Cyclone type oil separator

Abstract

The utility model relates to a whirlwind type oil separator which comprises a cylinder body, an air inlet pipe, an air outlet pipe, an upper partition plate and a lower partition plate, the upper partition plate and the lower partition plate are arranged in the cylinder body, the upper partition plate divides the interior of the cylinder body into a diffusion section and an oil subsection, and the diffusion section on the upper portion is communicated with the oil subsection on the lower portion through an air rising pipe. The lower partition plate divides the oil section into an upper separation section and a lower oil groove section, the air inlet pipe is communicated with the separation section, the air outlet pipe is communicated with the diffusion section, and the diffusion section is provided with diffusion blades. On the premise that the oil separation efficiency is guaranteed, the pressure loss of cyclone type oil separation is reduced by recovering dynamic pressure, and then the pressure ratio of a compressor is reduced, so that the energy efficiency of a refrigerating system is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of vapor compression refrigeration equipment, in particular to a cyclone oil separator used for compressor exhaust. Background Art

[0002] When operating, vapor compressors with oil lubrication systems (especially oil-injected screw compressors) inevitably carry lubricating oil in their exhaust. If this oil enters with the refrigerant vapor and remains in the condenser and evaporator, it can affect heat exchange efficiency, thereby degrading overall unit performance. Furthermore, if large amounts of lubricating oil enter the system with the refrigerant, it can cause insufficient oil supply to the compressor, affecting normal operation and even damaging it. Therefore, oil-injected compressors generally require an oil separator to separate the oil from the refrigerant and return it to the compressor.

[0003] The operating principle of a cyclonic oil separator is that the centrifugal force acting on the fluid within a rotating flow field causes oil droplets with a greater density than the refrigerant gas to move outward toward the separator wall, where they then move downward along the wall to the oil sump. Cyclonic oil separators feature a simple structure, no moving parts, low cost, and high separation efficiency. They are particularly suitable for applications with high temperatures, high pressures, and high inlet oil concentrations, and are increasingly used in HVAC screw units. Refrigerant gas is discharged from the top of the cyclonic separator along the central axis, achieving gas-oil separation. To ensure efficient operation of the cyclonic oil separator and the cleanest possible separation of oil droplets, the tangential velocity of the refrigerant gas within the cylinder is typically very high. The high-speed, rotating gas flow stores a significant amount of energy in the form of dynamic pressure. As the gas flows within the cylinder, friction with the cylinder wall results in some mechanical energy loss. This tangential velocity component is dissipated in the riser and downstream piping or flow channels, accounting for up to 80% of the total loss. This results in a greater pressure drop in traditional cyclone oil separators than gravity-sedimentation and wire mesh pad collision oil separators. (Tests show that under nominal operating conditions for screw compressors using R134a and POE synthetic oils, the pressure drop in cyclone oil separators ranges from 30 to 80 kPa, while the pressure drop in collision oil separators is generally below 10 kPa.) Traditional cyclone oil separators, such as those in patents CN205066270U, CN205027012U, and CN206944543U, focus solely on improving oil separation efficiency without considering the pressure loss associated with this oil return method, resulting in reduced refrigeration system energy efficiency. Utility Model Content

[0004] The purpose of the present utility model is to overcome the above-mentioned shortcomings and provide a cyclone oil separator, which reduces system losses and improves the operating efficiency of the whole machine while ensuring high oil separation efficiency by setting a diffuser section to recover the kinetic energy of the gas vortex in the oil separator.

[0005] The purpose of this utility model is achieved in this way:

[0006] A cyclone oil separator comprises a cylinder, an air inlet pipe, an air outlet pipe, an upper baffle and a lower baffle. The upper baffle and the lower baffle are provided in the cylinder. The upper baffle seals and separates the cylinder into a diffuser section and an oil section. The upper diffuser section and the lower oil section are connected via a riser pipe. The lower baffle further divides the oil section into an upper separation section and a lower oil tank section. The lower baffle has the function of cutting off the tail end of the cyclone and connecting to the oil tank section, thereby reducing secondary entrainment and reducing wear of the cyclone on the inner wall of the cylinder. The air inlet pipe is connected to the separation section; the air outlet pipe is connected to the diffuser section; and the diffuser section is provided with diffuser blades.

[0007] The air inlet pipe and the air outlet pipe are annular volutes; or the air inlet pipe and the air outlet pipe are both straight pipes, and the inner walls of the air inlet pipe and the air outlet pipe are tangent to the cylinder wall, so as to reduce the local pressure loss at the transition position between the air inlet pipe and the cylinder.

[0008] Preferably, the air inlet pipe is provided with a bell mouth, which has the function of rectifying the inlet fluid; the air outlet pipe is provided with a bell mouth, which has the function of finally further recovering the dynamic pressure.

[0009] Preferably, the riser is welded to the upper baffle, and a conical bell mouth is provided on the top of the riser, which has the function of initially recovering dynamic pressure; the wall thickness of the riser inlet is provided with a circular chamfer to reduce local pressure loss.

[0010] Preferably, the separation section is further provided with a bleaching liquid skirt, and the bleaching liquid skirt is arranged outside the riser.

[0011] Preferably, the float skirt is a conical structure welded to the bottom of the riser, and the edge of the float skirt is provided with serrations, which have the function of cutting off the oil film and reducing the adhesion of oil droplets to the float skirt.

[0012] Preferably, the bleaching liquid skirt is in a straight cylindrical shape and is welded to the upper partition or to the inner wall of the cylinder.

[0013] Preferably, the plurality of diffuser blades are distributed in an expansion manner, and the diffuser blades are mounted on the top cover plate of the cylinder to form a vane diffuser.

[0014] Preferably, there is a gap between the lower partition and the inner wall of the cylinder, so that the separated oil flow can enter the oil tank section to reduce secondary entrainment.

[0015] The beneficial effects of the utility model are:

[0016] Under the premise of ensuring the efficiency of oil separation, the pressure loss of cyclonic oil separation is reduced by recovering the dynamic pressure (tests show that the utility model can recover 50~80% of the dynamic pressure), thereby reducing the compressor pressure ratio and improving the energy efficiency of the refrigeration system.

[0017] A float skirt is set in the oil separation section to prevent the creeping leakage of oil droplets and make the oil separation performance more stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the appearance and structure of a cyclone oil separator according to Example 1 of the present utility model.

[0019] Figure 2 This is a schematic diagram of the internal structure of Example 1 of the present utility model (the bleaching liquid skirt has a conical structure).

[0020] Figure 3 This is a schematic diagram of the internal structure of Example 1 of the present utility model (the bleaching liquid skirt is in a straight cylindrical shape and is welded to the upper partition).

[0021] Figure 4 This is a schematic diagram of the internal structure of Example 1 of the present utility model (the bleaching liquid skirt is in a straight cylindrical shape and welded to the cylinder wall).

[0022] Figure 5 for Figure 2 AA cross-sectional view.

[0023] Figure 6 for Figure 2 BB cross-sectional view.

[0024] Figure 7-10 Top view of lower partitions with different structures.

[0025] Figure 11 This is a schematic diagram of the appearance and structure of a cyclone oil separator according to Example 2 of the present utility model.

[0026] in:

[0027] Cylinder body 1; straight cylinder 1.1; top cover plate 1.2; bottom cover plate 1.3; air inlet pipe 2; air outlet pipe 3; upper baffle plate 4; lower baffle plate 5; diffuser section 6; riser 7; conical bell mouth 7.1; separation section 8; oil tank section 9; oil outlet 10; float skirt 11; diffuser blades 12. DETAILED DESCRIPTION Example 1

[0028] See also Figure 1-10The utility model relates to a cyclone oil separator, including a cylinder 1, an air inlet pipe 2, an air outlet pipe 3, an upper baffle 4 and a lower baffle 5. The cylinder 1 is composed of a straight cylinder 1.1, a top cover plate 1.2 and a bottom cover plate 1.3. The top of the straight cylinder 1.1 is provided with a top cover plate 1.2, and the bottom is provided with a bottom cover plate 1.3. An upper baffle 4 and a lower baffle 5 are provided in the cylinder 1. The upper baffle 4 divides the cylinder into a diffuser section 6 and an oil section. The upper diffuser section 6 and the lower oil section are connected through an air riser 7. The lower baffle 5 divides the oil section into an upper separation section 8 and a lower oil tank section 9. The air inlet pipe 2 is connected to the separation section 8, and the air outlet pipe 2 is connected to the diffuser section 6. The air inlet pipe 2 and the air outlet pipe 3 are annular volutes. The annular volute-shaped air inlet pipe can widen the gas flow channel, reduce the flow velocity of the gas after flowing into the cylinder, and thus reduce the pressure drop. The annular volute-shaped outlet pipe enhances pressure diffusion and recovers more pressure energy. The riser pipe 7 is welded to the upper baffle 4 and features a tapered bellmouth 7.1 at its top. This forms a flow channel, guiding the gas from axial flow to radial flow, slowly changing the gas flow rate and reducing pressure losses directly impacting the top cover plate 1.2, thereby initially recovering dynamic pressure. The bottom of the cylinder 1 features an oil outlet 10, located near the bottom cover plate 1.3.

[0029] The separation section 8 is also provided with a bleaching liquid skirt 11 to prevent the oil droplets from creeping and leaking into the riser pipe. The bleaching liquid skirt 11 is sleeved outside the riser pipe 7. Figure 2 The float skirt 11 is a conical structure welded to the bottom of the riser 7; the edge of the float skirt is provided with serrations, which can promote the shedding of the liquid film and prevent oil droplets from adhering to the riser and affecting the oil separation efficiency.

[0030] The bleaching liquid skirt 11 is welded on the upper partition plate 4 in a straight cylindrical shape (such as Figure 3 ) or welded to the inner wall of the cylinder (such as Figure 4 ), the pressure inside cylinder 1 is higher near the cylinder wall, while the pressure in the center is lower, resulting in a large pressure gradient. Without a float skirt, some separated oil droplets may creep along the lower surface of the upper baffle and the outer wall of the riser, causing "leakage" into the riser and affecting oil separation efficiency. Adding a float skirt prevents this creeping leakage under various operating conditions and loads, resulting in more stable oil separation performance.

[0031] The diffuser section 6 is provided with diffuser blades 12, which are distributed in an expansion pattern. The diffuser blades 12 are mounted on the top cover plate 1.1 to form a vaned diffuser, which can improve the efficiency of the diffuser at the rated operating point. The diffuser blades can be straight-walled or airfoil-shaped.

[0032] There is a gap between the lower baffle 5 and the inner wall of the cylinder 1, which allows the separated oil flow to pass along the edge of the cylinder wall, preventing the tail end of the swirl from entraining the separated oil droplets and avoiding the influence of the tail end of the swirl on the oil surface and oil level in the oil tank. The lower baffle can be square (such as Figure 7 ), annular (such as Figure 8 ), round (such as Figure 9 ) and petal-shaped (e.g. Figure 10 ) etc. Figure 7 and Figure 10 , when the lower partition 5 is in contact with the cylinder 1, the lower partition is welded and fixed to the cylinder wall; Figure 8 and Figure 9 When the lower partition 5 is not in contact with the cylinder 1, the bottom of the lower partition is connected to the support plate, which has the function of preventing vortexes and is fixed to the bottom of the cylinder through the support plate. Example 2

[0033] like Figure 11 The air inlet pipe 2 and the air outlet pipe 3 are both straight pipes, and the inner walls of the air inlet pipe 2 and the air outlet pipe 3 are tangent to the cylinder wall. The rest of the structure is the same as that of Example 1.

[0034] In addition to the above embodiments, the present invention also includes other implementation methods. Any technical solutions formed by equivalent transformation or equivalent replacement should fall within the scope of protection of the claims of the present invention.

Claims

1. A cyclone oil separator, characterized in that: The cylinder comprises a cylinder, an air inlet pipe, an air outlet pipe, an upper baffle and a lower baffle. The upper baffle and the lower baffle are provided in the cylinder. The upper baffle divides the cylinder into a diffuser section and an oil section. The upper diffuser section and the lower oil section are connected through an air riser. The lower baffle divides the oil section into an upper separation section and a lower oil tank section. The air inlet pipe is connected to the separation section, and the air outlet pipe is connected to the diffuser section. The diffuser section is provided with diffuser blades. The air inlet pipe and the air outlet pipe are annular volutes, or the air inlet pipe and the air outlet pipe are straight pipes, and the air inlet pipe and the air outlet pipe are tangent to the cylinder wall.

2. A cyclone oil separator according to claim 1, characterized in that: The riser is welded on the upper baffle, and a conical bell mouth is provided on the top of the riser.

3. The cyclone oil separator according to claim 1, characterized in that: The separation section is further provided with a bleaching liquid skirt, and the bleaching liquid skirt is arranged outside the riser.

4. A cyclone oil separator according to claim 3, characterized in that: The float liquid skirt is in a conical structure and is welded to the bottom of the riser pipe. The edge of the float liquid skirt is provided with saw teeth.

5. The cyclone oil separator according to claim 3, characterized in that: The bleaching liquid skirt is in a straight cylindrical shape and is welded on the upper partition plate or on the inner wall of the cylinder.

6. The cyclone oil separator according to claim 1, characterized in that: A plurality of diffuser blades are distributed in an expansion manner and are mounted on the top cover plate of the cylinder to form a vane diffuser.

7. The cyclone oil separator according to claim 1, characterized in that: There is a gap between the lower partition and the inner wall of the cylinder.

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