JPH0223798B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for drying materials to be dried such as printed paper, plastic film, metal film, fibers, boards, and the like.

Immediately after printing, a continuous object such as paper or a film coated with paint or coating agent is sent into a drying device and heated with a burner to dry it after the printing process or coating process. Hot air is blown onto the surface of the continuous material passing through it at high speed, thereby evaporating the solvent or moisture and drying it. However, the current situation is that a considerable amount of the thermal energy consumed for drying such continuous materials is released into the atmosphere as exhaust loss, which is a major problem from the perspective of efficient energy use. is being raised as an issue.

The present invention has been made in view of the current situation, and an object of the present invention is to provide a continuous material drying device that can reduce exhaust loss as much as possible, utilize thermal energy effectively, and reduce energy consumption. The purpose is to

The present invention, which was made to achieve such an object, has a first drying zone and a second drying zone separated by a partition wall.
drying zones are arranged in sequence in the flow direction of the material to be dried, a heating device and a blower device are installed in each of the first drying zone and the second drying zone, and the heating device and the blower device are installed in the second drying zone. The blower device is operated to follow the heating device and the blower device in the first drying zone.

In the present invention, a burner heating device and a blower device are respectively installed in a first drying zone and a second drying zone, and a paper thermometer 16 is provided on the outlet side of the material to be dried in the second drying zone. Burner 1 in the first drying zone is activated based on a burner opening increase/decrease command signal sent in accordance with the temperature detected from the thermometer.
A burner opening/closing control device is provided to control the opening degrees of burners 19 in the drying zone 8 and the second drying zone in the direction of increasing or decreasing, respectively, and the opening degree is 0 or the minimum combustion opening degree.
In a drying device that controls a burner opening between V0 and a maximum combustion opening of 100%, opening/closing control of the other burner 9 is performed when the opening of the one burner 18 is equal to or greater than a predetermined amount V1 (V1>V0). A switch mechanism for controlling the device, and control of an opening/closing control device for the one burner 18 when the opening degree of the one burner 18 is 100% and the opening degree of the other burner 19 is a predetermined amount (V2>V1) or more. This drying device is characterized by being equipped with a switch mechanism that stops the operation.

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

FIG. 1 is a schematic diagram of a drying device of the present invention, which is used as a drying device for an offset rotary press.

The peripheral wall 1 is covered with a heat insulating material such as rock wool to prevent the heat inside the drying device from dissipating to the outside. A printing paper inlet 4 into which the printing paper W immediately after printing enters is opened on the side of the offset rotary press of the peripheral wall 1, and a printing paper outlet 5 is opened on the opposite side, that is, on the paper discharge device side. The shapes of the printing paper inlet 4 and the outlet 5 are horizontally long rectangles.
Shutters 7 and 8 operated by a power device such as an air cylinder are installed above and below the printing paper inlet 4 and outlet 5 to prevent excessive air from entering the drying device from the outlet 5 and lowering the temperature inside the drying device. is provided with a large opening only when the printing paper W is passed through the drying device for the first time, and slides in the direction of closing the shutters 7 and 8 during operation to close the printing paper inlet 4.
The gap between the outlet 5 and the outlet 5 can be made as small as possible. In a preferred embodiment, the shutters 7 and 8 allow the vertical distance between the printing paper inlet 4 and the printing paper outlet 5 to be adjusted within a width of 10 mm to 30 mm.

A partition wall 2 is provided in the center of the drying device, which divides the drying device into a first drying zone and a second drying zone.
A horizontally long rectangular printing paper insertion hole 6 is formed in the center of the partition wall 2 .

The first drying zone and the second drying zone are communicated with each other by a ventilation pipe 3, and a damper 15 is disposed in the middle of the ventilation pipe 3 so that it can be opened and closed. Furthermore, exhaust pipes 9 and 10 are provided in the first and second drying zones, respectively, and dampers 11 and 12 are installed on these exhaust pipes to adjust the opening and closing of the exhaust pipes. Together, they form an exhaust pipe 13 and communicate with a deodorizing device. Note that a damper 14 is also provided on the exhaust pipe 13 and controls opening and closing thereof.

The first drying zone and the second drying zone each have a heating device and a blower device or burners 18, 19.
and fans 20 and 2 driven by motors 22 and 23
1 is installed.

Fuel (for example, liquefied natural gas) and air are fed into the burners 18 and 19.
The printing paper W is dried by blowing the air heated by the drying zone 9 onto the paper surface using the fans 20 and 21. fan 2
The wind speed of 0,21 is adjustable, and in this example
Good results have been obtained at wind speeds of 50 m/s to 70 m/s.

Further, the combustion state in the burners 18 and 19 is measured by a printing paper surface thermometer 16, which is an infrared type surface thermometer placed immediately after the printing paper outlet 5, and is automatically controlled via the paper surface temperature setting section 17 depending on the paper surface temperature. combustion is controlled. In other words, assuming that the combustion state (that is, the amount of thermal energy supplied) is constant, if the printed matter contains a large amount of ink, the amount of solvent will also be large, and of course a large amount of thermal energy will be taken away due to evaporation of the container, causing the paper surface to deteriorate. The temperature decreases, and conversely, if the amount of ink in the printed matter is small, the amount of solvent is small, and the thermal energy needed to evaporate the solvent is also small, so the temperature of the paper surface increases accordingly. In this way, the combustion state can be controlled by the temperature of the paper surface immediately after drying, and the temperature of the paper surface immediately after drying measured by the thermometer 16 is set at a certain temperature (110° C. to 130° C. in the preferred embodiment) by the paper surface temperature setting section 17. , and if the paper surface temperature falls below the set temperature, turn on burner 18 or 19.
The burner 18 or the burner 18 or 19
By forming a so-called feedback loop that reduces the amount of burnt paper, the surface temperature of the paper can be kept constant and good drying can be achieved at all times.

In this way, in the present invention, the paper surface thermometer 16
Burner opening/closing control is performed based on a burner combustion increase or decrease command signal (combustion instruction degree based on the number of positive or negative pulses, etc.) transmitted from the paper surface temperature setting unit 17 in response to the paper surface temperature measured by The device is operated to control the combustion opening degree of burners 18 and 19 (burner opening degree such as fuel supply opening/closing degree).
9 is a graph showing the relationship between the burner opening degree and the burner opening degree, with the horizontal axis representing the burner combustion indication degree based on the feedback system from the paper surface temperature, and the vertical axis representing the burner opening degree. ,
indicates the burner 19. When printing is stopped, both burners 18 and 19 do not need to dry the printing paper W, so the burner opening degree is maintained at 0 or the minimum combustion opening degree V0 by the burner opening degree control device. When burner combustion operation is instructed in accordance with the start of printing, the burner 18 starts combustion according to the instruction degree, and the burner 18 starts combustion according to the instruction degree, and the burner opening is 0 or between the bottom combustion opening V0 and the maximum combustion opening 100%. This controls the opening degree.

As shown in the graph of FIG. 2, the drying device of the present invention has a burner 1
For both 8 and 19, the minimum combustion opening degree V0 (e.g. 25%)
combustion (initial combustion). Then, when printing is started, the paper surface temperature setting section 17 sends a signal in response to the measured value of the paper surface thermometer 16, and the first
When the opening degree of the burner 18 in the drying zone increases from the minimum combustion opening degree V0 and eventually reaches a predetermined amount V1 (V1>V0), the switch mechanism is activated to control the opening and closing of the burner 19. A control operation by the device is started. And burner 18
When the opening degree of the burner 19 reaches 100% and the opening degree of the burner 19 reaches a predetermined amount V2 (for example, 75%), the switch mechanism is activated and the control operation of the opening/closing control device of the burner 18 is stopped. The opening/closing control device continues its control operation, and the opening degree of the burner 19 eventually reaches 100%. In this way, the burner 19 follows the burner 18. This is a control operation in the increasing direction throughout, but the control operation in the decreasing direction is the opposite.

There are various switching mechanisms for operating or stopping the opening/closing control devices of the burners 18 and 19, but any switch mechanism may be used as long as it does not deviate from the control operation of the present invention. For example, the opening/closing control device for one burner 18 is provided with a normally closed switch (b contact switch) that opens when the opening degree of the burner 18 reaches 100% and the opening degree of the burner 19 reaches V2 or more, and By providing the opening/closing control device for the burner 19 with a normally open switch (a contact switch) that closes when the opening degree of the burner 18 reaches V1 or more, it is possible to perform control operations for switching between operation and stop. can.

As a result, the temperature of the first drying zone rises, and the fan 20 blows hot air onto the printed paper surface.

The heated air in the first drying zone is not directly exhausted, but is sent into the second drying zone through the ventilation pipe 3 by closing the damper 11 and opening the damper 15. In general, exposing the printing paper surface to higher temperatures than necessary for a long time will cause wrinkles, blisters, etc., which is unfavorable in terms of print quality.
After the paper is momentarily heated to a high temperature in the drying zone, hot air at a temperature lower than that in the first drying zone is blown onto the printing paper in the second drying zone, so that the temperature of the ink surface permeates into the inside of the ink. In one embodiment of the invention, the temperature in the first drying zone is 240°C and the temperature in the second drying zone is 240°C.
The temperature is 200℃. For this reason, as shown in FIG. 2, the burner 19 is set to open with a delay compared to the burner 18, and even when the amount of ink on the printed paper is small and only the burner 18 is burned, the paper surface temperature is set. If the temperature reaches that temperature, the burner 19 should not be opened and only the heated air sent from the first drying zone should be blown onto the printed paper surface. Furthermore, even when more thermal energy is required, the opening degree of the burner 19 can be kept small, resulting in less combustion consumption.

In this way, the air heated for drying the printing paper in the first and second drying zones is transferred to the exhaust duct 1 by opening the dampers 12 and 14.
0 and 13, and is sent to a deodorizing device (not shown). Note that the exhaust pipe 9 is used with the damper 11 opened only when the concentration of the ink solvent component increases to a higher level because the amount of evaporation of the ink solvent is large in the first drying zone. However, some of the hot air is sent directly to the deodorizing equipment.

In the above description, the drying device according to the present invention is installed in parallel with an offset rotary press to dry the printed paper after printing is completed. The present invention is not limited to printing paper, and can be applied to drying various continuous materials such as plastics coated with paints or coatings, metal films, fibers, and cloth, in addition to printing paper.

As described above, according to the present invention, the first and second
a drying zone is provided, the first drying temperature is set to a high temperature,
By setting the second drying zone at a relatively low temperature, the material to be dried is rapidly dried in the first drying zone, and then the second drying zone removes the high heat on the surface of the part to be dried. Since the temperature can be set so that the water gradually penetrates into the interior, it is possible to prevent stress caused by rapid cooling of the printed matter after leaving the drying device, compared to, for example, a heating drying operation using only one drying zone. Printed matter is less likely to suffer from quality deterioration due to high heat, wrinkles, blisters, or other unfavorable reductions in print quality.

In addition, the first
The combustion state of the second drying zone is controlled, and the heating device of the second drying zone is set to operate following the heating device of the first drying zone, so thermal energy can be effectively used. can be used, and combustion consumption can be kept to a minimum.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is an explanatory diagram schematically showing the structure of the drying device, and FIG. 2 is a graph showing the relationship between the combustion instruction degree and the combustion opening degree of the heating device. be. DESCRIPTION OF SYMBOLS 1... Peripheral wall, 2... Partition wall, 3... Ventilation pipe, 4... Printing, 5... Printing paper outlet, 16... Paper thermometer, 17...
Paper surface temperature setting section, 18, 19...burner, 20,
21...Fan, a...A contact switch, b...B contact switch,...first drying zone,...second drying zone, W...printing paper.

Claims (1)

[Claims] 1 A first drying zone and a second drying zone separated by a partition wall.
drying zones are arranged in sequence in the flow direction of the material to be dried, a burner heating device and a blower device are installed in each of the first drying zone and the second drying zone, and the material to be dried in the second drying zone is A paper thermometer 16 is provided on the exit side, and the burner 18 of the first drying zone and the burner 18 of the second
A burner opening/closing control device is provided that drives the opening degree of the burner 19 in the drying zone in the direction of increasing or decreasing, respectively, and controls the burner opening degree between 0 or the minimum combustion opening degree V0 and the maximum combustion opening degree of 100%. In the drying device, the switch mechanism controls the opening/closing control device of the other burner 19 when the opening degree of the one burner 18 is equal to or higher than a predetermined amount V1 (V1>V0), and the opening degree of the one burner 18. but
100%, the opening degree of the other burner 19 is a predetermined amount
When V2 (V2>V1) or higher, one of the burners 1
8. A drying device characterized by being provided with a switch mechanism for stopping the control operation of the opening/closing control device.