KR20070105775A - Apparatus of measuring the properties of fluid, and integrated system of monitoring the properties of fluid having the same - Google Patents

Abstract

An apparatus for measuring properties of fluid and an integrated type fluid property monitoring system having the same are provided to precisely measure the viscosity, temperature and electric conductivity of the fluid in real time and synthetically evaluate the state of the fluid. An apparatus for measuring properties of fluid comprises a probe(26) generating displacement in the direction against viscosity resistance. A sensor unit outputs signals according to the displacement generated by the probe(26). A controller(40) compares the output of the sensor unit with data stored in advance to obtain property data of the fluid. A piezoelectric actuator is connected to the rear portion of the probe(26) to allow the probe(26) to rotate in the axial direction. A member for preventing vibration is installed the rear end portion of the probe(26).

Description

Apparatus of measuring the properties of fluid, and integrated system of monitoring the properties of fluid having the same

1 is a view showing a schematic configuration of an apparatus for measuring physical properties of a fluid according to a first embodiment of the present invention;

FIG. 2 is a perspective view showing the structure of a mechanism part of the apparatus for measuring physical properties of fluid shown in FIG. 1; FIG.

3 is a plan view seen from the direction III of FIG.

4 is a view schematically showing a driving principle of a monomorph actuator,

5 is a plan view illustrating a state in which the probes shown in FIGS. 2 and 3 are rotated by an angle;

6 is a view showing a schematic configuration of an apparatus for measuring physical properties of a fluid according to a second embodiment of the present invention;

7 is an exploded perspective view showing the configuration of a mechanism part of the apparatus for measuring physical properties of fluid shown in FIG. 6;

8 is a cross-sectional view taken along the line VIII-VIII of FIG.

9 is an exploded perspective view showing the configuration of a modification of the mechanism shown in FIG. 7;

10 is a cross-sectional view taken along the line X-X of FIG.

11 is an exploded perspective view showing the configuration of another modification of the mechanism shown in FIGS. 7 and 9;

12 to 14 are views showing examples of the vibration preventing structure applied to the physical property measurement apparatus of the fluid according to the present invention described above,

15 and 16 is a view showing a detailed design example of the portion where the probe and the housing is connected,

17 to 25 are views showing various forms of a method of attaching an electrode for measuring electrical conductivity in a device for measuring physical properties of a fluid described above;

FIG. 26 shows an example of a bridge circuit that can be used to measure electrical conductivity, capacitance and dielectric constant using an electrode installed in an apparatus for measuring physical properties of a fluid according to the present invention; and

27 is a view schematically showing the configuration of the integrated fluid property monitoring system according to the present invention.

The present invention relates to a device for measuring physical properties of a fluid and an integrated fluid property monitoring system having the same, and more particularly, to a device for measuring physical properties of a fluid capable of precisely measuring physical properties of a fluid and blocking measurement noise on a sensor part and the same. It relates to an integrated fluid property monitoring system provided.

When oil is used, such as transmissions of turbines, engines, and vehicles that make up various machinery, and the condition of the oil affects the operation of the machinery, it is very necessary to measure various properties of the oil in real time. However, conventional measuring devices or methods of fluid properties such as (absolute) viscosity, kinematic viscosity, and density may be suitable for measuring in a laboratory, but are not suitable for providing such property data to reflect the operation of a mechanical device in real time. Therefore, there is a great need to develop a device that can be manufactured in a small size that does not significantly affect the design of the existing mechanical device and at the same time accurately measure the physical properties of the fluid.

In addition, during the manufacturing process, check the state of the molten plastics, fermentation of foods such as miso or soy sauce, or other fine chemicals, polymers, adhesives, coating paints, general paints, aqueous solutions, two-phase or In order to check the condition of multi-phase fluids, it is necessary to develop a device for measuring the physical properties of fluids that is easy to manufacture and to accurately measure the physical properties of fluids in the industrial field. very big.

On the other hand, when the fluid to be measured is engine oil or lubricating oil used in a mechanical device, the physical properties of the fluid are changed by various factors generated while the mechanical device is operating.

For example, consider lubricants used in machinery such as power turbines and automotive engine cranks. Such lubricating oil may be oxidized in contact with hot air and blow-by gas or the like between the piston and the cylinder. Alternatively, these lubricants may change their physical properties with increasing and decreasing extreme temperatures. In addition, the lubricating oil deteriorates with the use time due to the increase in viscosity and density due to the reduction of volatile content, the dilution due to the mixing of bubbles and solid carbonaceous materials, the inflow of fuel, etc. Will be degraded.

Representative automotive engine oils of industrial lubricating oil have a wide range of temperature change (about -20 ° C to + 150 ° C), and are also subjected to mechanical shocks. Therefore, lubricating oil is easily deteriorated and carbides are easily mixed. In such an extreme situation, even a well-refined lubricating oil changes its properties with time.

That is, since the lubrication characteristics are not only deteriorated, but it is difficult to use the prime mover device such as causing the cylinder to adhere to the piston, it must be replaced at an appropriate time point in consideration of the use environment and the use period. In addition, since the combustion of fuel in a state that is not optimal lubrication generates a lot of pollutants, it is necessary to properly replace the lubricating oil to reduce the pollutants.

There is a great need for the development of a new fluid property measuring device that can evaluate the deterioration of such lubricating oil or engine oil and notify the replacement time and a system that can monitor the condition of the fluid in real time.

The present invention is to solve various problems including the above problems, an object of the present invention is to provide a physical property measuring device of the fluid capable of measuring the physical properties of the fluid precisely and can block the measurement noise on the sensor unit will be. In addition, by providing a device for measuring the physical properties of the fluid to provide an integrated fluid properties monitoring system that can inform the user of the state of the fluid in real time as well as remotely.

An object of the present invention as described above, the front end portion is provided in contact with the fluid so as to generate a displacement in the direction to resist the viscous resistance; A sensor unit for outputting a signal according to the displacement generated in the probe; A control unit for supplying power from the power supply unit as an input signal to the displacement generating unit, and comparing the pre-stored data with the output of the sensor unit to calculate the physical property data of the fluid; And a piezoelectric actuator connected to the rear of the probe to rotate the probe in the axial direction, wherein the probe is provided with a physical property measuring device of a fluid, characterized in that vibration prevention means is provided at the rear end of the probe. do.

Here, the vibration preventing means preferably comprises a groove and / or step formed in the probe.

Here, the anti-vibration means is preferably a structure that is coupled to the rear of the probe and includes a groove and / or step.

Here, the probe may be provided with an electrode so as to contact the fluid to measure the electrical conductivity, capacitance and dielectric constant of the fluid.

In addition, the object of the present invention as described above, the front end portion is provided in contact with the fluid to generate a displacement in the direction to resist the viscous resistance; A sensor unit for outputting a signal according to the displacement generated in the probe; A control unit for supplying power from the power supply unit as an input signal to the displacement generating unit, and comparing the pre-stored data with the output of the sensor unit to calculate the physical property data of the fluid; A piezoelectric actuator connected to the rear of the probe to rotate the probe in an axial direction; And a housing accommodating the piezoelectric actuator which is connected to the probe and drives the probe, wherein the housing is achieved by providing an apparatus for measuring physical properties of a fluid in which vibration preventing means is provided at a portion to which the probe is connected.

Here, the vibration preventing means preferably comprises a groove and / or step formed in the housing.

Here, the probe and the housing are preferably firmly and tightly coupled so that relative displacement does not occur and fluid does not penetrate.

Here, the probe and the housing are connected to the bearing so that relative displacement can occur, and is sealed to prevent the fluid from penetrating through the bearing connection.

Here, the housing may be provided with an electrode so as to contact the fluid to measure the electrical conductivity, capacitance and dielectric constant of the fluid.

In addition, the object of the present invention as described above, the measuring unit, the calculating unit and the indicating unit, the measuring unit, the physical properties including the absolute viscosity, density, kinematic viscosity, temperature, electrical conductivity, capacitance, dielectric constant, computer value and infectious group Measure one or more of the above, the operation unit is determined by calculating one or more of the other physical properties of the fluid using the data measured in the measuring unit, the indicator is measured in the measuring unit, the calculation unit It is achieved by providing an integrated fluid property monitoring system that performs a function of notifying a user of determination data or determination data on a state of a fluid based on measured data and calculated data.

Here, the user may be spatially separated from the place where the fluid is located, and the indicator may be configured to receive information on the physical properties of the fluid from the measuring unit and the calculating unit to inform the user through an information communication line. .

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention in more detail.

1 is a view schematically showing a configuration of a device for measuring physical properties of a fluid according to a first embodiment of the present invention.

As illustrated in FIG. 1, the apparatus for measuring physical properties of a fluid according to the first exemplary embodiment of the present invention includes a mechanism 20, a power supply 30, and a controller 40.

The mechanism part 20 includes a probe 26 in contact with a fluid, a displacement generator for generating a displacement in a direction in which the probe 26 resists a viscous resistance, and a displacement generated in the displacement generator. It includes a sensor unit for outputting a signal. The displacement generating portion functions to generate a rotational displacement in a direction in which the probe 26 extending below the housing 25 of the mechanism portion rotates in place about its central axis. The detailed structure of the said displacement generating part is demonstrated later. In addition, the sensor unit functions to output a relative magnitude in which the rotational displacement of the probe differs from each other in the air and in a state of being submerged in the fluid.

The power supply unit 30 performs a function of providing power to the displacement generating unit.

The control unit 40 supplies the power from the power supply unit 30 as an input signal to the displacement generating unit, compares the stored data with the pre-stored data based on the output of the sensor unit, or calculates using a pre-stored formula. Perform the function of calculating data. Although the physical property data of the fluid which can be measured here is a viscosity normally, other physical property data, such as a density, can also be measured in some cases.

In addition, in the physical property measurement apparatus of the fluid according to the present invention, a separate thermometer (not shown) may be installed to measure the temperature of the fluid, and the temperature data may be input to the controller as a digital signal to be used for calculation of physical property data such as viscosity. It may be.

In addition, the apparatus for measuring the physical properties of the fluid according to the present invention may further include a display unit 50 to display the information on the data calculated by the control unit so that the user can see.

FIG. 2 is a perspective view illustrating a state in which a cover is opened in the apparatus for measuring physical properties of a fluid according to the first embodiment of the present invention shown in FIG. 1, and FIG. A plan view seen from the direction III is shown, and FIG. 4 is a view showing briefly the principle of construction of a piezoelectric actuator used in the mechanism of the apparatus for measuring the physical properties of the fluid shown in FIG. 2, and FIG. 5 compared with FIG. 3. The figure shows a state in which the probe is rotated a predetermined angle.

As shown in Fig. 2 and 3, the displacement generating portion constituting the mechanism portion 20 of the physical property measurement device of the fluid, from the upper side to support the probe 26 extending from the lower side to be immersed in the fluid to be measured viscosity at least a portion. Two piezoelectric actuators 21 are included. It is preferable that the said probe 26 is cylindrical shape, and it is preferable that the length of the part submerged in the fluid of the viscosity measurement object of the lower part is 5 times or more of diameter. One end of the piezoelectric actuator 21 is fixed to the probe 26 and the other end of the piezoelectric actuator 21 is fixed to the housing 25.

It is preferable that the probe 26 has a cylindrical shape, considering that the shape of the ideal mechanism part when measuring the viscosity of the fluid is an infinitely long boundary system, and the side effect can be minimized. This is because the cylindrical shape is suitable for manufacturing for industrial use. The longer the length of the probe 26 is, the longer the length of the probe 26 is, because the longer the length can avoid the effect of the corner effect, and if the length is longer than 5 times, the corner effect becomes negligible.

It is preferable that the outer shape of the probe 26 is a cylinder, and the inside is made of a hollow hollow or filled cylinder as shown in the drawings.

Each of the piezoelectric actuators 21 includes a plate-shaped elastic body 23 that is thin and long compared to its width, and piezoelectric elements S1 and S2 attached to one surface of the elastic body 23.

When the piezoelectric actuator 21 shown in Figs. 2 and 3 is arranged in a state where one end is fixed as shown in Fig. 4, and a voltage is applied to both surfaces of the piezoelectric element S1, the piezoelectric element S1 Is transformed. The direction of deformation depends on the polarization direction of the piezoelectric element S1 and the voltage application direction of which the + or − voltage is applied. In any case, the polarization direction and the voltage application direction of the piezoelectric element S1 may be adjusted so that the length of the piezoelectric element S1 is longer or shorter.

If the length of the piezoelectric element S1 is adjusted to be longer as a voltage is applied, the piezoelectric actuator 21 is deformed in one direction as indicated by a dotted line in FIG. 4. The amount of deformation of the piezoelectric actuator 21 may be adjusted by adjusting the magnitude of the applied voltage.

When the appropriate voltage is applied from the mechanism 20 shown in FIG. 3 using the piezoelectric actuator 21 driven as described above, the probe 26 may be rotated as shown in FIG. 5. When the applied voltage is removed, the state shown in FIG. 3 is restored. By this principle, the displacement generator is operated.

On the other hand, in order to drive the piezoelectric actuator 21, even if a monomorphic form (monomorph) attached to the piezoelectric elements (S1, S2) on only one surface of the elastic body 23 can cause the above motion, if the piezoelectric elements ( When the piezoelectric actuator 21 is configured in a bimorph form to which S1, S2, R1, and R2 are attached, the displacement can be further increased.

In addition, in the state where the piezoelectric actuator 21 is configured in the form of bimorph, only the piezoelectric elements S1 and S2 on one side may be used for driving, and the piezoelectric elements R1 and R2 on the other side may be used for sensing. That is, the piezoelectric elements R1 and R2 which are not used for driving can be used as the sensor part among the mechanism parts constituting the fluid property measuring apparatus according to the first embodiment of the present invention.

As shown in FIG. 3, in the state in which the piezoelectric elements S1, S2, R1, and R2 are disposed on both surfaces of the elastic body, a voltage is applied to the piezoelectric elements S1 and S2 on one side thereof so that the probe 26 is predetermined. As the piezoelectric elements S1 and S2 on one side are rotated at an angle, the piezoelectric elements R1 and R2 on the other side that are deformed together generate a voltage proportional to the amount of deformation due to the physical characteristics of the piezoelectric elements. As such, when the voltage generated by the piezoelectric elements R1 and R2 on the other side is measured, the rotational displacement of the probe 26 may be measured. In addition, the rotational displacement of the probe 26 in the atmosphere at the time of applying a predetermined voltage and the rotational displacement of the probe 26 in the state in which the probe 26 is immersed for a predetermined depth or more in the fluid to be measured for viscosity By measuring this, the viscosity of the fluid can be calculated.

Meanwhile, as illustrated in FIGS. 2 and 3, the plurality of piezoelectric actuators 21 are preferably disposed at regular intervals from each other. This is because the piezoelectric actuator 21 can uniformly rotate the probe 26 only when the force acting on the probe 26 is uniform. In addition, the piezoelectric actuators 21 are shown in a fixed state while being substantially perpendicular to the probe 26 in FIGS. 2 and 3, but the present invention is not limited thereto, and the piezoelectric actuators 21 may have the probe ( It also includes the case where it is fixed while having an inclination in 26).

Second Embodiment

6 is a view showing the configuration of the physical properties of the fluid measuring apparatus according to a second embodiment of the present invention, Figure 7 is an exploded perspective view schematically showing the configuration of the mechanism of the physical properties measuring device of the fluid shown in FIG. 8 is a cross-sectional view taken along the line VIII-VIII of FIG.

As shown in FIG. 6, the apparatus for measuring physical properties of a fluid according to the second exemplary embodiment of the present invention includes a mechanism unit 120, a power supply unit 30, and a controller 40 as in the first exemplary embodiment.

The second embodiment differs from the first embodiment described above in that the structure of the mechanism 120 is different from that of the mechanism 20 of the first embodiment. The structure of the mechanism part 120 in 2nd Example is as follows.

As shown in FIG. 7, the mechanism 120 of the apparatus for measuring physical properties of the fluid according to the second embodiment of the present invention includes a hollow cylindrical probe 126 having a thread 126a formed at one side thereof, and the probe 126. Piezoelectric actuator 21 is installed on the inside. Two piezoelectric actuators 21 are installed, and the ends of the piezoelectric actuators 21 are fixed to the outer finishing member 128 and the inner finishing member 129 which respectively close both ends of the probe 126. The outer finisher 128 is fixed with the probe 126 outside the end of the probe 126, the inner finisher 129 is fixed with the probe 126 inside the probe, thereby substantially The piezoelectric actuators 21 are arranged as fixed to both ends of the probe 126.

The two piezoelectric actuators 21 are arranged to be substantially 180 degrees with respect to the central axis of the probe 126, and since being disposed substantially parallel to the probe 126 is advantageous in reducing the space desirable. However, the piezoelectric actuator 21 is not necessarily arranged in parallel with the probe 126, but is also included in the present invention when the piezoelectric actuator 21 is disposed in an inclined manner without being disposed in parallel.

 As in the first embodiment, the piezoelectric actuator 21 has a shape in which the piezoelectric elements S1 and S2 for driving and the piezoelectric elements R1 and R2 for sensing are attached to the elastic body 23, respectively.

The probe 126 may be fixed to the wall surface of the container 160 containing the viscosity measurement fluid 70 by using the thread 126a formed on one side, and in the fixed state of the piezoelectric actuator 21. It is possible to measure the viscosity while causing rotational displacement by driving. The measurement method of the viscosity is the same as in the first embodiment.

9 shows a variant of the mechanism shown in FIG. 7, and FIG. 10 is a cross-sectional view taken along the line X-X of FIG. 9.

As shown in Fig. 9 and Fig. 10, in the mechanism part of the present modification, four piezoelectric actuators 21 are used and arranged at substantially right angles to each other. When four piezoelectric actuators 21 of the same type are used as described above, the rotational displacement of the probe 126 can be further increased, and the sensing piezoelectric elements R1 and R2 attached to the respective piezoelectric actuators 21 can be increased. ) Has the advantage of reducing the measurement error by combining the measured values.

11 shows another modification of the mechanism shown in FIG. 7.

As shown in FIG. 11, in the mechanism part of this modification, the mass part 328 is attached to the edge part of the probe 126, ie, the end surface of the outer finishing material 128. As shown in FIG. As the mass portion 328 is further attached, the rotation momentum of the probe 126 may be greater during the operation of the probe 126 causing the rotational displacement, which may help to measure the viscosity more accurately.

Also in the case of the probe 126 shown in Figs. 6 to 11, it is preferable that the length of the portion in contact with the fluid is longer than five times as long as the corner effect can be avoided.

12 to 14 show examples of applying the vibration preventing structure to the apparatus for measuring physical properties of a fluid according to the present invention described above.

Vibration occurs during operation in probes 26 and 126 in contact with the fluid while rotational displacement occurs. This vibration is likely to be included as noise in the measurement when measuring the output value for the pulse signal input value that causes rotational displacement. This raises the need to block this and improve the signal to noise ratio. As an example of such a vibration blocking structure, a structure in which the groove 25a or the step 25b is formed as shown in FIGS. 12 to 14 may be applied.

FIG. 12 shows a plurality of steps 25b and grooves 25a formed in the housing 25 ′ shown in the embodiment described with reference to FIGS. 1 and 2. When the housing 25 illustrated in FIGS. 1 and 2 is deformed into a form in which the step 25b and the groove 25a are formed as shown in FIG. 12, vibration generated during operation in the probe 26 is measured by the sensor unit. This can prevent the signal from being included as noise. However, the structure for forming the step 25b and the groove 25a is not limited to the structure as shown, and can be variously modified. On the other hand, as shown in FIG. 12, when the thread 26a is formed at a specific step among the steps 25b, the apparatus 20 for measuring physical properties of the fluid according to the first embodiment of the present invention is the same as that shown in FIG. It is also possible to use in combination with the wall of the container 160 containing the fluid.

13 and 14 illustrate examples in which the anti-vibration structure is applied to the second embodiment described with reference to FIGS. 6 to 11. FIG. 13 illustrates an example in which a vibration preventing structure is formed inside the container 160 from a portion engaged with the container 160 in the second embodiment. 14 is an example in which the vibration preventing structure is formed outside the container 160 in the second embodiment.

In the examples shown in FIGS. 12 to 14, the probes in common contact with the fluid and the sensor parts at the rear thereof are structurally clearly distinguished, thereby preventing the vibration of the probes from being included as noise in the signal measured at the sensor part at the rear. . The structure of the formation of the step and the groove is not limited to the illustrated and may be variously changed. In addition, the step or groove formed portion may be separately processed and combined with the probe, the step and the groove may be formed in a state that is integrally processed with the probe.

15 and 16 show a detailed design example of the portion where the probe and the housing are connected.

In the apparatus for measuring the physical properties of a fluid according to the present invention, the probe is made to be connected with the housing, and the probe is configured to generate a rotational displacement relative to the housing. In this case, the influence on the measured vibration sensitivity may vary depending on the design of the connection part. For example, in case of welding as shown in FIG. 15 and in case of using a low-loss coupling which reduces a loss of transmission torque by using a bearing, a binding material and / or an adhesive as shown in FIG. Since the vibration sensitivity is different from each other, it is necessary to go through different calibration procedures in measuring the physical properties of the fluid. However, in general, when welding or forming a low-loss coupling portion, the evaporation of the sample may be a problem, so it must be combined to maintain a high degree of closeness. In the present invention, the detailed design of the connection portion of the probe and the housing is not limited, but is preferably designed in the form shown in FIG. 15 or 16.

Until now, only the configuration that can measure the temperature and viscosity in the physical property measurement device of the fluid has been described. Of course, when measuring temperature and viscosity, the density and kinematic viscosity can also be measured. By the way, when the fluid to be measured is an engine oil or lubricating oil used in a mechanical device, the physical properties of the fluid are changed by various factors generated while the mechanical device is operating.

For example, consider lubricants used in machinery such as power turbines and automotive engine cranks. Such lubricating oil may be oxidized in contact with hot air and blow-by gas or the like between the piston and the cylinder. Alternatively, these lubricants may change their physical properties with increasing and decreasing extreme temperatures. In addition, the lubricating oil deteriorates with the use time due to the increase in viscosity and density due to the reduction of volatile content, the dilution due to the mixing of bubbles and solid carbonaceous materials, the inflow of fuel, etc. Will be degraded.

Representative automotive engine oils of industrial lubricating oil have a wide range of temperature change (about -20 ° C to + 150 ° C), and are also subjected to mechanical shocks. Therefore, lubricating oil is easily deteriorated and carbides are easily mixed. In such an extreme situation, even a well-refined lubricating oil changes its properties with time.

That is, since the lubrication characteristics are not only deteriorated, but it is difficult to use the prime mover device such as causing the cylinder to adhere to the piston, it must be replaced at an appropriate time point in consideration of the use environment and the use period. In addition, since the combustion of fuel in a state that is not optimal lubrication generates a lot of pollutants, it is necessary to properly replace the lubricating oil to reduce the pollutants.

Indicators for evaluating deterioration of such lubricating oil or engine oil are the amount of sludge in oil, viscosity, total acid number (TAN), and the like. Any one of these variables alone cannot assess the exact extent of the deterioration and should be assessed and judged comprehensively.

Therefore, in order to measure the physical properties of the fluid according to the present invention, to add a configuration that can further measure the electrical conductivity, to determine the deterioration of the lubricant and engine oil viscosity, density, kinematic viscosity, dielectric constant, capacitance and electrical conductivity Considering these factors, the degree of deterioration of lubricating oil and engine oil can be evaluated. That is, the electrical conductivity measurement function is added to the above-described viscosity and temperature measurement functions, so that the electrical properties including the electrical conductivity of the fluid can be considered simultaneously with the physical properties of viscosity, temperature, density, and kinematic viscosity.

Electrical conductivity refers to the degree to which a solution can carry an electric current, and refers to an electrical property capable of quickly evaluating ionic strength in a solution. The unit used is expressed as ohm ^-1 or mho, which is the inverse dimension of electrical resistance. mho is commonly used in S (Siemens) unit, which is an international system of units, and uses many units of mS / m (milli-Siemens / meter) and μS / cm (microSiemens / centi meter). And mS / m is 10 S / cm (or 10 mhos / cm).

The measuring principle of the electrical conductivity used in the present invention is as follows.

Applying a constant voltage to two different polarity electrodes in contact with the lubricant or oil sample causes the applied voltage to flow, and the magnitude of the current flowing depends on the conductivity of the solution. In this case, the resistance R of the solution or the oil sample may be expressed by the following Equation 1.

Where θ is the specific resistance (Ω · cm), t is the distance (cm) between the two electrodes, and A is the cross-sectional area (cm2) of the electrode.

The electrical conductivity C can be expressed by the following equation (2).

Here, K (= 1 / θ) is a non-conductivity (mho / cm), and the cell constant value (A / t) can be determined and used through calibration. Therefore, the measurement result is obtained by multiplying the measured conductivity value (mho) by the cell constant (cm-1) and displaying the conductivity value of the sample in mho / cm. Since the electrical conductivity is largely influenced by the temperature difference (about 2% / ℃), the measurement reference value is used as an evaluation criterion for deterioration of oil by setting a constant reference temperature (eg, 25 ℃).

In order to measure the electrical conductivity, two or more electrodes should be installed at the part contacting the fluid. Hereinafter, various embodiments of the structure in which the electrode is installed will be described.

17 to 22 are views showing various forms of attaching an electrode for measuring electrical conductivity in the apparatus for measuring physical properties of the fluid described above.

FIG. 17 illustrates a form in which electrodes are installed on sidewalls of a housing in an apparatus for measuring physical properties of a fluid of the type described with reference to FIGS. 1 and 2. As shown in FIG. 1, in the physical property measurement apparatus of the fluid shown in FIGS. 1 and 2, the physical properties of the fluid are measured while a part of the housing is immersed in the fluid, in which case the electrode is in contact with the fluid. The electrode can be installed on the side wall of the.

FIG. 18 illustrates an embodiment in which the conductivity measuring electrodes are attached to the lower surface of the housing in order to facilitate contact with the lubricating oil in the apparatus for measuring physical properties of the fluid described with reference to FIGS. 1 and 2.

FIG. 19 illustrates a form in which electrical conductivity measuring electrodes are attached to the side of the probe when the physical property measuring device of the fluid of the type described with reference to FIGS. 6 to 11 or a modification thereof is configured as a cylindrical protrusion.

20 to 22 are views showing a configuration different from the arrangement of the electrodes shown in FIGS. 17 to 19 when the conductive electrodes are configured in an annular shape. When the electrode is configured in an annular shape, the overall electrical conductivity can be measured even when the electrical conductivity of the fluid is locally different in a specific direction with respect to the probe.

23 to 25 show examples of the case where the conductive electrodes are arranged in multiple numbers. In the case of providing electrodes in multiples, it is preferable to install an even number between 4 and 12 electrodes.

Electrical conductivity also includes electrolytic properties such as total dissolved solids (TDS), salinity (salinity), total acid number (TAN) indicating the degree of oxidation of the oil, and acidic substances produced during combustion of the fuel. Since it is proportional to the total base number (TBN) indicating the degree of ability to neutralize, it can be functionalized as shown in Equations 3 and 4 below.

That is, the acid value and the base value may be expressed as a product of a function of electrical conductivity and a function of viscosity (μ), density (ρ), and temperature (T).

These functions are determined by calibration experiments and can be linear or nonlinear functionalization.

The effective use range of engine oil should be maintained at least 4, preferably at least 6 for TAN, and at least 1, preferably at least 2 for TBN. Apparatus for measuring the physical properties of fluids according to the present invention, the TAN is preferably 1 to 10 mgKOH / g, the total salt can be measured in the range of 0.5 to 5 mgKOH / g, through which the service life of the engine oil or lubricant , The degree of contamination and accurate indication of the time of replacement is possible.

These values of electric conductivity, computer value, and infectious value can be evaluated in various sites such as lubricant and water pollution, which are commonly used in compressors, hydraulic equipment, turbines, gears, pumps, and natural gas engines, as well as in evaluating lubricating oils in diesel and gasoline engine cars. Application is possible.

The conductivity measurement method may be measured by using a circuit using an AC bridge that supplies AC power in a voltage range of 0.1 to 24V and a frequency of 1kHz to 1MHz to electrodes having different polarities.

Capacitance or dielectric constant can be measured from the conductivity measurements from the current and voltage data applied while measuring the conductivity, and these measurement variables can detect the increase or decrease of the capacitance due to oil deterioration. To be. The change in capacitance value can be monitored to find out how the impurities are contained, and if the capacitance value rises above the threshold, immediate replacement action can be ordered to prevent damage to the engine or industrial machinery.

Hereinafter, a method of measuring electrical conductivity, capacitance, and dielectric constant will be described in more detail. As mentioned above, it is convenient to use an AC bridge circuit for the measurement of electrical conductivity, capacitance and dielectric constant. FIG. 26 shows a configuration example of an AC bridge circuit in the case where an electrode provided in the apparatus for measuring physical properties of a fluid according to the present invention has the values of the resistor Rx and the capacitor Cx at the same time.

As shown in FIG. 26, by using a matching resistor (Rs) and a capacitor (Cs) to adjust to a null voltage to measure the electrical conductivity and resistance impedance of the fluid, through which the capacitance (Cx) and the dielectric Determine the constant ε.

First, since the electrical conductivity is the inverse of the resistance impedance, the electrical conductivity can be measured from Equation 5 below.

C = 1 / Z = I (t) / V (t)

Here, the voltage V and the current I become the RMS voltage applied at the AC frequency and the measured current value.

This general formula refers to an ideal case where the unit area of the distance and the conductive plate is 1, and in actual application, it is highly dependent on the type and structure of the measuring cell. Therefore, the cell constant is determined using a standard solution manufactured according to a certain mechanical and electrical specification. Corrected and applied.

Determination of the cell constant can be obtained from the following equation 6 using the sensor.

Ke = C × k = I (t) / V (t) × k

Ke is the electrical conductivity to be measured, C is the unit electrical conductivity measured by the electrical method, k is the cell constant determined according to the type and specification of the manufactured sensor.

In general, the capacitance Cx may be represented by Equation 7 below.

Cx = Q / V (t)

Here, Q represents the charge amount, and V (t) represents the voltage.

If this is developed in differential form, it can be expressed by the following Equation (8).

Cx = dQ / dV

Since the total charge amount may be expressed as a product of current and time, the charge amount may be expressed as in Equation 9 below.

dQ = Cx × dV = dI × dt

Therefore, the capacitance can be expressed as Equation 10 below.

Cx = dI / dV × dt = dt / dZc

In addition, the capacitance can be expressed as Equation 11 below.

 Cx = j2πfZc

Accordingly, Zc can be obtained from the phase difference information of the imaginary part in the circuit of FIG. 26, and as a result, the capacitance Cx for each state of the sample can be obtained. The phase difference measurement method can be measured using a general zero-crossing technique and a simple logic gate.

The capacitance Cx of the fluid measured in this way is compared with the reference value Co of the vacuum measured beforehand for a device having a specified mechanical and electrical specification, as shown in Equation 12 below. It can be presented in terms of.

ε = Cx / Co

Where ε is the defined relative dielectric constant or relative permittivity.

As the temperature increases, the conductivity and dielectric constant increase greatly, and the resistivity decreases significantly. Viscosity and kinematic viscosity decrease significantly with increasing temperature. The temperature dependence of the device for measuring TAN and TBN cannot also be ruled out, so the design uses a platinum resistance thermometer (PRT) or a thermocouple of the appropriate temperature rating to measure the temperature and the temperature dependence. Calibrate to compensate. Products manufactured to proper production standards do not need to be calibrated for all products and can be managed by sampling techniques.

In the apparatus for measuring physical properties of a fluid according to the present invention, high frequency alternating current is applied to an electrode through a bridge circuit, and the variables such as the magnitude of current and impedance, phase, etc. of a single pair or multiple pair array electrodes are measured. In addition, the fluid state can be monitored by integrating the TAN, TBN, capacitance, electric conductivity, dielectric constant, etc. of the target fluid together with viscosity, density, and kinematic viscosity values measured by driving the probe.

27 is a view schematically showing the configuration of the integrated fluid properties monitoring system according to the present invention.

As shown in FIG. 27, the integrated fluid property monitoring system 800 includes a measuring unit 810, a calculating unit 820, and an indicating unit 830.

The measuring unit may be a device for measuring the physical properties of the fluid according to the present invention described above. The output value of the measuring unit may be viscosity, temperature, electrical conductivity, etc. measured in the physical property measuring device of the fluid, or may be raw data for calculating such a value.

The calculating unit performs a fluid property calculation function and a fluid state evaluation function. The arithmetic unit includes a memory unit for storing measured data, a set numerical value, an algorithm used for arithmetic operation, etc. for a basic arithmetic operation, and an arithmetic processing unit for reading a necessary information from the stored memory and performing the arithmetic operation. The operation processing unit may include a microprocessor or a digital signal processor (DSP). The operation unit calculates various physical properties of the fluid based on the data input from the measurement unit, and evaluates the current state of the fluid through comparison with preset values. The output value of the operator may include data such as viscosity, temperature, electrical conductivity, kinematic viscosity, density, capacitance, acid value, infectivity, dielectric constant, and the like, and may include an evaluation result of a fluid state.

The indicating unit functions to inform the user of the result output from the calculating unit, and includes an electronic control unit (ECU). The electronic control unit may include a display unit in digital or analog form.

A series of data such as absolute viscosity, temperature, kinematic viscosity, density, electrical conductivity, computational value, infectivity, capacitance, and dielectric constant of a measured fluid is comprehensively analyzed and calculated by an integrated microprocessor or digital signal processor. Star instructions are output to the electronic control unit. The electronic control unit will immediately notify the driver or operator of this situational output.

Judgment in the computational section and immediate notification in the indication section, for example, prepares to replace the lubricant when the viscosity or density increases by more than 15%, or instructs immediate replacement when it increases by more than 20%, or diesel of fuel. Dilution effect due to the inflow of oil or gasoline into the engine oil may be detected by taking immediate action by detecting the viscosity or the decrease in capacitance or viscosity value below a predetermined reference range.

These measurements can also be used to indicate how to use automotive and industrial equipment, along with driving behavior analysis data to record user habits, and in particular to indicate the exact cycle of replacement of lubricants or engine oils. The fluid property monitoring system, which can simultaneously measure or calculate the viscosity, density, temperature, conductivity, and capacitance of fluids, is applicable to the lubrication process of gear oils and a wide range of industrial machines, as well as engine oils in vehicles. Do.

For example, the integrated fluid property monitoring system according to the present invention, the detection of engine oil degradation such as automobiles, ships, aircraft, prime mover, the viscosity and physical properties of bunker C oil fuel flowing into the marine diesel engine, the inside of the transmission transformer Specific real-time monitoring of insulation of insulation oil, detection of degradation of turbine lubricating oil of generator, measurement of viscosity and physical properties in polymer, polymer or ink manufacturing process, industrial devices requiring measurement of other acid value and infectious value, viscosity, density of food fermentation process or It can be used for measuring the maturity level, viscosity measurement in paint manufacturing process, and real-time measurement of polymerization degree in other polymer polymerization reaction processes. In addition, in these operations, all users' behaviors or driving behaviors and driving history data from the time of shipment of the related machinery to the disposal time may be documented and used for optimal operation and control of individual devices or vehicles.

The integrated fluid property monitoring system according to the present invention contributes to a reduction in operating costs, operation and operating costs in mechanical devices such as automobiles and large turbines.

According to the integrated fluid property measurement system according to the present invention, in the lubrication system of an engine oil or an industrial turbine, such as an automobile, the physical properties of the engine oil or lubricating oil are measured, judged integrally, and the appropriate replacement time is indicated according to the result. Can be. As a result, it is possible to contribute to the prevention of environmental pollution due to waste oils caused by unnecessary engine oil or lubrication oil replacement, and to greatly reduce unnecessary energy and economic losses due to late replacement of engine oil or lubricating oil.

Meanwhile, the integrated fluid property monitoring system according to the present invention can be used as a remote monitoring system using the Internet (TCP / IP) and an industrial communication bus.

As described above, according to the present invention, it is possible to provide an apparatus for measuring physical properties of a fluid which is small in size and capable of accurately measuring real-time viscosity, temperature, and electrical conductivity. In particular, by using the piezoelectric element as the actuator and the sensor, the operation of the mechanism part can be precisely controlled by the voltage signal, and the viscosity can be accurately measured according to the viscosity of the fluid to be measured.

In addition, according to the measuring device of the physical properties of the fluid according to the present invention, it is possible to measure the kinematic viscosity, density, capacitance, acid value, infectivity, dielectric constant, etc. on the basis of the viscosity, temperature, electrical conductivity of the fluid to synthesize the state of the fluid Evaluation is possible.

Apparatus for measuring the physical properties of fluids according to the present invention has a structure that is easy to fabricate a small size is suitable for use in the industrial field to check the state of the raw materials or products in the fluid state during the manufacturing process. In addition, it is possible to manufacture a mechanical device such as a turbine or an engine so small that it can be mounted without changing the existing design of the mechanical device. This enables to check the state of lubricants and the like that greatly affect the operation of the mechanical device. Suitable for

So far, the present invention has been described with reference to the embodiments shown in the drawings, which are merely exemplary and will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. . Therefore, the true technical protection scope of the present invention should be defined by the technical spirit of the appended claims.

Claims (11)

Probes provided so that the tip portion is in contact with the fluid to generate a displacement in a direction to resist the viscous resistance; A sensor unit for outputting a signal according to the displacement generated in the probe; A control unit for supplying power from the power supply unit as an input signal to the displacement generating unit, and comparing the pre-stored data with the output of the sensor unit to calculate the physical property data of the fluid; And A piezoelectric actuator connected to the rear of the probe to rotate the probe in an axial direction, The probe has a physical property measurement device, characterized in that the vibration preventing means is provided at the rear end of the probe. The method of claim 1, The vibration preventing means comprises a groove and / or step formed in the probe physical properties of the fluid, characterized in that. The method of claim 1, The vibration preventing means is a physical property measurement device of the fluid, characterized in that the structure is coupled to the rear of the probe and comprises a groove and / or step. The method of claim 1, wherein The probe is a physical property measuring device of the fluid, characterized in that the electrode is installed in contact with the fluid to measure the electrical conductivity, capacitance and dielectric constant of the fluid. Probes provided so that the tip portion is in contact with the fluid to generate a displacement in a direction to resist the viscous resistance; A sensor unit for outputting a signal according to the displacement generated in the probe; A control unit for supplying power from the power supply unit as an input signal to the displacement generating unit, and comparing the pre-stored data with the output of the sensor unit to calculate the physical property data of the fluid; A piezoelectric actuator connected to the rear of the probe to rotate the probe in an axial direction; And A housing connected to the probe and containing a piezoelectric actuator for driving the probe, Device for measuring the physical properties of the fluid, characterized in that the vibration preventing means is installed in the part connected to the probe. The method of claim 5, The vibration preventing means includes a physical property of the fluid, characterized in that it comprises a groove and / or step formed in the housing. The method of claim 5, And the probe and the housing are firmly and tightly coupled to each other such that relative displacement does not occur and fluid does not penetrate. The method of claim 5, The probe and the housing are connected to a bearing such that relative displacement can occur; Device for measuring the physical properties of the fluid, characterized in that the sealing is prevented from penetrating the fluid through the bearing connection. The method of claim 5, wherein The apparatus of claim 1, wherein an electrode is installed in the housing so as to be in contact with the fluid to measure electrical conductivity, capacitance, and dielectric constant of the fluid. Including a measuring unit, arithmetic unit, and indicating unit, The measuring unit measures any one or more of the physical properties, including absolute viscosity, density, kinematic viscosity, temperature, electrical conductivity, capacitance, dielectric constant, acid value and total value, The calculation unit is determined by calculating one or more of the other physical properties of the fluid using the data measured in the measurement unit, The indicator unit performs a function of notifying the user of data measured by the measuring unit, data calculated and calculated by the calculating unit, or judgment data on the state of the fluid based on the measured data and the calculated data. Monitoring system. The method of claim 10, The user is spatially separated from where the fluid is located, The indicator unit is integrated fluid property monitoring system that can receive information on the properties of the fluid from the measuring unit and the calculation unit through the information communication line to notify the user.

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