CN108534477B - Drying system - Google Patents

Abstract

The invention discloses a drying system, comprising a heat pump unit and a drying chamber, the heat pump unit is provided with a cold air pipe for introducing cold air and an air supply pipe for exporting hot air, and one side wall of the drying chamber is covered with There is an air supply port, the other opposite side wall of the drying chamber is covered with air outlets, the air supply pipe is connected with the air supply port, and the air outlet is connected with a first air exhaust pipe and a second air outlet. An exhaust pipe, the first exhaust pipe is in communication with the outside, and the second exhaust pipe is in communication with the heat pump unit. Through its structural design, the drying system can easily realize the synchronous drying of materials in different areas of the drying room, greatly optimize the drying quality of materials, and reduce the energy consumption and time of system operation.

Description

a drying system

technical field

The present invention relates to the field of drying equipment, more particularly, to a drying system.

Background technique

Drying generally refers to various operations that remove moisture or other moisture from wet materials. For example: in daily life, the moist materials are exposed to sunlight to remove moisture; in industry, silica gel, lime, concentrated sulfuric acid, etc. are used to remove moisture in air, industrial gases or organic liquids; chemical production relies on heat and mass transfer, using hot air , flue gas and infrared heating wet solid material, so that the water or solvent contained in it is evaporated and removed. The purpose of drying is to make the material easy to store, transport and use, or to meet the needs of further processing. For example, grains and vegetables can be stored for a long time after drying; synthetic resin can prevent air bubbles or moiré in plastic products after drying; paper is easy to use and store after drying. Due to the many benefits of dried products, drying is widely used in various sectors such as chemical industry, food, light industry, textile, coal, agricultural and forestry product processing and building materials, and various drying devices have emerged as the times require.

At present, heat pump drying equipment is a commonly used drying device. In the specific implementation process, the heat pump drying equipment uses the heat pump to generate heat, and then uses the heat to circulate and heat the air, and then uses the hot air formed after heating to bake the moisture in the material to be dried in the drying room and transfer it to water vapor. Then the water vapor is mixed with the air and discharged together as moist air, so as to realize the dehumidification and drying of the material. In the actual operation process, due to the limitations of the existing heat pump drying equipment structure design, the inlet and outlet of the air circulation into and out of the drying chamber are usually a single square or round port. The room shrinks and then discharges, so that the resistance of the air entering and leaving the drying room is very large, resulting in uneven air speed and air volume in the drying room, especially the four corners of the drying room are often dead corners for ventilation, resulting in the drying progress of materials in different areas of the drying room. Inconsistency greatly affects the drying quality of materials and increases the energy consumption and time of system operation.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a drying system, which can easily realize the synchronous drying of materials in different areas in the drying room through its structural design, greatly optimize the drying quality of materials, and reduce the energy consumption and time of system operation. .

A drying system includes a heat pump unit and a drying chamber, the heat pump unit is provided with a cold air pipe for introducing cold air and an air supply pipe for exporting hot air, and the side wall of one side of the drying chamber is fully covered with air supply ports, The other opposite side wall of the drying chamber is covered with air outlets, the air supply pipe is connected with the air supply port, and the air outlet is connected with a first air exhaust pipe and a second air exhaust pipe, The first exhaust pipe communicates with the outside, and the second exhaust pipe communicates with the heat pump unit.

Preferably, the air supply ports are uniformly distributed on the left side wall of the drying chamber from top to bottom, and the air outlets are uniformly distributed on the right side wall of the drying chamber from top to bottom.

Preferably, an air supply chamber is provided between the air supply pipe and the air supply port, and a return air chamber is provided between the air outlet and both the first air exhaust pipe and the second air exhaust pipe.

Preferably, the air supply ports are uniformly distributed on the upper sidewall of the drying chamber from left to right, and the air outlets are uniformly distributed on the lower sidewall of the drying chamber from left to right.

Preferably, the cold air pipe is inserted through the first air exhaust pipe, and the cold air pipe is covered with a total heat exchanger, and the total heat exchanger is used for transferring the heat in the first air exhaust pipe to the the inner cavity of the cold air pipe.

Preferably, the heat pump unit includes a case with a ventilation valve inside, and the upper side wall of the case is sequentially provided with a fresh air outlet with a fresh air valve and communicated with the outside from left to right, with a blower and communicated with the air supply duct. The air supply port, the heat recovery air port communicated with the cold air duct and the second air exhaust duct, the air inlet that is installed with the fresh air temperature sensor and the fresh air humidity sensor and communicated with the outside, the right side wall of the chassis is provided with External cold and heat surface cooler and external fan, the left side wall of the case is provided with a total air return port that communicates with the second air exhaust pipe; the inner cavity of the case is provided with a pipe valve assembly, the pipe valve assembly The compressor is connected below, the left side of the pipe valve assembly is connected with a dehumidification surface cooler and an inner cooling heat surface cooler; the right side of the pipe valve assembly is connected with the outer cold heat surface cooler.

Preferably, a primary air return port and a secondary air return port are provided in the total air return port, a primary air return air adjustment plate is provided in the primary air return air port, and a secondary air return air adjustment plate is provided in the secondary air return port.

Preferably, the pipe valve assembly includes a front four-way valve, a rear four-way valve, an external cooling and heating solenoid valve, a dehumidification solenoid valve, a rear cooling solenoid valve, an expansion valve, a first one-way valve, a second one-way valve, a third one-way valve, and a third one-way valve. Three one-way valve, fourth one-way valve and fifth one-way valve, wherein, the compressor discharge port is connected to the front four-way valve port D, and the front four-way valve port E is connected to the rear four-way valve. The through valve port D is connected, the front four-way valve port C is connected with one end of the inner cooling hot surface cooler, the front four-way valve port S and the rear four-way valve port S are connected with the compressor return port Connected in parallel, the rear four-way valve port E is connected to one end of the dehumidification surface cooler, the rear four-way valve port C is connected to one end of the outer cooling and heating surface cooler, and the inner cooling and heating surface cooler is another. One end, the inlet of the fourth check valve and the outlet of the fifth check valve are connected in parallel, and the other end of the external cooling and heating surface cooler, the outlet of the second check valve and the inlet of the third check valve are connected in parallel. connected in parallel, the other end of the dehumidification surface cooler is connected to the outlet of the first check valve, the inlet of the first check valve is connected to one end of the dehumidification solenoid valve, and the inlet of the second check valve is connected to the external cooler One end of the thermal solenoid valve is connected, the outlet of the third check valve and the outlet of the fourth check valve are connected in parallel with the inlet of the expansion valve, and the inlet of the fifth check valve is connected with one end of the after-cooling solenoid valve, The other end of the external cooling and heating solenoid valve, the other end of the dehumidification solenoid valve, and the other end of the after-cooling solenoid valve are connected in parallel with the expansion valve outlet.

Preferably, the heat pump unit is provided with a ventilation drying mode, a combined drying mode and an air conditioning refrigeration mode, wherein:

The ventilation and drying mode includes the following steps: ① ventilation and drying, ② shutdown;

The combined drying mode includes the following steps: ① ventilation drying, ② shutdown switching, ③ return air heating and humid air discharge, ④ return air heating, ⑤ return air heating and return air cooling and humid air discharge, ⑥ return air heating and Return air cooling, ⑦ Return air heating and return air cooling and wet air discharge, ⑧ Return air heating and return air cooling, ⑨ Shutdown;

The air-conditioning cooling mode includes the following steps: ① air cooling, ② initial cooling, ③ post cooling, and ④ standby.

The beneficial effects of the present invention are: when the drying system provided by the present invention is used, if the air moisture in the drying chamber is high, ventilation and drying are performed first, that is, when the moisture content of the material is high and the moisture on the surface of the material evaporates quickly, the ventilation is performed first. Dry, ventilate and dry to a certain extent, and then use the heat pump unit to heat and dry the circulating return air; if the air moisture in the drying room is not high, directly use the heat pump unit to heat and dry the circulating return air. Ingenious, when drying, it can effectively achieve synchronous and effective drying of materials in each area of the entire drying room; in addition, during the operation of the heat pump unit, the water in the materials is evaporated and mixed with air by heating, and then heated by return air and humidified. Air discharge drying, or simultaneous return air heating and refrigeration drying and humid air discharge drying can maximize the dehumidification capacity and heat utilization of the system provided by the present invention, so that the material can obtain higher dryness.

Description of drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only It is an embodiment of the present invention. For those of ordinary skill in the art, other drawings can also be obtained according to the provided drawings without creative work.

1 is a schematic diagram of the overall structure of the drying system disclosed in Embodiment 1 of the present invention;

2 is a schematic structural diagram of the heat pump unit disclosed in Embodiment 1 of the present invention;

3 is a schematic structural diagram of the air supply chamber disclosed in Embodiment 1 of the present invention;

4 is a schematic structural diagram of a return air chamber disclosed in Embodiment 1 of the present invention;

5 is a schematic diagram of the connection of the pipe valve assembly under the return air heating state disclosed in Embodiment 2 of the present invention;

6 is a schematic diagram of the connection of the pipe valve assembly under the state of return air heating and dehumidification disclosed in Embodiment 2 of the present invention;

7 is a schematic diagram of the connection of the pipe valve assembly under the high temperature return air refrigeration state disclosed in Embodiment 2 of the present invention;

8 is a schematic diagram of the connection of the pipe valve assembly under the low temperature refrigeration state of the return air disclosed in Embodiment 2 of the present invention;

FIG. 9 is a schematic diagram of the overall structure of the drying system disclosed in Embodiment 3 of the present invention.

Detailed ways

In order to make those skilled in the art better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described The embodiments are only a part of the embodiments of the present application, but not all of the embodiments.

Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the scope of protection of the present application.

In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", etc. is based on the orientation or positional relationship shown in the accompanying drawings, only for the purpose of It is convenient to describe the present invention and to simplify the description, rather than indicating or implying that the device or element referred to must have a particular orientation, be constructed and operate in a particular orientation, and therefore should not be construed as limiting the invention.

Embodiment 1:

Referring to FIGS. 1 to 4, FIGS. 1 to 4 provide specific embodiments of a drying system of the present invention, wherein, FIG. 1 is a schematic diagram of the overall structure of the drying system disclosed in Embodiment 1 of the present invention; FIG. 2 is the present invention Schematic diagram of the structure of the heat pump unit disclosed in Embodiment 1; FIG. 3 is a schematic diagram of the structure of the air supply chamber disclosed in Embodiment 1 of the present invention; FIG. 4 is a schematic diagram of the structure of the air return chamber disclosed in Embodiment 1 of the present invention.

As shown in Figures 1 to 4, the drying system provided by the present invention can realize synchronous drying of materials in different areas in the drying room, greatly optimize the drying quality of materials, and reduce the energy consumption and time of system operation. The drying system includes a heat pump unit 1, a drying chamber 2 with an air supply port 201 and an air outlet 202, a cold air duct 3, an air supply duct 4, a first exhaust duct 5, a second exhaust duct 6, an air supply chamber 7, and a return air duct 4. Air chamber 8, total heat exchanger 9. The arrows in the drawings indicate the flow direction of the air.

In this solution, the drying system includes a heat pump unit 1, and the heat pump unit 1 is used to provide power output for the drying of the system, including providing the power required for air flow in the drying system and the heating and cooling required for material drying.

The drying chamber 2 is used to provide drying space for materials, and the specific structure and size of the drying chamber 2 are selected and designed according to actual needs. In this scheme, the cuboid-shaped drying chamber 2 is selected, and the heat pump unit 1 is connected to the right side of the drying chamber 2.

The heat pump unit 1 is provided with a cold air pipe 3 for introducing cold air and an air supply pipe 4 for exporting hot air; The air outlet 202 is arranged, the air supply pipe 4 is connected with the air supply port 201, the air outlet 202 is connected with the first air exhaust pipe 5 and the second air exhaust pipe 6, and the first air exhaust pipe 5 is connected with the outside, The second exhaust pipe 6 is connected to the heat pump unit 1 .

In this solution, the air supply ports 201 are uniformly distributed on the left side wall of the drying chamber 2 from top to bottom, and the air outlets 202 are uniformly distributed on the right side wall of the drying chamber 2 from top to bottom. An air supply chamber 7 is provided between the air supply pipe 4 and the air supply port 201 , and a return air chamber 8 is provided between the air outlet 202 and the first air exhaust pipe 5 and the second air exhaust pipe 6 . The horizontally arranged air supply chamber 7 and the horizontally arranged return air chamber 8 function as static pressure boxes. In this way, the hot air can be horizontally input into the inner cavity of the drying chamber 2 from the air supply port 201 on the left side of the drying chamber 2, and output horizontally from the air outlet 202 on the right side wall of the drying chamber 2, and the air flow area covers the interior of the drying chamber 2 from above. Down the entire height, so that the materials in the drying chamber 2 can be dried without dead ends and synchronously.

In this solution, the air supply ports 201 are uniformly distributed on the left side wall of the drying chamber 2 from top to bottom, and the air outlets 202 are uniformly distributed on the right side wall of the drying chamber 2 from top to bottom. Of course, other setting methods can also be used. For example, the widths of the air outlet 201 and the air outlet 202 increase from small to large from top to bottom. In other words, the air outlet 201 and the air outlet 202 have the same width, but the margins between adjacent air outlets 201 and the air outlet 202 increase from small to large from top to bottom. In this way, through the above-mentioned specially designed multiple horizontal slit air supply ports 201 and horizontal slit air outlets 202, the hot air sent horizontally to the drying room 2 increases from small to large and remains stable from top to bottom, so that the materials in the drying room 2 are kept stable. The obtained heat increases from small to large and remains stable from top to bottom, so as to balance the phenomenon that the hot air rises lightly and the temperature above the drying room 2 is higher than that of the bottom, and further achieves the requirement that the drying time of the upper and lower materials in the drying room 2 is basically the same.

In this scheme, in order to further facilitate the recycling of heat and avoid waste of heat directly discharged into the air, the cold air pipe 3 is inserted through the first air exhaust pipe 5, and the cold air pipe 3 is covered with a total heat exchanger 9. The heat exchanger 9 is used to transfer the heat in the first exhaust pipe 5 to the inner cavity of the cold air pipe 3 , so that the cold air in the inner cavity of the cold air pipe 3 can be preheated by using the residual heat of the air in the first exhaust pipe 5 .

In this scheme, in order to further facilitate the output and control of power, an efficient and energy-saving heat pump unit is provided. The heat pump unit 1 includes a chassis 101, a ventilation valve 102, a fresh air valve 103, a fresh air outlet 104, a blower 105, an air outlet 106, a heat recovery air outlet 107, an air inlet 108, an external cooling and heating surface cooler 109, an external fan 110, and a total return Air outlet 111 , pipe valve assembly 112 , compressor 113 , dehumidification surface cooler 114 and inner cooling heat surface cooler 115 .

The cabinet 101 is provided with a ventilation valve 102. The ventilation valve 102 is used for the on-off control of each air passage. The upper side wall of the cabinet 101 is sequentially provided with a fresh air valve 103 from left to right and a fresh air outlet 104 connected to the outside. There is a blower 105 and an air supply port 106 communicated with the air supply duct 4, a heat recovery air port 107 communicated with the cold air duct 3 and the second exhaust duct 6, and a fresh air temperature sensor C1 and a fresh air humidity sensor H1 are installed And the air inlet 108 communicates with the outside, the outer cooling and heating surface cooler 109 and the outer fan 110 are arranged on the side wall of the right side 101 of the case, and the second exhaust air is arranged on the left side wall of the case 101. The total air return port 111 that the pipe 6 communicates with.

The inner cavity of the case 101 is provided with a pipe valve assembly 112, a compressor 113 is connected below the pipe valve assembly 112, and a dehumidification surface cooler 114 and an inner cooling heat surface cooler 115 are connected to the left side of the pipe valve assembly 112; The right side of the pipe valve assembly 112 is connected to the external cooling and heating surface cooler 109 .

In order to further realize the control of the return air direction and flow rate in the heat pump unit 1, preferably, a primary return air outlet and a secondary air return air outlet are arranged in the total air return outlet 111, and a primary air return air adjustment plate is arranged in the primary air return outlet, and the two A secondary air return adjusting plate is arranged in the secondary air return port. Specifically, the primary air return port directly leads to the inner cavity of the heat pump unit 1, and the secondary air return port goes through the dehumidification surface cooler to the inner cavity of the heat pump unit 1.

In the specific implementation process, the secondary return air is first cooled and dehumidified by the dehumidification surface cooler 114, then mixed with the circulating return air of the primary return air outlet, and then heated through the internal cooling hot surface cooler 115, so the resistance of the secondary return air is greater than that of the primary return air ; Through the adjustment of the primary return air adjustment plate and the secondary return air adjustment plate, the ratio of the primary return air volume to the secondary return air volume can reach the appropriate requirements.

When cooling and dehumidifying, the secondary return air from the dehumidification surface cooler 114 should be lower than the dew point temperature, and the gaseous water in the secondary return air can be condensed to a liquid state. Therefore, the secondary return air volume should be based on the temperature difference between the dehumidification surface cooler 114 and the condensed water. More requests are made. When the moisture content of the fresh air is less than the moisture content of the return air, the blower will run, the fresh air valve will be opened, and the exhaust fan will run. When the fresh air is inhaled, it will be heated by the total heat exchanger 9 in advance and then mixed with the return air evenly. The humid air in the drying room 2 will pass through the first An exhaust pipe 5 is discharged to meet the requirements of material drying.

When the humid air is exhausted, if the fresh air volume is too small, the humid air will be exhausted too small; if the humid air exhaust is too small, the drying time of the material will be long; if the fresh air volume is too large, the humid air will be exhausted too much; if the humid air exhaust is too large, the drying room 2 will bake The temperature will drop too much, and the drying time of the material will also be long; an adjustment plate can be set in the fresh air outlet to adjust the size of the fresh air volume when the system is running for the first time.

In this way, through the adjustment of the ratio and size of the primary return air volume and the secondary return air volume, the optimal matching of the heat exchange of the dehumidification surface cooler and the cooling capacity of the compressor is achieved, which solves the problem that the return air of the traditional heat pump drying system through the dehumidification surface cooler is too large. The problem.

In this embodiment, the blower 105 in the heat pump unit 1 is connected to the horizontally arranged air supply chamber 7 through the air supply pipe 4, and the horizontal slit air supply port 201 on the right side of the horizontal air supply chamber 7 is communicated with the inner cavity of the drying chamber 2, and the drying chamber 2. The inner cavity and the horizontal air return chamber 8 are communicated through the air outlet 202 of the horizontal slit, and the horizontal air return chamber 8 is connected with the first exhaust pipe 5 and the second exhaust pipe 6, and the first exhaust pipe 5 discharges the air. To the outside, the second exhaust duct 6 (including the upper part and the lower part in this drawing) is finally connected with the heat pump unit 1 .

In this embodiment, the drying system is driven by the blower 105 to make the air flow power, including the hot air flow from the heat pump unit 1 to the drying chamber 2 and the return air flow from the drying chamber 2 into the heat pump unit 1. In addition, through the heat pump unit 1 The heating and cooling can achieve the removal of moisture in the air.

This embodiment provides a horizontal air supply structure. The hot air enters the horizontal air supply chamber 7 through the air supply pipe 4, and the hot air is sent to the drying chamber horizontally through the horizontal slit air supply port 201 on the right side of the horizontal air supply chamber 7. 2, the material is heated, so that the moisture in the material is evaporated and mixed with the air, and then flows into the horizontal return air chamber 8 through the horizontal slit air outlet 202, and then passes through the second exhaust pipe 6 to the heat pump unit, so that the air in the drying chamber 6 The air is heated and cooled by a cycle.

When the system is running, the relatively dry cold air is mixed with the primary return air entering the heat pump unit from the primary return air outlet, and then condenses and releases heat through the high-temperature refrigerant in the internal cooling and hot surface cooler 115 and transfers heat through the partition wall, so that the air is heated and Drying; the secondary return air entering the heat pump unit 1 from the secondary return air outlet first passes through the dehumidification surface cooler 114 to perform low-temperature refrigerant evaporation and heat transfer and heat transfer from the partition wall, so that these secondary return air is cooled and dehumidified (condensed water is discharged through the water receiving tray) Then, it is heated by the inner cooling hot surface cooler 115 .

During the air drying and heating process, when the moisture content of the humid air minus the moisture content of the fresh air is greater than the set value, the fresh air valve 103 is opened. The inner humid air is discharged through the first exhaust pipe 5 and the second exhaust pipe 6, and the air in the drying chamber 2 is dried by replacement; , to achieve the purpose of fresh air preheating and system energy saving.

In the present invention, the ventilation valve is arranged between the blower and the internal cooling and heating surface cooler, and the ventilation valve is directly connected to the chassis: through the operation of the blower, the ventilation valve is opened, and a large amount of fresh air is sucked into the blower through the ventilation valve. The same amount of moist air is discharged through the first air exhaust pipe 5 to meet the requirements of high moisture content in the initial drying stage of the material, and ventilation and energy-saving drying in the early stage.

In addition, when the system is shut down for maintenance, open the side door of the chassis, and use a water gun to thoroughly clean the flammable dust and oil stains on the inner cooling and heating surface cooler and dehumidification surface cooler. Safety and reliability. Because the blower of the heat pump unit is set above the chassis, there are no other electrical appliances in the space of the inner cooling and heating surface cooler and the dehumidifying surface cooler, so the inner cooling and heating surface cooler and the dehumidifying surface cooler can be washed with water.

Overall, the present invention has the following advantages:

First, by operating the heat pump unit 1, the drying system provided by the present invention can timely control the return air volume of the dehumidification surface cooler 114, the return air volume of the external cold and hot surface cooler 109 and the inner cold heat surface cooler 115, and the humidity. The air discharge, as well as the heating and cooling capacity of the heat pump unit 1 itself, can greatly meet the requirements of heat balance and optimal matching.

Second, the drying system provided by the present invention solves the problems of uneven air supply and return air in the drying chamber 2 of conventional equipment and uneven discharge of wet air. The present invention can ensure that the materials in the drying chamber 2 are basically synchronously dried, that is, Solve the problems of low temperature and poor ventilation of local materials, and will not increase the running time and energy consumption of the heat pump unit due to the drying of the materials.

Third, the present invention provides an intelligent drying system according to the parameters of indoor and outdoor temperature and relative humidity that change at any time, so that the present invention can achieve the combination of ventilation drying, refrigeration drying and moist air discharge drying to achieve the maximum dehumidification. At the same time, with the gradual drying of indoor materials and the reduction of relative air humidity, different drying methods can be used to optimize the intelligent control process. This part will be described in detail in Example 2.

Example 2:

Referring to Figures 5 to 8, Figures 5 to 8 provide another specific embodiment of a drying system of the present invention, wherein Figure 5 is the pipe valve assembly under the return air heating state disclosed in Embodiment 2 of the present invention Schematic diagram of connection; Figure 6 is a schematic diagram of the connection of the pipe valve assembly in the state of return air heating and dehumidification disclosed in Embodiment 2 of the present invention; Figure 7 is the connection of the pipe valve assembly in the state of high temperature return air refrigeration disclosed in Embodiment 2 of the present invention Schematic diagram; FIG. 8 is a schematic diagram of the connection of the pipe valve assembly under the low temperature refrigeration state of the return air disclosed in Embodiment 2 of the present invention;

As shown in FIG. 5 to FIG. 8 , the pipe valve assembly provided in this embodiment includes a front four-way valve 30 , a rear four-way valve 31 , an external cooling and heating solenoid valve 32 , a dehumidification solenoid valve 33 , a post-cooling solenoid valve 34 , and an expansion valve. 35. The first one-way valve 36, the second one-way valve 37, the third one-way valve 38, the fourth one-way valve 39, and the fifth one-way valve 40, wherein the exhaust port of the compressor 113 is connected to the The port D of the front four-way valve 30 is connected, the port E of the front four-way valve 30 is connected to the port D of the rear four-way valve 31, and the port C of the front four-way valve 30 is connected to one end of the inner cooling hot surface cooler 115 The port S of the front four-way valve 30 and the port S of the rear four-way valve 31 are connected in parallel with the air return port of the compressor 113 , and the port E of the rear four-way valve 31 is connected to one end of the dehumidifying surface cooler 114 connection, the port C of the rear four-way valve 31 is connected to one end of the outer cooling and heating surface cooler 109, the other end of the inner cooling and heating surface cooler 115, the inlet of the fourth one-way valve 39 is connected to the fifth The outlet of the one-way valve 40 is connected in parallel, the other end of the external cooling and heating surface cooler 109, the outlet of the second one-way valve 37 and the inlet of the third one-way valve 38 are connected in parallel, and the dehumidifying surface cooler 114 is connected in parallel. One end is connected to the outlet of the first one-way valve 36, the inlet of the first one-way valve 36 is connected to one end of the dehumidification solenoid valve 33, and the inlet of the second one-way valve 37 is connected to one end of the external heating and cooling solenoid valve, The outlet of the third check valve and the outlet of the fourth check valve are connected in parallel with the inlet of the expansion valve, the inlet of the fifth check valve is connected to one end of the after-cooling solenoid valve, and the external cooling and heating solenoid The other end of the valve, the other end of the dehumidification solenoid valve, and the other end of the aftercooling solenoid valve are connected in parallel with the expansion valve outlet.

Preferably, the heat pump unit 1 is provided with a ventilation drying mode, a combined drying mode and an air conditioning refrigeration mode, wherein:

The ventilation and drying mode includes the following steps: ① ventilation and drying, ② shutdown;

The combined drying mode includes the following steps: ① ventilation drying, ② shutdown switching, ③ return air heating and humid air discharge, ④ return air heating, ⑤ return air heating and return air cooling and humid air discharge, ⑥ return air heating and Return air cooling, ⑦ Return air heating and return air cooling and wet air discharge, ⑧ Return air heating and return air cooling, ⑨ Shutdown;

The air-conditioning cooling mode includes the following steps: ① air cooling, ② initial cooling, ③ post cooling, and ④ standby.

In this embodiment, through the energization reversal of the front four-way valve 30 and the rear four-way valve 31 and the non-reversal of power off, the external cooling and heating solenoid valve 32, the dehumidification solenoid valve 33 and the rear cooling solenoid valve 34 are energized and turned on and off. When the electricity is turned off, the refrigerant flow realizes the operation of four different flow circuits; then the compressor 113 and the blower 105 are energized to operate, and the system return air is heated, heating + cooling, initial cooling and post cooling. Combined heat pump unit. At the same time, due to the guarantee of the connection structure of the refrigeration elements, when the heat pump unit runs different refrigerant processes, the surface coolers in which the refrigerant does not flow and do not participate in heat exchange in the three surface coolers are always at the low pressure side, that is, the refrigerant in the surface cooler. Always on the gaseous side to ensure smooth flow of refrigerant without fluid accumulation and pressure fluctuations.

In the specific implementation, the external controller automatically sends the blower in the drying system to the blower according to the specified procedure according to the changes of the parameters such as fresh air temperature, fresh air relative humidity, return air temperature, return air relative humidity, fresh air moisture content, and return air moisture content. 105. Outdoor fan 110, front four-way valve 30, rear four-way valve 31, external cooling and heating solenoid valve 32, dehumidification solenoid valve 33, post-cooling solenoid valve 34, fresh air valve 103, ventilation valve 102 and compressor 113 and other loads Output signals of different on-off operation, so as to obtain different load combination control.

In this embodiment, three working modes of ventilation and drying mode, combined drying mode and air-conditioning cooling mode can be obtained by controlling the load combinations with different on-off of each load. The ventilation and drying mode has two different loads: ①ventilation drying and ②shutdown Combined operation process, the combined drying mode includes ① ventilation drying, ② shutdown switching, ③ return air heating + humid air discharge, ④ return air heating, ⑤ return air heating + return air cooling + wet air discharge, ⑥ return air heating + return air cooling, ⑦ return air heating + return air cooling + wet air discharge, ⑧ return air heating + return air cooling and ⑨ shutdown operation procedures with nine different load combinations, and the air-conditioning cooling mode has ① air cooling, ② The operation process of four different load combinations of initial cooling, ③ post cooling and ④ standby.

Specifically, when the fresh air temperature is lower than the set value (such as -9°C) or higher than the set value (such as 45°C), in order to prevent the compressor 113 from running at over-temperature, the heat pump unit 1 will automatically alarm if it is in the standby state, and the heat pump If the unit 1 is in the running state, it will automatically stop and alarm. When the fresh air temperature is within the set range (such as between -8°C and 44°C), the heat pump unit 1 remains in the standby or running state, and the controller has three working modes: ventilation drying, combined drying and air conditioning refrigeration.

The above three working modes will be described in detail below.

1. Ventilation and drying mode

Process 1. Ventilation and drying

When the moisture content of return air - moisture content of fresh air is greater than or equal to the set value (such as 12g/kg), the blower in the load combination is powered on and the ventilation valve is powered on. A large amount of outdoor relatively dry air is sucked in from the ventilation valve, and an equal amount of humid air in the drying chamber 2 is discharged from the first exhaust pipe 5 of the humid air passage.

Process two, shutdown

When the moisture content of the return air - the moisture content of the fresh air is less than or equal to the set value (such as 10g/kg), the controller shuts down: the blower in the load combination is powered off and shut down, the ventilation valve is powered off, and the operation is completed.

In this mode, the heat pump unit does not participate in the operation, and the system operating power is small. It is suitable for drying materials with relatively dry fresh air, low drying requirements and long drying time.

2. Combined drying mode

Process 1. Ventilation and drying

When the return air moisture content - the fresh air moisture content ≥ the set value (such as 20g/kg), the supply fan in the load combination is energized and the ventilation valve is energized to open, and a large amount of outdoor relatively dry air is sucked from the ventilation valve. The same amount of humid air is discharged from the first exhaust duct 5 . This process is suitable for the initial drying of the material with water on the surface or high water content before drying.

Process two, stop conversion

When the moisture content of the return air - the moisture content of the fresh air is less than or equal to the set value (such as 18g/kg), the power supply fan in the load combination will be powered off and the ventilation valve will be powered off, and the controller will automatically stop and switch to the next process.

Process three, return air heating + humid air discharge

When the relative humidity of the return air is ≥ the set value (such as 21%), and the temperature of the return air is less than or equal to the set value (such as 50°C), and the moisture content of the return air - the moisture content of the fresh air ≥ the set value (such as 26g/kg) When the load combination is energized, the blower is energized, the outdoor fan is energized, the compressor is energized, the rear four-way valve is energized and converted, the external cooling and heating solenoid valve is energized, and the fresh air valve is energized. The air in the drying chamber 2 circulates through the internal cooling and heating surface cooler of the heat pump unit and is heated. When the system is running, as the humid air is discharged in the drying chamber 2 and the moisture content of the air is reduced, the heat loss of the humid air discharge and the heat loss of the heat preservation are removed, and the heat generated by the operation of the compressor is greater than the heat absorbed by the evaporation and precipitation of the moisture in the material. The air in room 2 will gradually heat up; the cooling capacity generated by the operation of the compressor will exchange heat with the outdoor air circulation through the operation of the external cold and hot surface cooler and the outdoor fan, that is, the refrigerant absorbs the heat in the outdoor air and transfers it to the drying room 2 air process. In this process, the refrigerant flow of the heat pump unit is the return air heating.

Process four, return air heating

When the relative humidity of the return air is greater than or equal to the set value (such as 21%), and the temperature of the return air is less than or equal to the set value (such as 50°C), and the moisture content of the return air - the moisture content of the fresh air is less than or equal to the set value (such as 24g/kg) When the load combination is energized, the blower is energized, the outdoor fan is energized, the compressor is energized, the rear four-way valve is energized, and the external cooling and heating solenoid valve is energized and turned on. The air in the drying chamber 2 circulates through the internal cooling and heating surface cooler of the heat pump unit and is heated to remove the heat loss of heat preservation. Gradually heat up. At this time, the moisture content of the return air is not much different from the moisture content of the fresh air, and the humid air is not discharged to avoid the negative effect of the temperature in the drying room 2 caused by the outdoor humid air. The kinetic energy of the moisture in the material evaporating and escaping. In this process, the refrigerant flow of the heat pump unit is the return air heating.

Process five, return air heating + return air cooling + wet air discharge

When the return air relative humidity ≥ the set value (such as 21%), the set value (such as 51°C) ≤ and the return air temperature ≤ the set value (such as 59°C), and the return air moisture content - the fresh air moisture content ≥ When the set value (such as 23g/kg), in the load combination, the blower is energized, the compressor is energized, the dehumidification solenoid valve is energized and the fresh air valve is energized. The secondary return air passing through the dehumidifying surface cooler is cyclically refrigerated and dehumidified, that is, the water vapor in the humid air encounters the cooler surface and releases heat as condensed water and is discharged through the water receiving tray. After the air is mixed, it is circulated and heated by the internal cooling hot surface cooler; the fresh air is heated by the total heat exchanger 9 and then inhaled, and the moist air is discharged from the first exhaust pipe 5 . Removing the heat loss of wet air discharge and heat preservation heat loss, the heat pump cooling capacity and the heat absorption of the secondary return air are balanced, the heat pump heating and the heat absorption of water evaporation in the material, the heating capacity after the secondary return air cooling and the fresh air heating heat balance, And as the moisture in the material decreases, the heat absorbed by the evaporation of moisture in the material will gradually decrease, and the temperature of the return air sent to the drying chamber 2 will also gradually increase. The refrigerant flow of the heat pump unit in this process is return air heating and return air cooling.

Process six, return air heating + return air cooling

When the return air relative humidity ≥ the set value (such as 21%), the set value (such as 51°C) ≤ and the return air temperature ≤ the set value (such as 59°C), and the return air moisture content - the fresh air moisture content When it is less than or equal to the set value (such as 21g/kg), in the load combination, the blower is energized, the compressor is energized and the dehumidification solenoid valve is energized and turned on. The secondary return air passing through the dehumidifying surface cooler is cyclically refrigerated and dehumidified, that is, the water vapor in the humid air encounters the cooler surface and releases heat as condensed water and is discharged through the water receiving tray. After the air is mixed, it is circulated and heated through the internal cooling hot surface cooler. The refrigerant flow of the heat pump unit in this process is return air heating and return air cooling.

Process seven, return air heating + return air cooling + wet air discharge

When the return air relative humidity ≥ the set value (such as 21%), and the return air temperature ≥ the set value (such as 60 ℃), and the return air humidity - fresh air moisture content ≥ the set value (such as 20g/kg) When the load combination is energized, the blower is energized, the compressor is energized, the dehumidification solenoid valve is energized and the fresh air valve is energized. The refrigerant flow of the heat pump unit in this process is return air heating and return air cooling.

Process eight, return air heating + return air cooling

When the relative humidity of the return air is greater than or equal to the set value (such as 21%), and the temperature of the return air is greater than or equal to the set value (such as 60°C), and the moisture content of the return air - the moisture content of the fresh air is less than or equal to the set value (such as 18g/kg) When the load combination is energized, the blower is energized, the compressor is energized, and the dehumidification solenoid valve is energized and turned on. The refrigerant flow of the heat pump unit in this process is return air heating and return air cooling.

Process nine, shutdown

When the relative humidity of the return air is less than or equal to the set value (such as 20%), and the holding time is greater than or equal to the set value (such as 20 minutes), the system is in the process of ⑤ return air heating + return air cooling + wet air discharge, ⑥ return air heating + return air When cooling, ⑦return air heating+return air cooling+moist air discharge and ⑧return air heating+return air cooling are running, the controller shuts down and displays that the operation has been completed.

Operation description of combined drying mode:

1. According to the detected fresh air temperature, fresh air relative humidity, return air temperature and return air relative humidity, as well as the calculated fresh air moisture content and return air moisture content, according to the control conditions: ① ventilation and drying, ③ return air heating, ④Return air heating + moist air discharge, ⑤Return air heating + return air cooling + moist air discharge, ⑥Return air heating + return air cooling, ⑦Return air heating + return air cooling + moist air discharge, ⑧Return air heating + return air One of the seven processes of air cooling is automatically selected to start running. If the operating conditions of the seven processes are not satisfied, the controller will not operate and display that the material does not need to be dried.

2. The system operates in accordance with the above-mentioned combined drying mode. The controller achieves the maximum dehumidification mechanism in the combined application of ventilation drying, wet air discharge and return air cooling, and as the indoor materials gradually dry and the relative air humidity decreases, different Drying method, requirements for intelligent and optimal control: that is, the moisture content of the material at the beginning is high, and the material should be ventilated and dried in the early stage of drying; if the moisture content of the material at the beginning is not high, it should be return air heating + moist air discharge + return Air cooling and return air heating + return air cooling are carried out separately, so that the material can be dehumidified quickly, the heat can be fully utilized, and the dryness of the material is high.

3. The system operates the fresh air intake and the wet air discharge. According to the low return air temperature, the difference between the return air moisture content and the fresh air moisture content is large, and the return air temperature is high, the return air moisture content and the fresh air moisture content. The optimization mechanism with small difference is carried out; when the material is dried, the temperature of the return air rises quickly, the relative humidity of the return air is not too high, the drying speed of the material is fast and the deformation is small.

4. Avoid the problem that the traditional control does not have or is difficult to accurately set the operation of wet air discharge when the return air starts to heat, and the wet air cannot be discharged in time, so that the moisture content of the return air is too large, resulting in a slow rise in the return air temperature; The reason for this is that the specific heat of water vapor is much greater than that of dry air, and the heat required to increase the temperature of humid air with more moisture is much greater than that of humid air with less moisture.

5. The air moisture content is a function of temperature and relative humidity. The controller calculates according to the corresponding formula, and then obtains the difference between the return air moisture content and the fresh air moisture content. Because the air moisture content is a parameter that accurately reflects the amount of water in the unit air, the system uses the difference between the return air moisture content and the fresh air moisture content for dehumidification control, which is an optimized and precise control method.

3. Air conditioning cooling mode

This mode is used to quickly cool the drying chamber 2 and the materials after the operation of the combined drying mode is completed, so as to make the temperature in the drying chamber 2 comfortable, so as to quickly turn over the materials and improve work efficiency. The air-conditioning cooling mode can be selected to operate according to needs.

Process 1, air cooling

When the return air temperature is greater than or equal to the set value (such as 50°C), the supply fan in the load combination is energized and the ventilation valve is energized to open. A large amount of relatively low-temperature fresh air is drawn into the air supply duct from the ventilation valve, and the hot air in the drying chamber 2 is discharged through the first air exhaust duct 5 .

This process uses the relatively low temperature fresh air to mix with the hot air in the drying chamber 2 to achieve the effect of energy saving and cooling, and avoids the problem that the structure of the heat pump compressor for drying is not suitable for high temperature air cooling, and also uses the fresh air and the high temperature in the drying chamber 2 When the air is mixed, the moisture in the fresh air will be discharged together with the mixed air, without affecting the mechanism of the dryness of the materials in the drying chamber 2.

Process 2, initial cooling

Set value (such as 49°C) ≤ when return air temperature ≤ set value (such as 36°C), in the load combination, the supply fan is energized, the outdoor fan is energized, the compressor is energized, the front four-way valve is energized, and the dehumidification electromagnetic The valve is energized to open. The secondary return air passing through the dehumidification surface cooler is circulated and cooled, and the heat generated by the operation of the compressor is exchanged with the outdoor air circulation through the operation of the external cooling and heating surface cooler and the external fan. In this process, the refrigerant flow of the heat pump unit is the initial cooling of the return air.

This process utilizes the cooling effect of the dehumidification surface cooler with small air volume and large temperature difference to reduce the evaporating temperature of the refrigerant, make the evaporating temperature and condensing temperature of the heat pump moderate, make the compression ratio of the compressor operate in an optimal range, and make the compressor suitable for drying Refrigeration and cooling of higher temperature air in room 2.

Process three, after cooling

Set value (such as 35°C) ≤ when return air temperature ≤ set value (such as 16°C), in the load combination, the supply fan is energized, the outdoor fan is energized, the compressor is energized, the front four-way valve is energized and converted, and after cooling The solenoid valve is energized to open. The return air passing through the inner cooling and heating surface cooler is circulated for cooling, and the heat generated by the operation of the compressor is exchanged with the outdoor air circulation through the operation of the outer cooling and heating surface cooler and the outdoor fan. In this process, the refrigerant flow of the heat pump unit is the cooling after return air.

This process utilizes the cooling effect of the large air volume and small temperature difference of the internal cooling hot surface cooler to increase the evaporating temperature of the refrigerant, make the evaporating temperature and the condensing temperature of the heat pump moderate, and enable the compressor to achieve the effect of lower temperature refrigeration, which can meet the requirements of some materials after drying. Requires low temperature turnaround.

Process four, standby

When the return air temperature is less than or equal to the set value (such as 15°C), the controller will stand by, and the rest of the loads will be powered off except for the blower.

To sum up, the present invention has the characteristics of fast speed, high efficiency, energy saving, intelligent control, optimized operation, safety and reliability, low cost, simple operation, convenient maintenance and low operation cost.

Example 3:

Referring to FIG. 9, FIG. 9 provides another specific embodiment of the present invention, wherein, FIG. 9 is a schematic diagram of the overall structure of the drying system disclosed in Embodiment 3 of the present invention.

In this embodiment, the air outlets 201 are evenly distributed on the upper side wall of the drying chamber 2 from left to right, and the air outlets 202 are evenly distributed on the lower side wall of the drying chamber 2 from left to right.

In this embodiment, the blower 105 is connected to the vertically arranged air supply room (adjusted from the horizontally arranged air supply room of Embodiment 1 to the vertical air supply room) through the air supply pipe 4, and the vertical air supply port of the air supply room is vertically arranged 201 communicates with the drying chamber 2, the air outlet 202 communicates with the drying chamber 2, and finally can be connected with the general air return port of the heat pump unit through the second exhaust pipe 6.

In the specific implementation process, through the vertically arranged air supply port 201, the hot air is vertically sent into the drying chamber 2 from top to bottom to heat the material, so that the moisture in the material is evaporated and mixed with the air, and then enters the drying chamber through the air outlet 202. 2. The return air interlayer left at the bottom (the return air interlayer can better realize the circulation of air) returns to the heat pump unit 1 through the second exhaust pipe 6, so that the air in the drying room 2 can be heated and cooled by circulation.

The drying system provided by the present invention has been described in detail above. The principles and implementations of the present invention are described herein by using specific examples, and the descriptions of the above embodiments are only used to help understand the method and the core idea of the present invention. It should be pointed out that for those skilled in the art, without departing from the principle of the present invention, several improvements and modifications can also be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims (6)

1. A drying system is characterized by comprising a heat pump unit and a drying chamber, wherein a cold air pipe for guiding cold air in and an air supply pipe for guiding hot air out are arranged on the heat pump unit, an air supply outlet is fully distributed on the side wall of one side of the drying chamber, an air outlet is fully distributed on the side wall of the other side of the drying chamber, the air supply pipe is communicated with the air supply outlet, a first exhaust pipe and a second exhaust pipe are communicated with the air outlet, the first exhaust pipe is communicated with the outside, and the second exhaust pipe is communicated with the heat pump unit;

the widths of the air supply outlet and the air outlet are increased from top to bottom;

the heat pump unit comprises a case with an internal ventilation valve, wherein a fresh air port with a fresh air valve and communicated with the outside, an air supply port with an air supply machine and communicated with the air supply pipe, a heat recovery air port communicated with the cold air pipe and the second exhaust pipe, and an air inlet provided with a fresh air temperature sensor and a fresh air humidity sensor and communicated with the outside are sequentially arranged on the side wall above the case from left to right; a pipe valve assembly is arranged in the inner cavity of the case, a compressor is connected below the pipe valve assembly, and a dehumidification surface air cooler and an inner cooling and heating surface air cooler are connected to the left side of the pipe valve assembly; the right side of the pipe valve assembly is connected with the external cold and hot surface cooler;

the pipe valve assembly comprises a front four-way valve, a rear four-way valve, an external cooling electromagnetic valve, a dehumidification electromagnetic valve, a rear cooling electromagnetic valve, an expansion valve, a first one-way valve, a second one-way valve, a third one-way valve, a fourth one-way valve and a fifth one-way valve, wherein the exhaust port of the compressor is connected with a port D of the front four-way valve, a port E of the front four-way valve is connected with a port D of the rear four-way valve, a port C of the front four-way valve is connected with one end of the internal cooling surface cooler, a port S of the front four-way valve and a port S of the rear four-way valve are connected with the return port of the compressor in parallel, a port E of the rear four-way valve is connected with one end of the dehumidification surface cooler, a port C of the rear four-way valve is connected with one end of the external cooling surface cooler, the other, The second check valve export with third check valve entry parallel connection, the dehumidification surface cooler other end with first check valve exit linkage, first check valve entry is connected with dehumidification solenoid valve one end, the second check valve entry with outer cold heat electromagnetic valve one end is connected, the third check valve export the fourth check valve export with expansion valve entry parallel connection, the fifth check valve entry with back cold solenoid valve one end is connected, outer cold heat electromagnetic valve other end the dehumidification solenoid valve other end back cold solenoid valve other end with expansion valve exit parallel connection.

2. The drying system according to claim 1, wherein the air supply outlets are uniformly distributed from top to bottom on a left side wall of the drying chamber, and the air outlet outlets are uniformly distributed from top to bottom on a right side wall of the drying chamber.

3. The drying system according to claim 2, wherein a blowing chamber is provided between the blowing duct and the blowing port, and a return chamber is provided between the blowing port and both the first exhaust duct and the second exhaust duct.

4. The drying system according to claim 1, wherein the air supply outlets are uniformly distributed from left to right on an upper side wall of the drying chamber, and the air outlet outlets are uniformly distributed from left to right on a lower side wall of the drying chamber.

5. The drying system of claim 1, wherein the cold air duct penetrates through the first exhaust duct, and a total heat exchanger is wrapped on the cold air duct and used for transferring heat in the first exhaust duct to the inner cavity of the cold air duct.

6. The drying system of claim 1, wherein a primary air return opening and a secondary air return opening are provided in said primary air return opening, a primary air return damper is provided in said primary air return opening, and a secondary air return damper is provided in said secondary air return opening.

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