A drying system for controlling the drying temperature of American ginseng

Abstract

The present invention provides a drying system for controlling the drying temperature. The system includes an air heater and a drying device. Air enters the drying device after being heated by the air heater to dry the material. The shell side includes a plurality of shell side inlets and one shell side outlet. The shell side outlet is distributed at the lower end on the left side of the shell side, and the plurality of shell side inlets are distributed at the upper end of the shell side, distributed from the left side to the right side of the shell side. A valve is provided on each shell side inlet pipe. According to the present invention, the flow rate of the heat source at multiple inlets can be controlled, so as to control the heat exchange valves at different positions, so that the air temperature at the outlet can accurately and quickly reach the set value.

Description

Technical Field

[0001] The invention relates to a drying system, in particular to a drying system capable of accurately controlling the drying temperature. Background Art

[0002] At present, in the processing and production of industrial equipment, some processes often require drying and other processing procedures. Hot air drying devices are commonly used to dry them. In traditional hot air blowing devices, due to their unreasonable structural design, the temperature of the hot air does not meet the requirements during the blowing process, resulting in poor drying effect and low work efficiency. It also causes moisture to remain on the surface of the equipment. In addition, these hot air blowing devices cannot be moved very conveniently, which brings a lot of troubles to the staff and wastes the manpower and material resources of the enterprise. The temperature of the existing hot air device is not easy to adjust, and the effect is not ideal, which needs further improvement.

[0003] However, traditional dryers also have the above problems. Under the new energy-saving and emission-reduction situation, their development is greatly restricted. Therefore, in view of these shortcomings, a dryer with a simple structure is developed. By setting multiple input ports, the output temperature of the air can be dynamically adjusted, so that the heat exchange area and heat exchange efficiency can be effectively improved, which is of great significance to industrial production and energy-saving and emission-reduction. Summary of the invention

[0004] In order to overcome the defects and shortcomings in the prior art, the present invention provides a drying system with a novel structure, which can effectively control the output temperature of the air by setting a plurality of air input ports, thereby effectively controlling the drying temperature.

[0005] In order to achieve the above object, the technical solution of the present invention is as follows:

[0006] A drying system for controlling drying temperature, the system comprising an air heater and a drying device, air is heated by the air heater and then enters the drying device to dry the material; the air heater comprises a tube side and a shell side, the tube side comprises a tube side inlet and an outlet, the shell side comprises a shell side inlet and an outlet, the fluids in the tube side and the shell side are heat exchanged, and the shell side is characterized in that the shell side comprises a plurality of shell side inlets and a shell side outlet, the shell side outlets are distributed at the lower end of the left side of the shell side, a plurality of shell side inlets are distributed at the upper end of the shell side, distributed from the left side of the shell side to the right side of the shell side, and a valve is arranged on each shell side inlet pipe.

[0007] As an improvement, the tube pass includes a left header and a right header, and the tube pass inlet and outlet are respectively arranged on the left header and the right header.

[0008] As an improvement, it further includes a controller, which is connected to the valve data. A first temperature sensor is also provided at the shell outlet. The controller controls the opening and closing of each valve and the size of the opening according to the temperature detected by the first temperature sensor.

[0009] As an improvement, it includes a main pipeline, which connects each shell side inlet. The main pipeline is provided with a second temperature sensor. The controller stores the data detected by the first temperature sensor, the data detected by the second temperature sensor, and the data of each valve opening and closing and the opening degree in the first database.

[0010] As an improvement, the controller automatically retrieves the valve opening and closing and opening degree data in the first database according to the set shell outlet temperature and the detected main pipe temperature.

[0011] As an improvement, the main line temperature remains unchanged, and the retrieved data is the data closest to the shell side outlet temperature.

[0012] As an improvement, the set temperature is T, the outlet temperature in the database is T1, and the retrieved data requirement is (T-T1) 2 The data with the smallest absolute value of the difference.

[0013] As an improvement, the total opening of the valve remains unchanged, so that the output flow rate also remains unchanged.

[0014] As an improvement, if the shell side output temperature needs to be increased, the opening of the inlet valve close to the left header is reduced, and the opening of the inlet valve close to the right header is increased, so that the temperature is raised to the predetermined temperature as soon as possible. If the shell side output temperature needs to be reduced, the opening of the inlet valve close to the left header is increased, and the opening of the inlet valve close to the right header is reduced, so that the temperature is reduced to the predetermined temperature as soon as possible.

[0015] Compared with the prior art, the present invention has the following advantages:

[0016] The drying system of the present invention sets multiple inlets on the shell side, and the multiple inlets are arranged along the flow direction of the tube side fluid, so that the heat exchange amount of the shell side fluid participating in different inlets is different, so that the heat exchange amount of the output fluid from the tube side inlet to the tube side outlet gradually increases. By controlling the fluid flow rate of each shell side inlet, the temperature of the output air can be accurately controlled, the control speed of the output air temperature is improved, and the drying temperature in the drying device is accurately controlled. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of the drying system of the present invention.

[0018] Figure 2 It is a structural schematic diagram of the air heater of the present invention.

[0019] Figure 3 It is a structural schematic diagram of the drying equipment of the present invention. DETAILED DESCRIPTION

[0020] The specific implementation modes of the present invention are described in detail below with reference to the accompanying drawings.

[0021] In this article, unless otherwise specified, “ / ” represents division, and “×” and “*” represent multiplication.

[0022] The directional terms such as up, down, left, and right in this article are intended to indicate the relative positional relationship between various components and do not indicate the actual setting positions.

[0023] Figure 1 The drying system of the present invention is shown. Figure 1 As shown, the system includes an air heater 1 and a drying device 2. After being heated by the air heater 1, the air enters the drying device 2 to dry the material.

[0024] Figure 2 The air heater 1 of the present application is disclosed. Figure 2 As shown, an air heater 1 for accurately controlling the output temperature, the air heater 1 comprises a tube side and a shell side, the tube side comprises a tube side inlet 11 and an outlet 12, the shell side comprises a shell side inlet 3 and an outlet 4, and the fluids in the tube side and the shell side perform heat exchange. Figure 2 As shown, the shell side includes a plurality of shell side inlets 3 and a shell side outlet 4, wherein the shell side outlet 4 is distributed at the lower end of the left side of the shell side. Figure 1 Near the position of the left header 5 of the tube side, multiple shell side inlets 3 are distributed at the upper end of the shell side, distributed from the left side of the shell side to the right side of the shell side, that is, arranged along the flow direction of the fluid in the tube side. A valve 7 is set on each shell side inlet pipe. The flow rate of the fluid entering each shell side inlet is controlled by the valve 7. The air enters from the shell side inlet, is heated by the tube side fluid in the heater, and then comes out from the shell side outlet to enter the drying equipment to dry the material 21. The air coming out of the drying equipment is circulated back to the air heater for heating.

[0025] The heat source of the tube side is preferably exhaust gas, and the waste heat of the exhaust gas is used to heat the air.

[0026] The present invention sets multiple inlets in the shell side, and the multiple inlets are arranged along the flow direction of the tube side fluid, so that the heat exchange amount of the shell side fluid participating in different inlets is different, so that the heat exchange amount of the output fluid from the tube side inlet to the tube side outlet gradually increases, and by controlling the fluid flow rate of each shell side inlet, the temperature of the output fluid can be accurately controlled, thereby improving the control speed of the output fluid temperature.

[0027] The output temperature gradually increases along the flow direction of the fluid in the tube.

[0028] Preferably, the tube pass includes a left header 5 and a right header 6, and the tube pass inlet 11 and outlet 12 are respectively arranged on the left header 5 and the right header 6.

[0029] Preferably, a left tube sheet 8 and a right tube sheet 9 are respectively arranged in the left header 5 and the right header 6, and the heat exchange tubes in the tube side connect the left tube sheet and the right tube sheet. The tube side fluid enters from the left header 5, then enters the heat exchange tube, and then flows out from the right header 6 to complete the heat exchange with the shell side fluid.

[0030] Preferably, the material is a medicinal material, and more preferably, it is American ginseng or Cistanche deserticola.

[0031] Preferably, the air heater further comprises a controller, the controller is data-connected with the valve 7, and a first temperature sensor is further provided at the shell outlet for detecting the temperature of the fluid outputted from the shell outlet. The controller is data-connected with the first temperature sensor. The controller controls each valve 7 to perform the following operations according to the temperature detected by the first temperature sensor: opening of the valve 7, closing of the valve 7, and the size of the opening of the valve 7.

[0032] Preferably, the system includes a main pipeline 10, the main pipeline 10 is connected to each shell side inlet 3, and each shell side inlet 3 pipeline is connected in parallel. The main pipeline 10 is provided with a second temperature sensor for detecting the temperature of the fluid entering each inlet. The controller is connected to the second temperature sensor data. The controller stores the temperature data detected by the first temperature sensor, the temperature data detected by the second temperature sensor, and the data of the opening and closing of each valve and the opening degree in the first database. Therefore, a plurality of historical data are stored in the first database.

[0033] As an improvement, the first database may also store shell side outlet flow data.

[0034] Preferably, the controller automatically retrieves the valve opening and closing and opening degree data in the first database according to the set shell outlet temperature and the detected main pipe temperature.

[0035] As an improvement, the main line temperature remains unchanged. The retrieved data is the data closest to the shell outlet temperature. As a preferred method, the shell outlet temperature is set to T, the outlet temperature in the database is T1, and the retrieved data requirement is (T-T1) 2 By setting it in this way, the output temperature can be closest to the set temperature, and then the valve opening is adjusted according to the output temperature detected, so that the output temperature reaches the set temperature as quickly as possible.

[0036] As an improvement, the main line temperature changes. The retrieved data is the temperature closest to the shell outlet and the main line temperature. As a preference, the set outlet temperature is T, the outlet temperature in the database is T1, the detected main line temperature is T2, the main line temperature in the database is T3, and the retrieved data requirement is (T-T1) 2 +(T2-T3) 2 By setting it in this way, the output temperature can be closest to the set temperature, and then the valve opening is adjusted according to the output temperature detected, so that the output temperature reaches the set temperature as quickly as possible.

[0037] As an improvement, if the shell side outlet output temperature needs to be increased, the opening of the inlet valve close to the left header is reduced, and the opening of the inlet valve close to the right header is increased, so that the temperature is raised to the predetermined temperature as soon as possible. If the shell side output temperature needs to be reduced, the opening of the inlet valve close to the left header is increased, and the opening of the inlet valve close to the right header is reduced, so that the temperature is reduced to the predetermined temperature as soon as possible.

[0038] As an improvement, the total opening of all valves 7 remains unchanged, so that the output flow rate also remains unchanged. Therefore, the present application can adjust the temperature to quickly reach the optimal temperature while keeping the flow rate unchanged.

[0039] Preferably, one valve 7 is opened to the maximum opening, and the other valves are closed, and the main line temperature and the output temperature are detected, and the temperature data and valve data are stored in the second database, so as to obtain the output temperature when each valve is opened to the maximum opening.

[0040] Preferably, the controller automatically retrieves data from the second database based on the set shell outlet temperature T and the detected main pipe temperature, and finds the data of two adjacent valves, namely the first valve and the second valve when the opening is maximum, wherein the output temperature data of the first valve is higher than the set temperature but the difference is the smallest among the high data, and the output temperature data of the second valve is higher than the set temperature but the difference is the smallest among the low data, and then the output temperature is adjusted by adjusting the opening of the two valves.

[0041] As an improvement, the main line temperature remains unchanged. The shell outlet temperature is set to T, the data with higher temperature of the adjacent valve in the second database is Tg, and the data with lower temperature is Td. The data required to be retrieved is (T-Tg) 2 +(T-Td) 2 By setting it in this way, the output temperature can be closest to the set temperature, and then the valve opening is adjusted according to the output temperature detected, so that the output temperature reaches the set temperature as quickly as possible.

[0042] As an improvement, the main pipe temperature is variable. The shell outlet temperature is set to T, the main pipe temperature data detected is T2, the adjacent valve temperature data in the database is Tg, the temperature is Td, the main pipe data is T3, and the retrieved data requirement is ((Tg+Td) / 2-T) 2 +(T3-T2) 2 By setting it in this way, the output temperature can be closest to the set temperature, and then the valve opening is adjusted according to the output temperature detected, so that the output temperature reaches the set temperature as quickly as possible.

[0043] As an improvement, when the detected output temperature is higher than the preset temperature, the second valve opening is controlled to increase and the first valve opening is controlled to decrease; when the detected output temperature is lower than the preset temperature, the second valve opening is controlled to decrease and the first valve opening is controlled to increase. The two valves that need to be opened are quickly located in the front, and then the opening and closing of the two adjacent valves are adjusted so that the output temperature quickly reaches the preset temperature.

[0044] As an improvement, when the detected output temperature is higher than the predetermined temperature, and when the second valve opening is at its maximum, the requirement is still not met, the first valve is closed, and another valve adjacent to the second valve whose output temperature is lower than the second valve when opened alone is opened, that is, another inlet valve adjacent to the second valve is opened, and the temperature is adjusted by adjusting the opening of the second valve and the other inlet valve. When the detected output temperature is lower than the predetermined temperature, and when the first valve opening is at its maximum, the requirement is still not met, the second valve is closed, and another valve adjacent to the first valve whose output temperature is higher than the first valve when opened alone is opened is opened. That is, another valve adjacent to the first valve is opened, and the temperature is adjusted by adjusting the opening of the first valve and the other inlet valve.

[0045] Preferably, the total opening of the first valve and the second valve remains unchanged, so that the output flow rate also remains unchanged. Therefore, the present application can adjust the temperature to quickly reach the optimal temperature while keeping the flow rate unchanged.

[0046] The present invention also discloses a control method for accurately controlling the shell outlet temperature of an air heater. The main line temperature remains unchanged, and the method mainly comprises the following steps:

[0047] 1) Open one valve to the maximum opening, close other valves, detect the output temperature, store the temperature data and valve data in the second database, and obtain the shell output temperature when each valve is opened to the maximum opening.

[0048] 2) The user sets the shell side output temperature T, and the controller automatically retrieves the data in the second database according to the set output temperature T. If the temperature T is equal to the shell side output temperature when a certain valve is opened to the maximum degree alone, the valve is controlled to open and other valves are closed.

[0049] 3) If the shell output temperature of a valve when it is opened to the maximum cannot be found in the database, find the data Tg and Td of the two adjacent valves, i.e. the first valve and the second valve when they are opened to the maximum, and require Tg>T>Td. Then adjust the output temperature by adjusting the opening of the two valves.

[0050] 4) When the detected output temperature is higher than the preset temperature, the second valve opening is controlled to increase and the first valve opening is controlled to decrease; when the detected output temperature is lower than the preset temperature, the second valve opening is controlled to decrease and the first valve opening is controlled to increase. The two valves that need to be opened are quickly located in the front, and then the opening and closing of the two adjacent valves are adjusted so that the output temperature quickly reaches the preset temperature.

[0051] As an improvement, when the temperature of the main pipeline is variable, the following steps are included:

[0052] 1) Open one valve to the maximum opening, close other valves, detect the output temperature of the shell outlet and the temperature of the main pipe, store the temperature data and valve data in the second database, and obtain the shell output temperature corresponding to the main pipe temperature when each valve is opened to the maximum opening.

[0053] 2) The user sets the shell output temperature T, and the controller automatically retrieves the data from the second database based on the set output temperature T and the detected main line temperature. At the corresponding main line temperature, if the temperature T is equal to the shell output temperature when a certain valve is opened to the maximum opening, the valve is controlled to open and other valves are closed.

[0054] 3) If the database cannot find the shell output temperature of a valve when it is opened to the maximum at the temperature of the corresponding main pipeline, the data of the adjacent valves with higher temperature in the database is Tg, and the data with lower temperature is Td, that is, the data Tg and Td when the first and second valves are opened to the maximum, and the data of the main pipeline is T3, the data required to be retrieved is ((Tg+Td) / 2-T) 2 +(T3-T2) 2 Then adjust the opening of the adjacent valves according to the output temperature detected, so that the output temperature reaches the set temperature as quickly as possible.

[0055] 4) When the detected output temperature is higher than the preset temperature, the second valve opening is controlled to increase and the first valve opening is controlled to decrease; when the detected output temperature is lower than the preset temperature, the second valve opening is controlled to decrease and the first valve opening is controlled to increase. The two valves that need to be opened are quickly located in the front, and then the opening and closing of the two adjacent valves are adjusted so that the output temperature quickly reaches the preset temperature.

[0056] 5) When the detected output temperature is higher than the predetermined temperature, and the second valve opening is at its maximum, the first valve is closed, and another valve adjacent to the second valve whose output temperature is lower than the second valve when opened alone is opened, that is, another inlet valve adjacent to the second valve is opened. When the detected output temperature is lower than the predetermined temperature, and the first valve opening is at its maximum, the second valve is closed, and another valve adjacent to the first valve whose output temperature is higher than the first valve when opened alone is opened is opened. That is, another valve adjacent to the first valve is opened.

[0057] 6) If the output temperature still does not meet the requirements, continue to repeat step 5) until the output temperature reaches the required level.

[0058] As an improvement, the air heater is a horizontal shell and tube heat exchanger.

[0059] The shell side includes a shell, and a baffle is arranged inside the shell to allow the fluid to flow through the entire tube side to avoid short-circuiting problems.

[0060] As an improvement, the shell side and the tube side are countercurrent flows. Along the flow direction of the fluid in the tube side, the spacing of the baffles increases continuously from the tube side inlet to the middle of the tube side. Then from the middle of the tube side to the tube side outlet, the spacing of the baffles decreases continuously. Because in the countercurrent process, the heat exchange of the shell side and the tube side per unit length along the flow process of the fluid is relatively uniform, so that the overall heat exchange effect is the best. However, it was found in experiments and simulations that the heat exchange in the middle is significantly greater than the heat exchange at the tube side inlet and outlet. Therefore, by changing the spacing of the baffles, the heat exchange area between the tube side fluid and the shell side fluid in the baffles also changes. Therefore, the uneven heat exchange is compensated by the change in area, thereby further improving the heat exchange efficiency.

[0061] As an improvement, along the flow direction of the fluid in the tube, from the tube entrance to the middle of the tube, the distance between the baffles increases continuously. Then, from the middle of the tube to the tube exit, the distance between the baffles decreases continuously. The above changes in the range can make the heat exchange per unit length of the entire fluid movement more uniform, further improving the heat exchange efficiency.

[0062] The baffles are arranged in the vertical direction, including a baffle located at the upper part and a baffle located at the lower part, and the upper baffles and the lower baffles are arranged at intervals; along the flow direction of the fluid in the shell side, the vertical height of the lower baffle extending upward from the bottom shell side inner wall gradually increases, and the vertical length of the upper baffle extending downward from the upper shell side inner wall gradually decreases.

[0063] During the research process, it was found that the heat exchange of the baffles of the traditional heat exchanger is uneven in the cross section in the direction of fluid flow. As the distance from the inlet increases, the density of the heat exchange liquid in the lower part of the shell is large, so the liquid flows downward, which significantly increases the heat exchange liquid in the lower part. Therefore, it is necessary to design a heat exchange structure for improvement. The present invention changes the height of the upper baffle and the lower baffle along the flow direction of the fluid, so that the liquid in the shell gradually moves closer to the center as it flows, so that the heat exchange tubes around the shell and tube center strengthen the heat exchange, which changes the previous heat exchange method, enhances the heat exchange efficiency at different positions, makes the heat exchange uniform as a whole, and further achieves the purpose of enhanced heat transfer.

[0064] As an improvement, along the flow direction of the fluid in the shell side, the vertical height of the lower baffle extending upward from the bottom shell side inner wall gradually increases, and the vertical length of the upper baffle extending downward from the upper shell side inner wall gradually decreases. Through the above-mentioned amplitude changes, the overall heat exchange can be further uniform, and the purpose of enhancing heat transfer can be further achieved.

[0065] Figure 3 The drying device of the present invention is shown. Figure 3 As shown, the drying device includes a box and a conveyor belt 22, the conveyor belt 22 passes through the box, and the air nozzle is located at the lower part of the conveyor belt 22, which transmits hot air upward from bottom to top to dry the material. The power device drives the roller 23, and the roller 23 drives the conveyor belt.

[0066] Preferably, a plurality of nozzles are arranged in the box along the conveying direction of the transmission belt to ensure uniform heating.

[0067] Preferably, the distribution density of the nozzles increases along the conveying direction of the conveyor belt. By changing the distribution density of the nozzles, the amount of hot air along the conveying direction of the conveyor belt can be increased, and the drying effect can be improved, thereby achieving an effect similar to countercurrent heat exchange of a heat exchanger, further improving the drying effect. Preferably, in this case, the output air volume of each nozzle is the same.

[0068] Preferably, along the conveying direction of the conveyor belt, the distribution density of the nozzles increases gradually. Through the above arrangement, the drying effect can be further improved.

[0069] Preferably, the nozzles are evenly distributed along the conveying direction of the conveyor belt, and the air output of the nozzles increases along the conveying direction of the conveyor belt.

[0070] Preferably, along the conveying direction of the conveyor belt, in the heating zone, the air output of the nozzle increases gradually with increasing amplitude.

[0071] By changing the amount of air output from the nozzle, the amount of hot air transmitted along the conveyor belt can be increased, and the drying effect can be improved, thereby achieving an effect similar to countercurrent heat exchange in a heat exchanger, further improving the drying effect.

[0072] Although the present invention has been disclosed as above with preferred embodiments, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, so the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A drying system for controlling the drying temperature of American ginseng, the system comprising an air heater and a drying device, and air enters the drying device after being heated by the air heater to dry the material; the air heater comprises a tube side and a shell side, the tube side comprises a tube side inlet and an outlet, the shell side comprises a shell side inlet and an outlet, and the fluids in the tube side and the shell side perform heat exchange. Characterized in that, The shell side includes multiple shell side inlets and one shell side outlet. The shell side outlet is distributed at the lower end on the left side of the shell side, and the multiple shell side inlets are distributed at the upper end of the shell side, and are distributed from the left side to the right side of the shell side. A valve is provided on each shell side inlet pipe; the material is American ginseng; the system includes a controller, the controller is data-connected to the valves, and a first temperature sensor is further provided at the shell side outlet. The controller controls the opening, closing and opening degree of each valve according to the temperature detected by the first temperature sensor; the system includes a main pipeline, the main pipeline is connected to each shell side inlet, and a second temperature sensor is provided on the main pipeline. The controller stores the data detected by the first temperature sensor, the data detected by the second temperature sensor, the opening and closing and opening degree data of each valve into the first database. The controller automatically retrieves the opening and closing and opening degree data of the valves in the first database according to the set temperature of the shell side outlet and the detected temperature of the main pipeline. When the temperature of the main pipeline remains unchanged, the retrieved data is the data closest to the temperature of the shell side outlet; open one valve to the maximum opening degree, close all other valves, detect the temperature of the main pipeline and the output temperature, and store the temperature data and valve data into the second database, so as to obtain the output temperature when each valve is opened to the maximum opening degree separately; the controller automatically retrieves the data in the second database according to the set temperature T of the shell side outlet and the detected temperature of the main pipeline, and finds the data when the opening degrees of two adjacent valves are the largest. The two valves are the first valve and the second valve. Among them, the output temperature data of the first valve is higher than the set temperature but the difference in the higher data is the smallest, and the output temperature data of the second valve is lower than the set temperature but the difference in the lower data is the smallest. Then, the output temperature is adjusted by adjusting the opening degrees of the two valves; the temperature of the main pipeline remains unchanged, the set temperature of the shell side outlet is T, the data of the adjacent valve with a higher temperature in the second database is Tg, and the temperature of the data with a lower temperature is Td. The retrieved data requirement is (T - Tg) 2 +(T - Td) 2 The smallest data.

2. The drying system according to claim 1, Characterized in that, The tube side comprises a left header and a right header, and the tube side inlet and the outlet are respectively arranged on the left header and the right header.

3. The drying system according to claim 2, Characterized in that, The shell side outlet is close to the left header. If it is necessary to increase the shell side output temperature, the opening degree of the inlet valve close to the left header is reduced, and the opening degree of the inlet valve close to the right header is increased, so that the temperature can be increased to the predetermined temperature as soon as possible; if it is necessary to reduce the shell side output temperature, the opening degree of the inlet valve close to the left header is increased, and the opening degree of the inlet valve close to the right header is reduced, so that the temperature can be reduced to the predetermined temperature as soon as possible.

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