A contact heat pump dryer

Abstract

The present invention relates to a contact heat pump dryer, comprising a drying bin, a heat exchanger is arranged in the drying bin, a material feed port is arranged on the end surface of the drying bin, a material discharge port is arranged on the bottom surface of the drying bin, an air inlet duct and an air exhaust duct are arranged on the side walls of the drying bin respectively, the drying bin is rotatably arranged on a support frame, the drying bin is rotated on the support frame by a first driving device, a compressor, a filter, an electronic expansion valve, an evaporator and a compressor are arranged outside the drying bin; the drying bin rotates around the heat exchanger along an axis; electric valves are arranged between the material feed port and the drying bin, between the material discharge port and the drying bin, and in the air inlet duct; a temperature and humidity sensor is arranged in the drying bin, a controller is arranged on the outer wall of the drying bin, and the controller is electrically connected to the temperature and humidity sensor, the electric valve, the first suction fan and the first driving device respectively. The present invention has the advantages of strong practicability and simple structure.

Description

Technical Field

[0001] The invention relates to the technical field of drying equipment, in particular to a contact type heat pump drying machine. Background Art

[0002] As a clean, environmentally friendly and efficient energy conversion device, heat pumps are increasingly used in the crop drying process. However, most heat pump dryers on the market heat the air to form high-temperature hot air to dry the materials to be dried, which is equivalent to secondary heat exchange, increasing the heat transfer temperature difference and virtually reducing the energy efficiency of the heat pump. In the present invention, heat exchange is carried out by direct contact between the material and the heat exchanger pipe and fins, which can fully utilize the heat generated by the heat pump system, reduce energy waste, and improve the overall energy efficiency of the system.

[0003] At present, most heat pumps on the market use non-environmentally friendly refrigerants such as R22, R134a, and R410a. Once leaked, they will pollute the dried materials. The present invention uses natural refrigerant carbon dioxide or other environmentally friendly refrigerants, which are colorless, odorless, and non-toxic. Even if leaked, there is zero pollution. In addition, the drying temperature of the carbon dioxide heat pump is higher than that of other refrigerants, which is very conducive to drying. Summary of the invention

[0004] The object of the present invention is to provide a contact type heat pump drying machine.

[0005] In order to solve the above problems, a contact heat pump dryer includes a drying chamber, a heat exchanger is provided in the drying chamber, a feed port is provided on the end surface of the drying chamber, a discharge port is provided on the bottom surface of the drying chamber, an air inlet duct and an exhaust duct are respectively provided on the side walls of the drying chamber, and a first suction fan is provided in the exhaust duct.

[0006] The drying bin is rotatably arranged on a support frame, and the drying bin is rotated on the support frame by a first driving device. A compressor, a filter, an electronic expansion valve, an evaporator and a compressor are arranged outside the drying bin; the compressor, the heat exchanger, the filter, the electronic expansion valve, the evaporator and the compressor are connected at one time by a pipeline.

[0007] The drying chamber rotates around the heat exchanger along an axis.

[0008] Electric valves are arranged between the feed port and the drying bin, between the discharge port and the drying bin, and between the air inlet duct and the air exhaust duct.

[0009] A temperature and humidity sensor is arranged in the drying chamber, and a controller is arranged on the outer wall of the drying chamber. The controller is electrically connected to the temperature and humidity sensor and the electric valve respectively.

[0010] The contact heat pump dryer provided by the present invention also has the following technical features:

[0011] Furthermore, the heat exchanger comprises a heat exchange tube, on which fins 2-2 are evenly arranged, and an angle between the fin and the heat exchange tube is 30-60 degrees.

[0012] Furthermore, the spacing between the fins on adjacent heat exchange pipes is greater than the size of a single unit of the object to be dried.

[0013] Furthermore, both sides of the middle part of the drying bin extend outward to form a rotating shaft, and the rotating shaft is rotatably connected to the support frame through bearings. The pipes between the compressor and the heat exchanger and the pipes between the heat exchanger and the filter all pass through the center of the rotating shaft, and the pipes between the compressor and the heat exchanger and the pipes between the heat exchanger and the filter are rotatably connected to the rotating shaft.

[0014] Furthermore, the first driving device includes a first motor, which is mounted on a support frame. A driving wheel is connected to the rotating shaft of the first motor. The driving wheel is connected to a driven wheel via a belt, and the driven wheel is mounted on an air outlet duct on the outer wall of the drying chamber.

[0015] Furthermore, one end of the exhaust duct extends into the drying bin, a first suction fan is provided in the exhaust duct, the exhaust duct and the drying bin are connected at the junction through a bearing, a second driving device is provided on the outer wall of the drying bin below the exhaust duct, the second driving device drives the exhaust duct to rotate, and the speed of the second driving device.

[0016] Furthermore, a plurality of exhaust holes are provided on one side of the exhaust pipe, and the exhaust ports correspond to the heat exchanger.

[0017] Furthermore, a second suction fan is provided on one side of the evaporator, the second suction fan is connected to the evaporator, the exhaust duct extends outward along the outer wall of the drying bin and is connected to the lower wall of the air inlet duct, and a dehumidification duct is provided on the exhaust duct, and the dehumidification duct corresponds to the air inlet of the second fan.

[0018] The present invention has the following beneficial effects:

[0019] 1. The invention uses a drying chamber, a heat exchanger, a compressor, a filter, an electronic expansion valve, and an evaporator to realize the use of carbon dioxide as a working fluid to dry materials. This is green, environmentally friendly, and pollution-free, and prevents pollution caused by leakage of traditional refrigeration working fluids.

[0020] 2. The present invention realizes the reuse of heat energy through the temperature sensor, the three-way valve, the first suction fan and the second suction fan. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The present invention is a schematic structural diagram of a contact heat pump drying machine.

[0022] Figure 2The present invention is a schematic diagram of the drying chamber structure in a contact heat pump dryer. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] like Figure 1-2 As shown, a contact heat pump dryer comprises a drying bin 1, wherein a heat exchanger 2 is arranged in the drying bin 1, a material feed port 3 is arranged on the end face of the drying bin 1, a material discharge port 4 is arranged on the bottom face of the drying bin 1, an air inlet duct 5 and an air exhaust duct 6 are respectively arranged on the side walls of the drying bin 1, and a first suction fan 10 is arranged in the exhaust duct 6.

[0025] The drying bin 1 is rotatably arranged on the support frame 11, and the drying bin 1 is rotated on the support frame 11 by a first driving device. Both sides of the middle part of the drying bin extend outward to form a rotating shaft, and the rotating shaft is rotatably connected to the support frame through bearings. The pipeline between the compressor and the heat exchanger and the pipeline between the heat exchanger and the filter all pass through the center of the rotating shaft, and the pipeline between the compressor and the heat exchanger and the pipeline between the heat exchanger and the filter are rotatably connected to the rotating shaft.

[0026] A compressor, a filter, an electronic expansion valve, an evaporator and a compressor are arranged outside the drying chamber; the compressor, the heat exchanger, the filter, the electronic expansion valve, the evaporator and the compressor are connected at one time through a pipeline.

[0027] The drying chamber rotates around the heat exchanger along an axis.

[0028] Electric valves are provided between the feed port 3 and the drying bin 1 , between the discharge port and the drying bin 1 , and between the air inlet duct 5 and the air exhaust duct 6 .

[0029] A temperature and humidity sensor 25 is disposed in the drying chamber 1 , and a controller 26 is disposed on the outer wall of the drying chamber 1 . The controller 26 is electrically connected to the temperature and humidity sensor 25 and the electric valve respectively.

[0030] The heating process of the present invention is as follows: the low-temperature and low-pressure subcritical carbon dioxide gas is compressed into high-temperature and high-pressure transcritical carbon dioxide gas through the compressor 12, and then enters the heat exchanger 2 through the pipeline, and the material is heated and heated by the heat exchanger 2, and the moisture in the material is evaporated by the heat, and then the cooled carbon dioxide gas enters the filter 13 through the pipeline, and then the carbon dioxide flowing out of the filter 13 enters the electronic expansion valve 14 for throttling expansion, and the carbon dioxide in the electronic expansion valve 14 enters the evaporator 15, and the carbon dioxide in the evaporator 15 enters the compressor 12 for re-compression, and circulates again. At the same time, the first driving device drives the drying bin 1 to rotate, and the heat exchanger 2 does not move, so that the material in the drying bin 1 is heated evenly.

[0031] Monitoring: The temperature and humidity in the drying box are detected by the temperature and humidity sensor 25, and then the temperature signal and humidity signal are transmitted to the controller 26. The controller 26 controls the opening of the electric valve on the air inlet duct 5 and the first suction fan 10 according to the set limit value.

[0032] Dehumidification: When the temperature and humidity sensor 25 detects that the humidity is higher than the set value of 60%~75% or higher than 70 degrees, the controller 26 controls the electric valve on the exhaust duct 6 to open, the electric valve on the air inlet duct 5 to open, and the first suction fan 10 to open for dehumidification, so that the moisture in the drying chamber 1 is circulated and exchanged with the air.

[0033] The heat exchanger 2 includes a heat exchange tube 2-1, on which fins 2-2 are evenly arranged, and the angle between the fins 2-2 and the heat exchange tube 2-1 is 30-60 degrees.

[0034] When the high-temperature and high-pressure transcritical carbon dioxide gas in the compressor 12 enters the heat exchange tube 2-1 through the air inlet pipe, the heat of the carbon dioxide is quickly dissipated through the fins 2-2 to heat the drying chamber 1. The angle between the fins 2-2 and the heat exchange tube 2-1 is 30-60 degrees, which allows the material to slide on the fins 2-2 and the material is heated more evenly.

[0035] The distance between the fins 2-2 on the adjacent heat exchange tubes 2-1 is larger than the size of the dried object, so as to prevent the material from being stuck between the fins 2-2.

[0036] The first driving device includes a first motor 16, which is mounted on the support frame 11. A first driving wheel 17 is connected to the rotating shaft of the first motor 16. The driving wheel is connected to a first driven wheel 18 via a belt. The first driven wheel 18 is mounted on the air outlet pipe 8.

[0037] The first motor 16 rotates to drive the first driving wheel 17 to rotate, and the first driving wheel 17 drives the first driven wheel 18 to rotate through a belt, and the first driven wheel 18 drives the drying bin 1 to rotate on the support frame 11. The rotation of the drying bin 1 can make the material in the drying bin 1 evenly heated and evenly dried.

[0038] One end of the exhaust duct 6 extends into the drying bin 1, and the exhaust duct 6 is connected to the drying bin 1 at its junction through a bearing. A second driving device is provided on the outer wall of the drying bin 1 below the exhaust duct 6, and the second driving device drives the exhaust duct 6 to rotate. The second driving device includes a second motor 19, on which a second driving wheel 20 is fixedly provided, and the second driving wheel 20 is connected to a second driven wheel 21 through a belt, and the second driven wheel 21 is installed on the exhaust duct 6. A plurality of exhaust holes 22 are provided on one side of the exhaust duct 6, and the exhaust holes 22 correspond to the heat exchanger 2.

[0039] The second motor 19 rotates at the same speed as the first motor 16 to ensure that the exhaust holes 22 on the air outlet pipe are always facing downward during the rotation process, thereby preventing the exhaust holes 22 from being blocked by materials during the rotation of the drying bin 1.

[0040] A second suction fan 23 is provided on one side of the evaporator 15, and the second suction fan 23 is connected to the evaporator 15. The exhaust duct 6 extends outward along the outer wall of the drying chamber 1 and is connected to the lower side wall of the air inlet duct 5. A dehumidification duct 27 is provided on the exhaust duct 6, and the dehumidification duct 27 corresponds to the air inlet of the second suction fan 23.

[0041] The drying process is generally divided into two stages.

[0042] The first stage is the heating stage, at this time, the rotation of the drying bin 1 and the start of the first motor 16 are intermittently operated. When the drying bin 1 rotates to ensure that the material is more evenly distributed, it stops rotating and returns to the starting angle. At this time, the first suction fan 10 is turned on, and the electric valve on the exhaust duct 6 and the electric valve on the air inlet duct 5 are opened to form a circulation of the air inlet duct 5, the heat exchanger, the exhaust duct 6, and the air inlet duct 5, and the circulation is maintained for 5-10 minutes. The above process is repeated according to the humidity and temperature of the material in the drying bin 1.

[0043] The second stage is the dehumidification heat recovery stage. When the humidity of the air in the drying chamber 1 is higher than 60%~75% or the temperature is higher than 70 degrees, the drying chamber 1 stops rotating, the electric valve on the air inlet duct 5, the first suction fan 10, and the second suction fan 23 are opened, and the high-temperature and high-humidity air in the drying chamber 1 enters the exhaust duct 6 through the exhaust hole 22, and enters the evaporator 15 through the dehumidification duct 27, and most of the heat is recovered and discharged into the atmosphere. The air in the atmosphere enters the drying chamber 1 from the air inlet duct 5. When the humidity in the drying chamber 1 is consistent with the atmospheric humidity, the dehumidification is completed.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A drying method of a contact heat pump dryer, comprising a drying chamber, characterized in that: The drying bin is provided with a heat exchanger, the end surface of the drying bin is provided with a feed port, the bottom surface of the drying bin is provided with a discharge port, the side walls of the drying bin are provided with an air inlet duct and an air exhaust duct, and the exhaust duct is provided with a first suction fan; The drying bin is rotatably arranged on the support frame, and the drying bin is rotated on the support frame by a first driving device, and a compressor, a filter, an electronic expansion valve, an evaporator and a compressor are arranged outside the drying bin; the compressor, the heat exchanger, the filter, the electronic expansion valve, the evaporator and the compressor are connected at one time by a pipeline; The drying chamber rotates around the heat exchanger along the axis; Electric valves are provided between the feed port and the drying bin, between the discharge port and the drying bin, and in the air inlet duct; A temperature and humidity sensor is provided in the drying chamber, and a controller is provided on the outer wall of the drying chamber, and the controller is electrically connected to the temperature and humidity sensor, the electric valve, the first suction fan, and the first driving device respectively; The heat exchanger comprises a heat exchange tube, on which fins are evenly arranged, and the angle between the fins and the heat exchange tube is 30-60 degrees; The distance between the fins on the adjacent heat exchange pipes is greater than the size of the individual pieces of the dried object; The two sides of the middle part of the drying bin extend outward to form a rotating shaft, the rotating shaft is rotatably connected to the support frame through bearings, the pipeline between the compressor and the heat exchanger and the pipeline between the heat exchanger and the filter pass through the center of the rotating shaft, and the pipeline between the compressor and the heat exchanger and the pipeline between the heat exchanger and the filter are rotatably connected to the rotating shaft; The first driving device comprises a first motor, the first motor is mounted on a support frame, a driving wheel is connected to the rotating shaft of the first motor, the driving wheel is connected to a driven wheel via a belt, and the driven wheel is mounted on an air outlet pipe on the outer wall of the drying chamber; One end of the exhaust duct extends into the drying chamber, the exhaust duct and the drying chamber are connected at their junction by a bearing, a second driving device is provided on the outer wall of the drying chamber below the exhaust duct, the second driving device drives the exhaust duct to rotate, and the rotation speed of the second driving device is the same as that of the first driving device; A plurality of exhaust holes are provided on one side of the exhaust duct, and the exhaust holes correspond to the heat exchanger; A second suction fan is provided on one side of the evaporator, the second suction fan is connected to the evaporator, the exhaust duct extends outward along the outer wall of the drying chamber and is connected to the lower side wall of the air inlet duct, and a dehumidification duct is provided on the exhaust duct, and the dehumidification duct corresponds to the air inlet of the second fan; The drying process is divided into two stages; The first stage is the heating stage. At this time, the rotation of the drying bin and the start of the first motor are intermittent. When the drying bin rotates to ensure that the material is more evenly distributed, it stops rotating and returns to the starting angle. At this time, the first suction fan is turned on, and the electric valve on the exhaust duct and the electric valve on the air inlet duct are opened to form a cycle of the air inlet duct, heat exchanger, exhaust duct, and air inlet duct. The cycle is maintained for 5-10 minutes. The above process is repeated according to the humidity and temperature of the material in the drying bin. The second stage is the dehumidification heat recovery stage. When the humidity of the air in the drying chamber is higher than 60%~75% or the temperature is higher than 70 degrees, the drying chamber stops rotating, the electric valve, the first suction fan and the second suction fan on the air inlet duct are opened, and the high-temperature and high-humidity air in the drying chamber enters the exhaust duct through the exhaust hole, enters the evaporator through the dehumidification duct, recovers most of the heat, and is discharged into the atmosphere; the air in the atmosphere enters the drying chamber from the air inlet duct, and when the humidity in the drying chamber is consistent with the atmospheric humidity, the dehumidification is completed.

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