CN116086064A

CN116086064A - Defrosting control method and device for freeze dryer, freeze dryer and storage medium

Info

Publication number: CN116086064A
Application number: CN202211641451.4A
Authority: CN
Inventors: 马善乐; 袁顺涛; 刘占杰; 李华昭; 梁娜; 张翰; 蒋鲁鸣; 李军锋
Original assignee: Qingdao Haier Biomedical Co Ltd
Current assignee: Qingdao Haier Biomedical Co Ltd
Priority date: 2022-12-20
Filing date: 2022-12-20
Publication date: 2023-05-09

Abstract

The application relates to the technical field of freeze drying, and discloses a defrosting control method for a freeze dryer, wherein the freeze dryer comprises a refrigerant circulation loop, a bypass pipeline and a control valve, the refrigerant circulation loop comprises a compressor, a condenser, a throttling device and an evaporator which are sequentially connected through refrigerant pipes, one end of the bypass pipeline is connected with the refrigerant pipe between the condenser and the throttling device, the other end of the bypass pipeline is connected with the refrigerant pipe between the throttling device and the evaporator, and the control valve is arranged in the bypass pipeline; the method comprises the following steps: opening the control valve to enable the bypass pipeline to conduct the condenser and the evaporator under the condition that a defrosting instruction is received; and starting the compressor to defrost the evaporator. By using the method disclosed by the application, the return air temperature of the compressor can be reduced when the freeze dryer is defrosted. The application also discloses a defrosting control device for the freeze dryer, the freeze dryer and a storage medium.

Description

Defrosting control method and device for freeze dryer, freeze dryer and storage medium

Technical Field

The present application relates to the field of freeze drying technology, and for example, to a defrosting control method and device for a freeze dryer, and a storage medium.

Background

The freeze dryer is provided with a cold trap which creates a low-temperature environment to capture water vapor. Defrosting the cold trap is required after the freeze dryer operation is completed. If defrosting takes the form of electrical heating, not only is the structure of the conductive cryogen vessel complicated, but electrical energy is wasted.

In order to simplify the structure of a freeze dryer and defrost a cold trap more energy-effectively, a freeze dryer refrigerating apparatus having a defrosting function is disclosed in the related art, which includes a compressor, a condenser, a capillary tube, an evaporator, and a bypass line through which high temperature gas discharged from the compressor is guided to the evaporator to defrost the cold trap.

In the process of implementing the embodiments of the present disclosure, it is found that at least the following problems exist in the related art

The temperature of the refrigerant discharged by the compressor is higher, and the temperature of the high-temperature refrigerant can not be effectively reduced after passing through the evaporator, so that the return air temperature of the compressor is higher, and the service life of the compressor is influenced.

It should be noted that the information disclosed in the foregoing background section is only for enhancing understanding of the background of the present application and thus may include information that does not form the prior art that is already known to those of ordinary skill in the art.

Disclosure of Invention

The following presents a simplified summary in order to provide a basic understanding of some aspects of the disclosed embodiments. This summary is not an extensive overview, and is intended to neither identify key/critical elements nor delineate the scope of such embodiments, but is intended as a prelude to the more detailed description that follows.

The embodiment of the disclosure provides a defrosting control method and device for a freeze dryer, the freeze dryer and a storage medium, so as to reduce the return air temperature of a compressor when a cold trap is defrosted.

In some embodiments, the freeze dryer comprises a refrigerant circulation loop, a bypass pipeline and a control valve, wherein the refrigerant circulation loop comprises a compressor, a condenser, a throttling device and an evaporator which are sequentially connected through refrigerant pipes, one end of the bypass pipeline is connected with the refrigerant pipe between the condenser and the throttling device, the other end of the bypass pipeline is connected with the refrigerant pipe between the throttling device and the evaporator, and the control valve is arranged in the bypass pipeline; the defrosting control method for the freeze dryer comprises the following steps: opening the control valve to enable the bypass pipeline to conduct the condenser and the evaporator under the condition that a defrosting instruction is received; and starting the compressor to defrost the evaporator.

In some embodiments, the freeze dryer further comprises a fan disposed in correspondence with the condenser, the method further comprising: acquiring the return air temperature of the compressor; and controlling the fan to rotate according to the return air temperature.

In some embodiments, said controlling said fan rotation in accordance with said return air temperature comprises: and controlling the fan to rotate under the condition that the return air temperature is greater than or equal to a first temperature threshold value until the return air temperature is smaller than the first temperature threshold value.

In some embodiments, the rotational speed of the fan is positively correlated with the return air temperature.

In some embodiments, the method further comprises: acquiring the return air temperature of the compressor; and determining the opening degree of the control valve according to the return air temperature of the compressor, wherein the opening degree of the control valve is inversely related to the return air temperature.

In some embodiments, the opening the control valve comprises: judging whether the vacuum degree of the environment where the evaporator is located is smaller than a vacuum threshold value, and opening the control valve if the vacuum degree of the environment where the evaporator is located is smaller than the vacuum threshold value.

In some embodiments, the method further comprises: acquiring the temperature of the evaporator; and controlling the compressor to stop and closing the control valve under the condition that the temperature of the evaporator is greater than or equal to a defrosting temperature threshold value.

In some embodiments, the defrosting control device for a freeze dryer includes a processor and a memory storing program instructions, the processor being configured to execute the defrosting control method for a freeze dryer described above when the program instructions are executed.

In some embodiments, the freeze dryer comprises a freeze dryer body, a media circulation loop, a bypass pipeline, a control valve and the defrosting control device for the freeze dryer, wherein the refrigerant circulation loop comprises a compressor, a condenser, a throttling device and an evaporator which are sequentially connected through refrigerant pipes, one end of the bypass pipeline is connected with the refrigerant pipe between the condenser and the throttling device, the other end of the bypass pipeline is connected with the refrigerant pipe between the throttling device and the evaporator, and the control valve is arranged in the bypass pipeline; the defrosting control device for the freeze dryer is installed in the freeze dryer body.

In some embodiments, the storage medium stores program instructions that, when executed, perform the defrost control method for a freeze dryer described above.

The defrosting control method and device for the freeze dryer, the freeze dryer and the storage medium provided by the embodiment of the disclosure can realize the following technical effects:

1. The refrigerant discharged from the compressor is cooled by the condenser and then enters the evaporator through the bypass pipeline, the temperature of the refrigerant entering the evaporator is low, and the temperature impact on the evaporator is small when the evaporator is defrosted. This reduces the likelihood of deformation or breakage of the evaporator;

2. the temperature of the refrigerant entering the evaporator is lower, and the temperature of the refrigerant leaving the evaporator and entering the compressor is also lower. Therefore, the return air temperature of the compressor can be reduced, and the influence on the service life caused by the overhigh return air temperature of the compressor is avoided;

3. compared with the form that the exhaust gas of the compressor is directly communicated with the evaporator, the refrigerant also passes through the condenser, so that the travel is longer, the formation of stable suction and exhaust pressure difference of the compressor is facilitated, and the running stability of the compressor is improved.

The foregoing general description and the following description are exemplary and explanatory only and are not restrictive of the application.

Drawings

One or more embodiments are illustrated by way of example and not limitation in the figures of the accompanying drawings, in which like references indicate similar elements, and in which like reference numerals refer to similar elements, and in which:

FIG. 1 is a schematic diagram of a freeze dryer according to an embodiment of the present disclosure;

FIG. 2 is a schematic diagram of another freeze dryer provided in an embodiment of the present disclosure;

FIG. 3 is a schematic view of a freeze dryer removal housing and drying chamber provided in an embodiment of the present disclosure;

FIG. 4 is a schematic cross-sectional view of a lyophilizer provided in an embodiment of the present disclosure;

FIG. 5 is a schematic diagram of a defrost control method for a freeze dryer provided in an embodiment of the present disclosure;

FIG. 6 is a schematic diagram of another defrost control method for a freeze dryer provided in an embodiment of the present disclosure;

FIG. 7 is a schematic diagram of another defrost control method for a freeze dryer provided in an embodiment of the present disclosure;

FIG. 8 is a schematic diagram of another defrost control method for a freeze dryer provided in an embodiment of the present disclosure;

FIG. 9 is a schematic diagram of a defrost control apparatus for a freeze dryer provided in an embodiment of the present disclosure;

fig. 10 is a schematic structural view of a freeze dryer according to an embodiment of the present disclosure.

Reference numerals:

10: a freeze dryer body; 20: a defrosting control device;

100: a processor; 101: a memory; 102: a communication interface; 103: a bus;

110: a compressor; 120: a condenser; 121: a blower; 130: a throttle device; 140: an evaporator;

200: a double-pipe heat exchanger; 210: a first refrigerant flow passage; 220: a second refrigerant flow path;

310: a bypass line; 320: a control valve;

410: a drying chamber; 411: a heating device; 412: a commodity shelf; 420: a cold trap.

Detailed Description

So that the manner in which the features and techniques of the disclosed embodiments can be understood in more detail, a more particular description of the embodiments of the disclosure, briefly summarized below, may be had by reference to the appended drawings, which are not intended to be limiting of the embodiments of the disclosure. In the following description of the technology, for purposes of explanation, numerous details are set forth in order to provide a thorough understanding of the disclosed embodiments. However, one or more embodiments may still be practiced without these details. In other instances, well-known structures and devices may be shown simplified in order to simplify the drawing.

The terms first, second and the like in the description and in the claims of the embodiments of the disclosure and in the above-described figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate in order to describe embodiments of the present disclosure. Furthermore, the terms "comprise" and "have," as well as any variations thereof, are intended to cover a non-exclusive inclusion.

The term "plurality" means two or more, unless otherwise indicated.

In the embodiment of the present disclosure, the character "/" indicates that the front and rear objects are an or relationship. For example, A/B represents: a or B.

The term "and/or" is an associative relationship that describes an object, meaning that there may be three relationships. For example, a and/or B, represent: a or B, or, A and B.

The term "corresponding" may refer to an association or binding relationship, and the correspondence between a and B refers to an association or binding relationship between a and B.

The freeze dryer is provided with a cold trap which creates a low-temperature environment to capture water vapor. Defrosting the cold trap is required after the freeze dryer operation is completed. If defrosting takes the form of electrical heating, not only is the structure of the conductive cryogen vessel complicated, but electrical energy is wasted. In order to simplify the structure of a freeze dryer and defrost a cold trap more energy-effectively, a freeze dryer refrigerating apparatus having a defrosting function is disclosed in the related art, which includes a compressor, a condenser, a capillary tube, an evaporator, and a bypass line through which high temperature gas discharged from the compressor is guided to the evaporator to defrost the cold trap. The related art has a problem in that the temperature of the refrigerant discharged through the compressor is high, and the temperature of the high-temperature refrigerant cannot be effectively reduced after passing through the evaporator, so that the return air temperature of the compressor is high, thereby affecting the service life of the compressor.

According to the embodiment of the disclosure, the bypass pipeline is arranged between the condenser and the evaporator, so that the high-temperature refrigerant discharged from the compressor enters the evaporator for defrosting after being condensed and cooled during defrosting. Therefore, the return air temperature of the compressor can be reduced, the compressor is prevented from being stopped or even damaged due to overhigh temperature, the defrosting continuity of the freeze dryer is improved, and the service life of the compressor is prolonged.

Referring to fig. 1 to 4, the embodiment of the present disclosure provides a freeze dryer including a refrigerant circulation circuit, a bypass line 310, and a control valve 320. The refrigerant circulation circuit includes a compressor 110, a condenser 120, a throttling device 130, and an evaporator 140, which are sequentially connected through refrigerant pipes. One end of the bypass line 310 is connected to a refrigerant pipe between the condenser 120 and the throttle device 130, and the other end is connected to a refrigerant pipe between the throttle device 130 and the evaporator 140. A control valve 320 is provided in the bypass line 310. The freeze dryer also comprises an electronic control module, and the electronic control module comprises a processor. The processor is used for controlling the control valve, the compressor and the fan according to the instruction.

In the embodiment of the disclosure, a low-temperature environment is created through a refrigerant circulation loop. Specifically, the refrigerant circulation circuit includes a compressor 110, a condenser 120, a throttle device 130, and an evaporator 140. The refrigerant enters the compressor 110 in a gaseous form, is compressed by the compressor 110 to become a high-temperature and high-pressure gaseous refrigerant, and then enters the condenser 120 through the exhaust gas of the compressor 110. The high-temperature and high-pressure refrigerant is reduced in temperature in the condenser 120 and then introduced into the evaporator 140 in a liquid state through the restriction 130. The pressure of the refrigerant introduced into the evaporator 140 is reduced, the refrigerant is evaporated into a gaseous refrigerant and absorbs heat during the evaporation to reduce the temperature of the evaporator 140. The gaseous refrigerant in the evaporator 140 is sucked by the suction end of the compressor 110 and then subjected to the next refrigerating cycle. Through the circulation flow of the refrigerant and the gas-liquid two-phase change, the heat of the environment where the evaporator 140 is located is continuously carried to the environment where the condenser 120 is located, so that the temperature of the environment where the evaporator 140 is located is continuously reduced.

The bypass line 310 has a first end connected to the refrigerant line between the condenser 120 and the throttle device 130, and a second end connected to the refrigerant line between the throttle device 130 and the evaporator 140. The control valve 320 is provided in the bypass line 310, and the on-off state of the bypass line 310 is switched by the control valve 320.

When the bypass line 310 is disconnected, all the refrigerant flowing out of the condenser 120 enters the evaporator 140 through the throttle device 130, and the above-described refrigeration cycle is performed.

With bypass line 310 on, the refrigerant exiting condenser 120 is split into two portions, a first portion entering evaporator 140 through bypass line 310 and a second portion entering evaporator 140 through throttle device 130. Since the refrigerant flow resistance of the bypass line 310 is much smaller than that of the throttle device 130, the first portion of refrigerant occupies a much larger proportion than the second portion of refrigerant. In some cases, it may be considered that all of the refrigerant enters the evaporator 140 through the bypass line 310. The high temperature refrigerant discharged through the compressor 110 enters the evaporator 140 through the bypass line 310 after being radiated through the condenser 120, so that the temperature of the refrigerant entering the evaporator 140 can be reduced, thereby reducing the suction temperature of the compressor 110 positioned at the rear stage of the evaporator 140.

By using the freeze dryer provided by the embodiment of the disclosure, the control valve is opened during defrosting so that the bypass pipeline conducts the evaporator and the condenser. The temperature of the refrigerant entering the evaporator is lower than in the case where the exhaust gas of the compressor is communicated with the evaporator through the bypass pipe. The temperature of the refrigerant entering the evaporator is low, and the temperature impact on the evaporator is small when the evaporator is defrosted, so that the possibility of deformation or rupture of the evaporator can be reduced; the temperature of the refrigerant entering the evaporator is lower, and the temperature of the refrigerant leaving the evaporator and entering the compressor is also lower, so that the return air temperature of the compressor can be reduced, and the influence on the service life caused by the too high return air temperature of the compressor is avoided; compared with the form that the exhaust gas of the compressor is directly communicated with the evaporator, the refrigerant also passes through the condenser, so that the travel is longer, the formation of stable suction and exhaust pressure difference of the compressor is facilitated, and the running stability of the compressor can be improved.

Optionally, the freeze dryer further includes a fan 121, and the fan 121 is disposed corresponding to the condenser 120.

When the freeze dryer is used for refrigerating, the high-temperature refrigerant exhausted by the compressor is cooled in the condenser. When the freeze dryer is defrosted, the high-temperature refrigerant discharged through the exhaust of the compressor is also discharged in the condenser. Be provided with the fan corresponding the condenser, can drive more air through the condenser through the rotation of fan to improve the freeze dryer and to the cooling effect of condenser. During refrigeration, the temperature of the refrigerant entering the evaporator can be reduced by the rotation of the fan, so that the refrigeration efficiency of the freeze dryer is improved; during defrosting, the temperature of the refrigerant entering the evaporator can be reduced through rotation of the fan, so that the return air temperature of the compressor is reduced.

Optionally, the freeze dryer further includes a double pipe heat exchanger 200, the double pipe heat exchanger 200 is configured with a first refrigerant flow channel 210 and a second refrigerant flow channel 220, the refrigerant flowing from the condenser 120 to the throttling device 130 flows through the first refrigerant flow channel 210, the refrigerant flowing from the evaporator 140 to the compressor 110 flows through the second refrigerant flow channel 220, and the refrigerant flowing through the first refrigerant flow channel 210 and the refrigerant flowing through the second refrigerant flow channel 220 exchange heat through the double pipe heat exchanger 200.

The temperature of the refrigerant flowing from the condenser to the throttling device is higher, the temperature of the refrigerant flowing from the evaporator to the compressor is lower, and heat exchange is carried out between the two refrigerant and the refrigerant through the double-pipe heat exchanger. During refrigeration, the temperature of the refrigerant flowing from the condenser to the throttling device is reduced, so that the refrigerant entering the evaporator can obtain a certain supercooling degree, and the refrigerant can be better evaporated in the evaporator to absorb heat. The temperature of the refrigerant flowing from the evaporator to the compressor is increased, so that the return air temperature of the compressor can be increased.

For the freeze dryer, the evaporator is arranged in a small and closed space, the heat quantity which can be taken away by the evaporator during refrigeration is limited, and the return air temperature of the compressor is easy to be too low. Similarly, the heat released by the refrigerant in the evaporator during defrosting is limited, and the return air temperature of the compressor is easily too high. The return air temperature of the compressor needs to be kept in a proper interval, and too high or too low is not beneficial to the smooth running of the compressor. It should be noted that, in the freeze dryer, the amount of heat to be absorbed by the evaporator is limited when the evaporator creates a low-temperature environment, and therefore, the temperature of the refrigerant flowing out through the evaporator is low. If the temperature of the refrigerant returning to the compressor is too low, the compressor may be poorly lubricated, the suction pressure may be too low, or a liquid hammer may occur.

When in refrigeration, the double-pipe heat exchanger can improve the return air temperature of the compressor on one hand, so that the compressor can stably run; on the other hand, the refrigerant entering the evaporator can obtain a certain supercooling degree, and the refrigerant is orderly evaporated in the evaporator, so that the stability of the refrigeration cycle is improved.

Optionally, as shown in connection with FIG. 2, bypass line 310 is connected in parallel with throttle 130.

When defrosting, the control valve is opened, and the refrigerant flowing out of the condenser flows through the first refrigerant flow passage of the double-pipe heat exchanger and then enters the bypass pipeline. By adopting the arrangement mode, on one hand, the temperature of the refrigerant entering the evaporator can be further reduced by cooling the condensate before entering the evaporator through the double-pipe heat exchanger during defrosting, so that the return air temperature of the compressor is reduced. On the other hand, during defrosting, the refrigerant also passes through the first refrigerant flow passage of the double-pipe heat exchanger to form a longer length, which is beneficial to the establishment of stable suction and exhaust pressure difference of the compressor. In addition, the bypass pipeline is only connected in parallel with the throttling device, and the distance between the two ends of the bypass pipeline is short, so that the bypass pipeline is convenient to set.

Optionally, as shown in connection with fig. 1, a bypass line 310 is connected in parallel with the throttling device 130 and the first refrigerant flow passage 210 of the double pipe heat exchanger 200.

During defrosting, the first refrigerant flow passage and the throttling device of the double-pipe heat exchanger are connected with the bypass pipeline in parallel as a whole. When the bypass line is on, the refrigerant flowing out of the condenser enters the evaporator through the bypass line. Thus, the circulation speed of the refrigerant can be increased, and the temperature of the refrigerant entering the evaporator can be increased, so that the defrosting speed of the evaporator is increased.

Optionally, condenser 120 is a microchannel condenser.

When the size of the flow channel is smaller than 3mm, the rule of gas-liquid two-phase flow and phase change is different from the conventional larger size, and the smaller the size of the flow channel is, the more obvious the size effect is. When the diameter of the flow channel is as small as 0.5-1mm, the convective heat transfer coefficient can be increased by 50% -100%. The condenser is a micro-channel heat exchanger, and can realize a stronger heat exchange function with a smaller refrigerant filling amount and a smaller size. This can reduce the size of the condenser and improve the heat exchange efficiency of the condenser. Because the refrigerant circulation loop has less refrigerant filling quantity, the compressor can be a compressor with smaller size. Thus, the size reduction of the freeze dryer is facilitated, and the refrigerating effect of the freeze dryer can be improved.

Optionally, the freeze dryer further includes a cold trap 420 configured with a freezing space, and the evaporator 140 includes a heat exchange tube wound in a spiral shape in the freezing space to enclose the freezing region.

As shown in fig. 3 and 4, the evaporator 140 includes a heat exchange tube wound in a spiral shape, so that the evaporator 140 has a large heat exchange area and a storage space for storing a freezing object is formed in the spiral shape.

Illustratively, cold trap 420 is open at the top for access to frozen objects. The heat exchanger is in a spiral shape, the axis of the heat exchanger faces the opening of the cold trap 420, the outer ring of the heat exchanger is close to the inner wall of the freezing space, and the inner ring of the heat exchanger is the freezing area. When the freezing object is placed in the freezing region of the evaporator 140, heat carried by the freezing object is transferred to the evaporator 140 by thermal convection and thermal radiation. With such an arrangement, the freezing effect of the evaporator 140 on the freezing object can be improved, and the freezing object of a larger size can be placed in the cold trap 420.

Optionally, the freeze dryer further comprises a drying chamber 410, a shelf 412 and a heating device 411, wherein the drying chamber 410 is positioned above the cold trap 420, a communication window is formed in the bottom of the drying chamber 410, and the cold trap 420 is in butt joint with the communication window through the opening at the top; a shelf 412 that is elevated between the drying chamber 410 and the cold trap 420; the heating device 411 is provided in the drying chamber 410.

The freeze dryer comprises a box body, and the drying chamber and the cold trap are both positioned in the box body. The bottom of the drying chamber is provided with a communication window, the top of the cold trap is open, the cold trap is positioned below the drying chamber, and the opening at the top of the cold trap is butted with the communication window at the bottom of the drying chamber. The commodity shelf is used for bearing frozen objects and is in a lifting mode. When the freeze dryer is used for dehydrating the drying object, the freezing object is placed in the shelf and transferred into the cold trap. The frozen object is frozen in the cold trap, and then the shelf is lifted up to transfer the frozen object to the drying chamber. At this time, the vacuum pump is started, and the solid water in the freeze-drying object sublimates into gaseous water along with the pressure reduction, so that the freeze-drying dehydration of the freeze-drying object is realized. When solid water sublimates, a certain amount of heat is required to be absorbed, and a heating device is arranged in the freeze-drying chamber, so that heat can be provided for sublimation of the solid water, and a freeze-dried object is dehydrated and dried better.

Optionally, the cold trap is provided with a vacuum pump interface.

When vacuum is drawn, air enters the vacuum pump through the cold trap. The solid water in the freeze-dried object sublimates into gaseous water, and the gaseous water flows to the cold trap along with air and is then captured by the evaporator in the cold trap. By adopting the arrangement form, the vacuum pump can be prevented from being damaged due to the fact that water molecules enter the vacuum pump. It should be noted that, the water molecules are captured by the evaporator and then condensed into a solid state, and the water captured by the evaporator in the solid state is not sublimated again in the vacuum environment because no heat source provides sublimation heat.

Optionally, the double pipe heat exchanger is disposed below the cold trap.

The sleeve heat exchanger is wound into a spiral shape, so that a longer length can be wound in a smaller space, and the heat exchange effect of the refrigerant in the sleeve heat exchanger is improved. The sleeve heat exchanger is arranged below the cold trap, so that the cold trap and the sleeve heat exchanger are compacter in layout, and the miniaturization of the freeze dryer is facilitated.

Optionally, the compressor is a fixed frequency compressor and the throttling device is a capillary tube.

For the freeze dryer, the evaporator is maintained in a low temperature environment rather than creating a low temperature environment most of the time, and thus the heat exchange amount of the evaporator is relatively stable. The compressor uses the fixed frequency compressor throttling arrangement to adopt the capillary, can satisfy the refrigeration demand of freeze dryer to reduce the cost of freeze dryer.

In connection with the lyophilizer illustrated in fig. 1 to 4, an embodiment of the present disclosure provides a defrost control method for a lyophilizer, as illustrated in fig. 5, including:

and S01, under the condition that a defrosting instruction is received, the freeze dryer opens a control valve so as to enable the bypass pipeline to conduct the condenser and the evaporator.

S02, starting a compressor to defrost the evaporator by the freeze dryer.

The defrosting instruction can be sent through a physical key or a virtual key, or a defrosting triggering condition is preset in the freeze dryer, and the defrosting instruction is automatically sent under the condition that the defrosting triggering condition is met. For example, the preset defrost triggering condition is when the vacuum level of the environment in which the evaporator is located is less than a vacuum threshold and the temperature of the evaporator is less than or equal to a defrost temperature threshold.

After the freeze dryer receives the defrosting command, the control valve 320 is opened to enable the bypass line 310 to conduct the condenser 120 and the evaporator 140. The freeze dryer then activates the compressor 110 to defrost the evaporator 140. With bypass line 310 on, the refrigerant exiting condenser 120 is split into two portions, a first portion entering evaporator 140 through bypass line 310 and a second portion entering evaporator 140 through throttle device 130. Since the refrigerant flow resistance of the bypass line 310 is much smaller than that of the throttle device 130, the first portion of refrigerant occupies a much larger proportion than the second portion of refrigerant. In some cases, it may be considered that all of the refrigerant enters the evaporator 140 through the bypass line 310. The high temperature refrigerant discharged through the compressor 110 enters the evaporator 140 through the bypass line 310 after being radiated through the condenser 120, so that the temperature of the refrigerant entering the evaporator 140 can be reduced, thereby reducing the suction temperature of the compressor 110 positioned at the rear stage of the evaporator 140.

By using the freeze dryer provided by the embodiment of the disclosure, the temperature of the refrigerant entering the evaporator is low, and the temperature impact on the evaporator is small when the evaporator is defrosted, so that the possibility of deformation or rupture of the evaporator can be reduced; the temperature of the refrigerant entering the evaporator is lower, and the temperature of the refrigerant leaving the evaporator and entering the compressor is also lower, so that the return air temperature of the compressor can be reduced, and the influence on the service life caused by the too high return air temperature of the compressor is avoided; compared with the form that the exhaust gas of the compressor is directly communicated with the evaporator, the refrigerant also passes through the condenser, so that the travel is longer, the formation of stable suction and exhaust pressure difference of the compressor is facilitated, and the running stability of the compressor can be improved.

In connection with the lyophilizer illustrated in fig. 1-4, another defrost control method for a lyophilizer is provided in accordance with an embodiment of the present disclosure, and in connection with fig. 6, the method includes:

S02, starting a compressor to defrost the evaporator by the freeze dryer.

S03, obtaining the return air temperature of the compressor by the freeze dryer.

S04, controlling the fan to rotate by the freeze dryer according to the return air temperature.

For the freeze dryer, the evaporator is arranged in a small and closed space, the heat quantity which can be taken away by the evaporator during refrigeration is limited, and the return air temperature of the compressor is easy to be too low. Similarly, the heat released by the refrigerant in the evaporator during defrosting is limited, and the return air temperature of the compressor is easily too high. The return air temperature of the compressor needs to be kept in a proper interval, and too high or too low is not beneficial to the smooth running of the compressor.

Therefore, the return air temperature of the compressor is taken as a key control target, the return air temperature of the compressor is obtained, and the rotation of the fan is controlled according to the return air temperature of the compressor. Illustratively, when the compressor return air temperature is high, the fan is started, and the return air temperature of the compressor located at the later stage of the condenser is indirectly reduced by reducing the temperature of the condenser. When defrosting, the refrigerant does not change in gas-liquid two phases, and only the compressor compresses the refrigerant to do work and generate heat. The heat of the condenser is taken away by the rotation of the fan, so that the heat in the defrosting circulation system consisting of the compressor, the condenser and the evaporator is transferred to the environment where the condenser is located, and the temperature of the refrigerant at each position in the defrosting circulation system is reduced. When the return air temperature of the compressor is low, the fan is turned off, so that heat loss can be reduced, and the temperature of the refrigerant entering the condenser is increased. The temperature of the refrigerant entering the condenser is higher, so that the defrosting speed can be improved on one hand, and the return air temperature of the compressor can be improved on the other hand. It should be noted that, the higher return air temperature and the lower return air temperature of the compressor are compared with the target temperature threshold of the compressor. For example, if the target temperature threshold of the compressor is between 10 ℃ and 50 ℃, the operation condition of the compressor is better, and the defrosting effect of the condenser is better, the return air temperature of the compressor is considered to be lower when the return air temperature of the compressor is lower than 10 ℃, and the return air temperature of the compressor is considered to be too high when the return air temperature of the compressor exceeds 50 ℃.

By using the defrosting control method for the freeze dryer, which is provided by the embodiment of the disclosure, the fan is controlled to rotate according to the return air temperature of the compressor when the compressor is defrosted. On one hand, the return air temperature of the compressor can be better controlled, and the compressor can be stably operated; on the other hand, the temperature of the refrigerant entering the evaporator is indirectly controlled by controlling the return air temperature of the compressor. Therefore, the refrigerant entering the evaporator can be in a reasonable temperature range, and the defrosting effect of the evaporator is achieved while the temperature impact on the evaporator is reduced.

Optionally, in step S04, controlling the fan rotation of the freeze dryer according to the return air temperature includes: and controlling the fan to rotate until the return air temperature is smaller than the first temperature threshold value under the condition that the return air temperature is larger than or equal to the first temperature threshold value.

And under the condition that the return air temperature is greater than or equal to the first temperature threshold value, the return air temperature of the compressor is considered to be high, and the fan is controlled to rotate. As the fan operates, more heat in the defrost cycle is rejected through the condenser to the condenser environment and the defrost cycle temperature is reduced. In the case where the return air temperature is less than the first temperature threshold, the compressor return air temperature is considered low. At this time, the fan stops rotating, and heat dissipation of the defrosting circulation system through the condenser is reduced. The first temperature threshold is, for example, 45 ℃. Therefore, the return air temperature of the compressor can be controlled below 45 ℃ and the compressor is in a good running condition.

Under the condition that the operating frequency of the compressor is fixed, the heat generated by the compression of the refrigerant by the compressor is relatively constant. The return air temperature of the compressor can be maintained at a relatively constant temperature if the heat generated by the compressor compressing the refrigerant balances the heat dissipated by the condenser and the heat consumed by the evaporator defrosting. In the actual running of the freeze dryer, the heat dissipated by the condenser is influenced by the ambient temperature of the condenser, the heat consumed by defrosting of the evaporator is influenced by the thickness, the distribution and other factors of the frost layer, and the relative constancy is difficult to maintain. In particular the heat consumed by the defrosting of the evaporator, is dynamically varied during defrosting. Therefore, the heat dissipated by the condenser is changed through the start and stop of the fan, so that the heat generated by the compression of the refrigerant by the compressor and the heat dissipated by the defrosting circulation system are kept balanced. Thus, the return air temperature of the compressor can be better controlled, thereby improving the defrosting effect on the evaporator and improving the running stability of the compressor.

Optionally, in step S04 the freeze dryer controls the rotation of the fan according to the return air temperature, the rotation speed of the fan is positively correlated with the return air temperature.

Under the condition of high return air temperature, the requirement of reducing the return air temperature of the compressor is considered to be urgent. At this time, the fan rotates at a very high rotational speed, thereby rapidly reducing the return air temperature of the compressor. In the case of higher return air temperatures, the need to reduce the compressor return air temperature is considered to be less stringent. At this time, the fan rotates at a higher rotating speed, so that the return air temperature of the compressor is reduced, and the phenomenon that the temperature fluctuation of the defrosting circulation system is too large is avoided. In the case where the return air temperature is low, it is considered that it is not necessary to reduce the return air temperature of the compressor. At this time, the rotation speed of the fan is reduced or the fan stops rotating, and the return air temperature of the compressor is reduced only through natural heat dissipation of the condenser. It should be noted that "high", "high" and "low" are merely to illustrate the correspondence relationship between the return air temperature and the fan rotation speed, and are not compared with the target temperature threshold or the first temperature threshold of the compressor.

The rotating speed of the fan is positively related to the return air temperature, so that the rotating speed of the fan is matched with the urgent degree of reducing the return air temperature of the compressor, and the temperature fluctuation of the defrosting circulation system is reduced while the return air temperature of the compressor is reduced. The defrosting circulation system has small temperature fluctuation, and is beneficial to the stable operation of the compressor.

In connection with the lyophilizer illustrated in fig. 1-4, another defrost control method for a lyophilizer is provided in accordance with an embodiment of the present disclosure, as illustrated in fig. 7, which includes:

S02, starting a compressor to defrost the evaporator by the freeze dryer.

S05, determining the opening degree of the control valve according to the return air temperature of the compressor by the freeze dryer, wherein the opening degree of the control valve is inversely related to the return air temperature.

In the case where the frequency of the compressor is kept constant, the flow rate of the refrigerant in the defrost cycle is mainly affected by the flow resistance. The flow resistance is mainly dependent on the length of the heat exchanger, the length of the evaporator and the throttle resistance of the throttle device, the opening of the expansion valve. The opening of the expansion valve is adjustable, and the flow resistance of the defrosting circulation system can be adjusted by adjusting the opening of the expansion valve, so that the refrigerant flow rate of the defrosting circulation system is adjusted. The higher the refrigerant flow rate of the defrosting circulation system is, the more refrigerant is compressed in unit time, and the more heat is generated by the defrosting circulation system through the compression of the refrigerant by the compressor; accordingly, the lower the refrigerant flow rate of the defrost cycle, the less heat is generated by the compressor compressing the refrigerant. The opening degree of the control valve is adjusted, so that the heat generated by the defrosting system through the refrigerant compressed by the compressor can be adjusted, and the control of the return air temperature of the compressor is indirectly realized.

Under the condition of high return air temperature, the requirement of reducing the return air temperature of the compressor is considered to be urgent. At this time, the control valve is opened with a smaller opening degree, thereby reducing the heating capacity of the compressor and indirectly reducing the return air temperature of the compressor. In the case of higher return air temperatures, the need to reduce the compressor return air temperature is considered to be less stringent. At the moment, the control valve is opened with a larger opening degree, the defrosting effect on the condenser is considered while the return air temperature of the compressor is reduced, and the larger temperature fluctuation of the defrosting circulation system is avoided. In the case where the return air temperature is low, it is considered that it is not necessary to reduce the return air temperature of the compressor. At this time, the control valve is opened at the maximum opening degree, and the heating capacity of the compressor is increased to defrost the evaporator rapidly and indirectly increase the return air temperature of the compressor. The terms "high", "high" and "low" are merely for describing the correspondence between the return air temperature and the opening degree of the control valve, and are not compared with the target temperature threshold value or the first temperature threshold value of the compressor.

The opening of the control valve is inversely related to the return air temperature, so that the opening of the expansion valve is matched with the urgent degree of reducing the return air temperature of the compressor, and the heating capacity of the compressor is balanced with the heat dissipation of the defrosting circulation system. The heat dissipation phase of the heating quantity defrosting circulation system of the compressor is balanced, so that the return air temperature of the compressor is in a proper interval, and the defrosting effect on the evaporator is improved while the running stability of the compressor is improved.

Optionally, in step S01, the freeze dryer opening control valve includes: judging whether the vacuum degree of the environment where the evaporator is positioned is smaller than or equal to a vacuum threshold value, and if so, opening a control valve.

When the freeze dryer works, the environment where the evaporator is positioned is a vacuum environment. The boiling point of water is low under vacuum environment, if defrosting solid water is carried out, the water is easy to absorb heat and sublimate into gaseous water, and is difficult to smoothly discharge. In addition, the vacuum pump may be in an operating state in a vacuum environment, and if gaseous water is sucked by the vacuum pump, the vacuum pump may be damaged.

Therefore, before defrosting, the vacuum degree of the environment where the evaporator is located is judged. Specifically, whether the vacuum degree of the environment where the evaporator is located is smaller than or equal to a vacuum threshold value is judged. If not, the defrosting condition is not met; if so, the defrost condition is deemed to be satisfied and the control valve is opened. Thus, equipment damage caused by defrosting the freeze dryer in a vacuum environment can be avoided. Illustratively, the vacuum threshold is 0.1MPa, and standard atmospheric pressure is used as the vacuum threshold, so that the freeze dryer can conveniently judge whether the freeze dryer is depressurized or not and whether the vacuum pump is running or not.

Optionally, in step S01, the freeze dryer opens the control valve, and if the vacuum level of the environment where the evaporator is located is greater than the vacuum threshold, the freeze dryer alarms.

The alarm can prompt the user through sound and light information, or can display fault codes and fault information on a display screen. Therefore, the user can be prevented from being confused when defrosting cannot be started, and the user can conveniently remove faults, so that defrosting is smoothly carried out.

In connection with the lyophilizer illustrated in fig. 1-4, another defrost control method for a lyophilizer is provided in accordance with an embodiment of the present disclosure, as illustrated in connection with fig. 8, comprising:

S02, starting a compressor to defrost the evaporator by the freeze dryer.

S06, the freeze dryer acquires the temperature of the evaporator.

S07, controlling the compressor to stop and closing the control valve by the freeze dryer under the condition that the temperature of the evaporator is greater than or equal to the defrosting temperature threshold value.

Here, the temperature of the evaporator is measured outside the evaporator. The temperature of the evaporator is used as a parameter for judging whether defrosting is finished, and the judgment result is accurate. The water melting point was 0 c when the vacuum of the evaporator environment was equal to 1 atm. Illustratively, the defrost temperature threshold is 5 ℃. In the case that the external temperature of the evaporator is greater than or equal to 5 deg.c, the frost layer is considered to have been completely melted, and defrosting is ended. At this time, the freeze dryer controls the compressor to stop and closes the control valve. Closing the control valve may prepare for the next refrigeration. By adopting the setting form, the freeze dryer can automatically judge whether defrosting is finished, thereby avoiding defrosting without defrosting or without defrosting of the freeze dryer, reducing energy consumption of defrosting of the freeze dryer and improving defrosting effect of the freeze dryer.

As shown in connection with fig. 9, an embodiment of the present disclosure provides an apparatus for defrost control of a freeze dryer, including a processor (processor) 100 and a memory (memory) 101. Optionally, the apparatus may further comprise a communication interface (Communication Interface) 102 and a bus 103. The processor 100, the communication interface 102, and the memory 101 may communicate with each other via the bus 103. The communication interface 102 may be used for information transfer. The processor 100 may invoke logic instructions in the memory 101 to perform the defrost control method for the freeze dryer of the above-described embodiments.

Further, the logic instructions in the memory 101 described above may be implemented in the form of software functional units and may be stored in a computer readable storage medium when sold or used as a stand alone product.

The memory 101 is a computer readable storage medium that can be used to store a software program, a computer executable program, such as program instructions/modules corresponding to the methods in the embodiments of the present disclosure. The processor 100 executes functional applications and data processing by executing program instructions/modules stored in the memory 101, i.e., implements the defrost control method for the freeze dryer in the above-described embodiments.

The memory 101 may include a storage program area and a storage data area, wherein the storage program area may store an operating system, at least one application program required for a function; the storage data area may store data created according to the use of the terminal device, etc. Further, the memory 101 may include a high-speed random access memory, and may also include a nonvolatile memory.

As shown in conjunction with fig. 1-4 and 10, another freeze dryer according to an embodiment of the present disclosure is provided, including: the freeze dryer body 10, the refrigerant circulation loop, the bypass pipeline 310, the control valve 320 and the defrosting control device 20 for the freeze dryer, wherein the refrigerant circulation loop is arranged on the freeze dryer body 10 and comprises a compressor 110, a condenser 120, a throttling device 130 and an evaporator 140 which are sequentially connected through refrigerant pipes; one end of the bypass line 310 is connected to a refrigerant pipe between the condenser 120 and the throttle device 130, and the other end is connected to a refrigerant pipe between the throttle device 130 and the evaporator 140; the control valve 320 is disposed in the bypass line 310; a device for defrosting control of a freeze dryer is mounted to a freeze dryer body. The mounting relationships described herein are not limited to placement within the lyophilizer, but include mounting connections to other components of the lyophilizer, including but not limited to physical, electrical, or signal transmission connections, etc. Those skilled in the art will appreciate that the means for defrost control of the freeze dryer may be adapted to the available product body, thereby enabling other possible embodiments.

Embodiments of the present disclosure provide a computer-readable storage medium storing computer-executable instructions configured to perform the above defrosting control method for a freeze dryer.

The computer readable storage medium may be a transitory computer readable storage medium or a non-transitory computer readable storage medium.

Embodiments of the present disclosure may be embodied in a software product stored on a storage medium, including one or more instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of a method according to embodiments of the present disclosure. And the aforementioned storage medium may be a non-transitory storage medium including: a plurality of media capable of storing program codes, such as a usb disk, a removable hard disk, a Read-Only Memory (ROM), a random access Memory (RAM, random Access Memory), a magnetic disk, or an optical disk, or a transitory storage medium.

The above description and the drawings illustrate embodiments of the disclosure sufficiently to enable those skilled in the art to practice them. Other embodiments may involve structural, logical, electrical, process, and other changes. The embodiments represent only possible variations. Individual components and functions are optional unless explicitly required, and the sequence of operations may vary. Portions and features of some embodiments may be included in, or substituted for, those of others. Moreover, the terminology used in the present application is for the purpose of describing embodiments only and is not intended to limit the claims. As used in the description of the embodiments and the claims, the singular forms "a," "an," and "the" (the) are intended to include the plural forms as well, unless the context clearly indicates otherwise. Similarly, the term "and/or" as used in this application is meant to encompass any and all possible combinations of one or more of the associated listed. Furthermore, when used in this application, the terms "comprises," "comprising," and/or "includes," and variations thereof, mean that the stated features, integers, steps, operations, elements, and/or components are present, but that the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof is not precluded. Without further limitation, an element defined by the statement "defrost control comprising one lyophilizer" does not exclude that there are also additional identical elements in the process, method or apparatus comprising said element. In this context, each embodiment may be described with emphasis on the differences from the other embodiments, and the same similar parts between the various embodiments may be referred to each other. For the methods, products, etc. disclosed in the embodiments, if they correspond to the method sections disclosed in the embodiments, the description of the method sections may be referred to for relevance.

Those of skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the solution. The skilled artisan may use different methods for each particular application to achieve the described functionality, but such implementation should not be considered to be beyond the scope of the embodiments of the present disclosure. It will be clearly understood by those skilled in the art that, for convenience and brevity of description, specific working procedures of the above-described systems, apparatuses and units may refer to corresponding procedures in the foregoing method embodiments, which are not repeated herein.

In the embodiments disclosed herein, the disclosed methods, articles of manufacture (including but not limited to devices, apparatuses, etc.) may be practiced in other ways. For example, the apparatus embodiments described above are merely illustrative, and for example, the division of the units may be merely a logical function division, and there may be additional divisions when actually implemented, for example, multiple units or components may be combined or integrated into another system, or some features may be omitted, or not performed. In addition, the coupling or direct coupling or communication connection shown or discussed with each other may be through some interface, device or unit indirect coupling or communication connection, which may be in electrical, mechanical or other form. The units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units may be selected according to actual needs to implement the present embodiment. In addition, each functional unit in the embodiments of the present disclosure may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit.

The flowcharts and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to embodiments of the present disclosure. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). In some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. In the description corresponding to the flowcharts and block diagrams in the figures, operations or steps corresponding to different blocks may also occur in different orders than that disclosed in the description, and sometimes no specific order exists between different operations or steps. For example, two consecutive operations or steps may actually be performed substantially in parallel, they may sometimes be performed in reverse order, which may be dependent on the functions involved. Each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems which perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.

Claims

1. The defrosting control method for the freeze dryer is characterized in that the freeze dryer comprises a refrigerant circulation loop, a bypass pipeline and a control valve, wherein the refrigerant circulation loop comprises a compressor, a condenser, a throttling device and an evaporator which are sequentially connected through refrigerant pipes, one end of the bypass pipeline is connected with the refrigerant pipe between the condenser and the throttling device, the other end of the bypass pipeline is connected with the refrigerant pipe between the throttling device and the evaporator, and the control valve is arranged in the bypass pipeline; the method comprises the following steps:

opening the control valve to enable the bypass pipeline to conduct the condenser and the evaporator under the condition that a defrosting instruction is received;

and starting the compressor to defrost the evaporator.

2. The method of claim 1, wherein the freeze dryer further comprises a fan disposed in correspondence with the condenser, the method further comprising:

acquiring the return air temperature of the compressor;

and controlling the fan to rotate according to the return air temperature.

3. The method of claim 2, wherein said controlling said fan rotation as a function of said return air temperature comprises:

And controlling the fan to rotate under the condition that the return air temperature is greater than or equal to a first temperature threshold value until the return air temperature is smaller than the first temperature threshold value.

4. The method of claim 2, wherein the step of determining the position of the substrate comprises,

the rotating speed of the fan is positively correlated with the return air temperature.

5. The method as recited in claim 1, further comprising:

acquiring the return air temperature of the compressor;

and determining the opening degree of the control valve according to the return air temperature of the compressor, wherein the opening degree of the control valve is inversely related to the return air temperature.

6. The method of any one of claims 1 to 5, wherein said opening the control valve comprises:

judging whether the vacuum degree of the environment where the evaporator is located is smaller than a vacuum threshold value, and opening the control valve if the vacuum degree of the environment where the evaporator is located is smaller than the vacuum threshold value.

7. The method according to any one of claims 1 to 5, further comprising:

acquiring the temperature of the evaporator;

and controlling the compressor to stop and closing the control valve under the condition that the temperature of the evaporator is greater than or equal to a defrosting temperature threshold value.

8. A defrost control apparatus for a freeze dryer comprising a processor and a memory storing program instructions, wherein the processor is configured to perform the defrost control method for a freeze dryer according to any one of claims 1 to 7 when running the program instructions.

9. A freeze dryer, comprising:

a freeze dryer body;

the refrigerant circulation loop is arranged on the freeze dryer body and comprises a compressor, a condenser, a throttling device and an evaporator which are sequentially connected through refrigerant pipes;

a bypass line having one end connected to a refrigerant pipe between the condenser and the throttle device and the other end connected to a refrigerant pipe between the throttle device and the evaporator;

the control valve is arranged on the bypass pipeline; and, a step of, in the first embodiment,

the defrost control apparatus for a freeze dryer of claim 8, mounted to the freeze dryer body.

10. A storage medium storing program instructions which, when executed, perform the defrost control method for a freeze dryer according to any one of claims 1 to 7.