JP7268163B2 - liquid cooled gas compressor - Google Patents

Description

The present invention relates to liquid-cooled gas compressors.

2. Description of the Related Art Among gas compressors that suck gas such as air and discharge high-pressure gas by means of a positive displacement compression mechanism, a liquid-cooled gas compressor that supplies a cooling liquid to a compression space is well known.

The purpose of supplying the coolant is to lubricate the compression mechanism, seal against gas leakage between the compression mechanisms, and cool the gas whose temperature rises due to compression. Conventionally, cooling liquid cooled by a heat exchanger is supplied to the compressor body to cool the compressed gas and improve efficiency.

For example, in Patent Document 1, a cooling path separate from the conventional cooling path is provided, and the amount of water passing through each cooling path is adjusted according to the detected difference between the feed water temperature and the ambient temperature, thereby reducing the power consumption required for cooling the compressor. We are trying to reduce it.

Specifically, part of the cooling water supplied to the compressor main body is further cooled by the heat exchanger of the refrigeration cycle and supplied to the sliding bearing. The circulating water to be supplied to the sliding bearing is cooled not only by the air-cooling heat exchanger but by using a refrigeration cycle. This minimizes the energy required for cooling the circulating water and enables highly reliable operation even under high ambient temperature conditions.

JP 2010-43589 A

Patent Literature 1 does not mention the problem of further improving the cooling effect by supplying cooling liquids of at least two different temperatures to the compressor body and technical means for solving the problem. .

An object of the present invention is to further improve the cooling effect by supplying coolants having at least two different temperatures to the compressor body.

A liquid-cooled gas compressor of one aspect of the present invention is a liquid-cooled gas compressor having a compressor body, a first heat exchanger, and a second heat exchanger, a first cooling path that supplies a first coolant having a first temperature to a first location of the compressor body passing through the heat exchanger of the first heat exchanger and the second and a second cooling path that supplies a second cooling liquid having a second temperature lower than the first temperature and passing through the heat exchanger of the compressor body to a second location of the compressor body. and

A liquid-cooled gas compressor according to one aspect of the present invention is a liquid-cooled gas compressor having a compressor body and a single heat exchanger, wherein a first a first cooling path that supplies a first coolant having a temperature to a first location of the compressor body; and a second cooling path for supplying two coolants to a second portion of the compressor body.

According to one aspect of the present invention, it is possible to further improve the cooling effect by supplying cooling liquids having at least two different temperatures to the compressor body.

It is a figure which shows the structure of the liquid cooling type gas compressor of related technology. 1 is a diagram showing the configuration of a liquid-cooled gas compressor of Example 1. FIG. It is a rotor horizontal direction sectional view of a screw compressor. It is a rotor perpendicular direction sectional view of a screw compressor. FIG. 2 is an exploded view of the screw compressor in the radial direction of the rotor; It is a pressure diagram of a compressor. FIG. 5 is a diagram showing the configuration of a liquid-cooled gas compressor of Example 2;

First, a related art liquid-cooled gas compressor will be described with reference to FIG.
Since the temperature of the gas sucked into the compressor main body 1 rises during the compression process, the cooling liquid is supplied to cool the gas. The cooled compressed gas is discharged while being mixed with the cooling liquid, and separated into the gas and the cooling liquid in the separator 2 . After that, the cooling liquid is cooled to a lower temperature than the compressed gas during the compression process in the heat exchanger 3 using the cooling fan 4, and is supplied through the cooling path 5 during the compression process to cool the compressed gas again. .
In this way, in the liquid-cooled gas compressor of the related art, a low-temperature cooling liquid cooled by a heat exchanger is supplied to the compressor main body to cool the compressed gas and achieve high efficiency.

Generally, one heat exchanger is used for cooling in order to save energy and space, and the temperature of the cooling liquid is determined by the specifications of the mounted heat exchanger. In addition, the coolant that has passed through the heat exchanger is often supplied to the compressor main body through a single cooling path without being branched. be done.

In the following embodiments, the paths of the cooling liquid supplied to the compressor main body are branched, each cooling liquid is cooled, and the cooling liquid is not returned to the same path, but is individually supplied to the compressor main body through separate paths.

As a result, in the related art, the cooling liquid is supplied at one temperature, whereas in the embodiment, cooling liquids with different temperatures can be individually supplied to the compressor main body, and the compressed gas can be cooled with high efficiency. This leads to a significant improvement in compressor performance.
An embodiment will be described below with reference to the drawings.

A liquid-cooled gas compressor according to the first embodiment will be described with reference to FIG.
The most different configuration of the first embodiment from the liquid-cooled gas compressor of the related art is that it has two heat exchangers 6 and 8, two cooling paths 7 and 9, and the compression It is a point to supply to two places of a machine main body, respectively.

One coolant flow passes through one heat exchanger 6 and is supplied to the compressor body via a cooling path 7 . Another coolant flow passes through the heat exchanger 6, then through the heat exchanger 8, through a cooling path 9 separate from the cooling path 7, and is supplied to a location different from the coolant. .

Assuming that the same cooling fan 4 is used in the compressor of this embodiment and the related technology and the amount of cooling fluid does not change, the cooling fluid in the configuration of the first embodiment has a lower temperature and a higher temperature than the compressor of the related technology. It is possible to cool the object to two different temperatures.

For example, assume that the total amount of coolant is 50 L/min in the system of the related art, and the heat exchanger 3 cools from 90°C to 60°C. Assuming that the amount of liquid passing through the cooling path 7 and the cooling path 9 in Example 1 is 25 L/min each, and that the total cooling capacity of the heat exchangers 6 and 8 is the same as that of the heat exchanger 3, The temperature of the cooling liquid passing through the cooling path 7 is 75°C, and the amount of liquid passing through the cooling path 9 is 45°C.

Next, the supply position of the coolant to the compressor main body in the first embodiment is shown with reference to FIGS. 3 to 5. FIG.
3 is a horizontal sectional view of the rotor of the screw compressor, FIG. 4 is a vertical sectional view of the rotor taken along the arrow line II--II in FIG. 3, and FIG. 5 is a developed view in the radial direction of the rotor.

The compressor main body 1 is configured by housing a male rotor 14 and a female rotor 15 in a compressor casing 12 and a discharge casing 13 . The compressor main body 1 sucks gas by rotating the rotor with a drive source connected to either the male rotor 14 or the female rotor 15 . The gas passes through the suction path 16 and is trapped in the rotor tooth space, and as the rotor rotates further, the tooth space becomes smaller and the gas is compressed. After the gas is compressed to a predetermined compression ratio, it passes through the discharge path 17 and is discharged.

In a liquid-cooled screw compressor, cooling liquid is supplied during the process of shrinking the tooth space to cool the gas. In the first embodiment, the low-temperature coolant is supplied to the supply port 19 immediately after the suction completion position 18 , and the high-temperature coolant is supplied to the supply port 21 before the discharge start position 20 .

Assuming that the total cooling capacity of the heat exchanger is the same, the cooling effect is compared between the case of supplying cooling liquid of one temperature in the related art and the case of supplying cooling liquids of different temperatures separately in Example 1.

FIG. 6 is used to compare cooling effects. FIG. 6 is a finger pressure diagram showing the operating state of the compressor, in which the horizontal axis indicates the volume V of the compressor body and the vertical axis indicates the pressure P. As shown in FIG.

In the finger pressure diagram, 22 indicates a suction start position, 18 indicates a suction completion position, 20 indicates a discharge start position, and 23 indicates a discharge completion position.

The temperature of the gas rises as the compression process progresses. The cooling liquid is supplied at the supply port 24 where the process has progressed. In Example 1, since the coolant is cooler than in the related art schemes, it is possible to supply the supply port 19 earlier in the compression process than at position 24 .

As a result, since the cooling liquid at a lower temperature than the system of the related art can be supplied at an early stage of the compression process, the polytropic index becomes small, and the line from 18 to 20 showing the compression process changes from the dotted line L1 to the solid line L2. Become.

In the latter half of the compression process, high-temperature coolant is supplied, but at that time, the compressed gas is in a very high temperature state compared to the coolant, so even the high-temperature coolant is sufficiently cooled. Is possible. Also, since the supply port 21 for supplying the high-temperature side cooling liquid is in the latter half of the compression process, the cooling liquid has a short time to cool the gas, and does not greatly affect the lines 18 to 20 indicating the compression process.

The area surrounded by lines in the acupressure diagram indicates the power required for compression. This leads to a reduction in compression power.

If the temperature of the coolant on the low temperature side is not lower than the gas temperature during the compression process, a sufficient cooling effect cannot be obtained. (Control valve) 10 adjusts the amount of coolant on the low temperature side. For example, when the compressed gas temperature is 10 degrees higher than the ambient temperature at the position where the low-temperature coolant is supplied, the value measured by the temperature sensor 11 for the low-temperature side coolant is below the ambient temperature +10 degrees by feedback control. Change the solenoid valve opening.

In FIG. 2, by using two heat exchangers and separate cooling paths, two different temperatures are supplied to the compressor main body. It is also possible to supply coolants of different temperatures as described above.

A liquid-cooled gas compressor according to a second embodiment will be described with reference to FIG.
The point in which the second embodiment differs from the first embodiment in terms of configuration is that it uses a heat exchanger having multiple paths and a branch on the way, instead of using two heat exchangers. As an example, consider the case of using a two-pass heat exchanger that has a branch port after passing through one pass.

One coolant flow enters the heat exchanger 25 , passes through the first path 251 , exits from the first branch 252 , and is supplied to the compressor body 1 via the cooling path 7 .

Another coolant flow enters heat exchanger 25 through first pass 251 and second pass 253 before exiting second branch 254 via cooling path 9 and into the compressor. Supply to the main body 1.

As for the supply ports, the high-temperature coolant that has passed through only the first path 251 is supplied to the supply port 21 on the discharge side, and the low-temperature coolant that has passed through the first and second paths 251 and 253 is supplied to the suction side. Feed into port 19 (see FIG. 3).

In the case of the second embodiment, a branch port is provided for each path of the heat exchanger, and three or more different temperatures can be cooled without adding a new heat exchanger except for the supply route to the compressor. Liquid can be supplied.

According to the above-described embodiment, unlike the conventional supply of cooling liquid at one temperature, cooling liquids of different temperatures can be individually supplied to the compressor main body, enabling highly efficient cooling of the compressed gas and compression. This leads to a significant improvement in machine performance.

1: Compressor body 2: Separator 3: Heat exchanger 4: Cooling fan 5: Coolant supply path to compressor body 6: First heat exchanger 7: High temperature side coolant supply to compressor body Route 8: Second heat exchanger 9: Supply route of low temperature side coolant to compressor body 10: Control valve 11: Temperature sensor 12: Compressor casing 13: Discharge casing 14: Male rotor 15: Female rotor 16: Suction Path 17: Discharge path 18: Suction completion position 19: Low temperature side coolant supply port 20: Discharge start position 21: High temperature side coolant supply port 22: Suction start position 23: Discharge completion position 24: Related technology Coolant supply port L1 in cooling system: Related technology Compression process L2 in cooling system: Compression process 25 of embodiment 1: Heat exchanger

Claims (7)

a compressor body;
a first heat exchanger;
A liquid-cooled gas compressor comprising a second heat exchanger,
a first cooling path that passes through the first heat exchanger and supplies a first coolant having a first temperature to a first location of the compressor body;
supplying a second coolant having a second temperature lower than the first temperature through the first heat exchanger and the second heat exchanger to a second location of the compressor body; a second cooling path;
has
The compressor main body is
a discharge-side supply port for the first cooling liquid provided on the gas discharge side ;
a suction-side supply port for the second cooling liquid provided on the gas suction side ;
the first portion of the compressor body corresponds to the discharge-side supply port,
the second portion of the compressor body corresponds to the suction side supply port,
supplying the second cooling liquid to the suction side supply port in the first half of the compression process in the compressor main body;
A liquid-cooled gas compressor, wherein the first cooling liquid is supplied to the discharge-side supply port in the second half of the compression process when the temperature of the compressed gas is higher than that of the first cooling liquid. the compressor body has a male rotor and a female rotor housed in a casing;
2. The liquid-cooled gas compressor according to claim 1, wherein the discharge-side supply port and the suction-side supply port are provided in the male rotor and the female rotor, respectively. A control valve and a temperature sensor are provided in the second cooling path,
The second cooling liquid is controlled by the control valve so that the second temperature of the second cooling liquid measured by the temperature sensor is equal to or lower than the temperature of the compressed gas during the compression process in the compressor main body. 2. The liquid-cooled gas compressor according to claim 1, wherein the liquid amount of is adjusted. a compressor body;
A liquid-cooled gas compressor comprising a single heat exchanger,
a first cooling path passing through the heat exchanger and supplying a first coolant having a first temperature to a first location of the compressor body;
a second cooling path passing through the heat exchanger and supplying a second coolant having a second temperature lower than the first temperature to a second location of the compressor body;
has
The compressor main body is
a discharge-side supply port for the first cooling liquid provided on the gas discharge side ;
a suction-side supply port for the second cooling liquid provided on the gas suction side ;
the first portion of the compressor body corresponds to the discharge-side supply port,
the second portion of the compressor body corresponds to the suction side supply port,
supplying the second cooling liquid to the suction side supply port in the first half of the compression process in the compressor main body;
A liquid-cooled gas compressor, wherein the first cooling liquid is supplied to the discharge-side supply port in the second half of the compression process when the temperature of the compressed gas is higher than that of the first cooling liquid. The heat exchanger is
a first pass;
a second path connected to the first path;
a first branch;
a second branch, and
After passing through the first path, the cooling liquid entering the heat exchanger exits from the first branch port, passes through the first cooling path, and is supplied to the discharge side of the compressor main body. fed to the mouth,
After passing through the first pass and the second pass, the cooling liquid entering the heat exchanger exits from the second branch port and passes through the second cooling path to the compression 5. The liquid-cooled gas compressor according to claim 4, wherein the gas is supplied to the suction side supply port of the machine body. the compressor body has a male rotor and a female rotor housed in a casing;
5. The liquid-cooled gas compressor according to claim 4, wherein the discharge-side supply port and the suction-side supply port are provided in the male rotor and the female rotor, respectively. A control valve and a temperature sensor are provided in the second cooling path,
The second cooling liquid is controlled by the control valve so that the second temperature of the second cooling liquid measured by the temperature sensor is equal to or lower than the temperature of the compressed gas during the compression process in the compressor main body. 5. The liquid-cooled gas compressor according to claim 4, wherein the liquid amount of is adjusted.

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