JPH0238719B2 - SHOSHIKISEIGYOSOCHI - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention relates to an improvement in the control system of automatic papermaking speed change control and automatic papermaking change control of a paper machine having a decululator (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 raw material flow rate sensor and Q is its measured value, 3 is a seed port valve, and the raw material with a concentration of about 3% supplied from this seed port valve is 1 It is mixed with the low-concentration white water W from the silo 5 at the suction port of the secondary fan pump 4, and is diluted, stirred, and pumped by the primary fan pump.

The low-concentration raw materials (approximately 0.3% to 1.0%) pumped from the primary fan pump are carefully selected by Beaugeect 6.
Dust is removed and the air is degassed by a decululator 7. The raw material that has passed through the decululator is pumped by a secondary pump 8,
It is further selected and dusted 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 press 13, dried by a dryer 14, and wound onto a reel 15.
Return raw material R of decululator 7 and wire 14
The dehydrated S is returned to the silo 5.

16 is 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 PV, the calculating means 17 generates the absolute dry basis weight signal BD and the moisture content signal MP. Calculated.

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

Reference numeral 20 denotes a control device, which displays measured values at various locations, seed opening flow rate F, bone dry basis weight signal BD, moisture content signal MP, press/dryer machine speed V, wire machine speed V _W , bone dry basis weight setting value BD Input _S and set the operation amount Q to seed port valve 3 by 2.
Next, apply the operation amount H to the fan pump, and the controller 18
The machine speed setting operation output V _S is supplied to the dryer 14, and the steam pressure setting operation output P _S 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 papermaking speed change control and automatic papermaking change control will be explained.

(1) Automatic machine speed change control is a control that changes only the machine 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 adjusted by the inlet pressure (total head).

(2) Automatic paper change control is control that changes basis weight, moisture content, machine speed, and jet wire ratio from state A to state B in the shortest possible time.

(3) In automatic papermaking speed change control and automatic papermaking change control, the following operating variables after change are calculated from the mass balance of the paper machine and the drying balance of the dryer, and dynamic compensation is applied that takes into account the mass balance at the inlet. In addition, it is operated.

<Manipulated variable> Seed opening flow rate The manipulated variable Q is a function of bone dry basis weight BD and machine speed V, and is expressed as Q=f(BD, V), and the operating end is the seed opening valve.

Steam pressure Setting value of the steam pressure controller in the dryer P _S
The manipulated variable P _S is the absolute dry basis weight.
It is a function of BD, machine speed V, and moisture content MP, and is expressed as P _S =g (BD, V, MP).

Machine speed Operated by changing the output of the set value V _S to the machine speed controller.

The total head operation amount H is a function of the jet wire ratio J/W and the wire speed _VW , and is expressed as H=h(J/W, _VW ), and the operation end is a secondary fan pump or a stream flow valve. .

(4) From the moment the machine speed is started, the seed opening valve is operated so that the inlet concentration changes along the trajectory given by _BDS .

When operating the seed opening valve, take into account the change in inlet concentration due to total head operation and the dead time until the concentration change.

Dynamic compensation when the total head is raised while the seed opening valve 3 is maintained at a constant opening will be described below.

4.1...Increase the discharge flow rate 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 amount R of the deculator is reduced.

4.3...Since the over-return amount of the deculator returning to silo 5 decreases, the white water concentration in the silo decreases. Therefore, the concentration at the outlet of the primary fan pump decreases, and it reaches the inlet 11 through the Voject 6, the deculator 7, the secondary fan pump 8, and the screen 9.

4.4...Compared to the transportation delay time due to capacity from the primary fan pump to the inlet, 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 the concentration inside the silo basically changes due to sedimentation.

4.5... Therefore, so-called dynamic compensation is required to change the inlet concentration by operating the seed opening valve 3 from the time when the machine speed operation, that is, the total head operation is started, until the inlet concentration changes. Become.

<Problems to be Solved by the Invention> As described above, in the automatic paper speed change control and automatic paper change control of a paper machine having a decululator, when the total head operation is performed by the secondary fan pump, the total head operation Since the dead time between the inlet concentration and the inlet concentration changes is extremely long, about 4 to 5 minutes, it takes a long time to change the inlet concentration.If dynamic compensation is not appropriate, it will take a long time to make defective products, and the controllability will decrease. There are some problems, such as that it is not very good.

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

<Means for Solving the Problems> The structural feature of the present invention is that the raw material provided from the seed opening valve and the white water from the silo are pumped to the decululator by the primary fan pump, and the raw material that has passed through the decululator is transferred to the decululator. Next, in a paper machine configured to pressure feed raw material with a fan pump, guide it to an inlet via a stream flow valve, and discharge the raw material onto a wire from the inlet, the total head of the inlet can be changed to perform automatic paper speed change control or automatic paper change. When controlling, the total head is adjusted based on the feed forward control means that controls the rotation speed of the secondary fan pump or the opening degree of the stream flow valve, and the total head sensor output and the total head set value. a feedback control means for controlling the return amount of the secondary fan pump or the bypass amount of the stream flow valve; and controlling the inlet concentration accompanying the total head adjustment by manipulating the rotational speed of the primary fan pump. The present invention also includes a feed forward control means for controlling the feed forward.

<Function> According to the present invention, the total head is adjusted by performing feedforward operation (coarse adjustment) of the secondary fan pump rotation speed (or stream flow valve opening) from the control device, and if it deviates, This is done by controlling the return amount of the secondary fan pump (or the bypass amount of the stream flow valve) using a feedback loop (fine adjustment) using a total head controller configured as a local loop.

When the inlet concentration changes due to total head adjustment, the control device outputs an 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 over-return amount of the decululator constant. Accordingly, 1
This is then produced by the concentration change at the outlet of the fan pump.

<Example> An example of the present invention will be described 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 setter that sets the pressure using air pressure based on the total head setting operation output H from the control device 20, and 23 is a head sensor/deviation transmitter for the inlet 11, which adjusts the total head by adjusting the deviation between the measuring head and the setting head. A total of 24 calls will be made. This controller executes feedback control to bring the total head into line by operating 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 return valve 4' of the primary fan pump based on the deviation between the measured value of the level sensor 26 and the level set value L.
Adjust the opening to maintain a constant level.
This controller is an adjunct to feedforward control for the primary fan pump.

27 is a steam pressure controller, and a pressure sensor 28
The valve opening degree of the steam flow rate control valve 29 is adjusted based on the deviation between the measured value and the steam pressure setting operation output V _p .

The characteristic control in the present invention is to control the operation output M ₂ for executing feed forward control for the secondary fan pump 8 and the operation output M ₁ for executing feed forward control for the primary fan pump. The point is that the device 20 sends a message.

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.

Seed port valve operating output...Q Total head setting operating output...H Primary fan pump operating output...M ₁ Secondary fan pump operating output...M ₂ Machine speed setting operating output...V _s Steam pressure setting operating output...V _p2nd The figure is a flowchart explaining the overall control flow, including operation of the seed opening valve, operation of the steam pressure,
It consists of three systems: machine speed and total head operation, and after each system is controlled with dynamic compensation in mind, an error check and a termination condition check are performed, and after a timer of about 10 seconds has elapsed. Control is executed for the next operation cycle, and when the termination condition is satisfied, the control is terminated.

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

(1) Calculate the total head setting value H _i from the current machine speed setting value V _i and the target jet wire ratio setting value α _i as follows.

H _i =h (V _i , α _i ) (2) Next, find the difference ΔH _i from the current total head setting feedback value _HF .

ΔH _i =H _i −H _F (3) At the same time as ΔH _i is output to the total head setting device 22, the following operation outputs are output to the secondary fan pump and the primary fan pump, respectively.

M _2i = ΔH _i /K _M2 M _1i = ΔH _i・K _L ^* /K _L where, K _M2 : Amount of change in total head when the secondary fan pump is operated by a unit amount K _L ^* : Total head is the unit Amount of change in the decululator level when the amount changes _KL : Amount of change in the deculator level when the primary fan pump is operated by a unit amount.

The manipulated variables M _2i and M _1i are feedforward manipulated variables to the secondary fan pump 8 and the primary fan pump 4. Therefore, it may deviate from the optimum value, but if it deviates, the total head controller 2, which forms a local feedback control loop,
4. The level controller 25 is activated and a process for immediately correcting the level to the optimum value is executed.

In the above embodiment, a secondary fan pump is used as the operating end of the feedback 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 the bypass valve 10' instead of using the secondary fan pump. . Furthermore, the feed forward 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 decululator can be performed by: (2) Furthermore, in order to keep the amount of over-return of the deculator constant, the rotation speed of the primary fan pump can be adjusted as necessary. Since a feedback operation is performed by the added level controller, changes in inlet concentration due to total head adjustment are created by changes in concentration at the outlet of the primary fan pump, so that 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 within the silo, which will take a long time.

Therefore, by performing the operation of the present invention using (1) and (2) in combination, the dead time until the inlet concentration changes due to total head operation can be shortened, and the time required for change and control can be shortened. It can be expected to improve sexual performance.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention, FIG. 2 is a flowchart explaining the overall flow of control,
FIG. 3 is a configuration diagram showing an example of the prior art. 1... Seed port pipe line, 2... Seed port flow rate sensor, 3... Seed port valve, 4... Primary fan pump, 5... Silo, 6...
Beauject, 7... Deculator, 8... Secondary fan pump, 10... Streamflow valve, 11... Inlet, 12... Wire, 13... Press, 14...
Dryer, 15...Reel, 16...B/M total, 17
...Arithmetic means, 18...Controller, 20...Control device, 21...Man-machine interface, 22...
Total head setting device, 23...Head sensor,
24...Total head controller, 25...Level controller.

Claims (1)

[Scope of Claims] 1. The raw material supplied from the seed port valve and the white water from the silo are pumped to a decululator by a primary fan pump, and the raw material that has passed through the decululator is pumped by a secondary fan pump to be passed through a stream flow valve. In a paper machine configured to introduce raw material into an inlet and discharge it onto a wire from the inlet, when changing the total head of the inlet to perform automatic paper speed change control or automatic paper type change control,
Feedforward means adjusts the total head by manipulating the rotational speed of the secondary fan pump or the opening degree of the stream flow valve; Feedback means for manipulating the return amount of the pump or bypass amount of the stream flow valve; Feedback means for controlling the inlet concentration in accordance with the total head adjustment by manipulating the rotational speed of the primary fan pump. A paper machine control device consisting of: