JPS62199890A - Apparatus for controlling papermaking machine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention relates to an improvement in the control system of automatic paper speed change control and automatic paper change control of a paper machine having a deculator (deaerator).

<Prior Art> An overview of general control of a paper machine having a deculator will be explained based on FIG. 1 is a seed port pipe through which raw material A is supplied, 2 is a flow rate sensor for the raw material and Q is its measured value, 3 is a seed port valve, and the material at a temperature of about 3% supplied from this seed port valve is It mixes with the low concentration white water W from the silo 5 at the suction port of the primary fan pump 4, and is diluted by the primary fan pump, W! Stirred and pumped.

Low concentration raw material (0.3%) pumped from the primary fan pump
~1.0%) is carefully selected and dust removed by a Beaugeect 6, and degassed by a deculator 7. The raw material that has passed through the deculator is pumped by a secondary pump 8, further selected and dust-removed by a screen 9, and then enters an inlet 11.

The raw material discharged from the inlet is dehydrated by a wire 12, then squeezed by a breather 13, dried by a dryer 14, and wound onto a reel 15.

The return material R of the deculator 7 and the dehydrated S of the wire 14 are returned to the silo 5.

Reference numeral 16 denotes a sensor (hereinafter referred to as a B/M meter) for measuring the absolute dry basis weight and moisture content of the product, and based on the measurement output P, a calculation means 17 generates an absolute dry basis weight signal BD and a moisture content signal MP. is calculated.

18 is press 13. A controller 19 controls the speed per second of the dryer 14, and a controller 19 further controls the speed per second of the wire 12 based on the output of this controller.

2o is a control device, which controls the measured values at various places, the seed mouth flow ff1F
, absolute dry tsubo m signal BO9 moisture content signal MP, press/dryer machine speed ■, wire paper speed V The operation fiH, the machine speed setting operation output VS is supplied to the controller 18, and the steam pressure setting operation output Ps is supplied to the dryer 14, respectively. 21 is a man-machine interface means for exchanging information with the control device 20;

In such a basic configuration, conventional automatic paper speed change control,
Automatic paper change control will be explained.

(1) Automatic papermaking speed change control is control that changes only the papermaking speed while keeping the basis weight, moisture content, and jet wire ratio constant. Here, the jet wire ratio is the ratio of the raw material discharge speed from the inlet to the wire speed, and the raw material discharge speed is WAm determined by the inlet pressure (total head).

(2) Automatic paper change control means tsubo, moisture content, and paper speed.

This control changes the jet wire ratio from state A to state B in the shortest possible time.

(3) In automatic speed-per-second change control and automatic paper type change control, the following operating variables after change are calculated based on the paper machine mass balance and the dryer drying balance, and dynamic compensation is added that takes into account the mass balance at the inlet. is being operated.

<Manipulated variables> ■ Seed opening flow rate operation ff1Q is a function of absolute dry area ff1BD and papermaking speed ■,
It is expressed as Q-/(BD, V), and the operating end is a seed opening valve.

■It is operated by changing the set value Ps of the steam pressure controller that controls the steam pressure dryer, and the operating pressure Ps is a function of the absolute dry area ff1BD, paper speed ■, and moisture content MP, Ps −'J (80, V, MP).

■ Machine speed It is operated by changing the output of set value v5 to the machine speed controller.

■Total head operation amount 1" is the jet wire ratio J/
As a function of W and wire speed Vu+, t1-1 (J/W
, Vw), and the operating end is a secondary fan pump or a stream flow valve.

(4) From the moment you start operating the machine speed, the inlet
5 Operate the seed mouth valve so that it changes along the trajectory given by B D s.

When operating the seed opening valve, take into account the inlet concentration change due to total head operation and the dead time until the concentration change. □Hereinafter, a description will be given of dynamic compensation when the total head is raised while the seed opening valve 3 is maintained at a constant opening.

4.1...Increase the discharge flow from the secondary fan pump to increase the total head.

4.2...Since the discharge flow rate from the primary fan pump is constant, the over-return ff1R of the deculator is reduced.

4.3...Since the over-return amount of the deculator returning to silo 5 is reduced, the white water of the silo) Rfffi
goes down. Therefore, the 8i1 degree at the primary fan pump outlet decreases, which causes the bow jet 6. Deculator 7° Secondary fan pump 8. It passes through the screen 9 and reaches the inlet 11.

4.4...Capacity a from primary fan pump to inlet
Compared to the transport delay time caused by the silo, the dead time until the white water concentration in the silo changes is incomparably large.

This is because the capacity of the silo is quite large, and without a silo, the concentration would basically change due to sedimentation.

4.5... Therefore, from the time when the machine speed operation, that is, the operation of the total head is started, until the inlet concentration changes, the seed opening valve 3 is operated to change the inlet concentration, so-called dynamic operation. Compensation will be required.

<Problems to be Solved by the Invention> As described above, in the automatic paper speed change control 1 automatic paper change I11 control of a paper machine having a deculator, when the total head operation is performed by the secondary fan pump, the total head The dead time from operation until the inlet 11 degrees changes is extremely long, about 4 to 5 minutes, which increases the time required for change. Therefore, if dynamic compensation is not appropriate, it takes a long time to make defective products, and control Sex is also not very good,
There are problems such as:

It is an object of the present invention to provide a control device that solves these problems, shortens the waste time 84, and improves the time required for changes and controllability.

Means for Solving the Problems> The structural features of the present invention are that the raw material supplied from the seed port valve and the white water from the silo are pumped to the deculator by the primary fan pump, and the raw material that has passed through the deculator is Next, in a paper machine configured to force feed raw materials with a fan pump, guide them to an inlet via a stream flow valve, and discharge the raw materials onto a wire from the inlet, the total head of the inlet can be changed to automatically change the papermaking speed υ Jail or automatic When changing the papermaking speed, a feedforward control means is used to control the am of the total head by manipulating the rotational speed of the secondary fan pump or the opening degree of the stream flow valve, and a total head sensor output and a total head setting value are used. feedback control means for controlling the return amount of the secondary fan pump or the bypass of the stream flow valve; The present invention is equipped with feedforward control means that controls the rotational speed and the opening degree of the return valve.

According to the present invention, the total head is adjusted by feedforward operation (coarse adjustment) of the secondary fan pump rotation speed (or stream 70 - valve distance) from the control device, and if it deviates, the local loop The secondary fan pump return ff1 (or stream 70-
This is done by operating the valve (bypass collapse).

In response to changes in inlet concentration due to total head adjustment, the control device applies operational output to the primary fan pump (or the primary fan pump and the return valve of the primary fan pump) in order to keep the A-bar return amount of the deculator constant. is produced by a degree change in the outlet of the primary fan pump.

<Example> The present invention will be explained in detail based on FIG. Components that are the same as those explained in FIG. 3 are given the same reference numerals, and the explanation thereof will be omitted.

22 is a total head setting device that sets the pressure using pneumatic pressure based on the total head setting operation output H from the control device Wi 20, and 23 is a head sensor and width difference transmitter of the inlet 11, which detects the deviation between the measuring head and the setting head as a total head setting device. The signal is transmitted to the controller 24. This controller executes feedback control to adjust the return valve 8' of the secondary fan pump when the total head deviates from the set value.

Reference numeral 25 denotes a level controller of the deculator, which adjusts the opening degree of the return valve 4' of the primary fan pump based on the deviation between the measured value of the level sensor 26 and the level setting 1aL to maintain the level constant.

This controller is an adjunct to feedforward control for the primary fan pump.

A steam pressure regulator 27 adjusts the opening degree of the steam flow rate control valve 29 based on the deviation between the measured value of the pressure sensor 28 and the steam pressure setting operation output Vp.

The characteristic control in the present invention is to transmit from the control device 20 an operation output M2 for executing feedforward control for the secondary fan pump 8 and an operation output M+ for executing feedforward control for the primary fan pump. At the point.

Next, the operation will be explained. First, the target values of basis weight, moisture content, paper speed, and jet wire ratio after paper change or paper speed change are entered into the control device 20 from the screen of the man-machine interface 21. When an execution command is issued, the next operating output is calculated from the mass balance and drying balance, dynamic compensation is added, and the operating end is controlled.

Hard valve operating output...Q Total head setting operating output...H Primary fan pump operating output...M1 Secondary fan pump operating output...M2 Machine speed setting operating output...Vs Steam pressure setting Operation output...Vp Figure 3 is a flowchart explaining the overall control flow, including operation of the seed port valve and operation of the steam pressure.

It consists of three systems: speed per second and total head operation, and after each system executes control that takes into account dynamic compensation, an error check and a termination condition check are performed, and the time is 4S in about 10 seconds!
The control for the next operation cycle is executed after the time elapses using the timer, and the control ends when the termination condition is satisfied.

Next, specific steps for operating the total head for automatic paper speed change control and automatic paper change control, which are related to the subject matter of the present invention, will be described.

(1) Calculate the total head setting value Ht from the current speed per second setting value Vi and the jet wire ratio target setting value α1 as follows.

HL=h, (VL, α,) (2) Next, the current total head setting feedback l
+tl Find the difference Δl-1t from Hp.

ΔHt −Ht −HF (3) At the same time as outputting ΔHt to the total head setting device 22, the following operation outputs are sent to the secondary fan pump, 1, respectively.
Output to the next fan pump.

M2(-ΔHt / KM 2 M+i -ΔH(・KL"/KL Where, KM2: Amount of change in the total head when the secondary fan pump is operated by a unit amount KL") Data when the total head changes by a unit amount Amount of change in curator level KL: This is the amount of change in deculator level when the primary fan pump is operated by a unit amount.

Operation mM2i, M+t is a feedforward operation m from the secondary fan pump 8° to the primary fan pump 4.

Therefore, the total head controller 24 may deviate from the optimum value, but if it deviates, it forms a local feedback control loop. The level controller 25 is activated and a process for immediately correcting the level to the optimum value is executed.
- In the above embodiment, the secondary fan pump is used as the operating end of the feedforward and feedback control.

Although an example has been shown in which the primary fan pump and their return valves are operated, similar control results can be obtained by controlling the stream flow valve 10 and bypass valve 10' instead of using the secondary fan pump. I can do it. Furthermore, the feedforward operation of the primary fan pump may be performed by simultaneously operating the rotation speed and the return valve.

Further, the level controller 25 for adjusting the level of the deculator can be omitted.

<Effects of the Invention> As explained above, according to the present invention, automatic paper speed change control and automatic paper change control of a paper machine having a deculator can be performed by: (1) Total head adjustment is performed by adjusting the rotation speed of the secondary fan pump (2) Feedforward operation of the rotation speed of the primary fan pump and additional control as necessary to keep the overreturn amount of the deculator roughly constant. Since the feedback operation is performed by the level adjustment z1, the change in inlet IHjI due to the total head adjustment is created by the m degree change at the primary fan pump outlet, so the dead time element passing through silo 5 is This makes it possible to achieve the highest level of control.

If such feedforward control of the primary fan pump does not exist, changes in inlet concentration will result in changes in white water concentration in the silo, which will take a long time.

Therefore, by performing the operation of the present invention in combination with (1) and (2>), it is possible to shorten the dead time until the inlet concentration changes due to total head operation, and improve the time required for change and controllability. can be expected.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an actual example of the present invention, FIG. 2 is a flowchart explaining the overall flow of control, and FIG. 3 is a block diagram showing an example of the prior art. 1... Seed port pipe 2... Seed port flow threat sensor 3
...Seed port valve 4...Primary fan pump 5...
・Silo 6... Beaugeect 7... Deculator 8... Secondary fan pump 10... Stream flow valve 11... Inlet 12... Wire 3... Press 14... Dryer -5.
... Reel 16... B/M meter 17... Calculating means 18... Control [1-ra 20... Control ll
Device 21...Man-machine interface 2
2...Total head setting device 23...Head sensor 24...Total head controller 25.
・Level controller

Claims (1)

[Claims] The raw material supplied from the seed port valve and the white water from the silo are pumped to the deculator by the primary fan pump, and the raw material that has passed through the decululator is pumped by the secondary fan pump, guided to the inlet via the stream flow valve, and from the inlet. In a paper machine configured to discharge raw materials onto a wire, when changing the total head of the inlet to perform automatic paper speed change control or automatic paper change control, the total head is adjusted by changing the rotation speed of the secondary fan pump or Feed forward control means that operates the opening degree of the stream flow valve, and controls the return amount of the secondary fan pump or the bypass amount of the stream flow valve based on the total head sensor output and the total head setting value. A paper machine comprising a feedback control means and a feedforward control means for controlling the inlet concentration in accordance with the total head adjustment by manipulating the rotation speed of the primary fan pump or the rotation speed and the opening degree of the return valve. Control device.