Gas compressor

Abstract

To prevent performance deterioration of a cooling system and deterioration of power efficiency of a gas compressor caused by aged deterioration and change of the gas compressor.SOLUTION: A gas compressor includes: a gas compressor body which compresses a gas; a liquid-cooled type air cooler which cools a compressed gas discharged from the gas compressor body and a liquid-cooled type oil cooler which cools a lubrication oil which lubricates / cools the gas compressor body; and a cooling medium pipe system which supplies a cooling medium to the air cooler and the oil cooler. The cooling medium pipe system is branched from a main pipeline toward the air cooler and the oil cooler and includes: temperature detectors which detect a compressed gas temperature at the downstream of the air cooler and a lubrication oil temperature at the downstream of the oil cooler; and adjustment valve bodies, each of which changes a circulation amount of the cooling medium, in the branched pipes. When a temperature of the compressed gas is higher or equal to a threshold value, a flow rate of the cooling medium circulating in the air cooler is increased by changing an opening of the adjustment valve body.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a gas compressor, and more particularly to a gas compressor that adjusts the amount of compressed gas and cooling liquid for equipment, etc. [Background technology]

[0002] Among compressors that compress gas (e.g., atmospheric air), liquid-cooled gas compressors are known that use a liquid (e.g., water or oil) as a cooling medium to cool the compressed gas and equipment. Patent Document 1 discloses a water-cooled compressor in which the cooling medium flows through a cooler (heat exchanger) for cooling the compressed gas to a predetermined temperature and for cooling components such as the gas compressor body, and performs cooling by exchanging heat with the compressed gas and equipment coolant. A cooling liquid system that absorbs the cooling liquid into the cooler consists of a main pipe and branch pipes, and each branch pipe is connected to each cooler. In compressors configured in this way, the liquid pressure in each branch system is generally adjusted in advance based on structural specifications such as the piping system and piping configuration so that a predetermined amount of liquid flows.

[0003] In addition, in gas compressors, excessive temperature rises in the compressed gas or lubricating oil can have a negative effect on the device, so some gas compressors are equipped with protective devices (e.g., temperature sensors and their control devices) to monitor the condition and have the function of forcibly stopping the gas compressor if an excessive temperature rise or the like is detected. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2020 / 012829 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the cooling performance of the cooler, compressor, and other components supplied with the coolant may differ from the initial design value depending on the usage and aging of the gas compressor. For example, if the temperature of the compressed air discharged from an aging gas compressor increases excessively, the heat exchange rate between the cooler and the gas compressor may also change, which may cause problems in terms of maintenance of the gas compressor.

[0006] Furthermore, if the flow passages inside the cooler become clogged due to dirt or deposits, the heat exchange rate with the cooling medium will similarly change, and there is a risk that sufficient cooling performance may not be maintained. Furthermore, deterioration over time may cause an imbalance in the cooling balance between the components that make up the gas compressor, which may result in a decrease in power efficiency.

[0007] There is a need for technology that can prevent the deterioration of cooling system performance and power efficiency that accompanies aging and changes in gas compressors. [Means for solving the problem]

[0008] In order to solve the above problem, the technology described in the claims is used. The present application discloses a number of technologies for solving the above problem, and one example thereof is a gas compressor including a gas compressor main body that compresses gas, a liquid-cooled air cooler that cools the compressed gas discharged from the gas compressor main body, a liquid-cooled oil cooler that cools the lubricating oil that lubricates / cools the gas compressor main body, a cooling medium piping system that supplies cooling medium to the air cooler and oil cooler, and a control device, wherein the cooling medium piping system includes a main piping, an air cooler branch piping that branches from the main piping toward the air cooler and the oil cooler, and an oil cooler branch piping that branches from the main piping toward the air cooler and the oil cooler. The air cooler branch piping includes a gas temperature detection device that detects the temperature of the compressed gas discharged by the gas compressor main body downstream of the air cooler, an oil temperature detector that detects the lubricating oil temperature downstream of the oil cooler, and an adjusting valve body that changes the flow rate of the cooling medium in each of the air cooler branch piping and the oil cooler branch piping, and when the detection value of the gas temperature detector is equal to or greater than a predetermined threshold, the control unit changes the opening of at least one adjusting valve body to increase the flow rate of the cooling medium flowing in the air cooler branch piping.

[0009] As another example, there is provided a gas compressor including at least two compressor bodies including a low-pressure stage and a high-pressure stage, a liquid-cooled intercooler that cools the compressed gas discharged from the low-pressure stage gas compressor body, a liquid-cooled aftercooler that cools the compressed gas discharged from the high-pressure stage gas compressor body, a liquid-cooled oil cooler that cools the lubricating oil that lubricates / cools the low-pressure stage and high-pressure stage gas compressor bodies, a cooling medium piping system that supplies cooling medium to the intercooler, aftercooler, and oil cooler, and a control device, wherein the cooling medium piping system includes a main pipe, an intercooler branch pipe that branches from the main pipe toward the intercooler, aftercooler, and oil cooler, and an oil cooler branch pipe that branches from the main pipe toward the intercooler, aftercooler, and oil cooler. The system has an intercooler branch pipe, and is equipped with a first temperature detector that detects the temperature of the compressed gas discharged by the low-pressure stage gas compressor downstream of the intercooler, a second temperature detection device that detects the temperature of the compressed gas discharged by the gas compressor main body downstream of the aftercooler, an oil temperature detector that detects the lubricating oil temperature downstream of the oil cooler, and adjustment valve bodies that change the flow rate of the cooling medium in each of the intercooler branch pipe, the aftercooler branch pipe, and the oil cooler branch pipe, and the control unit changes the opening of at least one adjustment valve body to increase the flow rate of the cooling medium circulating in the intercooler branch pipe when the detection value of the oil temperature detector is below a predetermined threshold.

[0010] As another example, there is provided a gas compressor including at least two compressor bodies including a low-pressure stage and a high-pressure stage, a liquid-cooled intercooler that cools the compressed gas discharged from the low-pressure stage gas compressor body, a liquid-cooled aftercooler that cools the compressed gas discharged from the high-pressure stage gas compressor body, a liquid-cooled oil cooler that cools the lubricating oil that lubricates / cools the low-pressure stage and high-pressure stage gas compressor bodies, a cooling medium piping system that supplies cooling medium to the intercooler, aftercooler, and oil cooler, and a control device, wherein the cooling medium piping system includes a main pipe, an intercooler branch pipe that branches from the main pipe toward the intercooler, aftercooler, and oil cooler, and an oil cooler branch pipe that branches from the main pipe toward the intercooler, aftercooler, and oil cooler. The system has an oil cooler branch pipe, and is equipped with a first temperature detector that detects the temperature of the compressed gas discharged by the low-pressure stage gas compressor downstream of the intercooler, a second temperature detection device that detects the temperature of the compressed gas discharged by the gas compressor main body downstream of the aftercooler, an oil temperature detector that detects the lubricating oil temperature downstream of the oil cooler, and adjustment valve bodies that change the flow rate of the cooling medium in each of the intercooler branch pipe, the aftercooler branch pipe, and the oil cooler branch pipe, and when the detection value of the oil temperature detector is below a predetermined threshold, the control unit changes the opening of at least one adjustment valve body to reduce the flow rate of the cooling medium circulating in the oil cooler branch pipe. [Effects of the Invention]

[0011] According to the present invention, it is possible to prevent the performance degradation of the cooling liquid system and the degradation of power efficiency that accompanies the use of a gas compressor.

[0012] Other objects, configurations and effects of the present invention will become apparent from the following description. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a configuration diagram schematically illustrating the configuration of a water-cooled gas compressor according to a first embodiment of the present invention and the flows of various fluids. [Figure 2] FIG. 2 is a flow chart showing the control flow of the water-cooled gas compressor according to the first embodiment. [Figure 3] FIG. 10 is a flow chart showing the control flow of the water-cooled gas compressor according to the second embodiment. [Figure 4] FIG. 10 is a flow chart showing the control flow of the water-cooled gas compressor according to the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the present invention will be described with reference to the drawings. [Example]

[0015] 1 shows the configuration and fluid flow of a water-cooled gas compressor 1 according to an embodiment. The water-cooled gas compressor 1 includes a control device 2, a variable speed control device 3, a drive device M, a power transmission device G, a first-stage compressor body 101, a two-stage compressor body 102, an intercooler 103, an aftercooler 104, and an oil cooler 106.

[0016] The control device 2 is electrically connected (not shown) to various components constituting the water-cooled gas compressor 1 and controls its operation. In this embodiment, the control device 2 will be described as realizing functional units through cooperation between a calculation unit and a program, and performing control thereby. Note that the present invention is not limited to this, and as another configuration example of the control device 2, part or all of it may be realized by an analog configuration. Furthermore, the control device 2 is not necessarily limited to being mounted on the water-cooled gas compressor 1, and can also be configured to be controlled from an external control device via a wired / wireless communication line. Also, it is possible to configure the control commands so that some are input / output by an external control device and some are input / output by the mounted control device.

[0017] The variable speed control device 3 is, for example, a power conversion device, and is a control device that varies the rotation speed by converting the power frequency in response to a command from the control device 2 and supplying it to the drive device M. In this example, an inverter is used.

[0018] The driving device M is a device that generates mechanical energy for driving the first-stage compressor body 101 and the two-stage compressor body 102 from the driving energy supplied from the variable speed control device 3. In this embodiment, an electric motor is used, but the present invention is not limited to this and may be a driving device that uses natural energy such as an internal combustion engine or wind or water power. When a driving device that uses an internal combustion engine or natural energy is used, the variable speed control device 3 will be a variable speed gear, a centrifugal pulley, or the like.

[0019] The power transmission device G is a mechanism that transmits driving energy from the drive device M to the first-stage compressor body 101 and the second-stage compressor body 102. In this embodiment, a gear device consisting of a combination of a push gear and a bull gear is applied as the power transmission device G. Other configuration examples of the power transmission device G include chain and belt drives. Note that in this embodiment, a configuration is described in which one drive device M drives two compressor bodies via the power transmission device G, but the present invention is not limited to this, and it is also possible to configure each compressor body with an independent drive device M of a direct-acting type. Furthermore, although this embodiment uses a so-called multi-stage machine as an example, the present invention can also be applied to a single-stage machine.

[0020] The one-stage compressor body 101 and the two-stage compressor body 102 are positive displacement compressors that generate compressed gas by operating using the drive energy of a drive unit M. In this embodiment, an oil-free screw compressor is used, but the present invention is not limited to this. It is also possible to use a liquid feed compressor that supplies liquid (oil or water) to a compression working chamber, or other positive displacement compressors such as scroll, reciprocating, vane, or claw compressors, or a centrifugal screw compressor such as a turbo compressor. In addition, the screw rotor housing of the one-stage compressor body 101 and the two-stage compressor body 102 is configured as a cooling jacket, and a coolant (e.g., water) flows inside to cool the compressor body.

[0021] The intercooler 103 and the aftercooler 104 are heat exchangers that exchange heat between a compressed gas (e.g., compressed air) and a cooling liquid (e.g., water). The intercooler 103 cools the primary compressed air discharged from the one-stage compressor body 101, and the aftercooler 104 cools the secondary compressed air discharged from the two-stage compressor body 102.

[0022] As shown in the figure, the air to be compressed is drawn in through a compressed gas flow path 120, is primarily compressed in a single-stage compressor body 101, and is then cooled in an intercooler 103. The primarily compressed air is then drawn into a two-stage compressor body 102, and the gas secondarily compressed in the two-stage compressor body 102 is cooled in an aftercooler (heat exchanger) 104 before being discharged outside the machine.

[0023] The oil pump 105 is a pressure-feeding device that lubricates and cools the moving parts of the power transmission device G, the first-stage compressor body 101, and the two-stage compressor body 102, and transports lubricating oil to a cooling jacket provided in the casing of the compressor body, and is arranged in a lubricating oil flow path 121 so that the lubricating oil circulates through these devices. The moving parts of the compressor body include bearings for compression operating members such as a screw rotor, timing gears, etc.

[0024] The lubricating oil flow path 121 includes an oil cooler 106. After being sucked by an oil pump 105, the lubricating oil is cooled by heat exchange with a cooling medium in the oil cooler 106. The lubricating oil cooled in the oil cooler 106 is supplied to the first-stage compressor body 101 and the two-stage compressor body 102.

[0025] The cooling medium piping system branches from a main piping 150, which carries water from the outside, into three piping systems: an intercooler branch piping 123, an aftercooler branch piping 124, and an oil cooler branch piping 126. The intercooler branch piping 123 is connected to the intercooler 103 and is a system that cools the primary compressed air discharged from the one-stage compressor body 101. The aftercooler branch piping 124 is connected to the aftercooler 104 and is a system that cools the secondary compressed air discharged from the two-stage compressor body 102. The oil cooler branch piping 126 is connected to the oil cooler 106 and is a system that cools lubricating oil. The branch piping joins downstream of each cooler and is discharged outside the machine. The cooling water supplied to the main pipe 150 from outside the machine may be configured to be circulated through a water supply and drainage system connected to, for example, a pump device or a cooling tower, or may be configured to have a biased flow, with the water supplied from a water source such as a river and discharged into a sewer or the like via a purification device or the like.

[0026] The amount of cooling water distributed to each branch piping system is typically determined based on the resistance of each piping path. Therefore, once a certain amount of cooling water is supplied from outside the compressor, the amount of water flowing to each of the three branch piping systems is also constant. Therefore, the initial cooling performance may be insufficient due to subsequent factors such as aging of the water-cooled gas compressor 1 or blockages in the branch piping systems. Degradation of cooling performance, such as changes in the compressor discharge temperature or deterioration of the cooler's performance, does not necessarily occur smoothly across components, resulting in an imbalance in performance degradation. In other words, if cooling performance degradation occurs smoothly, increasing the flow rate of water supplied and discharged from the main piping 150 can address aging degradation, but if performance degradation occurs unbalanced, problems such as maintaining cooling performance for one component while overcooling other components may occur.

[0027] Therefore, in this embodiment, one of the features of the water-cooled gas compressor 1 is that each branch piping system is provided with a water flow control valve, the cooling performance of each branch piping system is monitored based on the detected values ​​from various temperature detectors described later, and the amount of water circulating through each branch piping system is adjusted according to the requirements.

[0028] The water-cooled gas compressor 1 is provided with a water flow control valve 110 in an intercooler branch pipe 123, a water flow control valve 112 in an aftercooler branch pipe 124, and a water flow control valve 111 in an oil cooler branch pipe 126. Each water flow control valve is, for example, an electrically operated automatic valve (valve element), and is capable of adjusting the water flow in multiple stages. Each water flow control valve 110, 111, 112 is connected to a control device 2 so as to be able to communicate with the control device 2, and adjusts the opening of the valve element in response to commands from the control device 2. In this embodiment, the water volume adjusting devices are described as being automatic, but they may also be mixed with some being manual.

[0029] The water-cooled gas compressor 1 also includes a temperature detector 107 that detects the temperature of primary compressed air discharged from the first-stage compressor body 101 to the two-stage compressor body 102 via the intercooler 103, a temperature detector 109 that detects the temperature of lubricating oil that flows from the power transmission device G to the first-stage compressor body 101 and the two-stage compressor body 102 via the oil cooler 106 and is eventually returned to the power transmission device G, and a temperature detector 108 that detects the temperature of secondary compressed air discharged from the two-stage compressor body 102 via the aftercooler 104. Each of the temperature detectors 107, 108, and 109 is communicably connected to the control device 2 and outputs the detected temperatures to the control device 2 at arbitrary intervals. The control device 2 adjusts the openings of the water flow control valves 110, 111, and 112 in accordance with the temperatures detected by each of these temperature detectors, thereby controlling the flow rates of the cooling water flowing to the intercooler 103, the oil cooler 106, and the aftercooler 104.

[0030] Here, the opening of water flow control valves 110, 111, and 112 may be adjusted by changing the opening of only one water flow control valve, or by combining the openings of multiple water flow control valves. For example, increasing the opening of water flow control valve 110 increases the amount of coolant flowing into intercooler 103, but relatively reduces the flow rates to aftercooler 104 and oil cooler 106. On the other hand, decreasing the openings of water flow control valves 111 and 112 relatively increases the amount of coolant flowing into intercooler 103. In the following description, the opening of a specific water flow control valve is increased or decreased to increase the amount of coolant flowing to a specific cooler. However, the present invention is not limited to this and may include, without departing from the spirit of the invention, cases in which the opening of a water flow control valve other than the specific water flow control valve is increased or decreased to control the flow rate to the specific cooler, or a combination of the openings of the water flow control valve bodies.

[0031] 2 shows the flow of control of the water-cooled gas compressor 1 according to the first embodiment. This control is executed by the control device 2. Note that the various predetermined temperature thresholds in the following description are temperatures that are set in advance as specifications in consideration of the operating conditions of the water-cooled gas compressor 1 (such as the rotation speed of the drive device M, the output value of the variable speed control device 3, and a pressure detection device (not shown) in the air piping system). In this embodiment, each temperature threshold will be described as being set as a threshold that is lower by a certain amount than the upper limit temperature that allows safe operation. First, in S101, the control device 2 determines whether the intake air temperature of the two-stage compressor body 102 (the temperature of the air discharged from the first-stage compressor body 101 and passed through the intercooler 103) is equal to or higher than a predetermined temperature threshold, in response to an input from the temperature detector 107. If the air temperature is equal to or higher than the predetermined threshold temperature, the process proceeds to S103 (S101: YES), and if the air temperature is lower than the predetermined temperature threshold, the process continues to monitor the temperature (S101: NO).

[0032] In S103, the control device 2 increases the opening of the water flow regulation valve 110 to increase the amount of water supplied to the intercooler 103.

[0033] In S105, the control device 2 Lubricating oil flow path 121It is determined whether the lubricant temperature detected by the temperature detector 109 installed in the engine is below a predetermined temperature threshold. If the lubricant temperature is below the predetermined temperature threshold, the process proceeds to S107 (S105: YES). If the lubricant temperature exceeds the predetermined temperature threshold, the process proceeds to S111 (S105: NO ).

[0034] In S107, the control device 2 determines, in response to an input from the temperature detector 108, whether the temperature of the air after passing through the aftercooler 104 (the temperature of the air discharged from the two-stage compressor body 102 and passed through the aftercooler 104) is below a predetermined temperature threshold temperature. If the temperature detected by the temperature detector 108 is below 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.

[0035] In S109, the control device 2 determines whether the temperature of the air sucked into the two-stage compressor body 102 again (the temperature of the air after passing through the intercooler 103) is below the predetermined temperature threshold, based on the temperature input from the temperature detector 107. If the temperature is below the predetermined temperature threshold (S109: YES), the control device 2 proceeds to processing in S111. If the temperature exceeds the predetermined temperature threshold (S109: NO), the control device 2 returns to S103 and further increases the opening of the water flow control valve 110.

[0036] In S111, the control device 2 reduces the opening of the water flow control valve 110. That is, in this step, the cooling performance of the aftercooler 104 and the oil cooler 106 is prevented from becoming insufficient more than necessary due to the influence of the water flow control valve 110 that was increased in S103.

[0037] In this way, according to this embodiment, the cooling performance of the intercooler 103, which has been reduced, can be compensated for without impairing the cooling performance of the aftercooler 104 and the oil cooler 106. For example, when an abnormal temperature is detected by each temperature detector, the water-cooled gas compressor 1 Driving restrictions If the system is equipped with a protection function that performs operations such as stopping or degrading, the operational restrictions can be reduced, allowing for a stable supply of compressed air.

[0038] 2, an example is given in which only the opening degree of water flow rate adjustment valve 110 is changed in accordance with the temperature detected by temperature detector 107, but it is also possible to change the opening degree of water flow rate adjustment valves 111 and / or 112 to the opposite side in accordance with a change in the opening degree of water flow rate adjustment valve 110 (for example, increasing the opening degree of water flow rate adjustment valve 110 and decreasing the opening degree of water flow rate adjustment valves 111 and / or 112).

[0039] Furthermore, in this embodiment, an example has been described in which the opening degree of the water flow control valve 110 is changed in accordance with the temperature detected by the temperature detector 107, but it is also possible to adjust the opening degree of the water flow control valve 110 in accordance with the temperature detected by the other temperature detector 109 or 108. [Example]

[0040] Next, a description will be given of Example 2 of the present invention. One of the features of Example 1 is that a temperature detection device is used to monitor the deterioration of cooling performance of components (e.g., intercooler 103, etc.) due to aging or the like, and the amount of water flowing into the branch piping system is adjusted to prevent the deterioration of cooling performance of the components while ensuring a stable supply of compressed air from water-cooled gas compressor 1.

[0041] In contrast, one of the features of the second embodiment is that even if the balance of the cooling performance and characteristics of the equipment changes due to aging or the like of the water-cooled gas compressor 1, the power consumption is reduced under the circumstances where the balance has changed. More specifically, a two-stage (multi-stage) compressor such as that of the present embodiment has a feature that the power consumption is reduced when the temperature of the intake air of the two-stage compressor body 102, which takes in and discharges higher pressure air, is lowered.

[0042] Control in the second embodiment will be described below with reference to Figures 1 and 3. In the following description, elements that have the same functions and configurations as those in the first embodiment will be designated by the same reference numerals and detailed description thereof may be omitted.

[0043] In S201, the control device 2 determines whether the lubricant temperature is below a predetermined threshold temperature based on the input from the temperature detector 109. If the lubricant temperature is below the predetermined threshold temperature (S201: YES), the control device 2 proceeds to the process of S203. If the lubricant temperature exceeds the predetermined threshold temperature (S201: NO), the control device 2 continues to monitor the lubricant temperature.

[0044] In S203, the control device 2 determines whether the temperature of the air after passing through the aftercooler 104 is below a predetermined threshold temperature based on the input from the temperature detector 108. If the temperature is below the predetermined threshold temperature (S203: YES), the control device 2 proceeds to the process of S205. If the temperature is below the predetermined threshold temperature (S203: NO), the control device 2 returns to the process of S201.

[0045] In S205, the control device 2 increases the opening of the water flow control valve 110 to increase the amount of water circulating in the intercooler 103. This causes the temperature of the primary compressed gas discharged from the first-stage compressor body 101 to become lower.

[0046] In S207, the control device 2 again determines whether the lubricant temperature is below the predetermined threshold temperature based on the input from the temperature detector 109. If the lubricant temperature is below the predetermined threshold temperature (S207: YES), the control device 2 proceeds to the process of S209. If the lubricant temperature exceeds the predetermined threshold temperature (S207: NO), the control device 2 proceeds to the process of S211.

[0047] In S209, the control device 2 determines whether the temperature of the air after passing through the aftercooler 104 is equal to or higher than a predetermined threshold temperature based on the input from the temperature detector 108. If the temperature is equal to or higher than the predetermined threshold temperature ( S209 :YES), the control device 2 S211 If the temperature is below the predetermined threshold ( S209 :NO), the control device 2 S205 That is, by performing the process of S205 again, the control device 2 further widens the opening of the water flow control valve 110 and further increases the amount of cooling water flowing to the intercooler 103, thereby lowering the temperature of the primary compressed air and improving the power efficiency of the two-stage compressor body 102.

[0048] In S211, the control device 2 reduces the opening of the water flow control valve 110 to increase the amount of cooling water circulating in the oil cooler 106 and the aftercooler 104. That is, the device is maintained and the final discharge air temperature is reduced.

[0049] As described above, according to the second embodiment, it is possible to improve power efficiency by lowering the temperature of the primary compressed air while keeping the cooling performance of each part of the water-cooled gas compressor 1 and the final discharge air temperature at or below a certain level. In particular, in the second embodiment, after increasing the opening of the water flow control valve 110 in S205, the loop from S209 to S205 (S209: NO) is repeated while checking the change in the threshold temperature for the lubricating oil temperature and the compressed air temperature discharged from the two-stage compressor body 102, thereby achieving the effect of gradually improving power in accordance with the actual measurement situation while maintaining equipment maintenance, etc. [Example]

[0050] Next, a third embodiment of the present invention will be described. One of the features of the first embodiment is that when the cooling performance of some of the components (e.g., the intercooler 103) that cool the water-cooled gas compressor 1 decreases, this is prevented by changing the amount of water in each branch piping system. One of the features of the second embodiment is that in order to improve the power efficiency of the water-cooled gas compressor 1, the amount of water in each branch piping system is adjusted, thereby achieving maintenance of the equipment, maintaining the temperature of the final discharge compressed air, and improving the power efficiency.

[0051] In contrast, one of the features of Example 3 is that the viscosity is reduced by maintaining the lubricating oil temperature at a constant level or higher, thereby improving the power efficiency of the water-cooled gas compressor 1, facilitating equipment maintenance, and maintaining the temperature of the final discharge compressed air. That is, the viscosity of the lubricating oil changes depending on the temperature. A lower viscosity reduces mechanical loss at the destination of the lubricating oil and the flow resistance of the lubricating oil, thereby enabling a corresponding reduction in power consumption.

[0052] Below, using Figures 1 and 4, Example 3In the following description, elements having the same functions and configurations as those in the first embodiment will be designated by the same reference numerals and detailed description thereof will be omitted in some cases.

[0053] 4, the control device 2 determines whether the lubricant temperature is equal to or lower than a predetermined threshold based on the input from the temperature detector 109. If the lubricant temperature is equal to or lower than the predetermined threshold (S301: YES), the control device 2 proceeds to the processing of S303. If the lubricant temperature is higher than the predetermined threshold (S301: NO), the control device 2 continues to monitor the lubricant temperature.

[0054] In S303, the control device 2 reduces the opening of the water flow control valve 111 to reduce the flow rate of the cooling water flowing into the oil cooler 106. This causes the lubricating oil temperature to reach a constant high temperature, and the viscosity decreases.

[0055] In S305, the control device 2 determines whether the lubricant temperature exceeds a predetermined threshold based on the input from the temperature detector 109. If the lubricant temperature is equal to or lower than the predetermined threshold (S305: NO), the control device 2 returns to the process of S303 and further reduces the opening of the water flow control valve 111. In other words, this process increases the lubricant temperature and reduces the viscosity, unless the lubricant temperature exceeds the threshold (maintenance temperature). If the lubricant temperature exceeds the predetermined threshold, the control device 2 proceeds to the process of S307.

[0056] In S307, the control device 2 increases the opening of the water flow control valve 111. The water flow control valve is increased by one step (or more steps) from the current opening. The increased opening is the opening when the lubricating oil temperature is equal to or lower than the threshold value, so the increase in the lubricating oil temperature is suppressed as much as possible while the lubricating oil temperature is increased. Decrease in viscosity This allows the lubricating oil temperature to drop below the threshold (maintenance temperature), thereby reducing power consumption and enabling maintenance of equipment.

[0057] Although the first to third embodiments of the present invention have been described above, the present invention is not limited to the above-described configurations and processes, and various configurations and processes can be substituted without departing from the spirit of the present invention. For example, the configuration or process of one embodiment can be substituted with the configuration or process of another embodiment, or other configurations can be applied. [Explanation of symbols]

[0058] 1...water-cooled gas compressor, 2...controller, 3...variable speed control device, M...driver, G...power transmission device, 101...first-stage compressor body, 102...two-stage compressor body, 103...intercooler, 104...aftercooler, 105...oil pump, 106...oil cooler, 107, 108, 109...temperature detector, 110, 111, 112... Water flow control valve , 120... compressed gas flow path, 121... lubricating oil flow path, 123... intercooler branch pipe, 126... oil cooler branch pipe, 124... aftercooler branch pipe, 150... main pipe, 160... check valve

Claims

1. a gas compressor main body that compresses gas; a liquid-cooled air cooler that cools the compressed gas discharged from the gas compressor body; a liquid-cooled oil cooler that cools the lubricating oil that lubricates and cools the gas compressor body; The main pipe and an air cooler branch pipe branching from the main pipe toward the air cooler; an oil cooler branch pipe branching from the main pipe toward the oil cooler; a gas temperature detector that detects the temperature of compressed gas discharged from the gas compressor body downstream of the air cooler; an oil temperature detector that detects the temperature of the lubricating oil downstream of the oil cooler; a water flow control valve disposed in each of the air cooler branch pipe and the oil cooler branch pipe, for controlling the flow rate of the cooling medium; a control device that, when the detection value of the gas temperature detector is equal to or greater than a predetermined threshold, changes the aperture of at least one of the water flow control valves to increase the flow rate of the cooling medium circulating in the air cooler branch pipe, and, after changing the aperture of the at least one water flow control valve, changes the aperture of the at least one water flow control valve to reduce the flow rate of the cooling medium circulating in the air cooler branch pipe when the detection value of the oil temperature detector is equal to or greater than a predetermined threshold.

2. a gas compressor main body that compresses gas; a liquid-cooled air cooler that cools the compressed gas discharged from the gas compressor body; a liquid-cooled oil cooler that cools the lubricating oil that lubricates and cools the gas compressor body; The main pipe and an air cooler branch pipe branching from the main pipe toward the air cooler; an oil cooler branch pipe branching from the main pipe toward the oil cooler; a gas temperature detector that detects the temperature of compressed gas discharged from the gas compressor body downstream of the air cooler; an oil temperature detector that detects the temperature of the lubricating oil downstream of the oil cooler; a water flow control valve disposed in each of the air cooler branch pipe and the oil cooler branch pipe, for controlling the flow rate of the cooling medium; a control device that, when the detection value of the gas temperature detector is equal to or greater than a predetermined threshold, changes the aperture of at least one of the water flow control valves to increase the flow rate of the cooling medium circulating in the air cooler branch pipe, and, after changing the aperture of at least one of the water flow control valves, changes the aperture of at least one of the water flow control valves to further increase the flow rate of the cooling medium circulating in the air cooler branch pipe when the detection value of the oil temperature detector is less than the predetermined threshold and the detection value of the gas temperature detector is equal to or greater than the predetermined threshold.

3. 2. The gas compressor according to claim 1, The gas compressor body is composed of a one-stage compressor body and a two-stage compressor body, the air cooler is composed of an intercooler that cools the compressed gas discharged from the first-stage compressor body and an aftercooler that cools the compressed gas discharged from the second-stage compressor body, the air cooler branch pipe is composed of an intercooler branch pipe branching from the main pipe toward the intercooler, and an aftercooler branch pipe branching from the main pipe toward the aftercooler, the gas temperature detector comprises a first temperature detector that detects the temperature of the compressed gas discharged by the one-stage compressor body downstream of the intercooler, and a second temperature detector that detects the temperature of the compressed gas discharged by the two-stage compressor body downstream of the aftercooler, The control device, when the detection value of the first temperature detector is equal to or greater than a predetermined threshold, changes the opening degree of at least one of the water flow control valves to increase the flow rate of the cooling medium circulating in the intercooler branch pipe.

4. 3. The gas compressor according to claim 2, The gas compressor body is composed of a one-stage compressor body and a two-stage compressor body, the air cooler is composed of an intercooler that cools the compressed gas discharged from the first-stage compressor body and an aftercooler that cools the compressed gas discharged from the second-stage compressor body, the air cooler branch pipe is composed of an intercooler branch pipe branching from the main pipe toward the intercooler, and an aftercooler branch pipe branching from the main pipe toward the aftercooler, the gas temperature detector comprises a first temperature detector that detects the temperature of the compressed gas discharged by the one-stage compressor body downstream of the intercooler, and a second temperature detector that detects the temperature of the compressed gas discharged by the two-stage compressor body downstream of the aftercooler, The control device changes the opening degree of at least one of the water flow control valves when the detection value of the first temperature detector is equal to or greater than a predetermined threshold value, thereby increasing the flow rate of the cooling medium circulating in the intercooler branch pipe.

5. a one-stage compressor body that compresses gas; a liquid-cooled intercooler that cools the compressed gas discharged from the first-stage compressor body; a two-stage compressor body that compresses the compressed gas cooled by the intercooler; a liquid-cooled aftercooler that cools the compressed gas discharged from the two-stage compressor body; a liquid-cooled oil cooler that cools lubricating oil that lubricates and cools the first-stage compressor body and the second-stage compressor body; The main pipe and an intercooler branch pipe branching from the main pipe toward the intercooler; an aftercooler branch pipe branching from the main pipe toward the aftercooler; an oil cooler branch pipe branching from the main pipe toward the oil cooler; a first temperature detector configured to detect the temperature of compressed gas discharged from the first-stage compressor body downstream of the intercooler; a second temperature detector configured to detect the temperature of compressed gas discharged from the two-stage compressor body downstream of the aftercooler; an oil temperature detector that detects the temperature of the lubricating oil downstream of the oil cooler; a water flow control valve disposed in each of the intercooler branch pipe, the aftercooler branch pipe, and the oil cooler branch pipe, for controlling the flow rate of the cooling medium; a control device that, when the detection value of the oil temperature detector is below a predetermined threshold and the detection value of the second temperature detector is below a predetermined threshold, changes the opening degree of at least one of the water flow control valves to increase the flow rate of the cooling medium circulating in the intercooler branch pipe.

6. 6. The gas compressor according to claim 5, The control device a gas compressor that, after changing the opening degree of at least one of the water flow control valves, changes the opening degree of at least one of the water flow control valves when the detection value of the oil temperature detector is less than a predetermined threshold and the detection value of the second temperature detector is less than a predetermined threshold, thereby further increasing the flow rate of the cooling medium circulating in the intercooler branch pipe.

7. 6. The gas compressor according to claim 5, The control device a gas compressor that, after changing the opening degree of at least one of the water flow control valves, changes the opening degree of at least one of the water flow control valves, and reduces the flow rate of the cooling medium circulating in the intercooler branch pipe, if the detection value of the oil temperature detector is equal to or greater than a predetermined threshold value.

8. 6. The gas compressor according to claim 5, The control device a gas compressor that reduces the flow rate of the cooling medium circulating through the intercooler branch pipe when the detection value of the oil temperature detector is less than a predetermined threshold and the detection value of the second temperature detector is equal to or greater than a predetermined threshold after changing the opening degree of at least one of the water flow control valves.

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