Ice persimmon closed-loop heat pump dryer and control method thereof

Abstract

The invention discloses an ice persimmon closed-loop heat pump dryer which comprises a drying chamber and a heat exchange system, and the drying chamber is provided with an air valve and a fan; the heat exchange system comprises a compressor, a condenser set, an electronic expansion valve and an evaporator which are sequentially connected and form a refrigerant circulation loop. The drying chamber has a high-temperature mode and a low-temperature mode, when the drying chamber is in the high-temperature mode, the air valve is closed, and when the drying chamber is in the low-temperature mode, the air valve is opened. The indoor condenser and the outdoor condenser are arranged, so that the drying chamber can be flexibly switched between a high-temperature mode and a low-temperature mode, and the alternate operation mode not only can quickly and uniformly remove moisture in the persimmons, but also effectively reduces the tannin content in the persimmons. An air valve is arranged in the drying chamber and can change the flow direction of air in the drying chamber according to the working mode. Air flows through the heat regenerator twice and is heated / cooled, and the humidity is rapidly reduced in the process.

Description

Technical Field

[0001] The invention relates to the technical field of dryers, and in particular to an ice-persimmon closed-loop heat pump dryer. Background Art

[0002] Persimmon is one of the main fruits in my country. Fresh persimmons are rich in cellulose, calcium, vitamin C, carotene, sugar, protein, and trace elements such as iron and iodine, and are deeply loved by consumers. However, the picking period of fresh persimmons is short, and they are easy to soften at room temperature after picking, which is not convenient for storage and transportation. Therefore, growers usually process persimmons into persimmon cakes to extend the shelf life and shelf time. There are currently two methods for processing persimmon cakes: natural drying and artificial drying. The natural drying method has the disadvantages of high labor intensity and poor hygiene due to the need for manual drying. The artificial drying method using heat pump drying can effectively improve the hygiene and production efficiency of persimmon cakes.

[0003] Ice persimmon is a new type of persimmon processing method. Ice persimmon has the characteristics of good taste, less astringency and long shelf life. Ice persimmon has high technical content and novel taste. It is a deep processing method of persimmon.

[0004] In traditional heat pump drying equipment, heat pump dryers can only provide dehumidification or drying effects, and ventilation or natural cooling can only be used to cool the drying room. In the production of ice persimmons, in order to eliminate the tannins in the persimmons, the persimmons need to be baked in a cycle of high temperature baking and low temperature baking for many times, but traditional heat pump dryers cannot quickly provide a low temperature baking environment. Therefore, it is necessary to develop a targeted ice persimmon processing equipment that can take into account both high temperature baking and low temperature baking. Summary of the invention

[0005] Therefore, in order to solve the above problems, the object of the present invention is to provide an ice persimmon closed-loop heat pump dryer, comprising:

[0006] A drying room, wherein the drying room is provided with an air valve and a fan;

[0007] A heat exchange system, the heat exchange system comprising a compressor, a condenser group, an electronic expansion valve, and an evaporator which are sequentially connected to form a refrigerant circulation loop, the condenser group comprising an indoor condenser and an outdoor condenser, and the indoor condenser is arranged in a drying room;

[0008] The drying room has a high temperature mode and a low temperature mode. When the drying room is in the high temperature mode, the air valve is closed, and the fan blows air to form a circulating heating air duct. The heating air duct path is: indoor condenser, regenerator, evaporator, regenerator, indoor condenser. When the drying room is in the low temperature mode, the air valve is opened, and the fan blows air to form a circulating cooling air duct. The cooling air duct path is: indoor condenser, air valve, evaporator, regenerator, indoor condenser.

[0009] Preferably, the air valve is arranged in the middle of the drying room, the regenerator, the fan, the evaporator and the indoor condenser form a set of indoor kits, and the two sets of indoor kits are symmetrically arranged in the drying room along the air valve.

[0010] Preferably, the compressor is connected to the indoor condenser and the outdoor condenser via a three-way valve.

[0011] A control method for the above-mentioned ice persimmon closed-loop heat pump dryer: after the ice persimmons are placed in the drying chamber, the drying chamber is first adjusted to a high-temperature mode to bake the ice persimmons for x hours, and then adjusted to a low-temperature mode to treat the ice persimmons at a low temperature for x hours, and the high-temperature mode and the low-temperature mode are adjusted alternately in a cycle until the ice persimmons are completely dried.

[0012] Preferably, x=0.5.

[0013] Preferably, the drying process is completed after the high temperature mode / low temperature mode of the drying chamber is adjusted alternately 16 times in a cycle.

[0014] Preferably, a high temperature threshold t1, a low temperature threshold t2, and a humidity threshold φ are set. o , a temperature sensor and a humidity sensor are set in the drying room. When the drying room is in high temperature mode, the temperature in the drying room is higher than t3 and the humidity is lower than φ o When t2 is on, the heat exchange system is on standby; when the drying chamber is in low temperature mode and the temperature inside the drying chamber is lower than t2, the heat exchange system is on standby.

[0015] The beneficial effects of the present invention are:

[0016] The indoor condenser and outdoor condenser provided in the present invention enable the drying chamber to flexibly switch between a high temperature mode and a low temperature mode. This alternating operation mode can not only quickly and evenly remove moisture from the persimmon fruit, but also effectively reduce the tannin content in the persimmon fruit.

[0017] The drying chamber is equipped with a built-in air valve, which can change the air flow direction in the drying chamber according to the working mode. The air flows through the regenerator twice and heats up / cools down, which quickly reduces the humidity in the process. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 is a schematic diagram of the present invention in a heating and drying mode;

[0020] Figure 2It is a schematic diagram of the present invention in a cooling and temperature reduction mode;

[0021] Figure 3 It is a schematic flow chart of the control method of the present invention;

[0022] Explanation of the figure numbers: 1. Compressor; 2. Three-way valve; 3. Outdoor condenser; 4. Indoor condenser; 5. Electronic expansion valve; 6. Evaporator; 7. Regenerator; 8. Air valve.

[0023] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0025] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0026] Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0027] Embodiment 1:

[0028] Figure 1-Figure 3 The present invention shows an ice persimmon closed-loop heat pump dryer, which includes a drying chamber and a heat exchange system. An air valve 8 and a fan are provided in the drying chamber. The fan blows air to form a circulating air duct in the drying chamber. The opening / closing of the air valve 8 can change the flow direction of the air duct. The heat exchange system includes a compressor 1, a condenser group, an electronic expansion valve 5, and an evaporator 6 connected in sequence end to end, and forms a circulation loop for the refrigerant to flow. The condenser group includes an indoor condenser 4 and an outdoor condenser 3. The indoor condenser 4 is arranged in the drying chamber.

[0029] The drying room has two operating modes, namely high temperature mode and low temperature mode. When the drying room is in high temperature mode, the air valve 8 is closed, and the fan blows air to form a circulating heating air duct. The heating air duct path is: indoor condenser 4, regenerator 7, evaporator 6, regenerator 7, indoor condenser 4, and the refrigerant circulation loop is: compressor 1, indoor refrigerator, electronic expansion valve 5, evaporator 6; when the drying room is in low temperature mode, the air valve 8 is opened, and the fan blows air to form a circulating cooling air duct. The cooling air duct path is: indoor condenser 4, air valve 8, evaporator 6, regenerator 7, indoor condenser 4, and the refrigerant circulation loop is: compressor 1, outdoor refrigerator, electronic expansion valve 5, evaporator 6.

[0030] The fan is arranged near the indoor condenser 4. When the drying chamber is in the high temperature mode, the air valve 8 is closed, and the indoor circulating air is blown out from the indoor condenser 4 to form the drying chamber return air. The drying chamber return air passes through the regenerator 7 for preliminary cooling, and then passes to the evaporator 6. The evaporator 6 cools and dehumidifies it and then flows back to the regenerator 7 to form the low-temperature return air. At this time, the low-temperature return air exchanges heat with the drying chamber return air just blown out from the drying chamber. The low-temperature return air is heated and then flows to the indoor condenser 4. It is further heated and the humidity is reduced at the indoor condenser 4, and finally blown out again from the fan to form the next circulating air; when the drying chamber is in the low temperature mode, the air valve 8 is opened, and the indoor circulating air is blown out from the indoor condenser 4 to form the drying chamber return air. The drying chamber return air passes through the opened air valve 8 directly to the evaporator 6, and then flows through the regenerator 7 and finally returns to the indoor condenser 4. It is blown out by the fan to form the next circulating air. When the refrigerant flows through the evaporator 6, it absorbs the heat of the drying chamber return air and then dissipates the heat at the outdoor condenser 3.

[0031] In this embodiment, two drying chambers are combined together, and an air valve 8 is arranged in the middle of the two drying chambers. Two sets of heat exchange systems are configured accordingly, which are symmetrically arranged along the air valve 8. Reasonable arrangement of the position of the air valve 8 can save the number of air valves 8 used and reduce the manufacturing cost of the equipment.

[0032] In the heat exchange system, the compressor 1 is connected to the indoor condenser 4 and the outdoor condenser 3 respectively through a three-way valve 2.

[0033] The heat exchange system and the air valve 8 and fan in the drying room are controlled by the following methods:

[0034] First peel and wash the persimmons, then put them into the drying room, adjust the drying room to high temperature mode, bake the frozen persimmons for x hours in high temperature mode, and then adjust to low temperature mode, bake the frozen persimmons at low temperature for x hours; alternately switch between high temperature mode and low temperature mode until the humidity of the frozen persimmons reaches the requirement and the drying process is completed.

[0035] In this embodiment, after multiple experimental calculations, it is found that when the number of cycles is 16 times, and x=0.5, the high temperature mode setting temperature is 45°C, and the low temperature mode setting temperature is 18°C, the ice persimmon drying effect is better, and the total drying time is 8 hours. The following example:

[0036] Set the time T, set 16 time nodes T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16 in sequence. The interval between two time nodes is 0.5 hours, and the high temperature mode time period of the drying room is:

[0037] [0~T1,T2~T3,T4~T5,T6~T7,T8~T9,T10~T11,T12~T13,T14~T15];

[0038] The low temperature mode time periods are:

[0039] [T1~T2, T3~T4, T5~T6, T7~T8, T9~T10, T11~T12, T13~T14, T15~T16];

[0040] After completing the operations in the above time period, the air valve 8, the fan and the heat exchange system are stopped.

[0041] A high temperature threshold t1, a low temperature threshold t2, and a humidity threshold φo are also set. A temperature sensor and a humidity sensor are set in the drying room. When the drying room is in high temperature mode, the temperature in the drying room is higher than t1 and the humidity is lower than φo, the heat exchange system is on standby. When the drying room is in low temperature mode and the temperature in the drying room is lower than t2, the heat exchange system is on standby. The heat exchange system is set to standby when the humidity reaches the standard to save resources.

[0042] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. An ice persimmon closed-loop heat pump dryer, characterized in that: include: A drying room, wherein the drying room is provided with an air valve and a fan; A heat exchange system, the heat exchange system comprising a compressor, a condenser group, an electronic expansion valve, and an evaporator which are sequentially connected to form a refrigerant circulation loop, the condenser group comprising an indoor condenser and an outdoor condenser, and the indoor condenser is arranged in a drying room; The drying chamber has a high temperature mode and a low temperature mode. When the drying chamber is in the high temperature mode, the air valve is closed, and when the drying chamber is in the low temperature mode, the air valve is opened.

2. The ice persimmon closed-loop heat pump dryer according to claim 1, characterized in that: The air valve is arranged in the middle of the drying room, and the heat regenerator, the fan, the evaporator and the indoor condenser form a set of indoor kits, and the two sets of indoor kits are symmetrically arranged in the drying room along the air valve.

3. The ice persimmon closed-loop heat pump dryer according to claim 1, characterized in that: The compressor is connected to the indoor condenser and the outdoor condenser through a three-way valve.

4. A control method for the ice persimmon closed-loop heat pump dryer according to any one of claims 1 to 3, characterized in that: Put the frozen persimmons into the drying room. First adjust the drying room to high temperature mode and bake the frozen persimmons for x hours. Then adjust it to low temperature mode and treat the frozen persimmons at low temperature for x hours. Alternately adjust the high temperature mode and the low temperature mode until the frozen persimmons are dried.

5. The control method of the ice persimmon closed-loop heat pump dryer according to claim 4 is characterized in that: x＝0.5。 6. The control method of the ice persimmon closed-loop heat pump dryer according to claim 4 is characterized in that: The drying process is completed after the high temperature mode / low temperature mode of the drying chamber is adjusted alternately 16 times.

7. The control method of the ice persimmon closed-loop heat pump dryer according to claim 4 is characterized in that: Set the high temperature threshold t1, low temperature threshold t2, and humidity threshold φ o , a temperature sensor and a humidity sensor are set in the drying room. When the drying room is in high temperature mode, the temperature in the drying room is higher than t3 and the humidity is lower than φ o When t2 is on, the heat exchange system is on standby; when the drying chamber is in low temperature mode and the temperature inside the drying chamber is lower than t2, the heat exchange system is on standby.

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