JPS5932591B2 - Refiner control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a refiner control device that improves paper quality in a papermaking process.

In the paper manufacturing process, freeness is one element that determines the quality of paper.

Freeness refers to the degree of entanglement of fibers in pulp liquid, which is the raw material for paper, and is important for paper strength, printability, and suitability for secondary processing.

The test method for this freeness is defined in JISP-8121, and the freeness is defined as the amount of water removed from the sieve plate by the pulp liquid placed in the filter tube.

Furthermore, since the freeness is determined by the degree of freeness in the refiner, control of the refiner is usually carried out by controlling the degree of freedom.

Figure 1 shows a system diagram of this conventional glue finer control.
Further, FIG. 2 shows the configuration of a conventional glue finer control device.

When the production volume of the refiner is constant, the degree of beating is normally proportional to the power consumption for beating, and the input power of the drive motor 12 that drives the refiner 11 is measured by the power detector 15, and the power control so that it remains constant.

Here, 13 is a gap adjustment motor, 14 is a freeness setting device, 16 is a controller, and 17 is a gap adjustment control device.

Taking a disc refiner as an example, the freeness is controlled by adjusting the gap between the fixed disc and the movable disc.

That is, when the driving power decreases, the degree of beating decreases, so the operating motor attached to the movable disk is operated in the direction of decreasing the gap.

On the other hand, when the driving power increases, the gap is increased.

In FIG. 2, when the freeness setting value is inputted to the controller 16 from the freeness setting circuit 14, the set power calculation circuit 18 calculates the set power using a linear equation since it is assumed that the power is proportional to the beating # (freeness). Ru.

On the other hand, the input power of the drive motor 12 that drives the refiner 11 is measured by the power detector 15, and the measured power is compared with the set power.

Then, the gap adjustment control device 17 calculates the gap operation amount via the control algorithm 19 according to the deviation amount.
By giving an operational output to the refiner 11 and controlling the beating degree of the refiner 11, the freeness is controlled to the set value.

In this way, with conventional equipment, the energy (power) consumed for beating changes depending on the fluctuations in the concentration, flow rate, and temperature of the pulp liquid passing through the refiner. It could not be called control, had major drawbacks in terms of accuracy, and had a large impact on the quality of paper products.

The present invention has been made based on the above reasons and aims to improve the quality of paper.

It is an object of the present invention to provide a control device for a refiner that does not have the above-mentioned drawbacks.

The present invention will be described below based on an embodiment shown in the drawings.

FIG. 3 shows a system diagram of the present invention.

In this system, a digital control device 25 composed of an electronic computer or the like is newly added in place of the controller 16 in the system diagram shown in FIG.

That is, the digital control device 25 is configured to be connected to various detectors such as a freeness detector 21, a concentration detector 22, a flow rate detector 23, a temperature detector 24, etc., and to receive each detection signal.

The main control loop of the system measures the input power of the drive motor 12 that drives the refiner 11 with a power detector 15, similar to conventional glue refiner controllers.

Then, the rotation speed of the gap adjustment motor 13 is controlled via the gap adjustment control device 17 so that the electric power is constant, thereby adjusting the gap.

However, with this control loop alone, the freeness will fluctuate due to fluctuations in the concentration, flow rate, and temperature of the pulp liquid passing through the refiner. High-precision calculation and measurement of freeness is performed from each of the 24 signal elements.

Next, this measured value is compared with the set freeness input from the freeness setting circuit 14 to adjust the gap.

FIG. 4 shows the configuration of the refiner control device of the present invention.

In the same figure, the freeness is. The freeness setting circuit 14 inputs the signal to the digital control device 25, and the set power calculation circuit 18 calculates the set power.

At this time, the electric power is proportional to the freeness, so it can be determined by a linear equation.

Next, as for the actual power, the power detector 15 detects the input power of the drive motor 12 that drives the refiner 11, and this detected value is input to the digital control device 25.

Then, at a constant sample synchronization 'r1, the amount of deviation from the set power is calculated and sent to the control algorithm 31, where the gap operation amount for making the amount of deviation zero is calculated.

This calculated value is output to the gap adjustment control device 17 via the zero-order hold circuit 33 at a constant output cycle T2, and drives the gap adjustment motor to adjust the gap between the disks.

On the other hand, the freeness value detected from the outlet side of the refiner 11 is input to the digital control device 25 via the freeness detection circuit 29.

Similarly, the flow rate, concentration, and temperature of the pulp liquid passing through the refiner 11 are also detected by the digital control device 2 via a flow rate detection circuit 26, a concentration detection circuit 27, and a temperature detection circuit 28, respectively.
5 is input.

Then, using the following calculation formula, the freeness correction calculation circuit 34
A high-precision correction calculation of the actual freeness value is performed at a constant sampling period.

Ff”k□+, 1”F+, 2”M+, 3・C0,・T
(1) Here, Ff is freeness after correction, F is measured freeness, M is flow rate, C is degrees, T is temperature, ko.

kl, 2. 3. 4 is a coefficient.

The output value of the freeness correction calculation circuit 34 is compared with the freeness setting value set by the freeness setting circuit 14 at a constant sampling period T3, and the deviation amount is inputted to the control algorithm 32.

Then, the gap operation amount to make the deviation amount zero is calculated, and at a constant output synchronization T4, it is output to the gap adjustment control device 1γ via the zero-order hold circuit 33, and drives the gap adjustment motor to adjust the disc degree. Adjust the gap.

Here, the sampling period T3 and the output period T4 are the dynamic characteristics of the process and the sampling period T of the main control loop.
This is uniquely determined by one output period T2.

In this manner, the present invention can provide an effective finer control device that is not affected by fluctuations in pulp concentration, pulp flow rate, and pulp temperature and can perform highly accurate control.

[Brief explanation of drawings]

Fig. 1 is a system diagram of conventional glue finer control, Fig. 2 hl
A block diagram showing the configuration of a conventional glue finer control device,
FIG. 3 is a refiner control system diagram showing one embodiment of the present invention, and FIG. 4 is a hook diagram showing the configuration of the refiner control device. 11... Refiner, 12... Drive morph, 13... Gear knob adjustment morph, 1
4... Freeness setting device, 15... Power detector, 16... Controller, 1T...
... Gap adjustment control device, 18 ... Setting power calculation circuit, 19 ... Control algorithm, 2
1... Freeness detector, 22... Concentration detector, 23... Flow rate detector, 24...
...Temperature detector, 25...Digital control device, 26...Flow rate detection circuit, 2γ...Concentration detection circuit, 28...Temperature detection circuit, 29...
...Freeness detection circuit, 31... Control algorithm, 32... Control algorithm, 33
...0th order hold circuit, 34...Freeness correction calculation circuit.

Claims (1)

[Claims] 1. In a refiner control device that is equipped with a constant power control loop for the papermaking process, each detector installed on the outlet side of the refiner detects freeness, concentration, flow rate, and temperature, and the detection output of this detector. Digital control that inputs and substitutes into a mathematical model to perform freeness correction calculations, compares this calculated value with a set value, and calculates the gap operation amount between the fixed desk and movable disk of the refiner according to the deviation between the two. and a gap adjustment control device for adjusting the gap between the disks by inputting the output of the digital can 1j control device, and controlling the freeness to a constant level.
control device.