High-efficiency heat transfer drying machine

Abstract

The present invention discloses a high-efficiency heat transfer tobacco drying machine. The main design concept of the present invention is to dry the tobacco to be dried, and use the high-temperature steam generated by the heat pump system to increase the temperature of the tobacco and adjust the moisture content of the tobacco. In addition, a second fan is used in the tank body to separate the tobacco, stems and debris impurities, thereby producing high-quality tobacco. In addition, the amount of steam and steam parameters input into the heating system are controlled based on the quality of the tobacco to be dried, ensuring that the moisture content of the dried tobacco is within the required range. The present invention organically combines high-temperature steam heating with tobacco drying, improves the heat and mass transfer efficiency, and greatly improves the thermal efficiency of the tobacco drying machine. At the same time, the direct contact between the high-temperature steam and the tobacco makes the heating process short and efficient. The moisture content of the tobacco at the outlet of the tobacco drying machine is feedback controlled, thereby ensuring the overall quality of the tobacco.

Description

Technical Field

[0001] The present invention relates to the field of cigarette manufacturing, and in particular to a high-efficiency heat transfer tobacco drying machine. Background Art

[0002] Tobacco drying is a crucial step in the cigarette-making process. Cut tobacco moisture content is controlled by using a cut tobacco dryer to raise its temperature, heat and humidify it, and remove moisture. Cut tobacco dryers are crucial equipment in cigarette factories, their primary tasks being to ensure the moisture content of cut tobacco meets the requirements of the cigarette-making process, improve its elasticity and filling value, and remove impurities. Currently, the most commonly used cut tobacco dryers are thin-plate dryers and tube-plate dryers.

[0003] Tobacco dryers use high-temperature steam as a heat source, heating the inner walls and the air passing through them. Condensed steam accumulates inside the dryer, causing a long startup time, impacting tobacco production. Furthermore, improper distribution of the high-temperature steam results in uneven temperatures within the dryer's sheet, causing tobacco to overheat and adhere to the walls, increasing the rejection rate. The heat exchange process between the tobacco and the high-temperature steam is significantly affected by time, resulting in relatively low heating efficiency. Summary of the Invention

[0004] In view of the above, the present invention aims to provide a high-efficiency heat transfer tobacco drying machine to solve the problems of low heating efficiency, long heating time and large fluctuations in tobacco quality of tobacco drying machines.

[0005] The technical solution adopted in the present invention is as follows:

[0006] The present invention provides a high-efficiency heat transfer tow-strip drying machine, comprising:

[0007] A first fan, a feed inlet, a conveying pipeline, a pipeline heating section, a tank, a second fan, and a discharge outlet, wherein the pipeline heating section includes a steam nozzle provided at the bottom of the pipeline and a heat pump system connected to the steam nozzle;

[0008] The first fan drives the tobacco shreds into the conveying pipe from the feed port, passes through the heating section of the pipe, and then enters the tank body. The second fan's negative pressure suction and the weight of the material separate the tobacco shreds, stems, and debris. The tobacco shreds with a preset moisture content are discharged from the top of the tank body through the discharge port to the tobacco drying machine; the remaining tobacco shreds, stems, and debris in the tank body are discharged through the bottom outlet of the tank body.

[0009] A moisture content sensor is provided at the discharge port, which is used to cooperate with the frequency converter of the second fan to adjust the working condition of the tofu drying machine according to process requirements.

[0010] In at least one possible implementation, the heat pump system includes a first compressor, a flash water tank, a water pump, a condenser, a second compressor, and an evaporator connected in sequence, and a mass flow meter is connected to one side of the pipeline between the first compressor and the steam nozzle.

[0011] In at least one possible implementation, the first compressor is a scroll compressor using carbon dioxide as the working fluid; and the second compressor is a twin-screw compressor.

[0012] In at least one possible implementation manner, a throttling mechanism is connected between the condenser and the evaporator, and a water replenishing mechanism is connected to one side of the flash water tank.

[0013] In at least one possible implementation, the first fan is an axial flow fan, and the second fan is a negative pressure centrifugal fan.

[0014] In at least one possible implementation manner, the delivery pipeline adopts a rectangular structure.

[0015] In at least one possible implementation manner, the thermal parameters of the steam ejected from the steam nozzle include: a temperature not lower than 150° C., and a pressure not lower than 0.8 MPa.

[0016] In at least one possible implementation manner, the negative pressure generated by the second fan is determined based on a preset moisture content of the cut tobacco.

[0017] The main design concept of the present invention is to dry the tobacco to be dried and use the high-temperature steam generated by the heat pump system to increase the temperature of the tobacco and adjust the moisture content of the tobacco. In addition, a second fan is used in the tank to separate the tobacco, stems, and debris impurities to produce high-quality tobacco. In addition, the amount of steam input and steam parameters of the heating system are controlled based on the quality of the tobacco to be dried to ensure that the moisture content of the dried tobacco is within the required range. The present invention organically combines high-temperature steam heating with tobacco drying to improve the heat and mass transfer efficiency and greatly enhance the thermal efficiency of the tobacco drying machine. At the same time, the direct contact between the high-temperature steam and the tobacco shortens the heating process and increases the efficiency. The feedback control of the moisture content of the tobacco at the tobacco drying machine outlet ensures the overall quality of the tobacco. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be further described below with reference to the accompanying drawings, in which:

[0019] Figure 1 A schematic structural diagram of a high-efficiency heat transfer tofu drying machine provided by an embodiment of the present invention;

[0020] Figure 2 A schematic cross-sectional view of a pipeline heating section provided in an embodiment of the present invention;

[0021] Figure 3 A schematic diagram of the working of the tank body provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0022] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0023] The present invention proposes an embodiment of a high-efficiency heat transfer tofu drying machine. Specifically, Figure 1 shown, including:

[0024] The system consists of a first fan (fan 1 in the figure), a feed inlet, a conveying pipeline, a pipeline heating section, a tank body, a second fan (fan 2 in the figure) and a discharge port. The pipeline heating section includes a steam nozzle located at the bottom of the pipeline and a heat pump system connected to the steam nozzle.

[0025] The first fan drives the tobacco shreds into the conveying pipe from the feed port, passes through the heating section of the pipe, and then enters the tank body. The second fan's suction effect and the weight of the material separate the tobacco shreds, stems, and debris. The tobacco shreds with a preset moisture content are discharged from the top of the tank body through the discharge port to the tobacco drying machine; the remaining tobacco shreds, stems, and debris in the tank body are discharged through the bottom outlet of the tank body.

[0026] A moisture content sensor is provided at the discharge port, which is used to cooperate with the frequency converter of the second fan to adjust the working condition of the tofu drying machine according to process requirements.

[0027] Furthermore, the heat pump system includes a first compressor (compressor 1 shown in the figure), a flash water tank, a water pump, a condenser, a second compressor (compressor 2 shown in the figure) and an evaporator connected in sequence, and a mass flow meter is connected to one side of the pipeline between the first compressor and the steam nozzle.

[0028] Based on this, the first compressor is a scroll compressor, and the working fluid used is carbon dioxide; the second compressor is a twin-screw compressor.

[0029] Based on this, the condenser is a water-cooled shell and tube heat exchanger, and the evaporator is an air-cooled fin and tube heat exchanger.

[0030] Based on this, a throttling mechanism is connected between the condenser and the evaporator, and a water replenishing mechanism is connected to one side of the flash water tank.

[0031] Furthermore, the first fan is an axial flow fan, and the second is a negative pressure centrifugal fan.

[0032] Furthermore, the delivery pipeline adopts a rectangular structure.

[0033] Preferably, the thermal parameters of the steam ejected from the steam nozzle include: a temperature not lower than 150° C., and a pressure not lower than 0.8 MPa.

[0034] Corresponding to the above embodiments, schematic descriptions are as follows:

[0035] After the tobacco to be dried enters the conveying duct, it is dispersed by fan 1 and transported along the conveying duct to the heating section. Specifically, the tobacco entering the dryer through the feed inlet is driven by an axial flow fan (first fan) located on one side of the rectangular conveying duct, blowing it apart and evenly distributing it throughout the conveying duct.

[0036] Then, the tobacco entering the heating section is heated by high temperature steam. Specifically, Figure 2 As shown, high-temperature steam is injected into the heating section of the pipe by multiple groups of nozzles arranged below the lower wall of the pipe heating section. The steam with a certain high pressure can ensure that the tobacco is in a floating state (suspended in the middle of the upper, lower, left and right walls of the pipe), avoiding accumulation on the wall of the conveying pipe. High-temperature steam is steam with a certain degree of superheat. In actual operation, the preferred steam thermal parameters can be: steam temperature not less than 150°C, and pressure not less than 0.8MPa. The specific adjustment of the high-temperature steam thermal parameters is determined by the condenser temperature of the heat pump system and the first compressor (compressor 1 in the figure). That is, when the heating load of the tobacco drying machine needs to be adjusted, it is achieved by adjusting the heat supply of the heat pump system and the speed of the compressor. At the same time, it can be monitored by the mass flow meter located on the side of the first compressor.

[0037] Specifically, the heat pump system is an air-source heat pump system that utilizes an air-cooled fin-and-tube evaporator, a scroll refrigeration compressor, a water-cooled jacketed condenser, and a throttling mechanism, using carbon dioxide as the refrigerant. The heat pump system first generates hot water exceeding 95°C, which enters a flash water tank to generate steam. This steam is compressed by the first compressor and then flows into the steam nozzle in the heating section.

[0038] When the operating conditions of the tobacco dryer change, the moisture content of the outlet tobacco is collected through a moisture sensor located at the outlet. The fan speed is regulated by the inverter controlling the second fan, and the steam flow and thermal parameters are controlled in conjunction with the mass flow meter on the rear side of the first compressor:

[0039] That is, when the moisture content of the tobacco at the outlet needs to change, the moisture content sensor at the outlet controls the frequency converter to change the speed of fan 2, thereby adjusting the moisture content of the tobacco at the tank outlet. Simultaneously, the speed of compressor 1 and the operation of the heat pump system are adjusted by calculating the heating power required by the moisture content change. The mass flowmeter located behind compressor 1 monitors and adjusts the thermal parameters and flow rate of the steam entering the steam nozzle. Similarly, when the mass flow rate of tobacco entering the tobacco dryer changes, the moisture content sensor at the outlet can also be used to control the speed of compressor 1 and the operation of the heat pump system by calculating the heating power required by the moisture content change. The mass flowmeter located behind compressor 1 monitors and adjusts the thermal parameters and flow rate of the steam entering the steam nozzle.

[0040] Continuing from the previous article, Figure 3 As shown, the heated tobacco enters the tank. Due to the increased volume of the tank relative to the conveying pipeline, the gravity of the material, the disturbance of the first fan, and the negative pressure generated by the centrifugal fan (second fan) installed on the top of the tank, the tobacco, stems, and impurities are separated in the tank. Tobacco that meets the established moisture content requirements is extracted from the top and output to the tobacco drying machine through the discharge port. Tobacco that cannot be sucked out, as well as the separated stems and impurities, gradually settle to the bottom of the tank and are discharged from the tank discharge port. It should be noted that the negative pressure generated by the second fan is determined by the moisture content of the tobacco. That is, when the suction force is set, tobacco that meets the preset moisture content requirement can be sucked out by the second fan.

[0041] In summary, the main design concept of the present invention is to dry the tobacco to be dried, and use the high-temperature steam generated by the heat pump system to increase the temperature of the tobacco and adjust the moisture content of the tobacco, and cooperate with the second fan in the tank to complete the separation of tobacco, stems and debris impurities to produce high-quality tobacco; in addition, based on the quality of the tobacco to be dried, the amount of steam and steam parameters input into the heating system are controlled to ensure that the moisture content of the dried tobacco is within the required range. The present invention organically combines high-temperature steam heating with tobacco drying, improves the heat and mass transfer efficiency, and greatly improves the thermal efficiency of the tobacco drying machine. At the same time, the direct contact between high-temperature steam and tobacco makes the heating process short and efficient, and the moisture content of the tobacco at the outlet of the tobacco drying machine is feedback controlled to ensure the overall quality of the tobacco.

[0042] In the embodiment of the present invention, "at least one" refers to one or more, and "more" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent the existence of A alone, the existence of A and B at the same time, and the existence of B alone. A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b and c can be represented by: a, b, c, a and b, a and c, b and c, or a, b and c, where a, b, c can be single or multiple.

[0043] The above describes in detail the structure, features and effects of the present invention based on the embodiments shown in the drawings, but the above is only a preferred embodiment of the present invention. It should be noted that the technical features involved in the above embodiments and their preferred modes can be reasonably combined and matched into a variety of equivalent schemes by those skilled in the art without departing from or changing the design ideas and technical effects of the present invention; therefore, the scope of implementation of the present invention is not limited to what is shown in the drawings. Any changes made in accordance with the concept of the present invention, or modifications to equivalent embodiments with equivalent changes, which still do not exceed the spirit covered by the description and drawings, should be within the scope of protection of the present invention.

Claims

1. A high-efficiency heat transfer wire drying machine, characterized in that: include: A first fan, a feed inlet, a conveying pipeline, a pipeline heating section, a tank, a second fan, and a discharge outlet, wherein the pipeline heating section includes a steam nozzle provided at the bottom of the pipeline and a heat pump system connected to the steam nozzle; The first fan breaks up and drives the tobacco into the conveying pipe from the feed port, passes through the heating section of the pipe, and then enters the tank body. The second fan's negative pressure suction effect and the weight of the material separate the tobacco, stems, and debris. The tobacco with a preset moisture content is discharged from the top of the tank body through the discharge port to the tobacco drying machine; the remaining tobacco, stems, and debris in the tank body are discharged through the bottom outlet of the tank body. A moisture content sensor is provided at the discharge port, which is used to cooperate with the frequency converter of the second fan to regulate the working conditions of the tobacco drying machine according to process requirements, including: controlling the moisture content sensor at the discharge port, adjusting the moisture content of the tobacco fed into the tank outlet by changing the speed of the second fan, and the negative pressure generated by the second fan is determined based on the preset moisture content of the tobacco.

2. The high-efficiency heat transfer tow-strip drying machine according to claim 1, characterized in that: The heat pump system includes a first compressor, a flash water tank, a water pump, a condenser, a second compressor and an evaporator connected in sequence, and a mass flow meter is connected to one side of the pipeline between the first compressor and the steam nozzle.

3. The high-efficiency heat transfer tow-steel drying machine according to claim 2, characterized in that: The first compressor is a scroll compressor, and the working fluid used is carbon dioxide; the second compressor is a twin-screw compressor.

4. The high-efficiency heat transfer tofu drying machine according to claim 2, characterized in that: A throttling mechanism is connected between the condenser and the evaporator, and a water replenishing mechanism is connected to one side of the flash water tank.

5. The high-efficiency heat transfer tofu drying machine according to claim 1, characterized in that: The first fan is an axial flow fan, and the second is a negative pressure centrifugal fan.

6. The high-efficiency heat transfer tofu drying machine according to claim 1, characterized in that: The conveying pipeline adopts a rectangular structure.

7. The high-efficiency heat transfer tofu drying machine according to claim 1, characterized in that: The thermal parameters of the steam ejected from the steam nozzle include: a temperature not lower than 150° C. and a pressure not lower than 0.8 MPa.

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