Fluid machinery

Abstract

To provide a fluid machine that can prevent deterioration caused by the inclusion of moisture in the lubricating oil. [Solution] The system comprises a fluid machine body 1 that discharges fluid, lubricating oil LO flowing through the fluid machine body 1, a viscosity sensor 2 that detects the viscosity V of the lubricating oil LO, an oil temperature sensor 3 that detects the temperature T of the lubricating oil LO, a cooling device 4 that cools the lubricating oil LO, and a control device 5 that controls the operation of the cooling device 4 based on the viscosity threshold Vth of the lubricating oil LO at the temperature T of the lubricating oil LO detected by the oil temperature sensor 3 and the viscosity V detected by the viscosity sensor 2.

Description

Technical Field

[0001] The present invention relates to a fluid machine.

Background Art

[0002] Fluid machines that use lubricating oil for lubricating moving parts and cooling heat-generating parts are widely used. If the deterioration of the lubricating oil is left unattended, not only does the performance of the fluid machine decline, but it also leads to failures and an increase in maintenance costs. To solve this problem, for example, Patent Document 1 discloses a control device that determines whether the refrigerating machine oil (lubricating oil) in a refrigerant circuit is deteriorated based on the detection result of an optical detection sensor, and a notification unit that notifies whether the refrigerating machine oil in the refrigerant circuit is deteriorated.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the fluid machine (refrigeration cycle device) of Patent Document 1, the control device determines whether the lubricating oil (refrigerating machine oil) is deteriorated based on the detection result of the optical detection sensor. However, in the fluid machine of Patent Document 1, even if the deterioration of the lubricating oil can be determined, it is difficult to prevent the deterioration of the lubricating oil itself.

[0005] An object of the present invention is to provide a fluid machine capable of preventing deterioration of lubricating oil.

Means for Solving the Problems

[0006] The present invention includes several means for solving the above problems, but one example is a fluid machine body that discharges fluid, a lubricating oil that flows through the fluid machine body, a viscosity sensor that detects the viscosity of the lubricating oil, an oil temperature sensor that detects the temperature of the lubricating oil, a cooling device that cools the lubricating oil, and a control device that controls the operation of the cooling device based on a threshold value of the viscosity of the lubricating oil at the temperature of the lubricating oil detected by the oil temperature sensor and the viscosity detected by the viscosity sensor. [Effects of the Invention]

[0007] According to the present invention, the operation of the cooling device can be controlled according to the amount of water contained in the lubricating oil, which can be determined from the viscosity of the lubricating oil, thereby reducing the amount of water contained in the lubricating oil and preventing deterioration of the lubricating oil caused by the water contained in the lubricating oil. Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram showing the general configuration of a fluid machine according to an embodiment of the present invention. [Figure 2] This graph shows the relationship between the water content in the lubricating oil circulating through the body of a fluid machine according to an embodiment of the present invention and the viscosity of the lubricating oil. [Figure 3] This figure shows an example of a control flowchart performed by a control device for a fluid machine according to an embodiment of the present invention. [Modes for carrying out the invention]

[0009] The configuration and operation of a fluid machine according to an embodiment of the present invention will be described below with reference to the drawings. In each figure, the same reference numerals indicate the same part.

[0010] Figure 1 is a schematic diagram showing the general configuration of a fluid machine according to an embodiment of the present invention. Figure 2 is a graph showing the relationship between the water content in the lubricating oil circulating through the fluid machine body of the fluid machine according to an embodiment of the present invention and the viscosity of the lubricating oil.

[0011] The fluid machine is an oil-lubricated air compressor (hereinafter referred to as compressor 100), and comprises a fluid machine body (compressor body 1) that discharges fluid, lubricating oil LO that flows through the fluid machine body, a viscosity sensor 2 that detects the viscosity of the lubricating oil LO, an oil temperature sensor 3 that detects the temperature of the lubricating oil LO, a cooling device 4 that cools the lubricating oil LO, and a control device 5 that controls the operation of the cooling device 4 based on the threshold value of the lubricating oil LO at the temperature T of the lubricating oil LO detected by the oil temperature sensor 3 (upper viscosity Vmax, see Figure 2) and the viscosity V detected by the viscosity sensor 2.

[0012] The compressor body 1 is driven by an electric motor 1a and has a pair of male and female screw rotors that mesh with each other. It is a device that compresses the air drawn in from the suction filter 1b and through the throttle valve 1c.

[0013] A compression chamber is formed by the tooth grooves of a pair of screw rotors. Lubricating oil LO is injected into this compression chamber. The lubricating oil LO lubricates the meshing of the pair of screw rotors, cools the compression heat, and seals the compression chamber.

[0014] When the male rotor of the pair of screw rotors is rotated by the electric motor 1a, the air in the compression chamber is compressed together with the lubricating oil LO by the pair of screw rotors, and the compressed air PA containing the lubricating oil LO is discharged from the discharge pipe 1d to the gas-liquid separator 1e.

[0015] The gas-liquid separator 1e is a device that separates lubricating oil LO from compressed air PA, which is a gas-liquid mixture containing lubricating oil LO discharged from the compressor body 1. The gas-liquid separator 1e can be of the impact type, centrifugal type, or a combination of both.

[0016] The lubricating oil LO separated by the gas-liquid separator 1e accumulates at the bottom of the gas-liquid separator 1e and flows through the lubricating oil passage 6 before being returned to the compressor body 1.

[0017] The lubricating oil flow path 6 is a flow path for returning the lubricating oil LO separated by the gas-liquid separator 1e from the gas-liquid separator 1e to the compressor main body 1. A temperature control valve 6a is provided downstream of the gas-liquid separator 1e.

[0018] The temperature control valve 6a is a three-way valve, and switches to connect the upstream main flow path 6b communicating with the gas-liquid separator 1e to either an oil cooling flow path 6c communicating with the compressor main body 1 via the cooling device 4 or a bypass flow path 6d communicating with the compressor main body 1 without passing through the cooling device 4. When the lubricating oil LO exceeds a predetermined temperature by the temperature control valve 6a, the main flow path 6b is connected to the oil cooling flow path 6c, and when the lubricating oil LO is below the predetermined temperature, the main flow path 6b is connected to the bypass flow path 6d.

[0019] The cooling device 4 is a device for cooling the lubricating oil LO sent to the oil cooling flow path 6c and the compressed air PA discharged from the compressor main body 1, and preferably has a cooling fan 4c that supplies a cooling fluid (air) to the heat exchanger. The heat exchanger preferably has an oil cooler 4a through which the lubricating oil LO flows and an aftercooler 4b through which the compressed air PA flows.

[0020] The oil cooler 4a is an air-cooled heat exchanger, and forcibly cools the lubricating oil LO by exchanging heat between the air flow 4d generated by the cooling fan 4c and the lubricating oil LO flowing through the oil cooler 4a. Note that a water-cooled oil cooler may also be used.

[0021] The oil cooling flow path 6c includes an oil cooler 4a between the temperature control valve 6a and a confluence portion 6e where the oil cooling flow path 6c and the bypass flow path 6d merge. The bypass flow path 6d communicates the temperature control valve 6a and the confluence portion 6e, and returns the lubricating oil LO to the compressor main body 1 without passing through the cooling device 4.

[0022] An oil filter 6g is preferably provided in the downstream main flow path 6f between the confluence portion 6e and the compressor main body 1, and it is preferable to remove impurities from the lubricating oil LO returned to the compressor main body 1 by the oil filter 6g.

[0023] The viscosity sensor 2 is a sensor that detects the viscosity of the lubricating oil LO. The viscosity sensor 2 is a plurality of viscosity sensors 2a to 2e, and it is preferable that each of the plurality of viscosity sensors 2a to 2e is provided at a different position in the lubricating oil flow path 6. For example, the first viscosity sensor 2a is provided in a flow path (upstream main flow path 6b) that communicates the gas-liquid separator 1e and the temperature adjustment valve 6a. The second viscosity sensor 2b is provided in a flow path (a flow path upstream of the oil cooling flow path 6c) that communicates the temperature adjustment valve 6a and the oil cooler 4a. The third viscosity sensor 2c is provided in a flow path (a flow path downstream of the oil cooling flow path 6c) that communicates the oil cooler 4a and the confluence portion 6e. The fourth viscosity sensor 2d is provided in a flow path (an upstream position adjacent to the oil filter 6g in the downstream main flow path 6f) that communicates the confluence portion 6e and the oil filter 6g. The fifth viscosity sensor 2e is provided in a flow path (an upstream position adjacent to the compressor body 1 in the downstream main flow path 6f) that communicates the oil filter 6g and the compressor body 1.

[0024] Also, the viscosity sensor 2 is preferably provided at a position between the cooling device 4 (oil cooler 4a) and the fluid machine body (compressor body 1) in the lubricating oil flow path 6, and for example, it is preferably provided at the positions of the illustrated viscosity sensors 2c to 2e.

[0025] The oil temperature sensor 3 is a sensor that detects the temperature of the lubricating oil LO. In this embodiment, a plurality of oil temperature sensors 3a to 3e are provided as the oil temperature sensor 3, and it is preferable that each of the plurality of oil temperature sensors 3a to 3e is provided at a different position in the lubricating oil flow path 6 as shown in the figure. For example, the first oil temperature sensor 3a is provided in the flow path (upstream main flow path 6b) that connects the gas-liquid separator 1e and the temperature control valve 6a. The second oil temperature sensor 3b is provided in the flow path (upstream flow path of the oil cooling flow path 6c) that connects the temperature control valve 6a and the oil cooler 4a. The third oil temperature sensor 3c is provided in the flow path (upstream flow path of the oil cooling flow path 6c) that connects the oil cooler 4a and the confluence section 6e. The fourth oil temperature sensor 3d is provided in the flow path (upstream position adjacent to the oil filter 6g in the downstream main flow path 6f) that connects the confluence section 6e and the oil filter 6g. A fifth oil temperature sensor 3e is provided in the flow path connecting the oil filter 6g and the compressor body 1 (at an upstream position adjacent to the compressor body 1 in the downstream main flow path 6f).

[0026] Furthermore, it is preferable to install the temperature sensor 3 in the lubrication oil flow path 6 between the cooling device 4 (oil cooler 4a) and the fluid machine body (compressor body 1), for example, in the positions of the temperature sensors 3c to 3e shown in the figure.

[0027] The viscosity sensor 2 and the oil temperature sensor 3 are electrically connected to the control device 5 by a wire 5a. The viscosity V of the lubricating oil LO detected by the viscosity sensor 2 and the temperature T of the lubricating oil LO detected by the oil temperature sensor 3 are input to the control device 5 via the wire 5a.

[0028] The control device 5 is a device that controls the operation of the cooling device 4 based on the detected values ​​input from the viscosity sensor 2 and the oil temperature sensor 3, and comprises a storage device 5b and a processing device 5c.

[0029] The storage device 5b consists of RAM (Random Access Memory) and ROM (Read Only Memory), and stores the threshold Vth of the lubricating oil LO at the temperature T shown in Figure 2 (for example, T1, T2, T3 in Figure 2). Preferably, the threshold Vth of the viscosity of the lubricating oil LO is the viscosity V at which the amount of water W contained in the lubricating oil LO is a predetermined value W0 at the temperature T of the lubricating oil LO detected by the oil temperature sensor 3. Furthermore, it is preferable that the predetermined value W0 is the amount of water at which oxidation of the lubricating oil LO is not promoted even if the cooling of the lubricating oil LO is reduced.

[0030] The processing unit 5c can utilize a processor such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit), and executes a process to control the operation of the cooling device 4 based on the viscosity threshold Vth of the lubricating oil LO at a temperature T detected by the oil temperature sensor 3 and the viscosity V detected by the viscosity sensor 2.

[0031] In detail, it is preferable that the control device 5 performs degradation prevention control to reduce the cooling force of the cooling device 4 when the viscosity V detected by the viscosity sensor 2 exceeds the threshold Vth of the lubricating oil LO. Specifically, in degradation prevention control, it is preferable that the control device 5 reduces the flow rate of the cooling fluid (air) supplied to the heat exchanger (oil cooler 4a) (by slowing down or stopping the rotation of the cooling fan 4c).

[0032] Preferably, the control device 5 stores the relationship between the amount of water W contained in the lubricating oil LO and the viscosity V of the lubricating oil LO (see Figure 2) in the storage device 5b for each temperature T of the lubricating oil LO, retrieves the relationship between the amount of water W and viscosity V at the temperature T of the lubricating oil LO detected by the oil temperature sensor 3 from the storage device 5b, and calculates the value at which the amount of water W becomes a predetermined value W0 in that relationship as the threshold value Vth of the lubricating oil LO (by the processing device 5c).

[0033] Furthermore, it is preferable that the control device 5 stores the upper limit temperature Tmax, which is the upper limit of the lubricating oil LO temperature T, in the storage device 5b, and when the lubricating oil LO temperature T detected by the oil temperature sensor 3 exceeds the upper limit temperature Tmax, the deterioration prevention control is stopped (by the processing device 5c) to suppress the rise in the lubricating oil LO temperature T.

[0034] Furthermore, it is preferable that the control device 5 stores (in the storage device 5b) an upper limit time tmax, which is the upper limit of the time t for which the cooling force of the cooling device 4 is reduced, and that (by the processing device 5c) the deterioration prevention control is stopped when the time t for which the cooling force of the cooling device 4 is reduced exceeds the upper limit time tmax, thereby suppressing the rise in the temperature T of the lubricating oil LO.

[0035] Furthermore, the compressed air PA from which the lubricating oil LO has been separated in the gas-liquid separator 1e is discharged into the compressed air passage 7.

[0036] The compressed air passage 7 is a passage that connects the gas-liquid separator 1e and the tank that stores compressed air PA via the aftercooler 4b provided in the cooling device 4, and cools the compressed air PA discharged from the gas-liquid separator 1e before sending it to the tank.

[0037] The aftercooler 4b is an air-cooled heat exchanger that forcibly cools the compressed air PA with the airflow 4d generated by the cooling fan 4c. Alternatively, a water-cooled aftercooler may be used.

[0038] Upstream of the aftercooler 4b in the compressed air passage 7, a pressure regulating check valve 7a is provided to prevent backflow of the fluid and to open when the compressed air PA exceeds a predetermined pressure. The pressure regulating check valve 7a may be mechanical or electrical.

[0039] Furthermore, it is preferable to further provide a drain separator 7b downstream of the aftercooler 4b in the compressed air passage 7, which separates drain from the fluid (compressed air PA) discharged from the fluid machine body (compressor body 1).

[0040] The drain separator 7b includes a drain separation unit that separates drain from the compressed air PA discharged from the compressor body 1 via the gas-liquid separator 1e (for example, by centrifugal force), a drain storage unit that stores the drain separated by the drain separation unit, and a drain discharge unit that discharges the drain from the drain storage unit.

[0041] Furthermore, it is preferable that the drain separator 7b is electrically connected to the control device 5 by a conductor 5a, and that the control device 5 controls the drain discharge section so that the amount of drain discharged from the drain storage section is greater (than when the deterioration prevention control is not performed) when the deterioration prevention control is performed.

[0042] For example, a sensor may be provided to detect the water level and pressure in the drain storage section, and the control device 5 may calculate the amount of drain from the drain storage section from the input values ​​from the sensor and control the solenoid valve provided in the drain discharge section according to that amount of drain. This allows the solenoid valve to be opened according to the increase in drain even if the amount of drain increases when the deterioration prevention control is executed, and the control device 5 can control the drain discharge section so that the amount of drain discharged from the drain storage section is greater than when the deterioration prevention control is not executed when the deterioration prevention control is executed.

[0043] Furthermore, when the deterioration prevention control is performed, the control device 5 may perform control to increase the amount of drain discharged from the drain storage unit by making the solenoid valve open for a longer time, making the solenoid valve closed for a shorter time, or increasing the frequency of opening the solenoid valve, compared to when the deterioration prevention control is not performed.

[0044] Furthermore, it is preferable to provide a dryer 7c downstream of the drain separator 7b to remove moisture contained in the fluid (compressed air PA) discharged from the fluid machine body (compressor body 1).

[0045] The dryer 7c is a device that cools compressed air PA to condense and remove moisture from the compressed air PA. The dryer 7c is equipped with a refrigerant for cooling the compressed air PA, a cooling fan for cooling the refrigerant, and a solenoid valve for discharging the drain accumulated in the dryer 7c, and is electrically connected to the control device 5 by a conductor 5a. When the control device 5 is performing degradation prevention control, it is preferable to operate the dryer 7c in such a way that, when the degradation prevention control is not performed, at least one of the refrigerant flow rate, the rotation speed of the cooling fan, and the time and frequency of opening the solenoid valve are increased compared to when the degradation prevention control is not performed, thereby increasing the amount of moisture removed from the compressed air PA.

[0046] Furthermore, if the temperature of the compressed air PA discharged from the compressor body 1 and flowing through the compressed air passage 7 is too high, there is a risk of component and equipment failure. For this reason, the compressor 100 is configured so that the control device 5 can perform discharge temperature limiter control to limit the temperature of the fluid (compressed air PA) discharged from the fluid machine (compressor 100).

[0047] Specifically, a temperature sensor 8 for detecting the temperature of compressed air PA is provided in the discharge pipe 1d and the compressed air passage 7, and is electrically connected to the control device 5 by a wire 5a. In this embodiment, a first temperature sensor 8a is provided in the discharge pipe 1d, a second temperature sensor 8b is provided in the compressed air passage 7 at a downstream position adjacent to the pressure regulating check valve 7a, a third temperature sensor 8c is provided at an upstream position adjacent to the aftercooler 4b, and a fourth temperature sensor 8d is provided at a downstream position adjacent to the aftercooler 4b.

[0048] When the temperature sensor 8 detects a limit for compressed air PA stored in the memory device 5b, the control device 5 performs a discharge temperature limiter control, for example by reducing the rotational speed of the electric motor 1a, which is electrically connected by the wire 5a, thereby reducing the discharge amount from the compressor body 1, and by increasing the rotational speed of the cooling fan 4c to increase the flow rate of the cooling fluid (air).

[0049] However, if the discharge temperature limiter control is activated while the degradation prevention control is running, the control that reduces the rotation speed of the cooling fan 4c and decreases the flow rate of the cooling fluid, which is performed by the degradation prevention control, is canceled out by the activation of the discharge temperature limiter control. As a result, the reduction of water content in the lubricating oil LO is prevented.

[0050] Therefore, it is preferable for the control device 5 to disable the discharge temperature limiter control, which limits the temperature of the fluid (compressed air PA) discharged from the fluid machine (compressor 100), in the degradation prevention control.

[0051] Preferably, the compressor 100 has a pressure sensor 9 that detects the pressures of air, lubricating oil LO, and compressed air PA. Specifically, it may have a first pressure sensor 9a that detects the pressure of air drawn into the compressor body 1 from the suction filter 1b, a second pressure sensor 9b that detects the pressure inside the gas-liquid separator 1e, a third pressure sensor 9c that detects the pressure of lubricating oil LO drawn into the compressor body 1 from the lubricating oil passage 6, and a fourth pressure sensor 9d that detects the pressure of compressed air PA discharged from the aftercooler 4b.

[0052] Figure 3 shows an example of a control flowchart performed by the control device 5 of a fluid machine according to an embodiment of the present invention.

[0053] The processing unit 5c of the control device 5 performs the processing shown in Figure 3 based on the viscosity threshold Vth (see Figure 2) of the lubricating oil LO at temperature T detected by the oil temperature sensor 3 and the viscosity V detected by the viscosity sensor 2.

[0054] First, the flow shown in Figure 3 begins when the operator initiates the start of the compressor 100.

[0055] Then, in step 1, the control device 5 calculates a threshold Vth for the viscosity V of the lubricating oil LO from the temperature T of the lubricating oil LO input from the temperature sensor 3, and determines whether the viscosity V detected by the viscosity sensor 2 is greater than the threshold Vth (see Figure 2).

[0056] If the viscosity V detected by viscosity sensor 2 is determined to be greater than the threshold viscosity Vth of lubricating oil LO at temperature T detected by oil temperature sensor 3 (YES), proceed to step 2. If the viscosity V detected by viscosity sensor 2 is determined to be less than or equal to the threshold Vth (NO), return to step 1.

[0057] Next, in step 2, the control device 5 performs degradation prevention control to reduce the cooling capacity of the cooling device 4. Specifically, it reduces the flow rate of the cooling fluid (air) supplied to the heat exchanger (oil cooler 4a) by slowing down or stopping the rotation of the cooling fan 4c.

[0058] In this case, it is preferable that the control device 5 disables the discharge temperature limiter control so that the discharge temperature limiter control is not activated even if the detected value of the temperature sensor 8 exceeds the limit stored in the storage device 5b.

[0059] Furthermore, it is preferable that the control device 5 displays an alert on the monitor showing the operating status of the compressor 100 indicating that deterioration prevention control is being performed.

[0060] Next, in step 3, the control device 5 determines whether the temperature T of the lubricating oil LO detected by the oil temperature sensor 3 is equal to or greater than the upper limit temperature Tmax, or whether the time t for reducing the cooling force of the cooling device 4 (duration of deterioration prevention control) is equal to or greater than the upper limit time tmax. This is because the deterioration prevention control raises the temperature of the lubricating oil LO and compressed air PA, which may accelerate the oxidation reaction of the lubricating oil LO and thus accelerate deterioration, or cause failure of parts and equipment. For this reason, it is preferable for the control device 5 (or its memory device 5b) to store the upper limit temperature Tmax of the lubricating oil LO and the upper limit time tmax of the duration t of the deterioration prevention control (in the memory device 5b).

[0061] If the temperature T of the lubricating oil LO detected by the oil temperature sensor 3 is greater than or equal to the upper limit temperature Tmax, or if the duration t of the degradation prevention control is greater than or equal to the upper limit time tmax (YES), proceed to step 4.

[0062] If the temperature T of the lubricating oil LO detected by the oil temperature sensor 3 is not equal to or greater than the upper limit temperature Tmax of the lubricating oil LO, and the duration t of the degradation prevention control is not equal to or greater than the upper limit time tmax (i.e., the temperature T of the lubricating oil LO detected by the oil temperature sensor 3 is less than the upper limit temperature Tmax of the lubricating oil LO, and the duration t of the degradation prevention control is also less than the upper limit time tmax) (NO), return to step 3.

[0063] Next, in step 4, the control device 5 stops the degradation prevention control that reduces the cooling capacity of the cooling device 4. Specifically, it returns the rotation of the cooling fan 4c to the state before the degradation prevention control was executed and restores the flow rate of the cooling fluid (air) supplied to the heat exchanger (oil cooler 4a). At this time, it is preferable for the control device 5 to enable the discharge temperature limiter control that was disabled. It is also preferable for the control device 5 to clear the alert displayed on the monitor showing the operating status of the compressor 100 that the degradation prevention control is being executed when the degradation prevention control is being executed.

[0064] Next, in step 5, the control device 5 determines whether the temperature T of the lubricating oil LO detected by the oil temperature sensor 3 is below the restartable temperature Trs, which is the temperature at which the deterioration prevention control can be restarted.

[0065] If the temperature T of the lubricating oil LO detected by the oil temperature sensor 3 is less than or equal to the restartable temperature Trs (YES), return to step 1. If the temperature T of the lubricating oil LO detected by the oil temperature sensor 3 exceeds the restartable temperature Trs (NO), return to step 5.

[0066] These steps 1 through 5 are repeated until the operator stops the compressor 100.

[0067] [effect] The compressor 100 according to this embodiment includes a fluid machine body 1 that discharges fluid, lubricating oil LO that flows through the fluid machine body 1, a viscosity sensor 2 that detects the viscosity V of the lubricating oil LO, an oil temperature sensor 3 that detects the temperature T of the lubricating oil LO, a cooling device 4 that cools the lubricating oil LO, and a control device 5 that controls the operation of the cooling device 4 based on the viscosity threshold Vth of the lubricating oil LO at the temperature T of the lubricating oil LO detected by the oil temperature sensor 3 and the viscosity V detected by the viscosity sensor 2. Therefore, the operation of the cooling device can be controlled based on the amount of water contained in the lubricating oil, which can be determined from the viscosity of the lubricating oil, and the amount can be reduced, thereby preventing deterioration of the lubricating oil caused by an increase in the amount of water contained in the lubricating oil.

[0068] In this embodiment, the control device 5 of the compressor 100 preferably performs deterioration prevention control by reducing the cooling force of the cooling device 4 when the viscosity V detected by the viscosity sensor 2 exceeds the viscosity threshold Vth of the lubricating oil LO. Therefore, in the compressor 100 of this embodiment, when the viscosity threshold Vth of the lubricating oil LO is exceeded, it is determined that the amount of water contained in the lubricating oil LO will deteriorate the lubricating oil LO, and deterioration prevention control is performed by reducing the cooling force of the cooling device 4 to raise the temperature of the lubricating oil LO, thereby reducing the amount of water contained in the lubricating oil LO by evaporation. This makes it possible to prevent deterioration caused by the presence of water in the lubricating oil LO.

[0069] In this embodiment, the viscosity threshold Vth of the lubricating oil LO, which the control device 5 of the compressor 100 uses as the basis for controlling the operation of the cooling device 4, is preferably a viscosity V at which the amount of water contained in the lubricating oil LO is a predetermined value W0 at the temperature T of the lubricating oil LO detected by the oil temperature sensor 3. This predetermined value W0 is preferably the amount of water at which the performance of the lubricating oil LO begins to deteriorate and the risk of degradation increases. This makes it possible to suppress the deterioration and degradation of the lubricating oil LO.

[0070] In this embodiment, the control device 5 of the compressor 100 preferably stores the relationship between the amount of water W contained in the lubricating oil LO and the viscosity V of the lubricating oil LO (in the storage device 5b) for each temperature T of the lubricating oil LO, retrieves the relationship between the amount of water W and viscosity V at the temperature T of the lubricating oil LO detected by the oil temperature sensor 3 (from the storage device 5b), and calculates (by the processing device 5c) the value at which the amount of water W becomes a predetermined value W0 in that relationship as the viscosity threshold Vth of the lubricating oil LO. Preferably, this predetermined value W0 is the amount of water at which the performance of the lubricating oil LO begins to deteriorate and the risk of degradation increases. This allows for degradation prevention control to be performed based on the real-time temperature T and viscosity V detected values ​​of the lubricating oil LO, and enables accurate prevention of degradation caused by the presence of water in the lubricating oil LO.

[0071] In this embodiment, the control device 5 of the compressor 100 preferably stores the upper limit temperature Tmax, which is the upper limit of the temperature T of the lubricating oil LO, in the storage device 5b, and stops the deterioration prevention control when the temperature T of the lubricating oil LO detected by the oil temperature sensor 3 exceeds the upper limit temperature Tmax. This suppresses the risk of oxidation and ignition of the lubricating oil LO and suppresses failure of parts that come into contact with the lubricating oil LO (oil cooler, three-way valve, oil filter, bearings, gears, etc.).

[0072] In this embodiment, the control device 5 of the compressor 100 preferably stores an upper limit time tmax (in the storage device 5b), which is the upper limit of the time t for which the deterioration prevention control is continuously executed, and stops the deterioration prevention control when the time t for which the deterioration prevention control is continuously executed exceeds the upper limit time tmax. This suppresses the risk of oxidation and ignition of the lubricating oil LO and suppresses failure of parts that come into contact with the lubricating oil LO (oil cooler, three-way valve, oil filter, bearings, gears, etc.).

[0073] The compressor 100 according to this embodiment further includes a drain separator 7b having a drain separation section for separating drain from the fluid (compressed air PA) discharged from the main body of the machine 1, a drain storage section for storing the drain separated by the drain separation section, and a drain discharge section for discharging drain from the drain storage section. Preferably, when the deterioration prevention control is executed, the control device 5 controls the drain discharge section (for example, a solenoid valve that discharges drain) so that the amount of drain discharged from the drain storage section increases. This makes it possible to suppress the overflow of the drain from the drain storage section of the drain separator 7b due to the increased amount of drain caused by the deterioration prevention control.

[0074] The compressor 100 according to this embodiment further includes a dryer 7c that removes moisture contained in the fluid discharged from the fluid machine body 1, and the control device 5 preferably operates the dryer 7c in such a way that more moisture is removed when the deterioration prevention control is executed. Specifically, when the deterioration prevention control is executed, the control device 5 preferably increases at least one of the refrigerant flow rate, the cooling fan rotation speed, and the time and frequency of opening the solenoid valve compared to when the deterioration prevention control is not executed, and operates the dryer 7c in such a way that more moisture is removed from the compressed air PA.

[0075] Since the amount of moisture contained in the fluid (compressed air PA) discharged from the fluid machine body (compressor body 1) increases when deterioration prevention control is performed compared to when deterioration prevention control is not performed, the increase in the amount of moisture contained in the fluid (compressed air PA) discharged from the fluid machine (compressor 100) can be suppressed by increasing the operating rate of the dryer 7c. Specifically, the control to increase the operating rate of the dryer 7c is to increase, for example, the refrigerant flow rate, the rotation speed of the cooling fan, and at least one of the opening time and frequency of the solenoid valve in the dryer 7c compared to when deterioration prevention control is not performed.

[0076] The compressor 100 according to this embodiment has a lubricating oil passage 6 that separates the lubricating oil LO contained in the fluid (compressed air PA) discharged from the fluid machine body (compressor body 1) and returns it to the fluid machine body (compressor body 1). The viscosity sensor 2 consists of multiple viscosity sensors 2a to 2e, and the oil temperature sensor 3 consists of multiple oil temperature sensors 3a to 3e. Preferably, each of the multiple viscosity sensors 2a to 2e and the multiple oil temperature sensors 3a to 3e are provided at different positions in the lubricating oil passage 6. This makes it possible to grasp the amount of moisture in the lubricating oil LO at each position in the lubricating oil passage 6, and to perform deterioration prevention control effectively or at a desired time.

[0077] The compressor 100 according to this embodiment is equipped with a lubricating oil passage 6 that cools the lubricating oil LO separated from the fluid (compressed air PA) discharged from the fluid machine body (compressor body 1) using a cooling device 4 and returns it to the fluid machine body (compressor body 1). Preferably, the viscosity sensor 2 and the oil temperature sensor 3 are located in the lubricating oil passage 6 between the cooling device 4 and the fluid machine body (compressor body 1).

[0078] The lower the temperature T in the lubricating oil LO and the higher the viscosity V of the lubricating oil LO, the greater the change in viscosity V due to the amount of water contained in the lubricating oil LO. Therefore, in order to accurately determine the amount of water contained in the lubricating oil LO, the position after passing through the cooling device 4 is preferable as the mounting position for the viscosity sensor 2 and the oil temperature sensor 3. This allows for accurate determination of the amount of water in the lubricating oil LO, and enables effective or desirable execution of deterioration prevention control.

[0079] In this embodiment, the cooling device 4 of the compressor 100 has a heat exchanger (oil cooler 4a) for cooling the lubricating oil LO, and the control device 5 preferably reduces the flow rate of the cooling fluid (airflow 4d generated by the cooling fan 4c) supplied to the heat exchanger (oil cooler 4a) (compared to when the deterioration prevention control is not performed) in the deterioration prevention control. This makes it easy to suppress the cooling of the lubricating oil LO when the deterioration prevention control is performed.

[0080] In this embodiment, the control device 5 of the compressor 100 preferably disables the discharge temperature limiter control, which limits the temperature of the fluid (compressed air PA) discharged from the fluid machine (compressor 100), in the degradation prevention control. This prevents the degradation prevention control from being hindered by the discharge temperature limiter control.

[0081] It should be noted that the present invention is not limited to the embodiments described above, and various modifications are included. For example, the embodiments described above are described in detail to make the present invention easier to understand, and are not necessarily limited to those having all the configurations described. Furthermore, it is possible to replace parts of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add configurations from other embodiments to the configuration of one embodiment. In addition, it is possible to add, delete, or replace parts of the configuration of each embodiment with other configurations.

[0082] Embodiments of the present invention may also be as follows. The above embodiments show a configuration in which the fluid machine is a compressor, but are not limited to this. For example, a vacuum pump may be used as the fluid machine. Similar to the compressor 100, the vacuum pump generates heat in the process of compressing air, and this heat can be used to heat the lubricating oil inside the vacuum pump, thereby preventing deterioration of the lubricating oil by evaporating the water contained in the oil. [Explanation of Symbols]

[0083] 1…Compressor body, 1e…Gas-liquid separator, 2,2a~2e…Viscosity sensor, 3,3a~3e…Oil temperature sensor, 4…Cooling device, 4a…Oil cooler, 4b…Aftercooler, 4c…Cooling fan, 4d…Airflow, 5…Control device, 5a…Wiring, 5b…Memory device, 5c…Processing device, 6…Lubricating oil flow path, 6a…Temperature control valve, 6c…Oil cooling flow path, 6d…Bypass flow path, 6e…Confluence section, 7…Compressed air flow path, 7b…Drain separator, 7c…Dryer, 8,8a~8d…Temperature sensor, 100…Fluid machine (compressor)

Claims

1. A fluid machine body that discharges fluid, The lubricating oil that flows through the main body of the fluid machine, A viscosity sensor for detecting the viscosity of the lubricating oil, The oil temperature sensor for detecting the temperature of the lubricating oil, A cooling device for cooling the lubricating oil, A fluid machine comprising a control device that controls the operation of the cooling device based on a threshold value of the viscosity of the lubricating oil at the temperature of the lubricating oil detected by the oil temperature sensor and the viscosity detected by the viscosity sensor.

2. A fluid machine according to claim 1, The control device is characterized in that, when the viscosity detected by the viscosity sensor exceeds a threshold for the viscosity of the lubricating oil, it performs deterioration prevention control to reduce the cooling force of the cooling device.

3. A fluid machine according to claim 1, The fluid machine is characterized in that the viscosity threshold of the lubricating oil is such that, at the temperature of the lubricating oil detected by the oil temperature sensor, the amount of water contained in the lubricating oil is a predetermined value.

4. A fluid machine according to claim 1, The control device stores the relationship between the amount of water contained in the lubricating oil and the viscosity of the lubricating oil for each temperature of the lubricating oil, retrieves the relationship between the amount of water and the viscosity at the temperature of the lubricating oil detected by the oil temperature sensor, and calculates a threshold value for the viscosity of the lubricating oil at which the amount of water in that relationship becomes a predetermined value.

5. A fluid machine according to claim 2, The control device stores an upper limit temperature, which is the upper limit of the lubricating oil temperature, and stops the deterioration prevention control when the temperature of the lubricating oil detected by the oil temperature sensor exceeds the upper limit temperature.

6. A fluid machine according to claim 2, The control device stores an upper limit time, which is the maximum time for which the deterioration prevention control is to be continuously executed, and stops the deterioration prevention control when the time for which the deterioration prevention control is to be continuously executed exceeds the upper limit time.

7. A fluid machine according to claim 2, The drain separator further comprises a drain separation section for separating drain from the fluid discharged from the fluid machine body, a drain storage section for storing the drain separated by the drain separation section, and a drain discharge section for discharging drain from the drain storage section. The control device is characterized in that, when the deterioration prevention control is executed, it controls the drain discharge unit so that the amount of drain discharged from the drain storage unit increases.

8. A fluid machine according to claim 2, The system further includes a dryer that removes moisture contained in the fluid discharged from the fluid machine body, The control device is characterized in that, when the deterioration prevention control is executed, it operates the dryer in such a way that a large amount of moisture is removed.

9. A fluid machine according to claim 1, The system has a lubricating oil path that separates the lubricating oil contained in the fluid discharged from the fluid machine body and returns it to the fluid machine body. The viscosity sensor comprises multiple viscosity sensors, and the oil temperature sensor comprises multiple oil temperature sensors. A fluid machine characterized in that each of the plurality of viscosity sensors and the plurality of oil temperature sensors is provided at different locations in the lubricating oil path.

10. A fluid machine according to claim 1, The system includes a lubricating oil path that has a route for cooling the lubricating oil separated from the fluid discharged from the fluid machine body using the cooling device and returning it to the fluid machine body, A fluid machine characterized in that the viscosity sensor and the oil temperature sensor are provided in the lubrication oil path between the cooling device and the fluid machine body.

11. A fluid machine according to claim 2, The cooling device has a heat exchanger for cooling the lubricating oil, The control device is characterized in that, in the deterioration prevention control, it reduces the flow rate of the cooling fluid supplied to the heat exchanger.

12. A fluid machine according to claim 2, The control device is characterized in that, in the deterioration prevention control, it disables the discharge temperature limiter control that limits the temperature of the fluid discharged from the fluid machine.

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