JPS63103961A - Method and device for inspecting deterioration of lubricating oil - Google Patents

Abstract

PURPOSE:To easily and accurately detect the deterioration of lubricating oil by providing electrodes of both ends, i.e. the entrance and exit of a capillary tube, making the lubricating oil to flow in the capillary tube, and measuring the fluid potential between electrodes. CONSTITUTION:The electrodes 102 and 104 are provided to both ends, i.e. the entrance and exit o the capillary tube 100. The lubricating oil which is a sample to be inspected is made to flow in the capillary tube 100. At this time, ions or charged particles in the lubricating oil are attracted to the internal wall of the capillary tube 100 to form an electric double layer 106a, and charges are dislocated in the fluid in the capillary tube 100. When the lubricating oil deteriorates more, a polar material such as carboxylic acid is produced and attracted to the internal wall to increase variation in the zeta potential of the electric double layer. For the purpose, the potential difference between the electrodes 102 and 104 is detected by a potentiometer 10 to detect the deterioration of the lubricating oil. Thus, the fluid potential between the two electrodes is measured, so the degree of the deterioration of the lubricating oil is easily and accurately known.

Description

Detailed Description of the Invention -E-1 The present invention relates to an inspection method and device for inspecting deterioration of lubricating oil, and in particular to lubricating oil used in movable equipment such as ships and vehicles. The present invention relates to a simple lubricating oil deterioration testing method and device that can be used to test lubricating oil at any desired location.

′ to j, for example, a ship,
Many movable members are used in vehicles and other various machines, and lubricating oil is used to smooth the pressure movement of such movable members and also to achieve a cooling effect. In machinery that uses lubricating oil, the properties of the lubricating oil greatly affect the stable operation of the machine, and the lubricating oil usually needs to be replaced frequently.

Recently, there has been a call for maintenance-free and energy saving in various fields, and even for machinery that uses lubricants, there is a demand for long-life lubricants with stable properties over a long period of time, and there is a need for appropriate lubricant oils. There is a need for a method and device that can more accurately and easily determine the replacement time.

To determine when to change the lubricant, use f[! ! 1ffl
It is necessary to know the degree of deterioration of oil. Conventionally, deterioration of lubricating oil was measured by periodically sampling lubricating oil from machinery and measuring the viscosity, neutralization value, insoluble content, etc. based on specified test methods. A method is used to understand the state of deterioration.

°However, such a method is complicated and takes a lot of time, and it is impossible to quickly summarize the results. In particular, it has been more difficult to implement the above method for machinery that is often not fixed at a fixed location, such as ships and vehicles.

In addition, as a lubricating oil deterioration inspection method (and device), a method of measuring the electrical conductivity and dielectric constant of oil (Japanese Patent Application Laid-Open No. 58-8531
No. 4, JP-A-58-128411J+, etc.)
method for calculating the degree of deterioration from oil temperature, engine speed, and load (JP-A-59-43299, JP-A-61-65)
Please refer to No. 007, JP-A No. 61-65008, etc.)
is proposed. However, in the former case, the electrical conductivity and dielectric constant of the oil vary greatly depending on the oil usage conditions or additive components in the oil, and in the latter case, because the properties of the oil are not directly measured. There is a problem in that it is not always possible to accurately determine the deterioration in the practical performance of lubricating oil.

The inventors of the present invention conducted many research experiments to solve this problem, and found that the flowing voltage generated when lubricating oil flows changes as the lubricating oil deteriorates.

The present invention is based on this new knowledge.

1 to 11 An object of the present invention is to provide a lubricating oil deterioration testing method and apparatus that can easily and accurately detect and measure the degree of deterioration of lubricating oil.

Another object of the present invention is to provide a simple and accurate lubricating oil deterioration testing method and apparatus particularly suitable for measuring the degree of deterioration of lubricating oil in movable machines such as ships and vehicles.

1. The above-mentioned problems are achieved by the lubricating oil deterioration testing method and device according to the present invention. In summary, the present invention allows the lubricating oil to be inspected to flow through two electrodes placed apart from each other, and measures the flowing potential generated between the two electrodes to detect the deterioration of the lubricating oil. This is a lubricating oil deterioration testing method characterized by testing the degree of deterioration of lubricating oil.

In this inspection method, a filler is filled inside and a part to be inspected is used.
11 A column that allows the flow of lubricating oil, electrodes disposed at the inlet and outlet portions of the column, and a potentiometer connected to the electrode to measure the flow potential of the lubricating oil flowing through the column. This can be suitably carried out using a lubricating oil deterioration inspection device J that is equipped with means for supplying lubricating oil to the column, and preferably a pressure gauge that measures the pressure of the lubricating oil in the column.

Next, the lubricating oil deterioration measuring method and apparatus according to the present invention will be explained in more detail based on one embodiment.

First, the principle of the lubricating oil deterioration inspection method according to the present invention will be explained with reference to FIGS. 1 to 3. capillary tube 100
It has been found that when a liquid containing ions or charged particles is caused to flow through a porous phase (or a porous phase), a potential difference is generated between electrodes 102 and 104 formed at both ends of the inlet and outlet of the capillary tube 100. To explain further, as shown in FIG. 2A, when a liquid containing ions and charged particles is caused to flow through the capillary tube 100, ions or other particles are present at the contact surface between the inner wall surface of the capillary tube 100 and the liquid, that is, at the solid-liquid interface. An electric double layer 106 is formed by adsorption of charged particles, and the potential state at that time is shown in FIG. 2B. As understood from FIG. 2B, the inner wall surface of the capillary tube 100 has a predetermined negative potential, and as it approaches the center of the capillary tube, the potential decreases to zero potential. When a liquid is allowed to flow under such conditions, some of the charges in the double layer are carried along with the liquid, resulting in uneven distribution of charges in the capillary and a potential difference between the entrance and exit of the capillary. Become.

The potential difference (flowing potential) E is the pressure difference Δ that causes the liquid to flow.
Proportional to P, ΔP (1) holds for E=,
The proportionality constant is expressed by the following formula.

K=(εζ)/(4πη included) (2) Here, ε: Liquid rrL rate ζ: Zeta potential (slip surface 1 of liquid in electric double layer)
(potential at 06a) η: viscosity coefficient of the liquid; electrical conductivity of the liquid As is clear from equation (2), the proportionality constant is determined by the viscosity, permittivity, conductivity, and zeta potential of the liquid.

In the process of studying the above equation (2), the present inventors found that, for example, when the liquid is lubricating oil, if the I11 lubricating oil deteriorates, the proportionality constant K changes significantly, and in particular, the zeta potential We found that this changes depending on the adsorption of ions to. Furthermore, it has been found that the absolute value of the zeta potential changes depending on the way the ions are adsorbed, and the sign of the potential, that is, the direction of the slope, also changes, as shown in FIG. For example, a type of surfactant called a detergent and dispersant is added to engine oil (11!I lubricating oil), but in the case of new oil, this surfactant is selected on the inner wall surface of the capillary tube, that is, the solid phase. It is naturally adsorbed, and as the oil deteriorates, polar substances like carvone are generated.

It was found that the zeta potential changes as the adsorption state of the surfactant to the solid phase changes.

The present inventors have discovered that since the change in the zeta potential appears as a change in the streaming potential, the degree of deterioration of the lubricating oil can be measured by detecting the streaming potential. In other words, the present invention allows the lubricating oil to be inspected to flow through two electrodes placed apart from each other, and measures the flowing potential generated between the two electrodes to detect deterioration of the lubricating oil. This is a lubricating oil deterioration testing method characterized by testing the degree of deterioration.

Next, an embodiment of an apparatus that can suitably implement the lubricating oil deterioration inspection method according to the present invention as described above will be described with reference to FIG.

The lubricating oil deterioration testing device 1 according to the present invention has a column 2 in which a filler 4 is housed, and electrodes 6.8 at the inlet and outlet of the column 2, respectively. will be placed. Column 2 is made of glass, ceramics, such as Teflon (
It is made of synthetic resin such as DuPont (trade name)':4, bisque, paper, metal, etc. The column 2 only needs to be particularly pressure-resistant, and its size and shape are not limited to a specific one, but in this example, it has a diameter of 15 m, for example.
The column is made of cylindrical glass and is filled with a filler 4 having a diameter of 5 pm, such as glass beads, so as to have a thickness of 5 mm. The filler is made of the same material as the column 4, and spherical or cylindrical fillers such as ceramics, synthetic resins, unglazed ceramics, paper, and metals are also preferably used. Also, the filler.

Since a larger contact area with the lubricating oil supplied into the column is preferable for potential difference detection, a smaller particle size is preferable. .8 is a platinum electrode in the form of a mesh, and is connected to a potentiometer 10.

A pressure sensor 12.14 is arranged adjacent to the inlet and outlet electrodes of the column 2 to measure the pressure within the column, the signal of which is transmitted to a differential pressure transducer 16.

With the above configuration, the lubricating oil to be measured is supplied from the storage tank 20 to the column 2 by the pump 22. At this time, it is preferable that foreign substances contained in the lubricating oil supplied from the pump 22 to the column 2 be filtered out by a filter 24.The lubricating oil supplied to the column 2 passes through the filler portion 4 in the column. In between, a flowing potential is generated between both electrodes 6.8, and its magnitude and sign are measured with a potentiometer IO. The inspected lubricating oil that has passed through column 2 is collected into reservoir 26 . Furthermore, when the lubricating oil passes through the column, the pressure within the column (that is, the flow rate of the lubricating oil passing through the column) is measured at the same time by the differential pressure transducer 16. The signal from is transmitted to the arithmetic processing section 18. The arithmetic processing section 18 processes each signal according to a predetermined program, and then displays the measurement results to the operator on a display device 19, such as an X-Y plotter.

The operator can learn the degree of deterioration of the lubricating oil by examining the graphs etc. displayed on the x-y plotter. Of course, it is also possible to automatically display the degree of deterioration using a numerical value or the like.

The degree of deterioration of test oils A, B, and C was examined using the measuring device 1 described above. The test results displayed on the xY plotter are illustrated in FIG.

Test oil A is a new lubricating oil, and its component composition is 3
2 Neutral oil contains Zn dialkyl dithiophosphate (antioxidant IF and anti-wear agent), calcium sulfonate (cleaning dispersant), and succinimide (ashless clearing dispersant) at a total of 7.6 Wt0%. This is what I did.

Test oil B was prepared by adding degraded oil (1 part) to 100 parts of test oil A above.
50 neutral oil in ISO oxidation stability tester.
20 parts of the mixture was mixed with 20 parts of the product aged at 5.5°C for 48 hours, and a small amount of white kerosene was added to adjust the viscosity.

Test oil C was a mixture of 100 parts of the above test oil A and 1 part of degraded oil.
50 neutral oil in ISO oxidation stability tester.
A mixture of 30 parts of 100% (degraded at 5.5°C for 56 hours) and a small amount of white kerosene was added to adjust the viscosity.

Table 1 shows the properties of test oils A, B, and C.

Table 1 Properties of test oils From FIG. 5, the proportionality constant K (flowing potential/pressure) of test oils A, B, and C was determined by calculation. The results were as follows.

Test oil A -1,4mV/gecm' Test oil B
Test +0.73 mV/g-crn'Test oil test +0.95 mV/gacrn'' From the above results, the following conclusions can be drawn: (1) As the pressure increases, the streaming potential changes approximately linearly. do.

(2) While the proportionality constant K is negative in new oil (test oil A), it changes positively in deteriorated oils (test oils B and C). This means that the zeta potential of the new oil was negative, but it changed to positive due to deterioration.

(3) Furthermore, since the proportionality constant K changes depending on the degree of deterioration, the degree of deterioration of the lubricating oil can be detected.

The lubricating oil deterioration testing method and device according to the present invention configured as above can easily and accurately detect and measure the degree of deterioration of lubricating oil, and is particularly suitable for ships. It has the advantage of being suitable for measuring the degree of deterioration of lubricating oil in moving machines such as vehicles.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram illustrating the principle of a lubricating oil deterioration inspection method according to the present invention. FIGS. 2A and 2B show a detailed cross-sectional view and a potential distribution diagram of the electric double layer portion in the case of fresh lubricating oil. FIGS. 3A and 3B show a detailed cross-sectional view and a potential distribution diagram of the electric double layer portion in the case of degraded lubricating oil. FIG. 4 is a schematic diagram of a lubricating oil deterioration inspection device according to the present invention. FIG. 5 is a graph representing the results of lubricating oils tested in accordance with the present invention. 2: Column 4: Filler 6, 8: Electrode lO: Potentiometer 12.14: Pressure sensor 16: Pressure transducer 18: Signal calculation processing section 19: Display device 22: Lubricating oil supply pump Figure 1 Figure 2 Figure 3 Figure 5 Pressure P

Claims (1)

[Claims] 1) The lubricating oil to be tested is made to flow through two electrodes placed apart from each other, and the flowing potential generated between the two electrodes is measured. A lubricating oil deterioration testing method characterized by testing the degree of deterioration. 2) The method according to claim 1, wherein the lubricating oil flows in a capillary tube or a column filled with a filler, and electrodes are disposed at the inlet and outlet of the lubricating oil. 3) A column filled with a filler to allow the lubricating oil to be tested to flow, electrodes disposed at the inlet and outlet of the column, and lubricating oil connected to the electrodes to flow through the column. A lubricating oil deterioration inspection device comprising: a potentiometer for measuring the flowing potential of the column; and means for supplying lubricating oil to the column. 4) The apparatus according to claim 3, wherein the column is provided with a pressure gauge for measuring the pressure of the lubricating oil within the column and measuring the flow rate of the lubricating oil flowing within the column. 5) The device according to claim 3 or 4, wherein the filler is a spherical or cylindrical body made of glass, ceramics, synthetic resin, bisque, paper, or metal.