JP2016008780A - Oil separation unit and screw compressor using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oil separation unit capable of restricting the reduction in oil separation efficiency even when a refrigerant gas pressure taking-out port is provided in the oil separation unit.SOLUTION: An oil separation unit of the invention comprises: an outer cylinder; an inner cylinder positioned inside of the outer cylinder; an introduction flow passage through which refrigerant is introduced so as to revolve about the outer cylinder and proceed along an internal surface of the outer cylinder in a circumferential direction; a refrigerant gas space positioned above the inner cylinder to store the refrigerant gas; a refrigerant gas flow passage connected to the refrigerant gas space to drain the refrigerant gas from the refrigerant gas space; and a refrigerant gas pressure taking-out port connected to the refrigerant gas space. The refrigerant gas entered from the introduction flow passage is separated into the refrigerant gas and oil by revolving and descending along the internal surface of the outer cylinder; the separated refrigerant gas enters the inside of the inner cylinder from the bottom edge of the inner cylinder to ascend, and then drains from the refrigerant gas flow passage via the refrigerant gas space; and the separated oil descends along the internal surface of the outer cylinder.

Description

  The present invention relates to an oil separator and a screw compressor using the oil separator.

  In the refrigeration cycle of the screw refrigerator, the refrigerant gas discharged from the screw compressor contains lubricating oil. At this time, if the amount of oil discharged is excessive or the amount returned to the compressor is small, the amount of oil necessary for lubrication may be insufficient, leading to events such as galling or locking of the compressor. There is. Further, when lubricating oil is sent to a container such as a condenser or an evaporator on the downstream side, heat transfer may be hindered and sufficient performance may not be exhibited. In order to prevent such an event, an oil separator is provided on the discharge side of the compressor to sufficiently separate the refrigerant gas and the lubricating oil, and a refrigerant gas circuit to the condenser and a lubricating oil circuit to return to the compressor are formed. Is common.

  There are several types of oil separators having different structures depending on the method of separating oil. For example, those that rotate the inside of a vertical cylindrical cylinder to centrifuge oil droplets, those that provide fine nets (demisters) knitted with fibrous metal wires to separate oil, and baffles that have many small holes Some of them utilize the action of oil droplets adhering to the plate by collision. The lubricating oil separated by these means is temporarily stored in the lower part of the container and returned to the compressor using a differential pressure or a hydraulic pump.

  In addition, there are two types of oil separators, one is an independent container, and the other is an integral unit attached to a compressor.

  Patent Document 1 discloses the structure of an oil separator that rotates and centrifuges a refrigerant. The purpose of this oil separator is to increase the oil separation efficiency by slowing the flow velocity after turning.

Japanese Patent Laid-Open No. 2005-180808

  In such an oil separator, a safety device such as a safety valve that discharges the refrigerant when the refrigerant gas pressure exceeds a certain value, a pressure sensor that detects the pressure in the container, and the like may be attached. In order to attach these devices, it is necessary to insert a joint such as a seat and a nozzle by inserting them into the cylindrical body, so that an uneven portion and a protrusion are formed on the inner surface of the cylindrical body.

  In the case of an oil separator that performs centrifugal separation by swirling the inside of a vertical cylindrical body, if there is a concave portion inside the outer cylinder of the swivel portion, it may be transmitted through the wall surface, leading to oil accumulation or oil clogging. On the other hand, if there are convex portions or protrusions in the swivel portion, it becomes a resistance and the swivel speed is slowed down. As a result, the oil separation efficiency is lowered, and the lubricating oil flows out together with the refrigerant gas to a condenser or the like on the downstream side.

  This invention makes it a subject to provide the oil separator which suppressed the fall of oil separation efficiency, even if it is a case where a refrigerant gas pressure taking-out port is provided in an oil separator.

  An oil separation device according to the present invention includes an outer cylinder, an inner cylinder positioned inside the outer cylinder, an introduction flow path for allowing the refrigerant to flow around the inner wall surface of the outer cylinder in the circumferential direction, and the inner cylinder A refrigerant gas space that is located above and stores refrigerant gas; a refrigerant gas passage that is connected to the refrigerant gas space and flows out of the refrigerant gas space; and a pressure outlet for the refrigerant gas connected to the refrigerant gas space; The refrigerant flowing in from the introduction path is separated into refrigerant gas and oil by swirling and descending the inner wall surface of the outer cylinder, and the separated refrigerant gas flows into the inner cylinder from the lower end portion of the inner cylinder. Then, it flows out from the refrigerant gas flow path via the refrigerant gas space, and the separated oil flows down along the inner wall surface of the outer cylinder.

  ADVANTAGE OF THE INVENTION According to this invention, even if it is a case where a refrigerant gas pressure taking-out port is provided in an oil separator, the oil separator which suppressed the fall of oil separation efficiency can be provided.

1 is a diagram illustrating the structure of an oil separator according to Embodiment 1. FIG. The figure which shows the structure of the oil separator of Example 2. FIG. The figure which shows the structure of the oil separator of Example 3. FIG. The figure which shows the structure of a ring-shaped member and an inner cylinder. The figure which shows the structure of a ring-shaped member and an inner cylinder.

  An oil separation device according to the present invention includes an outer cylinder, an inner cylinder positioned inside the outer cylinder, an introduction flow path for allowing the refrigerant to flow around the inner wall surface of the outer cylinder in the circumferential direction, and the inner cylinder A refrigerant gas space that is located above and stores refrigerant gas; a refrigerant gas passage that is connected to the refrigerant gas space and flows out of the refrigerant gas space; and a pressure outlet for the refrigerant gas connected to the refrigerant gas space; The refrigerant flowing in from the introduction path is separated into refrigerant gas and oil by swirling and descending the inner wall surface of the outer cylinder, and the separated refrigerant gas flows into the inner cylinder from the lower end portion of the inner cylinder. Then, it flows out from the refrigerant gas flow path via the refrigerant gas space, and the separated oil flows down along the inner wall surface of the outer cylinder. Centrifugation is performed by providing a space (refrigerant gas space) in the refrigerant gas portion after the separation of the refrigerant, instead of providing a pressure outlet in the outer cylinder that turns the refrigerant and separates it into refrigerant gas and lubricating oil. As a result, the concave and convex portions and the projections in the cylindrical body that hinder the oil flow are not increased, and the decrease in the oil separation efficiency can be suppressed. Further, since the pressure outlet is connected to the refrigerant gas space after the separation of the lubricating oil by turning, the stable refrigerant gas pressure can be taken out and the stable refrigerant gas pressure can be detected. Further, the problem that oil is accumulated on the inner surface of the nozzle and accurate pressure detection cannot be performed can be solved.

  The oil separator according to this embodiment will be described with reference to FIGS. FIG. 1 is a configuration diagram of an oil separator according to this embodiment.

  The oil separator of the present embodiment is connected to a screw compressor having a male rotor and a female rotor that rotate while meshing with each other and the rotation shafts are substantially parallel to each other, and refrigerant discharged from the compression working chamber is introduced. The refrigerant flows from the flow path and separates the refrigerant into refrigerant gas and oil.

  Refrigerant gas containing lubricating oil discharged from the compressor flows into the cylinder from the inlet nozzle 5 of the oil separator and swirls through the gap between the outer cylinder 1 and the inner cylinder 2. As the refrigerant turns, it is centrifuged into refrigerant gas and lubricating oil, and only the refrigerant gas passes through the central portion of the inner cylinder 2 and is discharged from the upper refrigerant flow path 7.

  On the other hand, the lubricating oil adhering to the outer cylinder 1 travels through the outer cylinder 1 and accumulates below the oil separator. The accumulated lubricating oil is sent to a device such as an oil cooler to be cooled, removed foreign matter by a filter or the like, and then returned to the compressor to lubricate the rotating portion and the like.

  In order to detect the pressure of the refrigerant gas from the oil separator having such a structure, if a pipe for taking out the pressure is inserted into the outer cylinder 1 of the oil separator, the centrifugal separator is obstructed and the performance is deteriorated. There is also the possibility of oil clogging in the inserted pipe. Therefore, a ring-shaped steel plate 4 is attached between the inner cylinder 2 and the end plate 3 to provide a refrigerant gas space 9 in which only the refrigerant gas after the refrigerant swirls and the lubricating oil is separated is accumulated. By providing the refrigerant flow path 7 and the pressure port 6 in the end plate 3 in the space 9, even if the oil separator is provided with a pressure extraction port for the refrigerant gas, the refrigerant gas is suppressed while suppressing a decrease in oil separation efficiency. Can be detected.

  As described above, the oil separator according to this embodiment includes the end plate 3 disposed at the upper end of the outer cylinder 1, the ring-shaped member 4 connected to the inner wall of the outer cylinder 1, and the ring-shaped member 4. A refrigerant gas space 9 is formed by the end plate 4 and the ring-shaped member.

  Specifically, as shown in FIG. 4, a general pipe material 2 is used for the inner cylinder 2, and the pipe material 2 is attached to a steel material 4 processed into a ring shape. By attaching these integrally formed pipe material 2 and steel material 4 to the outer cylinder 1 at a position away from the end plate 3, a refrigerant gas space 9 after being separated from the lubricating oil is formed.

  Further, as shown in FIG. 5, the inner cylinder 2 and the ring-shaped steel plate 4 may be integrally formed by drawing. The welding work between the inner cylinder 2 and the ring-shaped steel plate 4 is not necessary, and the resistance can be reduced by the R portion, and effects such as loss reduction and noise reduction can be obtained.

  Next, Example 2 will be described with reference to FIG. In the present embodiment, the pressure take-out port 6 is arranged so that the center axis of the pressure take-out port 6 does not overlap the center axis of the inner tube 2 (the pressure take-out port 6 is arranged at a position shifted from the inner tube 2). With such a configuration, the influence of the swirling flow can be suppressed, and a stable pressure can be detected.

  Further, the refrigerant gas flow path 7 is arranged so that the central axis of the refrigerant gas flow path 7 does not overlap the central axis of the inner cylinder 2 (the refrigerant gas flow path 7 is arranged at a position shifted from the inner cylinder 2). With such a configuration, the turning of the refrigerant flowing out of the refrigerant gas flow path 7 can be further suppressed.

  Here, by reducing the diameter of the hole processed in the ring-shaped steel plate 4, it is possible to further suppress the influence of the swirling of the refrigerant on the refrigerant gas flow path 7 and the pressure outlet 6.

  Next, Example 3 will be described with reference to FIG. In the present embodiment, the outer cylinder 1 has an end plate 3 at the upper end, the refrigerant gas flow path 7 is connected to the end plate 3, and the pressure outlet 6 is connected to the side surface of the outer cylinder 1. By providing the pressure port 6 in the outer cylinder 1 in the refrigerant flow direction and the lateral direction, pulsation of the refrigerant gas and the like can be suppressed.

DESCRIPTION OF SYMBOLS 1 ... Outer cylinder 2 ... Inner cylinder 3 ... End plate 4 ... Ring-shaped steel plate 5 ... Inlet nozzle (introduction flow path)
6 ... Pressure port (Pressure outlet)
7 ... Refrigerant flow path 8 ... Lubricating oil flow path 9 ... Space (refrigerant gas space)

Claims (5)

An outer cylinder,
An inner cylinder located inside the outer cylinder;
An introduction flow path for allowing the refrigerant to flow in such a way as to turn the inner wall surface of the outer cylinder in the circumferential direction;
A refrigerant gas space that is located above the inner cylinder and in which refrigerant gas accumulates;
A refrigerant gas flow path connected to the refrigerant gas space, from which refrigerant gas flows out of the refrigerant gas space;
A pressure outlet for refrigerant gas connected to the refrigerant gas space;
With
The refrigerant flowing in from the introduction path is separated into refrigerant gas and oil by swirling down the inner wall surface of the outer cylinder,
The separated refrigerant gas flows into the inner cylinder from the lower end of the inner cylinder and rises, and then flows out from the refrigerant gas flow path via the refrigerant gas space,
The separated oil flows down along the inner wall surface of the outer cylinder. In claim 1,
The oil separator according to claim 1, wherein a central axis of the pressure outlet is arranged so as not to overlap a central axis of the inner cylinder. In claim 1 or 2,
The outer cylinder has an end plate at an upper end, the refrigerant gas flow path is connected to the end plate, and the pressure outlet is connected to the outer cylinder. In claim 1 or 2,
An end plate disposed at the upper end of the outer cylinder;
A ring-shaped member connected to the inner wall of the outer cylinder;
The inner cylinder connected to the ring-shaped member;
The oil separation device, wherein the refrigerant gas space is formed by the end plate, the ring-shaped member, and the outer cylinder. A male rotor and a female rotor whose rotation axes are substantially parallel and rotate while meshing with each other to form a compression working chamber;
The oil separator according to any one of claims 1 to 4, wherein the refrigerant discharged from the compression working chamber flows in from the introduction flow path and separates the refrigerant into refrigerant gas and oil;
Screw compressor equipped with.