Oil separation device and water heater

Abstract

This invention discloses an oil separation device and a water heater. The oil separation device includes: a shell with a refrigerant inlet for a heat exchange system at the upper part and a refrigerant outlet and an oil outlet at the lower part; and a filter and cooling assembly disposed within the shell, separating the upper and lower parts of the shell, for filtering and cooling the refrigerant passing through the heat exchange system. The oil separation device of this invention performs both oil separation and cooling within the shell, and recovers waste condensate through the heat exchange section, driving the cooling refrigerant to continuously circulate in the pipeline, forming a closed loop of "heat exchange section - cooling pipes - heat exchange section". This allows the oil separation device to utilize the waste condensate from the chassis to reduce exhaust temperature and improve oil return efficiency. Furthermore, it can be used as an electric heating element in low ambient temperatures to prevent chassis icing by utilizing the exhaust temperature.

Description

Technical Field

[0001] This utility model relates to the field of water heater technology, specifically to an oil separator and a water heater. Background Technology

[0002] Heat pump water heaters, as efficient and environmentally friendly hot water supply equipment, are widely used in modern homes and commercial spaces. Driven by the pursuit of high performance and low cost in heat pump water heaters, rotary compressors have become the preferred choice due to their performance-to-price ratio. However, with the increasing market demand for large-capacity models, the issues of oil return and high exhaust temperatures in rotary compressors have become more prominent during the development of such models, becoming key problems affecting equipment quality.

[0003] Oil return issues primarily manifest as the failure of lubricating oil to effectively return to the compressor during refrigerant circulation, leading to insufficient lubrication inside the compressor and potentially causing wear or overheating malfunctions. High exhaust temperature issues, on the other hand, refer to excessively high exhaust temperatures during compressor operation. This not only reduces the system's energy efficiency ratio but can also damage internal compressor components and even pose potential safety hazards. These problems are particularly pronounced in high-capacity compressors because they require higher refrigerant flow rates and greater compression capabilities, making oil return and high exhaust temperature issues more difficult to control.

[0004] In the development of high-capacity heat pump water heaters, traditional solutions, while alleviating the problems of high oil return and exhaust temperatures to some extent, lead to increased costs and extended development cycles, limiting equipment performance optimization and market competitiveness. Therefore, it is urgent to explore new technologies or methods to effectively solve the oil return and exhaust temperature problems of rotary compressors in high-capacity models without significantly increasing costs and complexity, thereby improving the overall performance and reliability of heat pump water heaters. Utility Model Content

[0005] In order to solve the technical problem of high exhaust temperature in the existing large-capacity heat pump water heater, this utility model proposes an oil separation device and a water heater.

[0006] The technical solution adopted in this utility model is:

[0007] This utility model proposes an oil separation device, comprising:

[0008] The housing has a refrigerant inlet for the heat exchange system at the upper part and a refrigerant outlet and an oil outlet for the heat exchange system at the lower part.

[0009] A filter cooling assembly is disposed within the housing, separating the upper and lower parts of the housing, and is used to filter and cool the refrigerant passing through the heat exchange system.

[0010] Specifically, the filtration and cooling assembly includes: a filter screen that prevents the refrigerant from undergoing oil separation, and a cooling assembly that cools the area around the filter screen.

[0011] Furthermore, the cooling components include:

[0012] A cooling pipe is provided, which surrounds the filter screen and is located between the inner wall of the housing and the filter screen, and a cooling refrigerant is provided inside the cooling pipe;

[0013] The heat exchange section is installed on the chassis through which the condensate flows in the heat exchange system;

[0014] The refrigerant circulation pipe assembly is connected to the inlet and outlet of the cooling pipe fittings and the inlet and outlet of the heat exchange section, so that the cooling refrigerant circulates between the cooling pipe fittings and the heat exchange section.

[0015] Furthermore, the refrigerant circulation pipe assembly is equipped with a one-way valve that creates a pressure difference to circulate the cooling refrigerant and a shut-off valve that switches off the refrigerant circulation pipe assembly.

[0016] Furthermore, the filter screen is provided with multiple layers of spacing.

[0017] This utility model also proposes a water heater, including the aforementioned oil separation device.

[0018] The water heater includes: a compressor, a four-way valve, a vapor-liquid separator, an oil separation device, a first heat exchanger, a throttle valve, and a second heat exchanger; the exhaust side of the compressor is connected to the refrigerant inlet of the oil separation device, the refrigerant outlet of the oil separation device is connected to the port D of the four-way valve, the port C of the four-way valve, the first heat exchanger, the throttle valve, the second heat exchanger, and the port E of the four-way valve are connected in sequence, the port S of the four-way valve, the vapor-liquid separator, and the suction side of the compressor are connected in sequence, and the oil outlet of the oil separation device is connected to the vapor-liquid separator.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] This oil separator performs both oil separation and cooling within the casing, and recovers waste condensate through a heat exchange section to drive the cooling medium in continuous circulation within the pipeline, forming a closed loop of "heat exchange section - cooling pipes - heat exchange section". This allows the oil separator to utilize the waste condensate from the chassis to reduce exhaust temperature and improve oil return efficiency. Furthermore, it can function as an electric heating element in low ambient temperatures, using exhaust temperature to prevent chassis icing. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the shell structure according to an embodiment of the present invention;

[0023] Figure 2 This is a top view of the interior of the housing in an embodiment of this utility model;

[0024] Figure 3 This is a bottom view of the interior of the housing in an embodiment of this utility model;

[0025] Figure 4 This is a schematic diagram of the structure of the oil separation device of this utility model;

[0026] Figure 5 This is a simplified top view of the chassis structure of this utility model;

[0027] Figure 6 This is a system connection diagram of the water heater of this utility model;

[0028] Figure 7 This is a system connection diagram of the cooling mode of the hot water system of this utility model;

[0029] Figure 8 This is a system connection diagram of the heating mode of the hot water mechanism of this utility model;

[0030] 1. Oil separation device;

[0031] 11. Shell;

[0032] 111. Refrigerant inlet; 112. Refrigerant outlet; 113. Oil outlet;

[0033] 121. Filter screen; 122. Cooling pipe fittings; 123. Heat exchange section; 124. Refrigerant circulation pipe assembly; 125. Check valve; 126. Shut-off valve;

[0034] 2. Compressor;

[0035] 21. Exhaust temperature sensing bulb;

[0036] 3. Four-way valve;

[0037] 4. Vapor-liquid separator;

[0038] 5. First heat exchanger;

[0039] 6. Throttling valve;

[0040] 7. Second heat exchanger;

[0041] 8. Liquid storage tank;

[0042] 9. Chassis. Detailed Implementation

[0043] To make the technical problems, technical solutions, and beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0044] The principle and structure of this utility model will be described in detail below with reference to the accompanying drawings and embodiments.

[0045] In the development of large-capacity heat pump water heaters, traditional solutions can alleviate the problems of high-temperature oil return and exhaust to some extent, but the resulting increase in costs and extended development cycles limit the performance optimization and market competitiveness of the equipment.

[0046] In this regard, such as Figure 1 , 6 As shown, this utility model proposes an oil separation device 1, mainly used in heat exchange systems such as water heaters, including: a shell 11 and a filter cooling assembly. Specifically, the shell 11 can be cylindrical (or rectangular), with a refrigerant inlet 111 at the top for connecting to the heat exchange system, and a refrigerant outlet 112 at the bottom connected to the heat exchange system, as well as a separate oil outlet 113. The cylindrical shell 11 design facilitates a stable flow path for the refrigerant inside, while also providing standardized installation space for the filter cooling assembly.

[0047] The filtration and cooling assembly is located inside the housing 11, dividing the interior of the housing 11 into two independent chambers, upper and lower, by means of horizontal or inclined methods. This assembly can both intercept oil droplets carried in the refrigerant using a filter structure and cool the refrigerant through built-in cooling pipes or heat sinks. After the refrigerant enters from the upper inlet of the housing 11, it needs to undergo filtration and cooling processes by the filtration and cooling assembly, and finally returns to the heat exchange system from the lower refrigerant outlet 112; while the separated oil is deposited at the bottom of the housing 11 under gravity or centrifugal force and discharged through the oil outlet 113.

[0048] This device combines the layout of the refrigerant inlet 111, outlet and filter cooling components, so that the refrigerant can complete the dual treatment of oil separation and cooling in the shell 11 of the oil separator, which improves the oil separation efficiency and reduces the exhaust temperature. It is suitable for large-capacity heat pump water heaters. Moreover, the independently set oil outlet 113 ensures efficient discharge of oil and prevents it from mixing into the refrigerant circulation system.

[0049] like Figure 2 , 3 As shown in Figure 4, in a specific embodiment, the filter cooling assembly specifically includes a filter screen 121 and a cooling assembly. The filter screen 121 adopts a multi-layer mesh structure, and its surface can be treated with an oleophobic coating to effectively intercept oil droplets in the refrigerant. The mesh has a tapered, tapered design, which minimizes the resistance to refrigerant flow and prevents oil droplets from accumulating and clogging the pores.

[0050] The cooling components are arranged around the filter 121 in the form of aluminum heat sink fins or circulating cooling pipes (the distance ΔH between the outer edge of the filter and the inner wall of the housing can be 1 cm or other reasonable values), reducing the temperature of the filtration area through liquid cooling. When the refrigerant flows through the filter 121, the cooling components simultaneously remove heat from the refrigerant and oil mixture, causing the refrigerant temperature to drop, prompting more oil vapor to condense into liquid oil droplets and be captured by the filter 121, while also reducing the exhaust temperature of the compressor 2.

[0051] By integrating filtration and cooling functions into the same component, this design achieves a dual improvement in oil separation efficiency and refrigerant exhaust temperature control while ensuring refrigerant flow stability.

[0052] In a further embodiment, the cooling assembly specifically includes: a cooling pipe 122, a heat exchange section 123, and a refrigerant circulation pipe assembly 124; the cooling pipe 122 has a spiral or annular pipe structure and is arranged tightly against the inner wall of the housing 11 along the outer periphery of the filter screen 121. Figure 5 As shown, the heat exchange unit 123 is integrated inside the chassis 9 on the condensate side (the left side is the condensate side, and the right side is the compressor side) of the heat exchange system, and exchanges heat directly with the condensate through a serpentine coil or finned plate heat exchanger. This design can recover and reuse the residual cooling of the condensate, reducing additional energy consumption.

[0053] The refrigerant circulation pipe assembly 124 has its circulation inlet and outlet pipes connected to the inlet and outlet of the cooling pipe fitting 122 and the inlet and outlet of the heat exchange section 123 via flanges or quick couplings, which enables the refrigerant to circulate between the cooling pipe fitting 122 and the heat exchange section 123 to deliver cooling capacity.

[0054] This cycle recovers waste condensate through heat exchanger 123, driving the refrigerant to circulate continuously in the pipeline, forming a closed loop of "heat exchanger 123 - cooling pipe 122 - heat exchanger 123". This ensures that the filter area 121 maintains a certain cooling intensity, improving the unit's energy efficiency. The refrigerant circulation can be driven by a micro centrifugal pump or refrigerant pressure differential, reducing the need for additional power components.

[0055] Furthermore, the refrigerant circulation pipe assembly 124 also includes a one-way valve 125 and a shut-off valve 126: The one-way valve 125 is installed at the outlet end of the main circulation pipe of the refrigerant circulation pipe assembly 124, and achieves one-way flow through a spring-loaded valve core or a gravity-loaded ball structure, ensuring that the cooling refrigerant circulates only in the direction of "heat exchange section 123 → cooling pipe 122 → heat exchange section 123", preventing a decrease in heat exchange efficiency caused by backflow. The shut-off valve 126 is installed on the circulation inlet or outlet pipe of the refrigerant circulation pipe assembly 124, and can completely block the flow of refrigerant when the valve is closed.

[0056] Through the coordinated operation of the check valve 125 and the shut-off valve 126, the system ensures both the directional stability of the refrigerant circulation and provides the operator with flexible control over the circulation path. The differential pressure opening and closing mechanism of the check valve 125 reduces the external power requirement, while the shut-off function of the shut-off valve 126 enhances the equipment control interface, facilitating the control of exhaust temperature as needed and the compensation of chassis temperature in low-temperature environments.

[0057] In a specific embodiment, the filter screen 121 is arranged in multiple layers with alternating vertical spacing. Preferably, the filter screen 121 has two layers along the refrigerant flow direction. Through the synergistic effect of multi-layer filtration structure for graded interception and gravity sedimentation, the oil separation efficiency is further improved.

[0058] In a preferred embodiment, the mesh diameter of each layer decreases sequentially, forming a gradually denser interception structure. Adjacent layers maintain a distance to provide a buffer space for the gravity settling of oil droplets in the refrigerant. The edge of the bottom filter 121 extends downwards to form an oil-guiding ramp, guiding the separated oil droplets to flow directionally towards the bottom of the housing 11.

[0059] In a specific embodiment, the refrigerant inlet 111 is located at the top center of the housing 11. The refrigerant impacts the first-layer filter 121 in a downward spiral path, and large oil droplets are pre-attached and intercepted through inertial separation. The refrigerant outlet 112 is located at the bottom of the housing 11, maintaining a certain horizontal distance from the oil outlet 113. The oil outlet 113 is adjacent to the lowest point of the outer wall at the bottom of the housing 11, and in conjunction with the internal conical guide groove, uses gravity to allow the oil to flow out by gravity, avoiding mixing with the rising refrigerant airflow.

[0060] like Figure 6 As shown, this utility model also proposes a water heater using the aforementioned oil separator. The oil separator 1 is installed in the pipeline between the compressor 2's exhaust port and the condenser inlet. Its cylindrical shell 11 is directly connected to the system pipeline via a flange. The refrigerant inlet 111 connects to the high-temperature, high-pressure exhaust of the compressor 2. After being cooled by multiple layers of filtration inside the device, the refrigerant enters the condenser through the bottom refrigerant outlet 112. The separated lubricating oil flows back to the compressor 2's lubrication system through the bottom oil outlet 113 of the shell 11, forming a closed loop. This effectively reduces the compressor 2's exhaust temperature and improves oil return efficiency.

[0061] The circulation system of the hot water heater includes: compressor 2, four-way valve 3, vapor-liquid separator 4, oil separator 1, first heat exchanger 5, throttle valve 6, liquid storage tank 8, and second heat exchanger 7; wherein,

[0062] Compressor 2, as the power core, has its exhaust side directly connected to the refrigerant inlet 111 at the top of oil separator 1, ensuring that high-temperature, high-pressure refrigerant vapor first enters oil separator 1. The refrigerant outlet 112 of oil separator 1 is connected to the port D of four-way valve 3 via a high-pressure pipeline. This valve serves as a system mode switching hub, achieving bidirectional cooling / heating circulation by changing the position of its internal slider. The exhaust side of compressor 2 is connected to the refrigerant inlet 111 of oil separator 1, and the refrigerant outlet 112 of oil separator 1 is connected to the port D of four-way valve 3. The port C of four-way valve 3, the first heat exchanger 5, the throttle valve 6, the liquid receiver 8, the second heat exchanger 7, and the port E of four-way valve 3 are sequentially connected. The port S of four-way valve 3, the vapor-liquid separator 4, and the suction side of compressor 2 are sequentially connected. The oil outlet 113 of oil separator 1 is connected to the vapor-liquid separator 4.

[0063] like Figure 7 As shown, in cooling mode: the refrigerant flows from port D of the four-way valve 3 to port C, enters the first heat exchanger 5 (condenser) to release heat, then passes through the throttling valve 6 to reduce pressure and throttle, then flows through the second heat exchanger 7 (evaporator) to absorb heat from the water source, and finally returns from port E of the four-way valve 3 to port S. After passing through the vapor-liquid separator 4 to remove any possible entrained liquid refrigerant, it enters the suction side of the compressor 2 to complete the cycle.

[0064] like Figure 8 As shown, in heating mode: the slider of the four-way valve 3 switches the path, and the refrigerant flows from interface D through interface E to the second heat exchanger 7 (which acts as a condenser at this time), releasing heat to heat the domestic water. Then the flow reverses, passing through the throttle valve 6 and the first heat exchanger 5 (evaporator), and finally returns to the compressor 2 from interface C. The oil outlet 113 of the oil separator 1 is directly connected to the vapor-liquid separator 4 through an oil guide pipe. The separated lubricating oil continuously flows back to the suction side of the compressor 2 under the action of gravity and pressure difference, forming a closed lubrication cycle. This design avoids the accumulation of lubricating oil in the system pipeline. At the same time, the vapor-liquid separator 4 performs secondary dust removal and droplet interception on the return gas, ensuring the long-term stable operation of the compressor 2.

[0065] This system enhances oil return efficiency and effectively reduces exhaust problems through an oil separation device, while also improving equipment reliability and energy utilization.

[0066] This utility model also proposes a water heater control method, which, using the above-mentioned water heater, includes the following steps:

[0067] During operation, the hot water system continuously monitors the real-time operating frequency of the compressor. This frequency threshold (e.g., 35Hz) is preset based on the compressor's rated power and system load characteristics. When the compressor frequency is detected to be lower than the preset frequency (e.g., due to low temperature environment or low heat load), the controller triggers the shut-off valve of the oil separator to open, or keeps it in the open state.

[0068] After the shut-off valve opens, the cooling refrigerant in the refrigerant circulation pipe assembly continues to flow, maintaining the stability of the low-temperature field in the filter zone and reducing the exhaust temperature to match the compressor's operating frequency. Simultaneously, the continuous operation of the cooling components creates a directional temperature gradient, accelerating the condensation and sedimentation of tiny oil droplets in the refrigerant.

[0069] Furthermore, when the ambient temperature is higher than a third preset temperature (e.g., 0°C), the controller continuously records the cumulative opening time of the shut-off valve. When the first preset time (e.g., 30 minutes) is reached, it automatically switches to a periodic on / off control mode. The specific execution logic is as follows:

[0070] The preset switching cycle is 15 minutes, of which the shut-off valve is open for 10 minutes and closed for 6 minutes.

[0071] This control strategy utilizes the residual cooling of chassis condensate periodically, ensuring oil separation efficiency while avoiding waste of cooling capacity. It is suitable for regions with hot summers and warm winters, ensuring full, cascaded utilization of residual cooling from condensate in high-temperature environments and reducing additional cooling energy consumption.

[0072] Specifically, the system is equipped with an exhaust temperature sensor at the compressor exhaust port to monitor the refrigerant discharge temperature in real time; a first preset temperature (e.g., 100°C) and a second preset temperature (e.g., 90°C) are set as the critical thresholds for cooling enhancement and cooling shutdown, respectively.

[0073] It also includes the following steps:

[0074] When the sensor detects that the exhaust temperature exceeds the first preset temperature, the controller triggers the shut-off valve to open or maintains its open state. At this time, the refrigerant circulation pipe assembly starts, and the cooling refrigerant circulates between the heat exchange section and the cooling pipes, quickly absorbing the heat of the high-temperature refrigerant through the coil structure, while enhancing the cooling intensity of the filter area.

[0075] When the exhaust temperature drops below the second preset temperature, the controller closes the shut-off valve or keeps it closed to stop the circulation of the cooling refrigerant.

[0076] This temperature-linked control strategy can absorb the heat of the high-temperature refrigerant through the coil structure of the cooling pipes when the exhaust temperature is high, and enhance the cooling intensity of the filter area to increase oil return. When the exhaust temperature is normal, the shut-off valve is closed to avoid affecting the exhaust temperature.

[0077] Specifically, the control method of the water heater also includes the following steps: when the ambient temperature is detected to be lower than the third preset temperature (such as 0°C), the low temperature protection timer is started to accumulate the duration of low temperature (the first preset duration can be set to 30 minutes).

[0078] During the timing process, if the shut-off valve is detected to open due to other conditions (such as low frequency or high temperature of the compressor), the current accumulated time is immediately reset to zero to avoid conflicts between multiple control commands and ensure the priority of the low temperature protection logic.

[0079] When the low temperature duration reaches the first preset duration (30 minutes), the controller forcibly opens the shut-off valve and keeps it open for a second preset duration (e.g., 10 minutes). During this stage, the refrigerant circulation pipe assembly is forced to operate.

[0080] This control strategy solves the problem of chassis with condensate easily freezing in extremely low temperature environments (below -10℃). In other words, the heat exchange unit essentially functions as the electric heating belt originally installed on the chassis. By frequently heating the chassis in low temperature environments, ice accumulation is avoided, and the fan blades of the heat exchanger are prevented from hitting the ice on the chassis.

[0081] It should be noted that the terminology used above is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this utility model. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0082] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0083] In the description of this utility model, it should be understood that the directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this utility model. The directional terms "inner" and "outer" refer to the inner and outer contours of each component itself.

[0084] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0085] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be construed as limiting the scope of protection of this utility model.

[0086] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. An oil separation device, characterized by include: The housing has a refrigerant inlet for the heat exchange system at the upper part and a refrigerant outlet and an oil outlet for the heat exchange system at the lower part. A filter cooling assembly is disposed within the housing, separating the upper and lower parts of the housing, and is used to filter and cool the refrigerant passing through the heat exchange system.

2. The oil separation device as described in claim 1, characterized in that, The filtration and cooling assembly includes: a filter screen that prevents the refrigerant from undergoing oil separation, and a cooling assembly that cools the area around the filter screen.

3. The oil separation device as described in claim 2, characterized in that, The cooling assembly includes: A cooling pipe is provided, which surrounds the filter screen and is located between the inner wall of the housing and the filter screen, and a cooling refrigerant is provided inside the cooling pipe; The heat exchange section is installed on the chassis through which the condensate flows in the heat exchange system; The refrigerant circulation pipe assembly is connected to the inlet and outlet of the cooling pipe fittings and the inlet and outlet of the heat exchange section, so that the cooling refrigerant circulates between the cooling pipe fittings and the heat exchange section.

4. The oil separation device as described in claim 3, characterized in that, The refrigerant circulation pipe assembly is equipped with a one-way valve that creates a pressure difference to circulate the cooling refrigerant and a shut-off valve that switches off the refrigerant circulation pipe assembly.

5. The oil separation device as described in claim 2, characterized in that, The filter screen is spaced in multiple layers.

6. A water heater, characterized in that, Includes the oil separation device as described in any one of claims 1 to 5.

7. The water heater as described in claim 6, characterized in that, The water heater includes: a compressor, a four-way valve, a vapor-liquid separator, an oil separator, a first heat exchanger, a throttle valve, and a second heat exchanger; the exhaust side of the compressor is connected to the refrigerant inlet of the oil separator, the refrigerant outlet of the oil separator is connected to the port D of the four-way valve, the port C of the four-way valve, the first heat exchanger, the throttle valve, the second heat exchanger, and the port E of the four-way valve are connected in sequence, the port S of the four-way valve, the vapor-liquid separator, and the suction side of the compressor are connected in sequence, and the oil outlet of the oil separator is connected to the vapor-liquid separator.

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