CN210841550U - Humidity control system for redrying tobacco leaves - Google Patents

Abstract

The utility model provides a tobacco leaf humidity control system, which comprises a heat source machine and a controller; the heat source machine comprises a rack and a steam generation module arranged in the rack, wherein the steam generation module comprises a combustion chamber, a low-nitrogen fire-exhaust combustor arranged in the combustion chamber and a heat exchanger positioned above the low-nitrogen fire-exhaust combustor, and the heat exchanger is provided with a cold water inlet and a steam outlet; a water flow sensor is arranged on a water inlet pipeline of the cold water inlet, and a steam flowmeter is arranged on a steam pipeline of the steam outlet; the water flow sensor, the steam flowmeter and the heat source machine are all connected with the controller; the heat exchanger is a finned heat exchanger; or a finned heat exchanger and a tubular light pipe heat exchanger which are arranged in series are formed. The utility model discloses utilize the controller to adjust the income water flow and the combustor air input of cold water entry to the control of steam flow to adjust the dry humidity of steam, with the redrying of guaranteeing the tobacco leaf under suitable condition, the tobacco leaf stable quality can not appear surperficial yellow spot phenomenon.

Description

Humidity control system for redrying tobacco leaves

Technical Field

The utility model relates to a tobacco leaf processing technology field, concretely relates to humidity control system is done in tobacco leaf redrying.

Background

In the preparation processing process of converting tobacco leaves from agricultural products to industrial raw materials, the main operation is drying, and the tobacco leaf redrying is the process of baking the primary prepared raw tobacco again, and the main purpose is to adjust the moisture of the tobacco leaves to about 12 percent and facilitate safe storage. Therefore, the tobacco leaves which are mildewed and do not meet the grade are removed in the redrying processing of the tobacco leaves, impurities and sandy soil are removed, and the tobacco leaves also have the function of killing insects while being heated and dried.

At present, the tobacco redrying process mainly comprises two types:

1. hanging rod redrying (traditional redrying process), hanging the bundled raw tobacco on a tobacco rod, and sending the tobacco rod into a redrying machine for drying. The process is simple, most procedures are manual operation, the labor intensity is high, and the dust content in the air of a working place is high and tends to be eliminated gradually.

2. Threshing and redrying, separating the leaves and the tobacco stems by a threshing machine, and then respectively drying. The popularization of the method is started in the 50 th of the 20 th century, and the method is widely adopted. Because the tobacco leaves are threshed, the tobacco leaves have high anti-crushing capability, and compared with the threshed and threshed in a cigarette factory, the tobacco leaf utilization rate can be improved. The machining process can be mechanized. The tobacco factory directly uses the leaves and the tobacco stems as raw materials, the specification is neat, the sand content is low, the working procedures are reduced, and the production environment is obviously improved. The leaves and stems are dried by a special tobacco roasting machine and a tobacco stem roasting machine (see cigarette machine). However, the steam temperature and humidity of the tobacco leaf roasting machine and the tobacco stem roasting machine are not easy to control, water needs to be sprayed to the redried tobacco leaves to adjust the steam humidity, yellow spots are easily generated on the surfaces of the redried tobacco leaves, the quality of the tobacco leaves is reduced, and the process flow is repeated.

SUMMERY OF THE UTILITY MODEL

Aiming at the defects in the prior art, the utility model provides a tobacco redrying humidity control system, which comprises a heat source machine, can adjust the heat energy supply quantity of the heat source machine in real time according to the quantity of redried tobacco, the moisture content of the tobacco before redrying, the temperature in the redrying process, the moisture regaining process index and the like, is easy to control the steam drying humidity, has simple process flow and does not need to be baked for many times; and the tobacco redrying system adopts the low-nitrogen fire-exhaust burner as the combustion source of the heat source machine, the emission content of combustion nitrogen and oxygen is far lower than the national emission standard, and the energy is saved and the consumption is reduced.

In order to achieve the purpose, the tobacco redrying humidity control system of the utility model comprises a heat source machine and a controller;

the heat source machine comprises a rack and a steam generation module arranged in the rack, the steam generation module comprises a combustion chamber, a low-nitrogen fire-exhaust burner arranged in the combustion chamber and a heat exchanger positioned above the low-nitrogen fire-exhaust burner, and the heat exchanger is provided with a cold water inlet and a steam outlet;

a water flow sensor is arranged on a water inlet pipeline of the cold water inlet, and a steam flowmeter is arranged on a steam pipeline of the steam outlet;

the water flow sensor, the steam flowmeter and the heat source machine are all connected with the controller;

the heat exchanger is a finned heat exchanger;

or the heat exchanger comprises a finned heat exchanger and a tubular light pipe heat exchanger which are arranged in series, wherein the tubular light pipe heat exchanger is positioned above the low-nitrogen fire exhaust burner and below the finned heat exchanger, the cold water inlet is arranged on the finned heat exchanger, and the steam outlet is arranged on the tubular light pipe heat exchanger.

Further, the fin type heat exchanger mentioned above is a double-layer copper heat exchanger.

The utility model discloses a tobacco leaf redrying humidity control system its heat source machine adopts the steam generation module to provide steam, this heat source machine is connected with the controller through the steam flowmeter, the inlet pipe of heat source machine cold water entry is connected with the controller through water flow sensor, the controller adjusts the inlet flow and the combustor air input of cold water entry through monitoring to steam flow, thereby can adjust steam dry humidity in real time, can guarantee that the tobacco leaf that needs redrying does not need to spray water many times in order to adjust steam humidity, thereby can realize the tobacco leaf secondary drying under the steam baking condition of suitable humidity, the steady quality of tobacco leaf has been guaranteed, avoid appearing the yellow spot phenomenon on tobacco leaf surface; and the heat exchanger of the heat source machine can also adopt the combination of a finned heat exchanger and a tubular light pipe heat exchanger, wherein the tubular light pipe heat exchanger is closer to the burner, and the two heat exchangers are arranged in series to form a unidirectional series medium flow path, so that the heat energy of the heat source is utilized more fully, the steam production efficiency is higher, and when the heat source machine is applied to the redrying of tobacco leaves on a large scale, the energy consumption can be obviously reduced, and the economic cost is obviously saved.

Furthermore, a water pump is further arranged on the water inlet pipeline and connected with the controller through a frequency converter.

The controller utilizes the frequency converter to adjust the operating frequency of the water pump through monitoring the steam flow.

Furthermore, the controller adopts a microcomputer control system.

Specifically, the tube array type light tube heat exchanger comprises a heat exchange tube bundle and a plurality of connecting bent tubes, wherein the heat exchange tube bundle is provided with a heat medium inlet and a steam outlet, and the heat medium inlet is communicated with the heat medium outlet of the fin type heat exchanger;

wherein:

the heat exchange tube bundle comprises an upper layer of heat exchange tube rows and a lower layer of heat exchange tube rows, and the upper layer of heat exchange tube rows and the lower layer of heat exchange tube rows are parallel to each other and are arranged in a staggered manner;

the upper heat exchange tube bank comprises a plurality of first heat exchange tubes and second heat exchange tubes which are arranged in parallel, the first heat exchange tubes and the second heat exchange tubes are sequentially and alternately arranged, and the axial centers of the first heat exchange tubes and the axial centers of the second heat exchange tubes are on the same straight line;

the lower heat exchange tube row comprises a plurality of third heat exchange tubes which are arranged in parallel, and the length of each third heat exchange tube is between the first heat exchange tube and the second heat exchange tube; the third heat exchange tubes are arranged in a staggered manner along the axis direction, one end of each third heat exchange tube is flush with the end part of the first heat exchange tube, and the other end of each third heat exchange tube is flush with the end part of the second heat exchange tube;

the first heat exchange tube in the upper heat exchange tube row and the third heat exchange tube which is closest to the first heat exchange tube in the lower heat exchange tube row and has the end part flush with the end part of the first heat exchange tube are communicated through a connecting bent tube; the second heat exchange tube in the upper heat exchange tube row and the third heat exchange tube with the end flush with the end of the second heat exchange tube are communicated through a connecting bent tube to form a one-way snake-shaped alternate heat exchange path.

The tubular light pipe heat exchanger with the structure has the advantages that the fins are not arranged, so that the distance between the heat exchange pipes is shortened, and the defect that when the fin type heat exchanger is close to a fire grate, the heat of the fins cannot be timely transferred to the heat exchange pipes, and the heat exchange pipes are easy to deform is overcome.

Meanwhile, the upper heat exchange tube bank and the lower heat exchange tube bank are parallel to each other and are arranged in a staggered manner, high-temperature flue gas formed after flame combustion of bottom combustion penetrates through a circulation gap formed by the staggered arrangement of the upper heat exchange tube bank and the lower heat exchange tube bank, the flue gas transversely scours the staggered tube bank, the convection heat release coefficient of the flue gas is effectively improved, the heat exchange strength between the flue gas and the heat exchange tube wall is increased, and the convection heat exchange efficiency of the evaporator is improved.

The third heat exchange tube in the lower heat exchange tube row is arranged along the axis direction of the tube, one end of the third heat exchange tube is flush with the end part of the first heat exchange tube, the other end of the third heat exchange tube is flush with the end part of the second heat exchange tube, so that the first heat exchange tube is connected with the third heat exchange tube which is closest to the first heat exchange tube and the end part of the third heat exchange tube is flush with the first heat exchange tube by using the connecting bent tube, when the second heat exchange tube is connected with the third heat exchange tube which is closest to the second heat exchange tube and the end part of the third heat exchange tube is flush with the second heat exchange tube, enough installation and operation space can be ensured, the processing and manufacturing efficiency of the tube type light tube evaporator is improved, the connection.

The combined use of the fin type heat exchanger and the tubular light tube heat exchanger can improve the heat source utilization efficiency of the heat source machine, and the steam output is more component.

Further, the low-nitrogen fire grate combustor comprises a fire grate group and a fire grate gas pipe arranged below the fire grate group, wherein the fire grate group consists of a plurality of fire grate units arranged in parallel; the top end of the fire grate unit is provided with a plurality of fire grate holes, the bottom end of the fire grate unit is provided with double air inlet holes, and an air cavity communicated with the fire grate holes and the double air inlet holes is arranged inside the fire grate unit; a gas nozzle is arranged on the fire exhaust gas pipe corresponding to the double gas inlet holes, the fire exhaust gas pipe is communicated with a gas inlet pipe provided with a gas proportional valve, and the gas proportional valve is electrically connected with the controller; the fire grate unit is concavely provided with a cross-shaped groove for dividing the air cavity into a first air cavity and a second air cavity; an air suction opening is formed in the top of the combustion chamber, and an exhaust fan is arranged at the air suction opening; and a guide plate is also arranged between the lower end of the exhaust fan and the finned heat exchanger.

The utility model discloses a humidity control system is done in tobacco redrying adopts low nitrogen fire to arrange the combustor and provide the heat source for the heat exchanger, and its heat utilization rate is high, and the nitrogen oxygen content that the emission of just burning provided equipment than current heat energy is low.

Furthermore, the low-nitrogen fire row combustor further comprises a water cooling system, the water cooling system comprises a plurality of heat conducting plate groups arranged in parallel and cooling water pipes sequentially penetrating through the plurality of heat conducting plate groups, and the heat conducting plate groups are composed of first heat conducting plates and second heat conducting plates which are respectively arranged on the outer sides of the first air cavity and the second air cavity.

Furthermore, the steam generation modules are more than two groups and are arranged in parallel in the height direction in the rack.

As one arrangement mode, the number of the steam generating modules is four, vertical partition plates are arranged in the rack, the space in the rack is divided into two cavities by the vertical partition plates, and the two cavities are respectively provided with two groups of the steam generating modules which are vertically arranged and connected in parallel.

As another arrangement mode, the steam generation modules are four groups, horizontal partition plates are arranged in the rack, the horizontal partition plates divide the space in the rack into an upper cavity and a lower cavity, and the upper cavity and the lower cavity are internally provided with two groups of steam generation modules which are horizontally arranged and connected in parallel.

Compared with the prior art, the utility model discloses following technological effect has:

a water flow sensor and a steam flow meter which are respectively connected with the controller are arranged to respectively control the amount of cold water entering the heat source machine through a cold water inlet and the amount of steam exiting the steam outlet through the heat source machine; and the water quantity and the steam quantity are adjusted in real time through the feedback of the steam flow meter by the controller, so that the steam humidity adjustment of the redried tobacco leaves is realized, the steam humidity of the redried tobacco leaves is ensured to be proper, water is not required to be sprayed to the surfaces of the tobacco leaves, and the yellow spot defects on the surfaces of the tobacco leaves are avoided.

The heat source machine adopts the combustor with low nitrogen and oxygen emission to provide a heat source for the heat exchanger, the heat utilization rate of the combustor is high, the energy consumption is low, and the tobacco redrying cost can be greatly reduced.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without inventive labor.

FIG. 1 is a block diagram of a humidity control system for redrying tobacco leaves according to the present invention;

FIG. 2 is a schematic view of the overall structure of a heat source machine used in embodiment 1 of the humidity control system for redrying tobacco leaves of the present invention;

FIG. 3 is a schematic view of the steam generating module shown in FIG. 2;

FIG. 4 is a schematic diagram of the internal structure of the steam generating module shown in FIG. 3;

FIG. 5 is a schematic view of the low nitrogen fire row burner of FIG. 4;

FIG. 6 is a schematic structural view of the fire grate unit of FIG. 5;

fig. 7 is a schematic view of an internal structure of a heat source machine steam generation module employed in embodiment 2 of the tobacco redrying humidity control system of the present invention;

FIG. 8 is a schematic structural diagram of the tubular light pipe heat exchanger of FIG. 7;

FIG. 9 is a schematic diagram of a portion of the tubular light pipe heat exchanger shown in FIG. 8;

FIG. 10 is a right side view of the shell and tube light tube evaporator of FIG. 8 with the connecting elbow removed.

Wherein the reference numerals have the following meanings:

1. a frame; 2. a steam generation module; 3. a low nitrogen fire-exhaust burner; 4. a finned heat exchanger; 211. a cold water branch pipe; 212. a cold water inlet; 213. a steam outlet; 214. a steam pipe; 201. a steam main pipe; 202. a backwater main pipe; 7. an exhaust fan; 311. a fire grate unit; 3111. fire holes; 312. a fire exhaust gas pipe; 3121. a gas nozzle; 313. a cooling water pipe; 3141. a first thermally conductive sheet; 3142. a second thermally conductive sheet; 31121. a first air intake hole; 31122. a second air intake hole; 31131. a first air cavity; 31132. a second air cavity; 315. a cross-shaped groove; 35. an ignition gun; 36. a pulse igniter; 61. a main gas inlet pipe; 62. a gas inlet branch pipe; 63. a gas proportional valve; 500. a heat exchange tube bundle; 2121. a thermal medium outlet; 2131. a heat medium inlet; 501. a heat insulation plate; 502. an evaporator support plate; 11. an upper heat exchange tube bank; 511. a first heat exchange tube; 512. a second heat exchange tube; 12. a lower heat exchange tube bank; 521. a third heat exchange tube; 503. and connecting the bent pipe.

Detailed Description

For a better understanding and an implementation, the following detailed description of the embodiments of the present invention is given in conjunction with the accompanying drawings and examples. The following examples are merely illustrative of the present invention and are not intended to limit the scope of the present invention.

It will be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in an orientation or positional relationship indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the device or element so referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the invention.

Example 1

As shown in fig. 1, the humidity control system for redrying tobacco leaves of the present invention comprises a heat source machine and a controller for controlling the heat source machine, wherein the heat source machine has a cold water inlet and a steam outlet, a water flow sensor connected to the controller is disposed on a water inlet pipeline of the cold water inlet, a water pump communicated with the cold water source is further disposed on the water inlet pipeline, and the water pump is connected to the controller through a frequency converter; a steam flow meter connected with the controller is arranged on a steam pipeline communicated with the steam outlet end of the heat source machine, and the steam from the steam outlet is supplied to the tobacco leaf redrying humid room.

As shown in figure 2, the heat source machine structure in the humidity controller for redrying tobacco leaves of the utility model is as shown in figure 1, including frame 1, be provided with vertical baffle in frame 1, separate into two cavities about with the frame inner space, respectively be provided with two sets of steam generation modules 2 in two cavities about should, two sets of steam generation modules 2 are arranged and are parallelly connected the setting about the cavity direction of height.

As illustrated in fig. 3 and 4, the steam generation module 2 includes a combustion chamber, a low-nitrogen fire row burner 3 disposed in the combustion chamber, and a finned heat exchanger 4 disposed above the low-nitrogen fire row burner 3; one end of the finned heat exchanger 4 is provided with a cold water inlet 212, the other end of the finned heat exchanger is provided with a steam outlet 213, the cold water inlet 212 is communicated to a water return main pipe 202 through a cold water branch pipe 211, the water return main pipe 202 is communicated with a water pump (not shown in the figure), and the water return main pipe 202 is provided with a water flow sensor; the steam outlet 213 is connected to the steam main pipe 201 through a steam pipe 214, and the steam main pipe 201 is connected with a steam flow meter electrically connected to the controller, and the steam main pipe 201 is used for providing proper steam for the redried tobacco leaf humid room. The bottom of the low-nitrogen fire exhaust combustor 3 is communicated with a gas inlet branch pipe 62, a gas proportional valve 63 is further arranged on a pipeline of the gas inlet branch pipe 62, one end of the gas proportional valve 63 is connected with a controller, and the other end of the gas proportional valve is communicated with a main gas inlet pipe 61. The supply amount of the gas can be controlled by providing the gas proportional valve 63, thereby adjusting the degree of combustion.

The controller controls the opening of a fuel gas proportional valve 63 of the heat source machine and the cold water flow of a return water main pipe of the heat source machine according to the steam amount fed back by the steam flow meter. The controller is a microcomputer controller.

In addition, referring to fig. 3 and 4, the low-nitrogen fire-row burner 3 is further provided with three burning guns 35, and the combustion chamber is provided with a pulse igniter 36 electrically connected with the burning guns 35. The top of the combustion chamber is also provided with an air suction opening, and the air suction opening is provided with three exhaust fans 7. A guide plate (not shown in the figure) is arranged between the lower end of the exhaust fan 7 and the finned heat exchanger 4, and the exhaust fan 7 uniformly sucks air through the guide plate to avoid the local temperature inside the combustion chamber from being higher and reduce the generation of nitrogen oxides. The four sides of the combustion chamber are wrapped with refractory heat insulation felt (not shown) for heat insulation. The heat insulation plate can prevent the flame from heating the outer frame of the combustion chamber during combustion, so as to generate heat radiation outwards and waste energy; meanwhile, the temperature of the shell of the whole hot water generating equipment is not high, and accidental scalding in the using process is avoided.

Referring to fig. 5 and 6, the low-nitrogen fire grate combustor 3 includes a fire grate group, a fire grate gas pipe 312 under the fire grate group, and a water cooling system for cooling the fire grate group.

The fire grate group consists of a plurality of fire grate units 311 which are arranged in parallel, and the top ends of the fire grate units 311 are provided with a plurality of kidney-shaped fire grate holes 3111; the bottom end of the fire grate unit 311 is also provided with a first air inlet 31121 and a second air inlet 31122, and an air cavity communicating the fire grate holes 3111 and the two air inlets is arranged inside the fire grate unit; a gas nozzle 3121 is arranged at the position of the top end of the fire exhaust gas pipe 312 corresponding to the double gas inlet holes; through setting up two inlet ports, greatly increased the gas proportion to change the ratio between gas and the air, made the burning mix more abundant, thereby reduced nitrogen oxide's emission pollution, reached the effect of low nitrogen. The central position of the lower end of the fire exhaust gas pipe 312 is provided with a gas inlet (not shown in the figure) which is communicated with the gas inlet branch pipe 62.

Referring to fig. 5 and 6, the water cooling system includes a plurality of heat conductive plate groups arranged in parallel, each of which is composed of a first heat conductive plate 3141 and a second heat conductive plate 3142 made of a high heat conductive metal plate and disposed outside the first air cavity 31131 and the second air cavity 31132, and a U-shaped cooling water pipe 313. The cooling water pipe 313 sequentially passes through the plurality of heat conductive sheet groups to be fixed. The cooling water pipe 313 is provided with a cooling water inlet (not numbered) communicated with a cooling water inlet pipe and a cooling water outlet (not numbered) communicated with a cooling water outlet pipe (not numbered). Through set up water cooling system on the fire row group, thereby condenser tube 313 accessible a plurality of heat conduction piece group's that set up side by side heat transfer to arrange the group to the fire and carry out the water-cooling, and then reached rapid cooling's effect, effectively reduced nitrogen oxide's emission.

In addition, the fire damper unit 311 is concavely provided with a cross-shaped groove 315 for dividing the air chamber into a first air chamber 31131 and a second air chamber 31132. Through setting up isolated first air cavity 31131 and second air cavity 31132, refined the distribution of gas, avoided the gas gathering to burn at a certain point, improved the combustion rate, effectively reduced nitrogen oxide's emission.

Specifically, the aforementioned fin heat exchanger 4 is a double-tube copper heat exchanger.

The utility model discloses a humidity control system is dried in tobacco leaf redrying adopts water flow sensor and steam flowmeter to go into the play steam volume of water yield and heat source machine with the cold water of controlling heat source machine respectively to borrow this and adjust the air input of heat source machine, the steam temperature and the humidity that realize being sent to tobacco leaf redrying tide room from this are suitable, avoid the tobacco leaf to become crisp phenomenon because of drying temperature is too high.

TABLE 1 grade index of redried tobacco

Table 2 influence of the tobacco redrying humidity control system of example 1 on redried tobacco indicators

Example 2

The flow diagram of the humidity control system for redrying tobacco leaves disclosed in embodiment 2 is the same as that of embodiment 1, except that the steam generation module of the heat source machine has a different structure, which is specifically different from that of the heat exchanger in the steam generation module, and the same structure as that of embodiment 1 is not repeated herein.

The structure of the steam generation module in this embodiment 2 will be described in detail with reference to fig. 7 to 10.

As illustrated in fig. 7, the steam generation module comprises a combustion chamber, a low-nitrogen fire row burner 3 arranged in the combustion chamber, a tubular light pipe heat exchanger 5 arranged above the low-nitrogen fire row burner 3, and a finned heat exchanger 4 arranged above the tubular light pipe heat exchanger 5; the finned heat exchanger 4 has a cold water inlet 212 and a heat medium outlet 2121, and the tubular light pipe heat exchanger 5 has a steam outlet 213 and a heat medium inlet 2131 communicated with the heat medium outlet 2121 through a pipeline.

The specific structure of the tubular light pipe heat exchanger 5 is shown in fig. 8-10:

the shell and tube light pipe heat exchanger 5 comprises a heat exchange tube bundle 500, a plurality of connecting bent tubes 503, two heat insulation plates 501 and three evaporator support plates 502 which are arranged along the tube axis direction of the heat exchange tube bundle 500 and are positioned between the two heat insulation plates 501; the heat insulation plates 501 are arranged at both ends of the heat exchange tube bundle 500 at intervals; through holes matched with the pipe diameters of the heat exchange pipe bundles 500 are uniformly distributed on the evaporator support plate 502, and the heat exchange pipe bundles 500 penetrate through the through holes; the heat medium inlet 2131 and the steam outlet 213 are respectively arranged at two ends of the heat exchange tube bundle 500;

wherein:

the heat exchange tube bundle 500 comprises an upper heat exchange tube bank 11 and a lower heat exchange tube bank 12, wherein the upper heat exchange tube bank 11 and the lower heat exchange tube bank 12 are parallel to each other and are arranged in a staggered manner;

the upper heat exchange tube bank 11 comprises a plurality of first heat exchange tubes 511 and second heat exchange tubes 512 which are arranged in parallel, the first heat exchange tubes 511 and the second heat exchange tubes 512 are sequentially and alternately arranged, and the axial centers of the first heat exchange tubes 511 and the axial centers of the second heat exchange tubes 512 are on the same straight line;

the lower heat exchange tube bank 12 comprises a plurality of third heat exchange tubes 521 which are arranged in parallel, and the length of each third heat exchange tube 521 is between the first heat exchange tube 511 and the second heat exchange tube 512; the third heat exchange tubes 521 are staggered along the axial direction, one end of each third heat exchange tube is flush with the end part of the first heat exchange tube 511, and the other end of each third heat exchange tube is flush with the end part of the second heat exchange tube 512;

the first heat exchange tube 511 in the upper heat exchange tube bank 11 is communicated with the third heat exchange tube 521 closest to the first heat exchange tube 511 in the lower heat exchange tube bank 12, and the end part of the third heat exchange tube 521 is flush with the end part of the first heat exchange tube 511 through a connecting bent tube 503; the second heat exchange tube 512 in the upper heat exchange tube bank 11 is communicated with the third heat exchange tube 521 closest to the second heat exchange tube 512 in the lower heat exchange tube bank 12, and the end part of the third heat exchange tube 521 is flush with the end part of the second heat exchange tube 512 through a connecting bent tube 503, so as to form a unidirectional snake-shaped alternate heat exchange path.

In practical application, the number of the evaporator supporting plates is reasonably arranged according to the length of the heat exchange tube and is uniformly arranged along the heat exchange tube.

Table 3 influence of the tobacco redrying humidity control system of example 2 on redried tobacco indicators

The technical means disclosed by the scheme of the present invention is not limited to the technical means disclosed by the above embodiments, but also includes the technical scheme formed by the arbitrary combination of the above technical features. It should be noted that, for those skilled in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications are also considered as the protection scope of the present invention.

Claims (9)

1. The tobacco redrying humidity control system is characterized by comprising a heat source machine and a controller;

the heat source machine comprises a rack (1) and a steam generation module (2) arranged in the rack, wherein the steam generation module (2) comprises a combustion chamber, a low-nitrogen fire-exhaust combustor (3) arranged in the combustion chamber and a heat exchanger positioned above the low-nitrogen fire-exhaust combustor (3), and the heat exchanger is provided with a cold water inlet (212) and a steam outlet (213);

a water flow sensor is arranged on a water inlet pipeline of the cold water inlet (212), and a steam flowmeter is arranged on a steam pipeline of the steam outlet;

the water flow sensor, the steam flowmeter and the heat source machine are all connected with the controller;

the heat exchanger is a finned heat exchanger (4);

or the heat exchanger comprises a finned heat exchanger (4) and a tubular light pipe heat exchanger (5) which are arranged in series, wherein the tubular light pipe heat exchanger (5) is positioned above the low-nitrogen fire exhaust burner (3) and below the finned heat exchanger (4), a cold water inlet (212) is arranged on the finned heat exchanger (4), and a steam outlet (213) is arranged on the tubular light pipe heat exchanger (5).

2. The tobacco redrying humidity control system according to claim 1, wherein a water pump is further arranged on the water inlet pipeline, and the water pump is connected with the controller through a frequency converter.

3. The tobacco redrying humidity control system of claim 1 or 2, wherein the controller is a microcomputer controller.

4. The tobacco redrying humidity control system according to claim 3, characterized in that the tube nest type light pipe heat exchanger (5) comprises a heat exchange tube bundle (500) and a plurality of connecting bent tubes (503), the heat exchange tube bundle (500) is provided with a heat medium inlet (2131) and a steam outlet (213), and the heat medium inlet (2131) is communicated with the heat medium outlet of the fin type heat exchanger (4);

wherein:

the heat exchange tube bundle (500) comprises an upper layer of heat exchange tube rows (11) and a lower layer of heat exchange tube rows (12), wherein the upper layer of heat exchange tube rows (11) and the lower layer of heat exchange tube rows (12) are parallel to each other and are arranged in a staggered manner;

the upper-layer heat exchange tube bank (11) comprises a plurality of first heat exchange tubes (511) and second heat exchange tubes (512) which are arranged in parallel, the first heat exchange tubes (511) and the second heat exchange tubes (512) are sequentially and alternately arranged, and the axial centers of the first heat exchange tubes (511) and the second heat exchange tubes (512) are on the same straight line;

the lower heat exchange tube row (12) comprises a plurality of third heat exchange tubes (521) which are arranged in parallel, and the length of each third heat exchange tube (521) is between the first heat exchange tube (511) and the second heat exchange tube (512); the third heat exchange tubes (521) are staggered along the axial direction, one end of each third heat exchange tube is flush with the end part of the first heat exchange tube (511), and the other end of each third heat exchange tube is flush with the end part of the second heat exchange tube (512);

the first heat exchange tube (511) in the upper heat exchange tube bank (11) is communicated with the third heat exchange tube (521) which is closest to the first heat exchange tube (511) in the lower heat exchange tube bank (12) and the end part of which is flush with the end part of the first heat exchange tube (511) through a connecting bent tube (503); and a second heat exchange tube (512) in the upper heat exchange tube bank (11) is communicated with a third heat exchange tube (521) which is closest to the second heat exchange tube (512) in the lower heat exchange tube bank (12) and has the end flush with the end of the second heat exchange tube (512) through a connecting bent tube (503) so as to form a one-way snake-shaped alternative heat exchange path.

5. The tobacco redrying humidity control system according to claim 4, characterized in that the low nitrogen fire grate burner (3) comprises a fire grate group and a fire grate gas pipe (312) arranged below the fire grate group, the fire grate group is composed of a plurality of fire grate units (311) arranged in parallel; the top end of the fire grate unit (311) is provided with a plurality of fire grate holes, the bottom end of the fire grate unit is provided with double air inlet holes, and an air cavity communicated with the fire grate holes and the double air inlet holes is arranged inside the fire grate unit; a gas nozzle is arranged on the fire exhaust gas pipe (312) corresponding to the position of the double gas inlets, the fire exhaust gas pipe (312) is communicated with a gas inlet branch pipe (62) provided with a gas proportional valve (63), and the gas proportional valve (63) is electrically connected with the controller; a cross-shaped groove (315) for dividing the air cavity into a first air cavity (31131) and a second air cavity (31132) is concavely arranged on the fire grate unit (311); an air suction opening is formed in the top of the combustion chamber, and an exhaust fan (7) is arranged at the air suction opening; and a guide plate is also arranged between the lower end of the exhaust fan (7) and the finned heat exchanger (4).

6. The tobacco redrying humidity control system according to claim 5, characterized in that, the low-nitrogen fire grate combustor (3) further comprises a water cooling system, the water cooling system comprises a plurality of heat conducting plate groups arranged in parallel and cooling water pipes (313) sequentially penetrating through the plurality of heat conducting plate groups, and the heat conducting plate groups are composed of a first heat conducting plate (3141) and a second heat conducting plate (3142) which are respectively arranged at the outer sides of the first air cavity (31131) and the second air cavity (31132).

7. The tobacco redrying humidity control system according to claim 5 or 6, characterized in that the steam generation modules (2) are arranged in parallel in the height direction of the frame (1) and are more than two groups.

8. The tobacco redrying humidity control system according to claim 7, characterized in that the steam generation modules (2) are four groups, vertical partition plates are arranged in the frame (1) and divide the space in the frame (1) into two cavities, and the two cavities are respectively provided with two groups of the steam generation modules (2) which are arranged up and down and connected in parallel.

9. The tobacco redrying humidity control system according to claim 7, characterized in that, the steam generation modules (2) are four groups, horizontal clapboards are arranged in the frame (1), the horizontal clapboards divide the space in the frame (1) into an upper cavity and a lower cavity, and two groups of the steam generation modules (2) which are horizontally arranged and connected in parallel are arranged in the upper cavity and the lower cavity.

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