JPS5911128B2 - Method for controlling the amount of glue added at a constant concentration - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling the amount of a sizing agent added at a constant concentration, which is carried out, for example, when adding 10 sizing agents to paper raw materials in a paper manufacturing process.

Conventionally, the viscosity of the mixture 15 after addition of the sizing agent is maintained constant in a sizing agent addition device equipped with an additive material transporting pipe and a sizing agent transporting pipe that merges with this pipe and has a flow rate control valve in the middle. It was quite difficult.

The main reasons for this are that even if the sizing agent has a constant concentration, its viscosity changes depending on the temperature, and the flow rate of the additive flowing through the additive transport pipe changes from moment to moment. An object of the present invention is to eliminate the above-mentioned drawbacks, measure changes in the flow rate and temperature of the material to be added, automatically change the flow rate of the sizing agent accordingly, and add the sizing agent. It is an object of the present invention to provide a method for controlling the amount of a sizing agent added at a constant concentration by which the viscosity of a subsequent mixture can be kept constant.

As a result of extensive research to achieve the above object, the inventors devised the following points.

First, it is generally known that the relationship between the viscosity M of the glue and the temperature of the glue is expressed by the following equation. 30ri=C2e
-a・・・・・・・・・・・・・・・(I) However, C2
■Constant determined by the properties of the glue, a2Constant determined by the properties of the glue. The value of the slope with a negative sign, is: the temperature of the glue.

In addition, in general, for paper raw materials, etc., in order to keep the viscosity of the mixture constant after adding a sizing agent, the viscosity (7) can be lowered by increasing the addition rate (γ), whereas the viscosity (7) can be lowered by increasing the viscosity. The addition rate (γ) may be small, so the addition rate (γ
) and viscosity M are inversely proportional.

This can be expressed as a formula as follows. However, V: viscosity of the sizing agent, ●τ1 Fp: flow rate of the sizing agent FM: flow rate of the additive When V and γ are eliminated from the above equations (1) and (), the following equation () holds true.

FP=KeaTFM・・・・・・・・・・・・() Note that since the additives such as paper raw materials have a large capacity relative to the size agent, the temperature 1 of the additives does not affect the addition of the size agent. Therefore, the temperature of the sizing agent (t) becomes the temperature 1 of the additive after being added to the additive, so the temperature of the sizing agent (t)
) is used instead of the temperature 1 of the additive.

According to the above equation (), without directly measuring the viscosity M of the sizing agent, while keeping the viscosity of the mixture after adding the sizing agent constant, the flow rate (FM) of the additive, the same temperature 1, and the flow rate of the sizing agent can be calculated. (Fp
) can be experimentally determined by various changes.

In this way, after experimentally determining numerical values (substances) in advance, the flow rate (FM) of the additive and the same temperature 1 are measured at the stage of actually manufacturing the product, and these measured values and Reverse the numerical value (substitution) obtained experimentally in advance ()
By entering into the equation, it is possible to calculate the addition flow rate (Fp) of the sizing agent that can keep the viscosity of the mixture constant.

By automatically controlling the actual addition flow rate of the sizing agent to this calculated flow rate (Fp), the viscosity of the mixture after adding the sizing agent can be kept constant, which constitutes the method of the present invention. It is something that exists. The method of this invention will be explained below with reference to the drawings.

In the drawings, reference numeral 1 indicates an additive transport pipe, and 2 and 3 indicate a flow meter and a thermometer installed in the middle thereof, each of which is equipped with a converter for converting measured values into digital transmission signals.

Reference numeral 5 denotes a paste transport pipe that joins the additive transport pipe 1, and is provided with a flow rate control valve 6 in the middle.

7 is a calculator configured to obtain transmission signals from the flowmeter 2 and thermometer 3, calculate the above equation, and send the obtained transmission signal to the flow rate control valve 6, and is equipped with calculation units 8 to 12. ing.

Using the above-mentioned sizing agent addition device, first, the flow rate (Fp) of the sizing agent and the amount of the sizing agent are determined while keeping the viscosity of the mixture after adding the sizing agent constant. It is determined experimentally by changing the flow rate (FM) of the additive and the temperature 1 of the additive.

The numerical values (alternatives) obtained in the above experiment are stored in the arithmetic unit 11 of the calculator 7, and the constant (a) is stored in the arithmetic unit 8.

After the above preparations, the material to be added is actually poured into the transport pipe 1, and the sizing agent is added from the transport pipe 5. The amount of sizing agent added is automatically controlled as follows. . That is,
First, the flow meter 2 measures the flow rate (FM) of the additive. The measured value is converted into a digital transmission signal by the flowmeter 2 and sent to the computing unit 10. On the other hand, thermometer 3
The temperature CI') of the additive is measured, and the measured value is converted into a digital transmission signal by the thermometer 3 and sent to the computing unit 8. The transmission signal representing the temperature (1) is multiplied by the transmission signal representing the constant (a) in the arithmetic unit 8 and converted into the transmission signal representing (AT). The transmission signal representing (AT) is sent to the arithmetic unit 9, where it is converted into a transmission signal representing (EaT) and sent to the arithmetic unit 1.
0, where it is multiplied by a transmission signal representing flow rate (FM) and converted into a transmission signal representing (EaT-FM). The transmission signal representing the (EaT-FM) is sent to the arithmetic unit 11, where it is multiplied by a transmission signal representing a numerical value (substitute) and converted into a transmission signal representing the flow rate (Fp). The transmission signal representing the flow rate (Fp) is sent to the computing unit 12, where it is converted into a transmission signal representing the opening degree of the control valve 6 corresponding to the transmission signal. The transmission signal is sent to the control valve 6 to adjust the opening degree of the control valve 6. In this way, the amount of sizing agent added (FM) is automatically controlled. According to the method of this invention, changes in the flow rate and temperature of the additive are measured, and the flow rate of the sizing agent is automatically changed accordingly, thereby automatically controlling the amount of sizing agent added. By doing so, it is possible to maintain a constant viscosity of the mixture after adding the sizing agent.

[Brief explanation of the drawing]

The drawing is a system diagram of the equipment used to carry out the invention. DESCRIPTION OF SYMBOLS 1... Additive transport pipe, 5... Paste transport pipe, 6... Flow rate control valve, 7... Calculator.

Claims (1)

[Scope of Claims] 1. In a sizing agent addition device equipped with a material transporting pipe 1 and a sizing agent transporting pipe 5 that merges with this pipe 1 and has a flow rate control valve 6 in the middle, a sizing agent of a constant concentration is used. When adding to the additive, first, Fp = Ke^a^TF_M, where Fp: flow rate of the sizing agent, a: a constant determined by the properties of the sizing agent, and the natural logarithm of the viscosity of the sizing agent and the temperature. When the relationship is expressed as a straight line on a graph, the value of the slope of the straight line with a negative sign, T: temperature of the additive, F_M: flow rate of the additive, the value (K) that satisfies the above formula, While keeping the viscosity of the mixture after addition of the sizing agent constant, the flow rate of the sizing agent (Fp), the flow rate of the added material (F_M), and the temperature of the added material (T) are experimentally determined in advance. After the above preparation, the flow rate (F_M) and temperature (T) of the additive are automatically measured, and the values obtained by the measurement are converted into a transmission signal and input into the computer 7, and the computer 7 calculates the above formula to obtain the flow rate (Fp) of the glue as a transmission signal, and adjusts the opening degree of the flow rate control valve 6 based on the transmission signal to obtain the flow rate (Fp) of the glue.
) A method for controlling the amount of a sizing agent added at a constant concentration, the method comprising controlling the amount of sizing agent added by adjusting the amount of sizing agent added.