Gas compressor

Abstract

The present invention prevents performance reduction of a cooling system and power efficiency reduction of a gas compressor caused by annual deterioration and changes of the gas compressor. The gas compressor includes a gas compressor that compresses gas, an air cooler of a liquid cooling type that performs cooling of the compressed gas discharged from the gas compressor, and an oil cooler of a liquid cooling type that cools lubricating oil that lubricates / cool the gas compressor, a cooling medium piping system that supplies a cooling medium to the air cooler and the oil cooler, the cooling medium piping system being branched from a main piping to the air cooler and the oil cooler, temperature detectors that respectively detect a temperature of the compressed gas downstream of the air cooler and a temperature of the lubricating oil downstream of the oil cooler, and adjusting valve bodies that respectively change a flow rate of the cooling medium to the branched piping, and when the temperature of the compressed gas is above a threshold value, the opening degree of the adjusting valve bodies is changed to increase the flow rate of the cooling medium flowing in the air cooler.

Description

Technical Field

[0001] This invention relates to gas compressors, and specifically to gas compressors for regulating the amount of coolant in compressed gases and equipment. Background Technology

[0002] In compressors that compress gases (such as atmosphere), liquid-cooled gas compressors are known to use liquids (such as water or oil) as the cooling medium to cool the compressed gas and the equipment. Patent Document 1 discloses a water-cooled compressor in which the cooling medium flows through a cooler (heat exchanger) used to cool the compressed gas to a specified temperature and to cool the compressor body and other structural components, thereby exchanging heat with the compressed gas and the equipment coolant for cooling. The coolant system supplying coolant to the cooler consists of main piping and branch piping, with each branch piping connected to a specific cooler. In compressors with this structure, the hydraulic pressure is generally adjusted according to the specifications of the piping system or piping structure to ensure that a specified amount of liquid flows through each branch system.

[0003] In addition, in gas compressors, excessive temperature rise of compressed gas or lubricating oil can have adverse effects on the device. Therefore, gas compressors are known to be equipped with protective devices (such as temperature sensors and their control devices) to monitor the status and have the function of forcibly stopping the gas compressor when excessive temperature rise is detected.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: WO2020 / 012829 International Publication Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] However, there is a risk that the cooling performance of the supplied components, such as the cooler and compressor body, may deteriorate due to the usage and deterioration of the gas compressor over the years, differing from the original design values. For example, if the temperature of the compressed air discharged from a deteriorated gas compressor body rises excessively, the heat exchange rate between the cooler and the gas compressor body will also change, potentially hindering the maintenance of the gas compressor.

[0009] In addition, for example, if the flow path inside the cooler is blocked due to dirt or deposits, there is also a risk that the heat exchange rate with the cooling medium will change and that sufficient cooling performance cannot be maintained.

[0010] Furthermore, there is a risk that changes over the years may disrupt the cooling balance among the various components of the gas compressor, leading to a reduction in power efficiency.

[0011] The technology is required to prevent the performance degradation and power efficiency reduction of the cooling system caused by the annual deterioration and changes of the gas compressor.

[0012] Technical solutions for solving the problem

[0013] To address the aforementioned problems, techniques within the scope of this invention are employed. This application discloses various techniques for solving the aforementioned problems. As one example, a gas compressor is provided, comprising: a gas compressor for compressing a gas; a liquid-cooled air cooler for cooling compressed gas discharged from the gas compressor and a liquid-cooled oil cooler for cooling lubricating / cooling lubricating oil used to lubricate / cool the gas compressor; a cooling medium piping system for supplying a cooling medium to the air cooler and the oil cooler; and a control device, wherein the cooling medium piping system in the gas compressor has a main piping and branch lines from the main piping to the air cooler and the oil cooler. The air cooler and oil cooler are connected in a distribution pipe. The gas compressor includes: a gas temperature detector downstream of the air cooler that detects the temperature of the compressed gas discharged by the gas compressor; an oil temperature detector downstream of the oil cooler that detects the temperature of the lubricating oil; and regulating valves that change the flow rate of the cooling medium in the air cooler and oil cooler distribution pipes, respectively. When the temperature detector value is above a predetermined threshold, the control device changes the opening of at least one regulating valve to increase the flow rate of the cooling medium flowing in the air cooler distribution pipe.

[0014] Additionally, as another example, a gas compressor is provided, comprising: at least two compressor bodies including a low-pressure stage and a high-pressure stage; a liquid-cooled intercooler for cooling compressed gas discharged from the low-pressure stage gas compressor; a liquid-cooled aftercooler for cooling compressed gas discharged from the high-pressure stage gas compressor; a liquid-cooled oil cooler for cooling lubricating oil that lubricates / cools the low-pressure stage and high-pressure stage gas compressor bodies; a cooling medium piping system for supplying cooling medium to the intercooler, aftercooler, and oil cooler; and a control device, wherein the cooling medium piping system in the gas compressor has a main piping and branch piping for the intercooler, aftercooler, and oil cooler branching from the main piping to the intercooler, aftercooler, and oil cooler. The gas compressor includes: a first temperature detector downstream of the intercooler that detects the temperature of the compressed gas discharged from the low-pressure stage gas compressor; a second temperature detector downstream of the aftercooler that detects the temperature of the compressed gas discharged from the high-pressure stage gas compressor; an oil temperature detector downstream of the oil cooler that detects the temperature of the lubricating oil; and regulating valves that respectively change the flow rate of the cooling medium in the intercooler sub-pipe, the aftercooler sub-pipe, and the oil cooler sub-pipe. When the detection value of the oil temperature detector is lower than a predetermined threshold, the control device changes the opening of at least one regulating valve to increase the flow rate of the cooling medium flowing in the intercooler sub-pipe.

[0015] Additionally, as another example, a gas compressor is provided, comprising: at least two compressor bodies including a low-pressure stage and a high-pressure stage; a liquid-cooled intercooler for cooling compressed gas discharged from the low-pressure stage gas compressor; a liquid-cooled aftercooler for cooling compressed gas discharged from the high-pressure stage gas compressor; a liquid-cooled oil cooler for cooling lubricating oil that lubricates / cools the low-pressure stage and high-pressure stage gas compressor bodies; a cooling medium piping system for supplying cooling medium to the intercooler, aftercooler, and oil cooler; and a control device, wherein the cooling medium piping system of the gas compressor has a main piping and branch piping from the main piping to the intercooler, aftercooler, and oil cooler. The gas compressor includes: a first temperature detector downstream of the intercooler that detects the temperature of the compressed gas discharged from the low-pressure stage gas compressor; a second temperature detector downstream of the aftercooler that detects the temperature of the compressed gas discharged from the gas compressor; an oil temperature detector downstream of the oil cooler that detects the temperature of the lubricating oil; and regulating valves that respectively change the flow rate of the cooling medium in the intercooler branch pipe, the aftercooler branch pipe, and the oil cooler branch pipe. When the detection value of the oil temperature detector is lower than a predetermined threshold, the control device changes the opening degree of at least one regulating valve to reduce the flow rate of the cooling medium flowing in the oil cooler branch pipe.

[0016] Invention Effects

[0017] According to the present invention, it is possible to prevent the performance degradation and power efficiency reduction of the coolant system caused by the use of a gas compressor.

[0018] Other aspects, structures, and effects of the present invention will be described in the following description. Attached Figure Description

[0019] Figure 1 This is a schematic diagram illustrating the structure of a water-cooled gas compressor used in Embodiment 1 of the present invention and the flow of various fluids.

[0020] Figure 2 This is a flowchart illustrating the control process of the water-cooled gas compressor in Example 1.

[0021] Figure 3 This is a flowchart illustrating the control process of the water-cooled gas compressor in Example 2.

[0022] Figure 4 This is a flowchart illustrating the control process of the water-cooled gas compressor in Example 3. Detailed Implementation

[0023] Hereinafter, embodiments of the present invention will be described using accompanying drawings.

[0024] Example 1

[0025] exist Figure 1 The structure and fluid flow of the water-cooled gas compressor 1 of the embodiment are shown. First, the water-cooled gas compressor 1 includes a control device 2, a variable speed control device 3, a drive device M, a transmission device G, a primary compressor body 101 (hereinafter referred to as primary compressor 101), a secondary compressor body 102 (hereinafter referred to as secondary compressor 102), an intercooler 103, an aftercooler 104, and an oil cooler 106.

[0026] The control device 2 is electrically connected (not shown) to various components constituting the water-cooled gas compressor 1 to control its operation. In this embodiment, the control device 2 is described as implementing a functional unit based on the synergistic action of an arithmetic unit and a program, thereby performing control. However, the present invention is not limited to this; as other structural examples of the control device 2, some or all of it can be implemented using an analog structure. Furthermore, the control device 2 is not limited to being mounted on the water-cooled gas compressor 1; it can also be configured to be controlled by an external control device via a wired / wireless communication line. Additionally, it can be configured so that some control commands are input / output by an external control device, and some are input / output by the mounted control device.

[0027] The variable speed control device 3 is, for example, a power conversion device that supplies a drive source to the drive device M by changing the power frequency according to the instructions from the control device 2, thereby adjusting the speed. In this example, the case of using an inverter will be described.

[0028] The drive unit M is a device that generates mechanical energy to drive the primary compressor 101 and the secondary compressor 102 using drive energy supplied from the variable speed control device 3. This embodiment is described with reference to the use of an electric motor, but the invention is not limited to this; it can also be an internal combustion engine or a drive unit using natural energy sources such as wind or water power. Furthermore, in the case of using an internal combustion engine or a drive unit using natural energy, the variable speed control device 3 can be a transmission gear or a centrifugal pulley, etc.

[0029] The transmission device G is a mechanism that transmits driving energy from the drive device M to the primary compressor 101 and the secondary compressor 102. In this embodiment, a gear device consisting of a push gear and a bull gear is used as the transmission device G. Other structural examples of the transmission device G include chain or belt drives. Furthermore, this embodiment is described according to a structure in which one drive device M drives two compressors via the transmission device G, but the invention is not limited to this; the drive device M, independent of each compressor, can also be configured as a direct-drive type. Additionally, this embodiment uses a multi-stage compressor as an example, but the invention can also be applied to single-stage compressors.

[0030] The primary compressor 101 and the secondary compressor 102 are positive displacement compressors that operate using the driving energy of the drive unit M to generate compressed gas. In this embodiment, an oil-free screw compressor is used, but the invention is not limited to this; it can also be applied to other positive displacement compressors such as liquid-supply compressors that supply liquid (oil, water) to the compression chamber, scroll compressors, reciprocating compressors, vane compressors, and claw compressors, as well as centrifugal screw compressors such as turbine compressors. Furthermore, in the primary compressor 101 and the secondary compressor 102, the screw rotor housing is configured as a cooling jacket, and coolant (e.g., water) circulates inside to cool the compressor.

[0031] Intercooler 103 and aftercooler 104 are heat exchangers that exchange heat between compressed gas (e.g., compressed air) and coolant (e.g., water). Intercooler 103 cools the primary compressed air discharged from primary compressor 101, and aftercooler 104 cools the secondary compressed air discharged from secondary compressor 102.

[0032] As shown in the figure, the compressed air is drawn in from the compressed gas flow path 120, which is part of the air piping system. After being compressed once by the primary compressor 101, it is cooled by the intercooler 103. Then, the primary compressed air is drawn into the secondary compressor 102, where it is compressed a second time. The compressed air is then cooled by the aftercooler (heat exchanger) 104 before being discharged to the outside.

[0033] The oil pump 105 is a pressure delivery device that lubricates and cools the movable parts of the transmission device G, the primary compressor 101, and the secondary compressor 102, or delivers lubricating oil to the cooling jacket installed in the compressor housing. The oil pump 105 is configured in the lubricating oil flow path 121, which is part of the lubricating oil piping system, to circulate the lubricating oil within these devices. The movable parts of the compressor include bearings and timing gears of compression working components such as screw rotors.

[0034] The lubricating oil flow path 121 includes an oil cooler 106. After being drawn in by the oil pump 105, the lubricating oil is cooled by exchanging heat with the cooling medium in the oil cooler 106. The lubricating oil cooled by the oil cooler 106 is then supplied to the primary compressor 101 and the secondary compressor 102.

[0035] The cooling medium piping system branches from the main external water supply pipe 150 into three systems: an intercooler branch pipe 123 (intercooler piping system), an aftercooler branch pipe 124 (aftercooler piping system), and an oil cooler branch pipe 126. Intercooler branch pipe 123 connects to intercooler 103 and cools the primary compressed air discharged from primary compressor 101. Aftercooler branch pipe 124 connects to aftercooler 104 and cools the secondary compressed gas discharged from secondary compressor 102. Oil cooler branch pipe 126 connects to oil cooler 106 and cools the lubricating oil. The branch pipes converge downstream of each cooler and discharge outside the machine. In addition, the cooling water supplied from outside the machine to the main pipe 150, which is the cooling piping system, can be a structure that circulates with a water supply and drainage device connected to a pump unit or cooling tower, or it can be a unidirectional flow structure that supplies water from a source such as a river and discharges it into a sewer or the like via a purification device.

[0036] Here, the amount of cooling water allocated to each system of the aforementioned branch pipes is typically determined by the resistance of each piping path. Therefore, when a certain amount of cooling water is supplied from outside the unit, the amount of water flowing through the three systems after the branch is constant. Consequently, due to subsequent factors such as the deterioration of the water-cooled gas compressor 1 over the years and blockages in the branch pipe systems, there is concern about insufficient initial cooling performance. The reduction in cooling performance, such as changes in compressor discharge temperature and deterioration of cooler performance, is not limited to occurring smoothly within structural components; there is concern about uneven performance degradation. That is, if the deterioration of cooling performance occurs smoothly, increasing the flow rate supplied and discharged from the main pipe 150 can cope with the deterioration over the years. However, if the performance degradation occurs unevenly, even if cooling performance can be maintained for one structural component, overcooling may occur for another.

[0037] Therefore, one of the features of this embodiment is that the water-cooled gas compressor 1 includes a water flow regulating valve in each branch pipe system, monitors the cooling performance of each branch system according to the detection values ​​of various temperature detectors described later, and adjusts the water flow in each branch pipe system as needed.

[0038] In the water-cooled gas compressor 1, a water flow regulating valve 110 is installed on the intercooler branch pipe 123, a water flow regulating valve 112 is installed on the aftercooler branch pipe 124, and a water flow regulating valve 111 is installed on the oil cooler branch pipe 126. Each water flow regulating valve is, for example, an electrically operated automatic valve (valve body) capable of multi-stage water flow regulation. Each water flow regulating valve 110, 111, and 112 is communicatively connected to the control device 2, adjusting the valve body opening according to the instructions of the control device 2. Furthermore, this embodiment is described with each water flow regulating device being automatic, but a hybrid structure with partial manual operation is also possible.

[0039] Additionally, the water-cooled gas compressor 1 includes: a temperature detector 107 that detects the temperature of primary compressed air discharged from the primary compressor 101 to the secondary compressor 102 via the intercooler 103; a temperature detector 109 that detects the temperature of lubricating oil flowing from the gear chamber G to the primary compressor 101 and the secondary compressor 102 via the oil cooler 106 and finally returning to the gear chamber G; and a temperature detector 108 that detects the temperature of secondary compressed air discharged from the secondary compressor 102 via the aftercooler 104. Each temperature detector 107, 108, and 109 is communicatively connected to the control device 2, outputting the detected temperature to the control device 2 at arbitrary intervals. The control device 2 adjusts the opening of water flow regulating valves 110, 111, and 112 in accordance with the detected temperatures of each temperature detector, controlling the flow rate of cooling water flowing in the intercooler 103, oil cooler 106, and aftercooler 104.

[0040] Here, the opening of water flow regulating valves 110, 111, and 112 can be adjusted by changing the opening of only one water flow regulating valve, or by combining changes in the openings of multiple water flow regulating valves. For example, if the opening of water flow regulating valve 110 is increased, the flow rate of cooling water to the intercooler 103 increases, while the flow rate to the aftercooler 104 and oil cooler 106 relatively decreases. On the other hand, if the opening of water flow regulating valves 111 and 112 is decreased, the flow rate to the intercooler 103 relatively increases. In the following description, the opening of a specific water flow regulating valve is increased or decreased to increase the flow rate of cooling water to a specific cooler. However, the present invention is not limited to this. Without departing from the spirit of the invention, it also includes cases where the opening of other water flow regulating valves, different from the specific water flow regulating valve, is increased or decreased to control the flow rate to a specific cooler, and cases where the openings of each water flow regulating valve are combined.

[0041] exist Figure 2The control flow of the water-cooled gas compressor 1 in Embodiment 1 is shown. This control is performed by the control device 2. Furthermore, the various specified temperature thresholds described below are temperatures pre-set as specifications, taking into account the operating state of the water-cooled gas compressor 1 (speed of the drive unit M, output value of the variable speed control device 3, pressure detection device (not shown) in the air piping system, etc.). In this embodiment, the description is based on the case where each temperature threshold is set to a threshold that is a certain degree lower than the upper limit temperature for safe operation.

[0042] First, in S101, the control device 2 determines, based on the input from the temperature detector 107, whether the intake air temperature of the secondary compressor 102 (the temperature of the air discharged from the primary compressor 101 after passing through the intercooler 103) is above a predetermined temperature threshold. If the air temperature is above the predetermined threshold temperature, the process proceeds to S103 (S101: Yes). If the temperature is below the predetermined threshold, temperature monitoring continues (S101: No).

[0043] In S103, the control device 2 increases the opening of the water flow regulating valve 110, thereby increasing the water flow supplied to the intercooler 103.

[0044] In S105, the control device 2 determines whether the lubricating oil temperature detected by the temperature detector 109 installed in the oil cooler piping system is lower than a specified temperature threshold. If the lubricating oil temperature is lower than the specified temperature threshold, proceed to S107 (S105: Yes). If the lubricating oil temperature exceeds the specified temperature threshold, proceed to S111 (S105: No).

[0045] In S107, the control device 2 determines, based on the input from the temperature detector 108, whether the air temperature after passing through the aftercooler 104 (the air temperature discharged from the secondary compressor 102 after passing through the aftercooler 104) is lower than a predetermined temperature threshold. If the temperature detected by the temperature detector 108 is lower than the predetermined temperature threshold (S107: Yes), the control device 2 proceeds to S109. If the temperature detected by the temperature detector 108 exceeds the predetermined temperature threshold (S107: No), the control device 2 proceeds to S111.

[0046] In S109, control device 2 again determines, based on the temperature input from temperature detector 107, whether the air temperature drawn into secondary compressor 102 (air temperature after passing through intercooler 103) is lower than a specified temperature threshold. If the temperature is lower than the specified temperature threshold (S109: Yes), control device 2 proceeds to processing in S111. If the temperature exceeds the specified temperature threshold (S109: No), control device 2 returns to S103, further increasing the opening of water flow regulating valve 110.

[0047] In S111, the control device 2 reduces the opening of the water flow regulating valve 110. That is, in this step, the cooling performance of the aftercooler 104 and the oil cooler 106 is prevented from becoming insufficient beyond what is necessary due to the effect of the expanded water flow regulating valve 110 in S103.

[0048] Thus, according to this embodiment, the cooling performance of the intercooler 103, whose cooling performance has been reduced, can be compensated without impairing the cooling performance of the aftercooler 104 and the oil cooler 106. For example, if a protection function is provided to limit (stop or weaken) the operation of the water-cooled gas compressor 1 based on the abnormal temperature detected by each temperature detector, the operation restriction can be reduced, and a stable supply of compressed air can be provided accordingly.

[0049] Furthermore, this embodiment is not limited to the various contents described above. In particular, Figure 2 In the control, the opening of the water flow regulating valve 110 is changed only based on the temperature detected by the temperature regulator 107. However, it is also possible to change the opening of the water flow regulating valve 111 and / or 112 in the opposite direction based on the change of the opening of the water flow regulating valve 110 (for example, increase the opening of the water flow regulating valve 110 and correspondingly decrease the opening of the water flow regulating valve 111 and / or 112, etc.).

[0050] Furthermore, in this embodiment, an example is described in which the opening degree of the water flow regulating valve 110 is changed accordingly based on the temperature detected by the temperature detector 107. However, the opening degree of the water flow regulating valve 110 can also be adjusted based on the temperature detected by other temperature detectors 108 or 109.

[0051] Example 2

[0052] Next, Embodiment 2 of the present invention will be described. One feature of Embodiment 1 is that a temperature detector is used to monitor the reduction in cooling performance caused by changes in structural components (such as intercooler 103) over time, and the amount of water flowing through the distribution pipe system is adjusted to prevent the reduction in cooling performance of the structural components, thereby achieving a stable supply of compressed air from the water-cooled gas compressor 1.

[0053] In contrast, one feature of Embodiment 2 is that even when the balance of the cooling performance and characteristics of the equipment changes due to variations in the water-cooled gas compressor 1 over the years, power reduction is achieved even when this balance has been altered. More specifically, in this embodiment of a two-stage (multi-stage) compressor, the focus is on the feature of power reduction when the temperature of the intake air of the second-stage compressor 102, which performs the intake and discharge of higher-pressure air, is reduced.

[0054] The following uses Figure 1 and Figure 3The control method of Embodiment 2 will be described below. Furthermore, in the following description, elements that have the same function and structure as those in Embodiment 1 are sometimes referred to by the same reference numerals and detailed descriptions are omitted.

[0055] In S201, the control device 2 determines whether the temperature of the lubricating oil detected by the temperature detector 109 is lower than a predetermined threshold temperature. If it is lower than the predetermined threshold temperature (S201: Yes), the control device 2 proceeds to the processing in S203. If it exceeds the predetermined threshold temperature (S201: No), the lubricating oil temperature continues to be monitored.

[0056] In S203, the control device 2 determines whether the air temperature after passing through the aftercooler 104, detected by the temperature detector 108, is lower than a predetermined threshold temperature. If it is lower than the predetermined threshold temperature (S203: Yes), the control device 2 proceeds to the process in S205. If it is lower than the predetermined threshold temperature (S203: No), the control device 2 returns to the process in S201.

[0057] In S205, control device 2 increases the opening of water flow regulating valve 110, thereby increasing the amount of water flowing through intercooler 103. As a result, the temperature of the primary compressed gas discharged from primary compressor 101 becomes lower.

[0058] In S207, the control device 2 again determines whether the lubricating oil temperature detected by the temperature detector 109 is lower than the specified threshold temperature. If it is lower than the specified threshold temperature (S207: Yes), the control device 2 proceeds to the process in S209. If it exceeds the specified threshold temperature (S207: No), the control device 2 proceeds to the process in S211.

[0059] In S209, control device 2 determines whether the air temperature after passing through aftercooler 104, detected by temperature detector 108, is above a predetermined threshold temperature. If it is above the predetermined threshold temperature (S203: Yes), control device 2 proceeds to process S211. If it is below the predetermined threshold temperature (S203: No), control device 2 returns to process S205. That is, control device 2 performs process S205 again, thereby further increasing the opening of water flow regulating valve 110, further increasing the amount of cooling water flowing through intercooler 103, thereby lowering the temperature of primary compressed air and improving the power efficiency of secondary compressor 102.

[0060] In addition, in S211, the control device 2 reduces the opening of the water flow regulating valve 110, thereby increasing the amount of cooling water flowing through the oil cooler 106 and the aftercooler 104. This achieves equipment maintenance and reduces the temperature of the final discharged air.

[0061] Thus, according to Embodiment 2, the cooling performance of each part of the water-cooled gas compressor 1 and the final discharge air temperature can be kept below a certain level, thereby reducing the temperature of the primary compressed air and improving power efficiency. In particular, in Embodiment 2, after increasing the opening of the water flow regulating valve 110 in S205, the change in the threshold temperature of the lubricating oil temperature and the temperature of the compressed air discharged from the secondary compressor 102 is confirmed, and the cycle from S209 to S205 is repeated (S209: No). Therefore, it has the effect of gradually improving power based on actual measurement conditions while maintaining equipment maintenance, etc.

[0062] Example 3

[0063] Next, Embodiment 3 of the present invention will be described.

[0064] One feature of Embodiment 1 is that, in the event of a decrease in the cooling performance of a component of the water-cooled gas compressor 1 (e.g., the intercooler 103), this is prevented by changing the water flow rate in each branch manifold system. One feature of Embodiment 2 is that, in order to improve the power efficiency of the water-cooled gas compressor 1, the water flow rate in each branch manifold system is adjusted to maintain the equipment, preserve the temperature of the final ejected compressed air, and improve power efficiency.

[0065] In contrast, one feature of Example 3 is that by maintaining the lubricating oil temperature above a certain value, the viscosity is reduced, thereby improving the power efficiency of the water-cooled gas compressor 1, improving equipment maintenance, and maintaining the temperature of the final ejected compressed air. That is, the viscosity of the lubricating oil changes with temperature. If the viscosity is lower, the mechanical losses of the lubricating oil supply target and the flow resistance of the lubricating oil are reduced, correspondingly enabling a reduction in power consumption.

[0066] The following uses Figure 1 and Figure 4 The control method of Embodiment 2 will be described below. Furthermore, in the following description, elements that have the same function and structure as those in Embodiment 1 are sometimes referred to by the same reference numerals and detailed descriptions are omitted.

[0067] exist Figure 4 In step S301, the control device 2 determines whether the lubricating oil temperature detected by the temperature detector 109 is below a specified threshold. If the lubricating oil temperature is below the specified threshold (S301: Yes), the control device 2 proceeds to step S303. If the lubricating oil temperature is below the specified threshold (S301: No), the control device 2 continues to monitor the lubricating oil temperature.

[0068] In S303, control device 2 reduces the opening of water flow regulating valve 111, thereby reducing the flow rate of cooling water into oil cooler 106. As a result, the lubricating oil temperature reaches a certain high temperature, and its viscosity decreases.

[0069] In step S305, control device 2 determines whether the lubricating oil temperature detected by temperature detector 109 exceeds a specified threshold. If the lubricating oil temperature is below the specified threshold (S305: No), control device 2 returns to step S303, further increasing the opening of water flow regulating valve 111. That is, according to this process, as long as the lubricating oil temperature does not exceed the threshold (maintenance temperature), increasing the lubricating oil temperature reduces viscosity. If the lubricating oil temperature exceeds the specified threshold, control device 2 proceeds to step S307.

[0070] In S307, control device 2 reduces the opening of water flow regulating valve 111. Furthermore, this reduction in the water flow regulating valve's opening is a decrease of one (or more) level compared to the current opening. This reduction in opening level corresponds to the opening at which the lubricating oil temperature is below a threshold value; therefore, it is an opening that minimizes the rise in lubricating oil temperature and reduces the viscosity of the lubricating oil. As a result, the lubricating oil temperature is reduced below the threshold value (maintenance temperature), thereby enabling a reduction in power consumption and facilitating equipment maintenance.

[0071] The embodiments 1 to 3 for implementing the present invention have been described above, but the present invention is not limited to the above structures and processes, and various structures and processes can be used without departing from its spirit. For example, the structure and process of one embodiment can be replaced with the structure and process of other embodiments, and other structures can also be applied.

[0072] Explanation of reference numerals in the attached figures

[0073] 1: Water-cooled gas compressor

[0074] 2: Control device

[0075] 3: Variable speed control device

[0076] M: Drive unit

[0077] G: Transmission device

[0078] 101: First-stage compressor

[0079] 102: Two-stage compressor

[0080] 103: Intercooler

[0081] 104: Aftercooler

[0082] 105: Oil pump

[0083] 106: Oil Cooler

[0084] 107, 108, 109: Temperature detectors

[0085] 110, 111, 112: Water flow regulating valves

[0086] 120: Compressed gas flow path

[0087] 121: Lubricating oil flow path

[0088] 123: Intercooler branch pipe

[0089] 126: Oil cooler branch pipe

[0090] 124: Aftercooler branch pipe

[0091] 150: Main piping

[0092] 160: Check valve.

Claims

1. A gas compressor, comprising: A compressor used to compress gases; A liquid-cooled air cooler for cooling the compressed gas discharged from the compressor and a liquid-cooled oil cooler for cooling the lubricating oil that lubricates / cools the compressor; a cooling medium piping system for supplying cooling medium to the air cooler and the oil cooler; The gas compressor is characterized by having a control device and a feature: The cooling medium piping system has a main piping and branch piping for air coolers and oil coolers that branch off from the main piping to the air coolers and oil coolers. The gas compressor includes: A gas temperature detector downstream of the air cooler detects the temperature of the compressed gas discharged from the compressor; An oil temperature detector detects the temperature of the lubricating oil downstream of the oil cooler; and Multiple regulating valves, which respectively change the flow rate of the cooling medium through the air cooler branch pipe and the oil cooler branch pipe, When the gas temperature detector detects a value above a predetermined threshold, the control device changes the opening of at least one of the plurality of regulating valves, thereby increasing the flow rate of the cooling medium flowing in the air cooler's distribution pipe. After the control device changes the opening of at least one regulating valve, when the oil temperature detector detects a temperature above a specified threshold, it changes the opening of the at least one regulating valve to reduce the flow rate of the cooling medium flowing in the air cooler branch pipe.

2. A gas compressor, comprising: A compressor used to compress gases; A liquid-cooled air cooler for cooling the compressed gas discharged from the compressor and a liquid-cooled oil cooler for cooling the lubricating oil that lubricates / cools the compressor; a cooling medium piping system for supplying cooling medium to the air cooler and the oil cooler; The gas compressor is characterized by having a control device and a feature: The cooling medium piping system has a main piping and branch piping for air coolers and oil coolers that branch off from the main piping to the air coolers and oil coolers. The gas compressor includes: A gas temperature detector downstream of the air cooler detects the temperature of the compressed gas discharged from the compressor; An oil temperature detector detects the temperature of the lubricating oil downstream of the oil cooler; and Multiple regulating valves, which respectively change the flow rate of the cooling medium through the air cooler branch pipe and the oil cooler branch pipe, When the gas temperature detector detects a value above a predetermined threshold, the control device changes the opening of at least one of the plurality of regulating valves, thereby increasing the flow rate of the cooling medium flowing in the air cooler's distribution pipe. After the control device changes the opening of at least one regulating valve, when the detected temperature of the oil temperature detector is lower than a specified threshold, the opening of the at least one regulating valve is changed to further increase the flow rate of the cooling medium flowing in the air cooler branch pipe.

3. The gas compressor as described in claim 1 or 2, characterized in that: The compressor is a multi-stage compressor having at least two compressors, including a low-pressure stage compressor and a high-pressure stage compressor. The air cooler includes: an intercooler for cooling the compressed gas discharged from the low-pressure stage compressor; and an aftercooler for cooling the compressed gas discharged from the high-pressure stage compressor. The air cooler branch pipe includes an intermediate cooler branch pipe branching from the main pipe and an aftercooler branch pipe branching from the main pipe, and the intermediate cooler branch pipe and the aftercooler branch pipe are respectively provided with the regulating valve body. The gas temperature detector includes: a first temperature detector downstream of the intercooler that detects the temperature of the compressed gas discharged from the low-pressure stage compressor; and a second temperature detector downstream of the aftercooler that detects the temperature of the compressed gas discharged from the high-pressure stage compressor. When the detection value of the first temperature detector is above a specified threshold, the control device changes the opening of at least one regulating valve body to increase the flow rate of the cooling medium flowing in the branch pipe of the intercooler.

4. The gas compressor as described in claim 1 or 2, characterized in that: The compressor is an oil-free or liquid-supply type compressor that compresses air. The cooling medium is a coolant containing water.

5. A gas compressor comprising: a low-pressure stage compressor; High-pressure stage compressor; A liquid-cooled intercooler for cooling the compressed gas discharged from the low-pressure stage compressor; A liquid-cooled aftercooler for cooling the compressed gas discharged from the high-pressure stage compressor; a liquid-cooled oil cooler for cooling the lubricating oil that lubricates / cools the low-pressure stage compressor and the high-pressure stage compressor; and a cooling medium piping system for supplying cooling medium to the intercooler, aftercooler, and oil cooler. The gas compressor is characterized by having a control device and a feature: The cooling medium piping system has a main piping and branch pipes for the intercooler, aftercooler, and oil cooler, branching from the main piping to the intercooler, aftercooler, and oil cooler. The gas compressor includes: A first temperature detector detects the temperature of the compressed gas discharged from the low-pressure stage compressor downstream of the intercooler; A second temperature detector detects the temperature of the compressed gas discharged from the high-pressure stage compressor downstream of the aftercooler; An oil temperature detector detects the temperature of the lubricating oil downstream of the oil cooler; and Multiple regulating valves, which respectively change the flow rate of the cooling medium through the intercooler branch pipe, the aftercooler branch pipe, and the oil cooler branch pipe, When the oil temperature detector detects a value lower than a specified threshold, the control device changes the opening of at least one of the plurality of regulating valves to increase the flow rate of the cooling medium flowing in the intercooler branch pipe.

6. The gas compressor as described in claim 5, characterized in that: When the oil temperature detector detects a value lower than a specified threshold and the second temperature detector detects a temperature lower than a specified threshold, the control device changes the opening of at least one regulating valve body to increase the flow rate of the cooling medium flowing in the intercooler branch pipe.

7. The gas compressor as described in claim 5, characterized in that: After the control device changes the opening of at least one regulating valve body, when the detected temperature of the oil temperature detector is lower than a specified threshold, the opening of the at least one regulating valve body is changed to further increase the flow rate of the cooling medium flowing in the intercooler branch pipe.

8. The gas compressor as described in claim 5, characterized in that: After the control device changes the opening of at least one regulating valve, when the detected temperature of the oil temperature detector is lower than a specified threshold, it changes the opening of the at least one regulating valve to reduce the flow rate of the cooling medium flowing in the intercooler branch pipe.

9. The gas compressor as described in claim 5, characterized in that: After the control device changes the opening of at least one regulating valve, when the detected temperature of the oil temperature detector is lower than a specified threshold and the detected temperature of the second temperature detector is higher than the specified threshold, the opening of the at least one regulating valve is changed to reduce the flow rate of the cooling medium flowing in the intercooler branch pipe.

10. The gas compressor according to any one of claims 5 to 9, characterized in that: The compressor is an oil-free or liquid-supply type compressor that compresses air. The cooling medium is a coolant containing water.

11. A gas compressor comprising: a low-pressure stage compressor; High-pressure stage compressor; A liquid-cooled intercooler for cooling the compressed gas discharged from the low-pressure stage compressor; A liquid-cooled aftercooler for cooling the compressed gas discharged from the high-pressure stage compressor; a liquid-cooled oil cooler for cooling the lubricating oil that lubricates / cools the low-pressure stage compressor and the high-pressure stage compressor; and a cooling medium piping system for supplying cooling medium to the intercooler, aftercooler, and oil cooler. The gas compressor is characterized by having a control device and a feature: The cooling medium piping system has a main piping and branch pipes for the intercooler, aftercooler, and oil cooler, branching from the main piping to the intercooler, aftercooler, and oil cooler. The gas compressor includes: A first temperature detector detects the temperature of the compressed gas discharged from the low-pressure stage compressor downstream of the intercooler; A second temperature detector detects the temperature of the compressed gas discharged from the high-pressure stage compressor downstream of the aftercooler; An oil temperature detector detects the temperature of the lubricating oil downstream of the oil cooler; and Multiple regulating valves, which respectively change the flow rate of the cooling medium through the intercooler branch pipe, the aftercooler branch pipe, and the oil cooler branch pipe, When the oil temperature detector detects a value below a predetermined threshold, the control device changes the opening of at least one of the plurality of regulating valves, thereby reducing the flow rate of the cooling medium circulating in the oil cooler's branch pipes. After the control device reduces the flow rate of the cooling medium flowing in the oil cooler branch pipe by changing the opening of the at least one regulating valve body, when the detection value of the oil temperature detector exceeds a predetermined threshold, it further reduces the flow rate of the cooling medium flowing in the oil cooler branch pipe by changing the opening of the at least one regulating valve body.

12. The gas compressor as claimed in claim 11, characterized in that: The low-pressure stage compressor and the high-pressure stage compressor are oil-free or liquid-supply compressors that compress air. The cooling medium is a coolant containing water.

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