DE102020200775A1 - Gas cyclone oil separator and air conditioning device for a motor vehicle - Google Patents

Abstract

The invention relates to a gas cyclone oil separator (10), comprising a jacket tube (16) provided at both ends with an outlet opening (19, 20), into which a gas-oil mixture under pressure via at least one inclined inlet channel (22) can be introduced in such a way that an external vortex flowing down from the inlet channel (22) occurs, which reverses in a lower region of the casing tube (16) to an internal vortex rising within the external vortex, whereby centrifugal forces on the wall of the casing tube (16) separated oil (24) escapes through the lower outlet opening (20) and gas cleaned of oil (24) escapes through the upper outlet opening (18). The invention is characterized in that the casing tube (16) has three cylindrical axial sections (161, 162, 163), namely a central inlet section (161), a reversal section (162) adjoining the inlet section (161) at the bottom, and a reversal section (162) at the top at the inlet section (161) adjoining outlet section (163), the inlet channel (22) opening tangentially into the inlet section (161) with a downward inclination.

Description

The invention relates to a gas cyclone oil separator, comprising a jacket tube provided with an outlet opening at each of its two ends, into which a gas-oil mixture can be introduced under pressure via at least one inclined inlet channel in such a way that an external vortex flowing down from the inlet channel is displaced which reverses in a lower region of the casing tube to an internal vortex rising within the external vortex, with oil separated by centrifugal forces on the wall of the casing tube escaping through the lower outlet opening and gas cleaned of oil through the upper outlet opening.

The invention further relates to an air conditioning device for a motor vehicle, comprising a compressor for gaseous refrigerant, with such a gas cyclone oil separator being connected downstream of the compressor.

Generic gas cyclone oil separators and air conditioning devices for motor vehicles are known from US Pat DE 102 44 588 A1 .

Air conditioning devices for motor vehicles regularly comprise a refrigerant circuit which, among other things, has a compressor for compressing gaseous refrigerant. To lubricate and cool the compressor and to seal gaps, oil is often added to the refrigerant in front of or in the compressor, so that the medium actually compressed by the compressor is a gas / oil suspension. The other components, typically contained in a refrigerant circuit, such as a condenser, an expansion valve, an evaporator, etc., should, however, only come into contact with largely pure refrigerant in order to avoid contamination. It is therefore known to connect a cleaning device downstream of the compressor in which the compressed refrigerant gas is cleaned of the added oil. Such cleaning devices are often designed in the form of a gas cyclone oil separator. The basic functional principle of the gas cyclone oil separator is to cause the gas / oil suspension to swirl within a so-called casing pipe, whereby the oil contained is thrown against the casing pipe wall due to the acting centrifugal forces, separates there and is driven by gravity on the wall of the more or less vertically aligned casing pipe runs down to a lower outlet opening. From there it can be returned and fed back to the refrigerant before or in the compressor. Typical gas cyclone oil separators are designed in such a way that the suspension vortex that forms in the casing pipe descends as an outer vortex with a larger diameter, where the gas freed from the oil forms an upwardly ascending inner vortex of smaller diameter, which inside the outer vortex leads to an upper outlet opening of the jacket pipe flows. The cleaned gas exiting there can then be fed to the downstream components of the refrigerant circuit.

Gas cyclone oil separators with a so-called immersion pipe are known, which extends from the upper outlet opening into the interior of the casing pipe so that the outer vortex is established in the annular gap between the immersion pipe and casing pipe, whereas the ascending inner vortex is essentially shorter than the jacket tube designed immersion tube flows.

The generic publication mentioned above discloses a gas cyclone oil separator without an immersion tube, which can be advantageous in principle with regard to installation space and material savings. The jacket pipe here has a conical shape that tapers from top to bottom. The upper end of the conical jacket tube is closed with a cover plate which has the upper outlet opening in its center, which is connected to an outlet tube leading to the downstream components of the refrigerant circuit. Furthermore, a plurality of inlet openings arranged in a ring around the outlet opening are provided in the cover plate, each of which is connected to an inlet channel for the compressed gas / oil suspension, the axial direction of each inlet channel (including the associated inlet opening) not being parallel to the axial direction of the casing tube, but has a tangentially tapered orientation. By introducing the compressed suspension at an angle, the downwardly descending external vortex is formed even without the presence of a dip tube. The conical design of the jacket tube narrows the outer vortex in its course and forces the direction reversal, i.e. the formation of the inner vortex, which then leaves the jacket tube via the central outlet opening in the cover plate. Such a design has several disadvantages. On the one hand, the radial installation space is comparatively large due to the conical shape of the casing tube. The cleaning effect is then unsatisfactory since there is a risk of mixing of internal and external vortices, particularly in the narrow tip area, which can lead to re-contamination of the gas that has already been cleaned. And finally, the edge regions of the ascending inner vortex in the vicinity of the cover plate can develop a dynamic pressure acting on the inlet openings, which slows down the introduced suspension flows in a disadvantageous manner.

It is the object of the present invention to provide a more efficient and space-saving gas cyclone oil drain.

This object is achieved in connection with the features of the preamble of claim 1 in that the jacket tube has three cylindrical axial sections, namely a central inlet section, a reversal section adjoining the inlet section at the bottom and an outlet section adjoining the inlet section at the top, the inlet channel - Relative to the axial direction of the casing tube - opens tangentially with a downward inclination into the inlet section.

Preferred embodiments of the invention are the subject of the dependent claims.

According to the invention, the jacket tube is essentially cylindrical. A cylindrical jacket tube is particularly easy to manufacture, namely through one or more bores. However, the cylindrical shape is also functionally advantageous. As a result, stable eddies can form that do not experience any spatial compression due to a conical shape and therefore do not run the risk of mixing with one another. The cleaning efficiency of the oil separator according to the invention increases as a result. However, the cylindrical design of the jacket tube is associated with increased difficulty in generating a stable external vortex without a central immersion tube. The invention solves this problem, on the one hand, by dividing the jacket tube into three parts: an inlet section, a reversing section and an outlet section. H. that section into which the inlet channel opens is arranged centrally between the lower reversal section and the upper outlet section. The inlet channel opens tangentially into the inlet section. Here the introduced suspension comes into direct contact with the curved jacket pipe wall and is forced into the circular movement required to form the vortex.

In order to ensure that the external vortex builds up reliably downwards in the direction of the reversal section, the invention further provides that the inlet channel has a slight, downwardly inclined position. In contrast to a purely tangential inlet channel, ie with an inlet channel opening perpendicular to the axial direction of the casing pipe, in which the direction of the vortex formation is dependent on minor disturbances and therefore cannot be reliably predicted, with a slightly oblique tangential introduction, as provided according to the invention, the Direction of vortex formation clearly specified. The upper part of the jacket pipe, d. H. the outlet section is initially not affected by the external vortex. As described above, this continues downward to the reversal section, at the end of which it necessarily reverses, namely in the form of the upwardly directed internal vortex. The lower outlet opening provided at the lower end of the reversing section, through which the oil separated on the casing pipe wall drains, is preferably narrowed compared to the casing pipe diameter there. In this way, the direction of the vortex is safely reversed and the outer vortex is prevented from flowing through the lower outlet opening. The upper outlet opening through which the upwardly directed internal vortex escapes, however, preferably does not have such a constriction. On the contrary, it is considered beneficial if, in order to avoid dynamic pressure, the upper outlet opening has the same diameter as the outlet section of the jacket tube, i.e. H. occupies its entire cross-section.

To achieve an advantageous, high inflow velocity, it is advantageous to keep the cross section of the inlet channel as small as possible. On the other hand, a certain volume throughput must be guaranteed in order to be able to clean and pass on the entire suspension supplied by the compressor. In an advantageous development of the invention, it is therefore provided that a plurality of inlet channels spaced axially from one another open tangentially into the inlet channel with the same inclination. Particularly preferably, the mouths of the inlet channels lie equidistantly on the same axially aligned straight line. In other words, in relation to the axial direction of the casing tube, they are arranged at equal distances from one another one above the other within the inlet section, the suspension flows running parallel through all the mouth openings of the inlet channels. The individual inlet streams combine to form a "band" which screws itself down helically.

steht.For optimal vortex guidance, the suspension inlet and the jacket pipe must be dimensioned to match. Such an optimized dimensioning is achieved in that the inclination angle α of the inlet channels is in relation to their number n, their distance d and to the inner radius r of the inlet section $$\alpha =\text{arctan}\left(\raisebox{1ex}{$nd$}\!\left/ \!\raisebox{-1ex}{$2\pi r$}\right.\right)$$

stands.

As a result, the gradient of the helix of the aforementioned flow "band" is designed in such a way that the upper edge of this "band" moves after exactly one revolution (360 °), calculated from one any reference angle, exactly at its lower edge at said reference angle. Different screw threads of the "tape" do not overlap; Nor are there any gaps between the individual screw threads. In other words, the entire inner wall of the casing pipe is completely and evenly covered, which leads to optimal oil separation and therefore maximum cleaning efficiency.

In principle, it is conceivable that all three sections of the jacket tube have the same diameter. It has surprisingly been found, however, that it is more favorable if the inlet section has a smaller diameter than the reversing section and the outlet section. In this way, particularly rapid vortex generation is guaranteed in the inlet section. The reversal section, however, with its enlarged diameter acts as a calming zone, which benefits the stabilization of the eddy and which facilitates the reversal of direction insofar as the cross-section required for the formation of the inner eddy increases. For the ascending internal vortex, which has to pass the narrower inlet section again, the narrowing there acts as a nozzle that accelerates the cleaned gas in the direction of the outlet section. In addition, the narrowing prevents the external vortex from turning upwards.

For reasons of installation space and production, it can be advantageous if the axial direction of the casing tube is inclined relative to the vertical. The inclination must of course not be so great that the separated oil can no longer drain to the lower outlet opening, driven by gravity. In terms of production engineering, an inclined position of the jacket tube is particularly advantageous if it is directed and designed in such a way that the inlet channel or channels runs essentially horizontally in its mouth area.

The preferred area of application of a gas cyclone oil separator according to the invention is the cleaning of gas / oil suspension from the compressor of an air conditioning device for a motor vehicle. A corresponding air conditioning device is therefore an independent component of the present invention.

Further details and advantages of the invention emerge from the following specific description and the drawings.

• 1 eine schematisierte Längsschnittdarstellung einer bevorzugten Ausführungsform des erfindungsgemäßen Gaszyklon-Ölabscheider sowie
• 2 eine Querschnittsdarstellung durch den Ölabscheider von 1 entlang der Schnittlinie II-II.

Show it:

• 1 a schematic longitudinal sectional view of a preferred embodiment of the gas cyclone oil separator according to the invention and
• 2 a cross-sectional view through the oil separator of 1 along the section line II-II.

Identical reference symbols in the figures indicate identical or analogous elements.

1 shows a schematic representation of a longitudinal section through a preferred embodiment of a gas cyclone oil separator according to the invention 10 . The oil separator 10 is connected downstream of a compressor of the refrigerant circuit of a motor vehicle air conditioning device. The compressor is in 1 not shown in detail. Just a section of his high pressure room 12th is together with an arrow 14th to symbolize the refrigerant flow to the oil separator 10 shown.

The oil separator 10 essentially comprises a jacket tube 16 which is divided into three substantially cylindrical sections 161 , 162 163 is divisible. This is the central inlet section 161 located at the bottom of the inlet section 161 subsequent reversal section 162 and the one at the top of the inlet section 161 subsequent outlet section 163 . The axial direction of the casing pipe 16 is arranged slightly inclined in the embodiment shown for reasons of space. However, exactly vertical or other beveled orientations are also conceivable. The relative positioning of "below" and "above" in relation to the direction of gravity in the final assembly state should, however, be retained.

The jacket tube has at its upper end 16 , in particular its outlet section 163 , an upper exhaust port 18th on, which is used for the outlet of the purified gas. The jacket tube has at its lower end 16 , especially its reversal section 162 , a lower exhaust port 20th on, which is used to drain the separated oil.

From the high pressure room 12th of the compressor, a compressed gas / oil suspension passes through inlet channels 22nd into the inlet section 161 . As in 2 recognizable, the inlet channels open 22nd tangential to the inlet area 161 . How out 1 can be seen, this is done with a slight, downward inclination (relative to the axial direction of the jacket pipe 16 ). This creates a downwardly directed suspension vortex along the cylindrical surface of the inlet area 161 . This external vortex settles in the deflection section 162 where, due to the centrifugal forces prevailing in the external vortex, the oil contained in the suspension as droplets 24 is deposited on the jacket pipe wall. Driven by gravity, the oil runs down the casing pipe wall and collects in front of the lower outlet opening 20th through which it can be diverted and returned to the compressor for lubrication.

The cleaned gas experiences in the lower area of the reversal section 162 reverses direction and forms an inner vortex that moves radially upward within the outer vortex. This crosses the inlet section 161 and the outlet section 163 . at its upper end the purified gas through the outlet opening 18th from the oil separator 10 released and fed to the further refrigerant circuit via pipes or hoses, not shown.

At the in 1 The embodiment shown is the diameter of the inlet section 161 compared to the diameter of the reversal section 162 and the outlet section 163 narrowed. This leads to vortex formation with a particularly high initial speed. The reversal section 162 then acts as a calming zone for the outer vortex, which also favors the reversal of direction and the formation of the inner vortex due to the associated creation of a larger interior space. On the other hand, it is used when passing through the inlet area again 161 its cross-sectional constriction as a nozzle accelerating the internal vortex upwards, which also stabilizes the complicated vortex conditions in the jacket pipe 16 and especially in its reversal section 162 serves. The ascending inner vortex is experienced in the outlet section with a wider cross-section 163 a calming effect, which among other things has a positive acoustic effect on the further refrigerant flow.

Of course, the embodiments discussed in the specific description and shown in the figures represent only illustrative embodiments of the present invention. In the light of the disclosure here, a person skilled in the art is provided with a broad spectrum of possible variations.

List of reference symbols

10

Gas cyclone oil separator

12th

Compressor high pressure chamber

14th

arrow

16

Jacket pipe

161

Inlet section of 16

162

Reversal section of 16

163

Outlet section of 16

18th

upper outlet opening

20th

lower outlet opening

22nd

Inlet port

24

Oil droplets

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 10244588 A1 [0003]

Claims (8)

Gas cyclone oil separator (10), comprising a jacket tube (16) which is provided at both ends with an outlet opening (19, 20) and into which a gas-oil mixture can be introduced under pressure via at least one inclined inlet channel (22) in such a way that an outer vortex flowing down from the inlet channel (22) is set up, which reverses in a lower region of the casing tube (16) to an inner vortex rising within the outer vortex, with oil (24) separated by centrifugal forces on the wall of the casing tube (16) through the lower outlet opening (20) and gas cleaned of oil (24) escapes through the upper outlet opening (18), characterized in that the jacket tube (16) has three cylindrical axial sections (161, 162, 163), namely a central inlet section (161 ), a reversal section (162) adjoining the inlet section (161) at the bottom and an outlet section (163) adjoining the inlet section (161) at the top, wherein the inlet channel (22) opens tangentially into the inlet section (161) with a downward inclination. Gas cyclone oil separator (10) Claim 1 , characterized in that a plurality of axially spaced apart inlet channels (22) open tangentially with the same inclination in the inlet section (161). Gas cyclone oil separator (10) Claim 2 , characterized in that the mouths of the inlet channels (22) lie equidistantly on the same axially aligned straight line. Gas cyclone oil separator (10) Claim 3 , characterized in that the inclination angle α of the inlet channels (22) in relation to their number n, their distance d and to the inner radius r of the inlet section (161) $$\alpha =\text{arctan}\left(\raisebox{1ex}{$nd$}\!\left/ \!\raisebox{-1ex}{$2\pi r$}\right.\right)$$

stands. Gas cyclone oil separator (10) according to one of the preceding claims, characterized in that the inlet section (161) has a smaller diameter than the reversal section (162) and the outlet section (163). Gas cyclone oil separator (10) according to one of the preceding claims, characterized in that the axial direction of the casing tube (16) is inclined relative to the vertical. Gas cyclone oil separator (10) Claim 6 , characterized in that the at least one inlet channel (22) runs essentially horizontally in its mouth area. Air conditioning device for a motor vehicle, comprising a compressor for gaseous refrigerant, the compressor being followed by a gas cyclone oil separator (10), characterized in that the gas cyclone oil separator (10) is a gas cyclone oil separator (10) according to one of the preceding claims.

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