Lubricant diagnostic method, lubricant diagnostic device, and lubricant diagnostic system

Abstract

To provide a technology capable of easily determining the generation of sludge and burnish in oil.SOLUTION: A diagnostic method for lubrication oil containing an additive to be used in a machine prepares at least one piece of information based on a result due to total acid value measurement of lubrication oil acquired separately in advance, a result due to sludge and burnish generation amount measurement of the lubrication oil acquired separately in advance, and a result due to optical measurement of the lubrication oil acquired separately in advance, and can convert at least one data selected from among data based on the result of the total acid value measurement of the lubrication oil containing an additive to be used in the machine, data based on the result due to the sludge and burnish generation amount measurement of the lubrication oil containing the additive to be used in the machine, and data based on the result due to the optical measurement of the lubrication oil containing the additive to be used in the machine, on the basis of the information.SELECTED DRAWING: Figure 11

Description

[Technical Field]

[0001] The present invention relates to a lubricating oil and a diagnostic method and diagnostic system for a machine that uses the lubricating oil, and in particular to a remaining life diagnosis of the lubricating oil. [Background technology]

[0002] For example, diagnosing the properties of lubricants used in bearings, gears, and other rotating parts is an important technology when maintaining large rotating machinery. Examples of large rotating machinery include wind turbine gearboxes, air compressors, ships, and power generation turbines. Depending on the purpose of use, lubricants are classified into engine oil, turbine oil, hydraulic oil, bearing oil, sliding surface oil, gear oil, compressor oil, cutting oil, and other types.

[0003] Figure 1 shows a list of additives added to various lubricating oils. As shown in Figure 1, various additives are blended into each lubricating oil to ensure that it meets the required performance.

[0004] Regarding lubricant performance assessment, Patent Document 1 discloses a method for assessing the sludge generation potential of new oil. Patent Document 2 discloses a lubricant degradation estimation method that includes filtering lubricant used in a rotating machine through a membrane filter, acquiring color information about the filter, and estimating the RPVOT remaining rate of the lubricant based on the color information acquired in the color measurement process and a calibration curve created in a creation process. Patent Document 3 also discloses outputting the color of the lubricant as sensor information and judging the degree of abnormality of the lubricant and the gearbox based on the sensor information and a reference value established for each sensor information. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-35706 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-20864 [Patent Document 3] Japanese Patent Publication No. 2020-12690 Summary of the Invention [Problem to be solved by the invention]

[0006] In recent years, machine condition monitoring has often adopted a strategy to minimize the lifecycle cost of the machine. Large machines such as power generation turbines use large amounts of lubricating oil, and lubricating oil changes require the machine to be stopped, which has negative aspects such as power generation losses and production stoppages. In addition, it requires costs such as purchasing and shipping new oil, oil change labor costs, and oil disposal costs, so it is desirable to use the lubricating oil for as long as possible. Lubricating oil quality assessment can be broadly divided into two types: (1) oxidative deterioration of lubricating oil over time, and (2) contamination by external contaminants such as water, dust, and wear particles.

[0007] (1) Oxidative degradation of lubricating oil is known to occur as a result of the consumption of antioxidants contained as additives, followed by oxidation of the base oil. Oxidative degradation of lubricating oil leads to a decrease in wear resistance, changes in viscosity and viscosity index, a decrease in rust prevention properties, and a decrease in corrosion prevention properties. As a result, wear and material fatigue in gearboxes can be accelerated.

[0008] The increase in acidity associated with oxidative deterioration of lubricating oil is observed as an increase in the total acid number. As oxidation of lubricating oil progresses, lubricating oil deterioration products precipitate in the oil, and organic deposits called sludge or varnish (also known as varnish) may form. The formation of sludge or varnish increases the likelihood of machine failure. For example, valves and bearings may stick, and oil filters and piping may become clogged. This can result in valve failure, orifice clogging, bearing wear, and reduced oil cooler performance. Sludge and varnish are unstable in oil, and can accelerate deterioration and deposit in areas of the machine where local overheating occurs, or precipitate suddenly in low-temperature areas.

[0009] Patent Document 1 discloses a technique for measuring the amount of sludge formation in oil. It involves conducting an oxidation degradation test to determine the RPVOT (Rotating Pressure Vessel Oxidation) remaining rate of lubricating oil that has been forcibly degraded, and then assessing the sludge formation in the lubricating oil. RPVOT is a test method recommended as one of the control items in ASTM D4378, which deals with the management of the degree of degradation of lubricating oil. It indicates the time (induction time) until the lubricating oil being measured begins to rapidly absorb oxygen. ASTM D4378 defines the RPVOT remaining rate as the RPVOT value of degraded oil divided by the RPVOT value of new oil, and recommends that the RPVOT remaining rate be maintained at 25% or higher. Note that RBOT (Rotating Bomb Oxidation Stability Test) is the former name for RPVOT, and they have the same meaning.

[0010] Patent Document 2 describes a method for estimating the degree of deterioration of lubricating oil by filtering deteriorated lubricating oil through a filter and measuring the color remaining on the filter.

[0011] (2) Lubricating oil contamination occurs due to water, dust, and wear particles generated by rotating parts. Water contamination causes a decrease in lubricating performance due to changes in the viscosity of the lubricating oil, and leads to corrosion, rust, and material deterioration of metal parts. Dust itself rarely causes fatal breakdowns, but it can cause an increase in metal wear particles. Wear particles are known to cause fatal breakdowns of machinery depending on their size.

[0012] The lubricating oil of rotating machinery such as gas turbines and gearboxes is sometimes monitored by sampling small amounts at predetermined intervals and sending them to an analysis center, where the viscosity, contamination level, total acid number, metal concentration, etc. are analyzed. In addition, status monitoring is performed using a group of sensors (for example, sensors for output, generator rotation speed, power generation, oil temperature, oil pressure, acceleration, etc.) installed in wind turbines, power plants, engines, etc.

[0013] Conventionally, as a technique for diagnosing the properties of lubricating oil, for example, Patent Document 3 shows that the reduction (degree of consumption) of additives in lubricating oil, which is an indicator of lubricating oil deterioration, can be determined from the color measured by an optical sensor.

[0014] When it comes to oil maintenance for large machinery, standards and various standardized measurement methods are often established for viscosity, total acid number, water content, contamination level (mass method or ISO code), and elemental concentrations such as iron, copper, and phosphorus. For example, known control standards for viscosity are within 10% of the viscosity of new oil, total acid number is 0.2 mg KOH / g or less, water content is 200 ppm or less, and contamination level (mass method) is 10 mg / g or less. Control standards vary depending on the type of machine, type of lubricant product, etc.

[0015] Recent improvements in the quality of lubricating oils, especially base oils, have made viscosity less susceptible to changes over time and improved viscosity indexes, leading to a trend toward emphasis on the total acid number and contamination level as lubricating oil management indicators.

[0016] Lubricating oils contain various additives to maintain their lubricating performance. For example, when the lubrication conditions are severe, such as when the pressure at the contact points is high, the sliding speed is low, or the oil viscosity is too low, the lubricating oil film between the friction surfaces becomes thin, increasing frictional resistance and causing wear. This condition is called boundary lubrication, and in extreme cases, seizure can occur. Additives, such as oiliness agents, anti-wear agents, and extreme-pressure additives (extreme-pressure agents), work to reduce friction and wear under such boundary lubrication conditions. These additives are sometimes collectively referred to as load-bearing additives. Other additives include antioxidants and antifoaming agents. Additives must be present in a specific proportion (concentration) of the lubricating oil to maintain the desired lubricating performance.

[0017] Lubricants are composed of base oils that form an optimal lubricating film for machinery, and additives that improve functions such as lubrication, extreme pressure resistance, rust prevention, and anti-foaming. Almost all lubricants contain antioxidants, which prevent a decrease in lubrication due to oxidation of the base oil and an increase in the risk of rust and corrosion due to an increase in the acidity of the lubricant. However, if the antioxidant concentration falls below a certain level, the viscosity and acidity of the lubricant will rise sharply.

[0018] Problems with lubricating oil include sludge and varnish (also called varnish). Both sludge and varnish are decomposition products that are formed when components of lubricating oil are oxidized and precipitate in the oil.

[0019] Sludge has several definitions, but it is a substance that turns into a mud-like substance after long-term use of lubricating oil. It is a general term for impurities that have been mixed into the oil and precipitated, as well as products of lubricating oil deterioration that can no longer be dissolved.

[0020] There are several definitions of varnish, but it is a sticky oil film of dirt that forms on metal surfaces. In lubricating oils, varnish is a type of sludge, formed when precursors produced by the degradation of additives polymerize and form an adsorbed film on the metal surface. Unlike sludge, varnish forms a hard film that can be difficult to remove.

[0021] Both of these are known to cause malfunctions in machinery that uses lubricating oil. For example, problems have arisen such as valve tripping (not moving according to control instructions) and bearing malfunctions. Sludge and varnish tend to precipitate in areas where lubricating oil is cooled, so they precipitate in the piping and tanks of the cooling system. Furthermore, even if the temperature is high during operation, when the temperature drops during shutdown, oil degradation products precipitate, causing malfunctions when the machinery is restarted.

[0022] The formation of sludge and varnish is accelerated by local overheating within the machine. For example, lubricating oil dissolves a few percent of air. Pressurization and release of pressure within the machine causes the formation of bubbles and adiabatic compression of the bubbles. It is known that local overheating occurs due to pressure differences in compressed air, leading to the formation of precursors to sludge and varnish. Temperatures can rise to over 500°C, enough to carbonize the lubricating oil in an instant, but this cannot be observed by temperature measurements on the machine. It is also known that static electricity is generated and electrostatic discharge occurs when the flow rate of lubricating oil is high in filters and piping. Electrostatic discharge poses the issue of localized temperatures reaching over 1000°C, making varnish more likely to form.

[0023] For example, in the case of gas turbines, the combustion temperature of gas turbines is rising, requiring turbine oils to have thermal stability (oxidation stability). Oil volume is decreasing, requiring even higher oxidation stability. To improve oxidation stability, highly refined base oils and synthetic base oils are being used, but base oils with high oxidation stability tend to be prone to varnish formation. This is because varnish is formed by the precipitation of oxidative decomposition products of oil components, and base oils with high oxidation stability have low solubility for varnish and varnish precursors.

[0024] While it is desirable to use lubricating oil for as long as possible, if abnormal deterioration or contamination is detected, the oil must be changed promptly and the equipment must be inspected. This has made it necessary to predict when sludge and varnish will form in the oil, but this has not previously been easy to predict.

[0025] The RPVOT method, which is a method for predicting sludge and varnish formation in oil, has the problem that it requires a long time in the laboratory to obtain results.

[0026] Additionally, as an indicator of the amount of sludge and varnish generated in the oil, there are methods such as filtering the lubricating oil and measuring the weight of the solids, or filtering it through a filter, drying the filter, and measuring the coloration, but both of these require the lubricating oil to be sampled from the machine and evaluated in a laboratory or office, and there is no way to perform real-time measurement using a machine.Measuring the contamination level of lubricating oil (mass method) is significant in that it measures the amount of sludge and varnish precursors, but because it requires filtering, it is difficult to easily obtain results on the spot where the oil is sampled, and there are also issues with not being able to perform online measurement.

[0027] It is necessary to optimize the lubricant replacement cycle by monitoring the consumption of additives such as antioxidants in the lubricant and the increase in the lubricant's acidity while the machine is in use, determining the remaining life of the lubricant, and continuing to operate the machine without changing the lubricant if the lubricant is in good condition, or by changing the lubricant earlier if the lubricant's condition is poor.

[0028] Therefore, an object of the present invention is to provide a technology that can easily determine the formation of sludge and varnish in oil. [Means for solving the problem]

[0029] One aspect of the present invention is a diagnostic method for lubricating oil containing additives used in a machine, comprising: preparing at least one piece of information selected from among information showing the relationship between the first result and the second result, information showing the relationship between the first result and the third result, and information showing the relationship between the second result and the third result, based on a first result which is the result of a measurement of the total acid number of the lubricating oil obtained separately in advance, a second result which is the result of a measurement of the amount of sludge and varnish produced by the lubricating oil obtained separately in advance, and a third result which is the result of an optical measurement of the lubricating oil obtained separately in advance; and, based on the information, being capable of converting at least one piece of data selected from among first data based on the result of the measurement of the total acid number of the lubricating oil containing additives used in the machine, second data based on the result of a measurement of the amount of sludge and varnish produced by the lubricating oil containing additives used in the machine, and third data based on the result of the optical measurement of the lubricating oil containing additives used in the machine.

[0030] A more specific example is to do at least one of the following: setting a first threshold value, which is a threshold value of the total acid number for controlling the amount of sludge and varnish produced, based on information showing the relationship between the first result and the second result; and setting a second threshold value, which is a threshold value of the optical measurement result for controlling the amount of sludge and varnish produced, based on information showing the relationship between the first result and the second result and information showing the relationship between the first result and the third result.

[0031] A more specific example is a diagnostic device for lubricating oil containing additives used in a machine, the diagnostic device for lubricating oil comprising a memory device that stores at least one of the first threshold value and the second threshold value, a sensor that acquires third data based on the results of optical measurement of the lubricating oil containing additives used in the machine, and the third data, either directly or converted, is compared with at least one of the first threshold value and the second threshold value, and displays or notifies based on the comparison result.

[0032] Another preferred aspect of the present invention is a diagnostic device for lubricating oil containing additives used in a machine, comprising: a correlation database that records at least one of information indicating the relationship between a first result obtained by measuring the total acid number of the lubricating oil separately obtained in advance, a second result obtained by measuring the amount of sludge and varnish produced by the lubricating oil separately obtained in advance, and a third result obtained by optical measurement, based on the first result and the third result, and information indicating the relationship between the second result and the third result; and a data conversion unit that performs, based on the information, conversion between at least one data selected from first data based on the result of measuring the total acid number of the lubricating oil containing additives used in the machine and second data based on the result of measuring the amount of sludge and varnish produced by the lubricating oil containing additives used in the machine, and third data based on the result of optical measurement of the lubricating oil containing additives used in the machine.

[0033] Another preferred aspect of the present invention is a diagnostic system for lubricating oil containing additives used in machinery, comprising: an optical sensor that acquires color information of the lubricating oil; at least one database selected from a first database that stores the total acid number of the lubricating oil and a second database that stores a measured amount of sludge and varnish production of the lubricating oil; a data conversion unit that derives at least one of the total acid number and the measured amount of sludge and varnish production from the color information; and a correlation database referenced by the data conversion unit, wherein the correlation database contains at least one of information indicating the relationship between a first result, which is a predetermined total acid number quantification result, and a third result, which is color information of the lubricating oil obtained in advance by optical measurement, and information indicating the relationship between a second result, which is a predetermined measured amount of sludge and varnish production, and the third result. [Effects of the Invention]

[0034] According to the present invention, it is possible to provide a technology that can easily determine the generation of sludge and varnish in oil. Problems, configurations, and effects other than those described above will become clear from the following description of the embodiments. [Brief explanation of the drawings]

[0035] [Figure 1] 1 is a table showing types of additives for various lubricants. [Figure 2] Schematic overall configuration diagram of a downwind type wind turbine generator. [Figure 3] FIG. 10 is a graph showing the relationship between contamination level and time. [Figure 4] Graph showing the relationship between total acid number and time. [Figure 5] Graph showing the relationship between contamination level and ΔE. [Figure 6] A graph showing the relationship between the contamination level and B. [Figure 7] Graph showing the relationship between total acid number and ΔE. [Figure 8] Graph showing the relationship between total acid number and B. [Figure 9] Schematic diagram of a wind turbine lubricant oil monitoring system. [Figure 10] Conceptual diagram of a rotating machine equipped with a lubricant sensor. [Figure 11] FIG. 4 is a flow chart showing a lubricant diagnosis process according to an embodiment. [Figure 12] FIG. 2 is a functional block diagram of a central server according to an embodiment. [Figure 13] FIG. 2 is a graph showing the relationship between the total acid number and time of the lubricating oils of the examples. [Figure 14] FIG. 2 is a graph showing the relationship between the total acid number and ΔE of the lubricating oils of the examples. [Figure 15] FIG. 2 is a graph showing the relationship between total acid number and time in the examples. [Figure 16] FIG. 10 is a graph showing the relationship between ΔE and time in an example. [Figure 17] 1 is a configuration diagram showing an embodiment of a gas turbine. [Figure 18] FIG. 2 is a graph showing the results of a preliminary calculation of the correlation between the total acid number and color coordinate (ΔE) of turbine oil. [Figure 19] A graph showing the results of continuous oil color measurements using an optical sensor in a gas turbine. [Figure 20] This is a diagram showing the configuration when a branch flow path is provided in the oil flow path of a gas turbine and an optical sensor is installed therein. [Figure 21] A conceptual diagram showing the relationship between viscosity, total acid number, antioxidant concentration, and amount of sludge and varnish. DETAILED DESCRIPTION OF THE INVENTION

[0036] For example, equipment such as wind turbines must operate stably at a high level for long periods, so it is necessary to monitor the properties of the lubricating oil over the long term and monitor the formation of sludge in the lubricating oil.In equipment that previously monitored the properties of lubricating oil by collecting oil samples and measuring the color of the filter paper after filtering it, it was difficult to collect oil samples and measure the filter paper frequently every day, making it difficult to guarantee the continuity of measurement data over time.

[0037] When there is sufficient antioxidant remaining in the lubricating oil, the antioxidant functions well and the rate of sludge and varnish formation is low, but as the amount of antioxidant remaining decreases, the formation of sludge and varnish is thought to accelerate. In other words, as the antioxidant concentration decreases, the total acid number of the lubricating oil increases, and the acidity of the lubricating oil increases, accelerating the formation of sludge and varnish.

[0038] Thus, an increase in the total acid number leads to an increased risk of sludge and varnish formation and an increased risk of rust and corrosion of parts. Furthermore, the degree of contamination is positively correlated with the concentration of sludge and varnish precursors.

[0039] Therefore, it is believed that the occurrence of sludge and varnish can be indirectly monitored by monitoring the decrease in antioxidant concentration in lubricating oil, the increase in total acid number, the increase in viscosity, etc. It is also believed that it is possible to predict when the occurrence of sludge and varnish will increase sharply.

[0040] In a typical embodiment described in the examples, the remaining life of a lubricant is assessed using data from an optical sensor capable of measuring the color coordinate of the lubricant, based on a calibration curve previously prepared using new and used, deteriorated lubricants of the same type, which shows the correlation between the measurement results of the rate of increase in total acid number and the rate of increase in contamination level (mass method) and the color coordinate of new and used, deteriorated lubricants. This ensures data continuity without the need for oil sampling and filtering using filter paper, thereby providing a highly reliable remaining life assessment technology. The total acid number of the lubricant was measured by indicator titration or potentiometric titration after sampling the lubricant in advance.

[0041] A preferred example of this embodiment is a diagnostic method for lubricating oil containing additives used in machinery, in which the amount of sludge and varnish produced in the lubricating oil is determined by optical measurement of the lubricating oil using a correlation function between the color of the lubricating oil and the total acid number, which has been determined separately in advance.

[0042] Another example is a lubricant diagnostic method characterized by preparing information showing the relationship between the first result and the second result, which is the result of measuring the total acid number of the lubricant or the result of measuring the amount of antioxidant remaining in the lubricant, and the second result, which is the result of optical measurement obtained separately in advance, and converting the first data, which is based on the result of measuring the total acid number of the lubricant used in the machine or the result of measuring the amount of antioxidant remaining in the lubricant, and the second data, which is based on the result of optical measurement of the lubricant containing the additive used in the machine, based on the information, to predict the generation of sludge and varnish in the lubricant.

[0043] Yet another example is a diagnostic device for lubricating oil containing additives used in machines, which is characterized by having a correlation database that records information showing the relationship between a first result, which is a result of a total acid number measurement obtained separately in advance, or a result of measuring the remaining amount of antioxidants in the lubricating oil, and a second result, which is a result of optical measurement obtained separately in advance, and a data conversion unit that converts, based on the information, the first data based on the total acid number result of the lubricating oil containing additives used in the machine or the result of measuring the remaining amount of antioxidants in the lubricating oil, and the second data based on the result of optical measurement of the lubricating oil containing additives used in the machine, and is characterized by having: a correlation database that records information showing the relationship between a first result and a second result, which is a result of an optical measurement of the lubricating oil containing additives used in the machine, and a data conversion unit that converts, based on the information, the first data based on the total acid number result of the lubricating oil containing additives used in the machine or the result of measuring the remaining amount of antioxidants in the lubricating oil, and a data conversion unit that converts, based on the information, the second data based on the result of optical measurement of the lubricating oil containing additives used in the machine, and is characterized by predicting the generation of sludge and varnish in the lubricating oil.

[0044] Another example is a diagnostic system for lubricating oil containing additives used in machinery, comprising an optical sensor that acquires color information of the lubricating oil, a database that stores a function for predicting sludge and varnish formation in the lubricating oil using the total acid number measurement results of the lubricating oil or the measurement results of the remaining amount of antioxidant in the lubricating oil, a data conversion unit that derives the amount of the additive from the color information, and a correlation database referenced by the data conversion unit, wherein the correlation database contains information indicating the relationship between a first result, which is the total acid number measurement result of the lubricating oil or the measurement results of the remaining amount of antioxidant in the lubricating oil, and a second result, which is color information of the lubricating oil obtained in advance by optical measurement.

[0045] According to this embodiment, it is possible to predict when sludge and varnish will form in the lubricating oil of machines such as gas turbines, wind power generators, and air compressors, and a highly reliable remaining life assessment technology can be provided. Issues, configurations, and effects other than those described above will be made clear through the description of the embodiment below.

[0046] Wind turbines use lubricants and the like to reduce the mechanical coefficient of friction between their components. In the following examples, a lubricant remaining life assessment technique will be described using the lubricant in a wind turbine as an example. One example described in the examples is a wind turbine diagnostic system that collects information from a wind turbine having a gearbox and a generator, and determines abnormalities in the wind turbine based on the collected information. To monitor the state of the wind turbine, this system has a sensor that outputs sensor information indicating the properties of the lubricant supplied to the gearbox, and a memory unit that stores reference values ​​determined for each piece of sensor information.

[0047] <Basic configuration of a wind turbine> Figure 2 shows a schematic overall configuration diagram of a downwind wind turbine as an example of a machine to be monitored. In Figure 2, each piece of equipment arranged inside a nacelle 3 is indicated by a dotted line. As shown in Figure 2, the wind turbine 1 includes blades 5 that rotate when exposed to wind, a hub 4 that supports the blades 5, the nacelle 3, and a tower 2 that supports the nacelle 3 so that it can rotate in a horizontal plane.

[0048] The nacelle 3 is equipped with a main shaft 31 connected to the hub 4 and rotating together with the hub 4, a shrink disk 32 connected to the main shaft 31, a speed increaser 33 connected to the main shaft 31 via the shrink disk 32 and increasing the rotational speed, and a generator 34 which generates electricity by rotating the rotor at the rotational speed increased by the speed increaser 33 via a coupling 38.

[0049] The part that transmits the rotational energy of the blades 5 to the generator 34 is called the power transmission part, and the power transmission part includes the main shaft 31, shrink disk 32, speed increaser 33, and coupling 38. The speed increaser 33 and generator 34 are held on a main frame 35.

[0050] Furthermore, one or more lubricating oil tanks 37 that store lubricating oil for lubricating the power transmission parts are installed on the main frame 35. Furthermore, a radiator 36 is arranged inside the nacelle 3 on the upwind side of the nacelle bulkhead 30. Cooling water cooled in the radiator 36 using outside air is circulated to the generator 34 and the gearbox 33 to cool the generator 34 and the gearbox 33. Although Fig. 2 has been explained using a so-called downwind type wind turbine as an example, it goes without saying that this embodiment can also be applied to an upwind type wind turbine.

[0051] Lubricating oil is used in many rotating machines in wind turbines. For example, in Figure 2, lubricating oil is supplied to the main shaft 31, gearbox 33, generator 34, and yaw and pitch bearings (not shown). Blade pitch control controls the output by changing the pitch angle of the blades according to wind speed, while yaw control controls the orientation of the nacelle to follow the wind direction so that the wind turbine can catch the wind efficiently.

[0052] In addition to these power transmission parts, rotating machinery, including those used for yaw and pitch control, requires forced circulation of lubricating oil. Lubricating oil reduces friction in the rotating parts of rotating machinery, preventing wear and damage to parts and energy loss. However, if the lubricating oil's lubricating performance deteriorates over time, or if it becomes contaminated by wear particles or dust, the coefficient of friction increases, increasing the risk of wind turbine failure.

[0053] When a wind turbine breaks down, significant loss costs occur, including the cost of replacing failed parts and reduced power generation revenue during power outages. Therefore, measures such as early parts procurement through remaining life prediction and early warning detection are desired, as well as shortening the duration of power outages. In particular, the gearbox, a critical component, is at increased risk of failure if the performance of the lubricant deteriorates, so technology to estimate the remaining life and replacement timing of the lubricant as early as possible is important.

[0054] <Lubricant remaining life evaluation method> One method for assessing the remaining life of lubricating oils, etc., is to filter a certain amount of lubricating oil through filter paper, dry the filter paper after filtration, and measure the weight of the residue remaining on the filter paper. This index is used as the degree of contamination (mass method). This explains a method for assessing the remaining life of gear oils that contain amine-based and phenol-based antioxidants, phosphorus-based extreme pressure agents, and have a synthetic PAO (polyalphaolefin) base oil. In this method, the same filter paper and a certain amount of lubricating oil are always used, and the same filtration method and filter paper drying method are used.

[0055] Figure 3 shows the results of measuring the contamination level (mass method) by sampling oil every year without changing the oil during the period from the same wind turbine, and shows the relationship between contamination level and time. The acceptable contamination level (mass method) for this wind turbine is 10 mg / 100 ml. Based on measurements up to the third year, it was predicted that the acceptable contamination level (mass method) would be reached after five years. The acceptable contamination level may vary depending on the type of oil, wind turbine, and machine. As mentioned earlier, contamination level has a positive correlation with the concentration of sludge and varnish precursors, so Figure 3 can be considered equivalent to the relationship between sludge and varnish production volume and time.

[0056] Here, the mechanism of sludge and varnish formation is directly correlated with the oxidation of the lubricating oil, that is, with the total acid number of the lubricating oil.

[0057] Figure 4 shows the change in the total acid number of the samples taken in Figure 3, showing the relationship between total acid number and time. The allowable total acid number is 0.25. Based on the measurements up to the third year, it was predicted that the allowable total acid number would be reached after five years. The allowable total acid number may differ depending on the type of oil, wind turbine, and machine.

[0058] However, methods such as collecting oil and filtering it with filter paper, or measuring the total acid number by titration, are difficult to apply to online monitoring. For this reason, for example, in offshore wind turbines, operation must be stopped to collect the lubricating oil, and workers must collect it. This means that frequent collection is not possible, and there is a risk that abnormalities in the lubricating oil, such as abnormal deterioration, may be overlooked.

[0059] On the other hand, lubricating oils are known to discolor due to deterioration such as the consumption of additives. When antioxidants are consumed, the oxidation of the base oil becomes more likely, causing the total acid number of the lubricating oil to increase. At the same time, the concentration of sludge and varnish precursors (level of contamination) increases, resulting in an increase in the level of contamination (mass method). For example, there are color-based diagnostic methods such as the ASTM color scale. There are also optical sensors that can output the color of lubricating oil as color coordinates such as RGB. A typical optical sensor can determine the color coordinates of the lubricating oil from light transmittance. By installing an optical sensor in a machine that uses lubricating oil, it is possible to continuously measure the color of the lubricating oil online.

[0060] As a result of the inventor's investigation, it was found that there is a correlation between the degree of contamination (mass method) and total acid number of the gear oil used and the color index of the gear oil used, which was determined optically.

[0061] Below, we will explain an example of estimating the remaining life of a lubricating oil using a calibration curve created using the changes in the lubricating oil over time determined from the contamination level (mass method) and total acid number, and color data obtained based on measurement data from an optical sensor.

[0062] Figure 5 is a graph showing the relationship between the degree of contamination of the lubricating oil (mass method) and the color of the lubricating oil measured with an optical sensor. In this case, the color coordinates of the sampled lubricating oil were measured using the color coordinates of colorless pentane as (255, 255, 255). The color of the lubricating oil determined with the optical sensor is displayed as the color difference (ΔE) calculated in a color space composed of a combination of RGB.

[0063] The definition of ΔE is, ΔE=(R 2 +G 2 +B 2 ) 1 / 2 R, G, and B refer to the three primary colors of light (Red, Green, and Blue) in additive mixing, and are expressed numerically as (R, G, B) in color coordinates. The wavelengths of the three primary colors of light are R: 610 to 750 nm, G: 500 to 560 nm, and B: 435 to 485 nm.

[0064] In addition, the difference between the maximum and minimum values ​​of R, G, and B is defined as MCD and is sometimes used for diagnosis. MCD=RB This is often the case.

[0065] RGB chromaticity encoded at 24bpp (24 bits per pixel) is represented by three 8-bit coded integers (0 to 255) that indicate the intensity of red, green, and blue. For example, (0, 0, 0) indicates black, (255, 255, 255) indicates white, (255, 0, 0) indicates red, (0, 255, 0) indicates green, and (0, 0, 255) indicates blue. In addition to the RGB color system, the XYZ color system and L * a * b * Color system, L * u * v * There are many different color systems, and these can be mathematically transformed into various color systems, so chromaticity can also be displayed in other color systems. If the color of the lubricant is quantified in chromaticity, the original lubricant color can be displayed on the monitor or display of a computer or monitoring system by converting the chromaticity value.

[0066] As shown in Figure 5, there was a high correlation between the contamination level (mass method) and ΔE for the lubricating oils (X, Y, Z) sampled periodically.

[0067] Figure 6 shows the correlation between the B value of the lubricating oil color coordinate (RGB) and the degree of contamination. Of the lubricating oil color coordinates (RGB), the B value changes the most over time, and as shown in Figure 6, the calibration curve obtained from the correlation between the degree of contamination (mass method) and the B value is also effective.

[0068] FIG. 7 is a calibration curve showing the correlation between the total acid number of the lubricating oil and ΔE determined by the optical sensor.

[0069] FIG. 8 is a calibration curve showing the correlation between the total acid number of the lubricating oil and the B value determined by the optical sensor.

[0070] Here, the relationship between the degree of contamination of the lubricating oil (mass method) C or the total acid number T of the lubricating oil and the color index of the lubricating oil (ΔE, B value, etc.) as shown in Figures 5 to 8 can be expressed as a function equation as follows: C=f(ΔE) …(1) or, C=f(B) …(2) T = f(ΔE) …(3) or, T = f(B) …(4) From equations (1) to (4), it can be seen that the following relationships hold: C=f(T) …(5)

[0071] The above C, T, B, and ΔE can be experimentally determined for specific lubricating oils. Calibration curves showing the relationship between the degree of contamination (mass method) and total acid number of a lubricating oil and the color coordinates can also be created using lubricating oils that have been subjected to forced oxidative degradation through various oxidation tests known as accelerated lubricating oil degradation tests. Even if the type and initial concentration of antioxidant are the same, the degree of color change due to degradation associated with use in a machine may vary if the type of base oil and the types and concentrations of other additives are different. For this reason, calibration curves showing the relationship between the degree of lubricating oil degradation and color must be created for each type of oil.

[0072] The color of lubricating oil changes due to oxidative degradation, but it also changes when large amounts of water, fine particles, wear debris, etc. are mixed into the oil. Here, oxidative degradation of lubricating oil is defined as "deterioration," and the phenomenon of water, fine particles, wear debris, etc. being mixed in from the outside is defined as "contamination." Regarding such degradation and contamination, for example, it is possible to diagnose whether a sample is only deteriorating or whether it is also deteriorating and has a certain level of contamination by looking at a graph of ΔE and MCD, which are indicators of lubricating oil color.

[0073] In lubricant diagnosis, if the above contamination occurs, the diagnosis result will be that the lubricant should be changed immediately and the machine inspected, because, for example, water contamination can cause corrosion and rust in the machine, and fine particles and wear powder can cause damage to gears and bearings.A lubricant remaining life assessment is carried out when there is no contamination or when the contamination is minor.

[0074] An optical sensor for measuring the properties of the lubricant is installed in parts that use lubricant, such as wind turbine gearboxes, and the remaining life of the lubricant can be calculated using the sensor data and a calibration curve previously obtained from the correlation between the degree of contamination of the lubricant (mass method) or the total acid number and the color of the lubricant.

[0075] In this way, an optical sensor installed in the gearbox lubricant detects the color of the lubricant, and based on this color information, the degree of lubricant deterioration and abnormal contamination can be determined in real time. Depending on the results of this determination, the system prompts the user to collect lubricant for detailed lubricant analysis at an appropriate time before the gearbox fails.

[0076] The relationship between the color information from the optical sensor and the degree of abnormality in the lubricant (impurity concentration, degree of oxidation, etc.), and the relationship between the color of the lubricant and the degree of contamination (mass method) and total acid number of the lubricant, are determined experimentally in advance and stored in a database. This makes it possible to prevent breakdowns by properly changing the lubricant, filters, or parts, and also enables efficient management of wind turbines by quickly carrying out repairs and other response procedures.

[0077] Hereinafter, the embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention should not be interpreted as being limited to the description of the embodiments shown below. Those skilled in the art will easily understand that the specific configuration can be changed within the scope of the idea or purpose of the present invention.

[0078] In the configuration of the invention described below, the same parts or parts having similar functions are denoted by the same reference numerals in different drawings, and duplicated explanations may be omitted.

[0079] When there are multiple elements with the same or similar functions, they may be described using the same reference numeral with different subscripts. However, when there is no need to distinguish between multiple elements, the subscripts may be omitted.

[0080] The designations "first," "second," "third," etc. in this specification are used to identify components and do not necessarily limit the number, order, or content of the components. Furthermore, numbers used to identify components are used in different contexts, and numbers used in one context do not necessarily indicate the same configuration in another context. Furthermore, this does not prevent a component identified by a certain number from also serving the function of a component identified by another number.

[0081] In order to facilitate understanding of the invention, the position, size, shape, range, etc. of each component shown in the drawings, etc. may not represent the actual position, size, shape, range, etc. Therefore, the present invention is not necessarily limited to the position, size, shape, range, etc. disclosed in the drawings, etc.

[0082] The following examples describe a wind turbine generator having a gearbox and a generator, and a wind turbine generator diagnostic system that collects information from the wind turbine generator and determines abnormalities in the wind turbine generator based on the collected information.When measuring and diagnosing the color of the lubricating oil supplied to the gearbox using a sensor, an example is described in which more accurate sensor diagnosis is performed by using the correlation between the color information and the degree of contamination (mass method) of the lubricating oil and the total acid number.

[0083] In the embodiment, in order to monitor the lubricating oil supplied to the mechanical drive unit of a wind turbine generator, various sensors, including an optical sensor installed in the lubricating oil of the gearbox, detect the acceleration of the gearbox to grasp the properties of the lubricating oil and the condition of the rotating machine, and based on the sensor information (a number indicating the physical and chemical state of the lubricating oil), the degree of abnormality of the lubricating oil and the condition of the rotating machine are determined in real time.

[0084] The system then prompts the wind turbine generator to collect lubricant oil for detailed lubricant analysis, change the lubricant oil, replace filters, and replace parts at the appropriate timing, before the gearbox fails, based on the results of the assessment. The system is equipped with an input device, a processing device, a storage device, and an output device. The storage device stores the correlation between the change in contamination level (mass method) and total acid number over time and the chromaticity data obtained from the optical sensor. The processing device, based on the optical sensor data that measures the chromaticity of the lubricant, estimates the time when the contamination level (mass method) or total acid number of the lubricant, determined from the chromaticity characteristics of the lubricant, will exceed a reference value.

[0085] Also, an embodiment is a wind power generator diagnostic system and method using an optical lubricant sensor, which uses a server equipped with a processing device, a storage device, an input device, and an output device. This method first performs the following steps to grasp the properties of the lubricant: a first step of acquiring color data of the lubricant in the wind power generator; a second step of measuring the contamination level (mass method) and total acid number of the sample; a third step of storing the measured contamination level (mass method) and total acid number in a chronological order in the storage device to generate additive concentration data; and a fourth step of estimating the time at which the contamination level (mass method) and total acid number will reach a predetermined threshold value by processing the contamination level (mass method) and total acid number data by the processing device.

[0086] (1. Overall system configuration) As an example of a machine for which lubricant diagnosis is performed, a schematic diagram of a lubricant monitoring system for a wind turbine generator with a lubricant supply system is shown in Figure 9. For the purpose of explanation, Figure 9 shows the nacelle 3 portion of the wind turbine generator 1 shown in Figure 2. Inside the nacelle 3 are a main shaft 31, a gearbox 33, a generator 34, and bearings such as yaw and pitch bearings (not shown), all of which are supplied with lubricant from a lubricant tank 37.

[0087] As shown in FIG. 9 , multiple wind turbines 1 are usually installed on the same site, and these are collectively referred to as farm 200a, etc. Each wind turbine 1 is equipped with various sensors (not shown) in its lubricating oil supply system, and sensor signals reflecting the state of the lubricating oil are aggregated in a server 210 in the nacelle 3. In addition, the sensor signals obtained from the server 210 of each wind turbine 1 are sent to an aggregation server 220 arranged for each farm. Data from the aggregation server 220 is sent to a central server 240 via a network 230. Data from other farms 200b and 200c is also sent to the central server 240. In addition, the central server 240 can send instructions to each wind turbine 1 via the aggregation server 220 and the server 210.

[0088] (2. Sensor placement) 10 is a conceptual diagram of a rotating machine equipped with a lubricant sensor. Lubricant is supplied to a rotating machine 302 from a lubricant supply device 301 such as a pump. The lubricant supply device 301 is connected to a lubricant tank 37 and receives the supply of lubricant. The rotating machine 302 may include, for example, a gearbox 33 and other parts where mechanical contact occurs, as well as a power transmission unit for performing yaw and pitch control.

[0089] The sensor group 304 is arranged in the lubricant flow path or the like to detect the state of the lubricant. In Example 1, the measurement unit 303 is provided in a flow path (branch line) branching off from the lubricant flow path connected to the lubricant drain port of the rotating machine 302, and a portion of the lubricant is introduced into this measurement unit 303, and the sensor group 304 is installed in the measurement unit 303. The branch line is preferably provided near the end of the lubricant path to monitor the deterioration state of the lubricant. The measurement unit 303 is not provided in the main lubricant flow path (circulation line) because the flow rate of the lubricant in the measurement unit 303 can be adjusted to a flow rate suitable for detecting the state of the lubricant. In this way, the hydraulic pressure can also be adjusted by using a branch line branching off from the circulation line and arranged in parallel with the circulation line, and adjusting the bending shape and thickness of the branch line.

[0090] The lubricating oil discharged from the rotary machine 302 returns to the lubricating oil tank 37 via the oil filter 305. The mesh diameter of the oil filter 305 is 5 to 50 μm.

[0091] The terms "upstream" and "downstream" are sometimes used to describe the positional relationship along the lubricating oil flow path. The lubricating oil moves relatively from upstream to downstream. In the case of FIG. 10, the lubricating oil supply device 301 is located upstream, the oil filter 305 is located downstream, and the measuring unit 303 is located between them. Note that the arrangement of each element is not limited to the configuration of FIG. 10; for example, as described below, the lubricating oil tank 37 may be located between the rotating machine 302 and the measuring unit 303.

[0092] The sensor group 304 measures various parameters of the lubricating oil. For example, physical quantities include temperature, oil pressure, and the like, in addition to color measured by an optical sensor. Instead of or in addition to the optical sensor, a sensor may be provided that measures electrical properties of the lubricating oil, such as permittivity and conductivity. Temperature, oil pressure, and the like can be measured using known sensors. The state of the lubricating oil can be evaluated based on the temporal changes in these parameters. These temperature and other sensors are not essential, but it is preferable to provide them in order to detect the state of the lubricating oil in more detail.

[0093] In the embodiment, the sensor group 304 includes an optical sensor equipped with a visible light source and a light receiving element. The optical sensor measures the visible light transmittance of the lubricating oil and outputs chromaticity information (R, G, B values) of the lubricating oil. From the acquired chromaticity data, the amount of remaining additives in the lubricating oil is calculated, and a deterioration diagnosis and remaining life diagnosis are performed. In the diagnosis using sensor data, a diagnosis is performed based on sensor data from the optical sensor or on data from the optical sensor and one or more other types of sensors.

[0094] As lubricating oil is used, its antioxidants are consumed, causing its quality to deteriorate and it no longer performs its original function. For this reason, maintenance such as replacement must be performed depending on the degree of quality deterioration. In order to know the timing of such maintenance, it is useful for the efficiency of maintenance management to be able to monitor data that can be collected by the sensor group 304 from a remote location. The data collected by the sensor group 304 is collected, for example, in the server 210 in the nacelle 3, and then sent via the aggregation server 220 that aggregates data within the farm 200 to the central server 240 that aggregates data from multiple farms.

[0095] Furthermore, the data to be aggregated may include not only data related to the lubricant but also data indicating the operating status of the wind turbine. For example, the data may include an acceleration sensor that detects vibrations of the wind turbine 1 (the larger the value, the faster the rate of lubricant deterioration), wind turbine output value (the larger the value, the faster the rate of lubricant deterioration), actual operating time (the longer the value, the faster the rate of lubricant deterioration), machine temperature (the higher the value, the faster the rate of lubricant deterioration), shaft rotation speed (the faster the rate of lubricant deterioration), and lubricant temperature (the higher the value, the faster the rate of lubricant deterioration). These data can be collected from sensors of known configurations installed at various locations on the wind turbine or from control signals from the device.

[0096] (3. Lubricant diagnosis flow) Figure 11 is a flow diagram showing the lubricant oil diagnosis process according to the embodiment. The process shown in Figure 11 is performed under the control of either the server 210, the aggregation server 220, or the central server 240 in Figure 9. In the following example, it is assumed that the process is performed by the central server 240. Functions such as calculation and control are realized by software stored in the server's storage device being executed by a processor, and the specified processes are realized in cooperation with other hardware. Note that functions equivalent to those configured by software can also be realized by hardware such as an FPGA (Field Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit).

[0097] When the central server 240 performs control, it has multiple wind power generators 1 under its control, so the following processing is performed for each wind power generator. This processing is basically a repetitive process, and the start timing is set by a timer or the like; for example, the processing starts at midnight every day (S601). The central server 240 can also perform the processing at any timing in response to instructions from an operator.

[0098] In step S602, the central server 240 checks when the lubricant needs to be replaced. The initial value for the replacement time is set, for example, as an initial value for the remaining life, assuming that the lubricant is operating at its design temperature. This replacement time can be updated later in step S610 based on actual measurement data.

[0099] If it is time to change the lubricant, the lubricant is changed in step S603. Since changing the lubricant is usually done by a worker, the central server 240 displays and notifies the worker when and what to change.

[0100] If it is not time to change the lubricant, in step S604, the central server 240 diagnoses the properties of the lubricant based on sensor data. Sensor data can include lubricant color information obtained by an optical sensor, as well as temperature, oil pressure, and particle concentration in the lubricant. The data measured by the sensor group 304 is sent to the central server 240, which evaluates the properties of the lubricant by, for example, comparing the parameters obtained from the sensors with predetermined reference values. The central server pre-stores the correlation between color and contamination level (mass method), the correlation between color and total acid number, the changes in R, G, and B values ​​when antioxidants in the lubricant are consumed (the additives decompose to generate oxidation products), and the changes in R, G, and B values ​​when wear particles are generated in the lubricant, as shown in Figures 3 to 8, and uses these data for comparison with the sensor data. These reference values ​​can be predetermined thresholds or the amount of change in sensor information per predetermined unit time.

[0101] Fig. 12 shows the configuration of programs and data stored in the central server 240. Like a general server, the central server 240 comprises an input device 1001, an output device 1002, a processing device 1003, and a storage device 1004. Fig. 12 shows the configuration of programs and data stored in the storage device 1004.

[0102] The storage device 1004 of the central server 240 stores the following data: a correlation database (DB) 241 that stores experimentally determined correlations between the color (ΔE and B) shown in Figures 7 and 8 and the total acid number determined by indicator titration or potentiometric titration; a DB 242 that stores the total acid number of the lubricating oil of an actual machine (e.g., a wind turbine) measured by indicator titration or potentiometric titration; and a DB 243 that stores chronological sensor data acquired by an optical sensor. The correlation DB 241 may store the correlation data shown in Figures 5 and 6, which show the correlation between contamination level and color, instead of or in addition to the data shown in Figures 7 and 8. By referencing the correlation DB 241, it is possible to convert between total acid number, color, and contamination level (sludge and varnish production amount).

[0103] The correlation DB 241 may store, for example, the functions shown in Equation (3) or Equation (4), or the data shown in Figures 7 and 8. The data conversion program 244 can use the information stored in the correlation DB 241 to convert the data in the chromaticity DB 243 into the total acid number of the lubricating oil measured by indicator titration or potentiometric titration. The data in the total acid number DB 242 stores, for example, the data shown in Figure 4.

[0104] If the data in the color DB243 and the total acid number DB242 are time series data relating to the same measurement object, the converted data 245 obtained by the data conversion program 244 is continuous with the data in the total acid number DB242, and therefore the two different measurement methods can be used as a continuous series of time series data.

[0105] The storage device 1004 also includes a diagnostic program 246 that controls the entire lubricant diagnostic process shown in FIG.

[0106] Returning to Fig. 11, if the diagnosis results in steps S605 and S606 are abnormal, the lubricating oil is changed in step S603. Specifically, the lubricating oil change is performed by notifying the person in charge of managing the lubricating oil change that a change is necessary. If no abnormality is found, step S609 is performed.

[0107] In process S605, for example, if all the R, G, and B values ​​of the optical sensor are lower than predetermined thresholds, it is determined that there is a contamination abnormality. Such a determination detects blackening of the lubricating oil. However, data from a conventional sensor may also be used to determine contamination abnormalities.

[0108] In S606, the chromaticity data is converted into an estimated value of the total acid number of the lubricating oil containing the additives used in the machine, for example, using the correlation between the total acid number and chromaticity shown in Figures 7 and 8. If the total acid number obtained from the chromaticity measured by the optical sensor exceeds a predetermined threshold, it is determined that there is an abnormality in the degree of additive degradation. It is also possible to determine that there is an abnormality in the degree of additive degradation when the chromaticity is lower than a predetermined threshold, without obtaining the total acid number from the chromaticity.

[0109] In process S609, the chromaticity measurement data and the like are input to the central server 240, and the chromaticity measurement data is saved in chronological order in the chromaticity DB 243.

[0110] From the perspective of preventive and planned maintenance of wind turbines, it is desirable to perform predictive diagnosis of lubricant deterioration based on the transition of the total acid number of the lubricant before it is determined that there is an abnormality.

[0111] As described above, the total acid number of lubricating oil measured by indicator titration or potentiometric titration and the color information of the lubricating oil measured by an optical sensor can be used to obtain time-series data on the normality of the lubricating oil. Knowing the remaining lifespan of the lubricating oil allows for early detection of the lubricating oil's lifespan. Therefore, by performing maintenance such as appropriate lubricating oil changes, it is possible to prevent abnormalities in wind turbine generators. It is also possible to optimize the lubricating oil change cycle. Furthermore, antioxidant concentration can be measured using a simple method, and by installing an optical sensor inside the nacelle, it is possible to remotely monitor the increase in the total acid number of the lubricating oil online.

[0112] (4. Lubricant remaining life assessment) In this embodiment, in the replacement timing estimation and update process S610 in Figure 11, the total acid number of the lubricating oil used in the wind turbine is determined by indicator titration or potentiometric titration, and the individual color coordinates of the same lubricating oil sample are determined by an optical sensor.Based on the information obtained from the correlation between the total acid number and the color coordinates, the total acid number is determined from the color measurement of the lubricating oil, and the remaining life of the lubricating oil is also calculated.

[0113] For lubricating oils of the same model number, we obtained new oil (A), as well as samples that had been used in a wind turbine for one year (B), two years (C), and three years (D). For these lubricating oil samples (A) to (D), the tendency of the total acid number to increase over time was confirmed by potentiometric titration, as shown in FIG.

[0114] As shown in Figure 13, the threshold for the total acid number of this lubricant is set to 0.3 mg KOH / g. By calculating the correlation function between the total acid number and the contamination level (mass method), which is an indicator of the amount of sludge and varnish generated, it is possible to predict the generation of sludge and varnish from the color coordinates of the lubricant. When the total acid number of this lubricant reaches 0.3, the contamination level becomes 10 mg / 100 ml. In other words, the lifespan of this lubricant is the period from the start of use until the total acid number reaches the threshold. By setting a threshold for the contamination level (mass method), the lifespan of this lubricant is the period from the start of use until the contamination level (mass method) reaches the threshold. If the thresholds for the total acid number and the contamination level (mass method) are reached at different times, the lifespan of this lubricant is the period until either one reaches the threshold. In this way, a threshold for the total acid number can be set to control the amount of sludge and varnish generated, and the total acid number can be indirectly calculated from the color.

[0115] Meanwhile, color measurements were performed on samples (A) to (D) using, for example, the optical sensor disclosed in Patent Document 3. At this time, the color coordinates of new oil (A) were normalized to (255, 255, 255). The ΔE value was calculated from each color coordinate. Regarding the color coordinate normalization method, evaluation was possible even when the color coordinates of colorless liquids, such as additive-free base oils and colorless solvents, were set to (255, 255, 255).

[0116] 14 is a graph showing the relationship between the ΔE value and the total acid number, based on the correlation function (for example, the relationship of Equation (3)) between the total acid number quantitative determination result (first result) obtained by potentiometric titration and the lubricating oil diagnostic result (second result) previously obtained by optical measurement. The relationship between the total acid number and the ΔE value, as shown in FIG. 14, was clarified.

[0117] From Figure 14, it was found that when the total acid number was 0.3, the ΔE value was 200. In other words, based on the information showing the relationship between the first and second results, it was possible to set a ΔE threshold value for controlling the total acid number value. Because there is a correlation between the total acid number and the amount of sludge and varnish produced, this means that a color threshold value was set to control the amount of sludge and varnish produced.

[0118] In this way, it was found that if Figure 14 is used as a calibration curve, the total acid number determined by potentiometric titration can be obtained from the color coordinates of the lubricating oil measured by an optical sensor. The correlation DB 241 in Figure 12 stores, for example, the calibration curve shown in Figure 14.

[0119] In this way, by using the correlation DB241, in process S610, it is possible to use the correlation DB241 to make compatible the data based on the total acid number quantification results (first results) obtained in advance by potentiometric titration and the data based on the lubricating oil diagnosis results (second results) obtained in advance by optical measurement.

[0120] FIG. 15 is a graph showing the relationship between total acid number and time to explain the principle of remaining life assessment in the embodiment. In this embodiment, the total acid number of sampled lubricating oil samples was measured using potentiometric titration during the period 1501 from when new oil was used in a wind turbine until two years had passed, and data 1502 was obtained. From the second to fourth years, the color of the lubricating oil was measured using an optical sensor, and the color information was converted using the data conversion program 244 and the correlation DB 241, thereby obtaining the total acid number 1503 in near real time. As shown in FIG. 15, from the data 1502 and the total acid number 1503, using well-known techniques such as function approximation and extrapolation, it is possible to predict that the remaining life 1504, until the total acid number exceeds 0.3 at the four-year point, is 0.5 years.

[0121] The remaining life thus determined is shown to the user, for example, on a display in step S611. In step S612, the optical sensor output may be converted into a color corresponding to the color information of the lubricating oil and displayed.

[0122] In Figure 15, color information data based on an optical sensor is converted into total acid number based on potentiometric titration. Conversely, the total acid number based on potentiometric titration can also be converted into color information data based on an optical sensor using the calibration curves in Figures 7 and 8.

[0123] In Figure 16, the contamination level (mass method) is measured in a wind turbine from the time new oil was used until two years have passed 1501, and the contamination level (mass method) is converted to ΔE to obtain data 1602. From the second to fourth year, the color of the lubricating oil is measured using an optical sensor, and ΔE data 1603 can be obtained in near real time.

[0124] As described above, in this embodiment, the total acid number data and contamination level (mass method) data based on potentiometric titration can be converted into data based on color information obtained by optical measurement, and the data can be converted into data based on color information obtained by optical measurement. This makes it possible to monitor the properties of lubricating oil based on the same standards over a longer period of time. Therefore, more accurate remaining life assessment is possible based on data showing changes in lubricating oil properties over time.

[0125] FIG. 17 is a block diagram showing an embodiment of a gas turbine, which is an example of monitoring turbine oil.

[0126] The turbine 700 is connected by a turbine shaft 701. Turbine oil is stored in a main oil tank 702, sent to an oil cooler 703 by an oil pump 712, and then supplied to the turbine shaft 701. The turbine oil is supplied in the direction of arrow 714, and then returns to the main oil tank 702 through a return flow path 705.

[0127] In this embodiment, an optical sensor 704 for monitoring changes in the properties of the turbine oil was installed between the oil cooler 703 and the turbine shaft 701, and acquired color information of the lubricating oil.

[0128] As explained in equations (1) to (5), by utilizing the correlation between the total acid number, the amount of sludge and varnish produced, and the color information, it is possible to set a threshold value for the total acid number for controlling the amount of sludge and varnish produced in an attached storage device and compare it with the total acid number calculated indirectly from the color information of optical sensor 704. To do this, optical sensor 704 should be provided with a means for converting data between color information and total acid number. Alternatively, it is also possible to set a threshold value for color information for controlling the amount of sludge and varnish produced in an attached storage device and compare it directly with the color information.

[0129] Figure 18 is a graph showing the results of a preliminary calculation of the correlation between the total acid number and color coordinate (ΔE) of turbine oil. The reference value for the total acid number of this turbine oil is 0.2 (mg KOH / g), and the ΔE value when the total acid number was 0.2 was 240. Similarly, for turbine oil, the results of a preliminary calculation of the correlation between the total acid number of turbine oil and color coordinate (B) can be obtained, as in Figure 8.

[0130] Figure 19 shows the results of continuous measurement of oil color using the optical sensor 704 in the gas turbine shown in Figure 17. The value 2051 after two years of use is plotted. The ΔE value from the start of use until two years have passed was extrapolated, and the time when the total acid number would reach 0.2 was predicted to be 3.8 years after use. Similarly, when the B value of the color coordinate was used, it was also possible to determine that the total acid number would reach 0.2 after 3.8 years.

[0131] Figure 20 shows a configuration in which a branch flow path is provided in the oil flow path of a gas turbine and an optical sensor 704 is installed, and the difference from Figure 17 is the placement of the optical sensor 704. With this configuration, it was also possible to monitor the increase in total acid number due to oil use.

[0132] As explained in the above examples, the configuration of the examples makes it possible to easily determine the generation of sludge and varnish in oil by indirectly determining it via the total acid number.

[0133] Figure 21 is a conceptual diagram showing the relationship between viscosity, total acid number, antioxidant concentration, and sludge / varnish amount; these correlations can be used to estimate the values ​​of each other. When the antioxidant concentration decreases, oxidation is promoted, total oxidation increases, sludge / varnish is produced, and viscosity increases. A threshold value 2101 is set for the amount of sludge / varnish before the viscosity starts to increase, urging the user to change the oil. This timing can be detected by indirectly measuring the total acid number from the color of the oil.

[0134] In the above-described embodiment, wind turbines and gas turbines were used as examples of rotating machines, but this embodiment can also be applied to diagnosing the deterioration of additives in lubricating oils of rotating machines such as steam turbines, nuclear generators, thermal power generators, geared motors, railway vehicle wheel flanges, air compressors, transformers, movable plant machinery, and large pump machinery.

[0135] Furthermore, the remaining life diagnosis of lubricating oil according to this embodiment can be applied to remote monitoring by installing an optical sensor in the lubricating oil inside the machine, or it is also possible to collect lubricating oil and measure it with an optical sensor outside the machine or in a laboratory. Furthermore, the optical sensor can be replaced by a device that can measure the color coordinates of the lubricating oil. [Explanation of symbols]

[0136] Central server 240, input device 1001, output device 1002, processing device 1003, storage device 1004, correlation database DB241, antioxidant concentration DB242, chromaticity DB243, data conversion program 244, conversion data 245, diagnostic program

Claims

1. A diagnostic method for lubricating oil containing an additive used in a machine, comprising: The first result is a result of measuring the total acid number of the lubricating oil obtained separately in advance, The second result is the result of measuring the amount of sludge and varnish generated by the lubricating oil, which was obtained separately in advance. A third result, which is a result of optical measurement of the lubricating oil obtained separately in advance; Based on Information indicating a relationship between the first result and the second result; Information indicating a relationship between the first result and the third result; and information indicating a relationship between the second result and the third result; Based on the above information, First data based on the results of a total acid number measurement of a lubricating oil containing an additive used in the machine; Second data based on the results of measuring the amount of sludge and varnish generated by lubricating oil containing the additive used in the machine; and third data based on a result of optical measurement of a lubricating oil containing an additive used in the machine, and converting the third data into an estimate of the total acid number of the lubricant, including the additives, used in the machine using information indicating a relationship between the first result and the third result.

2. The optical measurement includes: It is characterized by an optical measurement that determines the color coordinate of the lubricating oil from the light transmittance of the lubricating oil. The method for diagnosing a lubricating oil according to claim 1.

3. As the third result, The lubricant color coordinate B value or ΔE value is used. The method for diagnosing a lubricating oil according to claim 1.

4. The measurement of the amount of sludge and varnish generated in the lubricating oil is performed by a contamination measurement method. The method for diagnosing a lubricating oil according to claim 1.

5. A method for diagnosing a lubricating oil containing an additive used in a machine, comprising: The first result is a result of measuring the total acid number of the lubricating oil obtained separately in advance, The second result is the result of measuring the amount of sludge and varnish generated by the lubricating oil, which was obtained separately in advance. A third result, which is a result of optical measurement of the lubricating oil obtained separately in advance; Based on Information indicating a relationship between the first result and the second result; Information indicating a relationship between the first result and the third result; and information indicating a relationship between the second result and the third result; Based on the above information, First data based on the results of a total acid number measurement of a lubricating oil containing an additive used in the machine; Second data based on the results of measuring the amount of sludge and varnish generated by lubricating oil containing the additive used in the machine; and third data based on a result of optical measurement of a lubricating oil containing an additive used in the machine, The method is characterized in that at least one of the following is performed: setting a first threshold value, which is a threshold value of the total acid number for controlling the amount of sludge / varnish generated, based on information showing the relationship between the first result and the second result; and setting a second threshold value, which is a threshold value of the optical measurement result for controlling the amount of sludge / varnish generated, based on information showing the relationship between the first result and the second result and information showing the relationship between the first result and the third result. Lubricant diagnostic methods.

6. Converting the third data into an estimate of the total acid number of a lubricating oil, including additives, used in the machine using information indicating a relationship between the first result and the third result; comparing the estimated value to the first threshold and performing at least one of an indication and a notification based on the comparison result; The method for diagnosing a lubricating oil according to claim 5.

7. Comparing the third data with the second threshold value, and performing at least one of displaying and notifying based on a comparison result. The method for diagnosing a lubricating oil according to claim 5.

8. A diagnostic device for lubricating oil containing an additive used in a machine, comprising: A storage device for storing at least one of the first threshold value and the second threshold value according to claim 5, a sensor for acquiring third data based on the results of an optical measurement of a lubricating oil containing an additive used in the machine; The third data is directly or after being converted, and compared with at least one of the first threshold value and the second threshold value, and display or notify is performed based on the comparison result. Lubricant diagnostic equipment.

9. A diagnostic device for lubricating oil containing an additive used in a machine, comprising: a correlation database that records information indicating a relationship between a first result, which is a result of a total acid number measurement of a lubricating oil obtained separately in advance, and a third result, which is a result of an optical measurement obtained separately in advance, based on the first result and the third result; A data conversion unit that performs conversion between first data based on the result of a total acid number measurement of the lubricating oil containing the additive used in the machine and third data based on the result of optical measurement of the lubricating oil containing the additive used in the machine based on the information; Having The third data is converted into an estimate of the total acid number of the lubricating oil including the additive used in the machine using information indicating the relationship between the first result and the third result. Lubricant diagnostic equipment.

10. The optical measurement comprises: It is characterized by an optical measurement that determines the color coordinate of the lubricating oil from the light transmittance of the lubricating oil. The lubricant diagnostic device according to claim 9.

11. As the third result, The lubricant color coordinate B value or ΔE value is used. The lubricant diagnostic device according to claim 9.

12. A diagnostic system for lubricating oil containing an additive used in a machine, comprising: An optical sensor for acquiring color information of the lubricant; A first database storing the total acid number of the lubricating oil; A data conversion unit that derives the total acid number from the color information; a correlation database to which the data conversion unit refers, The correlation database includes: The information includes information indicating a relationship between a first result, which is a previously obtained total acid number quantitative result, and a third result, which is a color information of the lubricating oil previously obtained by optical measurement; converting the color information of the lubricant obtained by the optical sensor into an estimated total acid number of the lubricant including the additive used in the machine using information indicating a relationship between the first result and the third result; Lubricant diagnostic system.

13. The optical sensor comprises: It is characterized by being an optical sensor that determines the color coordinates of lubricants used in machinery by light transmitted through the lubricants. The lubricant diagnostic system according to claim 12.

14. As the third result, Characterized by using the color coordinate B value or ΔE value of the lubricating oil. The lubricant diagnostic system according to claim 12.

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