JP5004330B2 - Heat exchanger - Google Patents

Description

  The present invention relates to a heat exchanging device that enables combustion of fuel in a furnace installed in a casing to recover the heat of combustion exhaust gas after heat exchange in the casing.

  In the hot air heater for leaf tobacco dryers and agricultural houses, in the heat exchange device that is the unit, fuel such as kerosene and heavy oil is burned in the furnace by a burner, and taken into the casing by a blower in the heat exchange section The former exchanges heat with air, and the former supplies dry hot air from the blowout opening into the leaf tobacco drying chamber, and the latter supplies hot air from the blowout opening into the house. And in the said heat exchange apparatus, the high-temperature combustion exhaust gas after burning a fuel in a furnace and exchanging heat is induced | guided | derived to the outdoors through a chimney, and it is made to discharge | emit (for example, patent document 1, Patent Document 2).

Japanese Utility Model Publication No. 63-32259 Japanese Patent Publication No. 5-28571

  Due to soaring fuel costs such as heavy oil and kerosene in recent years, the operating costs and heating costs of dryers have risen significantly, and leaf tobacco producers and horticultural farmers who operate these machines have been implementing energy-saving measures for existing facilities. There is a strong demand for it.

  However, in the conventional heat exchanging device, the heat of combustion of the fuel by the burner is exchanged with the air taken into the casing by the blower in the heat exchanging section to generate hot air, and the generated hot air is used for the leaf tobacco drying room or agriculture. Since it is a simple mechanism to be installed in the house, it was difficult to further improve the heat exchange efficiency.

  The present invention has been made in view of the above problems, and its purpose is to easily implement energy saving measures for existing dryers, etc., and to improve heat exchange efficiency with a relatively simple structure. An object of the present invention is to provide a heat exchange device that can save fuel.

In order to solve the above-mentioned problems, the heat exchange device according to claim 1 according to the present invention is provided with a furnace and a heat exchange part in a lower unit of a casing , a blower is arranged in an upper unit, and an intake of outside air in the upper unit. In the heat exchanging device provided with a circulation port through which the circulating air from the opening and the drying chamber attached is returned, and provided with a chimney that continues from the heat exchanging unit,
The chimney has an in-casing chimney extending from the heat exchanging portion extending horizontally in the lower unit directly below the blower to the side facing the circulation port in the vicinity of the blower and extending upward in the upper unit. ,
A screw plate for spirally guiding the exhaust gas after combustion is installed in the chimney portion in the casing extending upward in the upper unit , and a plurality of radiating fins are attached to the outer peripheral surface of the chimney portion in the casing,
The outside air and the circulating air taken into the upper unit are heated by the exhaust gas heat collected in the upper unit from the chimney portion in the casing and sent to the heat exchanging portion in the lower unit by a blower .

According to the heat exchange device of claim 1, the high-temperature combustion gas after the fuel is burned in the furnace by the burner is obtained from the outside air and the circulation port that are taken into the upper unit of the casing from the intake port in the heat exchange unit. After exchanging heat with the returned circulating air, it passes through the inside chimney portion extending upward in the upper unit continuing from the heat exchange portion as combustion exhaust gas, and is exhausted through the chimney portion outside the casing. At this time, the combustion exhaust gas flowing in the chimney part in the casing is guided in a spiral manner along the screw plate in the chimney part in the casing, so that it stays in the chimney part in the casing for a long time. The heat of the high-temperature combustion exhaust gas is efficiently recovered into the upper unit through the wall of the chimney in the casing . The mixed air of the outside air and circulating air were incorporated into the upper unit, after being preheated by the exhaust heat recovered in the upper unit, is fed to the heat exchanging portion of the lower unit by the blower, heat exchanger Therefore, the heat exchange efficiency in the heat exchange part is improved.

In addition, heat from the combustion exhaust gas in the chimney portion in the casing is transferred from the heat radiation fin to the inside of the upper unit by the plurality of heat radiation fins provided on the outer peripheral surface of the chimney portion in the casing in the upper unit . since heat is radiated to, from the casing chimney with improved heat transfer efficiency to the casing chimney outsiders, and improved recovery efficiency of the combustion exhaust gas heat, also the heat exchange in the lower unit by a blower by which The heat exchange efficiency in the heat exchange part of the air sent to the part is further improved.

According to the heat exchanger of the present invention, it is efficiently collected into the upper unit by a screw plate combustion exhaust gas heat is installed in a casing chimney in the upper unit in the casing chimney, the recovered waste heat, the upper The circulating air and fresh air taken into the unit are heated, and their temperature balance is made uniform. As a result, the temperature balance of the hot air generated by heat exchange is also made uniform. Thus, in the burner that performs the combustion control (on / off control, etc.) of the fuel according to the temperature of the hot air after the heat exchange, the combustion operation can be stabilized and the fuel can be saved.

As described above, according to the heat exchanging device according to the present invention, the exhaust gas after combustion is spirally formed in the chimney portion in the casing extending upward in the upper unit of the casing and in the vicinity of the blower and on the side facing the circulation port. In addition, a heat exchanger in the lower unit is installed after preliminarily heating the outside air and circulating air taken into the upper unit by installing a screw plate that guides the air and attaching a plurality of radiating fins to the outer peripheral surface of the chimney in the casing. because it was configured to feed the parts, the combustion exhaust gas heat after the heat exchange flowing casing chimney portion of the upper unit by the action of the screw plate and the heat radiating fins and collected efficiently in the upper unit, upper unit It can be heated mixing air of the outside air and circulating air in the inner, not the possible to improve the fuel economy of the heat exchange efficiency in the heat exchange section with An effect.

Further, according to the heat exchange device according to the present invention, since the screw plate is installed in the chimney portion in the casing in the upper unit , it is possible to easily implement energy saving measures for the existing heat exchange device. There is an effect.

Further, according to the heat exchange device according to the present invention, the combustion exhaust gas heat in the casing chimney in the upper unit efficiently recovered in the upper unit, it is possible to enhance the heat exchange efficiency of the heat exchange unit, the burner This has the effect of stabilizing the combustion operation and saving fuel.

  The best mode for carrying out the present invention will be described with reference to FIGS. In FIG. 1, 1 is a leaf tobacco dryer, 2 is a heat exchanger unit, and 3 is a drying chamber.

  As shown in FIG. 1, in the heat exchanging device unit 2, a furnace 6 including a burner 5 is disposed in the lower unit of the casing 4, and a blower 7 is disposed in the upper unit. One end of a heat exchanging portion 8 communicates with the upper portion of the furnace 6, and the heat exchanging portion 8 extends horizontally directly under the blower 7 and is connected to one end of the chimney portion 9 in the casing. The chimney portion 9 in the casing extends upward through the vicinity of the blower 7 and communicates with the chimney portion 10 outside the casing. The tip of the casing outer chimney 10 protrudes outdoors in the building B and is bent downward, and the combustion exhaust gas is exhausted to the outdoors from the lower end. A control panel 11 that controls the overall operation of the leaf tobacco dryer 1 is attached to the outside of the casing 4.

  The heat exchange unit 2 burns fuel (kerosene) in the furnace 6 by the burner 5, and the high-temperature combustion gas is taken into the casing 4 from the intake port 12 of the upper unit by the operation of the blower 7. Heat is exchanged with fresh air, thereby generating dry air (hot air), and the generated dry air is introduced into the lower pit 14 of the side drying chamber 3 from the outlet 13 of the lower unit. ing. On the other hand, the combustion gas in the furnace 6 is subjected to heat exchange in the heat exchanging unit 8 and then exhausted from the in-casing chimney 9 to the outdoor stack of the building B through the outer chimney 10 as combustion exhaust gas. ing. An intake damper 15 that adjusts the intake amount of fresh air into the casing 4 is attached to the intake port 12.

  As shown in FIGS. 1 and 2, a screw plate 16 for guiding combustion exhaust gas in a spiral manner is inserted and installed in the chimney portion 9 in the casing of the heat exchange unit 2. The screw plate 16 is for efficiently recovering the heat of the combustion exhaust gas after the heat exchange flowing inside the chimney portion 9 in the casing, and the combustion exhaust gas is transferred to the screw plate 16 in the chimney portion 9 in the casing. As a result, the combustion exhaust gas stays in the casing chimney 9 for a long period of time. As a result, the recovery efficiency of the high-temperature combustion exhaust gas heat after the heat exchange is increased. ing. And the air taken in in the casing 4 is heated by the exhaust heat collected in the upper unit of the casing 4 through the wall of the chimney part 9 from the chimney part 9 in the casing, and the heat in the heat exchange part 8 The exchange efficiency is also improved.

  A large number of circular (see FIG. 3) radiating fins 17 are attached to the outer peripheral surface of the chimney portion 9 in the casing at substantially equal intervals between the upper and lower ends of the chimney portion. The heat dissipating fins 17 increase the heat transfer area and the heat dissipating area of the outer peripheral surface of the chimney portion 9 in the casing, and the combustion exhaust gas heat in the chimney portion 9 in the casing is transmitted along the wall of the chimney portion 9 to the casing 4. The heat is dissipated in the interior, and the heat transfer efficiency from inside the chimney portion 9 in the casing to the outside of the chimney portion 9 in the casing is increased, and the recovery efficiency of the combustion exhaust gas heat is further enhanced. In addition to the circular shape, the shape of the radiating fin 17 includes a plate shape and a spiral shape.

  For the existing dryer 1, as shown in FIG. 4, a large number of radiation fins 17 are attached to the outer peripheral surface of the chimney unit 9A in the casing having a predetermined length, and a screw plate 16 is inserted and installed therein. This is manufactured in advance as an exhaust heat recovery device, and the existing chimney in the casing of the heat exchange device 2 is replaced with the manufactured exhaust heat recovery device. The required number of exhaust heat recovery units may be manufactured in advance, and can be easily replaced and installed on the existing dryer 1.

  The drying chamber 3 opens a sealed door (not shown) of the box-shaped container 18, and leaves the tobacco suspenders 19 packed with a large number of fresh tobacco leaves A with rollers (not shown) on both left and right ends of the container 18. It engages with two upper and lower guide rails (not shown) attached to the wall surface, sequentially moves to the back, hangs, and dries the fresh leaf tobacco A inside. In the lower part of the drying chamber 3, there is provided a rectifying plate 20 that forms a large number of holes 20 a with the lower pit 14, and this rectifying plate 20 rectifies the dry air blown out to the lower pit 14 and To create a uniform flow.

  A circulation port 21 is circulated in the upper portion of the side wall of the drying chamber 3 on the side of the heat exchanger unit 2 to circulate the dry air blowing up in the drying chamber 3 into the upper unit of the heat exchanger unit 2.

  Next, the operation method and exhaust heat recovery method of the leaf tobacco dryer 1 configured as described above will be described below.

  In the leaf tobacco dryer 1, the fuel is burned in the furnace 6 by the operation of the burner 5, and in the heat exchange unit 8, the combustion gas and the air taken into the upper unit of the casing 4 by the operation of the blower 7. Heat is exchanged between them to generate dry air. Most of the air taken into the upper unit of the casing 4 of the heat exchanger 2 is the circulating air returned from the circulation port 21, and is taken into the casing 4 of the heat removal device 2 from the intake port 12 of the casing 4. Fresh air (outside air) is added, and the mixed mixed air is heat-exchanged in the heat exchanging unit 8 to generate dry hot air. The dried warm air is introduced into the lower pit 14 of the drying chamber 3 from the lower outlet 13 and blown up into the drying chamber 3 from the lower pit 14, and the fresh leaf tobacco leaves A in the drying chamber 3 are dried. The hot air blown up inside the drying chamber 3 is returned from the circulation port 21 into the upper unit of the casing 4 of the heat exchanger 2.

  The operation of the burner 5 is output controlled by an ON / OFF signal from the control panel 11 in accordance with a drying program for the drying chamber 3 selected in advance. When the dry bulb temperature of the dry bulb thermometer 22 installed near the furnace 6 near the rectifying plate 20 in the drying chamber 3 is an input signal, the burner 5 is turned on by an ON signal when the drying temperature in the drying chamber 3 is lower than the set value. When it is ignited and exceeds the set value, the burner 5 is stopped by an OFF signal. As a result, the drying temperature in the drying chamber 3 is gradually increased from about 38 ° C. to about 68 ° C. or maintained at a constant temperature according to the set value of the drying program of the control panel 11.

  The high-temperature (about 1500 to 2000 ° C.) combustion gas generated in the furnace 6 by the operation of the burner 5 is subjected to heat exchange in the heat exchanging unit 8, and then the combustion chimney 9 in the casing and the chimney outside the casing as combustion exhaust gas. 10 is exhausted to the outside of building B. At this time, the combustion exhaust gas flowing through the in-casing chimney portion 9 is spirally guided along the screw plate 16 in the in-casing chimney portion 9 to stay in the in-casing chimney portion 9 for a long time. . As a result, high-temperature (about 230 to 250 ° C.) combustion exhaust gas heat is efficiently recovered from the in-casing chimney 9 into the upper unit of the casing 4 even after heat exchange. Further, the exhaust heat recovery efficiency is further enhanced by the heat radiation action of the heat radiation fins 17 attached to the outer peripheral surface of the chimney portion 9 in the casing.

  As a result, immediately after the start of the operation of the burner 5, the fresh air (about 25 ° C. to 35 ° C. in summer) is immediately brought into the upper unit of the casing 4 by the exhaust heat collected in the upper unit of the casing 4. The temperature of the hot air introduced into the drying chamber 3 can be increased by heating, and during continuous operation, most of the circulating air from the circulation port 21 and fresh air taken from the intake port 12 are heated simultaneously. Thus, the temperature balance can be made uniform, whereby the operation by the ON / OFF control of the burner 5 can be stabilized. As a result, it is possible to achieve a significant saving in the fuel used for the burner 5 by combining the temperature rise effect and the operation stability effect.

  In the leaf tobacco dryer 1 of the present embodiment, the motor 24 is driven to open and close the intake damper 15 using the wet bulb temperature of the wet bulb thermometer 23 installed near the dry bulb thermometer 22 as an input signal. Control. When the wet bulb temperature of the wet bulb thermometer 23 exceeds the set value of the drying program and the humidity rises more than necessary, the intake damper 15 is opened and fresh air is taken into the casing 4 of the heat exchanger 2, thereby The wind pressure type moisture exhaust damper 26 at the exhaust port 25 on the opposite side of the circulation port 21 of the drying chamber 3 is opened, and the necessary moisture is exhausted.

  Although the application example to the leaf tobacco dryer 1 has been described in the above embodiment, it is needless to say that the present invention can be applied to a heat exchange device for a warm air heater. The hot air heater is configured to include a furnace with a burner in the casing, a heat exchange unit, and a chimney unit, and install a screw plate inside the chimney unit in the casing, and attach a radiating fin to the outer peripheral surface thereof, The heat of the combustion exhaust gas flowing in the chimney portion in the casing is recovered in the casing, fresh air is heated by the recovered exhaust heat, and is sent to the heat exchange portion by a blower. Even in such a warm air heater, exhaust heat recovery efficiency can be enhanced, heat exchange efficiency can be enhanced, and fuel can be saved.

  The inventor of the present invention has a leaf cigarette dryer 1 (Example) having a structure shown in FIG. 1 in which a screw plate 16 is provided inside the chimney portion 9 in the casing and a radiating fin 17 is provided on the outer peripheral surface, and a conventional structure in which they are not provided. A comparative test was conducted on a leaf tobacco dryer (conventional example). Table 1 shows the results of the comparative test. In Table 1, the exhaust gas temperature is the average temperature of the combustion exhaust gas at the front end outlet of the outer casing chimney 10. Similarly, the heat exchange efficiency is obtained according to the calculation formula in the 4-2 heating capacity test of the Agricultural Machinery Research Institute warm air heater test regulations (June 1983) (IAM test code No. 4-1983). It is a number.

表１の試験結果によると、実施例の葉たばこ乾燥機は、従来例の葉たばこ乾燥機に較べると、排気ガス温度で２０℃以上低下しており、当該温度分の排熱がケーシング４内に回収されていること、回収された排熱による熱交換効率の向上が１％を超えていることがそれぞれ確認できた。

According to the test results in Table 1, the leaf tobacco dryer of the example has an exhaust gas temperature lower by 20 ° C. or more than the conventional leaf tobacco dryer, and the exhaust heat corresponding to the temperature is recovered in the casing 4. It was confirmed that the improvement of heat exchange efficiency by the recovered exhaust heat exceeded 1%.

  The heat exchange device and the exhaust heat recovery method thereof according to the present invention can be used as a heat exchange device used in a unit of a dryer or a warm air heater and a waste heat recovery method thereof.

The longitudinal cross-sectional view which shows the leaf tobacco dryer to which the heat exchange apparatus which concerns on this invention is applied, The principal part enlarged view which shows the effect | action of the screw plate in the chimney part in a casing in the heat exchange apparatus of FIG. It is a horizontal sectional view of the chimney part in the casing in the heat exchange device of FIG. It is a perspective view which shows a mode that a screw board is inserted and installed in the chimney part unit in a casing.

DESCRIPTION OF SYMBOLS 1 Leaf tobacco dryer 2 Heat exchange apparatus 3 Drying chamber 4 Casing 5 Burner 6 Furnace 7 Blower 8 Heat exchanger 9 Heating part 9 Casing chimney 9A Casing chimney unit 10 Casing outside chimney 11 Control panel 12 Inlet 13 Outlet 14 Lower part Pit 15 Intake damper 16 Screw plate 17 Radiation fin 18 Container 19 Leaf tobacco hanging tool 20 Current plate 20a Hole 21 Circulation port 22 Dry bulb thermometer 23 Wet bulb thermometer 24 Motor 25 Exhaust port 26 Dehumidification damper A Leaf tobacco fresh leaf B Building

Claims (1)

The lower unit of the casing is provided with a furnace and a heat exchanging unit, the upper unit is provided with a blower , the upper unit is provided with an air intake port and a circulation port through which the circulating air from the drying chamber is provided, and the heat exchange unit In the heat exchange device provided with the chimney that continues from
The chimney has an in-casing chimney extending from the heat exchanging portion extending horizontally in the lower unit directly below the blower to the side facing the circulation port in the vicinity of the blower and extending upward in the upper unit. ,
A screw plate for spirally guiding the exhaust gas after combustion is installed in the chimney portion in the casing extending upward in the upper unit , and a plurality of radiating fins are attached to the outer peripheral surface of the chimney portion in the casing,
Wherein Rukoto fed to the heat exchanging portion of the lower unit by a blower in a state where the upper unit outside air and circulating air taken in is heated by the exhaust gas heat recovered in the upper unit from the casing chimney Heat exchange device.

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