A low-temperature recycling type high-efficiency energy-saving grain dryer

Abstract

The present invention relates to the technical field of grain drying equipment, and particularly relates to a low-temperature recycling and highly energy-saving grain dryer, which includes an air inlet channel, an air outlet channel, a cyclone filtration mechanism, and an adsorption filtration mechanism; the air inlet channel is connected to an air inlet system; the air outlet channel is connected to an exhaust system; the cyclone filtration mechanism is arranged in the air outlet channel; the adsorption filtration mechanism is connected to the cyclone filtration mechanism; by separating moisture and dust particles in the high-temperature waste gas and directly introducing them to the position of the evaporator, heating the evaporator and then introducing it into the heat exchanger for heating, the filtered and heated gas will flow through the outer surface of the channel through which the waste gas passes to transfer its excess heat to the waste gas, realizing waste heat recovery and controlling the temperature of the gas entering the drying tower to be appropriate; it solves the problem that when there is dust in the grain, the hot and humid waste gas after drying will carry the dust out, and the waste gas carrying dust will cause the heat exchange efficiency to gradually decrease during recycling.

Description

Technical Field

[0001] The present invention relates to the technical field of grain drying equipment, and particularly relates to a low-temperature recycling type high-efficiency energy-saving grain dryer. Background Art

[0002] A low-temperature circulation type grain dryer is a device that uses hot air circulation to dry grains. Low-temperature circulation drying can reduce the damage to the nutritional components, taste and appearance of grains caused by high temperature, and can adjust the temperature and humidity according to different crops to achieve the best drying effect.

[0003] Currently, low-temperature circulation grain dryers mainly consist of a dryer body and a heat pump system. When circulating and drying grains such as wheat and rice that contain dust and impurities, the dust therein will be discharged together with the waste gas. When recycling the waste gas, the dust in the waste gas will block the gaps between the fins of the evaporator, resulting in a decrease in the heat exchange efficiency of the evaporator. Therefore, when circulating and drying grains with a large amount of dust and impurities, the waste gas will be directly discharged without recovering and utilizing the waste heat, causing waste of thermal energy. In response to the above problems, the prior art has proposed a solution. A heat pump type low-temperature circulation grain dryer with recoverable waste heat, with the patent publication number CN108489251B, by setting an air heat exchanger, uses the waste gas to perform heat exchange on the cold air inhaled from the outside before the waste gas is discharged, so that the newly inhaled air from the outside can obtain heat. At this time, the heated new air is introduced to the evaporator position. Under the action of the heat of the new air, the refrigerant inside the evaporator will quickly evaporate, helping the heat pump system improve the working efficiency, recover and utilize the heat in the waste gas, improve the energy utilization rate, and save energy and protect the environment.

[0004] Although the prior art has solved the problem of being unable to recycle the waste heat in the waste gas during the circulating drying of grains with a large amount of dust and impurities, there are still the following problems: When the grains are circulating and drying, the waste gas will carry away the moisture in the grains. At this time, the discharged waste gas is high-temperature and high-humidity and carries dust. After the waste gas is introduced into the air heat exchanger, the dust carried therein will adhere to the inner cavity surface of the air exchanger. And due to the high humidity of the waste gas, the dust will be more likely to adhere to the inner cavity surface of the air exchanger at this time. On the one hand, with the deposition of dust, the flow area of air heat exchange will decrease, resulting in restricted air flow, causing equipment blockage, and thus affecting the normal heat exchange process. On the other hand, a layer of dirt will gradually form, which will hinder the heat transfer, resulting in a decrease in the heat exchange efficiency, making the waste heat recovery utilization rate low and unable to effectively save energy.

[0005] In view of the above situation, in order to overcome the above technical problems, the present invention proposes a low-temperature recycling type high-efficiency energy-saving grain dryer. Summary of the Invention

[0006] The present invention provides a low-temperature recycling type high-efficiency energy-saving grain dryer, which solves the problem that when there is dust in the grain, the hot and humid exhaust gas after drying will carry the dust and discharge it. When the hot and humid exhaust gas carrying dust is recycled, the heat exchange efficiency will gradually decrease. By separating the moisture and dust particles in the high-temperature exhaust gas and directly introducing them to the position of the evaporator, after heating the evaporator, it is then introduced into the heat exchanger for heating. Since the temperature of the heated gas after heat exchange is higher than the suitable temperature for grain drying, the filtered and heated gas is guided to the outer surface of the channel through which the exhaust gas passes, and its excess heat is transferred to the exhaust gas, realizing waste heat recovery and controlling the temperature of the gas entering the drying tower to be appropriate.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] A low-temperature recycling type high-efficiency energy-saving grain dryer includes a drying tower, a feeding system and an air inlet system; it also includes an exhaust system, a heating system and a circulation air duct; the exhaust system is connected to the drying tower; the heating system is connected to the air inlet system through the circulation air duct; the circulation air duct includes an air inlet channel, an air outlet channel, a swirl filtration mechanism and an adsorption filtration mechanism; the air inlet channel is connected to the air inlet system; the air outlet channel is connected to the exhaust system, and the air outlet channel passes through the inside of the air inlet channel, and the exhaust gas flows out from the exhaust system and enters the air outlet channel; the swirl filtration mechanism is connected to the air outlet channel; the adsorption filtration mechanism is connected to the swirl filtration mechanism, the exhaust gas flows through the swirl filtration mechanism from the air outlet channel and then enters the adsorption filtration mechanism, and the exhaust gas flowing out from the adsorption filtration mechanism will flow into the heating system, and finally the filtered exhaust gas enters the air inlet channel from the heating system and flows through the outer surface of the air outlet channel.

[0009] Preferably, the air outlet channel includes a connection section, a heating section and an outflow section; the connection section is connected to the exhaust system; the heating section is arranged inside the air inlet channel; the outflow section is connected to the heating system.

[0010] In the above solution, by arranging the waste air outlet channel inside the air inlet channel, the heat overflowing during the flowing process of the heated gas can be fully utilized before the heated gas enters the drying tower. The overflowing heat is used to heat the exhaust gas and the fresh gas introduced from the outside, so that the exhaust gas and the fresh gas can reach the heating system at a higher temperature, enabling the refrigerant in the evaporator to evaporate quickly and improving the circulation efficiency; and the temperature of the gas after heat exchange in the heating system is about 50 - 80 degrees, and the gas temperature needs to be controlled at about 40 - 50 degrees before being introduced into the drying tower. At this time, the excess heat can be used to heat the newly introduced gas and the exhaust gas, so that the heat can be fully recovered and utilized.

[0011] Preferably, the heating system includes a housing, an evaporator, a compressor, a condenser, and a heat exchanger; the housing is connected to the outflow section; the evaporator is disposed within the housing, and the outlet position of the outflow section is directly opposite the position where the evaporator is located; the compressor is connected to the evaporator; the condenser is connected to the evaporator; the heat exchanger is connected between the compressor and the condenser.

[0012] In the above solution, the gas after mixing the exhausted gas that has completed filtration and dehumidification and the heated fresh air is introduced to the position of the evaporator, thereby helping the refrigerant in the evaporator to evaporate quickly, and thus ensuring the evaporation efficiency even in a cold environment. Moreover, the filtered exhausted gas is directly used to contact the evaporator instead of exchanging heat with the freshly introduced air from the outside, further avoiding heat loss caused by heat exchange and improving the utilization rate of waste heat.

[0013] Preferably, the exhaust system includes an exhaust gas pipe and an air extraction impeller; the exhaust gas pipe is connected between the drying tower and the connection section; the air extraction impeller is disposed at the connection position of the exhaust gas pipe and the connection section; the cyclone filtration mechanism includes a cyclone chamber, an ash accumulation tank, and a riser pipe; the cyclone chamber is connected to the air outlet channel; the ash accumulation tank is disposed below the cyclone chamber; the riser pipe is disposed above the center of the cyclone chamber; the connection section includes a hot channel and a cold channel; the hot channel is tangentially connected to the upper part of the cyclone chamber; the cold channel is tangentially connected to the middle part of the cyclone chamber.

[0014] In the above solution, the structure of the cyclone separator can preliminarily separate the dust impurities and moisture in the exhaust gas. And compared with an ordinary cyclone separator, here the low-temperature air is introduced into the middle part of the cyclone chamber, and the high-temperature exhaust gas is introduced into the upper part of the cyclone chamber. On the one hand, a temperature difference is formed between the upper layer and the lower layer of the cyclone chamber. The temperature of the upper layer is high, and the density of the moisture separated from the high-temperature exhaust gas at the upper layer position decreases. At this time, when the high-temperature exhaust gas rotates downward along the inner wall of the cyclone chamber, it will be easier to drive the water droplets downward, and the water droplets will drive the dust downward together, making the moisture and dust accelerate into the ash accumulation tank, so that the gas flowing out of the cyclone filtration mechanism is drier and does not carry dust. On the other hand, compared with the freshly introduced air from the outside, there is more dust and moisture in the high-temperature exhaust gas. Introducing it from the upper layer can extend its cyclone path, making the separation of dust and moisture more thorough.

[0015] Preferably, the upper part of the riser pipe is connected to the heating section; the air inlet channel is connected to the upper part of the cyclone chamber.

[0016] In the above solution, the heat in the air inlet passage is used to further heat the upper part of the cyclone chamber, so that heat accumulation can be formed in the upper part of the cyclone chamber, thereby ensuring the temperature difference between the upper and lower parts of the cyclone chamber. When the high-temperature waste gas reaches the lower layer of the cyclone chamber and meets the low-temperature air entering from the outside, it can be quickly condensed, and then all the moisture in the gas can be thrown out under the action of swirling, so as to further improve the separation effect.

[0017] Preferably, the adsorption and filtration mechanism includes an activated carbon layer and a swirl plate; the activated carbon layer is arranged in the riser pipe; the swirl plate is arranged below the activated carbon layer.

[0018] In the above solution, the moisture in the high-temperature gas is adsorbed by the high-temperature resistant activated carbon layer. Compared with using the condensation method to filter out the moisture in the gas, the use of activated carbon filtration has less influence on the heat in the gas, can reduce heat loss, and thus improve the utilization rate of heat; and under the action of the previous cyclone separation, most of the moisture and dust can be separated, thereby reducing the adsorption burden of the activated carbon and enabling the activated carbon to work for a long time; the adsorption effect of the activated carbon will be significantly improved when the temperature rises, so the activated carbon layer located in the upper part of the cyclone chamber can improve the adsorption effect, so as to absorb all the moisture and dust particles in the waste gas and fresh gas. The swirling plate makes the rising gas form a swirl, making the gas entering the activated carbon layer more uniform and improving the filtration effect.

[0019] Preferably, the air inlet passage includes a recovery section and an output section; one end of the recovery section is connected to the housing, and the other end is connected to the heat exchanger; one end of the output section is connected to the heat exchanger, and the other end is connected to the air inlet system.

[0020] In the above solution, since the air outlet passage leads the filtered gas to the position where the evaporator is located to help the evaporator quickly evaporate the refrigerant, after the gas passes through the evaporator and heats its fins, the gas will enter the heat exchanger from the recovery section, so that the gas will be heated again in the heat exchanger. Since the gas temperature is relatively high itself, at this time, the residence time of the gas in the heat exchanger can be shortened and it can quickly enter the drying tower. On the one hand, it can save heat energy loss, and on the other hand, it can accelerate the gas circulation speed, thereby improving the drying efficiency of the grains.

[0021] Preferably, a sealing cavity is arranged in the housing; the evaporator is arranged in the sealing cavity; both side walls of the sealing cavity are respectively connected to the outflow section and the recovery section.

[0022] In the above solution, by arranging the evaporator in a sealed cavity, the filtered gas enters the sealed cavity. On the one hand, it avoids the high-temperature gas after filtration from affecting the normal operation of other equipment. On the other hand, it can reduce the heat transfer of this gas to other components, further avoiding heat loss, thereby improving the heat utilization rate and achieving the purpose of energy conservation.

[0023] The beneficial effects of the present invention are as follows:

[0024] 1. Compared with the existing low-temperature circulating grain dryer, in the present invention, the waste gas and fresh gas are introduced into the cyclone chamber to separate the moisture and dust particles in the waste gas. And during the separation process, since the waste gas enters from the upper layer and the fresh gas enters from the lower layer, on the one hand, it can form a temperature difference between the upper and lower layers of the cyclone chamber, thereby improving the moisture separation effect and ensuring that the gas reaching the evaporator and the drying tower subsequently is dry, ensuring the waste heat recovery effect and the grain drying effect. On the other hand, the high-humidity waste gas carrying a large amount of dust enters the cyclone chamber from the upper layer, and its swirling path is longer and the separation time is longer, which can effectively separate the moisture and dust, ensure that the surface of the evaporator does not scale, improve the evaporation speed of the evaporator, and enable the waste heat to be fully recovered and utilized, achieving the purpose of energy conservation.

[0025] 2. In the present invention, after filtering the waste gas, it is directly introduced to the position of the evaporator to help the evaporator evaporate quickly. And after flowing through the evaporator, it will enter the heat exchanger for heating, and then enter the drying tower after heating. Since the moisture and dust content in the filtered waste gas is extremely low, it can further improve the grain drying effect, taking away all the moisture and dust in the grain. And because the filtered waste gas is still at a relatively high temperature, it can shorten its exchange time in the heat exchanger. On the one hand, it can effectively improve the circulating speed of the grain drying cycle, improve the grain drying efficiency and drying effect. On the other hand, it can reduce heat energy loss, enable the heat generated by each compression of the compressor to supply multiple cycles, and further enhance the energy-saving effect.

[0026] 3. In the present invention, the channel through which the gas flows after being heated by the heat exchanger is arranged outside the channel after the waste gas is filtered. Since the filtered gas is a mixed gas of high-temperature waste gas and low-temperature fresh gas from the outside, its temperature will decrease to a certain extent. And the temperature of the gas after being heated by the heat exchanger is usually higher than the temperature that can be directly introduced into the drying tower. At this time, it is necessary to cool the heated gas, and its excess heat will be transferred to the filtered mixed gas when passing through the outside of the air outlet channel, enabling this mixed gas to help the evaporator evaporate quickly when reaching the position of the evaporator, improving the speed of the drying cycle, thereby improving the drying effect, and recovering all the waste heat generated in the overall drying cycle, improving the energy-saving effect. Description of the Drawings

[0027] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0028] Figure 1 is the overall structure diagram of the present invention;

[0029] Figure 2 is the internal structure diagram of the cyclone filtration mechanism of the present invention;

[0030] Figure 3 is the schematic structural diagram of the heating system of the present invention;

[0031] Figure 4 is the position relationship diagram of the heating section and the output section of the present invention;

[0032] Figure 5 is Figure 3 the enlarged structure diagram at position A in;

[0033] Figure 6 is the schematic structural diagram of the exhaust system of the present invention;

[0034] Figure 7 is Figure 3 the enlarged structure diagram at position B in;

[0035] Figure 8 is the diagram of different gas flow directions in the present invention;

[0036] In the figure: 1, drying tower; 2, feeding system; 3, air inlet system; 4, exhaust system; 41, waste gas pipeline; 42, exhaust impeller; 5, heating system; 51, housing; 511, sealing cavity; 52, evaporator; 53, compressor; 54, condenser; 55, heat exchanger; 6, circulation air duct; 61, air inlet channel; 611, recovery section; 612, output section; 62, air outlet channel; 621, connection section; 6211, hot channel; 6212, cold channel; 622, heating section; 623, outflow section; 63, cyclone filtration mechanism; 631, cyclone cavity; 632, dust accumulation tank; 633, riser; 64, adsorption filtration mechanism; 641, activated carbon layer; 642, cyclone plate. Specific Embodiments

[0037] To better understand the above technical solutions, the following will describe the above technical solutions in detail in conjunction with the accompanying drawings of the specification and specific embodiments.

[0038] Please refer to Figures 1 to 8, the present invention provides a low-temperature recycling type high-efficiency energy-saving grain dryer, and the technical solution is as follows:

[0039] As a specific embodiment of the present invention, referring to Figure 1 and Figure 2 , a low-temperature recycling type high-efficiency energy-saving grain dryer, includes a drying tower 1, a feeding system 2 and an air inlet system 3; it also includes an exhaust system 4, a heating system 5 and a circulation air duct 6; the exhaust system 4 is connected to the drying tower 1; the heating system 5 is connected to the air inlet system 3 through the circulation air duct 6; the circulation air duct 6 includes an air inlet channel 61, an air outlet channel 62, a cyclone filtering mechanism 63 and an adsorption filtering mechanism 64; the air inlet channel 61 is connected to the air inlet system 3; the air outlet channel 62 is connected to the exhaust system 4, and the air outlet channel 62 penetrates inside the air inlet channel 61, and the waste gas flows out from the exhaust system 4 and enters the air outlet channel 62; the cyclone filtering mechanism 63 is connected to the air outlet channel 62; the adsorption filtering mechanism 64 is connected to the cyclone filtering mechanism 63, the waste gas flows through the cyclone filtering mechanism 63 from the air outlet channel 62 and then enters the adsorption filtering mechanism 64, and the waste gas flowing out from the adsorption filtering mechanism 64 will flow into the heating system 5, and finally the filtered waste gas enters the air inlet channel 61 from the heating system 5 and flows through the outer surface of the air outlet channel 62. Since the temperature of the heated gas is relatively high, it needs to be cooled to a suitable temperature for grain drying before being introduced into the drying tower 1. At this time, when flowing through the outer surface of the air outlet channel 62, the excess heat can be fully utilized, and the excess heat is transferred to the filtered waste gas, so that it can help the heating system 5 improve the heating cycle speed.

[0040] As a specific embodiment of the present invention, referring to Figure 2 and Figure 3 , the air outlet channel 62 includes a connection section 621, a heating section 622 and an outflow section 623; the connection section 621 is connected to the exhaust system 4; the heating section 622 is arranged inside the air inlet channel 61; the outflow section 623 is connected to the heating system 5. By arranging the waste gas outlet channel inside the air inlet channel 61, the excess heat overflowing during the flowing process of the heated gas can be fully utilized before entering the drying tower 1, and the overflowing heat is used to heat the waste gas and the fresh gas introduced from the outside, so that the waste gas and the fresh gas can reach the heating system 5 at a higher temperature, enabling the refrigerant in the evaporator 52 to evaporate quickly and improving the circulation efficiency; and the temperature of the gas after heat exchange in the heating system 5 is about 50 - 80 degrees, and the gas temperature needs to be controlled at about 40 - 50 degrees before being introduced into the drying tower 1. At this time, the excess heat can be used to heat the newly introduced gas and the waste gas, so that the heat can be fully recovered and utilized.

[0041] As a specific embodiment of the present invention, referring toFigure 2 , Figure 3 and Figure 4 , the heating system 5 includes a housing 51, an evaporator 52, a compressor 53, a condenser 54, and a heat exchanger 55; the housing 51 is connected to the outflow section 623; the evaporator 52 is disposed within the housing 51, and the outlet position of the outflow section 623 is directly opposite the position where the evaporator 52 is located; the compressor 53 is connected to the evaporator 52; the condenser 54 is connected to the evaporator 52; the heat exchanger 55 is connected between the compressor 53 and the condenser 54. By introducing the gas after mixing the exhausted gas that has completed filtration and dehumidification and the heated fresh gas to the position of the evaporator 52, it helps the refrigerant in the evaporator 52 to quickly evaporate, thereby ensuring the evaporation efficiency even in a cold environment. Moreover, the filtered exhausted gas is directly used to contact the evaporator 52 instead of exchanging heat with the freshly introduced gas from the outside, further avoiding heat loss caused by heat exchange and improving the utilization rate of waste heat.

[0042] As a specific embodiment of the present invention, referring to Figure 3 , Figure 5 , Figure 6 and Figure 8, the exhaust system 4 includes an exhaust gas pipeline 41 and an air extraction impeller 42; the exhaust gas pipeline 41 is connected between the drying tower 1 and the connection section 621; the air extraction impeller 42 is arranged at the connection position of the exhaust gas pipeline 41 and the connection section 621. There are two groups of impellers of the air extraction impeller 42 arranged on the same shaft. These two groups of impellers are respectively used to guide the exhaust gas and extract fresh outside air. The two groups of impellers are separated by the connection section 621. Therefore, the exhaust gas and the fresh air enter different channels respectively without affecting each other; the cyclone filtration mechanism 63 includes a cyclone chamber 631, an ash accumulation tank 632 and a riser 633; the cyclone chamber 631 is connected to the air outlet channel 62; the ash accumulation tank 632 is arranged below the cyclone chamber 631; the riser 633 is arranged at the upper part of the center of the cyclone chamber 631; the connection section 621 includes a hot channel 6211 and a cold channel 6212; the hot channel 6211 is tangentially connected to the upper part of the cyclone chamber 631; the cold channel 6212 is tangentially connected to the middle part of the cyclone chamber 631; under the action of the tangential connection, the exhaust gas and the fresh air can form a swirling downward flow trend when entering the cyclone chamber 631. At this time, the exhaust gas and the fresh air will be separated from moisture and dust under the action of centrifugal force. Through the structure of the cyclone chamber 631 similar to a cyclone separator, the dust impurities and moisture in the exhaust gas can be preliminarily separated. After the separation is completed, the clean and dry gas will be discharged through the riser 633 in the center. And compared with an ordinary cyclone separator, the low-temperature air is introduced into the middle part of the cyclone chamber 631 here, and the high-temperature exhaust gas is introduced into the upper part of the cyclone chamber 631. On the one hand, a temperature difference is formed between the upper layer and the lower layer of the cyclone chamber 631. The upper layer has a high temperature, and the density of the moisture separated from the high-temperature exhaust gas at the upper layer position decreases. At this time, when the high-temperature exhaust gas rotates downward along the inner wall of the cyclone chamber 631, it will be easier to drive the water droplets downward, and the water droplets will drive the dust to flow downward together, so that the moisture and dust are accelerated into the ash accumulation tank 632, ensuring that the separated exhaust gas will not carry the moisture and dust upward again, making the gas flowing out of the cyclone filtration mechanism 63 drier and dust-free. On the other hand, compared with the fresh air entering from the outside, there is more dust and moisture in the high-temperature exhaust gas. Entering from the upper layer can extend its swirling path, making the separation of dust and moisture more thorough.

[0043] As a specific embodiment of the present invention, referring to Figure 3 and Figure 8, the upper part of the riser tube 633 is connected to the heating section 622; the air inlet passage 61 is connected to the upper part of the swirl chamber 631. The heat in the air inlet passage 61 is used to further heat the upper part of the swirl chamber 631, so that heat accumulation can be formed in the upper part of the swirl chamber 631, thereby ensuring the temperature difference between the upper and lower parts of the swirl chamber 631. When the high-temperature exhaust gas reaches the lower layer of the swirl chamber 631 and meets the low-temperature air entering from the outside, it can be quickly condensed. Furthermore, all the moisture in the gas can be thrown out under the swirl action, so that the separation effect is further improved. The height of the swirl chamber 631 can be designed according to the different moisture contents to be separated. When used for drying grains with a high moisture content, the height of the swirl chamber 631 can be increased, so as to extend the separation time and achieve the effect of improving the separation effect.

[0044] As a specific embodiment of the present invention, referring to Figure 3 , Figure 5 and Figure 8 , the adsorption and filtration mechanism 64 includes an activated carbon layer 641 and a swirl plate 642; the activated carbon layer 641 is arranged in the riser tube 633; the swirl plate 642 is arranged below the activated carbon layer 641. The moisture in the high-temperature gas is adsorbed by the high-temperature-resistant activated carbon layer 641. Compared with using the condensation method to filter out the moisture in the gas, using activated carbon filtration has less influence on the heat in the gas and can reduce heat loss, thereby improving the heat utilization rate; and under the action of the previous cyclone separation, most of the moisture and dust can be separated, thus reducing the adsorption burden on the activated carbon and enabling the activated carbon to work for a long time; the adsorption effect of the activated carbon will be significantly improved when the temperature rises, so the activated carbon layer 641 located at the upper part of the swirl chamber 631 can improve the adsorption effect, thereby absorbing all the moisture and dust particles in the exhaust gas and fresh gas. The swirl plate 642 makes the rising gas form a swirl, so that the distribution of the gas when entering the activated carbon layer 641 is more uniform and the filtration effect is improved; through the cooperation of the adsorption effect of the activated carbon layer 641 and the swirl filtration mechanism 63, it can prevent part of the moisture from escaping in the gas that rises again after reaching the bottom of the swirl chamber 631.

[0045] As a specific embodiment of the present invention, referring to Figure 3 , Figure 4 and Figure 7, the air inlet passage 61 includes a recovery section 611 and an output section 612; one end of the recovery section 611 is connected to the housing 51, and the other end is connected to the heat exchanger 55; one end of the output section 612 is connected to the heat exchanger 55, and the other end is connected to the air inlet system 3. Since the air outlet passage 62 passes the filtered gas to the position where the evaporator 52 is located to help the evaporator 52 quickly evaporate the refrigerant, after the gas passes through the evaporator 52 and heats its fins, the gas will enter the heat exchanger 55 from the recovery section 611, so that the gas will be heated again in the heat exchanger 55. Since the gas temperature is relatively high itself, at this time, the residence time of the gas in the heat exchanger 55 can be shortened and it can quickly enter the drying tower 1. On the one hand, it can save heat energy loss, and on the other hand, it can accelerate the gas circulation speed, thereby improving the drying efficiency of the grains.

[0046] As a specific embodiment of the present invention, referring to Figure 3 , Figure 4 and Figure 7 , a sealing cavity 511 is provided in the housing 51; both side walls of the sealing cavity 511 are respectively connected to the outflow section 623 and the recovery section 611; the evaporator 52 is arranged in the sealing cavity 511. By arranging the evaporator 52 in the sealing cavity 511, the filtered gas enters the sealing cavity 511. On the one hand, it avoids the higher-temperature filtered gas from affecting the normal operation of other equipment, and on the other hand, it can reduce the heat transfer of the gas to other components, further avoiding heat loss, thereby improving the heat utilization rate and achieving the purpose of saving. The inner surface of the sealing cavity 511 can be added with heat-insulating materials to avoid heat loss, so that the inside of the sealing cavity 511 can always be maintained at a relatively high temperature, so that the refrigerant in the evaporator 52 can be kept evaporating quickly, improving the circulation speed of the entire drying cycle, and thus improving the drying efficiency and drying effect of the grains.

[0047] Working process: The waste gas discharged from the drying tower 1 after drying enters the air outlet passage 62 through the exhaust system 4. The waste gas enters the swirl chamber 631 from the upper part of the swirl chamber 631 through the air outlet passage 62. Under the action of the air extraction impeller 42, fresh air from the outside enters the swirl chamber 631 from the middle of the swirl chamber 631; in the swirl chamber 631, the waste gas and the fresh air will separate the moisture and dust therein. The separated gas will pass through the adsorption and filtration mechanism 64 for further filtration. The filtered gas will flow to the evaporator 52 to help the evaporator 52 quickly evaporate the refrigerant, and then enter the heat exchanger 55 for heating. The heated gas flows through the outer surface of the heating section 622, transfers the excess heat to the filtered mixed gas, and enters the drying tower 1 after transferring the excess heat to complete the cycle.

[0048] Specifically, the exhaust gas discharged after drying in the drying tower 1 enters the exhaust gas pipeline 41. Under the action of the extraction impeller 42, the exhaust gas will enter the connection section 621. In order to separate the moisture and dust in the exhaust gas and supplement the gas lost during the drying process, the exhaust gas enters the upper part of the swirl chamber 631 through the hot channel 6211, and the fresh air from the outside enters the middle part of the swirl chamber 631 through the cold channel 6212. When the exhaust gas and the fresh air enter the swirl chamber 631, a swirling downward flow trend is formed. At this time, the exhaust gas and the fresh air will be separated from moisture and dust under the action of centrifugal force. The separated clean and dry gas will flow out of the swirl chamber 631 through the central riser 633. Since the exhaust gas entering from the upper part is high-temperature gas and the outside air entering from the middle part is low-temperature gas, a temperature difference will be formed between the upper part and the middle part of the swirl chamber 631, which can accelerate the condensation of the moisture in the high-temperature exhaust gas and drive the dust separated to the side wall of the swirl chamber 631 to quickly flow towards the dust accumulation tank 632, preventing the dust and moisture from escaping from the swirl chamber 631 along with the rising gas, thus ensuring the separation effect of the exhaust gas and the fresh air; In order to prevent the rising gas from carrying a small amount of moisture and dust, the rising gas will pass through the adsorption and filtration mechanism 64. During the rising process, the gas will form a swirl under the action of the swirl plate 642, so as to achieve the purpose of uniformly contacting the activated carbon layer 641, enabling the activated carbon layer 641 to filter out the remaining dust and moisture in the gas. And because the activated carbon layer 641 is located in the upper part of the swirl chamber 631 and at a relatively high temperature, its adsorption effect will be further improved;

[0049] Since the gas flowing out of the adsorption and filtration mechanism 64 is a mixture of high-temperature exhaust gas and low-temperature fresh air from the outside, its overall temperature will drop. The temperature of the gas after heat exchange in the heating system 5 is about 50 - 80 degrees Celsius. It is necessary to control the gas temperature to about 40 - 50 degrees Celsius before introducing it into the drying tower 1. In order to recover and utilize the excess heat of the heated gas and ensure that the filtered mixed gas can help the evaporator 52 quickly evaporate the refrigerant, the gas flowing out of the adsorption and filtration mechanism 64 will enter the heating section 622. The air inlet channel 61 through which the heated gas flows is sleeved outside the heating section 622. At this time, the heated gas will flow over the outer surface of the heating section 622, enabling the excess heat in the heated gas to be transferred to the filtered mixed gas, thereby recovering and utilizing all the excess heat in the entire drying cycle and improving the energy-saving effect. After absorbing the excess heat of the heated gas, the temperature of the filtered mixed gas rises. After flowing through the heating section 622, the mixed gas enters the sealing cavity 511, enabling the refrigerant in the evaporator 52 to quickly evaporate. After flowing over the surface of the evaporator 52, the mixed gas will enter the recovery section 611 and then enter the heat exchanger 55 through the recovery section 611 for heating. The heated gas enters the output section 612, flows over the outer surface of the heating section 622 to reduce the temperature to a suitable drying temperature, and then enters the drying tower 1 for the drying cycle.

[0050] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and the descriptions in the specification only illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of the present invention claimed is defined by the appended claims and their equivalents.

Claims

1. A low-temperature recycling type high-efficiency energy-saving grain dryer, comprising a drying tower (1), a feeding system (2) and an air intake system (3); characterized in that: The invention also comprises an exhaust system (4), a heating system (5) and a circulating air duct (6); the exhaust system (4) is connected to the drying tower (1); the heating system (5) is connected to the air inlet system (3) through the circulating air duct (6); the circulating air duct (6) comprises an air inlet channel (61), an air outlet channel (62), a cyclone filter mechanism (63) and an adsorption filter mechanism (64); the air inlet channel (61) is connected to the air inlet system (3); the air outlet channel (62) is connected to the exhaust system (4), and the air outlet channel (62) is arranged through the air inlet channel (61). Inside, the exhaust gas flows out of the exhaust system (4) and enters the air outlet channel (62); the cyclone filter mechanism (63) is connected to the air outlet channel (62); the adsorption filter mechanism (64) is connected to the center of the cyclone filter mechanism (63); the exhaust gas flows from the air outlet channel (62) through the cyclone filter mechanism (63) and then enters the adsorption filter mechanism (64); the exhaust gas flowing out of the adsorption filter mechanism (64) flows into the heating system (5); the filtered exhaust gas enters the air inlet channel (61) from the heating system (5) and flows through the outer surface of the air outlet channel (62); The air outlet channel (62) comprises a connecting section (621), a heating section (622) and an outflow section (623); the connecting section (621) is connected to the exhaust system (4); the heating section (622) is arranged inside the air inlet channel (61); the tail of the outflow section (623) is connected to the heating system (5); The exhaust system (4) comprises an exhaust gas pipeline (41) and an exhaust impeller (42); the exhaust gas pipeline (41) is connected between the drying tower (1) and the connecting section (621); the exhaust impeller (42) is arranged at the connecting position of the exhaust gas pipeline (41) and the connecting section (621); the cyclone filtering mechanism (63) comprises a cyclone chamber (631), an ash accumulation tank (632) and a riser (633); the cyclone chamber (631) and The ash accumulation groove (632) is arranged below the swirl chamber (631); the riser (633) is arranged at the upper part of the center of the swirl chamber (631); the connecting section (621) comprises a hot channel (6211) and a cold channel (6212); the hot channel (6211) is tangentially connected to the upper part of the swirl chamber (631); and the cold channel (6212) is tangentially connected to the middle part of the swirl chamber (631).

2. The low-temperature recycling type high-efficiency energy-saving grain dryer according to claim 1 is characterized in that: The heating system (5) comprises a shell (51), an evaporator (52), a compressor (53), a condenser (54) and a heat exchanger (55); the shell (51) is connected to an outflow section (623); the evaporator (52) is arranged in the shell (51), and the outlet position of the outflow section (623) is directly opposite to the position of the evaporator (52); the compressor (53) is connected to the evaporator (52); the condenser (54) is connected to the evaporator (52); and the heat exchanger (55) is connected between the compressor (53) and the condenser (54).

3. The low-temperature recycling type high-efficiency energy-saving grain dryer according to claim 1 is characterized in that: The upper portion of the ascending pipe (633) is connected to the heating section (622); and the air inlet channel (61) is connected to the upper portion of the swirl chamber (631).

4. A low-temperature recycling type high-efficiency energy-saving grain dryer according to claim 3, characterized in that: The adsorption and filtering mechanism (64) comprises an activated carbon layer (641) and a cyclone plate (642); the activated carbon layer (641) is arranged in the riser (633); and the cyclone plate (642) is arranged below the activated carbon layer (641).

5. The low-temperature recycling type high-efficiency energy-saving grain dryer according to claim 2 is characterized in that: The air inlet channel (61) comprises a recovery section (611) and an output section (612); one end of the recovery section (611) is connected to the shell (51), and the other end is connected to the heat exchanger (55); one end of the output section (612) is connected to the heat exchanger (55), and the other end is connected to the air inlet system (3).

6. A low-temperature recycling type high-efficiency energy-saving grain dryer according to claim 5, characterized in that: A sealed cavity (511) is provided in the shell (51); two side walls of the sealed cavity (511) are respectively connected to the outflow section (623) and the recovery section (611); and the evaporator (52) is provided in the sealed cavity (511).

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