Heat pump dryer

Abstract

The present invention provides a heat pump dryer, which relates to a drying device, the heat pump dryer comprises: a compressor, a heat exchange unit, a first vapor-liquid separator, an evaporator, a first expansion valve, and a second expansion valve arranged on a circulation loop; the heat exchange unit comprises a first heat exchanger having a first flow channel and a second flow channel, a second heat exchanger having a third flow channel and a fourth flow channel, the second flow channel and the fourth flow channel are connected, the outlet of the compressor can be connected to the first end of the first flow channel, the second end of the first flow channel is connected to the first vapor-liquid separator, the gas outlet of the first vapor-liquid separator is connected to the first end of the third flow channel, the second end of the third flow channel is connected to the first expansion valve, the liquid outlet of the first vapor-liquid separator is connected to the second expansion valve, the inlet of the evaporator is respectively connected to the first expansion valve and the second expansion valve, and the outlet of the evaporator is connected to the inlet of the compressor. The heat pump dryer in the present application can produce high-temperature water.

Description

Technical Field

[0001] The invention relates to drying equipment, and in particular to a heat pump drying machine. Background Art

[0002] Drying operations are widely used in agricultural and sideline product processing, food industry, chemical industry, medicine and other industries. Usually, conventional energy sources such as coal, fuel oil, and electricity are used to provide heat energy for drying materials. This method consumes a lot of energy, has high drying costs, and causes serious environmental pollution. Therefore, it is particularly urgent to develop a new environmentally friendly drying equipment.

[0003] Using air source heat pump for drying operation can continuously provide a stable heat source for the dryer, and has the characteristics of low energy consumption and no pollution to the environment. However, the outlet water temperature of the traditional single-stage R410A heat pump system is generally only 50℃, while the heat source temperature required for drying operation is generally required to be 80-100℃, which has certain limitations for using heat pump as heat source for drying. Summary of the invention

[0004] The present invention aims to provide a heat pump dryer capable of producing high-temperature water.

[0005] The present invention provides a heat pump dryer, comprising:

[0006] A compressor, a heat exchange unit, a first vapor-liquid separator, an evaporator, a first expansion valve, and a second expansion valve are arranged on a circulation loop; the heat exchange unit includes a first heat exchanger having a first flow channel and a second flow channel, and a second heat exchanger having a third flow channel and a fourth flow channel, the second flow channel is connected to the fourth flow channel, the outlet of the compressor can be connected to the first end of the first flow channel, the second end of the first flow channel is connected to the first vapor-liquid separator, the gas outlet of the first vapor-liquid separator is connected to the first end of the third flow channel, the second end of the third flow channel is connected to the first expansion valve, the liquid outlet of the first vapor-liquid separator is connected to the second expansion valve, the inlet of the evaporator is respectively connected to the first expansion valve and the second expansion valve, and the outlet of the evaporator is connected to the inlet of the compressor.

[0007] In a preferred embodiment, the heat pump dryer further comprises: a second vapor-liquid separator connected between the inlet of the compressor and the outlet of the evaporator.

[0008] In a preferred embodiment, the fluid to be heated first passes through the fourth flow channel and then passes through the second flow channel for heating.

[0009] In a preferred embodiment, the fluid is water.

[0010] In a preferred embodiment, the refrigerant used in the heat pump dryer is a mixed refrigerant.

[0011] In a preferred embodiment, the mixed refrigerant is a mixed refrigerant of trifluorodichloroethane and difluoromethane.

[0012] In a preferred embodiment, the evaporator is a fin heat exchanger.

[0013] In a preferred embodiment, a low pressure switch is provided at the inlet of the compressor.

[0014] In a preferred embodiment, a high-pressure switch is provided at the outlet of the compressor.

[0015] In a preferred embodiment, the heat pump dryer further comprises: a four-way valve, wherein the four-way valve is respectively connected to the outlet of the compressor, the first flow channel of the first heat exchanger, the inlet of the compressor and the evaporator.

[0016] The present invention proposes a heat pump dryer with a water outlet temperature of 100°C, which can ensure that the heat pump dryer can achieve high-temperature water outlet under the condition of low-temperature water inlet to meet the drying needs. At the same time, compared with the traditional cascade heat pump system, the heat pump dryer has simpler control and more optimized components, thereby achieving the purpose of cost saving. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0018] Figure 1 It is a schematic diagram of the principle of the heat pump dryer according to the present invention.

[0019] Description of reference numerals:

[0020] 1. Compressor; 2. Heat exchange unit; 21. First heat exchanger; 211. First flow channel; 212. Second flow channel; 22. Second heat exchanger; 221. Third flow channel; 222. Fourth flow channel; 3. First vapor-liquid separator; 4. Evaporator; 5. First expansion valve; 6. Second expansion valve; 7. Second vapor-liquid separator; 8. Low-pressure switch; 9. High-pressure switch; 10. Four-way valve; 11. Intake temperature sensor; 12. Exhaust temperature sensor; 13. Ambient temperature sensor; 14. High-pressure sensor. DETAILED DESCRIPTION

[0021] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0022] like Figure 1 According to the principle schematic diagram of the heat pump dryer of the present invention, a heat pump dryer is proposed in an embodiment of the present invention, which may include: a compressor 1, a heat exchange unit 2, a first vapor-liquid separator 3, an evaporator 4, a first expansion valve 5, and a second expansion valve 6 arranged on a circulation loop; the heat exchange unit 2 includes a first heat exchanger 21 having a first flow channel 211 and a second flow channel 212, and a second heat exchanger 22 having a third flow channel 221 and a fourth flow channel 222, the second flow channel 212 and the fourth flow channel 222 are connected, the outlet of the compressor 1 can be connected to the first end of the first flow channel 211, the second end of the first flow channel 211 is connected to the first vapor-liquid separator 3, the gas outlet of the first vapor-liquid separator 3 is connected to the first end of the third flow channel 221, the second end of the third flow channel 221 is connected to the first expansion valve 5, the liquid outlet of the first vapor-liquid separator 3 is connected to the second expansion valve 6, the inlet of the evaporator 4 is respectively connected to the first expansion valve 5 and the second expansion valve 6, and the outlet of the evaporator 4 is connected to the inlet of the compressor 1.

[0023] like Figure 1 As shown, according to the principle schematic diagram of the heat pump dryer of the present invention, the compressor 1 has an inlet and an outlet, the inlet of the compressor 1 can be connected to the first end of the four-way valve 10, the second end of the four-way valve 10 is used to connect to the first flow channel 211 of the first heat exchanger 21 in the heat exchange unit 2, the third end of the four-way valve 10 is used to communicate with the inlet of the compressor 1, and the fourth end of the four-way valve 10 is used to connect to the evaporator 4. By controlling the first end of the four-way valve 10 to communicate with the second end, the third end can be connected with the fourth end. A low-pressure switch 8 can be provided at the inlet of the compressor 1, and a high-pressure switch 9 can be provided at the outlet of the compressor 1. When an abnormal situation occurs in the heat pump dryer, the high-pressure switch 9 is disconnected when the pressure of the heat pump dryer exceeds a certain level; or when the pressure of the heat pump dryer is lower than a certain level, the low-pressure switch 8 is disconnected. A high-pressure sensor 14 can be provided between the outlet of the compressor 1 and the four-way valve 10. When the pressure of the heat pump dryer exceeds a certain level, the high-pressure sensor 14 can send a pressure signal to the main control board of the heat pump dryer, and the main control board will determine whether to shut down based on the pressure signal. An exhaust temperature sensing package 12 can also be provided at the outlet of the compressor 1, which is used to detect the exhaust temperature of the compressor 1 to control the start and stop of the compressor 1, thereby protecting the compressor 1. An intake temperature sensing package 11 can also be provided at the inlet of the compressor 1, that is, between the inlet of the compressor 1 and the third end of the four-way valve 10, which is used to detect the intake temperature of the compressor 1 to control the start and stop of the compressor 1, thereby protecting the compressor 1.

[0024] like Figure 1As shown, the heat exchange unit 2 includes a first heat exchanger 21 having a first flow channel 211 and a second flow channel 212, and a second heat exchanger 22 having a third flow channel 221 and a fourth flow channel 222. The second flow channel 212 and the fourth flow channel 222 are connected, and the inlet of the fourth flow channel 222 inputs the fluid to be heated, generally water, and the fluid is preliminarily heated in the fourth flow channel 222. Since the second flow channel 212 and the fourth flow channel 222 are connected, the fluid flows out of the outlet of the fourth flow channel 222 and then flows into the inlet of the second flow channel 212, and the fluid is heated again in the second flow channel 212. After the heating is completed, the fluid flows out from the outlet of the second flow channel 212. In this way, the fluid is heated, and the fluid output from the outlet of the second flow channel 212 can be used for drying by the heat pump dryer. The heat exchange unit 2 can be an integral shell, and the second flow channel 212 and the fourth flow channel 222 are separated by a partition inside the shell. The first flow channel 211 and the third flow channel 221 are pipe bodies wound in the shell. The fluid in the first flow channel 211 and the fluid in the second flow channel 212 exchange heat, and the fluid in the third flow channel 221 and the fluid in the fourth flow channel 222 exchange heat.

[0025] like Figure 1 As shown, the outlet of the first flow channel 211 of the first heat exchanger 21 is connected to the first vapor-liquid separator 3, the gas outlet of the first vapor-liquid separator 3 is connected to the inlet of the third flow channel 221, the outlet of the third flow channel 221 is connected to the first expansion valve 5, and the liquid outlet of the first vapor-liquid separator 3 is connected to the second expansion valve 6. The gas outlet of the first vapor-liquid separator 3 is located at the upper end of the first vapor-liquid separator 3, the liquid outlet of the first vapor-liquid separator 3 is located at the bottom end of the first vapor-liquid separator 3, and the first expansion valve 5 and the second expansion valve 6 are connected to the inlet of the evaporator 4. In order to ensure the heat exchange effect of the refrigerant in the pipeline in the evaporator 4, the evaporator 4 can be selected as a fin heat exchanger, which can effectively improve the heat exchange efficiency of the evaporator 4. An environmental temperature sensing bag 13 can be provided on the evaporator 4 to control the defrosting of the evaporator 4.

[0026] In the pipeline of the heat pump dryer, the refrigerant used is a mixed refrigerant, which is a mixture of trifluorodichloroethane (R123) and difluoromethane (R32). Among them, the critical temperature of R123 is 185°C, the critical pressure is 36.1 bar, and the standard boiling point is 27.8°C; the critical temperature of R32 is 78.4°C, the critical pressure is 58.3 bar, and the standard boiling point is -51.8°C. After the compressor 1 compresses the refrigerant, the mixed refrigerant flows into the first flow channel 211 of the first heat exchanger 21 of the heat exchange unit 2, and exchanges heat with the fluid in the second flow channel 212, thereby heating the fluid in the second flow channel 212. Since the temperature of the mixed refrigerant is relatively high at this time, it can heat the fluid in the second flow channel 212 to a higher temperature. After heat exchange, the mixed refrigerant flows out from the outlet of the first flow channel 211 and flows into the first vapor-liquid separator 3. Since R32 has a low boiling point and a small amount of liquefaction, most of it is still in gaseous state. It is located at the top of the first vapor-liquid separator 3. Most of the refrigerant, which is R32, flows out from the gas outlet at the top of the first vapor-liquid separator 3 and enters the third flow channel 221 of the second heat exchanger 22. Most of the refrigerant, which is R32, exchanges heat with the low-temperature fluid in the fourth flow channel 222, thereby preliminarily heating the low-temperature fluid in the fourth flow channel 222. After the preliminary heating, the low-temperature flow channel flows into the second flow channel 212 for reheating. After the heat exchange, most of the refrigerant, which is R32, flows through the first expansion valve 5 and then enters the evaporator 4. R123 has a high boiling point, a large amount of liquefaction, and most of it is in liquid state. It is located at the bottom of the first vapor-liquid separator 3. Most of the refrigerant, which is R123, flows out from the liquid outlet at the bottom of the first vapor-liquid separator 3 and then flows through the second expansion valve 6 and then flows into the evaporator 4. The mixed refrigerant evaporates and exchanges heat in the evaporator 4, and then passes through the fourth end and the third end of the four-way valve 10 to the inlet of the compressor 1 to complete the cycle. In order to ensure that the mixed refrigerant entering the compressor 1 is in a gaseous state, a second vapor-liquid separator 7 can be provided between the inlet of the compressor 1 and the third end of the four-way valve 10 or the outlet of the evaporator 4.

[0027] In the heat exchange unit 2, if the fluid to be heated is water, the second heat exchanger 22 can heat the low-temperature water to a certain temperature first, for example, heating the 15-degree water to about 50 degrees, and then the first heat exchanger 21 can heat the water at a certain temperature again, and then heat the water to 100 degrees. In this way, the water heated by the first heat exchanger 21 can be directly used to dry items.

[0028] The present invention proposes a heat pump dryer with a water outlet temperature of 100°C, which can ensure that the heat pump dryer can achieve high-temperature water outlet under the condition of low-temperature water inlet to meet the drying needs. At the same time, compared with the traditional cascade heat pump system, the heat pump dryer has simpler control and more optimized components, thereby achieving the purpose of cost saving.

[0029] In combination with the description of the accompanying drawings and the specific embodiments of the present invention, the details of the present invention can be more clearly understood. However, the specific embodiments of the present invention described herein are only used for the purpose of explaining the present invention and cannot be understood as limiting the present invention in any way. Under the guidance of the present invention, technicians can conceive of any possible variations based on the present invention, which should be regarded as belonging to the scope of the present invention. It should be noted that when an element is referred to as "arranged on" another element, it can be directly on another element or there can also be a central element. When an element is considered to be "connected" to another element, it can be directly connected to another element or there may be a central element at the same time. The terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a mechanical connection or an electrical connection, or it can be the internal communication of two elements, it can be directly connected, or it can be indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to the specific circumstances.

[0030] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A heat pump dryer, characterized in that: The heat pump dryer comprises: A compressor (1), a heat exchange unit (2), a first vapor-liquid separator (3), an evaporator (4), a first expansion valve (5), and a second expansion valve (6) are arranged on a circulation loop; the heat exchange unit (2) comprises a first heat exchanger (21) having a first flow channel (211) and a second flow channel (212), and a second heat exchanger (22) having a third flow channel (221) and a fourth flow channel (222); the second flow channel (212) and the fourth flow channel (222) are connected; the outlet of the compressor (1) can be connected to the first flow channel (211); the first flow channel (211) is connected to the first vapor-liquid separator (3); The gas outlet of the first vapor-liquid separator (3) is connected to the third flow channel (221), the third flow channel (221) is connected to the first expansion valve (5), the liquid outlet of the first vapor-liquid separator (3) is connected to the second expansion valve (6), the inlet of the evaporator (4) is connected to the first expansion valve (5) and the second expansion valve (6), respectively, and the outlet of the evaporator (4) is connected to the inlet of the compressor (1); the fluid to be heated first passes through the fourth flow channel (222) and then passes through the second flow channel (212) for heating; the refrigerant used in the heat pump dryer is a mixed refrigerant.

2. The heat pump dryer according to claim 1, characterized in that: The heat pump dryer further comprises: a second vapor-liquid separator (7) connected between the inlet of the compressor (1) and the outlet of the evaporator (4).

3. The heat pump dryer according to claim 1, characterized in that: The fluid is water.

4. The heat pump dryer according to claim 1, characterized in that: The mixed refrigerant is a mixed refrigerant of trifluorodichloroethane and difluoromethane.

5. The heat pump dryer according to claim 1, characterized in that: The evaporator (4) is a fin heat exchanger.

6. The heat pump dryer according to claim 1, characterized in that: A low-pressure switch (8) is provided at the inlet of the compressor (1).

7. The heat pump dryer according to claim 1, characterized in that: A high-pressure switch (9) is provided at the outlet of the compressor (1).

8. The heat pump dryer according to claim 1, characterized in that: The heat pump dryer further comprises: a four-way valve (10), wherein the four-way valve (10) is respectively connected to the outlet of the compressor (1), the first flow channel (211) of the first heat exchanger (21), the inlet of the compressor (1) and the evaporator (4).

Images