JP4800087B2 - Hot air dryer for printing paper - Google Patents

Description

  The present invention relates to an apparatus for drying printing paper with hot air.

  In the web printing line, a high-speed offset printing machine, a hot-air drying device, a cooling device, and a folding machine are sequentially arranged. In a printing machine, a strip-shaped paper drawn from a web is passed through a printing roller and printed with ink. The strip-shaped printing paper that has passed through the printing machine is heated by passing the hot air in the hot air drying device, and the printing ink adhering to the paper surface is dried. The strip-shaped printing paper that has passed through the drying device passes through the cooling roller of the cooling device and is cooled. The strip-shaped printing paper that has passed through the cooling device is folded in a folder.

  The hot air drying device has a drying chamber between the printing press and the cooling device. The drying chamber has a box shape that is long in the front-rear direction. This drying chamber has a horizontally long rectangular inlet on the front end wall, a horizontally long rectangular outlet on the rear end wall, and forms a printing paper passage from the inlet to the outlet. After the band-shaped printing paper passes through the printing press, it sequentially passes through the inlet of the drying chamber, the printing paper passage and the outlet, and reaches the cooling device.

  The drying chamber is provided with a number of nozzles that blow hot air up and down across the printing paper path in the front-rear direction. When the strip-shaped printing paper passes through the printing paper path in a horizontal state, hot air blown from the nozzles hits the upper and lower surfaces, respectively, and the solvent of the printing ink adhering to the upper and lower surfaces evaporates. The printing ink on the upper and lower surfaces dries.

  The nozzle is connected to the hot air supply path. The hot air supply path sequentially connects the blower, the heating device, and the nozzle. The air in the drying chamber and hot air blown from the nozzle are heated through a blower and a heating device and supplied to the nozzle.

  A purification discharge path is connected to the drying chamber. The purification discharge path sequentially connects the blower, the heat receiving passage of the heat exchanger, and the purification device and the heat dissipation passage of the heat exchanger. The purification device is a deodorizing device including a heating device and an oxidation catalyst. The heat exchanger is for heating the exhaust before heating the exhaust before purification with the heat and exhaust heat of the high-temperature exhaust after purification. The hot air in the drying chamber and the hot air including the solvent vapor of the printing ink are deodorized and purified through the blower, the heat receiving passage of the heat exchanger and the purification device, and become high-temperature exhaust. The high-temperature exhaust gas after purification is discharged to the atmosphere through the heat dissipation passage of the heat exchanger.

  In the drying chamber, part of the hot air in the room is released to the atmosphere through the purification discharge path, and the room becomes negative pressure. Outdoor fresh air is drawn into the negative pressure drying chamber from the inlet and the outlet, respectively.

JP 2004-330560 A

[Issues of background technology]
1) In the hot air drying apparatus for printing paper as described above, the consumption of heat energy increases as the temperature difference between the exhaust gas flowing out from the drying chamber through the purification discharge passage and the air flowing into the drying chamber through the inlet increases. The amount increases.

  In the conventional hot air drying apparatus, the exhaust gas flowing out from the purification discharge passage is at a high temperature of about 200 ° C., and the air flowing in from the inlet is at a room temperature of about 20 ° C. In the drying chamber, the temperature difference between the outflow exhaust gas and the inflow air is about 180 ° C., and the consumption of heat energy is large. Energy saving is desired.

  2) In the drying chamber, the solvent vapor of printing ink drifts, and air flows into the drying chamber. The air has a room temperature of about 20 ° C. When the solvent vapor in the drying chamber is cooled by contact with air at room temperature, it condenses and tarizes. Printing paper that runs near the entrance of the drying chamber and the vicinity of the entrance of the drying chamber may become dirty with solvent tar.

[Idea for solving problems]
1) In the hot air drying apparatus for printing paper, the air flowing into the drying chamber from the inlet is replaced with heated air or high temperature after purification flowing out to the atmosphere from the purification discharge passage of the drying chamber instead of room temperature air or non-heated air. I decided to make the air heated by exhaust. In the drying chamber, the temperature of the air flowing in from the inlet increases, and the temperature of the exhaust gas flowing out from the purification discharge path decreases. The temperature difference between the outflow exhaust and the inflow air is small. The consumption of heat energy is reduced.

  Further, the air flowing into the drying chamber from the inlet becomes heated air or hot air having a temperature higher than room temperature, and the solvent vapor of the printing ink is difficult to tar. There is less possibility that the vicinity of the entrance of the drying chamber or the printing paper is stained with solvent tar.

  2) Specifically, a hot air chamber is provided adjacent to the front side of the drying chamber. The hot air chamber is provided with an inlet and an outlet at the front and rear, similar to the inlet and outlet of the drying chamber. The outlet of the hot air chamber communicates with the inlet of the drying chamber. After the printing paper passes through the printing press, it passes through the hot air chamber from the inlet to the outlet and enters the inlet of the drying chamber.

  A hot air supply path is connected to the hot air chamber. The hot air supply path connects the blower and the heat receiving passage of the heat exchanger for generating hot air, and opens the upstream end to the atmosphere. The heat radiation passage of the heat exchanger for generating hot air is connected to the purification apparatus downstream side portion of the purification discharge path of the drying chamber. The fresh air near the upstream end and the open end of the hot air supply path is heated by the high-temperature exhaust gas in the purification discharge path via the hot air supply path, and is supplied as hot air to the hot air chamber. Then, hot air in the hot air chamber is sucked into the drying chamber from the entrance. Hot air flows into the drying chamber from the entrance.

  3) In the hot air chamber, the indoor pressure increases as the supply flow rate of hot air from the hot air supply passage increases. When the pressure of the hot air chamber becomes higher than the atmospheric pressure or the atmospheric pressure, the hot air flows out from the inlet of the hot air chamber. A printing press is located in front of the hot air chamber. When hot air flows out from the entrance of the hot air chamber, the printing press is exposed to the hot air and is adversely affected.

  Conversely, in the hot air chamber, when the supply flow rate of hot air from the hot air supply path decreases, the temperature of the indoor space decreases and the temperature of the hot air flowing into the drying chamber from the inlet decreases. Further, in the hot air chamber, when the hot air supply flow rate decreases, the pressure in the chamber decreases, the pressure difference from the drying chamber decreases, and the flow rate of hot air flowing into the drying chamber from the inlet decreases. Energy saving effect is reduced.

  Therefore, the hot air supply flow rate in the hot air supply path is controlled according to the pressure of the hot air chamber, and the pressure of the hot air chamber is maintained almost the same as the atmospheric pressure and the atmospheric pressure outside the room.

1) drying chamber provided inlet mouth and outlet, forms the print paper path from the inlet to the outlet, the strip of printed paper, the inlet of the drying chamber, sequentially passing through the printing paper passageway and the outlet, during running printing paper passage The printing paper is heated with hot air to evaporate the solvent of the printing ink, and the hot air drying device for printing paper is provided with a purification discharge passage that purifies the hot air containing solvent vapor in the drying chamber and discharges the high-temperature exhaust gas after purification to the atmosphere. In
A hot air chamber is provided in front of the drying chamber, the hot air chamber has an inlet and an outlet, the outlet of the hot air chamber communicates with the inlet of the drying chamber, and the printing paper passes through the hot air chamber from the inlet to the outlet to enter the drying chamber. In the composition
A hot air supply passage is provided for supplying fresh air to the hot air chamber by heating with high temperature exhaust gas after purification of the purification exhaust passage, and the hot air in the hot air chamber flows into the drying chamber from the inlet of the drying chamber,
A detector for detecting the pressure of the hot air chamber is provided, and a control device for controlling the hot air supply flow rate in accordance with the detected pressure of the detector is provided to maintain the pressure of the hot air chamber substantially the same as the outdoor air pressure. It is characterized by having a configuration .

2 ) In the hot-air drying apparatus for printing paper,
The hot air chamber is provided between the printing press and the drying chamber, and the belt-like printing paper fed from the printing press sequentially passes through the hot air chamber and the drying chamber.

  Fresh air is heated by the hot exhaust gas after purification and supplied to the hot air chamber, and the hot air in the hot air chamber flows into the drying chamber from the inlet. In the drying chamber, the temperature difference between the outflow exhaust gas and the inflow air becomes small, and the consumption amount of heat energy decreases.

  In addition, the air flowing into the drying chamber from the entrance becomes hot air having a temperature higher than room temperature, and the solvent vapor of the printing ink is hardly tarized near the entrance of the drying chamber.

  As shown in FIG. 1, the web printing line has a high-speed offset printer P, a hot air drying device D, a cooling device C, and a folding device F arranged in sequence. In the printing press P, although not shown, the belt-like paper is drawn out from the web placed on the paper feed unit, and the belt-like paper passes through the printing roller unit and is printed with ink. The strip-shaped printing paper a fed out from the printing press P at high speed passes through the hot air drying device D and is heated with hot air, and the printing ink adhering to the paper surface is dried. The strip-shaped printing paper a that has passed through the drying device D passes through the cooling roller of the cooling device C and is cooled. The strip-shaped printing paper “a” that has passed through the cooling device C is fed into the folding machine F, and is folded and folded at regular intervals.

  As shown in FIG. 1, the hot air drying device D includes a drying chamber 1 between the printing press P and the cooling device C. The drying chamber 1 has a box shape that is long in the front-rear direction. This drying chamber 1 is provided with a horizontally-long rectangular inlet 2 on the front end wall and a horizontally-long rectangular outlet 3 on the rear end wall at the same height, and the printing paper passage 4 is horizontally arranged in the front-rear direction from the inlet 2 to the outlet 3. Forming. The strip-shaped printing paper a delivered from the printing press P sequentially passes through the inlet 2 of the drying chamber 1, the printing paper passage 4 and the outlet 3, and is sent from the drying chamber 1 to the cooling device C.

  The drying chamber 1 is provided with a number of nozzles 6 for blowing hot air toward the printing paper path 4 above and below the printing paper path 4 in the front-rear direction. A large number of nozzles 6 are arranged in a staggered manner across the printing paper path 4. When the belt-shaped printing paper a passes through the printing paper passage 4 in a horizontal state, hot air blown from the nozzle 6 hits the upper and lower surfaces, respectively, and the solvent of the printing ink adhering to the upper and lower surfaces evaporates. The printing ink on the upper and lower surfaces dries.

  Each nozzle 6 is connected to a hot air supply path. The hot air supply path sequentially connects the blower 7, the heating device 8, and the nozzle 6. The blower 7 opens the suction port into the drying chamber 1. In the hot air supply path, the air in the drying chamber 1 and the hot air blown from the nozzle 6 sequentially pass through the blower 7 and the heating device 8 and are heated and supplied to the nozzle 6.

  A purification discharge path is connected to the drying chamber 1. The purification discharge path sequentially connects the blower 11, the heat receiving passage of the heat exchanger 12, and the purification device 13 and the heat dissipation passage of the heat exchanger 12. The blower 11 connects the suction port to the drying chamber 1 through the upstream end portion of the purification discharge path. The heat exchanger 12 opens its heat radiation passage to the atmosphere through the downstream end portion of the purification discharge passage. The purification device 13 is a deodorizing device including a heating device and an oxidation catalyst. The heat exchanger 12 is for exhaust heating that heats the exhaust before purification with the heat and exhaust heat of the high-temperature exhaust after purification. In the purification discharge path, the hot air in the drying chamber 1 and the hot air including the solvent vapor of the printing ink sequentially pass through the blower 11 and the heat receiving passage of the heat exchanger 12 and the purification device 13, are deodorized and purified, and are exhausted at a high temperature. become. The high-temperature exhaust gas after purification passes through the heat dissipation passage of the heat exchanger 12 and is released to the atmosphere.

  As shown in FIG. 1, a hot air chamber 21 is provided adjacent to the front side of the drying chamber 1 between the printing press P and the drying chamber 1. The hot air chamber 21 has a box shape, and the front end wall of the drying chamber 1 is also used as a rear side wall. This hot air chamber 21 is provided with a horizontally-long rectangular inlet 22 on the front side wall and a horizontally-long rectangular outlet 23 on the rear side wall at the same height, and horizontally forms a printing paper path from the inlet 22 to the outlet 23. ing. The printing paper path of the hot air chamber 21 is the same height as the printing paper path 4 of the drying chamber 1. The outlet 23 of the hot air chamber 21 communicates concentrically with the inlet 2 of the drying chamber 1. The inlet 2 of the drying chamber 1 is also used as the outlet 23 of the hot air chamber 21. The strip-shaped printing paper a delivered from the printing press P passes through the hot air chamber 21 from the inlet 22 to the outlet 23 and enters the inlet 2 of the drying chamber 1. The hot air chamber 21 and the drying chamber 1 are sequentially passed.

  A hot air supply path is connected to the hot air chamber 21. The hot air supply path connects the heat receiving passages of the blower 26, the heat exchanger 27, and the hot air generating heat exchanger 27. The blower 26 opens the suction port to the atmosphere via the upstream end portion of the hot air supply path. The heat receiving passage of the hot air generating heat exchanger 27 is connected to the hot air chamber 21 via the downstream end portion of the hot air supply path. The heat radiation passage of the heat exchanger 27 for generating hot air is connected to the downstream portion of the purification device 13 of the purification discharge passage and downstream of the heat radiation passage of the heat exchanger 12 for exhaust heating. In the hot air supply path, fresh air near the upstream end and the open end passes through the heat receiving passages of the blower 26 and the hot air generating heat exchanger 27 and is heated by the high-temperature exhaust gas after purification in the purification discharge path to become hot air. The hot air chamber 21 is supplied.

  The flow rate of hot air supplied from the hot air supply path to the hot air chamber 21 is controlled by the blower 26. An induction motor 31 that rotationally drives the blower 26 is connected to an AC power source 33 via a variable voltage variable frequency device 32 called an inverter. The hot air chamber 21 is provided with a detector 36 for detecting the pressure in the chamber and a pressure detector 36. A control device 37 that outputs a speed command signal in accordance with the input value is provided. The control device 37 has a pressure detector 36 connected to the input end, and an output end connected to the command receiving terminal of the variable voltage variable frequency device 32. The control device 37 controls the rotation speed of the induction motor 31 and the rotation speed of the blower 26, that is, the supply flow rate of hot air, according to the detected pressure of the detector 36, and the pressure of the hot air chamber 21 is increased to the atmospheric pressure, Maintain almost the same as atmospheric pressure. Constant value control is performed to maintain the pressure of the hot air chamber 21 within the range of atmospheric pressure ± a small amount.

  When the hot air drying device D is operated, the blower 11 and the purification device 13 in the purification discharge path are operated, and the blower 7 and the heating device 8 in the hot air supply path are operated. Further, the blower 26 in the hot air supply path is operated. When the printing line is operated, the printing paper a that has passed through the printing press P passes through the hot air chamber 21 from the inlet 22 to the outlet 23, and passes through the drying chamber 1 from the inlet 2 to the outlet 3.

  In the drying chamber 1, part of the hot air in the room is released to the atmosphere through the purification discharge path, and the room becomes negative pressure. The hot air chamber 21 is supplied with hot air from the hot air supply path, the hot air supply flow rate is controlled, and the indoor pressure is maintained substantially the same as the outdoor atmospheric pressure and the atmospheric pressure. Hot air in the hot air chamber 21 at approximately atmospheric pressure is sucked into the negative pressure drying chamber 1 from the inlet 2, and fresh outdoor air is sucked in from the outlet 3. A small amount of fresh air accompanying the printing paper a flows into the hot air chamber 21 from the inlet 22.

In the hot air drying apparatus D of the embodiment, in the drying chamber 1, the air inflow amount from the inlet 2 and the air inflow amount from the outlet 3 are respectively about half of the air outflow amount from the purification discharge path. When the air outflow amount of the purification discharge path is 50 m ³ N / min, the air inflow amount at the inlet 2 and the air inflow amount at the outlet 3 are about 25 m ³ N / min, respectively. Moreover, the drying chamber 1 has a high temperature at which the air flowing out from the purification discharge path to the atmosphere is a little less than 200 ° C. The air flowing in from the inlet 2 is as high as about 80 ° C. The air flowing in from the outlet 3 has a room temperature of about 20 ° C.

  The temperature difference between the outflow air of the purification discharge passage and the inflow air of the inlet 2 is about 120 ° C. (approximately 200 ° C.−80 ° C. =). Conventionally, this temperature difference is about 180 ° C. The amount of decrease in the temperature difference is about 180 ° C.−120 ° C. = 60 ° C. This amount of decrease is substantially the same as the amount of increase in the temperature of the air flowing into the inlet 2 in the embodiment, about 80 ° C.−20 ° C. = 60 ° C. This amount of change in temperature, the amount of decrease in heat energy consumption based on about 60 ° C., is the amount of saved heat energy in the embodiment. This saved heat energy is as follows.

[Inlet 2 air inflow rate, 25 m ³ N / min × 60 min / h] × [Inlet 2 air density, 1.2 kg / m ³ ] × [Inlet 2 air specific heat capacity, 1.0 J / (kg · ° C. )] × [Temperature change, 60 ° C.] = 108000 J / h

[Modification]
1) In the above embodiment, the heat release passage of the hot air generating heat exchanger 27 is connected to the downstream side portion of the heat release passage of the exhaust heating heat exchanger 12 of the purification discharge passage. 13 is a downstream portion, which is connected to the upstream side portion of the heat radiation passage of the heat exchanger 12 for exhaust heating.
2) In the above embodiment, the rotation speed changing device and the transmission device of the blower 26 in the hot air supply path are the variable voltage variable frequency device 32 of the inverter, but other electric transmission devices are used. Alternatively, a mechanical transmission is used.

The schematic diagram of the hot air drying apparatus of the printing line in the embodiment of the present invention, and its vicinity.

Explanation of symbols

P high-speed offset printing machine, printing machine D hot air drying device C cooling device F folding machine a strip-shaped printing paper, printing paper 1 drying chamber 2 drying chamber inlet 3 drying chamber outlet 4 drying chamber printing paper path 6 drying chamber Nozzle, nozzle of hot air supply path 7 blower of hot air supply path 8 heating device of hot air supply path 11 fan of purification discharge path 12 heat exchanger of purification discharge path, heat exchanger for exhaust heating 13 purification apparatus of purification discharge path, deodorization Device 21 Hot air chamber 22 Hot air chamber inlet 23 Hot air chamber outlet 26 Hot air supply passage blower 27 Hot air supply passage heat exchanger, hot air generation heat exchanger 31 Induction motor 32 for driving the blower Inverter, variable voltage variable frequency device 33 AC power source 36 Detector for detecting pressure in hot air chamber, pressure detector, detector 37 Control device, constant value control device

Claims (2)

Drying chamber provided inlet mouth and outlet, forms the print paper path from the inlet to the outlet, the strip of printed paper, the inlet of the drying chamber, sequentially passes through the printed sheet passage and an outlet, the hot air during running printing paper passage In the hot air drying apparatus for printing paper provided with a purification discharge path that purifies the hot air containing solvent vapor in the drying chamber and releases the high-temperature exhaust gas after purification to the atmosphere
A hot air chamber is provided in front of the drying chamber, the hot air chamber has an inlet and an outlet, the outlet of the hot air chamber communicates with the inlet of the drying chamber, and the printing paper passes through the hot air chamber from the inlet to the outlet to enter the drying chamber. In the composition
A hot air supply passage is provided for supplying fresh air to the hot air chamber by heating with high temperature exhaust gas after purification of the purification exhaust passage, and the hot air in the hot air chamber flows into the drying chamber from the inlet of the drying chamber,
A detector for detecting the pressure of the hot air chamber is provided, and a control device for controlling the hot air supply flow rate in accordance with the detected pressure of the detector is provided to maintain the pressure of the hot air chamber substantially the same as the outdoor air pressure. A hot-air drying apparatus for printing paper, characterized in that it is configured . 2. The printing paper according to claim 1, wherein the hot air chamber is provided between the printing machine and the drying chamber, and the belt-like printing paper fed from the printing machine sequentially passes through the hot air chamber and the drying chamber. Hot air drying device.

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