermined flow rate set value are input, and the flow rate is controlled directly by a computer. The flow control device is characterized in that the opening degrees of the main control valve and the sub control valve are controlled.

[Embodiment of the Invention] The details of the present invention will be described below with reference to an embodiment shown in the drawings.

FIG. 1 shows an embodiment of the flow rate control device of the present invention, and in the figure, the symbol @1 indicates a main pipe into which a main control valve 2 is inserted. A bypass pipe 4 is arranged to bypass the main control valve 2 of the main pipe 1 and into which a sub-control valve 3 is inserted.

A main pipe flow rate detector 6 is arranged downstream of the bypass pipe 4 of the main pipe 1 .

In the figure, reference numeral 9 indicates a flow rate control device that performs direct computer control (DDC) using a digital computer. Enter
The opening degrees of the main control valve 2 and the sub-control valve 3 are operated by direct computer control.

FIG. 2 shows the details of such a flow rate control device 9. In this flow rate control device 9, for example, as shown by the solid curve e in FIG. 3, when the flow rate is low between a and b in the figure, , switch SW1 is turned off, switch SW2 is turned on, and digital PI control is performed using only the sub-control valve 3. Also 5
When switching the valve between 0 and 0, the flow rate setting value is kept constant (X
%), the switch SWI is set to M, and the valve opening request value S1 of the main control valve 2 is given in a ramp-like manner as a time function. At this time, switch SW2 is in the on state to keep the flow rate constant.
Digital PI control is performed by the sub-control valve 3. The switching from a low flow rate to a high flow rate is completed when the sub control valve 3 is fully opened. Further, when shifting from a high flow rate to a low flow rate, valve switching is completed when the main control valve 2 is fully opened. Furthermore, between 0 and 6, the switch SWI
is set to A, switch SW2 is turned off, and digital PI control is performed using only main control valve 2.

In Fig. 3, time is plotted on the horizontal axis, and flow rate in the main piping is plotted on the vertical axis; the dashed line f indicates the flow rate of the main control valve 2, and the dashed line q indicates the flow rate of the sub control valve 3. It shows.

[Effects of the Invention] As described above, according to the flow rate control device of the present invention, direct computer control is used, so the connection between the main control valve and the auxiliary control valve can be achieved by simply changing the flow rate setting value without the intervention of an operator. It becomes possible to reliably perform switching and main piping flow control. In addition, it is possible to reduce the labor of the operator and prevent malfunctions, and the reliability of the flow control system can be significantly improved compared to the conventional system.

[Brief explanation of the drawing]

FIG. 1 is a piping system diagram showing an embodiment of the flow rate control device of the present invention, FIG. 2 is a block diagram showing details of the flow rate control device of FIG. 1, and FIG. 3 is a flow rate control device of the present invention. A graph for explaining the control method, and FIG. 4 is a piping system diagram showing a conventional flow direction control device. 1...Main piping 2...Main control valve 3...Sub control valve 4...Bypass piping 5...Bypass flow rate detector 6 ...Main piping flow rate detector Patent attorney Sa Suyama - Figure 1 Sub-control valve flow rate setting value Figure 4

Claims (1)

[Claims] (1) Flow rate to control the flow rate of the main piping by manipulating the opening degree of the main control valve inserted in the main piping and the opening degree of the sub-control valve inserted in the bypass piping that bypasses the main control valve. In the control device, a flow signal from a main pipe flow rate detector that measures the flow rate on the downstream side of the bypass pipe of the main pipe and a predetermined flow rate set value are input, and the main control valve and the sub control valve are controlled by computer direct control. A flow control device characterized by controlling the opening degree of a valve.