FR3116868A1 - Scroll compressor with discharge port baffle - Google Patents

Abstract

The scroll compressor (1) is provided with a compressor casing (2) having a discharge outlet (4); a fixed volute (7) comprising a fixed base plate (11) and a discharge passage (16) formed in the fixed base plate (11) and provided with a discharge orifice (17) opening into a pressure volume discharge (18) defined by the compressor casing (2) and the fixed volute (7); and a deflector (29) arranged in the discharge pressure volume (18), covering the discharge orifice (17) and delimiting a discharge opening (31) located opposite the discharge outlet (4), the deflector (29) being configured to force a flow of compressed refrigerant gas exiting the discharge port (17) from an axial direction to a radial direction and being configured to direct said flow of compressed refrigerant gas towards the discharge outlet (4). Figure 2

Description

Scroll compressor with discharge port baffle

Field of invention

The present invention relates to a scroll compressor having a baffle arranged in a discharge pressure volume bounded by a fixed volute and a compressor shell.

Background of the invention

Document JP 07189966 A shows a scroll compressor with a deflector device arranged in a discharge pressure volume and configured to change the direction of a flow of compressed refrigerant gas emerging from the compression chambers from a direction parallel to the pressure volume. longitudinal axis of the scroll compressor to a direction orthogonal to the longitudinal axis of the scroll compressor. By guiding the flow of compressed refrigerant gas to the side walls of the discharge pressure volume, direct impingement of the compressed refrigerant gas on the upper end wall surface of the compressor shell is avoided. Therefore, pulse noise is reduced.

When a discharge connection is formed in the upper end wall of the compressor shell, the compressed refrigerant gas is subjected to additional changes in its flow direction before leaving the discharge pressure volume. This leads to a significant pressure drop in the compressed refrigerant gas.

US 2019/0195224 A1 discloses a scroll compressor having a silencer attached to the fixed scroll base plate and covering a discharge port formed in the central part of the fixed scroll. Here too, a direct flow of compressed refrigerant gas to the upper end wall of the compressor shell is avoided. However, this solution again leads to an increased pressure drop in the compressed refrigerant gas, because several changes of the compressed refrigerant gas flow direction occur, before the compressed refrigerant gas leaves the muffler chamber through a hole. discharge outlet and flows to the discharge outlet of the compressor shell.

An object of the present invention is to provide an improved scroll compressor which can overcome the disadvantages encountered in conventional scroll compressors.

Another object of the present invention is to provide a scroll compressor with improved efficiency by reducing pressure losses in the discharge pressure volume.

Another object of the present invention is also to reduce the acoustic noise emitted by the compressor envelope.

According to the invention, such a scroll compressor comprises:

- a compressor envelope having a discharge outlet,

- an orbiting scroll arranged inside the compressor casing and comprising an orbiting base plate and an orbiting spiral winding extending from the orbiting base plate,

- a stationary scroll arranged within the compressor casing and comprising a stationary base plate and a stationary scroll wrap extending from the stationary base plate, the stationary and orbiting scroll wraps defining, with the fixed and orbiting baseplates, compression chambers, the fixed volute further comprising a discharge passage which is formed in the fixed baseplate and which has a discharge port opening into a discharge pressure volume defined at least partially by the compressor shell and the stationary scroll, and

- a deflector arranged in the discharge pressure volume, the deflector covering the discharge orifice and at least partially delimiting a discharge opening located opposite the discharge outlet of the compressor casing, the deflector being configured to force a flow of compressed refrigerant gas emerging from the discharge orifice to be passed, and advantageously to be passed easily, from an axial direction to a radial direction and being configured to direct, and in particular to guide, said flow of compressed refrigerant gas towards the discharge outlet.

Since the baffle extends over the discharge port and is configured to direct the flow of compressed refrigerant gas to the discharge outlet, a direct impact of the flow of compressed refrigerant gas on an upper end wall of the compressor is bypassed and the compressed refrigerant gas is not subjected to several changes in its flow direction before leaving the discharge pressure volume, thereby substantially reducing pressure losses in the discharge pressure volume while suppressing pulsations and resonance waves between the compressor shell and the discharge port.

Consequently, the acoustic behavior and the efficiency of the scroll compressor according to the present invention are significantly improved compared to the acoustic behavior and the efficiency of the compressors of the prior art. Particularly, large improvements (up to – 4 dB) have been observed, especially for frequencies at 2.5 kHz.

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

According to one embodiment of the invention, the discharge passage extends substantially parallel to the longitudinal axis of the scroll compressor.

According to one embodiment of the invention, the discharge passage is configured to fluidically connect the compression chambers to the discharge pressure volume.

According to one embodiment of the invention, the discharge port is provided at a central part of the fixed base plate of the fixed volute.

According to one embodiment of the invention, the discharge outlet is provided on a top cap of the compressor casing. Advantageously, the discharge outlet is provided on a side wall of said top cap.

According to one embodiment of the invention, the deflector has an elbow shape.

According to one embodiment of the invention, the deflector is fixed to the fixed base plate of the fixed volute.

According to one embodiment of the invention, the deflector is attached to a baseplate face of the fixed baseplate opposite the compression chambers.

According to one embodiment of the invention, the deflector comprises a first end fixed in leaktight manner to the fixed base plate of the fixed volute, and a second end at least partially delimiting the discharge opening.

According to one embodiment of the invention, the first end of the deflector is fixed in a sealed manner to the fixed base plate of the fixed volute close to the discharge orifice.

According to one embodiment of the invention, the discharge opening opens into the discharge pressure volume at a predetermined separation distance from the discharge outlet to allow communication between the flow of compressed refrigerant gas and the pressure volume of repression.

According to one embodiment of the invention, the scroll compressor further includes a discharge check valve assembly attached to the discharge outlet of the compressor shroud and configured to prevent backflow of refrigerant from a tube of a refrigeration system in the discharge pressure volume, when the scroll compressor stops.

According to one embodiment of the invention, the discharge check valve assembly includes a tubular valve housing having an inlet opening leading into the discharge pressure volume and an outlet opening leading outside of the compressor shell and configured to be fluidly connected to the outer tube of a refrigeration system.

According to one embodiment of the invention, the discharge opening is located opposite the inlet opening of the tubular valve housing and is located at a predetermined spacing distance from the inlet opening of the housing of tubular valve.

According to one embodiment of the invention, a ratio between the cross section of the inlet opening and the cross section of the discharge opening is between 0.8 and 1.2, and for example between 0. 9 and 1.1. In other words, the inlet opening of the tubular valve housing and the outlet opening are of similar size.

According to one embodiment of the invention, the discharge opening and the inlet opening are configured such that a major portion of the compressed refrigerant gas leaving the fixed scroll discharge port is supplied directly into the inlet opening of the tubular damper housing. Such a configuration of the discharge check valve and baffle assembly helps reduce pressure losses in the compressed refrigerant gas stream.

According to one embodiment of the invention, the discharge passage comprises a wall portion having a curved convex surface portion directed towards the discharge outlet, and advantageously towards the discharge check valve assembly and in particular towards the inlet opening of the tubular valve housing.

According to one embodiment of the invention, the baffle and the curved convex surface portion of the discharge passage define a smooth surface structure. Such a configuration of the deflector and of the discharge passage makes it possible to further reduce pressure losses. This is particularly important when using low density refrigerants, e.g. low GWP refrigerants, as an increased volume flow is required to maintain a given cooling capacity.

According to one embodiment of the invention, the deflector comprises an upper wall part having an internal deflecting surface part which is concave and curved, the internal deflecting surface part being directed towards the discharge outlet. Such a configuration of the discharge passage makes it possible to further reduce the pressure losses in the flow of compressed refrigerant gas.

The baffle can be fabricated as a sintered, pressed, punched, machined, or cast metal component. Preferably, the deflector is made as a molded or 3D printed plastic component.

Advantageously, the deflector is fixed to the fixed volute using screws or bolts. However, other suitable processes, for example welding, brazing, stamping or gluing can be applied to attach the deflector to the fixed volute.

These advantages as well as others will appear on reading the following description taking into account the attached drawings which represent, by way of non-limiting example, embodiments of a scroll compressor according to the invention.

The following detailed description of several embodiments of the invention is best understood when read in conjunction with the accompanying drawings, it being, however, understood that the invention is not limited to the specific embodiments disclosed.

There is a longitudinal sectional view of a scroll compressor according to the invention.

There is a partial longitudinal sectional view of the scroll compressor of the showing a discharge check valve assembly in a closed position.

There is a partial longitudinal sectional view of the scroll compressor of the showing the discharge check valve assembly in an open position, and wherein a discharge passage has a wall portion having a chamfer.

There is a partial longitudinal sectional view of the scroll compressor of the showing the discharge check valve assembly in an open position, and wherein the discharge passage has a wall portion having a curved convex surface portion.

There is a partial top view of the scroll compressor of the .

There is a perspective view of a scroll compressor baffle of the .

Detailed description of the invention

There describes a scroll compressor 1 according to the invention occupying a vertical position.

The scroll compressor 1 comprises a compressor envelope 2 provided with a suction inlet 3 configured to supply the scroll compressor 1 with the refrigerant to be compressed, and a discharge outlet 4 configured to discharge the compressed refrigerant. The discharge outlet 4 is advantageously provided on a side wall of an upper cap of the compressor casing 2.

The scroll compressor 1 further comprises a support arrangement 5 fixed to the compressor casing 2, and a compression unit 6 arranged inside the compressor casing 2 and supported by the support arrangement 5. The compressor unit 6 is configured to compress the refrigerant supplied by the suction inlet 3. The compressor unit 6 comprises a fixed volute 7, which is fixed with respect to the compressor casing 2, and a orbiting volute 8 supported by and in sliding contact with a thrust bearing surface 9 provided on support arrangement 5.

The fixed volute 7 comprises a fixed base plate 11 having a lower face facing the orbiting volute 8, and an upper face opposite the lower face of the fixed base plate 11. The fixed volute 7 also comprises a fixed spiral winding 12 protruding from the underside of the fixed base plate 11 towards the orbiting volute 8.

The orbiting volute 8 comprises an orbiting base plate 13 having an upper face facing the fixed volute 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 also has an orbiting spiral wrap 14 projecting from the top face of the orbiting base plate 13 towards the fixed scroll 7. The orbiting spiral wrap 14 of the orbiting scroll 8 meshes with the orbiting scroll 8. fixed spiral 12 of the fixed volute 7 to form a plurality of compression chambers 15 between them. Each of the compression chambers 15 has a variable volume which decreases from outside to inside, when the orbiting volute 8 is driven so as to orbit with respect to the fixed volute 7.

The fixed volute 7 further comprises a discharge passage 16 which is formed in a central part of the fixed base plate 11 and which is fluidly connected to the compression chambers 15. The discharge passage 16 extends parallel to the longitudinal axis of the scroll compressor 1, and is provided with a discharge port 17 opening into a discharge pressure volume 18 defined by the compressor shell 2 and the fixed volute 7. Consequently, the discharge passage 16 is configured to fluidly connect the compression chambers 15 to the discharge pressure volume 18.

Further, the scroll compressor 1 has a drive shaft 19 which extends vertically and which is configured to drive the orbiting scroll 8 in orbital motion, and an electric drive motor 21, which may for example be a variable speed electric drive motor, coupled to the drive shaft 19 and configured to drive the drive shaft 19 in rotation about an axis of rotation A.

The scroll compressor 1 further includes a discharge check valve assembly 22 attached to the discharge outlet 4 and fluidly connected to the discharge pressure volume 18. The discharge check valve assembly 22 is particularly configured to prevent backflow of refrigerant from a high pressure side of a refrigeration system into the discharge pressure volume 18 when the scroll compressor 1 shuts down.

The discharge check valve assembly 22 includes a tubular valve housing 23 inserted into the discharge outlet 4 of the compressor shell 2 and sealed to the discharge outlet 4. The tubular valve housing 23 has a first end part 23.1 arranged inside the discharge pressure volume 18 and provided with an inlet opening 24 opening into the discharge pressure volume 18, and a second end part 23.2 arranged at the exterior of the compressor casing 2 and provided with an outlet opening 25 opening outside the compressor casing 2 and configured to be fluidly connected to the refrigeration system. According to the embodiments shown in Figures 1 to 6, the second end part 23.2 of the tubular valve housing 23 acts as a fitting to connect the external tube of the refrigeration system.

The discharge check valve assembly 22 further includes a valve seat 26 located within the tubular valve housing 23 and formed at the inner surface of the tubular valve housing 23. The valve seat 26 is annular and extends around the inlet opening 24. Advantageously, the valve seat 26 is provided on the first end part 23.1.

The discharge check valve assembly 22 also includes a valve member 27 arranged in the tubular valve housing 23 and movable between a closed position (see ) in which the valve member 27 bears against the valve seat 26 and an open position (see ) in which the valve member 27 is remote from the valve seat 26.

The discharge check valve assembly 22 further includes a biasing member 28, such as a spring member, configured to bias the valve member 27 toward the closed position.

The scroll compressor 1 also includes a baffle 29 arranged in the discharge pressure volume 18 and covering the discharge port 17. The baffle 29 can be manufactured as a sintered, pressed, punched, machined or cast metal component. However, deflector 29 is preferably made as a molded or 3D printed plastic component.

The deflector 29 comprises a first end 29.1 fixed in leaktight manner to the upper face of the fixed base plate 11 of the fixed volute 7 and located close to the discharge orifice 17, and a second end 29.2 at least partially delimiting a discharge opening 31 located opposite the discharge outlet 4 of the compressor casing 2 and the inlet opening 24. According to the embodiments shown in the figures, the discharge opening 31 is delimited by the plate fixed base 11 of the fixed volute 7 and the second end 29.2 of the deflector 29. However, the discharge opening 31 can for example be entirely delimited by the second end 29.2 of the deflector 29.

Advantageously, the deflector 29 is fixed to the fixed volute 7 using screws or bolts. However, other suitable methods, for example welding, brazing, interference fitting or gluing can be applied to attach the deflector 29 to the fixed volute 7.

According to the embodiments shown in the figures, the deflector 29 has an elbow shape and comprises an upper wall part 32 having an internal deflecting surface part which is concave and curved and which is directed towards the discharge outlet 4.

The baffle 29 is configured to direct a flow of compressed refrigerant gas exiting the discharge port 17 towards the discharge outlet 4, and in particular towards the outlet opening 25 of the tubular valve housing 23. The baffle 29 is also configured to cause said flow of compressed refrigerant gas to easily change from an axial direction to a radial direction, with respect to the longitudinal axis of the scroll compressor.

According to the embodiments shown in the figures, the discharge opening 31 is located opposite the inlet opening 24 of the tubular valve housing 23 and opens into the discharge pressure volume 18 at a predetermined separation distance D1 from the discharge outlet 4 and is located at a predetermined spacing distance D2 from the inlet opening 24 of the tubular valve housing 23, to allow communication between the flow of compressed refrigerant gas and the pressure volume of outlet 18, and to facilitate mounting of the outlet check valve assembly 22 relative to the deflector 29. The predetermined spacing distance D2 is between 2 and 40 mm, and advantageously between 10 and 30 mm. However, the discharge opening 31 and the inlet opening 24 are configured so that a major part of the compressed refrigerant gas leaving the discharge port 17 of the fixed scroll 7 is supplied directly into the opening of inlet 24 of the tubular valve housing 23.

A ratio between the cross section of the inlet opening 24 and the cross section of the discharge opening 31 is between 0.8 and 1.2, and advantageously between 0.9 and 1.1, so that the inlet opening 24 of the tubular valve housing 23 and the discharge opening 31 are of similar size.

According to the embodiment shown in the , the discharge passage 16 includes a wall portion 33 having a curved convex surface portion directed toward the inlet opening 24 of the tubular valve housing 23. Advantageously, the inner surface of the baffle 29 and the curved convex surface portion of the discharge passage 16 defines a smooth surface structure. Such a configuration of the deflector 29 and of the discharge passage 16 makes it possible to further reduce the pressure losses. This is particularly important when using low density refrigerants, e.g. low GWP (global warming potential) refrigerants, as an increased volume flow is required to maintain a given cooling capacity.

However, according to alternative embodiments of the invention, the discharge passage 16 may include a wall portion 33 defined by a chamfer (see ) or a wall portion 33 which is cylindrical (see ).

The operation of the scroll compressor 1 will now be described.

When the scroll compressor 1 according to the invention is started, the orbiting volute 8 is driven by the drive shaft 19 following an orbital movement, this movement of the orbiting volute 8 causing an admission and a compression of refrigerant in the compression chambers 15. The compressed refrigerant gas exits to the discharge pressure volume 18 via the discharge passage 16 and the discharge port 17 formed in the central part of the fixed volute 7, is guided towards the opening 24 of the tubular valve housing 23 by the baffle 29, moves the valve member 27 into the open position against the biasing force exerted by the biasing member 28, and then flows through the valve housing tubular 23 and the outlet opening 25 of the tubular valve housing 23.

Due to the configuration of the baffle 29, the wall portion 33 of the discharge passage 16 and the inlet opening 24 of the tubular valve housing 23, the pressure losses in the compressed refrigerant gas are considerably reduced, which which significantly improves the efficiency and performance of the scroll compressor 1.

When the scroll compressor 1 according to the invention stops, the biasing element 28 biases the valve member 27 towards the closed position, which prevents the high pressure refrigerant from returning to the discharge pressure volume. 18.

Of course, the invention is not limited to the embodiments described above by way of non-limiting example, but on the contrary it encompasses all the corresponding embodiments.

Claims (12)

Scroll compressor (1) comprising:
- a compressor envelope (2) having a discharge outlet (4),
- an orbiting scroll (8) arranged inside the compressor casing (2) and comprising an orbiting base plate (13) and an orbiting spiral winding (14) extending from the base plate orbiting (13),
- a fixed scroll (7) arranged inside the compressor casing (2) and comprising a fixed base plate (11) and a fixed spiral winding (12) extending from the base plate stationary (11), the stationary and orbiting spiral windings (12, 14) defining, together with the stationary and orbiting base plates (11, 13), compression chambers (15), the stationary volute (7) further comprising a discharge passage (16) which is formed in the fixed base plate (11) and which has a discharge port (17) opening into a discharge pressure volume (18) at least partially defined by the compressor casing (2) and the fixed volute (7), and
- a deflector (29) arranged in the discharge pressure volume (18), the deflector (29) covering the discharge orifice (17) and at least partially delimiting a discharge opening (31) located opposite the outlet discharge port (4) of the compressor shell (2), the baffle (29) being configured to force a flow of compressed refrigerant gas exiting the discharge port (17) to pass from an axial direction to a direction radial and being configured to direct said flow of compressed refrigerant gas towards the discharge outlet (4). Scroll compressor (1) according to claim 1, wherein the deflector (29) has an elbow shape. Scroll compressor (1) according to claim 1 or 2, wherein the deflector (29) is fixed to the fixed base plate (11) of the fixed scroll (7). Scroll compressor (1) according to any one of Claims 1 to 3, in which the deflector (29) has a first end (29.1) sealingly fixed to the fixed base plate (11) of the fixed scroll (7 ), and a second end (29.2) at least partially delimiting the discharge opening (31). Scroll compressor (1) according to any of claims 1 to 4, wherein the discharge opening (31) opens into the discharge pressure volume (18) at a predetermined separation distance (D1) from the outlet outlet (4) to allow communication between the flow of compressed refrigerant gas and the outlet pressure volume (18). A scroll compressor (1) as claimed in any one of claims 1 to 5, further comprising a discharge check valve assembly (22) attached to the discharge outlet (4) of the compressor casing (2) and configured to prevent backflow of refrigerant from an outer tube of a refrigeration system into the discharge pressure volume (18), when the scroll compressor (1) stops. A scroll compressor (1) as claimed in claim 6, wherein the discharge check valve assembly (22) comprises a tubular valve housing (23) having an inlet opening (24) opening into the pressure volume outlet (18) and an outlet opening (25) opening outside the compressor casing (2) and configured to be fluidically connected to the outer tube of a refrigeration system. Scroll compressor (1) according to Claim 7, in which the discharge opening (31) is located opposite the inlet opening (24) of the tubular valve housing (23) and is located at a distance of predetermined spacing (D2) of the inlet opening (24) of the tubular valve housing (23). Scroll compressor (1) according to Claim 7 or 8, in which a ratio between the cross-section of the inlet opening (24) and the cross-section of the discharge opening (31) is between 0.8 and 1.2, and for example between 0.9 and 1.1. Scroll compressor (1) according to any one of claims 7 to 9, in which the discharge opening (31) and the inlet opening (24) are configured so that the major part of the compressed refrigerant gas leaving the discharge port (17) of the fixed volute (7) is provided directly into the inlet opening (24) of the tubular valve housing (23). A scroll compressor (1) according to any one of claims 1 to 10, wherein the discharge passage (16) includes a wall portion having a curved convex surface portion directed towards the discharge outlet (4). A scroll compressor (1) according to claim 11, wherein the baffle (29) and the curved convex surface portion of the discharge passage (16) define a smooth surface structure.