RU2110783C1 - Method of determination of concentration and size of impurity particles in oil or fuel and device intended for its realization - Google Patents

Abstract

FIELD: measurement technology. SUBSTANCE: taring graphs of dependences of current pulse number in electrode power supply circuit from pulse concentration and amplitude, from size of impurity particles in definite tested fuel or oil on several samples with impurities of different concentration and size of particles are obtained. To this end, samples are reduced to temperature of 18-20 C and passed through filter with cell size d=(0.90-0.96)δ, where δ is interelectrode space. Two electrodes are immersed in oil or fuel samples at distance δ=0.2 - 0.3 mm from each, and DC voltage ΔU=(0,03-0,20)E_b•δ ( where E_b is breakdown intensity for oil or fuel under test) is applied to them. Number and amplitude of current pulses in supply circuit of electrodes are measured for 1-10 min. Then the same operations are performed with oil or fuel sample under test, and concentration and size of impurities are determined by taring graphs obtained. Method may be realized by means of device having two electrodes of any shape, except for plane-parallel plates. Interelectrode distance may be changed from 0.2 to 3.0 mm. Area of each electrode is 0.1-50 sq.cm. In addition, device has power supply unit, loading resistor, capacitor, amplifier, measuring unit, indication unit, and acoustic oscillation generator. EFFECT: higher measurement results. 2 cl, 3 dwg, 2 tbl

Description

 The invention relates to measuring equipment and can be used to control the quality of oil and fuel, as well as for early diagnosis of the onset of emergency engine wear.

 There is a method of controlling the physicochemical properties of a suspension, in which two electrodes are immersed in it, a voltage is applied to them, and the number of current pulses is measured, which depends on the concentration of impurity particles, and the pulse amplitude characterizing the size of the active surface of the particles [1].

 However, this method does not ensure the accuracy of measuring the concentration of impurity particles, since not all particles contained in the suspension fall on the indicator electrode with a pulp stream. In addition, the method has a narrow range of applications: they can fix particles only in an electrically conductive medium and only substances capable of taking part in redox reactions.

 Closest to the proposed is a method for determining magnetic particles in a dielectric fluid, in which two electrodes equipped with electromagnets are immersed in it, turn them on one by one and measure the number of current pulses on the second electrode and their amplitude. These values determine the number and size of magnetic particles in a controlled volume of liquid [2].

 The application of this method, however, does not allow the determination of non-magnetic particles in oil, which constitute a significant part of engine wear products, as well as other impurities that are unacceptable in oil and fuel, in particular water.

 The present invention is aimed at expanding the scope of this method by providing the ability to measure the concentration and particle size in oil or fuel of any electrically conductive impurities, including water.

This goal is achieved by the fact that in the known method for determining the concentration and particle size of impurities in oil or fuel [2], during which two electrodes are immersed in them, a constant voltage is applied to them and the number and amplitude of current pulses in the electrode power circuit are measured, according to The invention first obtains calibration graphs of the dependences of the mentioned number of pulses on the concentration and amplitude in connection with the particle size of impurities, for which several samples of the test oil or t are prepared Pliva doped with different concentration and particle size, bring them to the temperature t = 18 - 20 ^o C, is passed through a filter with a mesh size of d = (0,90 - 0,96) • δ, where δ - inter-electrode distance is set on the electrodes the distance δ = 0.2 - 3.0 mm from each other, the voltage value is determined from the relation ΔU = (0.03-0.20) • E _samples • δ, where E _samples. - breakdown field strength for the test oil or fuel, the mentioned number and amplitude of pulses is determined over a time τ = 1 - 10 min, calibration curves of the dependences of the number of pulses on concentration and their amplitude in relation to the particle size of impurities are constructed for the test oil or fuel, then under the same conditions, determine the concentration and particle size of impurities in oil or fuel with an unknown concentration and particle size, for which they bring them to temperature t, passing through a filter with mesh size d, is set Lebanon electrodes at a distance δ from one another, is fed voltage ΔU, for the time τ measured by the number and amplitude of said pulses and the obtained calibration curve, the concentration and size of impurity particles.

 A comparative analysis of the proposed method with the prototype method [2] showed the following (see table 1).

 Thus, the proposed method contains the necessary actions on material objects - oil and fuel - (D / O) among its restrictive signs (signs 5, 7, 11, 12) and its distinctive signs (signs 2, 3, 4, 6 and 14). Therefore, it basically refers to the type of protected methods and meets the criterion of "novelty."

 The structure of this decision according to the indicated feature numbers is expressed as: 1, 5, 7, 11, 12, 16, characterized by 2, 3, 4, 6, 8, 10, 13, 14, 15.

 Therefore, this method according to the selected prototype [2] the criterion of "novelty" corresponds to the scope of the proposed claims.

 To study the inventive step of the proposal, its distinguishing features should be considered in three groups.

 The use of features 2, 3, 4 and 15 is widely known in other ways. Signs 6, 10 and 13 are known per se. However, in none of the known methods for determining the concentration and particle size of impurities in oil or fuel, these signs are not used to determine the concentration and size of non-magnetic metal particles, other impurities, and in particular water, those. in the proposed method, they exhibit a new property - expand the scope of the method. The use of signs 8 and 14 in other methods according to legal sources is unknown.

 Since the use of features 8 and 14 in methods for determining the concentration of impurities in oil or fuel is generally unknown, and the use of features 6, 10 and 13 in the proposed method creates a new property, this solution meets the criterion of "inventive step".

 A device for monitoring the physico-chemical properties of a suspension containing two electrodes, one of which is an indicator, a voltage source, a current pulse isolation unit, a pulse amplifier, amplitude discriminators and a recording device [1].

 The use of this device does not ensure the accuracy of measuring the concentration and particle size of impurities, since not all particles contained in the suspension fall on the indicator electrode with a pulp stream. In addition, this device is operable only in electrically conductive environments.

 The closest in technical essence to the proposed is a device for determining magnetic particles in dielectric fluids, containing two electrodes, power supplies, two electromagnets, a resistor and an oscilloscope [2].

 This device is operable in dielectric fluids, but it does not allow the determination of non-magnetic particles and other impurities that are unacceptable in oil and fuel, in particular water.

 The proposed device is aimed at expanding the scope of the known device by providing the ability to measure the concentration and size in oil or fuel of particles of any conductive impurities, including water.

This goal is achieved by the fact that the known device for determining the concentration and particle size of impurities in oil or fuel, containing the first and second electrodes with the first electrode with its first output, a power supply, load resistance associated with the output of the second electrode, as well as an indication unit and an acoustic oscillation generator , according to the invention further comprises a capacitor, an amplifier and a measurement unit, wherein the output of the second electrode is connected to the input of the capacitor, the output of the capacitor is connected to the second input ohm of the amplifier, the first input of which is connected to the second output of the mentioned power supply unit and the output of the load resistance, the output of the amplifier is connected to the input of the measurement unit, the output of which is connected to the input of the indicated display unit, and the interelectrode distance must be varied within δ = 0.2 - 3 , 0 mm, the electrodes should not be in the form of plane-parallel plates, and the area of each of them should be 0.1 - 50 cm ² . Therefore, this solution meets the criterion of "novelty."

 To study the compliance of the solution with the criterion of "inventive step", its distinguishing features should be considered separately. The use of each of them for the same purpose separately is widely known, including in equipment for electrical measurements. However, in the proposed combination with restrictive features, they implement an previously unknown algorithm for determining the concentration and particle size of impurities in oil or fuel by the proposed method and, thus, exhibit a deliberately new ultramount property - expanding the scope of the device due to the possibility of determining the concentration and size of particles other than magnetic non-magnetic impurities, as well as water in oil or fuel. Therefore, this solution meets the criterion of "inventive step".

 The proposed device is intended specifically for the implementation of the proposed method. Compared with other means, it allows you to implement this method most effectively. Therefore, it is declared independently.

 In FIG. 1 shows the nature of the calibration graph of the dependence of the number of current pulses in the power supply circuit of the electrodes on the concentration of impurities; in FIG. 2 - the nature of the calibration graph of the dependence of the amplitude of the current pulses on the particle size of the impurities; in FIG. 3 - diagram of the proposed device.

 The proposed method is as follows (general example of the method).

First, calibration graphs are obtained of the dependences of the number of current pulses in the electrode supply circuit on the concentration and amplitude of the pulses in relation to the particle size of the impurities in a particular test oil or fuel. To do this, prepare several samples of this oil or fuel with impurities of various concentrations and particle sizes. As impurities, particles of wear products of engines or parts of units in which the test oil or fuel is operated are selected. In the event that it is necessary to determine the presence, concentration and particle size of water in a fuel or oil before refueling them in the corresponding engine systems, water in various concentrations and with different particle sizes is introduced into the fuel or oil as impurities. After that, the oil or fuel is brought to a temperature of t = 18 - 20 ^o C and passed through a filter with a mesh size of d = (0.90-0.96) • δ, where δ is the interelectrode distance. Then, two electrodes are immersed in a container with oil or fuel, they are installed at a distance of δ = 0.2 - 3.0 mm from each other and a constant voltage is applied to them, the value of which is determined from the relation: ΔU = (0.03-0, 20) • E _samples • δ, where E _samples. - breakdown strength for the test oil or fuel. The number and amplitude of current pulses in the power supply circuit of the electrodes is measured for τ = 1 - 10 minutes. After that, calibration data are used to plot calibration curves for the dependences of the number of pulses on the concentration of impurities and the amplitude on the particle size of the impurities. Then determine the concentration and particle size of the impurities in the oil or fuel with an unknown concentration and particle size. To do this, they are brought to the same temperature t, passed through a filter with the same cell size d, electrodes are installed at the same distance δ from each other, the same voltage ΔU is applied, during the same time τ the number and amplitude of the pulses are measured, and calibration curves obtained earlier determine the concentration and particle size of impurities. The physical nature of the processes occurring in this case was first established in the studies of the applicant and is described in the "Device Operation" section.

 The significance of the features of the proposed values of the parameters of the modes of operation of the method to achieve the purpose of the invention is established experimentally and is explained as follows.

Bringing the test oil or fuel to a temperature of t = 18 - 20 ^o C is necessary to eliminate errors in measuring the concentration and particle size of impurities associated with a change in the viscosity of the oil or fuel with a change in their temperature. A decrease in temperature of less than 18 ^o C will increase the measurement time by increasing their viscosity, and an excess of 20 ^o C is impractical for reasons of increasing energy costs for heating and fire safety.

 The passage of oil or fuel through a filter with a mesh size of d = (0.90-0.96) • δ is necessary to prevent a short circuit between the electrodes in the event of particles having a size greater than the interelectrode distance. A decrease in d less than 0.9 • δ is impractical due to a decrease in the accuracy of the method, and for d more than 0.96 • δ, short circuiting of the electrodes can occur.

 With a decrease in the interelectrode distance of less than 0.2 mm, the sensitivity of the method decreases due to the impossibility of fixing coarse, 0.2 mm or more particles of impurities, and with δ more than 3 mm, the sensitivity to fine particles of impurities decreases. The interelectrode distance is selected depending on the concentration of particles of what size must be determined in the test oil or fuel.

If the voltage supplied to the electrodes is reduced to less than 0.03 • E _samples • δ, the method loses sensitivity due to a significant decrease in the average electric field strength, and an increase in voltage above 0.2 • E _samples • δ is impractical due to a significant increase in the probability of breakdown of the layer of oil or fuel between electrodes and deterioration of safety conditions during the implementation of the method.

 Reducing the time τ of measuring the amplitude and number of current pulses of less than 1 min significantly reduces the accuracy of determining the concentration and particle size of impurities, and increasing the measurement time of more than 10 minutes is impractical, since it does not increase this accuracy, but significantly increases the time spent on one measurement.

When reducing the area of each electrode less than 0.1 cm ^{2 the} sensitivity of the device is significantly reduced. With an increase in this area over 50 cm ² , the interelectrode capacitance significantly increases, which leads to the appearance of an error due to a decrease in the number and amplitude of pulses. In addition, pulses from small particles become impossible to distinguish from the background of noise.

 The electrodes should not be in the form of plane-parallel plates to ensure heterogeneity of the electric field in the interelectrode space.

 The proposed method can also be implemented using the proposed device (a particular example of the method).

This device contains (Fig. 3) two electrodes 1 and 2 with the possibility of changing the interelectrode distance from 0.2 to 3.0 mm of any shape except for plane-parallel plates and an area of 0.1 - 50 cm ² each, power supply 3, load resistance 4 , a capacitor 5, an amplifier 6, a measurement unit 7, an indication unit 8, and an acoustic oscillation generator 9.

 The device when implementing the method operates as follows.

When a constant voltage is applied to the electrodes immersed in the oil or fuel at a distance of δ from each other, the electrodes acquire opposite charges, and an inhomogeneous electric field is formed in the interelectrode space due to the shape of the electrodes, which is different from plane-parallel plates. If there are no particles of impurities in the oil or fuel, a very small direct current flows between the electrodes due to the electrical conductivity of the oil or fuel. The specific resistance of various oils and fuels is 10 ⁸ - 10 ¹³ Ohm • m, therefore, for example, at a voltage ΔU at 2 kV electrodes, an electrode area of 0.2 cm ² and a gap of 1 mm between them, this current does not exceed 0.1 - 0 , 4 μA.

 In the presence of impurity particles in the oil or fuel in the near-electrode space under the influence of an electric field, a redistribution of charges occurs in each of them, i.e. on the sides of the particle facing the electrodes, charges are induced that are opposite in sign to the charges of the respective electrodes. Due to this, the particle turns into an electric dipole, which, in addition to the orientated moment, is affected by an unbalanced force in the direction of increasing field strength, proportional to the magnitude of the charges induced in the particle and the difference in field strength between the poles of the dipole (Elementary textbook of physics. Edited by G.S. Landsberg .-- M .: Nauka, 1969, v. 2, p. 40, text under Fig. 24, 25; Strauf E.A., Course in Physics. - L .: Sudpromgiz, 1962, v. 2, p. 43). Therefore, the particle begins to move in the direction of increasing field strength to the electrode to which it was closer when the field was turned on. In contact with the electrode, the particle receives a charge from it of the same sign as it is charged by itself, since the same charged bodies repel, the particle repels from this electrode and moves to the oppositely charged electrode. Touching it, the particle is recharged with the charge of its sign, pushes away from it and moves to the oppositely charged electrode, i.e. A particle oscillates between the electrodes. All other particles of impurities perform the same motion. When each particle contacts the electrode 2, a current pulse arises in the circuit. Their number is proportional to the number of particles oscillating in the interelectrode space, and the amplitude of the pulses is proportional to the size of these particles. The current pulses cause their corresponding voltage pulses at the load resistance 4, which are fed through the capacitor 5 to the input of the amplifier 6. Here, the voltage pulses are amplified to a level sufficient to measure their quantity and amplitude by the measuring unit 7. The final information about the concentration and particle size of the impurities is given by the block Indications 8. To prevent coagulation of impurity particles, which reduces the accuracy of the measurement, the controlled oil or fuel is exposed to the acoustic field generated by the gene ATOR 9.

 Quantitative examples.

Example 1. The concentration and particle size of impurities of metal products of wear of parts of an aircraft engine were measured, in the oil system of which MK-8 oil is used, having a breakdown electric field E of the _samples. = 19.5 kV / mm. The necessary calibration schedules were obtained and the concentration and particle size of impurities in an oil with an unknown concentration and particle size were determined with the following parameters of the method operations: t = 19 ^o C, d = 0.93 • δ, δ = 1.6 mm, ΔU = 0 , 1E _samples • δ = 0.1 • 19.5 • 1.6 = 3.12 kV, τ = 5 min, the area of each electrode is 25 cm ² . The obtained calibration graphs are presented in FIG. 1 (curve 1) and FIG. 2. In FIG. Figure 2 shows only one curve, since the amplitude of the pulses does not depend on the material of the particles, but depends only on their surface area. During the measurement time τ = 5 min, 1450 pulses with an amplitude of 16 - 28 mV were recorded. From these curves, we determine the concentration of particles of 80 g / t and their size of 3.6 - 4.9 microns.

Example 2. A measurement was made of the concentration of emulsion water in a sample of RT aviation fuel having a breakdown electric field strength E _samples = 20.2 kV / mm. The necessary calibration graphs and determination of the concentration and size of water particles in a fuel sample with an unknown concentration and particle size were carried out with the following parameters of the method operations: t = 19 ^o C, d = 0.93 • δ, δ = 1.6 mm, ΔU = 0 , 1E _samples • δ = 0.1 • 20.2 • 1.6 = 3.23 kV, τ = 5 min, the area of each electrode is 25 cm ² . The obtained calibration graphs are presented in FIG. 1 (curve 2) and FIG. 2. During the measurement, 1750 pulses with an amplitude of 0.4 - 2.4 mV were recorded. According to these curves, the water concentration in the fuel is 20 g / t, and the particle size is 1.8 - 4.5 microns.

 To illustrate and confirm the possibility of obtaining a technical result — expanding the scope of the method — in the proposed intervals of operation parameters and the inability to obtain the specified technical result outside the proposed intervals, a series of experiments was conducted to determine the concentration and particle size of metallic impurities in MK-8 oil and water in RT fuel in five ways (Table 2). Methods 2 to 4 are proposed with operation parameters along the boundaries and within the proposed ranges, moreover, method 3 is described in detail in the two above examples, method 1 with operation parameters below the lower proposed limits, and method 5 is above the upper proposed limits.

 In addition, this table shows the test results of the prototype method [2] using the prototype device [2]. This method was used to determine the concentration and particle size of impurities in the same samples of MK-8 oil and RT fuel with an unknown concentration and particle size, as in the testing of methods 1 to 5.

 Tests have shown that the prototype method [2] gives underestimated concentrations of impurity particles in oil due to the impossibility of taking non-magnetic metal particles into account and is not applicable for determining water in fuel and oil. Method 1 is inoperative due to the small area of the electrodes, the small distance between them, the low electric field strength and the short measurement time. Method 5 is also inoperative due to exceeding the upper boundaries of all the proposed operation parameters.

 Thus, the proposed technical solutions satisfy all the criteria for inventions: they are new, have an inventive step and are industrially applicable.

Claims (2)

1. A method for determining the concentration and particle size of impurities in oil or fuel, during which two electrodes are immersed in them, apply a constant voltage to them and measure the number and amplitude of current pulses in the electrode supply circuit, characterized in that calibration graphs of the dependencies of the aforementioned are preliminarily obtained the number of pulses from the concentration and amplitude from the particle size of the impurities, for which several samples of the test oil or fuel with impurities of different concentration and particle size are prepared, p ivodit them to a temperature t = 18 - 20 ^o C, is passed through a filter with a mesh size of d = (0,90 - 0,96) δ , where δ - interelectrode distance, electrodes mounted in the region δ = 0.2 - 3.0 mm from each other, the magnitude of the voltage is determined from the ratio
ΔU = (0.03-0.20) • E _samples • δ,
where E _{p r o b} - breakdown voltage of the electric field for the test oil or fuel,
the number and amplitude of pulses is measured over time τ = 1 - 10 min, calibration plots of the dependences of the number of pulses on the concentration and amplitude on the particle size of impurities are constructed for the test oil or fuel, then, under the same conditions, the concentration and particle size of the impurities in the oil or fuel are determined with unknown concentration and particle size, for which they are brought to a temperature t, passed through a filter with a mesh size d, electrodes are installed at a distance δ from each other, voltage ΔU is applied to the electrodes, ix time τ measured quantity and the pulse amplitude and the obtained calibration curve, the concentration and size of impurity particles. 2. A device for determining the concentration of impurities in oil or fuel, containing the first and second electrodes, a power supply connected to the first electrode by its first output, a load resistance connected to the output of the second electrode, and an indication unit and an acoustic oscillation generator, characterized in that it additionally contains a capacitor, an amplifier and a measurement unit, while the output of the second electrode is connected to the input of the capacitor, the output of the capacitor is connected to the second input of the amplifier, the first input of which is connected to the second the output of the power supply and the output of the load resistance, the output of the amplifier is connected to the input of the measuring unit, the output of which is connected to the input of the display unit, the interelectrode distance must be variable within δ = 0.2 - 3.0 mm, the electrodes should not be in the form of plane-parallel plates , and the area of each of them should be 0.1 - 50 cm ² .

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