JPH04305455A - Apparatus for controlling temperature of dryer for rotary press - Google Patents

Abstract

PURPOSE:To provide the title apparatus rapidly and accurately preventing the temp. rise of a paper surface at the time of a decrease in a printing speed. CONSTITUTION:In the dryer of a printing machine equipped with a direct combustion type deodorizing apparatus, a heat recovery apparatus 9 heating the hot air in a dryer by the exhaust gas of said apparatus 8 and the bypass line 20 bypassing the heat recovery part of the heat recovery apparatus to be connected to a hot air nozzle and having a damper 21 controlled on the basis of the surface temp. of printing paper to be opened and closed, a bypass line 31 bypassing the heat recovery apparatus 9 to be connected to a discharge part and having a damper 33 controlled on the basis of the surface temp. of the printing paper to be opened and closed is provided to the line supplying exhaust gas to the heat recovery apparatus 9.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature control device for a dryer for a rotary printing press.

0002

2. Description of the Related Art A conventional drying device (dryer) for a rotary printing press will be explained with reference to FIG. In FIG. 4, 1 is the main body of the drying device, 2 is the printed paper, and 3 is the main body 1 of the drying device.
4 is a hot air heating burner, 5 is a blower for the first zone, 6 is a blower for the second zone,
7 is an exhaust gas blower, 8 is a deodorizing device, the printing paper 2 printed by the printing machine is guided into the drying device main body 1, and the burner 4
The hot air is blown onto the printing paper 2 through the hot air blowing nozzle 3, and the ink solvent evaporates. Further, the hot air blown from the hot air blowing nozzle 3 into the drying device main body 1 and hitting the printing paper 2 returns to the suction side of the first zone blower 5 and the second zone blower 6, and is reheated by the burner 4. , is sent to the hot air blowing nozzle 3. Also, a part of this hot air is sucked by the exhaust gas blower 7 and guided to the deodorizing device 8, where it is deodorized by a catalytic reaction.
A portion is returned into the drying device main body 1, and the remainder is released into the atmosphere. Further, from the viewpoint of pollution prevention, the inside of the drying device main body 1 is kept under negative pressure to prevent hot air (exhaust gas) inside the drying device main body 1 from being discharged to the outside.

Recently, a dryer as shown in FIG. 3 has been proposed in Japanese Patent Application No. 02-152548 with the aim of saving energy, being compact, and improving temperature controllability. In Fig. 3, 1 is the main body of the drying device, 2 is the printing paper, 3 is the hot air blowing nozzle, 4 is the preheating burner, 5 is the blower for the first zone, 6 is the blower for the second zone, 7 is the exhaust gas blower, and 8 is the direct blower. Combustion type deodorizing device, 9 is a heat recovery device, 10 is a deodorizing burner, 11 is a preheater, 12 is a direct combustion reactor, 20 is a bypass line, 21 is an automatic bypass damper, 22 is a damper driving motor (or cylinder ), 23 is a function generator, 24
2 is a deodorizer furnace temperature detector, 25 is a first zone hot air temperature detector, and 26 is a paper surface temperature detector. 27 is a paper surface temperature control device, and 28 is a deodorizer furnace temperature control device.

At the start of operation before normal operation, the exhaust gas blower 7 is operated to suck outside air (combustion air) into the drying device main body 1, and the outside air sucked into the drying device main body 1 is operated by the exhaust gas blower 7. → Inside the heat exchanger tube of the preheater 11 → Direct combustion reaction 12 → Outside the heat exchanger tube of the preheater 11 → Guided into the heat exchanger tube of the heat recovery device 9. In addition, the first zone blower 5 and the second zone blower 6 are operated to circulate the outside air sucked into the drying device main body 1 into the drying device main body 1, and then the preheating burner 4 is ignited and burned. , heats the air circulating within the drying device main body 1. In addition, the air in the drying device main body 1 is guided as combustion air from the exhaust gas blower 7 to the heat exchanger tube of the preheater 11 to the direct combustion reactor 12, and the fuel from the deodorizing burner 10 is ignited and burned. At this time, the generated exhaust gas is guided from the outside of the heat transfer tube of the preheater 11 to the inside of the heat transfer tube of the heat recovery device 9, and after preheating the air circulating inside the drying device main body 1 as described above, it is passed outside the drying device main body 1. Discharge. As a result, the temperature of the circulating air within the drying device main body 1 quickly rises to a predetermined temperature at the start of operation before normal operation.

[0005] When this state is reached, the preheating burner 4 is stopped and normal operation begins. At this time, the printing paper 2 printed by the rotary printing machine is guided into the drying device main body 1, and hot air is blown from the hot air blowing nozzle 3 into the printing paper path, hitting the printing paper 2, and ink on the printing paper 2. While evaporating the solvent contained in the evaporated solvent, the hot air (exhaust gas at about 140 to 170°C) containing the evaporated solvent is transferred to the heat recovery device 9 which is the suction side of the first zone blower 5 and the second zone blower 6. The exhaust gas passing through the inside of the heat exchanger tube of the heat recovery device 9, that is, the exhaust gas from the direct combustion reactor 12 of the direct combustion deodorizing device 8 (exhaust gas at about 400 to 500°C), returns to the outside of the heat exchanger tube. Reheat to ~250℃,
Send it to hot air blowing nozzle 3. Further, a part of the hot air in the drying device main body 1 is sucked by the exhaust gas blower 7 and guided into the preheater 11 of the direct combustion type deodorizing device 8, where it is preheated by the exhaust gas from the direct combustion type reactor 12. Direct combustion reactor 12
That is, the hot air is guided to a direct combustion reactor 12 heated to about 700 to 1000°C by a deodorizing burner 10, the evaporated solvent in the hot air is burned, the hot air is deodorized, and the exhaust gas generated at this time is heat recovered. After being led into the heat exchanger tube of the device 9 and performing the above heat exchange, it is discharged to the outside of the drying device main body 1.

[0006] Furthermore, a bypass line 20 is provided in the first zone hot air circulation line, and an automatic bypass damper 21 is provided in the middle of the line 20. The paper surface temperature control device 27 is linked to the motor 22 (or cylinder) attached to the automatic bypass damper 21 and the starting preheating burner 4, and sends a control signal. That is, the paper surface temperature control device 27 performs, for example, a PID calculation so that the paper surface temperature detection value obtained from the paper surface temperature detection value 26 becomes equal to a predetermined target value, and outputs the calculation result Cv. Converters 29 and 30 perform the calculations shown in FIGS. 5 and 6 according to Cv, and send opening command signals to preheating burner 4 or motor 22, respectively.

[0007] Also, the deodorizer furnace temperature control device 28 has a first
Deodorizer furnace temperature detector 24
Burner 1 for deodorization so that the temperature inside the furnace reaches the specified temperature.
The combustion amount of 0 is controlled. Note that an example of the calculation contents of the calculation unit 23 is shown in FIG.

[0008]

SUMMARY OF THE INVENTION The above-mentioned prior art has the following problems. In FIG. 3, the hot air rise response at the time of startup is such that the temperature can be raised to a predetermined value in about one minute using the preheating burner 4. However, when the drying heat load decreases, especially when the printing speed decreases during normal operation, the paper surface temperature increases. Therefore, the paper surface temperature control device 27 attempts to lower the hot air temperature by operating the opening degree of the bypass damper 21 in the opening direction. However, the bypass flow rate flowing into the bypass line 20 cannot be 100% in order to thermally protect the heat exchanger tubes of the heat recovery device 9. That is, even if the bypass damper opening degree is 100%, a portion of the heat also flows to the heat recovery device 9. Since the heat capacity of the heat transfer tube of the heat recovery device 9 is large and heat is continuously supplied from the high temperature side of the heat recovery device 9, the temperature of the hot air passing through the heat recovery device 9 is until then, that is, the amount of bypass = 0. It's higher than when it was.

[0009] Therefore, if it merges with the hot air from the bypass line, a sufficient bypass effect cannot be obtained and the hot air temperature lowering effect is poor. In other words, the responsiveness of the paper surface temperature is poor. As a result, the quality of the paper exiting the dryer is poor, resulting in a large amount of wasted paper. SUMMARY OF THE INVENTION An object of the present invention is to provide a temperature control device for a dryer for a rotary printing press that quickly and reliably prevents a rise in paper surface temperature when the printing speed decreases.

0010

[Means for solving the problem] (1) A bypass line 20 is connected to the heat recovery device 9 which is a heat supply source of hot air as shown in FIG.
In addition to providing a bypass line (
B). (Note that the conventional bypass line 20 is referred to as a bypass line (A).) (2) A damper is provided in each of both bypass lines.

(3) A paper surface temperature control device that controls the detected value from the printed paper surface temperature sensor to a predetermined target value opens both bypass dampers provided in the above (2) when the temperature drops, and opens the conventional bypass dampers when the temperature rises. Similarly, the combustion amount of the preheating burner 4 is controlled. (4) The specifications of the exhaust fan 7, which conventionally had a constant rotation speed, are changed to a fan whose rotation speed can be changed, and a dryer internal pressure control device is provided that controls the dryer internal pressure by controlling the rotation speed of the exhaust fan. (5) A calculator is provided to calculate the additional amount of the dryer internal pressure setting value according to the deviation of the paper surface temperature. (6) An adder is provided that adds the normally constant dryer internal pressure target value and the output of the calculator and outputs the result as the dryer internal pressure setting value from the dryer internal pressure control device.

0012

[Operation] Three operation ends (bypass (A) damper, bypass (B) damper, preheating burner) are operated by the paper surface temperature control device. Therefore, the opening command value of the bypass (B) damper should be the same value as the bypass (A) damper, or
Alternatively, a bypass (B) damper computing unit may be installed separately from the computing unit shown in FIG. (For example, use a polygonal line instead of a straight line as shown in Figure 5.

Now, when the printing speed decreases, the value detected by the paper surface temperature detector increases, so the paper surface temperature control device operates both bypass dampers in the opening direction by PID calculation to adjust the temperature of the hot air blown out from the nozzle. Lower it. Since the heat supply side of the heat recovery device 9 is also bypassed, the responsiveness of the hot air temperature drop is better than before. Further, in accordance with the paper surface temperature deviation (that is, paper surface temperature detection value - target value), the pressure setting value in the dryer is lowered (because it is originally a negative pressure) and the amount of infiltrated air is increased, thereby quickly lowering the hot air temperature.

[0014]

Embodiment A first embodiment of the present invention will be described with reference to FIG. In the figure, 1 is the dryer main body, 2 is the printing paper, 4 is the preheating burner, 8 is the direct combustion type deodorizing device, 9 is the heat recovery device,
10 is a deodorizing burner, 26 is a paper surface temperature detector, 27 is a paper surface temperature control device, 28 is a deodorizing device furnace temperature control device, 2
4 is a deodorizing equipment furnace temperature detector, 20 is a bypass line (
A), 21, 33 are dampers, 31 is a bypass line (B
), 23, 29, 30, and 43 are computing units, and 25 is a hot air temperature detector.

In this embodiment, a conventional bypass line (A
) 20, a bypass line (B) 31 is also provided on the heat supply side of the heat recovery device 9, and a damper driving motor 32 and a damper 33 are provided in the middle of the bypass line (B) 31. Arithmetic units 29 and 30 perform the arithmetic operations shown in FIGS. 5 and 6 described above. Further, the arithmetic unit 43 is basically the same as the arithmetic unit 30, but its calculation content is different from that in FIG. 6, and for example, it can be made into a polygonal line.

That is, the output C of the paper surface temperature control device 27
When v is Cv>Cv*, the bypass (A) and (B) damper openings remain at 0%, and the preheating burner valve opening opens and closes. Also, when Cv<Cv*, preheating burner valve opening = 0%
(In other words, the fire is extinguished), the bypass (A) and (B) damper openings open and close. Next, a second embodiment of the present invention will be described with reference to FIG.

[0017] As members added to the first embodiment, 7
is an exhaust fan, 41 is a printing speed detector, 35 is a dryer internal pressure detector, 34 is a dryer internal pressure control device, 36 is a fan rotation speed controller, 37 is a dryer internal pressure target value (constant value), and 38 is a calculation 39 is an adder. The second embodiment has the following functions in addition to the operations shown in FIGS. 5 and 6 and the opening and closing of the bypass (A) and (B) dampers described in the first embodiment.

The dryer internal pressure control device 34 controls the rotation speed of the exhaust fan 7 using the exhaust fan 7 rotation speed controller 36 so that the detected value from the dryer internal pressure detection value 35 becomes a predetermined value. The dryer internal pressure target value is usually a constant value 37
(negative pressure). As shown in FIG. 8, the calculator 38 calculates the additional amount of the dryer internal pressure setting value (a negative number because it is a negative pressure) according to the paper surface temperature deviation (paper surface temperature detection value - target value). Note that ε in FIG. 8 indicates an allowable deviation. The adder 39 is the arithmetic unit 38
The output and the target value 37 are added and outputted to the dryer internal pressure control device 34 as a set value. As a result, when the printing speed decreases and the paper surface temperature increases, the pressure inside the dryer temporarily decreases, the amount of air entering increases, and the responsiveness of hot air temperature decrease increases.

[0019]

Effects of the Invention The temperature control device for a printing press dryer according to the present invention includes a direct combustion type deodorizing device, a heat recovery device that heats hot air in the dryer with the exhaust gas of the device, and a heat recovery section of the heat recovery device. In the dryer of a printing press, the bypass line is connected to a hot air nozzle and has a damper that opens and closes depending on the temperature of the printed paper surface. By providing a bypass line connected to the discharge section and having a damper that opens and closes under control of the printing paper surface temperature, the following effects can be obtained.

When the printing speed decreases, not only does the hot air bypass the heat recovery device that is the heat supply source, but also the exhaust gas from the heat supply side, that is, the deodorization device, also bypasses the heat recovery device. Therefore, it is possible to control the temperature drop of the hot air blown onto the printing paper with good responsiveness. As a result, it becomes possible to improve product retention, that is, to significantly reduce paper waste.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a second embodiment of the present invention.

FIG. 3 is a configuration diagram of a conventional device.

FIG. 4 is a configuration diagram of another conventional device.

FIG. 5 is a diagram showing the relationship between the paper surface temperature control device output and the preheating burner valve opening command value.

FIG. 6 is a relationship diagram between the paper surface temperature control device output and the bypass damper opening command value.

FIG. 7 is a diagram showing the relationship between the first zone hot air temperature and the deodorizing device furnace temperature setting value in the conventional device.

FIG. 8 is a diagram showing the relationship between paper surface temperature deviation and dryer internal pressure set value addition amount.

[Explanation of symbols]

1 Dryer body 2 Printing paper 8. Direct combustion deodorization equipment 9 Heat recovery equipment 20 Bypass line (A) 26 Paper surface temperature detector 31 Bypass line (B) 33 Damper

Claims (2)

[Claims] Claim 1: A direct combustion type deodorizing device, a heat recovery device that heats hot air in a dryer with the exhaust gas of the device, and a heat recovery device that bypasses the heat recovery section of the heat recovery device and is connected to a hot air nozzle, and is connected to a hot air nozzle to reduce the temperature of the printed paper surface. In the dryer of a printing press equipped with a bypass line having a damper that opens and closes under control of 1. A temperature control device for a dryer for a rotary printing press, comprising a bypass line having a damper that opens and closes under control. 2. A direct combustion type deodorizing device, a heat recovery device that heats hot air in the dryer with the exhaust gas of the device, and a heat recovery device that bypasses the heat recovery section of the heat recovery device and connects to the hot air nozzle, and is connected to the hot air nozzle to reduce the temperature of the printed paper surface. In the dryer of a printing press equipped with a bypass line having a damper that opens and closes under control of a bypass line having a damper that opens and closes under the control of the printing paper, and a means for controlling the rotation speed of an exhaust fan that blows hot air to the deodorizing device to control the internal pressure of the dryer based on the temperature of the printed paper surface. A temperature control device for a dryer for a rotary printing press.