JP5670166B2 - Hot air heater for horticulture - Google Patents

Description

  The present invention relates to a hot air heater that heats the inside of a facility horticulture house with hot air.

  Usually, the furnace body (heat exchanging part) of this type of hot air heater is generally a one-pass type (FIG. 7) from the viewpoint of manufacturing cost (see, for example, Patent Documents 1 and 2). . In the house warming by the hot air heater, the air in the house is taken into the casing 1 by the blower 2, and the combustion heat (combustion gas) by the air in the house and the burner 3 is heated by the furnace body (the furnace 4 and the smoke tube group 5). Heating is performed by exchanging the warm air from the discharge port 6 through a duct. Combustion gas is exhausted from the chimney 7. Conventionally, a highly efficient heater with a small amount of fuel has been demanded, but further efficiency has been demanded due to the rising price of heavy oil and environmental policies.

JP-A-5-133610 JP 2006-317043 A

  Since the thermal efficiency of the heater is calculated by the offset ratio between the lower heating value per unit heat quantity and the exhaust gas loss heat quantity, the lower the exhaust gas loss heat quantity (the exhaust gas temperature in the chimney), the higher the thermal efficiency. However, the durability of hot air heaters for horticultural horticulture is usually designed with a goal of 10 years or more, so considering metal fatigue, the thermal efficiency is limited to 90%, and it is difficult to raise it further. It was.

  In addition, heavy oil A (JIS Type 1 No. 1) is the mainstream fuel used for facility horticulture heating due to price, calorific value, etc., but heavy oil A contains less than 1% sulfur and exhaust gas temperature. If the temperature is too low, sulfuric acid is generated by the sulfur reaction contained in the fuel (low temperature corrosion), which corrodes the metal and lowers the durability of the heater.

  The present invention has been made in view of the above problems, and provides a warm air heater for facility horticulture that has improved heat transfer performance by improving the furnace body and thereby improved thermal efficiency, and has improved exhaust heat recovery performance. An object of the present invention is to provide a warm air heater for facility horticulture with higher thermal efficiency, and to provide a warm air heater for facility horticulture having excellent low-temperature corrosion performance.

In order to solve the above problems, a warm air heater for facility horticulture according to the present invention,
A casing, which is disposed sideways in the casing, has a length exceeding 1/2 of the total length of the casing, has the nozzle portion of the burner facing one end, and has a concave shape centered on the center line of the nozzle portion at the other end of consists curved surface, a cylindrical furnace which reversed portions are formed to reverse along the combustion gas in the furnace wall, the first to derive an inverted combustion gas from near one end of the furnace to the furnace outside the casing and smoke chamber, a first tobacco pipe group for guiding the combustion gases toward the other end of the furnace from the first smoke box, mounted on the upper surface of the casing, to perform heat exchange between the combustion gas by the downward air blowing A blower, a second smoke chamber for collecting combustion gas flowing through the first smoke tube group in the casing, a second smoke tube group for guiding the combustion gas downward from the second smoke chamber near the other end of the furnace in the casing, In the casing the second stack A third smoke chamber to set the combustion gas, and a chimney to exhaust from the third smoke chamber combustion gas to the outside of the casing, the exhaust attraction to attract the exhaust of the combustion gas in the middle of or between chimney third smoke chamber and the chimney The burner nozzle portion is provided with a diffuser in front of the nozzle body, and a trumpet-shaped funnel portion is formed at the tip of the outer cylinder surrounding the nozzle body .

According to the hot air heater for facility horticulture according to the present invention, the fuel combusted by the burner in the combustion chamber of the furnace emits a bright flame when combusting and transmits the combustion heat to the furnace wall by radiation. Subsequently, the combustion gas is reversed along the inner wall surface of the furnace at the reversing portion located on the opposite side of the nozzle portion of the burner, flows so as to lick the inner wall surface of the furnace, and is guided from the furnace into the first smoke chamber. At that time, it flows while further transferring combustion gas heat to the furnace wall. Compared with the conventional one-pass type and two-pass type furnaces, the return combustion gas can make the contact time with the inner wall of the furnace longer, and the amount of heat transfer to the furnace wall increases. That is, by adopting a return combustion method in which the combustion gas returns in the furnace (reverse return), the heat transfer performance can be enhanced as compared with the conventional case.
In addition, by improving the heat transfer performance, the size of the furnace placed sideways in the casing is reduced, and a device for heat exchange and exhaust heat recovery from the first smoke chamber to the third smoke chamber is provided in the casing. A hot air heater with a high heat exchange rate can be realized in a compact size.

  A second feature of the hot air heater for facility horticulture according to the present invention is that the reversing portion has an inner wall surface shape that smoothly curves from an end surface at the other end of the furnace to a side peripheral surface.

  The hot air heater for horticultural horticulture according to the present invention is characterized in that a screw plate that guides the combustion gas in a spiral shape is arranged in the smoke pipe of the smoke pipe group. The arrangement of the screw plate promotes the diffusion action of the combustion gas flowing in the smoke pipe, increases the contact time with the pipe wall of the smoke pipe, and increases the amount of heat transfer to the pipe wall.

  The hot air heater for facility horticulture according to the present invention is characterized in that a screw plate for guiding the combustion gas in a spiral shape is arranged in the smoke pipe of the second smoke pipe group. The arrangement of the screw plate promotes the diffusion action of the combustion gas flowing in the smoke pipe, increases the contact time with the pipe wall of the smoke pipe, and increases the amount of heat transfer to the pipe wall. This increases the exhaust heat recovery rate.

  The facility horticultural hot air heater according to the present invention has as a seventh feature that each smoke tube of the second smoke tube group is made of a sulfuric acid resistant material. Durability against low-temperature corrosion accompanying a decrease in combustion gas temperature after exhaust heat recovery is improved.

  The facility horticultural hot air heater according to the present invention has an eighth feature that a dispersion means for dispersing combustion gas toward the chimney entrance is dispersed in the third smoke chamber.

  The hot air heater for horticultural horticulture according to the present invention includes an air nozzle and an annular nozzle portion that is provided near the entrance of the chimney and converts an air flow generated by the air fan into a jet flow directed into the chimney. The tenth feature is to have

As described above, according to the facility horticulture hot air heater according to the present invention, the heat transfer performance of the furnace is improved by reversing the combustion gas along the inner wall surface of the furnace while realizing stable burner combustion. As a result, the heat exchange efficiency can be greatly improved. Further, by providing the exhaust heat recovery means, it is possible to further improve the heat exchange efficiency.

  Further, according to the hot air heater for facility horticulture according to the present invention, the furnace can be made compact, and the exhaust heat recovery means can be stored vertically in the vacant space in the casing, which is compact and has excellent heat exchange efficiency. There is an excellent effect that a wind heater can be realized.

Sectional drawing which shows the warm air heater for facilities gardening which concerns on this invention, AA line arrow cross section of the hot air heater of FIG. An enlarged sectional view showing the nozzle part of the burner, (A) is a plan view showing the arrangement of the second smoke tube group, (B) is a cross-sectional view showing the vicinity of the third smoke chamber from the second smoke tube group, (C) is the third smoke chamber shown in (B) from the front. Cross section seen, A side view showing the exhaust attraction means, (A) is a side view showing the vicinity of the discharge part, (B) is a cross-sectional view of the discharge part, It is sectional drawing which shows the conventional hot air heater for facility gardening of the one pass type.

  An embodiment for carrying out the present invention will be described with reference to FIGS. In FIG. 1, 100 is a warm air heater for facility horticulture.

  As shown in FIG. 1, the facility horticulture hot air heater 100 has a cylindrical furnace 110 disposed horizontally in a casing 101, and a nozzle portion 121 of a burner 120 faces a combustion chamber 111 at one end of the furnace 110. Arranged in a shape. At the other end of the furnace 110, an inversion portion 112 is formed opposite the nozzle portion 121 to invert the combustion gas G along the inner wall surface of the combustion chamber 111.

  More specifically, the inversion portion 112 has an inner wall surface of the end surface 110a on the other end side of the furnace 110 as a concave curved surface centered on the center line of the nozzle portion 121, and further from the end surface 110a to the furnace 110. It has an inner wall surface shape that is smoothly curved and connected to the inner peripheral surface of the trunk portion 110b.

  In the upper part near one end of the furnace 110, an opening 110 c that leads the inverted combustion gas G upward in the casing 101 to the outside of the furnace 110 and a first gas that covers the opening 110 c and collects the combustion gas G once. A smoke chamber 130 is provided. Connected to the first smoke chamber 130 is a first smoke tube group 140 that guides the combustion gas G toward the other end of the furnace 110 above the furnace 110. As shown in FIG. 2, each of the smoke tubes 141 is arranged in a large number on the left and right (a total of 11 in the illustrated example) and in two rows or a zigzag on the top and bottom. A screw plate 142 that guides the combustion gas G passing through the inside in a spiral manner along the inner wall surface of the pipe is inserted and disposed in each smoke pipe 141.

  As shown in FIG. 3, the nozzle portion 121 of the burner 120 is provided with a diffuser 122 in front of the nozzle body 121a, and a trumpet-shaped funnel portion 123 is formed at the tip of an outer cylinder 121b surrounding the nozzle body 121a. The funnel portion 123 is formed with an enlarged diameter portion 123a that continues from the outer cylinder 121b, an annular portion 123b that continues from the enlarged diameter portion 123a, and a bent portion 123c that bends inward from the end of the annular portion 123b.

  On the upper surface of the casing 101, there are provided two air inlets 101a, and two air blowers 150 and 150 that exchange heat with the combustion gas G by blowing are attached to each of the air inlets 101a. It has been. These blowers 150 take in the air in the house into the casing 101 by the rotation of the blower fan 151, and the combustion heat G in the combustion chamber 111 of the furnace 110 and the combustion gas G generated along with the combustion from the furnace 110 to the first smoke pipe. While being exhausted from the group 140, the second smoke pipe group 170 described later, to the chimney 190, hot air is generated by heat exchange.

  A second smoke chamber 160 that collects the combustion gas G flowing in each smoke tube 141 is connected to the end of the first smoke tube group 140. Connected to the lower surface of the second smoke chamber 160 is a second smoke tube group 170 extending in the longitudinal direction for guiding the combustion gas G downward in the casing 101 and recovering the residual heat of the combustion gas G. The second smoke tube group 170 is for recovering the residual heat of the combustion gas G, and is arranged in the vertical (vertical) direction in the gap space S between the end surface 120a on one end side of the furnace 120 and the end surface of the casing 101. .

  As shown in FIG. 4 (A), each of the smoke tubes 171 is arranged in a large number on the left and right (total 11 in the illustrated example), and arranged in two rows or zigzag in the front and rear. Each smoke pipe 171 is inserted with a screw plate 172 that guides the combustion gas G flowing downward in the spiral in the same manner as the smoke pipe 141. In order to prevent low temperature corrosion due to the condensation of the combustion gas G, each smoke pipe 171 is made of sulfuric acid resistant steel (trade name: “S-TEN steel” manufactured by Nippon Steel Corp.). A drain pipe for draining condensed water is attached to the lower part of each smoke pipe 171 so that the drain can be drained out of the casing 101.

  A third smoke chamber 180 for collecting the combustion gas G after exhaust heat recovery flowing in each smoke tube 171 is connected to the end of the second smoke tube group 170 in the casing 101. In the third smoke chamber 180, as shown in FIGS. 4B and 4C, the combustion gas G toward the inlet of the chimney 190 is dispersed, that is, the combustion gas G on the side close to the inlet of the chimney 190 is discharged. A dispersion plate 181 is provided to make a detour on the far side of the entrance of 190.

  Unlike the upward direction, the combustion gas G that flows downward through the second smoke tube group 170 tends to increase the gas resistance, and a flow that concentrates on a portion with a low resistance (portion close to the inlet of the chimney 190) occurs. Due to the presence of the dispersion plate 181, the combustion gas G far from the inlet of the chimney 190 becomes an average flow, and a balanced heat exchange, that is, more efficient exhaust heat recovery is possible.

  A chimney 190 extending outside the casing 101 is connected to the side surface of the third smoke chamber 180. Between the outlet of the third smoke chamber 180 and the inlet of the chimney 190, an exhaust gas inducer (exhaust gas booster) 200 for attracting the combustion gas G to the chimney 190 side is provided. In the exhaust gas attractor 200, an annular ejection nozzle portion 203 is formed between the first cylinder 201 connected to the outlet of the third smoke chamber 180 and the second cylinder 202 connected to the inlet of the chimney 190. ing.

As shown in FIG. 5, the ejection nozzle portion 203 has a reduced diameter portion 201 a in which the distal end portion of the first cylindrical body 201 is gradually reduced in diameter, and a reduced diameter portion in which the rear end portion of the second cylindrical body 202 is gradually reduced in diameter. 202a, the tip of the reduced diameter portion 201a on the first cylinder 201 side is formed in an annular horizontal portion 201b that extends horizontally, and the tip of the reduced diameter portion 202a of the second cylinder 202 is the first cylinder 201. It is formed on the outer side of the horizontal portion 201b on the side, and on the enlarged diameter portion 202b that bends upward along the outer surface of the reduced diameter portion 201a of the first cylindrical body 201. An annular gap d ₁ is formed between the rear end portion of the second cylinder 202 and the front end portion of the first cylinder 201.

  An annular ventilation chamber 204 is provided around the first cylinder 201 and the second cylinder 202 so as to surround the annular ejection nozzle portion 203. Casings 205A and 205B that open air inlets 205a are attached to the side of the annular ventilation chamber 204, and a two-stage suction fan (impeller) that is driven to rotate by a motor 206 is accommodated in each of the casings 205A and 205B. ing.

  When the suction fan is driven to rotate by the motor 206, the exhaust gas attractor 200 attracts the air in the house from the casings 205A and 205B into the annular ventilation chamber 204 and enters the inside of the chimney 190 from the annular ejection nozzle portion 203. As a result, a negative pressure is generated inside the first cylinder 201 and the second cylinder 202, and the combustion gas G in the third smoke chamber 180 is attracted toward the chimney 190. ing.

  Depending on the arrangement of the chimney 190, the local resistance of the chimney 190 may cause the combustion gas G to be pulled poorly (exhaust resistance). The exhaust gas attractor 200 eliminates the loss due to the local resistance of the chimney 190 and realizes stable burner combustion. Further, the combustion gas G is diluted by blowing the outside air from the ejection nozzle portion 203, the temperature of the combustion gas is lowered, and it is possible to eliminate the chimney such that the construction of installing the exhaust pipe at a high place becomes unnecessary.

  On the lower surface near the other end of the casing 101, there is provided a discharge unit 210 having a discharge chamber 211 for discharging hot air generated in the casing 101, and a discharge port for discharging hot air on each side surface of the discharge unit 210. 210a is formed. Ducts (not shown) are connected to the respective outlets 210a, and warm air is distributed throughout the entire area of the facility horticulture house through the ducts.

As shown in FIGS. 6A and 6B, the discharge chamber 211 is provided with a hot air diffusion plate 212 for diffusing the warm air flowing downward from the inside of the casing 101 through the opening on the lower surface in the discharge chamber 211. Has been. The hot air diffusion plate 212 is held in a horizontal posture just below the opening, and an opening 212 a is provided at the center of the hot air diffusion plate 212, and the periphery of the hot air diffusion plate 212 and the inner peripheral surface of the discharge chamber 211. clearance d ₂ is provided between the.

Since the warm air discharged by the conventional warm air heater is distributed with almost no mixing part, there is usually a temperature variation of about 5 to 10 ° C. Therefore, by disposing the hot air diffuser 212 into the discharge chamber 210, hot air flowing into the discharge chamber 211 to downward, flow through the hot air diffuser 212 central opening 212a and the surrounding gap d ₂ Thus, diffusion is promoted and mixing in the discharge chamber 211 is promoted. As a result, the air is discharged from each discharge port 210a as warm air having a uniform temperature (temperature variation within 3 ° C.).

  In FIG. 1, reference numeral 220 denotes a control unit that controls each operation of the burner 120, the two blowers 150, and the exhaust gas attractor 200 based on a temperature sensor or the like installed in the house.

  Next, an operation of the facility horticulture hot air heater 100 having the above-described configuration will be described. First, when two blowers 150 are operated and the fuel sprayed into the combustion chamber 111 from the nozzle part 121 of the burner 120 is ignited and burned by an ignition device, the combustion heat is transmitted to the furnace inner wall by radiation. The combustion gas G at a high temperature (about 1700 ° C. to 1900 ° C.) reaches the furnace inner wall surface of the front end face 110a, and reverses so as to lick the furnace inner wall surface and the furnace inner peripheral surface of the body 110b. While facing the opening 101b on the opposite side, the high-temperature combustion gas G transfers heat to the furnace wall and enters upward into the first smoke chamber 130 from the opening 101b.

  Further, as shown in FIG. 3, the fuel sprayed from the nozzle body 121a of the nozzle part 121 through the front diffuser 122 blows out a flame forward by ignition. At this time, in the funnel part 123, at the center and the periphery thereof. The vortex flow U is generated, and the generated vortex flow U exerts an effect of rectifying the flame. As a result, the high-temperature combustion gas G travels straight to the furnace inner wall straight ahead and reverses to efficiently transfer heat to the furnace wall.

  The high-temperature combustion gas G that has entered the first smoke chamber 130 upward enters the horizontal first smoke tube group 140 and passes through each smoke tube 141, while the high-temperature combustion gas G transfers heat to the tube wall. However, it goes to the second smoke chamber 160. Here, heat exchange is performed between the air in the house taken into the casing 101 from the upper two blowers 150 and 150 and the heat transferred to the tube wall of the smoke tube 141 and the furnace wall of the furnace 110. The warm air generated by the heat exchange passes through the casing 101 and goes into the lower discharge chamber 211.

  Due to the heat transfer effect of the combustion gas G reversed by the reversing unit 112 in the furnace 110 and the diffusion and heat transfer effect of the combustion gas G by the screw plate 142 disposed in the first smoke tube unit 140, the first smoke tube unit 140. The effect of reducing the combustion gas G temperature at the outlet of the gas by about 60 ° C. (thermal efficiency is improved by 3 to 4%) occurs.

  The combustion gas G that has entered the second smoke chamber 160 enters the second smoke tube group 170 downward and flows downward in each smoke tube 171, while transferring the residual heat of the combustion gas G to the tube wall while Head to the smoke chamber 180. Here, the above-described warm air toward the lower discharge chamber 211, that is, warm air generated by heat exchange, is again heat-exchanged with the heat collected by the second smoke tube group 170, and further heated. The heated warm air goes to the discharge chamber 211 below.

  Due to the exhaust heat recovery effect of the second smoke tube group 170 itself and the diffusion and heat transfer effect of the combustion gas G by the screw plate 172 disposed in each smoke tube 171, the combustion gas G temperature at the outlet of the second smoke tube unit 170 is further increased. An effect of reducing the temperature by about 100 ° C. (thermal efficiency improved by 5%) is produced.

  The hot air that has entered the discharge chamber 211 is distributed into the house through the duct from the discharge port 210a. Conventionally, the discharge temperature difference is normally about 5 to 10 ° C. Due to the presence of 212, the mixing performance in the discharge chamber 211 was improved, and the discharge temperature difference could be reduced within 3 ° C.

  The combustion gas G flowing downward through the second smoke tube group 170 enters the third smoke chamber 180 at an exhaust temperature of about 150 ° C. by exhaust heat recovery, and becomes a substantially uniform flow due to the dispersion effect by the dispersion plate 181. Head to the chimney 190 entrance. Due to the exhaust gas attracting effect of the exhaust gas attractor 200 provided at the inlet of the chimney 190, the exhaust gas recovered combustion gas G is quickly exhausted without staying in the chimney 190. As a result, stable burner combustion is achieved, and a series of flows of heat transfer, heat exchange, exhaust heat recovery, and exhaust of the combustion gas are performed smoothly.

  Thus, while the thermal efficiency of the conventional hot air heater was limited to 90% at most, the hot air heater 100 for horticulture in this embodiment succeeded in increasing the thermal efficiency to 95%.

  The warm air heater for facility horticulture according to the present invention can be widely used as a warm air heater for heating the inside of a facility horticulture house with warm air.

DESCRIPTION OF SYMBOLS 100 Facility gardening warm air heater 101,205A, 205B Casing 101a, 205a Inlet 101b, 110c, 212a Opening part 110 Furnace 110a End face 110b Body part 111 Combustion chamber 112 Reversing part 120 Burner 121 Nozzle part 121a Nozzle main body 121b Outer cylinder 122 diffuser 123 funnel part 123a enlarged diameter part 123b annular part 123c bent part 130 first smoke chamber 140 first smoke tube group 141,171 smoke tube 142,172 screw plate 150 blower 151,207 blower fan 160 second smoke chamber 170 second smoke tube Group 180 Third smoke chamber 181 Dispersing plate 190 Chimney 200 Exhaust gas attractor (exhaust gas attracting means)
201 1st cylinder 201a, 202a Diameter reduction part 201b Horizontal part 202 2nd cylinder 202b Diameter expansion part 203 Jet nozzle part 204 Ventilation chamber 206 Motor 210 Discharge part 211 Discharge room 210a Discharge port 212 Hot air diffusion plate 220 Control part d ₁ , d ₂ gap G Combustion gas

Claims (1)

A casing, which is disposed sideways in the casing, has a length exceeding 1/2 of the total length of the casing, has the nozzle portion of the burner facing one end, and has a concave shape centered on the center line of the nozzle portion at the other end of consists curved surface, a cylindrical furnace which reversed portions are formed to reverse along the combustion gas in the furnace wall, the first to derive an inverted combustion gas from near one end of the furnace to the furnace outside the casing and smoke chamber, a first tobacco pipe group for guiding the combustion gases toward the other end of the furnace from the first smoke box, mounted on the upper surface of the casing, to perform heat exchange between the combustion gas by the downward air blowing A blower, a second smoke chamber for collecting combustion gas flowing through the first smoke tube group in the casing, a second smoke tube group for guiding the combustion gas downward from the second smoke chamber near the other end of the furnace in the casing, In the casing the second stack A third smoke chamber to set the combustion gas, and a chimney to exhaust from the third smoke chamber combustion gas to the outside of the casing, the exhaust attraction to attract the exhaust of the combustion gas in the middle of or between chimney third smoke chamber and the chimney A hot air heater for horticultural horticulture, characterized in that a burner nozzle portion is provided with a diffuser in front of the nozzle body and a trumpet-shaped funnel portion is formed at the tip of an outer cylinder surrounding the nozzle body .

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