CN220187190U

CN220187190U - Frosting detection device

Info

Publication number: CN220187190U
Application number: CN202321948173.7U
Authority: CN
Inventors: 刘志挺; 胡冠安; 周记
Original assignee: Xinyu Defense Technology Co ltd; New United Group Co Ltd
Current assignee: Xinyu Defense Technology Co ltd; New United Group Co Ltd
Priority date: 2023-07-21
Filing date: 2023-07-21
Publication date: 2023-12-15
Anticipated expiration: 2033-07-21

Abstract

The utility model relates to the technical field of heat exchangers, in particular to a frosting detection device. A frost detection apparatus, comprising: the temperature controller is used for detecting the temperature of the medium at the outlet of the heat exchanger; the pressure difference switch is used for detecting the pressure difference between the air port position of the heat exchanger and the ambient air pressure; the gravity sensor is used for detecting the weight of the heat exchanger; the current transformer is used for inducing the fan current of the heat exchanger; the optical sensor is used for detecting whether the internal gap of the heat exchanger is blocked or not; the control module is electrically connected with the temperature controller, the differential pressure switch, the gravity sensor, the current transformer and the light sensor, and when the medium temperature detected by the temperature controller is lower than a preset temperature threshold value, signals are sent to the control module, the control module collects the values of the differential pressure switch, the gravity sensor, the current transformer and the light sensor, and when at least two values reach the preset threshold value, the heat exchanger is controlled to start defrosting. The technical problems of low efficiency and low accuracy of the frosting judgment method in the prior art are solved.

Description

Frosting detection device

Technical Field

The utility model relates to the technical field of heat exchangers, in particular to a frosting detection device.

Background

During operation of the refrigeration equipment, frost tends to deposit on the heat exchanger in the refrigerated compartment where fresh food or the like is placed. The heat exchanger typically includes tubes or finned coils in which a refrigerant evaporates and dissipates heat, and a blower that blows air over the tubes or finned coils and circulates the cooled air in the refrigeration compartment. When frost is deposited on the tubes or finned coils of the heat exchanger, the air cooling capacity and effectiveness of the heat exchanger is reduced, requiring occasional defrosting thereof. Defrosting is achieved by energizing the heater, or spraying water from a nozzle, or blowing hot air through a coil.

Before defrosting, whether the heat exchanger frosts or not needs to be judged, and then the defrosting can be accurately and effectively realized. In the prior art, whether frosting is detected by adopting a visual inspection mode or whether frosting is detected by adopting a temperature or pressure detection mode is low in efficiency, and whether frosting is detected by adopting temperature or pressure is easy to be influenced by external temperature, so that the problem of inaccurate detection result is caused.

Disclosure of Invention

The utility model provides a frosting detection device which solves the technical problems that a frosting judgment mode in the prior art is low in efficiency and low in accuracy.

The technical scheme adopted by the utility model is as follows:

the utility model provides a frosting detection device for detecting frosting of a heat exchanger of a refrigerating system, wherein the refrigerating system comprises a carrier, and a heat exchanger and a fan which are arranged in the carrier, and the detection device comprises:

the temperature controller is used for detecting the temperature of the medium at the outlet of the heat exchanger;

the pressure difference switch is used for detecting the pressure difference between the air port position of the heat exchanger and the ambient air pressure;

a gravity sensor for detecting a weight of the heat exchanger;

the current transformer is used for inducing the running current of the fan of the heat exchanger;

the optical sensor is used for detecting whether the internal gap of the heat exchanger is blocked or not;

the control module is electrically connected with the temperature controller, the differential pressure switch, the gravity sensor, the current transformer and the optical sensor, and when the medium temperature detected by the temperature controller is lower than a preset temperature threshold value, signals are sent to the control module, the control module collects the values of the differential pressure switch, the gravity sensor, the current transformer and the optical sensor, and when at least two values reach the preset threshold value, the control module controls the heat exchanger to start defrosting.

According to one embodiment of the utility model, the temperature controller is replaced by a pressure controller, the pressure controller is used for detecting the pressure of the medium at the outlet of the heat exchanger, and when the pressure value detected by the pressure controller is lower than a preset pressure threshold value, the pressure controller sends a signal to the control module.

According to one embodiment of the utility model, the pressure difference switch is arranged in the carrier, the pressure difference switch is connected with a first pressure measuring pipe and a second pressure measuring pipe, the first pressure measuring pipe extends between the heat exchanger and the fan and is used for detecting the air pressure at the air port position of the heat exchanger, the second pressure measuring pipe extends out of the carrier and is used for detecting the ambient air pressure, and the pressure difference switch detects the pressure difference value between the air port position of the heat exchanger and the ambient air pressure and sends the pressure difference value to the control module.

According to one embodiment of the utility model, the gravity sensor is mounted on top of or at the bottom of the heat exchanger, and the gravity sensor detects the weight of the heat exchanger and sends it to the control module.

According to one embodiment of the utility model, the light sensor comprises a light emitter and a light receiver, and the light receiver sends a signal to the control module when the light receiver does not receive the light emitted by the light emitter.

According to one embodiment of the utility model, the light emitter emits invisible light.

According to one embodiment of the utility model, the light sensor is a correlation type photoelectric sensor, a reflector type photoelectric switch or a diffuse reflection type photoelectric switch.

According to one embodiment of the utility model, the temperature controller is replaced by a temperature switch for detecting the medium temperature at the outlet of the heat exchanger, and a signal is sent to the control module when the medium temperature detected by the temperature switch is lower than a preset temperature threshold.

According to one embodiment of the utility model, the pressure controller is replaced by a pressure switch for detecting the pressure of the medium at the outlet of the heat exchanger, and a signal is sent to the control module when the pressure value of the medium detected by the pressure switch is lower than a preset pressure threshold value.

Based on the technical scheme, the utility model has the following technical effects: the frosting detection device is provided with the temperature controller, the differential pressure switch, the gravity sensor, the current transformer, the optical sensor and the control module, and can acquire a plurality of parameters to comprehensively judge whether the heat exchanger frosts; specifically, a temperature controller is arranged to detect the medium temperature at the outlet of the heat exchanger, and when the medium temperature is lower than a preset temperature threshold value, a signal is sent to a control module, and the control module acquires the values of a differential pressure switch, a gravity sensor, a current transformer and an optical sensor again, so that the working efficiency and the accuracy of the detection device can be improved; when at least two values reach a set threshold, the control module controls the heat exchanger to start defrosting, and the multiple means are used for judging, so that misjudgment of frosting can be prevented, defrosting control of the refrigerating system is facilitated, a large amount of energy sources (adopting an electric defrosting mode) or water resources (adopting a water defrosting mode) for defrosting can be saved, the heat exchanger efficiency and refrigerating (or heating) effect of the refrigerating system are improved, and automatic operation of the refrigerating system is facilitated; because the pressure of the medium can correspondingly change at different temperatures, the temperature controller is replaced by a pressure controller, and whether frosting occurs can be judged by comparing the outlet pressure of the medium with a preset pressure threshold value.

Drawings

FIG. 1 is a schematic diagram of a frost detection apparatus for a refrigeration system according to the present utility model;

in the figure: 1-a carrier; 2-a heat exchanger; 3-a fan; 4-a temperature controller; 5-a differential pressure switch; 51-a first pressure tube; 52-a second pressure tube; 6-a gravity sensor; 7-a current transformer; 71-a cable; 8-a light sensor; 81-a light emitter; 82-light receiver.

Detailed Description

The following description of the embodiments of the present utility model will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present utility model, but not all embodiments. The following description of at least one exemplary embodiment is merely exemplary in nature and is in no way intended to limit the utility model, its application, or uses. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the present utility model. As used herein, the singular is also intended to include the plural unless the context clearly indicates otherwise, and furthermore, it is to be understood that the terms "comprises" and/or "comprising" when used in this specification are taken to specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof.

The relative arrangement of the components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present utility model unless it is specifically stated otherwise. Meanwhile, it should be understood that the sizes of the respective parts shown in the drawings are not drawn in actual scale for convenience of description. Techniques, methods, and apparatus known to one of ordinary skill in the relevant art may not be discussed in detail, but are intended to be part of the specification where appropriate. In all examples shown and discussed herein, any specific values should be construed as merely illustrative, and not a limitation. Thus, other examples of the exemplary embodiments may have different values. It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further discussion thereof is necessary in subsequent figures.

In the description of the present utility model, it should be understood that the azimuth or positional relationships indicated by the azimuth terms such as "front, rear, upper, lower, left, right", "lateral, vertical, horizontal", and "top, bottom", etc., are generally based on the azimuth or positional relationships shown in the drawings, merely to facilitate description of the present utility model and simplify the description, and these azimuth terms do not indicate and imply that the apparatus or elements referred to must have a specific azimuth or be constructed and operated in a specific azimuth, and thus should not be construed as limiting the scope of protection of the present utility model; the orientation word "inner and outer" refers to inner and outer relative to the contour of the respective component itself.

Spatially relative terms, such as "above … …," "above … …," "upper surface at … …," "above," and the like, may be used herein for ease of description to describe one device or feature's spatial location relative to another device or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "above" or "over" other devices or structures would then be oriented "below" or "beneath" the other devices or structures. Thus, the exemplary term "above … …" may include both orientations of "above … …" and "below … …". The device may also be positioned in other different ways (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

In addition, the terms "first", "second", etc. are used to define the components, and are only for convenience of distinguishing the corresponding components, and the terms have no special meaning unless otherwise stated, and therefore should not be construed as limiting the scope of the present utility model.

Example 1

As shown in fig. 1, the embodiment provides a frost detecting device for detecting frost of a heat exchanger of a refrigeration system, the refrigeration system comprises a carrier 1, a heat exchanger 2 and a fan 3, wherein the heat exchanger 2 and the fan 3 are arranged in the carrier 1, the fan 3 is positioned at one side of the heat exchanger 2, and the fan 3 improves the circulation speed of air flow passing through the heat exchanger 2; the frosting detection device comprises a control module, a temperature controller 4, a differential pressure switch 5, a gravity sensor 6, a current transformer 7 and a light sensor 8, and is used for acquiring a plurality of parameters of the heat exchanger 2 to judge whether frosting exists in the heat exchanger 2.

The carrier 1 may be a housing arranged outside the heat exchanger 2. For the heat exchanger 2, a pipeline is arranged in the heat exchanger 2, and a medium flows in from an inlet of the pipeline and flows out from an outlet of the pipeline; there is a gap between the pipes. When the surface of the heat exchanger is lower than 0 ℃, the air is not easy to frost when passing through the heat exchanger at a high flow rate. When the moisture content in the air passing through the low-temperature heat exchanger is large, condensation frosting can occur; when the moisture content of the air passing through the low-temperature heat exchanger is small, desublimation and frosting can occur. Certain changes can occur after the heat exchanger frosts, such as the weight of the heat exchanger can become heavy; the frost layer seals gaps of the heat exchanger, so that air circulation is affected; the running current of the fan motor becomes small; the pressure difference between the air before and after the heat exchanger becomes large, etc. The change can be detected to judge whether frosting occurs or not by combining the change generated after frosting of the heat exchanger 2. The fan 3 works under the drive of the motor 31, and the fan 3 can accelerate the air circulation in the gap between the pipelines of the heat exchanger 2.

The control module is electrically connected with the temperature controller 4, the differential pressure switch 5, the gravity sensor 6, the current transformer 7 and the light sensor 8, and can collect the numerical values of the temperature controller 4, the differential pressure switch 5, the gravity sensor 6, the current transformer 7 and the light sensor 8 to judge and control the heat exchanger 2 to start defrosting. The control module is optionally but not limited to a PLC controller.

The temperature controller 4 is used for detecting the medium temperature at the outlet of the heat exchanger 2, when the temperature detected by the temperature controller 4 is lower than a preset temperature threshold value, a signal is sent to the control module, the control module starts to collect the numerical values of the differential pressure switch 5, the gravity sensor 6, the current transformer 7 and the light sensor 8, and when at least two numerical values reach the set threshold value, the control module judges that the heat exchanger 2 frosts and controls the heat exchanger 2 to start defrosting. The preset temperature threshold of the temperature controller 4 may be adjusted.

As a preferable technical solution of this embodiment, the preset temperature threshold is 0 degrees.

As a preferable technical scheme of the embodiment, the temperature controller 4 may be replaced by a temperature switch, and a preset temperature threshold of the temperature switch is not adjustable, and a temperature switch with a suitable preset temperature threshold may be directly selected.

The pressure difference switch 5 is used for detecting the pressure difference between the tuyere position of the heat exchanger 2 and the ambient air pressure. Specifically, a differential pressure switch 5 is assembled in the carrier 1, the differential pressure switch 5 is connected with a first pressure measuring pipe 51 and a second pressure measuring pipe 52, and the first pressure measuring pipe 51 extends between the heat exchanger 2 and the fan 3 and is used for detecting the air pressure at the air port position of the heat exchanger 2; the second pressure measuring tube 52 extends to the outside of the carrier 1 for detecting the ambient air pressure, and the pressure difference switch 5 obtains two air pressure values to obtain a pressure difference value and sends the pressure difference value to the control module.

The gravity sensor 6 is used to detect the weight of the heat exchanger 2, which increases once the heat exchanger 2 is frosted. In particular, the gravity sensor 6 may be mounted on the carrier 1 and located at the bottom of the heat exchanger 2, detecting the weight of the heat exchanger 2. The control module collects the weight value detected by the gravity sensor 6 and compares it with a preset weight threshold value, if the weight value reaches the preset weight threshold value, frost may be formed in the heat exchanger 2. In addition, the gravity sensor 6 may be replaced in an assembling position according to an assembling manner of the heat exchanger 2, for example, when the heat exchanger 2 is hoisted, the gravity sensor 6 may be assembled on the top of the heat exchanger 2 as long as the weight of the heat exchanger 2 can be detected.

The current transformer 7 is used for detecting the current of the motor 31 of the fan 3, and once frost is formed in the heat exchanger 2, the frost layer seals the gap of the heat exchanger, so that the air circulation is affected, and the running current of the motor 31 of the fan 3 can be reduced. The current transformer 7 is electrically connected to the motor 31 of the blower 3 through a cable 71, and can obtain the running current of the motor 31. The control module collects the running current of the motor 31 obtained by the current transformer 7 and compares the running current with a preset current threshold, and if the running current reaches the preset current threshold, frost may be formed in the heat exchanger 2.

The light sensor 8 is used for detecting whether the internal gap of the heat exchanger 2 is blocked, and once frost is formed in the heat exchanger 2, the frost layer can affect the path of light, so that the light receiver 82 of the light sensor 8 cannot receive the light. The light sensor 8 includes a light emitter 81 and a light receiver 82, the light emitter 81 emits light, the light receiver 82 can be correspondingly arranged, and when the internal gap of the heat exchanger 2 is not blocked, the light receiver 82 can receive the light.

As a preferable technical solution of this embodiment, the light sensor 8 may be configured as a correlation type photoelectric sensor, the light emitter 81 and the light receiver 82 may be respectively located at two sides of the heat exchanger 2, and when the internal gap of the heat exchanger 2 is not plugged, the light emitted by the light emitter 81 may directly pass through the internal gap of the heat exchanger 2 and be received by the light receiver 82; when the internal gap of the heat exchanger 2 is blocked by the frost layer, the light emitted from the light emitter 81 is blocked by the frost layer, and the light receiver 82 cannot receive the light.

As a preferable technical scheme of the embodiment, the optical sensor 8 may be set as a reflective plate type photoelectric switch, the photoelectric switch is installed on one side of the heat exchanger, the reflective plate is installed on the other side, when the internal gap of the heat exchanger is not blocked, the light emitted by the photoelectric switch can pass through the internal gap, and after being reflected by the reflective plate, the light passes through the internal gap and is received by the photoelectric switch; when the internal gap of the heat exchanger is blocked by the frost layer, the reflected light is blocked, and the photoelectric switch cannot receive the reflected light. In addition to this, the light sensor 8 may also be provided as a diffuse reflective photoelectric switch.

As a preferred embodiment of the present embodiment, the light emitted from the light emitter 81 is visible light or invisible light.

Based on the above structure, the working principle of the frost detecting apparatus of this embodiment is:

when the temperature controller 4 detects that the medium temperature at the outlet of the heat exchanger 2 is lower than a preset temperature threshold, a signal is sent to the control module, the control module starts to collect the values of the differential pressure switch 5, the gravity sensor 6, the current transformer 7 and the light sensor 8, compares the collected values with the corresponding set thresholds, and judges that the heat exchanger 2 frosts when at least two values reach the set thresholds, and the control module controls the heat exchanger 2 to start defrosting. If the temperature controller 4 detects that the temperature of the medium at the outlet of the heat exchanger 2 is lower than 0 degree, a signal is sent to the control module, the control module starts to collect the values of the differential pressure switch 5, the gravity sensor 6, the current transformer 7 and the light sensor 8, and if the differential pressure between the position of the air inlet of the heat exchanger 2 and the ambient air pressure is greater than the preset differential pressure threshold value, and meanwhile, the light receiver 82 of the light sensor 8 does not receive the light emitted by the light emitter 81, the control module judges that the heat exchanger 2 frosts, and the control module controls the heat exchanger 2 to start defrosting.

The more the numerical values reach the set threshold, the higher the accuracy of judging frosting of the heat exchanger 2.

Example two

The present embodiment is substantially the same as the first embodiment except that the temperature controller 4 in the first embodiment is replaced with a pressure controller that detects the medium pressure at the outlet of the heat exchanger 2.

For the heat exchanger 2, the saturation pressure of the medium in the heat exchanger 2 will also vary correspondingly in the case of different temperatures, specifically, the saturation pressure values corresponding to the medium in the heat exchanger 2 at different temperatures are shown in table 1, where the pressure is the absolute pressure value in bar. Therefore, the pressure controller is adopted to detect the pressure value of the medium at the outlet of the heat exchanger 2, and whether frosting exists in the internal gap of the heat exchanger 2 can be judged by comparing the pressure value with a preset pressure threshold value. The preset pressure threshold of the pressure controller may be adjusted.

TABLE 1 corresponding pressures at different temperatures for different types of media at the outlet of heat exchanger 2

The medium in the heat exchanger 2 includes indirect coolants such as methanol solution, glycol solution, modified organic acid salt solution, and the like, in addition to the medium shown in the table.

The embodiments of the present utility model have been described in detail with reference to the drawings, but the present utility model is not limited to the above embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the spirit of the present utility model.

Claims

1. A frost detection device for detecting frost formation of a heat exchanger (2) of a refrigeration system, the refrigeration system comprising a carrier (1) and a heat exchanger (2) and a fan (3) built in the carrier (1), characterized in that the frost detection device comprises:

a temperature controller (4) for detecting the temperature of the medium at the outlet of the heat exchanger (2);

the differential pressure switch (5) is used for detecting the differential pressure between the air port position of the heat exchanger (2) and the ambient air pressure;

-a gravity sensor (6), the gravity sensor (6) being adapted to detect the weight of the heat exchanger (2);

a current transformer (7), wherein the current transformer (7) is used for sensing the running current of the fan (3) of the heat exchanger (2);

a light sensor (8), wherein the light sensor (8) is used for detecting whether an internal gap of the heat exchanger (2) is blocked;

the control module is electrically connected with the temperature controller (4), the differential pressure switch (5), the gravity sensor (6), the current transformer (7) and the light sensor (8), and when the medium temperature detected by the temperature controller (4) is lower than a preset temperature threshold value, signals are sent to the control module, the control module collects the numerical values of the differential pressure switch (5), the gravity sensor (6), the current transformer (7) and the light sensor (8), and when at least two numerical values reach a set threshold value, the control module controls the heat exchanger (2) to start defrosting.

2. A frost formation detection apparatus according to claim 1, characterized in that the temperature controller (4) is replaced by a pressure controller for detecting the pressure of the medium at the outlet of the heat exchanger (2), and that the pressure controller sends a signal to the control module when the pressure value detected by the pressure controller is lower than a preset pressure threshold.

3. A frost detecting apparatus according to any one of claims 1 to 2, wherein the pressure difference switch (5) is built in the carrier (1), the pressure difference switch (5) is connected with a first pressure measuring tube and a second pressure measuring tube, the first pressure measuring tube extends between the heat exchanger (2) and the fan (3) and is used for detecting the air pressure at the air gap position of the heat exchanger (2), the second pressure measuring tube extends outside the carrier (1) and is used for detecting the ambient air pressure, and the pressure difference switch (5) detects the pressure difference value between the air gap position of the heat exchanger (2) and the ambient air pressure and sends the pressure difference value to the control module.

4. A frost detection apparatus according to any of claims 1-2, characterized in that the gravity sensor (6) is mounted on top of or at the bottom of the heat exchanger (2), the gravity sensor (6) detecting the weight of the heat exchanger (2) and sending it to a control module.

5. A frost detection apparatus according to any of claims 1-2, wherein the light sensor (8) comprises a light emitter (81) and a light receiver (82), and wherein the light receiver (82) sends a signal to the control module when no light emitted by the light emitter (81) is received.

6. A frost detection apparatus according to claim 5, wherein the light emitter (81) emits invisible light.

7. The frost detection apparatus according to claim 5, wherein the photosensor (8) is an opposite-type photosensor, a reflective-type photoelectric switch, or a diffuse-reflective-type photoelectric switch.

8. A frost detection apparatus according to claim 1, wherein the temperature controller (4) is replaced by a temperature switch for detecting a medium temperature at the outlet of the heat exchanger (2), and when the medium temperature detected by the temperature switch is lower than a preset temperature threshold, a signal is sent to the control module.

9. A frost detection apparatus according to claim 2, wherein the pressure controller is replaced by a pressure switch for detecting the pressure of the medium at the outlet of the heat exchanger (2), and wherein a signal is sent to the control module when the pressure value of the medium detected by the pressure switch is lower than a preset pressure threshold.