A return oil nozzle with a guiding structure

Abstract

This utility model discloses a return oil nozzle with a guiding structure, aiming to solve the problem of difficult oil return caused by low lubricating oil flow rate and insufficient pressure difference in traditional return oil pipelines. The nozzle includes a valve seat and a guide nozzle. The valve seat is installed in the compressor suction pipeline and connects the return oil pipeline between the external oil separator and the compressor suction port via an angle valve. The guide nozzle is brazed to the valve seat and inserted into the compressor suction pipeline, guiding the lubricating oil flow. The valve seat is provided with a socket welding hole and welding auxiliary positioning lines to ensure installation accuracy. The guide nozzle is made of bent copper tubing, with its centerline forming an angle with the compressor's horizontal suction port to improve flow guiding efficiency. This utility model can improve the unit's oil return capacity, prevent lubricating oil stagnation during shutdown, simplify the pipeline structure, and ensure the compressor's lubrication and cooling effects.

Description

Technical Field

[0001] This article relates to a return oil nozzle with a guiding structure. Background Technology

[0002] Evaporative screw chillers are core equipment in industrial and commercial refrigeration. The stability of their oil return system directly affects the performance of the unit. Traditional units have flawed oil return pipeline designs. When the flow rate of lubricating oil through the oil return pipeline is too low, or when the system's high and low pressure difference is insufficient, the lubricating oil cannot smoothly enter the compressor's suction port and thus remains inside the evaporator.

[0003] Residual lubricating oil forms an oil film on the surface of the evaporator heat exchange tubes, significantly reducing the effective heat transfer area. This leads to a decrease in the heat transfer coefficient and a drop in evaporation temperature, directly weakening the cooling effect. Furthermore, the lower the evaporation temperature, the more difficult it is for the system to return oil, creating a vicious cycle of "difficult oil return → poor cooling → even more difficult oil return." Simultaneously, insufficient oil in the compressor leads to poor lubrication, increased friction between moving parts, and long-term operation can cause wear and jamming of mechanical components, even leading to compressor failure, severely impacting the unit's lifespan and operational safety. Utility Model Content

[0004] In view of this, the present invention aims to propose an oil return guide nozzle for evaporative screw chillers to compensate for the design defects of the oil return pipeline of traditional evaporative screw chillers and solve the problems of poor system cooling capacity, poor compressor lubrication, and compressor damage caused by low oil return efficiency.

[0005] A return oil nozzle with a guiding structure includes: a valve seat and a guide nozzle; the guide nozzle is integrally installed on the compressor suction pipe; the valve seat is connected to the return oil pipe between an external oil separator and the compressor suction port via an angle valve; one end of the guide nozzle is fixed to the valve seat, and the other end is inserted into the compressor suction pipe; the guide nozzle is generally arc-shaped, with the inlet end embedded in the valve seat and the outlet end located inside the compressor suction pipe, and the centerline of the outlet end forms an angle α with the axis of the compressor suction port, wherein the angle α satisfies the requirement that rays along the outlet end can penetrate into the compressor suction port. This effectively guides the lubricating oil entering the compressor suction port through the return oil pipe.

[0006] Among them, the arc-shaped structure can reduce the frictional resistance of lubricating oil during the flow process and avoid turbulence caused by pipeline bends; the design of angle α can make the lubricating oil sprayed in a precise direction, ensuring that it enters the compressor suction port directly and avoids stagnation on the inner wall of the suction pipeline, solving the problem of low oil return efficiency caused by directional deviation in traditional oil return pipelines. At the same time, through the integrated installation of valve seat and guide nozzle, an efficient oil return path is formed from oil separator to compressor, improving the stability of system oil return.

[0007] Furthermore, the valve seat has a socket welding hole inside and welding auxiliary positioning lines on its outer surface; the guide nozzle is positioned for insertion depth through the socket welding hole and fixed to the valve seat by brazing. The guide nozzle is positioned for insertion depth through a stepped hole inside the valve seat, brazed onto the valve seat, and the valve seat is positioned for installation insertion depth of the return oil guide nozzle on the compressor suction line by the welding auxiliary positioning lines on its surface.

[0008] Furthermore, the valve seat is made of thickened carbon steel, and the guide nozzle is formed by bending a copper tube.

[0009] The guide nozzle is installed on the valve seat and adopts a fusion-shaped design concept. After the oil return guide nozzle is installed, it guides the low-speed lubricating oil entering the compressor suction line, which improves the oil return capacity during the operation of the evaporative screw chiller unit. It also prevents the lubricating oil entering the compressor suction line from failing to return to the compressor due to the low pressure difference when the unit is shut down. At the same time, the fusion-shaped design allows the appearance of the traditional valve seat to be retained, simplifying the internal piping structure of the unit.

[0010] Furthermore, the angle α ranges from 0° to 10°. This angle range can match the airflow direction at the compressor intake port, which is typically horizontal or slightly inclined, so that the lubricating oil injection direction forms a forward angle with the airflow at the intake port, avoiding turbulence caused by the oil flow and airflow colliding and reducing energy loss. This angle range is particularly suitable for low flow rate conditions, and can guide the lubricating oil to smoothly enter the intake port with the airflow through directional flow guidance, improving the reliability of oil return under low pressure differential.

[0011] Furthermore, the air inlet end of the guide nozzle and the socket welding hole of the valve seat are interference fit. The interference fit can pre-fix the guide nozzle and the valve seat before welding, prevent positional displacement caused by vibration or collision during assembly, and ensure the accuracy of angle α and insertion depth.

[0012] Furthermore, the socket welding hole of the valve seat has a stepped hole structure, including a guide section, a positioning section, and a welding section. The guide section guides the gas flow; the positioning section precisely limits the insertion depth of the nozzle through the stepped surface, ensuring that the position of its outlet end in the intake pipe meets the design requirements; the welding section provides sufficient space for brazing, facilitating uniform filling of the solder, enhancing the welding strength, and at the same time, the stepped structure can disperse stress, avoid interface cracking caused by thermal expansion and contraction after welding, and improve the overall durability of the structure.

[0013] Furthermore, the outlet port of the guide nozzle is chamfered. The chamfer eliminates the sharp edge of the outlet, preventing lubricating oil from forming eddies or stagnating at the port and reducing local flow resistance.

[0014] Furthermore, the valve seat is connected to the compressor suction line using argon arc welding. Argon arc welding produces a high-strength weld that can withstand vibrations and system pressure during unit operation, preventing loosening of the connection. Simultaneously, argon arc welding has a small heat-affected zone, reducing deformation of the suction line and valve seat and ensuring the installation accuracy of the guide nozzle.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. Improved oil return capability: The directional flow guidance of the guide nozzle can effectively accelerate the flow of low-speed lubricating oil. Even if the system pressure difference is low, it can push the lubricating oil into the compressor suction port, solving the traditional problem of difficult oil return. 2. Avoiding oil stagnation during shutdown: When the unit is shut down, the system pressure difference drops significantly, and lubricating oil tends to stagnate in traditional pipelines. However, the flow guiding structure of this nozzle can help the lubricating oil overcome the resistance of low pressure difference and flow back to the compressor smoothly. 3. Streamlined Piping Structure: The integrated design eliminates the need for additional guide pipes in the traditional oil return system. While retaining the appearance of the traditional valve seat, it reduces the number of pipe connection points, lowers the risk of leakage, and facilitates the internal space layout of the unit. IV. Ensuring Unit Performance: Through efficient oil return, the formation of an oil film on the evaporator is avoided, maintaining the evaporator's heat transfer efficiency and cooling effect. At the same time, it ensures sufficient lubrication of the compressor, reduces mechanical wear, and extends the unit's service life. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall installation of the return oil guide nozzle; Figure 2 This is a partial installation diagram of the return oil guide nozzle on the compressor suction line; Figure 3 This is a schematic diagram of the internal structure of the return oil guide nozzle; In the diagram: 1-valve seat, 2-guide nozzle, 3-compressor suction line, 4-oil return line, 5-compressor suction port, 6-external oil separator, 7-angle valve. Detailed Implementation

[0017] To enhance understanding of this utility model, the present utility model will be further described in detail below with reference to the embodiments and accompanying drawings. These embodiments are only used to explain the present utility model and do not constitute a limitation on the scope of protection of the present utility model.

[0018] Example 1: As Figures 1 to 3As shown, a return oil guide nozzle includes a valve seat 1 and a guide nozzle 2. The guide nozzle 2 is positioned at its insertion depth through a stepped hole inside the valve seat 1 and is brazed onto the valve seat 1. The valve seat 1 uses mounting positioning lines on its surface to position the insertion depth of the return oil guide nozzle on the compressor suction line 3. The valve seat 1 connects to the return oil line 4 between an external oil separator 6 and the compressor suction port 5 via an angle valve 7. The guide nozzle is inserted into the compressor suction line 3 to guide the lubricating oil entering the compressor suction port 5 through the return oil line 4. In this embodiment, the centerline of the guide nozzle forms a 2° angle with the compressor suction port.

[0019] Work process When the unit is running, the lubricating oil separated by the external oil separator 6 flows into the angle valve 7 through the return oil pipeline 4. After the angle valve 7 adjusts the flow rate of the lubricating oil, the lubricating oil enters the valve seat 1. Under the directional flow guidance of the guide nozzle 2, the lubricating oil accelerates into the compressor suction pipeline 3 along the inclined direction of the nozzle, and enters the compressor suction port 5 along with the refrigerant flow, completing the oil return. When the unit is stopped, the system pressure difference decreases. In traditional pipelines, the lubricating oil is prone to stagnation due to gravity. However, the inclined structure of the guide nozzle 2 can help the lubricating oil overcome resistance and slowly flow into the suction pipeline along the inner wall of the nozzle, and finally return to the compressor, avoiding stagnation.

[0020] In this embodiment, the valve seat 1, made of thickened carbon steel, can withstand system pressures of over 1.6 MPa; the guide nozzle 2, formed from copper tubing, is resistant to low-temperature corrosion and is suitable for the unit's working environment from -20°C to 50°C; the welding auxiliary positioning line ensures that the installation error is ≤2 mm, avoiding flow failure caused by installation deviation; the 15°-30° included angle design can increase the lubricating oil flow rate by 30%-50%, and the oil return efficiency is significantly better than that of traditional pipelines.

[0021] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model and are not intended to limit it. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this utility model without departing from the spirit and scope of the technical solutions of this utility model, and all such modifications or substitutions should be covered within the scope of the claims of this utility model.

Claims

1. A return oil nozzle with a guiding structure, characterized in that, include: Valve seat (1) and guide nozzle (2); the guide nozzle (2) is installed on the compressor suction pipe (3); the valve seat (1) is connected to the return oil pipe (4) between the external oil separator (6) and the compressor suction port (5) through the angle valve (7); one end of the guide nozzle (2) is fixed to the valve seat (1), and the other end is inserted into the compressor suction pipe (3); the guide nozzle (2) is arc-shaped, the inlet end is embedded in the valve seat (1), the outlet end is set inside the compressor suction pipe (3), and the center line of the outlet end is at an angle α with the axis of the compressor suction port (5), the angle α is such that the ray along the outlet end can enter the compressor suction port (5).

2. A return oil nozzle with a guiding structure according to claim 1, characterized in that, The valve seat (1) has a socket welding hole inside and a welding auxiliary positioning line on its outer surface; the guide nozzle (2) is positioned at the insertion depth through the socket welding hole and is fixed to the valve seat (1) by brazing.

3. A return oil nozzle with a guiding structure according to claim 2, characterized in that, The valve seat (1) is made of thickened carbon steel, and the guide nozzle (2) is formed by bending a copper tube.

4. A return oil nozzle with a guiding structure according to claim 2, characterized in that, The angle α ranges from 0° to 10°.

5. A return oil nozzle with a guiding structure according to claim 4, characterized in that, The air inlet end of the guide nozzle (2) and the socket welding hole of the valve seat (1) are interference fit.

6. A return oil nozzle with a guiding structure according to claim 4, characterized in that, The valve seat (1) has a stepped hole structure for the socket welding hole, which includes a guide section, a positioning section and a welding section.

7. A return oil nozzle with a guiding structure according to claim 4, characterized in that, The outlet port of the guide nozzle (2) is chamfered.

8. A return oil nozzle with a guiding structure according to claim 4, characterized in that, The valve seat (1) is connected to the compressor suction pipe (3) by argon arc welding.

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