JPH0366145B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a method for thermally bonding a laminated sheet made of a thermoplastic adhesive plastic and a thermoplastic plastic with a higher melting point to the surface of a steel sheet pile. This invention relates to an induction heating device as a heating source.

[Conventional technology]

There are generally methods for heating magnetic materials, including steel plates, etc., using devices that generate induction heating, gas burner heating, infrared heating, ultrasonic waves, electron beams, or laser beams. are actually used in various fields.

[Problem that the invention seeks to solve]

When heating an object with a complex shape such as a steel sheet pile, or when attaching a laminated sheet made of thermoplastic adhesive plastic and a thermoplastic with a higher melting point to the steel sheet pile, the target area must be heated evenly. It is required to be heated to
For example, as is clear from JP-A No. 59-224717, JP-A No. 59-224718, and JP-A No. 59-224719, specific heating methods and utilization methods are not specified, and they are limited to methodologies only. The reality is that

However, in recent years, there has been an increasing demand for coating conventional materials with materials having anti-corrosion properties to significantly improve corrosion resistance, and for such corrosion-resistant materials.

Among these demands, there is also a need to improve the corrosion resistance of steel sheet piles, and for this purpose, studies are being conducted on attaching laminated sheets to steel sheet piles.

Looking at the heating methods used in conventional pasting methods, the gap between each part of the object to be heated, such as the steel sheet pile and the heating coil, is kept constant, or the shape of the heating coil is kept constant. In the process of thermally adhering laminated sheets, for example, by sequentially adhering the laminated sheets with a pressing roller after heating, it is not possible to maintain a uniform temperature of the steel sheet pile in the bonded area. The conditions were not uniform, and it was not possible to achieve smooth sticking properties and finished surfaces.

In other words, in the conventional manufacturing method for heavy-duty anti-corrosion steel sheet piles, when the laminated sheets are continuously fed onto the surface of the steel sheet piles that have passed through a heating device and been uniformly preheated, they are first heated by a central roller. The center of the laminated sheet is pressed against the back or belly surface of the steel sheet pile, and then a roller slightly downstream presses the corner portion of the sheet pile, and further downstream rollers press the sheet pile on both sides. is pressed against the side of the steel sheet pile and comes into close contact with it. Therefore, the downstream roller presses the laminated sheet at a low temperature with natural heat dissipation corresponding to the distance between the rollers, and when the downstream roller tries to obtain the appropriate temperature to bring the laminated sheet into close contact, the upstream roller The rollers end up pressing the laminated sheet at a temperature considerably higher than the appropriate temperature. In addition, when steel sheet piles are fed on a mechanism or fixed on equipment, heat escapes from the side that is in contact with the mechanism or equipment, causing further variation in the temperature of the steel sheet piles under each roller. There are also problems.

On the other hand, laminated sheets of thermoplastic adhesive plastics and thermoplastics (i.e., non-crosslinked plastics) have favorable strength and durability in the room temperature to low temperature range, are inexpensive, and can be easily manufactured into products of various colors and sizes. On the other hand, it lacks strength and shape stability at high temperatures, and shrinks greatly during melting and cooling, so pinholes and shrinkage tend to occur on preheated steel sheet piles, and when pressed with rollers, Surface scratches are likely to occur, and the tension of the sheet prevents adhesion at both edges of the back side and the corners of the ventral side of the steel sheet pile, making it easy for the sheet to peel off. There are problems such as the formation of thin parts, and it is necessary to suppress the temperature rise of the entire sheet as much as possible.

Therefore, in order to stably attach a laminated sheet of thermoplastic adhesive plastic and thermoplastic plastic to steel sheet piles, conventional heavy-duty corrosion-resistant steel sheet pile manufacturing equipment is insufficient, and the quality and quality of heavy-duty corrosion-resistant steel sheet piles are insufficient. Efforts to ensure reliability were desired.

[Means for solving the problem] As a result of various studies in order to respond to these surrounding requests, we decided to develop a new method for applying thermoplastic plastic to the upstream side of multiple parallel rolls that press the thermoplastic onto the surface of the steel sheet pile. In a heating device for manufacturing heavy-duty corrosion-resistant steel sheet piles that is arranged to preheat steel sheet piles, there is a measuring means for measuring the partial temperature of the steel sheet piles immediately before each roll, and a measuring means for measuring the temperature of the steel sheet piles in the transverse direction of the steel sheet piles. It is characterized by comprising a heating coil means that can change the distribution, and a control means that controls the heating coil means based on the output of the measuring means so that the steel sheet pile has approximately the appropriate temperature under each roll. We have achieved a heating device for manufacturing heavy-duty anti-corrosion steel sheet piles.

Here, the heating coil means is equipped with a gap adjustment mechanism that can arbitrarily adjust the partial interval between the heating coil and the steel sheet pile, and adjusts the interval for each part in the transverse direction of the steel sheet pile to increase the temperature of the steel sheet pile. The distribution may be changed.

[Effect]

When attaching a laminated sheet to a specific surface of steel sheet piles, it is necessary to control the gap between the heating coil and the steel sheet pile so that the temperature of the relevant area is constant, or to control the shape of the coil, and also to increase the input power. It is intended to make the application conditions of each part uniform by controlling the adhesive.

In order to achieve this purpose, thermometers are installed immediately after the exit of the heating coil and at the installation point of the pressing roller that presses the laminated sheet, and the temperature of the steel sheet pile on the exit side of the heating coil is T, and the temperature of the steel sheet pile immediately before the pressing roller is measured. When the temperature is T' and the target temperature for laminating the laminated sheet is _T0 , compare _T0 and T', control the input power to keep T' within _T0 ±5℃, and keep the lamination temperature constant. In addition to controlling the laminating temperature to be constant, when laminating the supplied laminated sheet to the steel sheet pile surface, it is pressed to prevent wrinkles and air entrainment while pressing the supplied laminated sheet onto the surface of the steel sheet pile. It is necessary to consider the positional relationship of the equipment.

Specifically, to explain using the schematic diagram shown in Fig. 1, A, B, and C, which constitute the main surfaces of the steel sheet pile,
In terms of this, it is desirable that the temperature distribution of each surface be such that the A side temperature < B side temperature, B side temperature = C side temperature, and it is necessary to perform temperature control so that the above relationship is established. .

In the figure, 1 is a steel sheet pile, 2 is a heating coil, 3 is a pressing roller, and 4 is a thermometer.Although not shown in the figure, the gap between the heating coil and the steel sheet pile is managed and the laminated sheet is pasted. A gap control device is provided to keep conditions constant.

Note that the temperature measuring means at this time may be either a contact method or a radiant heat detection method.

As the temperature control device, for example, one of the type shown as an example in FIGS. 2 and 3 can be used.

This figure 2 shows the skeleton of the entire temperature control device. The input signal fed back from the temperature sensor is compared with a reference value set in advance in the temperature controller, and a predetermined voltage is set depending on the increase in the input signal. Output the output signal to the voltage regulator,
The individually processed signals are sent to the power supply device, which supplies a predetermined amount of power to the heating coil to heat it.

FIG. 3 shows the logic in the temperature regulator of FIG.

The above-mentioned temperature distribution relationship between surfaces A, B, and C of the steel sheet pile is the same even when the direction of the unevenness of the steel sheet pile is reversed, and the temperature behavior of surface A and surface B or C is The trajectory roughly resembles the graph in Figure 4.

Furthermore, the heating coil 2 can be of three types as shown in FIGS. 5, 6, and 7.
Either method may be used.

To explain each of these heating coils, first, the method shown in FIG. 5 is an axial magnetic flux coil heating method, in which a shows a front view, b shows a plan view, and c shows a perspective view. Inside, 5 is a power supply terminal, 6 is a coil cooling water pipe, and 7 is a core.

The method shown in Fig. 6 is an example of a vertical magnetic flux type integrated heating coil, where a is a front view, b is a partial plan view, and c
is a perspective view, and d is a front view showing the case where the surface of a concave steel sheet pile is treated.

Further, the example shown in FIG. 7 shows an example in which divisional heating is performed using a vertical magnetic flux type.

In addition, in this example, the traveling direction of the target steel sheet pile 1 needs to be made to travel in the direction shown by the arrow.

However, not only can the target surface be treated regardless of the unevenness of the steel sheet pile, but also the gap between the steel sheet pile and the heating coil can be easily managed. It is preferable to adopt an axial magnetic flux type heating coil system as shown in FIG.

〔Example〕

Below, an example in which an induction heating device is applied as a heating source of a heating device for manufacturing heavy corrosion-resistant steel sheet piles,
This will be explained with reference to FIG.

The relationship between the steel sheet pile 1 and the heating coil (heating device) 2 only needs to be one in which either one moves.
In the case of this example, the case where the steel sheet pile 1 moves is shown.

In this case, if the laminated sheet is to be transported from the left side to the right side in the figure at a constant speed, the heating coil exit side and the portion immediately before the pressing roller 3 on the laminated sheet pasting surfaces A, B, and C, respectively. A thermometer 4 is placed at each of the two, and the detected temperature information is input to the temperature control device.

The temperature control device has a temperature regulator, a voltage regulator, a power supply, and a heating coil as shown in the circuit of Figure 2, and at the same time, they send out signals in sequence, and at the same time It has an yield back loop and a temperature feed back loop.

In Fig. 1, the heating coil outlet temperature standard of side A of steel sheet pile 1 is Ta, the measured value is Ta', and similarly the temperatures of sides B and C are Tb and Tb', these values are Letting the respective outputs be α and β for comparison, when α≧β, the output of the temperature controller is α, and when α<β×Ta′, the output of the temperature controller is β×
Let it be Ta′.

However, it is assumed that there is a relationship β×Ta′<Ta Limit.

Here, the preset temperature pattern of Ta and Tb is shown in FIG. 4, and the specific value of Ta<Tb is set to, for example, about Tb=Ta+10.

Further, as a matter of course, Ta and Tb are heating temperatures that take into account the temperature drop from the completion of heating to the time when the laminated sheet is attached.

In the voltage regulator (AVR), the output of the temperature regulator, that is, the input (reference) of the AVR, is set as V _ref and compared with the power supply output V, and the voltage applied to the heating coil is controlled, ultimately controlling the power input to the steel sheet pile. It is controlled so that the target temperature can be achieved.

Next, the temperature Ta of A and the temperature Tb of B and C surfaces are,
By controlling the gap between the heating coil and the steel sheet pile so that Ta<Tb, or by changing the shape of the coil, it is possible to obtain a pasting temperature T ₀ with the behavior shown in Figure 4, for example. , the pasting conditions can be kept constant.

Furthermore, the gap relationship between the A side, B, and C sides is as follows.
Let ta<tb, tb=tc.

Each heating coil will be further explained below using FIGS. 5 to 7.

In the figure, 1 is a steel sheet pile, 2 is a heating coil, 5 is a power supply terminal, 6 is a pipe for cooling the heating coil, and 7 is a core.

In the case of Fig. 5, it is an axial magnetic flux type heating coil, and the steel sheet pile 1 is heated on the circumference by the heating coil 2.
This method involves winding a coil with N turns (approximately 15 to 30 turns) with a gap at a constant tb.

FIG. 6 shows the shape of a vertical magnetic flux type integral heating coil, in which a indicates a steel sheet pile convex heating coil and b indicates a concave heating coil.

In either of the heating coils shown in Fig. 5 or 6, the gap amount between the steel sheet pile 1 and the heating coil 2 is always set as ta > tb, and the temperature relationship of Ta < Tb shown in Fig. 4 is obtained. It is intended to do so.

That is, these heating coils are provided with a gap control device, and the gap control device includes a feed screw attached to the heating coil that can be adjusted up and down,
It consists of a servo motor that drives this and a setting device that sets the gap value.

These control the gap between the heating coil and the steel sheet pile by moving the heating coil up and down according to the size of the steel sheet pile. For example, as the size of the steel sheet pile increases, the thickness of the main body surface becomes thicker, and as a means of heating within a certain period of time (within the heating coil passage time), the gap _tA is reduced, and conversely, as the sheet pile becomes thinner, the gap
This is a device that greatly adjusts _tA and controls it so that the target temperature is obtained. However, in any case, it is necessary to maintain the gap relationship between the heating coil and the steel sheet pile at each location such that ta>tb and tb=tc.

In addition, Ta can be adjusted without using a gap control device.
As a means of obtaining a temperature difference of <Tb, it is possible to insert the core 7 between the layers of the heating coil 2 in the part that heats the B and C sides of the steel sheet pile 1, or to change the shape of the heating coil 2. It is also possible to vary the magnetic flux density so that the B and C planes are higher in temperature than the A plane, that is, Tb=Ta+10°C.

According to the former method, each of the concave and convex heating surfaces can be achieved with one heating coil 2, and has the feature that it can be used in common for several types of steel sheet piles.

The last figure, Figure 7, shows an example of a vertical magnetic flux split heating coil.
A heating coil 2 is provided so that each surface and each part can be heated individually.

For this heating coil 2, there are two methods: sharing the power supply device and dividing the heating coil 2 individually. In the former case, an appropriate heating temperature can be obtained by the same method as the idea of the integral heating coil 2 in FIG. 6. However, since the gap adjustment device allows the gap control of each heating coil 2 alone, it is possible to easily set the relationship ta<tb in the gap between the steel sheet pile 1 and the heating coil 2.

Therefore, the core 7 inserted between the coil layers in FIGS. 5 and 6 becomes unnecessary.

In the latter case, by providing each heating coil 2 with a power supply device, the gap between the steel sheet pile 1 and the heating coil 2 in the same figure is kept constant, and by controlling the input power individually, Tb<Ta, that is, specifically, , a temperature of Tb=Ta+10°C can be obtained.

In the heating method shown in FIGS. 6 and 7, it is necessary to provide a heating coil 2 for each concave and convex surface of the steel sheet pile 1, and a heating coil 2 is required for each size of the steel sheet pile.

As mentioned above, the heating coil 2 has 3
There are several methods, but the axial magnetic flux heating method uses steel sheet piles 1
It can be used for both concave and convex surfaces, and not only can the gap amount between the steel sheet pile and the heating coil 2 be easily managed, but also the gap between the steel sheet pile and the heating coil 2 can be changed even if the size of the steel sheet pile changes.
-3 sizes have the advantage that heating can be performed with the same heating coil 2.

The frequency used as a heating power supply device is low frequency ~
High frequency or a mixture of these may be used, but in the process from heating to pasting the laminated sheet, it is important to ensure that the pasting is heated uniformly and that there is a small temperature difference between the surface and the inside, resulting in better workability. Considering this, lower frequencies are preferable.

〔Effect of the invention〕

As detailed above, according to the present invention, the following effects can be expected.

When heating steel sheet piles, the heating target temperature and the steel sheet pile temperature on the exit side of the heating coil are measured and calculated to control the input power, taking into account the temperature drop from heating to the point where the laminated sheet is attached. Since the gap between the steel sheet piles is controlled or the shape of the heating coil is changed, the temperature at the area where the laminated sheet is attached can be kept constant.

It does not require test heating and can be heated and pasted from the tip of the steel sheet pile, and by measuring and calculating the temperature at the heating coil exit side of the steel sheet pile and the part where the laminated sheet is pasted, it is possible to control the temperature in consideration of changes in ambient temperature.

Therefore, it is possible to provide a heating device for steel sheet piles that can always maintain uniform lamination conditions for laminated sheets and reliably produce products of constant quality with smooth pasting properties and finished surfaces.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing the relationship between the steel sheet pile, heating coil, and thermometer, Fig. 2 is a block diagram showing the skeleton of the temperature control device, Fig. 3 is a block diagram showing the logic of the temperature controller, FIG. 4 is a graph showing the heating temperature pattern of each part to which the laminated sheet is attached, and FIGS. 5 to 7 are configuration diagrams showing the structure of the heating coil. 1... Steel sheet pile, 2... Heating coil, 3... Pressing roller, 4... Thermometer, 5... Power supply terminal, 6... Coil cooling water pipe, 7... Core.

Claims (1)

[Scope of Claims] 1. A heating device for manufacturing heavy corrosion-resistant steel sheet piles that is disposed upstream of a plurality of parallel rolls that press thermoplastic plastics onto the surface of steel sheet piles and preheats the steel sheet piles. A measurement means for measuring the partial temperature of the steel sheet pile just before the rolls, a heating coil means that can change the temperature distribution of the steel sheet pile in the transverse direction of the steel sheet pile, and a heating coil means that allows the steel sheet pile to reach almost the appropriate temperature under each roll. A heating device for producing heavy corrosion-resistant steel sheet piles, comprising: a control means for controlling a heating coil means based on the output of the measuring means so that the following is achieved. 2. The heating coil means is equipped with a gap adjustment mechanism that can arbitrarily adjust the partial interval between the heating coil and the steel sheet pile, and adjusts the interval in the transverse direction of the steel sheet pile to change the temperature distribution of the steel sheet pile. A heating device for producing heavy corrosion-resistant steel sheet piles according to claim 1.