JPS622066B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel fabric temperature monitoring method in a continuous heat treatment apparatus for drying or setting dyed fabrics. In recent years, there has been a strong demand for continuous heat treatment equipment, such as heat setters that dry and set cloth with hot air, to measure the cloth temperature and operate optimally. Optimal operation in heat setting means that the fabric reaches an effective setting temperature at which it sets by heating with hot air, and that the setting temperature is maintained for a period of time determined for quality.In other words, the effective setting time is optimal so that it does not become excessive or insufficient. There is no choice but to drive at transfer speed. Therefore, in order to perform optimal operation, it is desirable to first measure the effective setting time of the cloth in its current state, and, if there is a difference from the set value, to be able to immediately command a corrected cloth transfer speed that will bring about the optimum condition. To this end, it is important to measure the fabric temperature in the heat setter as it increases.

As a way to know this heating type, for example, the length is 20m.
It is conceivable to install a large number of infrared thermometers for measuring the temperature of the cloth in the direction in which the cloth is transported in the heat setter, but this has the disadvantage that the equipment is expensive. The present invention solves these problems and instructs the optimum transfer speed of cloth, and its gist is as follows:
The fabric temperature, the fabric transfer speed, and the hot air temperature, which are measured at two different temperature increase positions in the fabric transfer direction, are input into an arithmetic device that calculates the fabric temperature increase characteristic as a first-order lag function. The temperature rise time constant of the cloth is determined, and the cloth transfer speed is calculated and corrected in order to satisfy the set cloth setting time at this time.

Hereinafter, the present invention will be specifically explained based on the accompanying drawings.

FIG. 1 shows a typical rise in cloth temperature when a water-containing cloth is heated in a heat setter, with the vertical axis representing the cloth temperature and the horizontal axis representing the heating time. In other words, constant rate drying is performed from the start of heating until t ₀ seconds, and then lapse rate drying begins and the temperature rapidly rises, approaching the hot air temperature Ts over time. It has been found that it can be approximated by a first-order lag function, and in the present invention, the arithmetic device is configured with the temperature rise characteristic as a first-order lag function. Furthermore, in the present invention, infrared thermometers are installed at two points at different temperature increase positions in the lapse rate drying region, that is, the temperature increase region, for example, points a and b in FIG. 1, to measure the temperature of the cloth. temperature
Input T ₁ and T ₂ to the arithmetic device. The reason why we decided to measure the fabric temperature at two different heating points is as follows.
Temperatures T ₁ and T ₂ during the heating process at two points, and hot air temperature Ts
By inputting the fabric speed ν at that time into the calculation device, the temperature increase pattern as shown in Fig. 1 can be obtained for the first time. It is impossible to seek form.

Since the cloth temperature in the temperature rising region in FIG. 1 is assumed to be a first-order lag function, it is expressed by equation (1).

T=(Ts−T ₀ )(1−e−t−t ₀ /τ)+T ₀ …(1) formula Here, T ₀ is the constant rate drying temperature of the cloth, which is generally 60 to 80
It is between ℃. Since the effect of a change in the value of T ₀ on equation (1) is small, there is no problem even if T ₀ =70°C. Of course, measuring the cloth temperature at T ₀ and inputting it to the arithmetic device does not interfere with the present invention.

The size of τ in equation (1) is the temperature rise time constant of the cloth, which is proportional to the density and specific heat of the cloth, and inversely proportional to the coefficient of heat transfer from hot air to the cloth. This comprehensively indicates the quality of the heating ability. If the temperature increase time constant τ and the end point of constant rate drying, that is, the temperature increase start point t ₀ time are found, the form of the overall cloth temperature can be expressed as shown in FIG.

The distances l ₁ and l ₂ from the heat setter inlet to the first temperature increase measurement point a and the second temperature increase measurement point b are known, and the heating time to the above points a and b is determined by measuring the cloth speed ν. Calculate t ₁ = l ₁ /υ and t ₂ = l ₂ /υ, and let the cloth temperature at that time be T ₁ at point a and T ₂ at point b. These numbers are (1)
By substituting into the equation, find the time t ₀ of the temperature rise start point and the temperature rise time constant τ of the cloth using the following equation.

In other words, the arithmetic device serving as a first-order lag function that constitutes the present invention has the function of calculating equations (2) and (3) described above, and has the function of calculating equations (2) and (3) described above.
By inputting the cloth temperature at a point, the cloth transfer speed, and the hot air temperature, the temperature rise characteristics of the cloth that changes from moment to moment are calculated and measured, and based on the results, the form of cloth temperature change is displayed on a cathode ray tube or printer. It has the ability to display.

FIG. 2 shows an example in which a polyester fabric was dried and set in a heat setter having eight heating zones. Reference numeral 1 denotes a heat setter that performs hot air heating, and the hot air whose temperature is controlled to 190°C is blown onto the cloth 2 being transferred in each room to heat it. 3 is a nip roller that transfers the cloth.

In this embodiment, such a heating device is provided with infrared thermometers 4 and 5 for measuring the temperature of the fabric, with the temperature raising position of the first point being placed after the second chamber, and the position of the second point being placed in the fourth chamber. Each fabric temperature signal from the infrared thermometer is
Cloth speed meter 6 installed to measure cloth transfer speed
The velocity signal from the hot air temperature signal and the hot air temperature signal from the thermoelectric thermometer 7 provided for measuring the hot air temperature are both input to the arithmetic unit 9 through the interface 8.

The arithmetic device 9 has the above-described arithmetic function as a first-order lag function, and a microcomputer, for example, is used as the arithmetic device. According to the example, the hot air temperature is 190℃ and the cloth speed is 40m/min.
At this time, the time t ₀ of the temperature increase start point calculated by the arithmetic unit 9 is 7.1 seconds, and the temperature increase time constant τ of the cloth is 5.2 seconds, and the a curve in FIG. 3 corresponds to the result of the above example. This is a characteristic curve of cloth temperature plotted based on the figure. Curve b is a characteristic curve of cloth temperature at correction speed.

In this embodiment, the current setting time is calculated by the arithmetic unit 9 when the effective setting temperature Tf of the cloth is 175°C. That is, when the effective set temperature Tf is given as a set value to the arithmetic unit 9, the set time Δt is calculated as Δt=l/υ−(τ・logeTs−T ₀ /Ts−Tf+t ₀
)... Since it has a function that can be calculated as equation (4), after the temperature increase time constant τ and temperature increase start time t ₀ are calculated, the set time Δt can be easily calculated. Here, l is the total length of the heat setter and is a known quantity.

In addition, the optimum cloth transfer speed υ _f for the set value △t _f of the effective setting time can be calculated by substituting both into equation (4). The calculation device 9 can immediately calculate and display the optimal speed υ _f by inputting the set values of the effective set temperature and set time.

According to this example, the actual setting time at the initial speed of 40 m/min is 12.5 seconds, and the optimum cloth transfer speed to satisfy the optimum setting time of 6 seconds is
He ordered the speed to be adjusted to 48m/min.

As a result of the modification, we were able to obtain a product with stable quality.

As is clear from the above examples, the present invention makes it possible to continuously grasp the temperature rise process of the cloth during heat treatment, and furthermore, it is possible to know the effective set time under the current operating conditions and set the value. If there is a difference in the set time, it is possible to immediately command the corrected value of the transfer speed and start operation, which greatly contributes to improving production quality and productivity. be.

[Brief explanation of the drawing]

Figure 1 shows the general rise in cloth temperature when a water-containing cloth is heated in a heat setter, Figure 2 is a schematic diagram of a heat setter device with eight heating zones, and Figure 3 is a characteristic curve of cloth temperature plotted based on the results of operation according to the method of the present invention. 1... heat setter, 2... cloth, 3... nip roller, 4, 5... infrared thermometer, 6... cloth speed meter, 7... thermoelectric thermometer, 8... interface, 9... calculation Device.

Claims (1)

[Claims] 1. In a continuous heat treatment device, the temperature increase characteristic of the cloth is 1.
The time constant for temperature increase of the cloth is determined by inputting the cloth temperature, which is measured at two different temperature increase positions in the cloth transfer direction, to a calculation device serving as a next lag function, the cloth transfer speed, and the hot air temperature. A driving method for monitoring the temperature of cloth during running, characterized in that: 2 In the continuous heat treatment equipment, the temperature rise characteristic of the cloth is
The time constant for temperature increase of the cloth is calculated by inputting the cloth temperature, which is made to be measured at two different temperature increase positions in the cloth transfer direction, to a calculation device serving as a next lag function, the cloth transfer speed, and the hot air temperature. , and calculates a cloth transfer speed to satisfy a set cloth setting time and issues a correction command.