JPH06294091A - Dryer and device for controlling profile of water content - Google Patents

Abstract

PURPOSE:To arrange a device in a reduced space, to facilitate handleability, maintenance and installation and to reduce the number of parts, etc. CONSTITUTION:A dryer part of a paper machine is equipped with a microwave generator 2, a high-voltage electric source device 1, a waveguide 4, a circulator 5, a matching device 6, a control panel 3 and a dry hood 7, and microwave 9 is uniformly emitted to paper 9 passing through the dry hood 7 so that heat is generated by molecular movement of water itself in the interior of the paper 9 and the surface and the interior of the paper are simultaneously and uniformly heated in proportion to applied energy to dry the paper 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dryer and a moisture profile control device applied to paper machines, coaters and the like.

[0002]

2. Description of the Related Art The dryer part of a conventional paper machine is a system for supplying necessary energy to paper and is dried by steam. FIG. 8 shows a conventional dryer. This dryer has several cylinder dryers 18 for drying paper, and a drive device 2 for driving the cylinder dryer 18.
0, a canvas 19 for carrying paper, a canvas roll 12, a hood 21 for preventing heat dissipation, and a dray screw system 26 for sending steam to the cylinder dryer 18. The dray screw system 26 supplies a required amount of steam from the steam header 22 to the cylinder dryer 18 by the control valve 23, and supplies a part of the used steam to the former dryer 18 by the control valve 23 for reuse. The rest is a system for recovering to the boiler through the separator 24 and the pump 25. FIG. 9 shows a conventional dryer, and the cylinder dryer 18 has a total length of about 30 m, which occupies about 1/3 of the total length of the paper machine. In the figure, 9 is paper, 14 is a press, 15 is a size press, 16 is a calendar, 17 is a vacuum felt roll, and 19 is a canvas.

As a conventional moisture profile control device, there are an induction heating system, a steam injection system, a water mist spraying system, an infrared radiation system, etc., all of which are mounted at a constant pitch in the width direction of the roll as shown in FIG. The actuator 27, the controller 28 for outputting an output command to the actuator 27, and the BM system 29 for calculating the output value of each actuator 27 based on the measurement result of the water content of the paper and giving the controller 28 an instruction. ing. Further, each actuator 27 outputs each individually according to the instruction of the controller 28 which is output based on the measurement result of the BM system 29 so as to make the moisture profile uniform.

[0004]

The dryer part of the conventional paper machine occupies 1/3 of the entire paper machine as shown in FIG. 9, which is about 30 m in length. This is because it is dried by steam, and it was a necessary space in the conventional system that supplies the required thermal energy to the paper 9.
Therefore, in the past, steam supply was divided into groups, pressure control and temperature control were performed for each group, and machine speed control was performed for each group to absorb the expansion and contraction of the paper so as not to impair the quality during the paper drying process. Or because one side of the paper hits the cylinder dryer,
Grouping has been proposed so that both sides hit. Further, when the paper is passed after the paper is cut, the cut end is wrapped around the cylinder dryer 18, so the work of blowing air off with an air hose and the regular replacement of the canvas 19 are labor-intensive and dangerous labor.

On the other hand, in the apparatus of FIG. 10, the BM system 29
It was necessary to tune the measurement point of the water content measured in 1 above and the position of the actuator 27 that outputs. In addition, the number of actuators 27 is large and there is a drawback that it is very troublesome including installation. Furthermore, since the number of actuators 27 is large, the failure rate is high and maintenance is troublesome. Further, complicated software such as compensation for paper shrinkage and burr zone control is required for automatic operation. there were. The present invention has been proposed to solve the above conventional problems.

[0006]

Therefore, the present invention provides a dryer part of a paper machine including a microwave generator, a high-voltage power supply device, a waveguide, a circulator, a matching box, a control panel, and a drying hood. It applies waves to dry the paper that passes through the drying hood, which is a means for solving the problem. Further, the present invention provides a moisture profile control device, including a microwave generator, a high-voltage power supply device, a waveguide, a circulator,
Equipped with a matching box, operation panel, and drying hood to diffuse microwaves in the drying hood and evenly apply microwaves to the surface of the paper passing through the hood to make the moisture profile in the width direction uniform. This is a means for solving the problems.

[0007]

By uniformly applying microwaves to the paper, heat is generated due to the molecular motion of water inside the paper, and the surface and the inside of the paper are heated uniformly at the same time in proportion to the applied energy to dry the paper. In the invention of claim 2, by uniformly applying microwaves to the paper, the surface of the paper and the inside of the paper are made uniform at the same time by the molecular motion of the water inside the paper, and heat is generated according to the amount of water. To obtain a uniform moisture profile on the paper.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments of the drawings. FIGS. 1 to 7 show the embodiments of the present invention. First, in FIG. 1, the dryer 13 comprises a microwave generator 2, a DC high voltage power supply 1, a waveguide 4, a circulator 5, a matching box 6 and a control panel 3, and a microwave 8 is provided on the inside surface of the hood. The paper 9 is dried by diffusing the waves in the drying hood 7 that has been subjected to a process that diffuses the waves, and uniformly applying the microwaves to the surface of the paper 9 passing through the hood 7. In addition, as a layout, a batch microwave depending on the type of paper 9,
Separate microwaves (cylinder dryer + microwave) etc. will be used properly. The microwave (electric power) 8 generated by the microwave generator 2 is transmitted through the waveguide 4 to the drying hood 7, which is a heating unit, and is diffusely reflected therein to pass through the drying hood. Dry the water of 9. In the middle of the waveguide 4, there are a circulator 5 that attenuates the reflection (power) from the inner surface of the waveguide 4 and a matching device 6 that attenuates the reflection (power) from the inner surface of the drying hood 7.
The microwave generator 2 is protected. Further, the drying hood 7 also has a leakage prevention function for preventing leakage of microwaves (electric power) to the outside of the dryer.

FIG. 2 shows a case in which the entire dryer is heated at once, in which 13 is a dryer, 14 is a press, and 16 is a calendar. FIG. 3 shows a case in which the size press 15 is provided between the dryers and heating is performed in two parts. FIG. 4 shows a case where the dryer 13 is divided into several pieces and heated so as to be gradually dried. FIG. 5 shows a case where a part of the cylinder dryer 18 is left outside the drying hood 7, where 17 is a vacuum felt roll and 19 is a canvas. FIG. 6 shows a case where the cylinder dryer 18 is partially left in the drying hood 17.

Next, the second embodiment of FIG. 7 will be described. The apparatus of FIG. 7 includes a microwave generator 2, a DC high voltage power supply 1, a waveguide 4, a circulator 5, a matching box 6 and an operation panel 3. The output value of the microwave 8 is determined according to the instruction from the BM system 32, and the microwave 8
The surface of the inside of the hood is diffusely reflected in the dry hood 7 that is processed to diffusely reflect microwaves, and the microwave 8 is uniformly applied to the surface of the paper passing through the dry hood 7 to make the moisture profile in the width direction uniform. I am trying to.

Now, in FIG. 7, the microwave (power) 8 generated by the microwave generator 2 is transmitted through the waveguide 4 to the drying hood 7 which is a heating portion, and is diffusely reflected therein, The moisture of the paper 9 passing through the drying hood 7 is dried to adjust the profile. In the middle of the waveguide 4, the reflection (power) in the waveguide 4 is attenuated to attenuate the reflection (power) from the circulator 5 that protects the microwave generator 2 and the drying hood 7. There is also a matching device 6 that also protects. Further, the leakage prevention device 30 allows the dry hood 7
To prevent the microwave 8 from leaking to the outside. 31
Is a moisture measuring sensor, and 33 is a BM meter (moisture measuring device). In addition, the device of FIG. 7 has an automatic mode in which heating is automatically controlled according to the result measured by the BM system 32,
It has two operation modes, a manual mode in which heating is preset and controlled by manual setting. Further, the control can be performed only by raising and lowering the heating frequency and turning it on and off, and at the same time, profile control can be performed while keeping the average target value of the moisture content, which is a simpler algorithm than the conventional one. In addition, the configuration is simple and the adjustment is easy, and in normal maintenance, the replacement of microwave generation electrode tubes (klystron, magnetron, vacuum tube, etc.) is about 3 years for klystron and about half a year for others.

[0012]

As described in detail above, according to the present invention, by heating and drying by microwaves, a few cylinder dryers can be reduced or eliminated, and the steam system (dray screw system) is also reduced. Or it can be eliminated, and the overall structure can be compact and simple. Therefore, it is possible to save space, improve operability and maintainability, and reduce work time when paper is cut and canvas is replaced. Also, since the paper is heated and dried from the inside, high quality (reduction of moisture spots, warpage, curl) can be achieved, it is not necessary to consider the front and back of the paper, and energy efficiency is improved.
Cost can be reduced. Further, in the present invention, by utilizing the diffused reflection of microwaves and the heat generation effect according to the amount of water in the microwaves, it is possible to eliminate the actuators to be individually installed. Therefore, the installation and adjustment are simple and simple. Can be configured. Since the device configuration is simple as described above, it is possible to improve the aspects of installation, adjustment, and maintenance, and it is not necessary to tune the measurement point and actuator position, which makes installation easy and reduces the number of parts. It is possible to reduce the failure rate and to eliminate the need for complicated control software.

[Brief description of drawings]

FIG. 1 is a system diagram of a dryer according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a first example of the dryer arrangement.

FIG. 3 is a block diagram showing a second example of the dryer arrangement.

FIG. 4 is a block diagram showing a third example of the dryer arrangement.

FIG. 5 is an explanatory diagram showing the arrangement structure of the dryer near the drying hood, which is different from FIG.

FIG. 6 is an explanatory view showing the inside of a drying hood different from that in FIG.

FIG. 7 is a system diagram of a moisture profile control device showing another embodiment of the present invention.

FIG. 8 is a system diagram showing a conventional dryer.

FIG. 9 is a layout showing a dryer having another conventional configuration.

FIG. 10 is an explanatory diagram of a conventional moisture profile control device.

[Explanation of symbols]

 1 DC high voltage power supply device 2 Microwave generator 3 Operation panel 4 Waveguide 5 Circulator 6 Matching device 7 Drying hood 8 Microwave (electric power) 9 Paper 10 Bed 11 Paper roll 12 Canvas roll 13 Dryer 14 Press 15 Size press 16 Calendar 30 Leakage prevention device 31 Moisture sensor 32 BM system 33 BM meter

Claims (2)

[Claims] 1. A dryer part of a paper machine, which is provided with a microwave generator, a high-voltage power supply device, a waveguide, a circulator, a matching box, an operation panel, and a drying hood, and passes through the drying hood by applying microwaves. Dryer characterized by drying the paper. 2. A moisture profile control device comprising a microwave generator, a high-voltage power supply device, a waveguide, a circulator, a matching box, an operation panel and a drying hood, wherein microwaves are diffused and reflected in the drying hood. A moisture profile control device characterized in that a microwave is uniformly applied to the surface of paper passing through the hood to make the moisture profile in the width direction uniform.