JPH0674173A - Two-stage oil cooled compressor - Google Patents

Abstract

PURPOSE:To increase a cooling efficiency by cooling liquid in a compressor main body to increase the performance of a compressor by providing an oil feed line to feed oil from oil sumps to oil-fill locations through an oil cooler and a cooling liquid feed line to jet the cooling liquid. CONSTITUTION:A two-stage oil cooled compressor is provided with a first oil separation and recovery device 7 installed in an intermediate flow line 6 between first and second stage compressor main bodies 1 and 5 and a second oil separation and recovery device 10 installed in a flow line 9 connected to a discharge port of the second stage compressor main body 5. Also an oil feed line 16 to feed oil from oil sumps 11 and 12 under the first and second oil separation and recovery devices 7 and 10 to oil-fill locations in the first and second compressor main bodies 1 and 5 through an oil pump 13, an oil filter 14, and an oil cooler is installed. In addition, a cooling liquid feed line 23 for injecting refrigerant liquid is installed in the intermediate flow line between the first oil separation and recovery device 7 and the second compressor main body 5. Thus cooling liquid is accumulated sufficiently for long time in the compressor main body, and the heat of vaporization of the cooling liquid can be used effectively.

Description

Detailed Description of the Invention

[0001]

The present invention is applied to, for example, refrigerators, heat pump LNG compressors, and water injection type gas compressors.
The present invention relates to a stepped oil-cooled compressor.

[0002]

2. Description of the Related Art Conventionally, a single-stage oil-cooled screw compressor in which a cooling liquid is injected into a gas compression space is known (Japanese Patent Laid-Open No. 60-114490). This compressor is
This is intended to cool the gas compression space portion by utilizing the heat of vaporization of the cooling liquid.

[0003]

In the above-mentioned conventional device,
Since it is a single-stage compressor, the cooling liquid injected into the gas compression space stays in this space for a very short time and vaporizes after being discharged from the compressor. As a result, cooling in the compressor body due to the injection of cooling liquid becomes insufficient,
There is a problem that the intended performance improvement effect of the compressor cannot be obtained. The present invention has been made to solve the above-mentioned conventional problems, and a two-stage oil-cooled compressor capable of improving the performance of the compressor by increasing the cooling efficiency of the cooling liquid in the compressor body. Is to provide.

[0004]

In order to solve the above-mentioned problems, the present invention has a second stage having a first stage compressor body and a rotor adapted to rotate coaxially with the rotor of the first stage compressor body. Stage compressor body, a first oil separating and collecting device provided in an intermediate flow path between the first and second stage compressor bodies, and a second oil provided in a flow path following the discharge port of the second stage compressor body A separation / recovery device, and an oil supply flow path for supplying oil from an oil sump portion below the first and second oil separation / recovery devices to at least an oil cooler in the first and second compressor bodies. , 1st oil separation and recovery device and 2nd
A cooling liquid supply flow passage for injecting the cooling liquid is provided in the intermediate flow passage portion between the compressor body and the compressor body.

[0005]

With the above structure, the residence time of the cooling liquid in the compressor body is sufficiently long, and the compressed gas is cooled after the oil heated in the first stage compressor body is separated. Only the heat of vaporization of the cooling liquid is used.

[0006]

An embodiment of the present invention will be described below with reference to the drawings. 1 and 2 show a refrigerator to which a two-stage oil-cooled screw compressor according to the present invention is applied. A first-stage compressor body 1, a screw rotor 2 and a rotor of the first-stage compressor body 1 are shown. There is provided a second stage compressor body 5 having a screw rotor 4 which is coaxially rotated with the shaft 3 in common. A first oil separation / collector 7 is provided in the intermediate flow path 6 between the first and second stage compressor bodies 1 and 5, and a second oil separation and recovery device 7 is provided in the flow path 9 following the discharge port 8 of the second stage compressor body 5. An oil separator / collector 10 is provided. The first and second compressor bodies 1 and 5 are connected to the oil sump portions 11 and 12 below the first and second oil separation and recovery units 6 and 10 via an oil pump 13, an oil filter 14, and an oil cooler 15. An oil supply passage 16 for supplying oil is connected to the oil-filling points such as a bearing, a shaft seal portion, and a gas compression space portion, which are not shown.

Further, a passage 21 is connected from the upper portion of the second oil separation / recovery device 10 through the condenser 17, the expansion valve 18 and the evaporator 19 to the suction port 20 of the first stage compressor body 1. . Liquid receiving portion 22 for storing the refrigerant liquid condensed in the condenser 17
A cooling liquid supply flow path 23 for guiding the refrigerant liquid from here to the portion of the intermediate flow path 6 between the first oil separation / recovery device 7 and the second stage compressor body 5 is connected. This cooling liquid supply channel 2
Nozzle 24 is provided at the tip of the connecting portion of the intermediate flow path 3 to the intermediate flow path 6, and the refrigerant liquid is injected into the intermediate flow path 6. In FIG. 1, the rotor shaft 3 is shown with the middle part omitted, but it is actually continuous from the first-stage compressor body 1 to the second-stage compressor body 5, and It means that they are continuous.

Next, the operation of the device having the above structure will be described. First, the refrigerant gas sucked from the suction port 20 of the first-stage compressor body 1 is compressed while being injected with oil for cooling, sealing, and lubrication from the oil supply flow passage 16, and the intermediate gas is flowed together with this oil. 6 is discharged. In the intermediate flow path 6, the first oil separation / recovery device 7 separates the oil whose temperature is raised by the compression heat from the refrigerant gas, and collects the oil in the oil sump 11. The oil injected into the bearing and the shaft seal portion of the first-stage compressor body 1 is finally compressed along with the compressed refrigerant gas into the intermediate passage 6
And is collected in the oil sump 11.

Further, on the outlet side of the first oil separating and collecting unit 7,
The refrigerant liquid guided from the liquid receiving portion 22 of the condenser 17 through the cooling liquid supply flow path 23 is jetted, and the refrigerant liquid is sucked into the second stage compressor body 5 together with the compressed and heated refrigerant gas. Again, the refrigerant gas is compressed while being injected with oil from the oil supply channel 16, the refrigerant liquid is vaporized in this process, and then the oil is discharged from the discharge port 8 together with the compressed refrigerant gas, and the second oil separation and recovery is performed. It reaches the vessel 10. Here, the residence time of the injected refrigerant gas until reaching the discharge port is sufficiently long, during which the refrigerant liquid is completely vaporized and
Since the oil whose temperature has been raised in the first-stage compressor body 1 is separated in the first oil separation / collector 7, the heat of vaporization is not used for cooling the oil from the first-stage compressor body 1, It will be efficiently used for cooling the compressed refrigerant gas.

In the second oil separation and recovery device 10, the refrigerant gas and the oil are separated, the oil is recovered in the oil sump 12, and the refrigerant gas is sent out to the condenser 17 through the flow path 21. The oil injected into the bearing and the shaft seal portion of the second stage compressor body 5 is finally discharged into the flow passage 9 together with the compressed refrigerant gas and collected in the oil sump portion 12 as in the above. In the condenser 17, as is well known, the refrigerant gas is condensed to raise the temperature of an external heat source (high temperature side) not shown, and the condensed liquid is temporarily stored in the liquid receiving section 22, while the expansion valve 18 and the evaporator 19 are The external heat source (low temperature side) is cooled by evaporating the refrigerant liquid at. The refrigerant gas evaporated in the evaporator 19 is sucked into the first stage compressor body 1 and then circulates in the gloss loop in the same manner as above.

The oil in the oil sumps 11 and 12 is supplied to the oil pump 1.
3, After passing through the oil filter 14 and being cooled by the oil cooler 15, the oil is sent to the above-mentioned lubrication point, and thereafter circulated and used similarly. A part of the refrigerant liquid in the liquid receiving section 22 is jetted into the intermediate flow path 6 via the cooling liquid supply flow path 23 and the nozzle 24 as described above. In this way, the first stage compressor body 1
Then, the oil is cooled, and the oil whose temperature has risen at the place of exiting the first-stage compressor body 1 is separated from the refrigerant gas, so that only the refrigerant gas to be finally cooled remains in the intermediate flow path 6. . After that, by injecting the refrigerant liquid into the intermediate flow path 6, the residence time until the refrigerant liquid is discharged from the second compressor main body 5 is sufficiently long to completely vaporize the refrigerant liquid and vaporize it. The heat is not used to cool the oil, but is effectively used for a sufficiently long time to cool the refrigerant gas to be compressed. As a result, the performance of the compressor can be improved.

By the way, a flow rate control valve is provided in the refrigerant liquid supply passage 23 so that the amount of the refrigerant liquid injected into the intermediate passage 6 can be adjusted, and the discharge gas temperature can be adjusted to control the capacity during cooling. You may form in. Although the screw compressor has been described in the above embodiment, the present invention is not limited to this, and is not limited to a refrigerator as an application example. Further, the cooling liquid supply flow path for supplying the cooling liquid to the intermediate flow path is not limited to the one from the liquid receiving section 22, but may be one in which cooling water is jetted.

[0013]

As is apparent from the above description, according to the present invention, the second stage having the first stage compressor body and the rotor adapted to rotate coaxially with the rotor of the first stage compressor body. A compressor body, a first oil separation / collector provided in an intermediate flow passage between the first and second stage compressor bodies, and a second oil separation provided in a flow passage that follows the discharge port of the second stage compressor body. A collector and an oil supply flow path for supplying oil from an oil sump below the first and second oil separation / collectors to an oil injection point in the first and second compressor bodies via at least an oil cooler; A cooling liquid supply passage for injecting a cooling liquid is provided in the intermediate passage portion between the first oil separation / recovery device and the second compressor body.

Therefore, by cooling the oil in the main body of the first stage compressor and separating the oil whose temperature has risen from the main body of the first stage compressor from the gas to be compressed, the intermediate flow passage is finally cooled. By leaving only the gas to be compressed, and then injecting the cooling liquid into the intermediate flow passage, the residence time until the cooling liquid is discharged from the second compressor main body is sufficiently long to completely remove the cooling liquid. Evaporate and allow the heat of vaporization not to be used to cool the oil, but to be used effectively for a sufficiently long time to cool the compressed refrigerant gas, thus improving the performance of the compressor There is an effect that it becomes possible.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a refrigerator to which a two-stage oil-cooled compressor according to the present invention is applied.

FIG. 2 is a schematic cross-sectional view showing a part of the two-stage oil-cooled compressor shown in FIG.

[Explanation of symbols]

 1 1st-stage compressor main body 5 2nd-stage compressor main body 6 Intermediate flow path 7 1st oil separation and recovery device 8 Discharge port 9 Flow path 10 2nd oil separation and recovery device 11, 12 Oil reservoir 15 Oil cooler 16 Oil Supply channel 23 Coolant supply channel

Claims (1)

[Claims] 1. A first-stage compressor body, a second-stage compressor body having a rotor adapted to rotate coaxially with the rotor of the first-stage compressor body, and between the first and second-stage compressor bodies. First oil separation and recovery device provided in the intermediate flow path of the second, the second oil separation and recovery device provided in the flow path following the discharge port of the second stage compressor body, and the lower part of the first and second oil separation and recovery devices An oil supply passage for supplying oil from the oil sump portion of the first oil compressor to at least the oil cooler in the first and second compressor bodies, the first oil separation and recovery device, and the second oil recovery device.
A cooling liquid supply flow passage for injecting a cooling liquid is provided in an intermediate flow passage portion between the compressor main body and the compressor main body, which is characterized in that
Stepped oil-cooled compressor.