Compressor built-in oil separator and low-back-pressure compressor comprising same

Abstract

The invention provides a compressor built-in oil separator and a low-backpressure compressor comprising the same. The oil separator comprises an impeller, an oil filter and a short shaft part used for penetrating through a crankshaft between a pump body assembly of the compressor and a lower shell cover, and the oil filter is arranged on the side, facing the lower shell cover, of the impeller; the impeller comprises an annular upper cover plate, an annular lower cover plate and a plurality of blades arranged between the upper cover plate and the lower cover plate; the blades extend from the inner diameter to the outer diameter of the annular upper cover plate. Comprising the built-in oil separator, a low-pressure cavity and a high-pressure cavity are formed in the upper portion and the lower portion of a lower cylinder cover respectively, after low-pressure gas is compressed in a cylinder, high-pressure refrigerant gas is discharged into a silencer below through an exhaust port of the lower cylinder cover, high-pressure gas discharged from the lower silencer enters the built-in oil separator, and the high-pressure refrigerant gas enters the built-in oil separator. The oil separator adopts a double structure of the centrifugal impeller and the oil filter to perform centrifugal separation on a high-pressure oil liquid mixture, so that the problem that lubricating oil supply and oil return of the low-pressure cavity compressor are difficult is effectively solved.

Description

Technical Field

[0001] The present invention relates to the technical field of compressors, and more particularly to an in - compressor oil separator and a low back - pressure compressor including the same. Background Art

[0002] For traditional vapor compression refrigeration compressors, we generally classify them into two structures: high - pressure chamber and low - pressure chamber according to the pressure of the refrigerant in the housing. Generally, rolling piston compressors adopt the high - pressure chamber structure. The low - pressure refrigerant gas directly enters the compressor cylinder through the suction port for compression. The high - pressure refrigerant is discharged from the cylinder and then discharged from the compressor through the exhaust pipe after entering the housing. The inside of the housing is at high pressure. For the internal lubricating oil circulation system of the high - pressure chamber compressor (the circulation of lubricating oil in the compressor housing), based on the pressure difference, the lubricating oil realizes oil pumping and lubrication of moving parts through the oil holes on the crankshaft. For the external lubricating oil circulation system (the circulation of lubricating oil in the system), most of the lubricating oil will deposit and directly return to the internal oil sump when passing through the motor and the upper housing cavity. However, due to the high exhaust temperature of the high - pressure chamber compressor, lubricating oil is likely to be discharged from the compressor with the refrigerant under large - displacement compressors or large - flow conditions, entering the system condenser and evaporator, resulting in a decrease in the system heat transfer capacity and energy efficiency. In severe cases, the compressor may fail due to lack of internal oil, poor lubrication, etc. Generally, an external oil separator is used for oil - gas separation, and the separated lubricating oil then returns to the compressor for internal circulation.

[0003] A low - pressure chamber compressor refers to a compressor with low - pressure gas inside the housing. The low - pressure refrigerant first enters the housing through the suction pipe, and then enters the cylinder through the cylinder suction port and is compressed into high - pressure gas and then discharged from the compressor. Although the low - pressure chamber compressor has advantages in terms of low refrigerant charge and low housing pressure resistance requirements, it causes difficulties in the lubricating oil supply and oil return systems for the compressor pump body structure. How to supply oil under pressure difference for the low - pressure chamber compressor and how to return the high - pressure lubricating oil in the oil separator to the low - pressure chamber oil sump without deteriorating performance are currently the difficulties in the development of low - pressure chamber compressors.

[0004] It should be noted that the information disclosed in the above background art section is only used to enhance the understanding of the background of the present invention, and thus may include information that does not constitute the prior art known to those skilled in the art. Summary of the Invention

[0005] Aiming at the problems in the prior art, the purpose of the present invention is to provide an in - compressor oil separator and a low - back - pressure compressor including the same, which can effectively solve the problems of difficult oil supply and oil return for low - pressure chamber compressors.

[0006] The first aspect of the present invention provides a compressor-integrated oil separator, which includes an impeller and an oil filter, and is used for the short shaft portion of the crankshaft passing through the pump body assembly of the compressor and the lower housing cover. The oil filter is arranged on one side of the impeller facing the lower housing cover.

[0007] The impeller includes an annular upper cover plate, an annular lower cover plate, and a plurality of blades arranged between the upper cover plate and the lower cover plate;

[0008] The blades extend from the inner diameter to the outer diameter of the annular upper cover plate.

[0009] According to the first aspect of the present invention, the difference between the outer diameter and the inner diameter of the upper cover plate is 20 mm to 50 mm.

[0010] According to the first aspect of the present invention, the upper cover plate and / or the lower cover plate is an annular flat disk or an annular curved disk.

[0011] According to the first aspect of the present invention, the blades are in a straight strip shape or an arc strip shape; and / or

[0012] The blades are not perpendicular to the upper cover plate.

[0013] According to the first aspect of the present invention, the oil filter is in an annular flat disk shape; or

[0014] The oil filter is in an annular bowl shape, and the large opening of the bowl shape faces the impeller.

[0015] According to the first aspect of the present invention, part or all of the oil filter is a filter mesh structure.

[0016] The second aspect of the present invention provides a low back-pressure compressor, including the compressor-integrated oil separator, and the lower cover plate is fixed to the short shaft portion of the crankshaft between the pump body assembly of the compressor and the lower housing cover.

[0017] According to the second aspect of the present invention, the clearance width between the outer edge of the lower cover plate and the inner wall of the compressor housing is 1 mm to 4 mm.

[0018] According to the second aspect of the present invention, the difference between the inner diameter of the upper cover plate and the outer diameter of the short shaft portion of the crankshaft is 10 mm to 30 mm.

[0019] According to the second aspect of the present invention, the pump body assembly further includes a lower cylinder head and a lower muffler arranged on the side of the lower cylinder head facing away from the cylinder, and the lower muffler is provided with a flanging structure.

[0020] In a low-backpressure compressor incorporating the oil separator built into the compressor of the present invention, the lower cylinder head divides the interior of the compressor housing into two different pressure chambers. The upper part of the lower cylinder head is the low-pressure chamber, and the lower part of the lower cylinder head is the high-pressure chamber. After the low-pressure gas is compressed in the cylinder, the high-pressure refrigerant gas is discharged into the muffler below through the exhaust port of the lower cylinder head. The high-pressure gas discharged from the lower muffler enters the built-in oil separator. The oil separator adopts a dual structure of a centrifugal impeller and an oil filter to centrifugally separate the high-pressure oil-liquid mixture. The separated refrigerant gas is discharged from the compressor through the exhaust port of the compressor. The separated lubricating oil is thrown onto the housing wall along the lower cover plate of the impeller of the oil separator and flows along the housing wall to the bottom oil sump. The filter screen structure below the impeller can perform secondary separation of the lubricating oil and at the same time prevent the oil surface from splashing in the lower oil sump caused by the agitation of the crankshaft. Since the lower part of the housing is a high-pressure chamber, the lubricating oil in the lower oil sump can be transmitted to each lubrication-required part through the crankshaft oil hole by the pressure difference. The oil separator built into the compressor of the present invention effectively solves the common problems of difficult lubrication oil supply and oil return in low-pressure chamber compressors. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings herein are incorporated into and form a part of this specification, showing embodiments consistent with the present application and, together with the specification, are used to explain the principles of the present application. By reading the detailed description of the non-limiting embodiments with reference to the following drawings, other features, objects, and advantages of the present invention will become more apparent. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts. In addition, the drawings are only schematic diagrams of the present disclosure and are not necessarily drawn to scale. The same reference numerals in the drawings represent the same or similar parts, and thus their repeated description will be omitted. Some of the block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities.

[0022] Figure 1 and Figure 2 are respectively a partial structural schematic diagram and a sectional view of a low-backpressure compressor incorporating the oil separator built into the compressor according to an embodiment of the present invention;

[0023] Figures 3 to 7 is a structural schematic diagram of an impeller according to different embodiments of the present invention;

[0024] Figures 8 to 11 is a structural schematic diagram of an oil filter according to different embodiments of the present invention; and

[0025] Figure 12 is a structural schematic diagram of a lower muffler according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in various forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of example embodiments to those skilled in the art. The features, structures, or characteristics described may be combined in any suitable manner in one or more embodiments.

[0027] In the description of this specification, the representation of reference terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. means that the specific features, structures, materials, or characteristics represented in connection with the embodiment or example are included in at least one embodiment or example of this specification. Moreover, the specific features, structures, materials, or characteristics represented can be combined in any suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples represented in this specification and the features of different embodiments or examples.

[0028] Throughout the specification, when it is said that a device is "connected" to another device, this includes not only the case of "direct connection", but also the case of "indirect connection" in which other elements are placed in between. Relative space terms such as "front", "rear", "upper", "lower", etc. may be used to more easily explain the relationship of one device relative to another device illustrated in the drawings. Such terms refer to not only the meaning indicated in the drawings, but also other meanings or operations of the device in use. For example, if the device in the drawing is flipped, a device that was previously described as "under" another device would be described as "above" the other device. Therefore, the exemplary term "lower" includes both above and below. The device can be rotated 90° or other angles, and the relative space terms are also interpreted accordingly.

[0029] Although in some instances the terms first, second, etc. are used herein to denote various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first interface and a second interface, etc. are indicated. Furthermore, as used herein, the singular forms "a", "an", and "the" are also intended to include the plural forms unless the context clearly dictates otherwise. It should be further understood that the terms "comprising", "including" indicate the presence of the stated features, steps, operations, elements, components, items, kinds, and / or groups, but do not preclude the presence, occurrence, or addition of one or more other features, steps, operations, elements, components, items, kinds, and / or groups. The terms "or" and "and / or" used herein are to be construed as inclusive, or meaning any one or any combination. Thus, "A, B, or C" or "A, B, and / or C" means "any of the following: A; B; C; A and B; A and C; B and C; A, B, and C". An exception to this definition only occurs when the combination of elements, functions, steps, or operations are inherently mutually exclusive in some manner.

[0030] Although not fully defined, including technical and scientific terms used herein, all terms shall have the same meaning as commonly understood by one of ordinary skill in the art to which this specification pertains. Terms defined in commonly used dictionaries are further interpreted to have a meaning consistent with the relevant technical literature and the content presented herein. As long as they are not defined, they shall not be over-interpreted as ideal or overly formulaic meanings.

[0031] The present invention provides an oil separator built into a compressor and a low-backpressure compressor including the same. The oil separator includes an impeller and an oil filter, and is used for a short shaft portion of a crankshaft passing through a pump body assembly of the compressor and a lower housing cover. The oil filter is disposed on a side of the impeller facing the lower housing cover; the impeller includes an annular upper cover plate, an annular lower cover plate, and a plurality of blades disposed between the upper cover plate and the lower cover plate; the blades extend from an inner diameter to an outer diameter of the annular upper cover plate.

[0032] In a low-backpressure compressor including the built-in oil separator of the present invention, the lower cylinder head divides the interior of the compressor housing into two different pressure chambers. The upper part of the lower cylinder head is the low-pressure chamber, and the lower part of the lower cylinder head is the high-pressure chamber. After the low-pressure gas is compressed in the cylinder, the high-pressure refrigerant gas is discharged into the muffler below it through the exhaust port of the lower cylinder head. The high-pressure gas discharged from the lower muffler enters the built-in oil separator. The oil separator adopts a dual structure of a centrifugal impeller and an oil filter to centrifugally separate the high-pressure oil-liquid mixture. The separated refrigerant gas is discharged from the compressor through the exhaust port of the compressor. The separated lubricating oil is thrown onto the housing wall along the impeller lower shroud of the oil separator and flows to the bottom oil sump along the housing wall. The filter screen structure below the impeller can perform secondary separation of the lubricating oil and at the same time prevent the oil surface in the lower oil sump from splashing due to the agitation of the crankshaft; because the lower part of the housing is a high-pressure chamber, the lubricating oil in the lower oil sump can be transmitted to each lubrication-required part through the crankshaft oil hole due to the pressure difference. The built-in oil separator of the compressor of the present invention effectively solves the problems of oil supply and oil return of the low-pressure chamber compressor.

[0033] The following further elaborates on the structure of the built-in oil separator of the compressor of the present invention and the low-backpressure compressor including it in conjunction with the accompanying drawings and specific embodiments. It can be understood that each specific embodiment does not limit the protection scope of the present invention.

[0034] Figure 1 and Figure 2 are respectively a partial structural schematic diagram and a sectional view of a low-backpressure compressor including the built-in oil separator of the compressor of the present invention. Among them, the built-in oil separator of the compressor includes an impeller and an oil filter, and a short shaft portion of a crankshaft 9 for passing through between the pump body assembly of the compressor and the lower housing cover. The pump body assembly generally includes an upper cylinder head, a cylinder, and a lower cylinder head, as well as an upper muffler provided on the upper cylinder head and a lower muffler provided on the lower cylinder head, etc. Of course, the pump body assembly here can also be that of a multi-cylinder compressor. For example, if it is the pump body assembly of a double-cylinder compressor, at this time, the pump body assembly includes an upper cylinder head, an upper cylinder, an intermediate plate, a lower cylinder, and a lower cylinder head, etc. The oil filter 4 is disposed on one side of the impeller facing the lower housing cover; the impeller includes an annular upper cover plate 31, an annular lower cover plate 32, and a plurality of blades 33 disposed between the upper cover plate 31 and the lower cover plate 32; the blades 33 extend from the inner diameter to the outer diameter of the annular upper cover plate 31.

[0035] More specifically, Figures 3 to 7 Schematic diagrams of the structures of the impellers of different embodiments of the present invention, Figure 3In the embodiment, the blades 33a of the impeller 3a are straight strips. Six blades 33a are evenly distributed along the circumference of the upper cover plate 31, and the blades 33a are perpendicular to the upper cover plate 31. The blades 33b / 33c of the impeller 3b / 3c can also be arc-shaped strips. Similarly, the blades 33b / 33c are evenly distributed along the circumference of the upper cover plate 31, and the blades 33b / 33c are perpendicular to the upper cover plate 31. From a top view perspective, the arc can be counterclockwise (see Figure 4 shown), or clockwise (see Figure 5 shown).

[0036] Whether it is a straight blade or an arc-shaped blade, the blades 33e of the impeller 3e may not be perpendicular to the upper cover plate 31. Figure 6 FIG. shows a schematic diagram of a straight blade 33e not perpendicular to the upper cover plate 31. It should be noted that the present invention does not limit the number of blades.

[0037] In Figures 3 to 6 the embodiment, both the upper cover plate and the lower cover plate are annular flat disks, and the upper cover plate 31 is perpendicular to its central axis, and the lower cover plate 32 is perpendicular to its central axis. In some other embodiments, the upper cover plate may not be perpendicular to its central axis; the lower cover plate may also not be perpendicular to its central axis.

[0038] In addition, both the upper cover plate and the lower cover plate can also be annular curved disks. As Figure 7 shown, the lower cover plate 32e is a curved disk. The curved disk can have a certain guiding effect on the separated lubricating oil, so that the lubricating oil can be better concentrated and thrown onto the shell wall. At this time, the interface of the blade 33e is trapezoidal instead of rectangular. Similarly, the upper cover plate can adopt a similar curved disk structure, which will not be elaborated here.

[0039] When the impeller of the present invention is applied to a compressor, it is fixedly connected to the short shaft part of the crankshaft through the lower cover plate. The rotation of the crankshaft drives the rotation of the impeller. While ensuring the oil separation efficiency, the impeller also needs to minimize the head as much as possible to avoid the impeller occupying too much energy and reducing the energy efficiency of the compressor. Therefore, the impeller must be designed according to different situations, and the angle and shape of the impeller can be adjusted. For example, the difference between the outer diameter and the inner diameter of the upper cover plate 31 can be 20 mm to 50 mm, that is, the width of the ring of the upper cover plate is between 20 mm and 50 mm. The blades can extend along the entire circumference of the upper cover plate 31 or be shorter than the outer edge of the upper cover plate 31.

[0040] Figures 8 to 11 Schematic diagrams of the oil filters in different embodiments of the present invention. The oil filter 4 is in the shape of an annular flat disk, and part or all of the oil filter is a filter mesh structure. An avoidance hole for the oil suction pipe 91 can be designed at the center of the oil filter, as Figure 8As shown, except for the holes in the oil filter 4a that avoid the suction oil pipe 91, the rest can all be filter meshes. Figure 9 For the oil filter 4b of the embodiment of Figure 9 , the outer ring is a filter mesh and the inner ring is an iron plate. At this time, the inner ring iron plate plays a role in isolating the splashing of the oil surface, and the outer ring filter mesh plays a role in separating oil and gas; the oil filter 4c can also be as Figure 10 shown, with the inner ring being a filter mesh and the outer ring being an iron plate.

[0041] To improve the separation efficiency, the oil filter 4d can also be processed into an annular "bowl-shaped" structure, with the large opening of the bowl facing the impeller, as shown in Figure 11 . The "bowl-shaped" structure guides the oil-liquid mixture flowing down along the interior of the housing to perform secondary separation on the filter mesh structure. At the same time, it can also block the splashing oil mist in the gap between the housing wall and the outer diameter of the lower cover plate of the impeller.

[0042] The oil filter has the functions of secondary separation and preventing the splash of the refrigerant oil in the oil sump at the bottom of the housing. The oil filter 4 is located below the impeller and can be fixed to the inner wall of the compressor housing by spot welding. When the refrigerant flows out from the air duct formed by the blades of the impeller, it obtains a relatively large flow velocity. At this time, a small part of the refrigerant oil may be stirred up and form fast-flowing small oil droplets. These oil droplets will enter the entire air-conditioning circulation system together with the refrigerant gas, increasing the oil output rate of the compressor. Therefore, adding an oil filter below the impeller can perform secondary separation to avoid the occurrence of the above situation.

[0043] The lower cover plate 32 of the built-in oil separator of the compressor of the present invention is fixed to the short shaft portion of the crankshaft between the pump body assembly of the compressor and the lower housing cover, that is, the inner diameter of the lower cover plate 32 is equal to the outer diameter of the short shaft portion of the crankshaft. At this time, the lower cover plate 32 can be sleeved on the short shaft portion of the crankshaft 9 and form a fixed connection therewith, so that the impeller can rotate at the same angular velocity as the crankshaft. The difference between the inner diameter of the upper cover plate 31 and the outer diameter of the short shaft portion of the crankshaft 9 is preferably between 10 mm and 30 mm. The inner diameter of the upper cover plate 31 is larger than the outer diameter of the short shaft portion of the crankshaft 9, which can enable the refrigerant to flow into the interior of the impeller from the gap between the inner diameter of the upper cover plate 31 and the outer diameter of the short shaft portion.

[0044] At the same time, the width of the gap between the outer edge of the lower cover plate 32 and the inner wall of the compressor housing 8 is 1 mm to 4 mm. The gap between the lower cover plate 32 of the impeller and the inner wall of the housing can enable the oil on the inner wall of the housing to flow smoothly to the bottom of the housing due to gravity. However, to a certain extent, it restricts the flow velocity of the refrigerant below the lower cover plate, preventing the fast-flowing refrigerant from accelerating the evaporation rate of the refrigerant oil at the bottom, and at the same time, it can further prevent the splash of the refrigerant oil in the oil sump at the bottom of the housing caused by the rotation of the crankshaft 9 sucking oil and disturbing the oil sump.

[0045] In an embodiment where the pump body assembly includes a lower cylinder head and a lower muffler disposed on a side of the lower cylinder head away from the cylinder, the lower muffler 2 is disposed between the lower cylinder head and the impeller. The lower muffler 2 may be provided with a flanging structure 21, and the outer diameter of the flanging structure 21 is less than or equal to the inner diameter of the upper cover plate 31. Figure 12 Schematic structural diagram of the lower muffler according to an embodiment of the present invention. After the low-pressure gas is compressed in the cylinder, the high-pressure refrigerant gas is discharged from the exhaust port 11 of the lower cylinder head 1 into its lower muffler 2. The flanging structure 21 of the lower muffler 2 makes it easier for the high-pressure refrigerant gas to enter the built-in oil separator, that is, it makes it easier for the oil and the refrigerant to flow into the center of the impeller.

[0046] The built-in oil separator of the present invention effectively solves the problems of difficult oil supply and oil return of the low-pressure chamber compressor. The oil holes at the upper and lower ends of the crankshaft 9 are respectively connected to the low-pressure and high-pressure chambers. The lubricating oil flows towards the low-pressure chamber through the pressure difference and lubricates the friction pairs. After entering the cylinder and returning to the bottom of the housing, under the action of the impeller, the refrigerant and the oil are separated, and the oil flows back to the bottom of the housing again to complete the oil circulation. The separated refrigerant gas is discharged from the exhaust port 81 of the compressor into the condenser.

[0047] The above content is a further detailed description of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those skilled in the art, it is obvious that this application is not limited to the details of the above exemplary embodiments, and without departing from the spirit or basic characteristics of this application, this application can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of this application is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in this application. Any reference signs in the claims should not be regarded as limiting the claimed rights.

Claims

1. An oil separator built into a compressor, characterized in that, The oil separator comprises an impeller and an oil filter, and is used to pass through the short axis portion of the crankshaft between the pump body assembly and the lower shell cover of the compressor, and the oil filter is arranged on the side of the impeller facing the lower shell cover; The impeller includes an annular upper cover plate, an annular lower cover plate and a plurality of blades arranged between the upper cover plate and the lower cover plate; The blades extend from the inner diameter to the outer diameter of the annular upper cover plate.

2. The built-in oil separator for a compressor according to claim 1, characterized in that, The difference between the outer diameter of the upper cover plate and the inner diameter of the upper cover plate is 20 mm to 50 mm.

3. The compressor-integrated oil separator according to claim 1, characterized in that, The upper cover plate and / or the lower cover plate is an annular flat disk or an annular curved disk.

4. The compressor-integrated oil separator according to claim 1, wherein, The blades are in the shape of straight strips or curved strips; and / or The blades are not perpendicular to the upper cover plate.

5. The oil separator built in the compressor according to claim 1, wherein The oil filter is in the shape of an annular flat disc; or The oil filter is in an annular bowl shape, and the large opening of the bowl faces the impeller.

6. The built-in oil separator for compressor according to claim 1, characterized in that, Part or all of the oil filter is a filter mesh structure.

7. A low back-pressure compressor, characterized in that, The invention comprises a compressor built-in oil separator as claimed in any one of claims 1 to 6, wherein the lower cover plate is fixed to the short axis portion of the crankshaft between the pump body assembly and the lower shell cover of the compressor.

8. The low back-pressure compressor according to claim 7, characterized in that, The width of the gap between the outer edge of the lower cover plate and the inner wall of the compressor shell is 1 mm to 4 mm.

9. The low back pressure compressor according to claim 7, characterized in that, The difference between the inner diameter of the upper cover plate and the outer diameter of the short shaft portion of the crankshaft is 10 mm to 30 mm.

10. The low back-pressure compressor according to claim 8, characterized in that, The pump body assembly also includes a lower cylinder cover and a lower muffler arranged on a side of the lower cylinder cover away from the cylinder, and the lower muffler is provided with a flange structure.

Images