JPS6365902A - Device for controlling flow rate of fed liquid to centrifugal film dryer - Google Patents

Abstract

PURPOSE:To stabilize the flow rate of fed liquid by switching over to controlling by heat tank liquid level deviation signals in case the deviation between a sensing signal from a fed liquid sensor and a preset value is as large as a fixed value of larger in the flow rate control by sensing the deviation of fed flow. CONSTITUTION:In the feed system feeding radioactive waste liquid in a liquid feed tank 5 to a centrifugal film dryer 1 through a heat tank 8, a fed quantity regulating valve 10 is provided to regulate the fed quantity. The fed quantity is sensed by a flow rate sensor 13, and a sensing signal S13 is transmitted to a flow rate control device 14, where a control signal S14 is output to regulate a flow rate regulating valve 10. On the other hand, in the head tank 8, a control system to control the fed flow rate by means of a signal of a head tank liquid level sensor is provided. When abnormal situations of deviation of the fed liquid flow rate sensor is generated, a changeover signal is output from an alarm setting device to a signal changeover device to switch over to a flow rate control by the head tank liquid level control.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a liquid supply flow rate control device for a centrifugal thin film dryer that controls the liquid supply flow rate of a centrifugal thin film dryer.

(Prior Art) A facility for pulverizing radioactive waste liquid using a centrifugal thin film dryer will be described below with reference to FIG.

Reference numeral 1 in the figure is a centrifugal thin film dryer, and a shaft 3 connected to a motor 2 is disposed inside this centrifugal thin film dryer 1, and a plurality of blades 4 are attached to this shaft 3.
The outer periphery is heated by steam. By driving the motor 2, the shaft 3 and blade 4 are rotated.

On the other hand, reference numeral 5 in the figure is a waste liquid supply tank, and this waste liquid supply tank 5 stores radioactive waste liquid generated from nuclear power generation equipment. The waste liquid supply tank 5 has pipes 6 and 7.
A head tank 8 is connected via.

A supply pump 9 is inserted into the pipe 6, and a flow rate regulating valve 10 is inserted into the pipe 7. - The radioactive waste liquid contained in the dryer tank 5 is circulated and agitated via the supply pump 9, head tank 8, and flow rate adjustment valve 10.

Further, a liquid supply pipe 11 is disposed between the head tank 8 and the centrifugal thin film dryer 1.
An on-off valve 12 is inserted in the.

A flow rate detector 13 is installed in the liquid supply pipe 11, and a detection signal s13 from this flow rate detector 13 is transmitted to the flow rate control device 1.
4 will be done manually. From this flow rate control device 14, the flow r:
A control signal s14 is output to the Li'J3 valve regulator 10.

In the above configuration, the on-off valve 12 is opened in response to a liquid supply start command, and the radioactive waste liquid is supplied into the centrifugal thin film dryer via the liquid supply pipe 11. At the same time, the flow rate control device 14
is activated and starts flow rate control. That is, flow rate detector 1
The opening degree of the flow rate regulating valve 10 is controlled based on the detection signal s13 input from the centrifugal thin film dryer 1, thereby controlling the flow rate of liquid supplied to the centrifugal thin film dryer 1. That is, the flow rate is increased linearly until a preset target flow rate is reached, and after reaching the target flow rate, that state is maintained. The radioactive waste liquid supplied into the centrifugal thin film dryer 1 is dried and concentrated as it flows down the heated centrifugal thin film dryer 1.

The slurry is then scraped off by the blade 4 and discharged.

The above configuration has the following problems. The flow rate control by the flow rate control device 14 is performed by detecting the current flow rate of liquid supplied by the flow rate detector 13 as described above, comparing this flow rate detection signal s13 with a set value, and adjusting the flow rate so that the deviation becomes zero. The opening degree of the flow rate regulating valve 10 is adjusted. In this case, as the flow rate detector 13, one that is less likely to cause pipe blockage, such as an electromagnetic type flow rate detector, is used.

However, even if such a detector is employed, detection failure may occur if waste liquid with low conductivity is distributed or if air is mixed in. If a detection failure occurs, there is a possibility that the detection signal from the flow rate detector 13 will be disturbed.

As described above, conventional liquid supply flow rate control is feedback control based on the flow rate detection signal s13 from the flow rate detector 13, so any disturbance in the flow rate detection signal s13 from the flow rate detector 13 directly results in disturbance in the liquid supply flow rate.

Such fluctuations in the supply liquid flow rate increase the load on the motor 2 on the centrifugal thin film dryer, resulting in tripping or deterioration of the powder properties produced on the centrifugal thin film dryer.

(Problems to be Solved by the Invention) As described above, the conventional flow rate control may impair the stable operation of the centrifugal thin film dryer, and the present invention was made based on this point, and its purpose is to The object of the present invention is to provide a liquid supply flow rate control device for a centrifugal thin film dryer that can provide stable operation of the centrifugal thin film dryer.

[Structure of the Invention] (Means for Solving the Problems) That is, the liquid supply flow rate control device for a centrifugal thin film dryer according to the present invention has the following features: The installed liquid supply flow rate detector compares the liquid supply flow rate detection signal from this liquid supply flow rate detector with a preset liquid supply flow rate setting signal, and uses the deviation as the liquid supply flow rate detection signal. a supply liquid flow rate deviation calculator that outputs the
The head tank liquid level detector detects the liquid level in the head tank, and the head tank liquid level detection signal from this head tank liquid level detector is compared with a preset head tank liquid level setting signal to detect the head tank liquid level. a head tank liquid level deviation calculator that outputs a liquid level deviation signal to the signal switch; and a head tank liquid level deviation calculator that outputs a liquid level deviation signal to the signal switch; and a head tank liquid level deviation calculator that outputs a liquid level deviation signal to the signal switch; A valve opening controller that adjusts the opening of a flow rate control valve inserted in the processing liquid stirring line, and a supply liquid flow rate deviation signal from the liquid supply flow rate deviation calculator are input to the liquid supply flow rate detector. It is determined whether an abnormality has occurred, and if it is determined that an abnormality has occurred, a switching signal is output to the signal switching device, and the liquid supply flow rate control is changed from liquid supply flow rate control based on the liquid supply flow rate deviation signal to liquid supply based on the head tank liquid level deviation signal. The device is characterized by being equipped with an alarm setting device that switches to flow rate control.

(Function) In other words, the alarm setting device determines whether an abnormality has occurred in the liquid supply flow rate detector based on the liquid supply flow rate deviation signal, and if it is determined that an abnormality has occurred, the The purpose is to switch from liquid flow rate control to liquid supply flow rate control using a head tank liquid level deviation signal, thereby preventing irregularities in the liquid supply flow rate due to disturbances in the liquid supply flow rate detector and various problems caused by this.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 to 3. FIG. 1 is a diagram showing the configuration of the liquid supply flow rate control device according to this embodiment, in which reference numeral 101 is a liquid supply flow rate detector and reference numeral 102 is a function generator. The feed liquid flow rate detection signal s 101 from the feed liquid flow rate detector 101 and the feed liquid flow rate setting signal 5102 from the function generator 102 (this is the reference liquid flow rate control) are both the feed liquid flow rate deviation. It is input to the computing unit 103. The above function generator 10
2 generates a function as shown in FIG. FIG. 2 is a diagram showing time changes in the liquid supply flow rate, with time on the horizontal axis and liquid supply flow rate on the vertical axis.

As shown in FIG. 2, the liquid supply flow rate is linearly increased until it reaches the target flow rate (Ql), and after reaching the target 'tAE amount (Ql), that state is maintained. The supply liquid flow rate deviation calculator 103 uses a supply liquid flow rate detection signal s.
101 and the supply liquid flow rate setting signal s 102 is calculated, and a supply liquid flow rate deviation signal 5103 is output to the alarm setting device 104 and the signal switching device 105. On the other hand, the reference numeral 106 in the figure is a head tank liquid level detector, and the reference numeral 107 is a function generator. The head tank liquid level detector 106 detects the liquid level in the head tank 8, and also functions as a function generator 1.
07 outputs a function as shown in FIG.

FIG. 3 is a diagram showing time changes in the head tank liquid level, with time on the horizontal axis and head tank liquid level on the vertical axis. In this case as well, the liquid level is increased linearly until the target liquid level (Hl) is reached, and then that state is maintained. Both the head tank liquid level detection signal 5106 from the head tank liquid level detector 106 and the head tank liquid level setting signal s 107 from the function generator 107 are input to the head tank liquid level deviation calculator 108. This head tank liquid level deviation calculator 108 calculates the deviation between the two signals and outputs a head tank liquid level deviation signal s 108 to the signal switch 105.

Further, a switching signal s 104 is outputted from the alarm setting device 104 to the signal switching device 105 . The signal switch 105 switches between the supply liquid flow rate deviation signal s 103 and the head tank liquid level deviation signal 5108 in response to the switching signal 5104 from the alarm setting device 104. Specifically, during normal times, the liquid supply flow rate is controlled based on the liquid supply flow rate deviation signal 5103, and when an abnormality occurs in the liquid supply flow rate detector 101,
This is detected by the alarm setting device 104 and the switching signal s
104 is output to the signal switch 105 to switch to control of the liquid supply flow using the head tank liquid level deviation signal 5108.

This takes advantage of the fact that the liquid level in the head tank 8 and the liquid supply flow rate have a fixed relationship in principle, and is possible by setting the liquid level corresponding to the normal liquid supply flow rate in advance. (This is the head tank liquid level setting signal 510
7). From the signal switch 105 to the valve opening regulator 1
09, 5105 (either the flow rate deviation signal s 103 or the head tank liquid level deviation signal 5107) is output.

Valve opening adjustment:=109 outputs a valve opening adjustment signal 5109 to the flow rate regulating valve 10 so that the deviation becomes zero based on this signal 5105.

The operation will be explained based on the above configuration. First, when the liquid supply start signal is output, the deviation between the liquid supply flow rate setting signal s 102 from the function generator 102 and the liquid supply flow rate detection signal s 101 from the liquid supply flow rate detector 101 is the liquid supply flow rate deviation signal. s
As 103, the supplied liquid flow rate deviation calculator 103 outputs the signal to the valve opening controller 109 via the signal switch 105, and the opening of the flow rate control valve 10 is controlled. The control at this time is the same as that shown in FIG. Meanwhile, at the same time, the head tank liquid level deviation calculator 108 receives a head tank liquid level setting signal 5 corresponding to the liquid supply flow rate setting signal from the function generator 107.
107 is input. Further, the head tank liquid level detection signal s10B from the head tank liquid level detector 06 is also input manually to the head tank liquid level deviation calculator 108.

The head tank liquid level deviation calculator 108 calculates the deviation between these two signals and outputs it to the signal switch 105 as a head tank liquid level deviation signal s108. Normally, the signal switch 105 selects the supplied liquid flow rate deviation signal s 103 from the supplied liquid flow rate deviation calculator 103, and the flow rate is controlled as described above. When the supplied liquid flow rate deviation signal s 103 becomes larger than a preset value (specifically, when normal flow rate detection is impossible due to pipe blockage of the supplied liquid flow rate detector 101, etc.), the alarm setting device 10
4 is activated and outputs the switching signal s 104 to the signal switching device 105. The output of the switching signal 5104 causes the signal switching device 105 to operate and switch to the head tank liquid level deviation signal 8108 from the head tank liquid level deviation calculator 108. This prevents fluctuations in the liquid supply flow rate due to abnormalities in the liquid supply flow rate detector 101 and various problems caused by the fluctuations. In this way, normally, the supply liquid flow rate is controlled by feedback control based on the supply liquid flow rate deviation signal 5103. When the supplied liquid flow rate deviation signal s 103 becomes larger than a predetermined value, this is detected by the alarm setting device 104 and switched to the head tank liquid level deviation signal 3108 side via the signal switch 105. The liquid supply flow rate is controlled by the signal 5108.

According to this embodiment, the following effects can be achieved. That is, the alarm setting device 104 detects the disturbance of the flow rate detection signal s 101 from the flow rate detector 101 and the resulting disturbance of the flow rate deviation signal 5103, and the head tank liquid level deviation signal s is determined from the control based on the supply liquid flow rate deviation signal s 103. Based on 108 (because the system switches to liquid supply flow rate control, the liquid supply flow rate detector 101, which was a concern in the past)
It is possible to effectively prevent disturbances in the liquid supply flow rate signal s101 due to air being mixed into the liquid supply flow rate signal s101, and disturbances in the liquid supply flow rate due to this.

In this way, it is possible to prevent disturbances in the supply fluid flow rate, thereby preventing an increase in the load on the motor 2 of the centrifugal thin film dryer 1, as well as preventing unnecessary trips and providing stable operation. , the powder properties can be improved.

It should be noted that the present invention is not limited to the one embodiment described above, and various configurations can be considered for detecting abnormalities in the liquid supply flow rate detector.

[Effects of the Invention] As detailed above, according to the liquid supply flow rate control device for a centrifugal thin film dryer according to the present invention, stable liquid supply flow rate control can be performed even when an abnormality occurs in the flow rate detector. This makes it possible to reliably prevent various problems caused by fluctuations in the fluid supply flow rate.

[Brief explanation of the drawing]

Figures 1 to 3 are diagrams showing one embodiment of the present invention.
The figure is a configuration diagram of the liquid supply flow rate control device, Figure 2 is a characteristic diagram showing the time change of the liquid supply flow rate, Figure 3 is a characteristic diagram showing the time change of the head tank liquid level, and Figure 4 is a centrifugal thin film dryer. It is a block diagram of the powderization equipment of radioactive waste liquid using. 1... Centrifugal thin film dryer, 5... Waste liquid supply tank, 8
...Head tank, 10...Flow 2 control valve, 11...
- Liquid supply piping, 101... Flow rate detector, 102... Function generator, 103... Liquid supply flow rate deviation calculator, 104.
...Alarm setting device, 105...Signal switch, 106...
・Head tank liquid level detector, 107...Function generator,
108...Head tank liquid level deviation calculator, 109...
・Valve opening adjuster. Applicant's agent Patent attorney Takehiko Suzue 22 Figure 3

Claims (2)

[Claims] (1) A liquid supply flow rate detector attached to the liquid supply pipe installed between the head tank and the centrifugal thin film dryer, and a liquid supply flow rate detection signal from this liquid supply flow rate detector set in advance. a supply liquid flow rate deviation calculator that compares the supplied liquid flow rate setting signal and outputs the deviation as a supply liquid flow rate deviation signal to a signal switching device;
The head tank liquid level detector detects the liquid level in the head tank, and the head tank liquid level detection signal from this head tank liquid level detector is compared with a preset head tank liquid level setting signal to detect the head tank liquid level. a head tank liquid level deviation calculator that outputs a liquid level deviation signal to the signal switch; and a head tank liquid level deviation calculator that outputs a liquid level deviation signal to the signal switch; and a head tank liquid level deviation calculator that outputs a liquid level deviation signal to the signal switch; A valve opening controller that adjusts the opening of a flow rate control valve inserted in the processing liquid stirring line, and a supply liquid flow rate deviation signal from the liquid supply flow rate deviation calculator are input to the liquid supply flow rate detector. It is determined whether an abnormality has occurred, and if it is determined that an abnormality has occurred, a switching signal is output to the signal switching device, and the liquid supply flow rate control is changed from liquid supply flow rate control based on the liquid supply flow rate deviation signal to liquid supply based on the head tank liquid level deviation signal. A liquid supply flow rate control device for a centrifugal thin film dryer, characterized by comprising an alarm setting device for switching to flow rate control. (2) The above-mentioned alarm setting device determines that an abnormality has occurred in the liquid supply flow rate detector when the liquid supply flow rate deviation signal exceeds a preset value. 2. A liquid supply flow rate control device for a centrifugal thin film dryer according to item 1.