CN114320923A

CN114320923A - Scroll compressor with oiling system

Info

Publication number: CN114320923A
Application number: CN202110957496.1A
Authority: CN
Inventors: 帕特利斯·博尼弗尔; 布瑞安·安吉尔; 伊薇斯·罗森; 弗洛伦特·伯根; 加布里埃尔·史崔达
Original assignee: Danfoss Commercial Compressors SA
Current assignee: Danfoss Commercial Compressors SA
Priority date: 2020-09-29
Filing date: 2021-08-19
Publication date: 2022-04-12
Anticipated expiration: 2041-08-19
Also published as: DE102021119804A1; CN114320923B; FR3114623A1; FR3114623B1

Abstract

The scroll compressor (1) comprises a compression unit (6) having a plurality of compression chambers (15) and an oil injection system (33) configured to inject oil into the compression unit (6), the oil injection system (33) comprising an oil reservoir (34) having a constant oil level and provided with a calibrated oil outlet opening (36) and an oil siphon device (47) configured to receive oil flowing through the calibrated oil outlet opening (36), the oil siphon device (47) comprising a siphon flow path (48) having an inlet and an outlet, the inlet communicating with a low pressure volume of the scroll compressor (1), the outlet communicating with an inlet of the compression chambers (15), the scroll compressor (1) being configured such that a volume of refrigerant supplied to the scroll compressor (1) travels through the siphon flow path (48) before reaching the compression unit (6), and such that a volume of oil received in the oil siphon device (47) is supplied to the compression chambers by the refrigerant traveling through the siphon flow path (48) (15).

Description

Scroll compressor with oiling system

Technical Field

The present invention relates to a scroll compressor, and in particular to a scroll refrigeration compressor.

Background

Scroll compressors generally include:

-a hermetic housing provided with a suction inlet port configured to supply refrigerant to be compressed to the scroll compressor,

-a compression unit having a plurality of compression chambers and configured to compress refrigerant supplied by the suction port, and

-a drive shaft configured to drive an orbiting scroll member of the compression unit in an orbiting motion.

When such a scroll compressor is operated at low compressor speed and/or low suction pressure, the amount of oil circulating with the refrigerant in the scroll compressor and flowing to the compression unit is low and therefore the oil circulation ratio (OCR, oil circulation ratio corresponds to the ratio between the oil mass flow and the total mass flow (oil + refrigerant) in the refrigeration system) is also low. Such low oil transport may cause compressor performance problems due to poor sealing and lubrication of the compression chambers of various portions of the scroll compressor, and may result in elevated discharge temperatures because insufficient oil is delivered to the compression chambers.

When such scroll compressors operate at high compressor speeds and/or high suction pressures, OCR and the amount of oil transported by the refrigerant towards the compression unit is high. This high oil transport can lead to lubrication problems of the scroll compressors because of the excess oil delivered from the scroll compressors in the refrigeration system piping and components, due to the lack of oil in the scroll compressors, and can lead to refrigeration system performance problems because the excess oil in the refrigeration system reduces the thermal energy exchange within the heat exchanger of the refrigeration system downstream of the scroll compressors (in view of the fact that the oil droplets contained in the refrigerant have a tendency to deposit on the heat exchanger and form an oil layer on the heat exchanger).

To overcome the said drawbacks, it is known to provide scroll compressors with a specific oil injection system configured to inject oil into the compression unit.

US 8,449,276B 2 shows in particular a scroll compressor comprising a solenoid valve system connected to an oil pump and configured to control the injection of oil into the compression chamber based on the compressor speed.

A similar system is disclosed in US 9,377,013B 2, in which the solenoid valve system is replaced by a connector member and tuned fill and return lines.

US 5,174,740 shows an oil reservoir formed on the upper surface of the base plate of the fixed scroll member. The oil reservoir is intended to supply oil into the suction gas passage through a valve arrangement actuated by the difference between the suction pressure and the discharge pressure.

However, the oiling systems disclosed in the above-mentioned prior art are complex and expensive.

Disclosure of Invention

It is an object of the present invention to provide an improved scroll compressor which overcomes the disadvantages encountered in conventional scroll compressors.

It is another object of the present invention to provide a scroll compressor which allows improved control of OCR under all operating conditions at a lower cost than the prior art. This means that complex lines and valve systems, or electronic controls for injecting oil into the compression unit, are to be avoided, among other things.

According to the present invention, such a scroll compressor comprises:

a compression unit having a plurality of compression chambers and configured to compress the refrigerant supplied from the suction port,

-a drive shaft configured to drive an orbiting scroll member of the compression unit in an orbiting motion, and

-an oil injection system configured to inject oil into the compression unit, the oil injection system comprising an oil reservoir having a constant oil level and provided with a calibrated oil outlet opening, the oil injection system further comprising an oil siphon configured to receive oil flowing through the calibrated oil outlet opening, the oil siphon comprising a siphon flow path configured to receive oil supplied to the oil siphon through the calibrated oil outlet opening, the siphon flow path having an inlet in communication with a low pressure volume of the scroll compressor and an outlet in communication with an inlet of the compression chamber, the scroll compressor being configured such that at least 50%, advantageously at least 70%, of the refrigerant supplied to the scroll compressor through the suction inlet port, And, for example, at least 80%, travels through the siphon flow path before reaching the compression unit and such that all or substantially all of the oil received in the oil siphon device is supplied to the compression chamber by the refrigerant traveling through the siphon flow path.

This configuration of the oiling system provides a constant oil mass flow to the compression chamber independent of operating conditions and/or compressor speed because the oil reservoir delivers a constant oil mass flow to the oil siphon device and nearly all of the oil from the oil reservoir is delivered to the compression chamber.

This results in: at low speed/low suction pressure, relatively high OCR, ensures good compression chamber sealing; and at high speed/high suction pressure, relatively low OCR, avoids excessive oil in the refrigeration system and ensures good lubrication conditions for the scroll compressor.

Moreover, such oiling systems can be achieved with only minor modifications to existing compressor designs and few additional components, which limits the manufacturing costs of scroll compressors according to the present invention.

Thus, the oiling system according to the invention allows to provide a scroll compressor which is cheaper to manufacture, while ensuring improved control of OCR under all operating conditions.

The scroll compressor may also include one or more of the following features, either alone or in combination.

According to one embodiment of the invention, the siphon flow path comprises a siphon portion, which is U-shaped in cross-section and is configured to receive oil supplied to the oil siphon through the calibrated oil outlet opening.

According to one embodiment of the invention, the oil injection system is configured to control an amount of oil delivered to the compression chambers of the compressor.

According to one embodiment of the invention, the scroll compressor is configured such that: all of the refrigerant supplied to the scroll compressor through the suction port travels through the siphon flow path before reaching the compression unit.

According to one embodiment of the invention, the scroll compressor is configured such that: all of the oil supplied to the oil siphon through the calibrated oil outlet opening is supplied to the compression chamber by the refrigerant travelling through the siphon flow path, i.e. is transported to the compression chamber by the refrigerant travelling through the siphon flow path.

According to one embodiment of the invention, the oil reservoir is configured to collect oil supplied from an oil sump to the oil injection system during operation of the scroll compressor.

According to one embodiment of the invention, said orbiting scroll member is supported by and in sliding contact with a support means arranged inside the closed shell, said oil reservoir being defined by said support means. Advantageously, the support means is made in one piece.

According to one embodiment of the invention, the oil reservoir is formed at the bottom of the inner chamber of the support means.

According to one embodiment of the invention, said calibration oil outlet opening is present in said inner chamber of said support means.

According to one embodiment of the invention, the calibration oil outlet opening is formed directly in the bottom plate of the support device or in a separate plug element which is inserted in a hole provided in the bottom plate.

According to an embodiment of the invention, the oil injection system further comprises an oil return conduit comprising an oil inlet port and an oil outlet port, the oil inlet port being present in the oil reservoir, the oil inlet port being positioned to define the constant oil level of the oil reservoir.

According to an embodiment of the invention, the oil outlet port of the oil return conduit is fluidly connected to the oil sump and is configured to return a portion of the oil contained in the oil reservoir towards the oil sump.

According to an embodiment of the invention, the oil return duct is fixed to the support device.

According to an embodiment of the invention, the oil injection system further comprises an oil supply channel fluidly connected to an oil sump and extending over at least a portion of the length of the drive shaft, the oil supply channel being configured to supply oil from the oil sump to the oil reservoir.

According to one embodiment of the invention, the oil sump is located at the bottom of the hermetic shell.

According to an embodiment of the invention, the oil injection system further comprises an oil pump configured to supply oil from the oil sump to the oil supply channel.

According to one embodiment of the invention, the oil siphon comprises a base portion surrounding the hub portion of the support means and, for example, sealingly surrounding the hub portion of the support means.

According to one embodiment of the invention, the base portion has the shape of a plate.

According to one embodiment of the invention, the base portion comprises a lower surface abutting against the motor cover.

According to one embodiment of the invention, the scroll compressor includes an electric motor coupled to the drive shaft and configured to drive the drive shaft to rotate about an axis of rotation, the electric motor including a rotor and a stator disposed about the rotor. Advantageously, the motor cover is configured to cover the electric motor.

According to one embodiment of the invention, the stator includes a stator lamination (stack) and a stator winding wound on the stator lamination, the stator winding defining an upper stator end winding and a lower stator end winding, the motor cover being configured to cover the upper stator end winding.

According to one embodiment of the invention, said base portion further comprises a siphon chamber, which is open upwards and partially defines said siphon flow path, and advantageously said siphon chamber partially defines a lower portion of a siphon flow path, said siphon chamber being configured to receive oil supplied to said oil siphon through said calibrated oil outlet opening, and in particular to collect oil received by said siphon flow path.

According to one embodiment of the invention, the base portion further comprises a wall section over at least a part of its circumference, the wall section extending upwardly and defining the siphon chamber.

According to one embodiment of the invention, the siphon chamber is arranged in a space defined between two radially projecting portions of the support means.

According to one embodiment of the invention, the oil siphon device further comprises a siphon channel portion having a lower wall portion protruding into the siphon chamber, the siphon chamber and the siphon channel portion at least partially defining the siphon flow path.

According to one embodiment of the invention, the siphon chamber and the lower wall portion of the siphon channel portion define a siphon portion of the siphon flow path.

According to one embodiment of the present invention, the scroll compressor is configured such that the oil level in the siphon portion is maintained below the lower edge of the lower wall portion of the siphon channel portion.

According to one embodiment of the invention, the siphon channel portion is arranged in the space.

According to one embodiment of the invention, the siphon channel portion comprises a guide wall extending substantially vertically and comprising the lower wall portion and an upper wall portion, the upper wall portion partially defining the outlet of the siphon flow path.

According to an embodiment of the present invention, the siphon channel part further includes a deflection wall protruding from an outer surface of the guide wall and partially defining an inlet of the siphon flow path. Advantageously, said deflector wall has a concave lower surface.

According to one embodiment of the present invention, the siphon channel part further comprises an upper end wall extending outwardly from an upper edge of the upper wall part. Advantageously, the upper end wall extends radially with respect to the axis of rotation of the drive shaft.

According to one embodiment of the present invention, the base portion and the siphon channel portion are different and separate from each other. However, the base portion and the siphon channel portion may be made in a single piece (e.g. by 3D printing).

According to one embodiment of the present invention, the oil siphon further comprises baffle portions arranged in additional spaces formed between the radially protruding portions of the support means, each of the baffle portions extending between the support means and the hermetic shell so as to block a flow of refrigerant toward the compression chamber, such that all of the refrigerant supplied to the scroll compressor through the suction port is forced to flow through the siphon chamber.

According to one embodiment of the invention, the baffle portion is integrated into the support means and may be made in a single piece with the support means.

According to an embodiment of the invention, the oil siphon further comprises a receiving chamber configured to collect oil flowing from the oil reservoir through the calibration oil outlet opening.

According to an embodiment of the invention, the receiving chamber is provided on the base part.

According to an embodiment of the invention, the receiving chamber is located vertically below the calibration oil outlet opening.

According to an embodiment of the invention, the receiving chamber faces the calibration oil outlet opening.

According to one embodiment of the invention, the receiving chamber is upwardly open.

According to an embodiment of the invention, the oil siphon device further comprises an oil feed passage fluidly connecting the receiving chamber to the siphon chamber, the oil feed passage being configured to allow oil collected in the receiving chamber to flow into the siphon chamber.

According to an embodiment of the invention, the oil feed passage is provided on the base part.

According to one embodiment of the invention, the oil siphon further comprises a pressure balancing opening present in the receiving chamber, the pressure balancing opening being configured to ensure pressure balancing between the receiving chamber and the low pressure volume of the scroll compressor.

According to one embodiment of the invention, the pressure equalizing opening is provided on a chamber wall extending upwardly and defining the receiving chamber. Advantageously, the pressure equalization opening is provided on an upper edge of the chamber wall.

According to one embodiment of the invention, the scroll compressor is a variable speed scroll compressor or a fixed speed scroll compressor.

According to one embodiment of the invention, the support means further comprise a through hole present in the internal chamber of the support means and fluidly connecting the internal chamber to an external space defined by the support means and the hermetic shell, the through hole being configured to ensure a pressure balance between the internal chamber and the low pressure volume of the scroll compressor.

According to one embodiment of the invention, the oil siphon device comprises a plurality of siphon flow paths.

According to an embodiment of the invention, each of the siphon flow paths is configured to receive a portion of the oil flowing through the calibration oil outlet opening of the oil reservoir.

According to another embodiment of the invention, the oil reservoir is provided with a plurality of calibration oil outlet openings, each of the siphon flow paths being configured to receive oil flowing through a respective one of the calibration oil outlet openings.

According to an embodiment of the invention, the oil siphon comprises a plurality of receiving chambers, each receiving chamber being configured to collect oil flowing from the oil reservoir through a respective one of the calibration oil outlet openings.

According to another embodiment of the invention, the oil siphoning device comprises a common receiving chamber configured to collect the oil flowing from the oil reservoir through the calibration oil outlet opening.

These and other advantages will become apparent upon reading the following description, considering as a non-limiting example the attached drawings, which accompany the following description, which represent embodiments of the scroll compressor according to the present invention.

Drawings

The following detailed description of one embodiment of the invention can be best understood when read in conjunction with the accompanying drawings, which are to be understood, however, that the invention is not limited to the specific embodiments disclosed.

Fig. 1 is a longitudinal sectional view of a scroll compressor according to the present invention.

FIG. 2 is a partial perspective view of the scroll compressor of FIG. 1.

FIG. 3 is a partial perspective cross-sectional view of the scroll compressor of FIG. 1.

Fig. 4 is an enlarged view of a detail of fig. 1.

FIG. 5 is a perspective view of a base portion of the scroll compressor of FIG. 1.

Fig. 6 is a perspective view of a siphon channel part of the scroll compressor of fig. 1.

Detailed Description

FIG. 1 depicts a scroll compressor 1 occupying a vertical position in accordance with an embodiment of the present invention.

The scroll compressor 1 includes a hermetic casing 2, the hermetic casing 2 being provided with a suction port 3 and a discharge port 4, the suction port 3 being configured to supply a refrigerant to be compressed to the scroll compressor 1, and the discharge port 4 being configured to discharge the compressed refrigerant.

The scroll compressor 1 further includes a supporting device 5, the supporting device 5 being fixed to the hermetic shell 2, and a compression unit 6, the compression unit 6 being disposed inside the hermetic shell 2 and supported by the supporting device 5. The compression unit 6 is configured to compress the refrigerant supplied through the suction port 3. The compression unit 6 includes a fixed scroll 7 and an orbiting scroll 8, the fixed scroll 7 being fixed with respect to the hermetic shell 2, the orbiting scroll 8 being supported by a thrust bearing surface 9 provided on the support device 5 and being in sliding contact with the thrust bearing surface 9. According to the embodiment shown in the figures, the support means 5 are made in one piece.

The fixed scroll member 7 includes a fixed base plate 11, the fixed base plate 11 having a lower face oriented toward the orbiting scroll member 8 and an upper face opposite the lower face of the fixed base plate 11. The fixed scroll 7 further includes a fixed spiral Wrap (spiral Wrap)12, and the fixed spiral Wrap 12 projects from a lower surface of the fixed base plate 11 toward the orbiting scroll 8.

The orbiting scroll 8 comprises an orbiting base plate 13, the orbiting base plate 13 having an upper face oriented towards the fixed scroll 7 and a lower face opposite the upper face of the orbiting base plate 13 and slidably mounted on the thrust bearing surface 9. The orbiting scroll 8 further includes an orbiting spiral wrap 14, and the orbiting spiral wrap 14 protrudes from an upper face of the orbiting base plate 13 toward the fixed scroll 7. An orbiting spiral wrap 14 of the orbiting scroll 8 is engaged with a fixed spiral wrap 12 of the fixed scroll 7 to form a plurality of compression chambers 15 between the orbiting spiral wrap 14 and the fixed spiral wrap 12. Each of the compression chambers 15 has a variable volume that decreases from the outside inward when the orbiting scroll member 8 is driven to orbit relative to the fixed scroll member 7.

The scroll compressor 1 further includes an electric motor 16 disposed below the support device 5, and the electric motor 16 may be a variable speed electric motor. The electric motor 16 has a rotor 17 and a stator 18, and the stator 18 is disposed around the rotor 17. The stator 18 comprises stator laminations 19, also referred to as stator core, and stator windings wound on the stator laminations 19. The stator windings define upper stator end windings 21 formed by portions of the stator windings extending upwardly from the upper axial end face of the stator laminations 19 and lower stator end windings 22 formed by portions of the stator windings extending downwardly from the lower axial end face of the stator laminations 19.

Furthermore, the scroll compressor 1 comprises a drive shaft 23, which drive shaft 23 is vertical and rotatable about the axis of rotation a. The drive shaft 23 is coupled to the rotor 17 of the electric motor 16 such that the electric motor 16 is configured to drive the drive shaft 23 in rotation about the axis of rotation a. The drive shaft 23 is in particular configured: when the electric motor 16 is operated, the orbiting scroll 8 is driven to orbit.

The drive shaft 23 comprises a drive portion 24 at its upper end, which drive portion 24 is offset from the longitudinal axis of the drive shaft 23, and which drive portion 24 is partly mounted in an orbiting hub portion 25, which orbiting hub portion 25 is provided on the orbiting scroll member 8. The drive portion 24 is configured to: when the electric motor 16 is operated, it cooperates with the orbiting hub portion 25 to drive the orbiting scroll member 8 in an orbiting motion relative to the fixed scroll member 7.

The drive shaft 23 further includes an upper guided portion 26 and a lower guided portion 27, the upper guided portion 26 being adjacent to the drive portion 24, the lower guided portion 27 being opposite the upper guided portion 26, and the scroll compressor 1 further includes an upper main bearing 28 and a lower main bearing 29, the upper main bearing 28 being disposed on the support 5 and configured to guide the upper guided portion 26 of the drive shaft 23 for rotation, the lower main bearing 29 being configured to guide the lower guided portion 27 of the drive shaft 23 for rotation. The scroll compressor 1 further includes an orbiting scroll hub bearing 31 provided on the orbiting scroll 8, and arranged to mate with the drive portion 24 of the drive shaft 23.

The scroll compressor 1 further includes a motor cover 32, the motor cover 32 being configured to cover the upper stator end winding 21.

Further, the scroll compressor 1 includes an oil injection system 33, the oil injection system 33 being configured to inject oil into the compression unit 6.

The oiling system 33 includes an oil reservoir 34, the oil reservoir 34 having a constant oil level. Advantageously, the reservoir 34 is defined by the support means 5. The support means 5 comprises in particular an inner chamber 35, in which inner chamber 35 the drive portion 24 of the drive shaft 23 and the orbiting hub portion 25 provided on the orbiting scroll member 8 are received, and the oil reservoir 34 is formed at the bottom of the inner chamber 35. According to the embodiment shown in the figures, the oil reservoir 34 extends around the drive shaft 23.

The oil reservoir 34 is provided with a calibration oil outlet opening 36, which calibration oil outlet opening 36 emerges in the inner chamber 35 of the support device 5. According to the embodiment shown in the figures, the calibrated oil outlet opening 36 is formed in a separate plug element 37, which plug element 37 is inserted in a hole 38 provided in a bottom plate 39 of the support device 5. However, according to another embodiment of the invention, the calibration oil outlet opening 36 may be formed directly in the bottom plate 39 of the support device 5.

The oiling system 33 further includes an oil supply passage 41, and the oil supply passage 41 is formed in the drive shaft 23 and extends over the entire length of the drive shaft 23. According to the embodiment shown in the figures, this oil supply channel 41 emerges in the upper end face 42 of the drive shaft 23 oriented towards the orbiting scroll 8.

The oil supply passage 41 is configured to supply oil from an oil groove 43, the oil groove 43 being defined by the hermetic case 2, for example, at the bottom of the hermetic case 2, and the oil supply passage 41 is configured to supply oil from the oil groove 43 to the oil reservoir 34. According to an embodiment of the present invention, the oiling system 33 may include an oil pump configured to supply oil from the oil groove 43 to the oil supply passage 41.

The oil injection system 33 further comprises a return line 44, which return line 44 is fixed to the support means 5 and comprises an oil inlet port 44.1 present in the oil reservoir 34. Advantageously, the oil inlet port 44.1 is positioned vertically so as to define a maximum oil level in the oil reservoir 34 and thereby a constant oil level of the oil reservoir 34. The oil level h in the oil reservoir 34 is shown in fig. 4. The oil return conduit 44 further comprises an oil outlet port 44.2, which oil outlet port 44.2 is present outside the oil reservoir 34 and is vertically offset from said oil inlet port 44.1. The oil outlet port 44.2 is advantageously fluidly connected with the oil groove 43, and the oil outlet port 44.2 is configured to return a portion of the oil contained in the oil reservoir 34 towards the oil groove 43.

The oil injection system 33 further comprises an oil siphon 47, which oil siphon 47 is configured to receive oil flowing through the calibrated oil outlet opening 36.

The oil siphon 47 particularly comprises a siphon flow path 48, which siphon flow path 48 is configured to receive the oil supplied to the oil siphon 47 through the calibrated oil outlet opening 36. The siphon flow path 48 has an inlet 48.1 and an outlet 48.2, the inlet 48.1 communicating with the low pressure volume V of the scroll compressor 1 and the outlet 48.2 communicating with the inlet E of the compression chamber 15. Siphon flow path 48 further includes a siphon portion 48.3, siphon portion 48.3 being U-shaped in cross-section and located between inlet 48.1 and outlet 48.2. The siphon portion 48.3 is particularly configured to receive oil supplied to the oil siphon 47. The refrigerant flow F flowing through the siphon flow path 48 is schematically shown in fig. 4.

The scroll compressor 1 is particularly configured such that all or substantially all of the refrigerant supplied to the scroll compressor 1 through the suction port 3 travels through a siphon flow path 48 before reaching the compression unit 6, and such that all or substantially all of the oil received in the oil siphon 47 (via the calibrated oil outlet opening 36) is supplied to the compression chamber 15 through the refrigerant traveling through this siphon flow path 48. However, it is possible for the scroll compressor 1 to be configured such that at least 50% of the refrigerant supplied to the scroll compressor 1 through the suction port 3 travels through the siphon flow path 48 before reaching the compression unit 6, and such that all or substantially all of the oil received in the oil siphon 47 (via the calibrated oil outlet opening 36) is supplied to the compression chamber 15 through the refrigerant traveling through this siphon flow path 48.

According to the embodiment shown in the figures, the oil siphon 47 comprises a base portion 49, which base portion 49 surrounds (and for example sealingly surrounds) a hub portion 51 of the support means 5, and which base portion 49 may have a plate shape. Advantageously, the base portion 49 is located above the motor cover 32 and comprises a lower surface that rests on the motor cover 32. The lower surface of the base portion 49 may be sealed, for example, against the motor cover 32. According to the embodiment shown in the figures, a first O-ring 52 is inserted between the base portion 49 and the hub portion 51, and a second O-ring 53 is inserted between the base portion 49 and the motor cover 32.

Due to the presence of the first and second O-

rings

52, 53, ambient OCR in the scroll compressor is advantageously reduced. Furthermore, the first O-ring 52 here facilitates assembly of the scroll compressor, as the first O-ring 52 allows assembly of the base portion 49 and the support device 5 as a subassembly. Furthermore, thanks to the first and second O-

rings

52, 53, the bearing leakage flow through the upper main bearing 28 is directed to the lower region of the scroll compressor, so that the oil enters the oil groove 43 and not the compression unit 6.

The base portion 49 comprises a receiving chamber 54, which receiving chamber 54 is configured to collect oil flowing from the oil reservoir 34 through the calibration oil outlet opening 36. Advantageously, the receiving chamber 54 is open upwards and is located vertically below the calibration oil outlet opening 36. In other words, the receiving chamber 54 faces the calibration oil outlet opening 36.

The base portion 49 further includes a pressure balance opening 50, the pressure balance opening 50 being present in the receiving chamber 54 and being configured to ensure pressure balance between the receiving chamber 54 and the low pressure volume V of the scroll compressor 1. The pressure equalizing opening 50 is provided in a chamber wall 54.1, which chamber wall 54.1 extends upwardly and defines the receiving chamber 54. Advantageously, the pressure equalizing opening 50 is provided on an upper edge of the chamber wall 54.1 and defines a pressure equalizing gap between the support device 5 and the base portion 49.

The base portion 49 further includes a wall section over at least a portion of its circumference that extends upwardly and defines a siphon chamber 55, the siphon chamber 55 being open upwardly and partially defining a lower portion of the siphon flow path 48. Siphon chamber 55 is particularly configured to collect oil received by siphon flow path 48 and from oil reservoir 34. The siphon chamber 55 can be arranged in a space 56 defined between two radial projections 57 of the support means 5.

The oil siphon 47 is configured such that: if the oil level in the siphon chamber 55 increases, the refrigerant velocity above the surface of the free oil (free oil) also increases. Thus, during operation of the scroll compressor, the refrigerant velocity will particularly increase to a level large enough to carry the oil contained in the siphon chamber 55 up to the compression unit 6.

The base portion 49 also includes an oil feed passage 58, the oil feed passage 58 fluidly connecting the receiving chamber 54 to the siphon chamber 55, and the oil feed passage 58 is configured to allow oil collected in the receiving chamber 54 to flow into the siphon chamber 55. Advantageously, the oil feed passage 58 is inclined with respect to the vertical and occurs in the lower portion of the receiving chamber 54 and in the siphon chamber 55, respectively.

The oil siphon 47 further comprises a siphon channel portion 59, which siphon channel portion 59 is arranged in the space 56 and is distinct and separate from the base portion 49. The siphon channel portion 59 is advantageously fixed to the support means 5. Advantageously, siphon chamber 55 and siphon channel portion 59 at least partially define siphon flow path 48.

According to the embodiment shown in the drawings, the siphon channel portion 59 comprises a guide wall 61, the guide wall 61 extending substantially vertically and comprising a lower wall portion 62 and an upper wall portion 63, the lower wall portion 62 projecting into the siphon chamber 55, the upper wall portion 63 being located above the siphon chamber 55 and partially defining the outlet 48.2 of the siphon flow path 48. Advantageously, the siphon chamber 55 and the lower wall portion 62 of the siphon channel portion 59 define the siphon portion 48.3 of the siphon flow path 48, and the oil feed passage 58 is present in the siphon chamber 55 vertically above the lower edge of the lower wall portion 62. The scroll compressor 1 is particularly configured such that: during operation of the scroll compressor 1, the oil level in the siphon portion 48.3 is maintained below the lower edge of the lower wall portion 62. The oil siphon 47 is configured such that for all compressor speeds, the oil level within the siphon chamber 55 is maintained to ensure that: by varying the distance between the free oil surface and the lower edge of the lower wall portion 62 of the siphon channel portion 59, almost all of the oil received in the oil siphon device 47 is carried to the compression unit 6 by the refrigerant gas flow. At low compressor speeds and hence low refrigerant flow, a relatively high oil level will be maintained such that the refrigerant velocity at the lower edge of the lower wall portion 62 is sufficiently great to carry the oil contained in the siphon chamber 55 to the compression unit 6. At high compressor speeds and high refrigerant gas flows, the lower oil level in the siphon chamber 55 is sufficient to ensure that oil is carried to the compression unit 6.

Siphon channel portion 59 further includes a deflector wall 64, which deflector wall 64 projects outwardly from the outer surface of guide wall 61 and partially defines the inlet 48.1 of the siphon flow path 48. Advantageously, the deflector wall 64 has a concave lower surface.

According to the embodiment shown in the drawings, the siphon channel portion 59 further comprises an upper end wall 65, which upper end wall 65 extends outwardly from the upper edge of the guide wall 61 and blocks the flow of refrigerant towards the compression chamber 15. Advantageously, the upper end wall 65 extends radially with respect to the rotation axis a of the drive shaft 23.

The oil siphon 47 further comprises baffle portions 66, for example three baffle portions, said baffle portions 66 being arranged in additional spaces 67 formed between the radial projections 57 of the support means 5. Each of said baffle portions 66 is advantageously fixed to the support means 5. However, the baffle portion 66 and the support means 5 may also be made as a single piece.

Each of the baffle portions 66 extends between the support 5 and the hermetic shell 2 to block the flow of refrigerant toward the compression chamber 15 so that all of the refrigerant supplied to the scroll compressor 1 through the suction port 3 is forced to flow through the siphon chamber 55 before reaching the compression unit 6.

According to an embodiment of the present invention, the support means 5 may further comprise a through hole 68, the through hole 68 being present in the inner chamber 35 of the support means 5 and fluidly connecting the inner chamber 35 to an outer space 69 defined by the support means 5 and the hermetic shell 2, the through hole 68 being configured to ensure pressure equalization between the inner chamber 35 and the low pressure volume V of the scroll compressor 1.

The invention is of course not limited to the embodiments described above by way of non-limiting examples, but on the contrary encompasses all embodiments thereof.

Claims

1. A scroll compressor (1) comprising:

-a hermetic shell (2), said hermetic shell (2) being provided with a suction inlet (3), said suction inlet (3) being configured to supply the refrigerant to be compressed to the scroll compressor (1),

-a compression unit (6), the compression unit (6) having a plurality of compression chambers (15), and the compression unit (6) being configured to compress the refrigerant supplied by the suction port (3),

-a drive shaft (23), the drive shaft (23) being configured to drive an orbiting scroll member (8) of the compression unit (6) in an orbiting motion,

-a support means (5), said support means (5) being arranged inside said hermetic shell (2), said orbiting scroll (8) being supported by said support means (5) and being in sliding contact with said support means (5), and

-an oil injection system (33), the oil injection system (33) being configured to inject oil into the compression unit (6), the oil injection system (33) comprising an oil reservoir (34), the oil reservoir (34) having a constant oil level and being provided with a calibration oil outlet opening (36), the oil injection system (33) further comprising an oil siphon device (47), the oil siphon device (47) being configured to receive oil flowing through the calibration oil outlet opening (36), the oil siphon device (47) comprising a siphon flow path (48), the siphon flow path (48) being configured to receive oil supplied to the oil siphon device (47) through the calibration oil outlet opening (36), the siphon flow path (48) having an inlet (48.1) and an outlet (48.2), the inlet (48.1) being in communication with a low pressure volume (V) of the scroll compressor (1), the outlet (48.2) communicates with an inlet (E) of the compression chamber (15), the scroll compressor (1) being configured such that at least 50% of the refrigerant supplied to the scroll compressor (1) through the suction inlet (3) travels through the siphon flow path (48) before reaching the compression unit (6), and such that all or substantially all of the oil received in the oil siphon (47) is supplied to the compression chamber (15) through the refrigerant traveling through the siphon flow path (48).

2. A scroll compressor (1) as claimed in claim 1, wherein said oil reservoir (34) is defined by said support means (5).

3. A scroll compressor (1) according to claim 2, wherein the oil reservoir (34) is formed at the bottom of the internal chamber (35) of the support means (5).

4. A scroll compressor (1) according to any one of claims 1 to 3, wherein said calibrated oil outlet opening (36) is formed directly in a bottom plate (39) of said support means (5) or in a separate plug element (37), said separate plug element (37) being inserted in a hole (38) provided in said bottom plate (39).

5. A scroll compressor (1) according to any one of claims 1 to 4, wherein said oil injection system (33) further comprises an oil return conduit (44), said oil return conduit (44) comprising an oil inlet port (44.1) and an oil outlet port (44.2), said oil inlet port (44.1) being present in said oil reservoir (34), said oil inlet port (44.1) being positioned to define said constant oil level of said oil reservoir (34).

6. The scroll compressor (1) according to any one of claims 1 to 5, wherein the oil injection system (33) further comprises an oil supply channel (41), the oil supply channel (41) being fluidly connected to an oil sump (43) and extending over at least a portion of the length of the drive shaft (23), the oil supply channel (41) being configured to supply oil from the oil sump (43) to the oil reservoir (34).

7. A scroll compressor (1) as claimed in any one of claims 1 to 6, wherein the oil siphon (47) comprises a base portion (49), the base portion (49) surrounding a hub portion of the support means (5).

8. A scroll compressor (1) as claimed in claim 7, wherein the base portion (49) includes a lower surface that abuts against the motor cover (32).

9. A scroll compressor (1) as claimed in claim 7 or 8, wherein the base portion (49) further comprises a siphon chamber (55), the siphon chamber (55) being upwardly open and partially defining the siphon flow path (48), the siphon chamber (55) being configured to receive oil supplied to the oil siphon (47) through the calibrated oil outlet opening (36).

10. A scroll compressor (1) as claimed in claim 9, wherein said siphon chamber (55) is arranged in a space (56) defined between two radially projecting portions (57) of said support means (5).

11. A scroll compressor (1) according to claim 9 or 10, wherein the oil siphon device (47) further comprises a siphon channel portion (59), the siphon channel portion (59) having a lower wall portion (62) protruding into the siphon chamber (55), the siphon chamber (55) and the siphon channel portion (59) at least partially defining the siphon flow path (48).

12. Scroll compressor (1) according to any of claims 9 to 11, wherein the oil siphon (47) further comprises baffle portions (66), said baffle portions (66) being arranged in additional spaces (67) formed between the radially protruding portions (57) of the support means (5), each of said baffle portions (66) extending between the support means (5) and the hermetic shell (2) so as to block the refrigerant flow towards the compression chamber (15) such that all of the refrigerant supplied to the scroll compressor (1) through the suction inlet (3) is forced to flow through the siphon chamber (55).

13. The scroll compressor (1) according to any one of claims 1 to 12, wherein the oil siphon (47) further comprises a receiving chamber (54), the receiving chamber (54) being configured to collect oil flowing from the oil reservoir (34) through the calibrated oil outlet opening (36).

14. The scroll compressor (1) of claim 13, wherein the oil siphon device (47) further comprises an oil feed passage (58), the oil feed passage (58) fluidly connecting the receiving chamber (54) to the siphon chamber (55), the oil feed passage (58) being configured to allow oil collected in the receiving chamber (54) to flow into the siphon chamber (55).

15. A scroll compressor (1) according to claim 13 or 14, wherein the oil siphon (47) further comprises a pressure balancing opening (50), the pressure balancing opening (50) being present in the receiving chamber (54), the pressure balancing opening (50) being configured to ensure a pressure balance between the receiving chamber (54) and the low pressure volume (V) of the scroll compressor (1).

16. Scroll compressor (1) according to any of claims 1 to 15, wherein the support means (5) further comprises a through hole (68), said through hole (68) being present in the internal chamber (35) of the support means (5) and fluidly connecting the internal chamber (35) to an external space (69) defined by the support means (5) and the hermetic shell (2), said through hole (68) being configured to ensure a pressure balance between the internal chamber and the low pressure volume (V) of the scroll compressor (1).