A detection device and refrigeration system comprising same

Abstract

This application discloses a detection device installed on a pipe and configured to detect the liquid content of a medium in the pipe. The detection device includes a light-transmitting element, a light generator, and a light receiver. The light generator is configured to emit emitted light towards the light-transmitting element, passing through an outer boundary wall of the light-transmitting element and having a preset emission angle. The light receiver is configured to receive reflected light after the emitted light is reflected by an inner boundary wall of the light-transmitting element. The detection device of this application can directly detect whether the gaseous refrigerant discharged from the evaporator contains liquid and the amount of liquid. Based on the detection results, the refrigeration system can adjust the throttling device in a timely manner to avoid affecting the performance of the compressor and the refrigeration system.

Description

[Technical Field]

[0001] This application relates to a refrigeration system, and more particularly to a refrigeration system including a detection device. [Previous Technology]

[0002] In existing refrigeration systems, a compressor, condenser, throttling device, and evaporator are connected in sequence. Gaseous refrigerant discharged from the evaporator is then drawn into the compressor, forming a refrigerant circulation loop. If the compressor draws in gaseous refrigerant containing refrigerant droplets (i.e., liquid carryover during suction), it will affect the compressor's efficiency and the overall refrigeration system's efficiency, and may even cause liquid slugging, damaging the compressor. Refrigeration systems generally require specific detection methods and control logic to prevent liquid carryover during suction. [Summary of the Invention]

[0003] This application provides a detection device in the first category, which is disposed on a pipe and configured to detect the liquid content of a medium in the pipe; the detection device includes: a light-transmitting element disposed on the wall of the pipe, the light-transmitting element having a certain thickness and having an outer boundary wall and an inner boundary wall forming the thickness, the outer boundary wall having an outer boundary surface on the side opposite to the inner boundary wall, and the inner boundary wall having an inner boundary surface on the side opposite to the outer boundary wall, the inner boundary surface being in contact with the medium in the pipe; a light generator disposed on the outer boundary surface of the light-transmitting element, the light generator being configured to emit emitted light toward the light-transmitting element that passes through the outer boundary wall and has a preset emission angle; and a light receiver disposed on the outer boundary surface of the light-transmitting element, the light receiver being configured to receive the reflected light after the emitted light is reflected by the inner boundary wall.

[0004] According to the first category above, when the medium in contact with the inner boundary surface is entirely gas, the critical angle for total internal reflection of light on the inner boundary wall is the first total internal reflection angle; when the medium in contact with the inner boundary surface is entirely liquid, the critical angle for total internal reflection of light on the inner boundary wall is the second total internal reflection angle; wherein, the angle of the preset emission angle is between the first total internal reflection angle and the second total internal reflection angle.

[0005] According to the first category above, the cover is configured to enclose the light generator and the light receiver within the cover.

[0006] According to the first category above, the light-transmitting component is a sight glass.

[0007] According to the first category above, the light-transmitting element forms part of the tube wall or is disposed on a connecting tube that protrudes outward from the tube wall.

[0008] This application provides a refrigeration system in the second category, including: a compressor, a condenser, a throttling device, and an evaporator, wherein the compressor, the condenser, the throttling device, and the evaporator are sequentially connected by pipes to form a main circulation loop; the refrigeration system further includes: a detection device as in the first category, the detection device being disposed on a pipe between the outlet of the evaporator and the suction port of the compressor; a control device, the control device being communicatively connected to the detection device; wherein the control device is configured to determine the liquid content in the medium between the outlet of the evaporator and the suction port of the compressor based on the intensity of the emitted light emitted by the light generator and the reflected light received by the light receiver.

[0009] According to the second category above, the control device is communicatively connected to the throttling device, wherein the control device is configured to adjust the opening of the throttling device based on the liquid content in the medium.

[0010] According to the second category above, the refrigeration system has an operating mode and an adjustment mode. The control device is configured to, when the refrigeration system is in the operating mode, cause the detection device to detect the liquid content of the medium, and is configured to: maintain the operating mode when the detected liquid content of the medium is not greater than a predetermined liquid content threshold value, and switch the refrigeration system from the operating mode to the adjustment mode when the detected liquid content of the medium is greater than the predetermined liquid content threshold value.

[0011] According to the second category above, the adjustment mode includes the following operations: determining whether the suction pressure of the compressor has reached the minimum suction pressure threshold; if the compressor has reached the minimum suction pressure threshold, reducing the load of the compressor; if the compressor has not reached the minimum suction pressure threshold, reducing the opening of the throttling device.

[0012] According to the second category above, the liquid content in the medium is determined by the ratio of the intensity of the emitted light emitted by the light generator to the intensity of the reflected light received by the light receiver.

[0013] This application provides a detection device and a refrigeration system including the detection device. The detection device can directly detect whether the gaseous refrigerant discharged from the evaporator contains liquid and the amount of liquid. Based on the detection results, the refrigeration system can adjust the throttling device in a timely manner to avoid affecting the performance of the compressor and the refrigeration system.

Implementation Method

[0015] Various specific embodiments of the present invention will now be described with reference to the accompanying drawings, which form part of this specification. It should be understood that although terms indicating direction, such as "front," "rear," "upper," "lower," "left," "right," "top," "bottom," "inner," and "outer," are used in this application to describe various example structural parts and elements, their use herein is solely for illustrative purposes and is based on the orientation of the examples shown in the accompanying drawings. Since the embodiments disclosed in this application can be arranged in different orientations, these terms indicating direction are for illustrative purposes only and should not be considered as limiting.

[0016] Figure 1 is a schematic block diagram of the cooling system 190 of this application, used to show the location and function of the detection device 100 in the cooling system 190.

[0017] As shown in Figure 1, the refrigeration system 190 includes a compressor 193, a condenser 191, a throttling device 192, and an evaporator 194. These components are connected by pipes to form a closed system, which is filled with refrigerant. The refrigerant flows sequentially through the compressor 193, condenser 191, throttling device 192, and evaporator 194, enabling the refrigeration system 190 to provide cooling or heating. Specifically, the high-pressure gaseous refrigerant discharged from the exhaust port 198 of the compressor 193 flows into the condenser 191, where it releases heat and is condensed into a high-pressure liquid refrigerant. It then exits the condenser 191 and flows into the throttling device 192, where it is throttled into a low-pressure two-phase refrigerant before flowing into the evaporator 194. In the evaporator 194, it absorbs heat and evaporates into a low-pressure gaseous refrigerant. Finally, it flows out from the outlet 196 of the evaporator 194 to the suction port 197 of the compressor 193 to re-enter the compressor 193, completing the refrigerant cycle.

[0018] The pipe 101 connects the outlet 196 of the evaporator 194 and the suction port 197 of the compressor 193. In this embodiment, the refrigeration system 190 also includes a detection device 100 and a control device 110. The control device 110 is communicatively connected to the detection device 100 and to the compressor 193 and the throttling device 192. The detection device 100 is used to detect the liquid content of the gaseous refrigerant discharged from the outlet 196 of the evaporator 194 and transmits the detection result to the control device 110. The control device 110 adjusts the opening degree of the throttling device 192 based on the result detected by the detection device 100. As an example, the detection device 100 is installed on the pipe 101 between the outlet 196 of the evaporator 194 and the suction port 197 of the compressor 193.

[0019] Figures 2A and 2B show the axial sectional views of two embodiments of the pipeline, illustrating the structure and connection position of the detection device 100. In the embodiment shown in Figure 2A, the detection device 100 is disposed on the pipe wall 211 of the pipeline 101; in the embodiment shown in Figure 2B, the detection device 100 is disposed on the connecting pipe 256 of the pipeline 201. In this embodiment, one side inside the pipeline 101 is defined as the inner side, and one side outside the pipeline 101 is defined as the outer side.

[0020] As shown in Figure 2A, the detection device 100 includes a light-transmitting element 210, a light generator 203, and a light receiver 204. The light-transmitting element 210 is embedded in the pipe wall 211 of the pipe 101 to form a part of the pipe wall 211. The light generator 203 and the light receiver 204 are disposed outside the light-transmitting element 210. Specifically, the light-transmitting element 210 has an outer boundary wall 214 and an inner boundary wall 215. The outer boundary wall 214 is approximately flush with the outer surface of the pipe wall 211, and the inner boundary wall 215 is approximately flush with the inner surface of the pipe wall 211. Thus, if the liquid in the refrigerant exceeds a certain range, small droplets will form on the pipe wall 211 and the inner boundary wall 215 of the light-transmitting element 210. The outer boundary wall 214 and the inner boundary wall 215 are approximately parallel and spaced a certain distance apart. This distance forms the thickness D of the light-transmitting element 210, and the thickness D is approximately equal to the thickness of the pipe wall 211. An outer boundary surface 234 is formed on the outer side of the outer boundary wall 214 of the light-transmitting element 210 (i.e., the side opposite to the inner boundary wall 215), and an inner boundary surface 235 is formed on the inner side of the inner boundary wall 215 of the light-transmitting element 210 (i.e., the side opposite to the outer boundary wall 214). In one specific embodiment, the light-transmitting element 210 is a sight glass made of light-transmitting glass; in other embodiments, the light-transmitting element 210 may also be made of other light-transmitting materials. When the light-transmitting element 210 is a sight glass, the operator can also directly observe the situation inside the pipe 101 through the light-transmitting element 210.

[0021] Both the light generator 203 and the light receiver 204 are disposed on the outer boundary surface 234 of the light-transmitting element 210. The light generator 203 emits emitted light 321 with a preset emission angle α toward the light-transmitting element 210. The emitted light 321 is reflected on the inner boundary wall 215, and the light receiver 204 receives the reflected light 322 (see Figures 3A and 3B). In this embodiment, the emission angle refers to the angle between the emitted light 321 and the normal of the inner boundary wall 215 (see Figures 3A and 3B). The light generator 203 and the light receiver 204 are communicatively connected to the control device 110, thereby the control device 110 controls the light generator 203 to emit emitted light with a preset emission angle α, and the control device 110 receives the intensity of the reflected light received by the light receiver 204. In this embodiment, the light generator 203 includes two light generators 203 arranged along the length of the pipe 101, and the light receiver 204 is disposed between the two light generators 203. Depending on the emission angle α of the emitted light emitted by the light generators 203, the light receiver 204 can also be disposed in other positions. Furthermore, the number of light generators 203 can also be different. As an example, to facilitate the light receiver 204 in identifying the received light, the light generator 203 can emit emitted light 321 of a fixed wavelength.

[0022] In the embodiment shown in FIG. 2A, when refrigerant flows through the pipe 101 in the direction indicated by the hollow arrow, the inner boundary surface 235 can contact the refrigerant in the pipe 101. If the liquid in the refrigerant exceeds a certain range, small droplets will form on the pipe wall 211 and the inner boundary wall 215 of the light-transmitting element 210. The gaseous or liquid refrigerant inside the inner boundary surface 235 forms an optically less dense medium, and the light-transmitting element 210 between the outer boundary wall 214 and the inner boundary wall 215 outside the inner boundary surface 235 forms an optically denser medium. When the light generator 203 emits a light beam toward the light-transmitting element 210, the light beam can pass through the light-transmitting element 210 through the inner boundary wall 215 into the pipe 101, and be reflected or refracted on the inner boundary wall 215.

[0023] When refrigerant gas or refrigerant liquid flows through pipe 101, the light rays have different critical angles for total internal reflection on the inner boundary wall 215. When the refrigerant flowing through pipe 101 is gas, the critical angle for total internal reflection on the inner boundary wall 215 is the first angle for total internal reflection; when the refrigerant flowing through pipe 101 is liquid, the critical angle for total internal reflection on the inner boundary wall 215 is the second angle for total internal reflection. By controlling the incident angle α of the emitted light between the first and second angles for total internal reflection, when the refrigerant flowing through pipe 101 is gas, the emitted light is totally internally reflected and received by the light receiver 204, while when there is liquid in pipe 101, the emitted light cannot be totally internally reflected, and a portion of the emitted light is refracted and cannot be received by the light receiver 204. As a specific example, if the refrigerant is R134a and the light-transmitting element 210 is a sight glass, then the first total internal reflection angle is approximately 42.5°, the second total internal reflection angle is approximately 53°, and the preset incident angle α is approximately 42.5° to 53°. It should be noted that the critical angle for total internal reflection here refers to the incident angle at which the angle of refraction at the interface is exactly 90° when light travels from an optically denser medium to an optically less dense medium (i.e., when the refracted light travels along the interface). When the incident angle is greater than this critical angle for total internal reflection, the light can undergo total internal reflection at the inner boundary wall 215.

[0024] Still as shown in FIG2A, the detection device 100 also includes a cover 208, which can enclose the light generator 203 and the light receiver 204 within the cover 208. As an example, the cover 208 can be made of an opaque material.

[0025] In the embodiment shown in FIG. 2B, the light-transmitting element 210 is not directly disposed on the pipe wall 211 of the pipe 201 to form a part of the pipe wall 211, but is disposed on the connecting pipe 256. The connecting pipe 256 is formed by protruding outward from the pipe wall 211 along the radial direction of the pipe 201. The inner boundary wall 215 of the light-transmitting element 210 is still approximately flush with the inner surface of the pipe wall 211, so that if the liquid in the refrigerant exceeds a certain range, small droplets can still be formed on the pipe wall 211 and the inner boundary wall 215 of the light-transmitting element 210. In some embodiments, the connecting pipe 256 can be configured as a connecting flange to facilitate the disassembly of the detection device 100.

[0026] Figures 3A and 3B show the optical path schematic diagram of the detection device 100, where Figure 3A shows the optical path schematic diagram when the refrigerant does not contain droplets, and Figure 3B shows the optical path schematic diagram when the refrigerant contains droplets. It should be noted that, in order to more clearly show the different optical paths of light in refrigerant gas and refrigerant droplets, the reflection phenomenon that occurs when light passes through refrigerant droplets is not shown in the figures.

[0027] As shown in Figure 3A, when the refrigerant does not contain droplets, the emitted light 321 at a preset emission angle α emitted from the light generator 203 can undergo total internal reflection at the inner boundary wall 215 to obtain reflected light 322. The light receiver 204 can receive all the reflected light 322.

[0028] As shown in Figure 3B, when the refrigerant contains droplets (droplets 335 shown in the figure), a portion of the emitted light 321 at a preset emission angle α emitted from the light generator 203 undergoes total internal reflection at the inner boundary wall 215 to obtain reflected light 322, while the other portion is refracted at the droplet 335 to obtain refracted light 323. The light receiver 204 can only receive the reflected light 322 and cannot receive the refracted light 323.

[0029] Therefore, based on the ratio of the intensity of the emitted light 321 emitted by the light generator 203 to the intensity of the reflected light 322 received by the light receiver 204, the liquid content in the refrigerant gas can be determined. As a specific example, the intensity ratio of the reflected light 322 received by the light receiver 204 to the emitted light 321 emitted by the light generator 203 has a preset value, which reflects a predetermined liquid content threshold value in the refrigerant gas. When the intensity ratio is not greater than the preset value, it indicates that the liquid content in the refrigerant gas is not greater than the liquid content threshold value; when the intensity ratio is less than the preset value, it indicates that the liquid content in the refrigerant gas is greater than the liquid content threshold value. Based on the liquid content in the refrigerant gas reflected by this intensity ratio, the opening degree of the throttling device can be adjusted.

[0030] Figure 4 is a schematic block diagram of the control device 110 in the refrigeration system 190. As shown in Figure 4, the control device 110 includes a bus 402, a processor 404, an input interface 406, an output interface 408, and a memory 414 containing a control program 416. Each component in the control device 110, including the processor 404, the input interface 406, the output interface 408, and the memory 414, is communicatively connected to the bus 402, enabling the processor 404 to control the operation of the input interface 406, the output interface 408, and the memory 414. Specifically, the memory 414 is used to store programs, instructions, and data, while the processor 404 reads programs, instructions, and data from the memory 414 and can write data to the memory 414. By executing the programs and instructions read from the memory 414, the processor 404 controls the operation of the input interface 406 and the output interface 408.

[0031] As shown in Figure 4, the input interface 406 is communicatively connected to the compressor 193 and the detection device 100 via connection 418, and the output interface 408 is communicatively connected to the throttling device 192 and the compressor 193 via connection 422. Those skilled in the art will understand that the control device 110 can also be connected to other components of the refrigeration system 190 to realize the basic functions of the refrigeration system 190. Thus, by executing the programs and instructions in memory 414, the processor 404 controls the operation of the refrigeration system 190.

[0032] Figure 5 shows a flowchart of the adjustment mode of the refrigeration system 190. As shown in Figure 5, the refrigeration system 190 has an operating mode and an adjustment mode. In the operating mode, the control device 110 receives the detection results from the detection device 100. When the detection device 100 detects that the liquid content of the refrigerant gas in the pipe 101 is within the liquid content threshold range, the control device 110 maintains the operating mode of the refrigeration system 190. When the detection device 100 detects that the liquid content of the refrigerant gas in the pipe 101 is greater than the liquid content threshold, the control device 110 switches the refrigeration system 190 from the operating mode to the adjustment mode. In the adjustment mode, based on the data from the compressor 193 and the detection device 100 input through the input interface 406, the control device 110 sends a control signal to the throttling device 192 through the output interface 408 to adjust the liquid content of the refrigerant gas in the pipe 101 to within the liquid content threshold range. When the detection device 100 detects that the liquid content of the refrigerant gas in the pipeline 101 is within the liquid content limit range, the control device 110 switches the self-adjustment mode of the refrigeration system 190 back to the operating mode.

[0033] In the adjustment mode, the control device 110 first determines whether the suction pressure of the compressor 193 has reached the minimum suction pressure threshold. If the compressor 193 has not reached the minimum suction pressure threshold, the opening of the throttling device 192 is reduced. If the compressor 193 has reached the minimum suction pressure threshold, it means that the opening of the throttling device 192 cannot be further reduced, therefore the control device 110 reduces the load on the compressor 193.

[0034] The refrigeration system of this application uses a detection device installed on the pipe between the evaporator outlet and the compressor suction port to directly detect the liquid content in the refrigerant gas discharged from the evaporator and drawn into the compressor. The detection results are timely and accurate. Furthermore, based on the detected results, the control device can promptly adjust the refrigeration system to prevent liquid from being carried into the compressor suction, thus preventing any impact on the performance of the compressor and the refrigeration system. This detection device of the present application is particularly suitable for detecting the liquid content in gases containing small amounts of liquid.

[0035] Although this disclosure has been described with reference to examples of the embodiments outlined above, various alternatives, modifications, variations, improvements, and / or substantially equivalents, whether known or foreseeable now or soon, may be apparent to those skilled in the art. Furthermore, the technical effects and / or technical problems described in this specification are illustrative and not limiting; therefore, the disclosure in this specification may be used to solve other technical problems and have other technical effects and / or solve other technical problems. Thus, the examples of embodiments of this disclosure as stated above are intended to be illustrative and not limiting. Various changes may be made without departing from the spirit or scope of this disclosure. Therefore, this disclosure is intended to include all known or earlier developed alternatives, modifications, variations, improvements, and / or substantially equivalents. [Simplified Explanation of the Diagram]

[0014] Figure 1 is a schematic block diagram of the refrigeration system 190 according to this application; Figure 2A is a partial cross-sectional view of one embodiment of the pipe 101 shown in Figure 1; Figure 2B is a partial cross-sectional view of another embodiment of the pipe 201; Figure 3A is an optical path diagram of the detection device 100 shown in Figure 1 when the refrigerant does not contain droplets; Figure 3B is an optical path diagram of the detection device 100 shown in Figure 1 when the refrigerant contains droplets; Figure 4 is a schematic block diagram of the control device 110 in the refrigeration system 190 shown in Figure 1; Figure 5 is a flowchart of the adjustment mode of the refrigeration system 190 shown in Figure 1.

Claims

1. A detection device for a refrigeration system, wherein the detection device is configured to be disposed on a pipe between an evaporator and a compressor and configured to detect the liquid content of a medium in the pipe, wherein the detection device comprises: a controller including a processor and a memory; a light-transmitting element disposed on a wall of the pipe, wherein the light-transmitting element has a thickness and has an outer boundary wall and an inner boundary wall forming the thickness, the outer boundary wall having an outer boundary surface on a side opposite to the inner boundary wall, the inner boundary wall having an inner boundary surface on a side opposite to the outer boundary wall, and the inner boundary surface being in contact with the medium in the pipe; A light generator is disposed on the outer boundary surface of the light-transmitting element, wherein the light generator is communicatively coupled to the controller, and the controller is configured to control the light generator to emit emitted light toward the light-transmitting element and through the outer boundary wall at a preset emission angle (α); and a light receiver is disposed on the outer boundary surface of the light-transmitting element, wherein the light receiver is communicatively coupled to the controller, and the light receiver is configured to receive the reflected light after the emitted light is reflected by the inner boundary wall.

2. The detection device as described in claim 1, wherein: When the medium in contact with the inner boundary surface is entirely gas, the critical angle for total internal reflection of light rays on the inner boundary wall is a first total internal reflection angle; when the medium in contact with the inner boundary surface is entirely liquid, the critical angle for total internal reflection of light rays on the inner boundary wall is a second total internal reflection angle; and one of the preset emission angles (α) is between the first total internal reflection angle and the second total internal reflection angle.

3. The detection device as claimed in claim 1, comprising a cover that encloses the light generator and the light receiver within the cover.

4. The detection device as claimed in claim 1, wherein the light-transmitting element is a viewing glass.

5. The detection device as claimed in claim 1, wherein the light-transmitting element is part of the tube wall, or is disposed on a connecting tube protruding outward from the tube wall.

6. A refrigeration system comprising: a compressor, a condenser, a throttling device, and an evaporator, wherein the compressor, the condenser, the throttling device, and the evaporator are sequentially connected via a conduit to form a main circulation loop, the main circulation loop being configured to guide a medium therein; wherein the refrigeration system (190) further comprises: a detection device as claimed in any one of claims 1 to 5, wherein the detection device is disposed on the conduit between an outlet of the evaporator and a suction port of the compressor, and the detection device includes a light-transmitting element, a light generator configured to emit emitted light, and a light receiver configured to receive reflected light via the light-transmitting element; a controller communicatively connected to the detection device, wherein the controller is configured to perform the following processing: The light generator is controlled to emit the emitted light toward the light-transmitting element at a preset emission angle (α); and based on the intensity of the emitted light emitted by the light generator and the intensity of the reflected light received by the light receiver, the liquid content in the medium between the outlet of the evaporator and the suction port of the compressor is determined.

7. The refrigeration system of claim 6, wherein the controller is communicatively connected to the throttling device, and the control system is configured to adjust one opening degree of the throttling device based on the liquid content of the medium.

8. The refrigeration system of claim 7, wherein the refrigeration system has an operating mode and an adjustment mode, the controller being configured to control the detection device to detect the liquid content of the medium during the operating mode of the refrigeration system, and the controller being configured to perform the following processes: when the detected liquid content of the medium is not greater than a predetermined liquid content threshold, maintaining the operation of the refrigeration system in the operating mode; and when the detected liquid content of the medium is greater than the predetermined liquid content threshold, switching the operation of the refrigeration system from the operating mode to the adjustment mode.

9. The refrigeration system of claim 8, wherein in the adjustment mode, the controller is configured to perform the following processes: determine whether the suction pressure of one of the compressors has reached a minimum suction pressure threshold; when the suction pressure of the compressor reaches the minimum suction pressure threshold, reduce the load of one of the compressors; and when the suction pressure of the compressor does not reach the minimum suction pressure threshold, reduce the opening of the throttling device.

10. The refrigeration system of claim 6, wherein the controller is configured to determine the liquid content in the medium based on a ratio of the intensity of the emitted light emitted by the light generator to the intensity of the reflected light received by the light receiver.

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