Fluid machine

Abstract

This fluid machine comprises: a compressor body 1; a compressor body 2; an intake passage 12 that is connected to an intake port of the compressor body 1; air passages 14, 16, 18, 20 that allow communication between a discharge port of the compressor body 1 and an intake port of the compressor body 2; a three-way valve 32 that is provided to the air passages; an intake passage 13 that is connected to one port of the three-way valve 32; a low-pressure air tank 51 that is connected to an air passage 19 that branches from the air passages on the upstream side of the three-way valve 32; a high-pressure air tank 52 that allows communication between a discharge port of the compressor body 2 and air passages 21, 23, 25, 27; a first opening / closing valve that is provided to the air passage 19; a three-way valve 36 that is provided to the air passages 21, 23, 25, 27; an air passage 26 that connects at least one port of the three-way valve 36 and the air passage 19 on the downstream side of the first opening / closing valve; a three-way valve 36 that is provided to the air passages 21, 23, 25, 27; a controller 5 that is connected to a motor 3 for operating the compressor body 1; a controller 6 that is connected to a motor 4 for operating the compressor body 2; and a control unit 7 that controls the controller 5 and the controller 6.

Description

fluid machinery

[0001] The present disclosure relates to a fluid machine that compresses and delivers gas.

[0002] Compressors are used as fluid machinery that supplies compressed air to load equipment that uses the compressed air. Patent Document 1 (JP 2004-150393 A) describes a two-stage compressor in which a discharge port of a low-pressure stage compressor and a suction port of a high-pressure stage compressor are connected by a connecting passage via a selector valve. This document discloses that a check valve is provided upstream of the suction passage that branches at the connecting portion, and that by switching the selector valve, the compressor can function as a two-stage compressor or each compressor can function as an independent single-stage compressor.

[0003] Japanese Patent Application Laid-Open No. 2004-150393

[0004] Since one compressor can supply only one air pressure, if a user requires multiple different pressures, it may be necessary to install a compressor for each required pressure value. However, this increases the cost of installing the compressor and the installation area.

[0005] An object of the present disclosure is to enable selection of the pressure value or amount of compressed air in a fluid machine capable of two-stage compression using two compressors, thereby improving the performance of the fluid machine.

[0006] The fluid machine of the present disclosure includes a first compressor body, a second compressor body, a first intake air flow path connected to an intake port of the first compressor body, a first air flow path connecting a discharge port of the first compressor body and an intake port of the second compressor body, a first three-way valve provided on the first air flow path, a second intake air flow path connected to one port of the first three-way valve, a first air tank connected to a second air flow path branched from the first air flow path upstream of the first three-way valve, and a third air flow path connecting the discharge port of the second compressor body and an intake port of the second compressor body. the compressor includes a second air tank connected to the second air flow path, a first on-off valve provided on the second air flow path, a second three-way valve provided on the third air flow path, a fourth air flow path connecting one port of the second three-way valve to the second air flow path downstream of the first on-off valve, a first frequency converter connected to a first motor that operates the first compressor body, a second frequency converter connected to a second motor that operates the second compressor body, and a control unit that controls the first frequency converter and the second frequency converter. Here, the first three-way valve is capable of switching between communication between the first air flow path upstream of the first three-way valve and the first air flow path downstream of the first three-way valve, and communication between the first intake flow path and the first air flow path downstream of the first three-way valve, and the second three-way valve is capable of switching between communication between the third air flow path upstream of the second three-way valve and the third air flow path downstream of the second three-way valve, and communication between the fourth air flow path and the third air flow path downstream of the first three-way valve.

[0007] According to the present invention, in a fluid machine capable of two-stage compression using two compressors, it is possible to select the pressure value or amount of compressed air, thereby improving the performance of the fluid machine.

[0008] Fig. 1 is a block diagram showing the overall configuration of a fluid machine according to embodiment 1. Fig. 2 is a table showing the opening and closing of each valve in embodiment 1. Fig. 3 is a table showing the opening and closing of each valve in embodiment 1. Fig. 4 is a table showing the opening and closing of each valve in embodiment 1. Fig. 5 is a block diagram showing the overall configuration of a fluid machine according to embodiment 2. Fig. 6 is a table showing the opening and closing of each valve in embodiment 2. Fig. 7 is a table showing the opening and closing of each valve in embodiment 2.

[0009] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, identical parts are generally designated by the same reference numerals, and repeated explanations will be omitted. In the drawings, components may be depicted schematically in terms of width, thickness, shape, etc., compared to the actual embodiment in order to facilitate understanding of the invention. However, these are merely examples and do not limit the interpretation of the present disclosure.

[0010] 1 shows a block diagram of a fluid machine according to this embodiment. The fluid machine according to this embodiment is a machine that can be used as a two-stage compressor, in which air discharged from a compressor main body 1 (AE: Air End) on the low-pressure stage side is drawn into a suction port of a compressor main body 2 on the high-pressure stage side, and is further pressurized in the compressor main body 2 on the high-pressure stage side before being discharged. The compressor main body 2 is a device that can compress air to a pressure higher than that of the compressor main body 1.

[0011] A motor 3 that operates the compressor main body 1 is connected to the compressor main body (low-pressure stage compressor main body) 1, and a motor 4 that operates the compressor main body 2 is connected to the compressor main body 2. The motor 3 is connected to a controller (frequency converter, drive device, inverter) 5, and the motor 4 is connected to a controller (frequency converter, drive device, inverter) 6. The motors 3 and 4 are controlled independently by the controllers 5 and 6, respectively. A control unit (motor controller) 7 that centrally controls the controllers 5 and 6 is connected to each of the controllers 5 and 6. The control unit 7 is, for example, a control board.

[0012] An antenna 9 and an operation unit 8 are connected to the control unit 7. The antenna 9 receives signals from a network 10 and transmits them to the control unit 7. The operation unit 8 is composed of buttons or a touch panel for operating the control unit 7. Information regarding the operation of the fluid machinery can be transmitted and received between the network 10 and the antenna 9.

[0013] Each of the compressor bodies 1 and 2 has an intake port and a discharge port. A filter (suction filter) 11 is connected (communicates) to the intake port of the compressor body 1 via an intake flow path (air flow path) 12. That is, the intake flow path is connected to the intake port of the compressor body 1. The filter 11 serves to filter the intake air, and the intake flow path 12 introduces the air filtered by the filter 11 into the fluid machine. The compressor body 1 compresses the air sucked through the intake flow path 12. An intake flow path (air flow path) 13 branches off from the intake flow path 12. The upstream end of the intake flow path 13 is connected to the intake flow path 12, and the downstream end is connected to a three-way valve 32.

[0014] The fluid machine includes air flow paths (intermediate stage air flow paths) 14, 16, 18, and 20 that communicate from a discharge port of a compressor main body 1 to an intake port of a compressor main body (high-pressure stage compressor main body) 2 via an intercooler (IC) 15. The intercooler 15 is provided between the air flow path 14 and the air flow path 16. A drain separator 17 that separates moisture from compressed air is provided between the air flow path 16 and the air flow path 18. A downstream end of the air flow path 18 is connected to a three-way valve 32. That is, the three-way valve 32 is provided on the air flow path that communicates between the compressor main body 1 and the compressor main body 2.

[0015] The three-way valve 32 has three ports: NC (normally closed), COM (common), and NO (normally open). In the three-way valve 32, the port NC is connected to the intake air flow path 13, the port COM is connected to the air flow path 20, and the port NO is connected to the air flow path 18. The air flow path 20 is connected to the intake port of the compressor main body 2. The three-way valve 32 can switch between communication between the air flow path 18 upstream of the three-way valve 32 and the air flow path 20 downstream of the three-way valve 32, and communication between the intake air flow path 13 and the air flow path 20 downstream of the three-way valve 32. As shown in FIG. 1 , a flow rate adjustment valve 60 is provided on the air flow path 20.

[0016] The fluid machine includes air flow paths (discharge flow paths) 21, 23, 25, and 27 that connect the discharge port of the compressor main body 2 to the high-pressure air tank 52 via an aftercooler (AC) 22. The aftercooler 22 is provided between the air flow path 21 and the air flow path 23. A drain separator 24 that separates moisture from the compressed air is provided between the air flow path 23 and the air flow path 25. The downstream end of the air flow path 25 is connected to a three-way valve 36. That is, the three-way valve 36 is provided on the air flow path (discharge flow path) that connects the compressor main body 2 and the high-pressure air tank 52. The air flow path 27 is connected to the high-pressure air tank 52 downstream of the three-way valve 36.

[0017] The three-way valve 36 has three ports NC, COM, and NO. In the three-way valve 36, port NC is connected to the air flow path 26, port COM is connected to the air flow path 25, and port NO is connected to the air flow path 27. The downstream end of the air flow path 27 is connected to the high-pressure air tank 52. That is, one of the ports of the three-way valve 36 is connected to the high-pressure air tank 52, and the other is connected to the low-pressure air tank 51. The three-way valve 36 can switch between communication between the air flow path 25 and the air flow path 27 and communication between the air flow path 25 and the air flow path 26.

[0018] The air flow path 18 (the intermediate stage air flow path upstream of the three-way valve 32) branches midway and is connected to the air flow path 19. The downstream end of the air flow path 19 is connected to an on-off valve (two-way valve) 34. A check valve 33 is provided midway in the air flow path 19 to prevent air from flowing upstream (to the air flow path 18) from the on-off valve 34 side. The air flow path 19 upstream of the check valve 33 branches midway and is connected to the air flow path 28. The air flow path 28 branches into two on the downstream side, and on-off valves (air release valves) 30 and 38 are provided at the two branched downstream ends, respectively. It is also possible to consider that the on-off valve 34 is provided on the air flow path 19. The air flow path 26 connects (communicates) the air flow path 19 downstream of the on-off valve 34 and the air flow path 27 downstream of the three-way valve 36.

[0019] The on-off valve 34 has two ports NC and COM. In the on-off valve 34, port NC is connected to the air flow path 26, and port COM is connected to the air flow path 19. The air flow path 26 branches midway, and the downstream end of the branch is connected to the low-pressure air tank 51. It may also be considered that the on-off valve 34 is provided on the air flow path 19, and the air flow path 26 and the low-pressure air tank 51 are connected to the air flow path 19.

[0020] The air flow path 21 branches midway and is connected to an air flow path 29. A check valve 35 is provided midway in the air flow path 21 to prevent air from flowing from the post-cooler 22 side to the upstream side (the compressor body 2 side). The air flow path 21 upstream of the check valve 35 branches midway and is connected to the air flow path 29. The air flow path 29 branches into two on the downstream side, and an on-off valve (air release valve) 31 and an on-off valve (air release valve) 39 are provided at each of the two branched downstream ends.

[0021] A pressure sensor 41 is provided in the air flow path 14. A pressure sensor 42 and a flow rate sensor 43 are provided in the air flow path 18 downstream (on the three-way valve 32 side) of the branch point to which the air flow path 19 is connected. A flow rate sensor 45 is provided in the air flow path 21 upstream of the check valve 35 and upstream of the branch point to which the air flow path 29 is connected. A pressure sensor 44 is provided in the air flow path 26. A pressure sensor 46 is provided in the air flow path 27. The pressure sensors 44, 46 are used to detect the pressure in the low-pressure air tank 51 or the high-pressure air tank 52, respectively, for example, when the compressor bodies 1, 2 are stopped.

[0022] <Operation of Fluid Machine> The fluid machine of this embodiment can supply compressed air in four types of operation by opening, closing, and switching the on-off valve and the three-way valve. Here, the four types of operation are referred to as first operation, second operation, third operation, and fourth operation. The operation of the fluid machine in the first to fourth operations will be described below with reference to FIGS. 1 to 5. FIG. 2 is a table showing the opening and closing of each port in the load and unload operation of the three-way valve 32, the on-off valves 30, 38, 34, 31, and 39, and the three-way valve 36. The load operation is a loaded operation in which compressed air is generated, and the unload operation is a no-load operation in which compressed air is not generated.

[0023] Fig. 3 is a table showing the opening and closing of each port of the three-way valves 32 and 36 when they are energized and during a power outage. Fig. 4 is a table showing the opening and closing of each port of the on-off valves 30, 31, and 34 when they are energized and during a power outage. Fig. 5 is a table showing the opening and closing of each port of the on-off valves 38 and 39 when they are energized and during a power outage.

[0024] 2 to 5, open ports are shown in white and closed ports are shown in black. For example, as shown in Fig. 2, when the fluidic device is stopped, ports COM and NO of three-way valve 32 are open and port NC is closed. For three-way valves 32 and 36, the two open ports are in communication with each other.

[0025] <First Operation> In the first operation, single-stage compression is performed, and the compressor main body 1 is operated independently to perform single-stage compression. The control unit 7 operates the compressor main body 2 to supply compressed air to the low-pressure air tank 51 in a state in which the intake air flow path 13 and the air flow path 20 are connected in the three-way valve 32, the compressor main body 2 is stopped, the air flow path 25 and the air flow path 27 are connected in the three-way valve 36, and the on-off valve 34 is open. The specific operations of the first operation are as follows.

[0026] In the first operation, air is first filtered by the filter 11 and then taken into the compressor body 1 through the intake passage 12. As shown in Figure 2, in the first operation, port NO of the three-way valve 32 is closed, so air does not flow from the intake passage 13 to the air passage 18. In addition, because the compressor body 2 is stopped, air does not flow from the intake passage 13 into the compressor body 2.

[0027] Air is pressurized to a predetermined pressure in the compressor body 1. The compressed air discharged from the compressor body 1 passes through an air flow path 14 and is cooled in an intercooler 15. Drain water is generated in the compressed air due to cooling in the intercooler 15. The compressed air is sent from the intercooler 15 through the air flow path 15 to a drain separator 17, where it is separated from the drain water. The compressed air then passes through air flow paths 18 and 19 in this order, passes through an on-off valve 34, and is sent to a low-pressure air tank 51. Compressed air is supplied from the low-pressure air tank 51 to a terminal load facility (not shown) (for example, an air blower or a painting tool).

[0028] As described above, in the first operation, the fluid machine can supply compressed air at a relatively low pressure among the first to fourth operations by one-stage compression using the compressor main body 1.

[0029] In the event of a power outage, as shown in Figures 4 and 5, the on-off valve 30 closes, but the on-off valve 38 opens. This closes the air flow path, preventing compressed air from flowing back toward the compressor main body 1. This prevents the compressor main body 1 from rotating in the reverse direction and causing a breakdown. This also applies to the third and fourth operations.

[0030] <Second Operation> In the second operation, the compressor main body 2 is operated independently to perform single-stage compression. The control unit 7 operates the compressor main body 2 to supply compressed air to the high-pressure air tank 52 in a state in which the intake air flow path 13 and the air flow path 20 are connected in the three-way valve 32, the compressor main body 1 is stopped, and the air flow path 25 and the air flow path 27 are connected in the three-way valve 36. The specific operations of the second operation are as follows.

[0031] In the second operation, air is first filtered by the filter 11 and then passes through the intake passages 12 and 13 and the air passage 20 in this order before being drawn into the compressor body 2. As shown in Figure 2, in the second operation, port NO of the three-way valve 32 is closed, so air does not flow from the intake passage 13 to the air passage 18. In addition, because the compressor body 1 is stopped, air does not flow from the intake passage 12 into the compressor body 1.

[0032] Air is pressurized to a predetermined pressure in the compressor main body 2. The compressed air discharged from the compressor main body 2 passes through an air flow path 21 and is cooled in an after-cooler 22. Drain water is generated in the compressed air due to cooling in the after-cooler 22. The compressed air is sent from the after-cooler 22 through an air flow path 23 to a drain separator 24, where it is separated from the drain water. The compressed air then passes through an air flow path 25, passes through a three-way valve 36, and is sent to a high-pressure air tank 52. From the high-pressure air tank 52, compressed air is supplied to a terminal load facility (not shown).

[0033] As described above, in the first operation, the compressor main body 1 performs single-stage compression, which allows the supply of relatively low-pressure compressed air among the first to fourth operations. The compressor main body 2 can discharge a smaller amount of air than the compressor main body 1. While it is conceivable to obtain a small amount of discharged air from the compressor main body 1 by rotating the motor 3 at a constant speed, because the motor 3 has a minimum rotation speed, this would result in the supply of a larger amount of discharged air than desired, resulting in increased energy consumption. If a small amount of discharged air is sufficient, the user can easily obtain a small amount of compressed air by performing the second operation described above.

[0034] In the event of a power outage, as shown in Figures 4 and 5, the on-off valve 31 closes, but the on-off valve 39 opens. This closes the air flow path, preventing compressed air from flowing back into the compressor body 2. This prevents the compressor body 1 from rotating in the reverse direction and breaking down. This also applies to the third and fourth operations.

[0035] <Third Operation> In the third operation, both compressor bodies 1 and 2 are operated, and air that has undergone first-stage compression in each of compressor bodies 1 and 2 is supplied to one low-pressure air tank 51. The control unit 7 operates compressor bodies 1 and 2 to supply compressed air to low-pressure air tank 51 in a state in which intake air flow path 13 and air flow path 20 are connected in three-way valve 32, air flow path 25 and air flow path 26 are connected in three-way valve 36, and on-off valve 34 is open. Specific operations in the third operation are as follows.

[0036] In the third operation, air is first filtered by the filter 11 and then taken into the compressor body 1 through the intake air flow path 12. The air is also taken into the compressor body 2 through the intake air flow path 13 and the air flow path 20. As shown in Figure 2, in the third operation, the port NO of the three-way valve 32 is closed, so that air does not flow from the intake air flow paths 12 and 13 to the air flow path 18.

[0037] Air is pressurized to a predetermined pressure in the compressor body 1. The compressed air discharged from the compressor body 1 passes through an air flow path 14 and is cooled in an economizer 15. Drain water is generated in the compressed air due to the cooling in the economizer 15. The compressed air is sent from the economizer 15 through the air flow path 15 to a drain separator 17, where it is separated from the drain water. Thereafter, the compressed air passes through air flow paths 18 and 19 in this order, passes through an on-off valve 34, and is sent to a low-pressure air tank 51.

[0038] The compressor body 2 also pressurizes the air to a predetermined pressure. The compressed air discharged from the compressor body 2 passes through the air flow path 21 and is cooled in the after-cooler 22. Drain water is generated in the compressed air due to cooling in the after-cooler 22. The compressed air is sent from the after-cooler 22 through the air flow path 23 to the drain separator 24, where it is separated from the drain water. The compressed air then passes through the air flow path 25, passes through the three-way valve 36, and is sent to the low-pressure air tank 51 through the air flow path 26. In other words, compressed air discharged from both the compressor bodies 1 and 2 is supplied to the low-pressure air tank 51. As shown in FIG. 2 , because port NO of the three-way valve 36 is closed at this time, the compressed air sent from the compressor body 1 through the air flow path 26 and the compressed air sent from the compressor body 2 through the air flow path 25 do not flow into the air flow path 27. The low-pressure air tank 51 supplies compressed air to a terminal load facility (not shown).

[0039] As described above, in the third operation, the fluid machine can supply compressed air at a relatively low pressure among the first to fourth operations by using the single-stage compression using the compressor bodies 1 and 2. Here, the rotation speeds of the motors 3 and 4 are adjusted by the controllers 5 and 6. This aligns the pressures of the compressed air supplied from the compressor bodies 1 and 2, and prevents clogging of the air flow path 26 due to a pressure difference when the compressed air is joined together. In other words, the control unit 7 controls the pressure difference between the pressures of the compressed air supplied from the compressor bodies 1 and 2 to be as small as possible.

[0040] In the third operation, the provision of a flow rate control valve 60 makes it possible to adjust the ratio between the amount of air taken into the compressor body 1 side and the amount of air taken into the compressor body 2 side. This adjustment is performed by the control unit 7 by checking the pressure of the pressure sensor 44, for example.

[0041] In the third operation, since both the compressor bodies 1 and 2 are operating, the fluid machine can supply a larger amount of compressed air than in the first and second operations.

[0042] <Fourth Operation> In the fourth operation, both compressor bodies 1 and 2 are operated to perform two-stage compression. The control unit 7 operates the compressor bodies 1 and 2 to supply compressed air to the high-pressure air tank 52 in a state in which the air flow path 18 and the air flow path 20 are connected in the three-way valve 32, the air flow path 25 and the air flow path 27 are connected in the three-way valve 36, and the on-off valve 34 is closed. The specific operations of the fourth operation are as follows.

[0043] In the fourth operation, air is first filtered by the filter 11 and then taken into the compressor body 1 through the intake passage 12. As shown in Figure 2, in the fourth operation, the port NC of the three-way valve 32 is closed, so that air does not flow from the intake passage 13 into the air passages 18 and 20.

[0044] The air is pressurized to a predetermined pressure in the compressor body 1. As a result, the air is pressurized to, for example, 0.3 MPa (absolute pressure). The compressed air discharged from the compressor body 1 passes through the air flow path 14 and is cooled in the economizer 15. Drain water is generated in the compressed air due to cooling in the economizer 15. The compressed air is sent from the economizer 15 to the drain separator 17 through the air flow path 15, where it is separated from the drain water. The compressed air then passes through the air flow path 18 and the three-way valve 32, and is taken into the compressor body 2 through the air flow path 20. The air is pressurized to a predetermined pressure in the compressor body 2. As a result, the air is pressurized to, for example, 0.8 MPa (absolute pressure). Because the on-off valve 34 is closed, the compressed air sent to the air flow paths 14, 16, 18, 19, and 20 does not flow into the air flow path 26 side (low-pressure air tank 51 side), which is downstream of the on-off valve 34.

[0045] Compressed air discharged from the compressor main body 2 passes through the air flow path 21 and is cooled in the after-cooler 22. Drain water is generated in the compressed air due to cooling in the after-cooler 22. The compressed air is sent from the after-cooler 22 through the air flow path 23 to the drain separator 24, where it is separated from the drain water. The compressed air then passes through the air flow path 25 and the three-way valve 36, and is sent to the high-pressure air tank 52. As shown in FIG. 2 , because port NC of the three-way valve 36 is closed at this time, the compressed air sent from the compressor main body 2 through the air flow path 25 does not flow into the air flow path 26. Compressed air is supplied from the high-pressure air tank 52 to a terminal load facility (not shown).

[0046] As described above, in the fourth operation, the fluid machine can supply compressed air at a relatively high pressure among the first to fourth operations by two-stage compression using the compressor bodies 1 and 2.

[0047] <Effects of this embodiment> A user of a fluid machine may wish to have the fluid machine supply compressed air at multiple pressures. Furthermore, the user may be required to switch the operation of the fluid machine depending on whether the amount of compressed air required is small or large, thereby increasing or decreasing the amount of compressed air supplied. To realize such a fluid machine, it may be possible to install compressors according to the number of pressure values ​​or air volumes required for the compressed air. However, this increases the installation cost and installation area of ​​the fluid machine.

[0048] In contrast, in this embodiment, the intake air flow path 13 and the three-way valve 32 are provided, allowing the compressor body 2 to draw air directly from the filter 11 without passing through the compressor body 1. Furthermore, air flow paths 19 and 26 are provided branching from the air flow path 18, which is an intermediate-stage air flow path between the compressor bodies 1 and 2, and the air flow paths 19 and 26 are connected to the low-pressure air tank 51. This allows the fluid machine capable of two-stage compression to perform not only the fourth operation described above, but also the first, second, and third operations. Therefore, by using the fluid machine of this embodiment, users can obtain compressed air at a desired pressure and in a desired amount. In other words, when using two compressor bodies required for two-stage compression, the range of compressed air pressures and compressed air amounts obtained by using the fluid machine can be increased without adding additional compressor bodies, while suppressing an increase in the size of the fluid machine. This improves the performance of the fluid machine.

[0049] Here, in order to realize the above-described fluid machine, it is not necessary to introduce as many compressor bodies as the number of pressure values ​​or air volumes required, which prevents an increase in the introduction cost and installation area of ​​the fluid machine.

[0050] Furthermore, since the only filter provided for the two compressor bodies 1 and 2 is the filter 11, an increase in the size and introduction cost of the fluid machinery can be prevented.

[0051] Second Embodiment Fig. 6 shows a block diagram of a fluid machine according to a second embodiment. In this embodiment, the intake passage 12 provided on the intake side of the compressor body 1 is not connected to the three-way valve 32, but the port NC of the three-way valve 32 is connected to the filter 11B via the intake passage (air passage) 13A. In other words, the upstream end of the intake passage 13A is connected to the filter 11B. This embodiment differs from the first embodiment in that two filters 11A and 11B are provided, and the filter 11A is connected to the intake port of the compressor body 1 via the intake passage 12, and the filter 11B is connected to the intake port of the compressor body 2 via the air passage 20, the three-way valve 32, and the intake passage 13A.

[0052] This embodiment also differs from the first embodiment in that an on-off valve (discharge valve) 37 is provided in the air flow path 27 between the three-way valve 36 and the high-pressure air tank 52. A pressure sensor 46 is provided in the air flow path 27 between the on-off valve 37 and the high-pressure air tank 52.

[0053] 7 is a table showing the opening and closing of each port during the load / unload operation of the three-way valve 32, the on-off valves 30, 38, 34, 31, 39, the three-way valve 36, and the on-off valve 37. The operations of the on-off valves 30, 38, 34, 31, 39, and the three-way valve 36 are the same as those shown in FIG.

[0054] Fig. 8 is a table showing the opening and closing of each port of the on-off valves 30, 31, 34, and 37 when they are energized and when there is a power outage. The opening and closing operations of each port of the on-off valves 32 and 36 when they are energized and when there is a power outage are the same as those shown in Fig. 3. The opening and closing operations of each port of the on-off valves 38 and 39 when they are energized and when there is a power outage are the same as those shown in Fig. 5.

[0055] In this embodiment, the first to fourth operations of the first embodiment can also be performed.

[0056] The operation of the first operation is the same as that of the first embodiment, except that air is first drawn in through the filter 11A.

[0057] The operation of the second operation is the same as that of embodiment 1, except that air is first sucked in through filter 11B, passes through intake flow path 13A, and is then sucked into the compressor main body 2 through three-way valve 32 and air flow path 20.

[0058] The operation of the third operation is the same as that of embodiment 1, except that air is drawn into the compressor main body 1 through filter 11A, and the air drawn in through filter 11B and passed through the intake flow path 13A is drawn into the compressor main body 2 through the three-way valve 32 and the air flow path 20.

[0059] The operation of the fourth operation is the same as that of the first embodiment except that air is first drawn in through the filter 11A.

[0060] <Effects of the embodiment> In this embodiment, as described in the first embodiment, compressed air can be obtained at a pressure selected by the user from a plurality of pressures, and the user can simultaneously obtain compressed air at a plurality of pressures. Furthermore, by using the fluid machine of this embodiment, the user can obtain the amount of compressed air desired by the user. Therefore, the performance of the fluid machine can be improved.

[0061] Furthermore, in this embodiment, filters 11A and 11B are provided for the two compressor bodies 1 and 2, respectively. Therefore, when performing the third operation, which involves a large amount of air suction, the pressure loss (suction pressure loss) in the filter can be reduced compared to when only one filter is provided. This makes it possible to suppress a decrease in compressor performance.

[0062] Furthermore, if there is no on-off valve (discharge valve) 37, when the ports NO and COM of the three-way valve 36 are connected to the pressure of the high-pressure air tank 52, the pressure of the high-pressure air tank 52 is constantly applied to the check valve 35. If the temperature around the fluid machine drops at this time, drain water will be generated in the flow path pressurized by the high-pressure air tank 52, and the check valve 35, for example, will be prone to rust.

[0063] In this embodiment, on-off valves (discharge valves) 34, 37 are provided, and by closing the on-off valves 34, 37 when the compressor bodies 1, 2 are stopped, the pressure of the low-pressure air tank 51 or the high-pressure air tank 52 is prevented from being applied to the check valves 33, 35. This prevents the generation of drain water and the associated rust.

[0064] Although the embodiment and representative modifications have been described above, the above-described technology can be applied to various modifications other than the modifications exemplified. For example, the on-off valve 37 described in the second embodiment may be provided in the fluid machine of the first embodiment.

[0065] The present invention can be widely used in fluid machinery.

[0066] 1, 2 Compressor body 3, 4 Motor 5, 6 Controller 7 Control unit 11, 11A, 11B Filter 12, 13, 13A Intake air flow path 14, 16, 18, 19, 20, 21, 23, 25, 26, 27 Air flow path 15 Intercooler 17, 24 Drain separator 22 Post-cooler 30, 31, 34, 37, 38, 39 Opening / closing valve 32, 36 Three-way valve 33, 35 Check valve 41, 42, 44, 45, 46 Pressure sensor 43, 45 Flow rate sensor 51 Low pressure air tank 52 High pressure air tank 60 Flow rate adjustment valve COM, NC, NO port

Claims

a first compressor body; a second compressor body; a first intake air flow path connected to an intake port of the first compressor body; a first air flow path connecting a discharge port of the first compressor body and an intake port of the second compressor body; a first three-way valve provided on the first air flow path; a second intake air flow path connected to one port of the first three-way valve; a first air tank connected to a second air flow path branched from the first air flow path upstream of the first three-way valve; a second air tank connected to the discharge port of the second compressor body through a third air flow path; a first on-off valve provided on the second air flow path; a second three-way valve provided on the third air flow path; a fourth air flow path connecting one port of the second three-way valve and the second air flow path downstream of the first on-off valve; and a first frequency converter connected to a first motor that operates the first compressor body. a second frequency converter connected to a second motor that operates the second compressor body; and a control unit that controls the first frequency converter and the second frequency converter, wherein the first three-way valve is capable of switching between communication between the first air flow path upstream of the first three-way valve and the first air flow path downstream of the first three-way valve, and communication between the second intake air flow path and the first air flow path downstream of the first three-way valve, and the second three-way valve is capable of switching between communication between the third air flow path upstream of the second three-way valve and the third air flow path downstream of the second three-way valve, and communication between the third air flow path upstream of the second three-way valve and the fourth air flow path.

2. A fluid machine as described in claim 1, wherein the control unit operates the first compressor main body to supply compressed air to the first air tank when the second intake flow path and the first air flow path downstream of the first three-way valve are connected in the first three-way valve, the second compressor main body is stopped, the second three-way valve is connected in the third air flow path upstream of the second three-way valve and the third air flow path downstream of the second three-way valve, and the first on-off valve is open.

3. A fluid machine according to claim 1, wherein the control unit operates the second compressor main body to supply compressed air to the second air tank in a state in which, in the first three-way valve, the second intake flow path and the first air flow path downstream of the first three-way valve are connected, the first compressor main body is stopped, and, in the second three-way valve, the third air flow path upstream of the second three-way valve and the third air flow path downstream of the second three-way valve are connected.

4. A fluid machine as described in claim 1, wherein the control unit operates the first compressor main body and the second compressor main body to supply compressed air to the first air tank when the second intake flow path and the first air flow path downstream of the first three-way valve are connected in the first three-way valve, the third air flow path and the fourth air flow path upstream of the second three-way valve are connected in the second three-way valve, and the first opening / closing valve is open.

5. A fluid machine as described in claim 4, further comprising a flow control valve provided on the first air flow path downstream of the first three-way valve, the flow control valve adjusting the ratio between the amount of air taken into the first compressor body and the amount of air taken into the second compressor body.

6. A fluid machine according to claim 1, wherein the control unit operates the first compressor main body and the second compressor main body to supply compressed air to the second air tank when, in the first three-way valve, the first air flow path upstream of the first three-way valve and the first air flow path downstream of the first three-way valve are connected, and in the second three-way valve, the third air flow path upstream of the second three-way valve and the third air flow path downstream of the second three-way valve are connected, and the first on-off valve is closed.

7. A fluid machine as described in claim 1, further comprising a filter for filtering intake air, the filter and the intake port of the first compressor body being connected by the first intake flow path, and the upstream end of the second intake flow path being connected to the first intake flow path.

8. A fluid machine as described in claim 1, further comprising a first filter and a second filter for filtering intake air, the first filter and the intake port of the first compressor body being connected by the first intake flow path, and the upstream end of the second intake flow path being connected to the second filter.

9. A fluid machine according to claim 1, further comprising a second on-off valve provided on the third air flow path downstream of the second three-way valve.

Images