Spiral compressor with oil recirculation unit

Abstract

A scroll compressor with oil return unit, having a fixed spiral and an orbiting spiral, which compresses gas from a suction-pressure chamber into a high-pressure chamber. A counter-pressure chamber is connected to the orbiting spiral and the orbiting spiral presses onto the fixed spiral. The oil return unit has a counter-pressure spiral nozzle having a high-pressure channel connected to an end face for oil supply. A suction-pressure spiral nozzle with a suction-pressure channel connected to the end face discharges oil into the suction-pressure chamber. A counter-pressure channel is arranged between the counter-pressure spiral nozzle and the suction-pressure spiral nozzle for discharging oil into the counter-pressure chamber.

Claims

1. A scroll compressor with oil return unit, the scroll compressor comprising: a fixed spiral and an orbiting spiral which compress gas from a suction-pressure chamber into a high-pressure chamber; a counter-pressure chamber is connected to the orbiting spiral and the orbiting spiral presses onto the fixed spiral, wherein the oil return unit has a counter-pressure spiral nozzle having a high-pressure channel connected to an end face thereto for oil supply and a suction-pressure spiral nozzle with a suction-pressure channel connected to the end face thereto for discharging oil into the suction-pressure chamber, wherein a counter-pressure channel is arranged between the counter-pressure spiral nozzle and the suction-pressure spiral nozzle for discharging oil into the counter-pressure chamber, wherein the counter-pressure spiral nozzle is formed from a cylindrical cavity in the fixed spiral and a spiral nozzle insert and the suction-pressure spiral nozzle is formed from a cylindrical cavity in a middle housing and the spiral nozzle insert, and wherein the cylindrical cavity in the fixed spiral has an expansion region in the fixed spiral, in which the spiral nozzle insert does not make contact with the cylindrical cavity in the fixed spiral wherein the expansion region is arranged downstream of a counter-pressure throttle region of the counter-pressure spiral nozzle, and wherein oil is released by throttling while passing through the counter-pressure throttle region, and then delivered to the suction-pressure spiral nozzle through the expansion region where throttling is not performed.

2. The scroll compressor according to claim 1, wherein the cylindrical cavity in the middle housing has an expansion region, in which the spiral nozzle insert does not make contact with the cylindrical cavity in the middle housing.

3. The scroll compressor according to claim 2, wherein the cylindrical cavities have a larger diameter in the expansion region such that no throttling occurs in the expansion region.

4. The scroll compressor according to claim 2, wherein the cylindrical cavities have a uniform diameter over an entire length and the spiral nozzle insert has a reduced diameter in the expansion region such that no throttling occurs in the expansion region.

5. The scroll compressor according to claim 1, wherein the high-pressure channel is tilted at an angle α sloping from the high-pressure chamber to the counter-pressure spiral nozzle.

6. The scroll compressor according to claim 1, wherein the high-pressure channel is formed as a supply borehole, wherein the supply borehole is formed from a central borehole coaxially with respect to the cylindrical cavity in the fixed spiral and a stepped borehole offset axially thereto and the stepped borehole and the central borehole are arranged one below the other from the high-pressure chamber to the counter-pressure spiral nozzle and include a notch.

7. The scroll compressor according to claim 1, wherein a wear plate with a flow borehole is arranged between the counter-pressure spiral nozzle and the suction-pressure spiral nozzle.

8. The scroll compressor according to claim 1, wherein a first inlet region is arranged upstream of a counter-pressure throttle region of the counter-pressure spiral nozzle.

9. The scroll compressor according to claim 8, wherein a second inlet region with a branch to the counter-pressure channel is arranged upstream of a suction-pressure throttle region of the suction-pressure spiral nozzle.

10. The scroll compressor according to claim 9, wherein a collection area is arranged downstream of the counter-pressure throttle region and downstream of the suction-pressure throttle region.

Description

DRAWINGS

(1) Further details, features, and advantages of embodiments of the invention result from the following description of exemplary embodiments with reference to the corresponding drawings. The following is shown:

(2) FIG. 1: Detailed view of a scroll compressor with an oil return unit having a counter-pressure spiral nozzle;

(3) FIG. 2: The scroll compressor according to FIG. 1 with suction-pressure spiral nozzle;

(4) FIG. 3: Detailed view of the oil return unit with inclined high-pressure channel; and

(5) FIGS. 4, 5: Detailed views of the oil return unit with offset supply borehole as a high-pressure channel.

DETAILED DESCRIPTION

(6) The cutout of the scroll compressor 1 with an oil return unit 2 is shown in detail in FIG. 1.

(7) The scroll compressor 1 has a fixed spiral 11 and an orbiting spiral 12 moving in said fixed spiral. Between the spirals, there are resulting chambers that change during the movement, which have a low or a high pressure depending on the position of the spirals 11, 12 with respect to one another. The refrigerant gas-oil mixture reaches the high-pressure chamber 8 under high pressure, wherein the oil is separated out after the compression process in the high-pressure chamber 8 and supplied from there to the suction-pressure chamber 9 by means of the oil return unit 2.

(8) The refrigerant gas is suctioned with the oil from the suction-pressure chamber 9, then compressed between the spirals 11, 12, and conveyed to the high-pressure chamber 8; the circuit is closed.

(9) The oil return unit 2 is used to convey the oil separated after the compression process from the high-pressure chamber 8 back into the suction-pressure chamber 9 and, in doing so, additionally to provide a partial quantity of the oil at a medium pressure, which is also characterized as a counter-pressure in a counter-pressure chamber 10. The counter-pressure is necessary in order to press the orbiting spiral 12 against the fixed spiral 11 and to establish equilibrium of forces between the forces in the high-pressure chamber 8 on one side of the orbiting spiral 12 and the forces in the counter-pressure chamber 10 on the other side of the orbiting spiral 12.

(10) The oil return unit 2 consists of a counter-pressure spiral nozzle 3 and a suction-pressure spiral nozzle 4. The counter-pressure spiral nozzle 3 is formed by means of a spiral nozzle insert 20 in a cylindrical cavity 21 within the fixed spiral 11. The throttle effect of the counter-pressure spiral nozzle 3 is finally achieved by means of the spiral nozzle insert 20, with which a corresponding spiral or ring groove forms a ring groove of defined size and length along the inner surface of the cylindrical cavity 21 and within which the refrigerant oil flows from the high-pressure chamber 8, via the high-pressure channel 5, into the area of the counter-pressure spiral nozzle 3 and is throttled in doing so.

(11) At the start of the counter-pressure spiral nozzle 3, an inlet region 13 is provided, which enables uniform distribution of the refrigerant oil along the wall of the cylindrical cavity 21, before the oil enters the ring groove or spiral groove. The area of the actual throttling of the counter-pressure spiral nozzle 3 is characterized as the counter-pressure throttle region 14. After passing through the counter-pressure throttle region 14, the oil is brought to the counter-pressure level and reaches the collection area 16, by means of the expansion region 15 of the counter-pressure spiral nozzle 3 in the fixed spiral 11, where the oil is collected and transferred into the next area of the oil return unit 2. The throttle effect on the oil takes place almost exclusively in the counter-pressure throttle region 14, while the subsequent expansion region 15 and the collection area 16 have essentially no throttle effect on the oil. In the middle housing 18, a cylindrical cavity 22 is arranged with the suction-pressure spiral nozzle 4, which is connected to the suction-pressure chamber 9 by means of the suction-pressure channel 6. Furthermore, the counter-pressure chamber 10 is connected to the cylindrical cavity 22 by means of the counter-pressure channel 7.

(12) In contrast to FIG. 1, the suction-pressure spiral nozzle 4 is broken down into greater detail in FIG. 2. The refrigerant oil brought to the counter-pressure level goes through the wear plate 17 into the suction-pressure spiral nozzle 4 with the flow borehole. The refrigerant oil is routed to the counter-pressure channel 7 in the inlet region 19 with a branch for the refrigerant oil. The counter-pressure channel 7 is connected to the counter-pressure chamber 10, which, in turn, has an active connection to the back side of the orbiting spiral 12 in order to generate the corresponding counter-pressure upon the movement of the orbiting spiral 12. The refrigerant oil, which is not routed into the counter-pressure chamber 10 by means of the counter-pressure channel 7, is then further expanded in the suction-pressure spiral nozzle 4 and correspondingly in the suction-pressure throttle region 24 and reaches the collection area 25 of the suction-pressure spiral nozzle 4, where the refrigerant oil is transferred to the suction-pressure channel 6 at suction pressure. The refrigerant oil finally reaches the suction-pressure chamber 9 in the suction-pressure channel 6. In the suction-pressure chamber 9, the refrigerant oil with the refrigerant gas at suction-pressure level is suctioned from the suction-gas inlet and the fixed spiral and finally compressed between the spirals 11, 12, whereby the oil circuit shown here is closed. An indicated pressure adaptation of the suction pressure can take place by means of an expansion region 23 in the middle housing 18.

(13) FIG. 3 shows the oil return unit 2 in enlarged detail, wherein particularly the position of the high-pressure channel 5 is shown with emphasis. The high-pressure channel 5, which is positioned between the counter-pressure spiral nozzle 3 and the high-pressure chamber 8, is inclined from the high-pressure chamber 8 toward the counter-pressure spiral nozzle 3 at an angle α. The incline and thus the angle α is 3° to 6° in order to ensure an optimized flow of the refrigerant oil into the oil return unit 2. Particularly emphasized in the drawing is the expansion region 15 in the fixed spiral 11, wherein the expansion region 15 is designed as a type of counterbore in the cylindrical cavity 21.

(14) FIGS. 4 and 5 show views with details of the oil return unit 2 in the fixed spiral 11 with an offset supply borehole as the high-pressure channel. The supply borehole consists of a central borehole 26 and a stepped borehole 27. The central borehole 26 is designed coaxially with respect to the cylindrical cavity 21 and has a reduced diameter compared thereto. The stepped borehole 27 is offset in parallel upward in its axial position and overlaps with the central borehole 26 in the area of the notch. This area forms the connection between the stepped borehole 27 and the central borehole 26. The diameter of the central borehole 26 correlates to the cavity 29 of the spiral nozzle insert 20 of the counter-pressure spiral nozzle 3. The stepped drill hole 27 connects the high-pressure chamber 8 to the central borehole 26. The refrigerant oil thus flows from the high-pressure chamber 8, via the stepped borehole 27 and the notch area, into the central borehole 26 and into the cavity 29 of the spiral nozzle insert 20. Once the cavity 20 is filled, the refrigerant oil flows from the cavity 29, through the overflow openings 28 in the wall of the spiral nozzle insert 20, into the collection area 25, which is formed between the outer side of the spiral nozzle insert 20 and the outer wall of the cylindrical cavity 21, before it enters the spiral groove. The arrangement, which is offset in height from above to below, of the high-pressure chamber 8, the stepped borehole 27, and the central borehole 26 leads to support of the oil flow from the high-pressure chamber 8 into the counter-pressure spiral nozzle 3 by means of the height difference.

LIST OF REFERENCE NUMERALS

(15) 1 Scroll compressor 2 Oil return unit 3 Counter-pressure spiral nozzle 4 Suction-pressure spiral nozzle 5 High-pressure channel 6 Suction-pressure channel 7 Counter-pressure channel 8 High-pressure chamber 9 Suction-pressure chamber 10 Counter-pressure chamber 11 Fixed spiral 12 Orbiting spiral 13 Inlet region, counter-pressure spiral nozzle 14 Counter-pressure throttle region 15 Expansion region, fixed spiral 16 Collection area 17 Wear plate with flow borehole 18 Middle housing 19 Inlet region with branch 20 Spiral nozzle insert 21 Cylindrical cavity in fixed spiral 22 Cylindrical cavity in middle housing 23 Expansion region, middle housing 24 Suction-pressure throttle region 25 Collection area 26 Central borehole 27 Stepped borehole 28 Overflow opening 29 Cavity