A flow-adaptive particle size counter

Abstract

This application belongs to the technical field of fluid particle size detection and specifically discloses a flow-adaptive particle size counter, comprising a housing, a light source, a light-transmitting sheet, a photoelectric sensor, a pressure differential sensor, an analysis circuit board, and a processor. The housing has a sampling channel for connecting to a medium pipeline; the pressure differential sensor measures the pressure difference ΔP across the sampling channel and outputs a current I, which is accumulated and converted into a voltage U by a current integration circuit in the analysis circuit board; light emitted by the light source passes through the light-transmitting sheet and the sampling channel and strikes the photoelectric sensor, which generates voltage pulses based on particle projections; and the processor determines particle size based on the number N of voltage pulses and the voltage U within a sampling period T. The counter of this application can adaptively detect particle size even under flow fluctuations.

Description

Technical Field

[0001] The present application belongs to the technical field of fluid particle size detection, and more specifically, relates to a flow-adaptive particle size counter. Background Art

[0002] Currently, fluids such as oil, water, and gas are widely used in various fields of production and life. Due to wear of moving components within the system, erosion by external contaminants, and chemical deterioration of the fluid, the fluids in operation are inevitably contaminated by solid particles. Excessive levels of solid particles in the fluid can accelerate wear of moving parts, clog tiny flow channels, and even damage precision components, making timely filtration essential.

[0003] Currently, particle size is one of the important indicators for judging the contamination level of fluid media. A particle counter is usually used to measure the number of particles in a certain volume of oil and compare it with the corresponding standards. In related technologies, traditional online particle counters cannot usually be installed directly on the main pipeline and require bypass installation. Furthermore, hydraulic valves or metering pumps are usually required to provide fluid power to drive the flow of oil in the particle counter. However, in critical systems such as hydraulic systems and lubrication systems at industrial sites, system pressure is often difficult to maintain stable. For example, the hydraulic system is frequently pressurized and depressurized, and the lubrication system pressure also needs to be adjusted in real time. This causes the flow of metering pumps and hydraulic valves to fluctuate dramatically, resulting in poor measurement results. Summary of the Invention

[0004] In response to the defects or improvement needs of the existing technology, the present application provides a flow-adaptive particle size counter, which aims to improve the problem that traditional particle size counters are difficult to detect under flow fluctuations.

[0005] The present application provides a flow-adaptive particle counter, which specifically includes a housing, a light source, a light-transmitting sheet, a photoelectric sensor, a differential pressure sensor, an analysis circuit board, and a processor, wherein:

[0006] The housing has a sampling channel, and the housing is used to connect with the medium pipeline. When the fluid in the medium pipeline flows through the sampling channel, the pressure difference generated in the sampling channel It is linearly related to the medium flow rate Q;

[0007] The differential pressure sensor is used to measure the pressure difference at both ends of the sampling channel , and output in real time with the pressure difference The current I is linearly related and is converted into a voltage U by the current integration circuit in the analysis circuit board;

[0008] The light source and the photoelectric sensor are arranged on opposite sides of the sampling channel. The light-transmitting sheet is used to separate the light source, the photoelectric sensor and the sampling channel. The light emitted by the light source passes through the light-transmitting sheet and the sampling channel and then illuminates the photoelectric sensor. The photoelectric sensor forms a voltage pulse based on the projection of particles in the light.

[0009] The processor is configured to determine the granularity based on the number N of voltage pulses within a sampling period T and the voltage U.

[0010] Through the above technical solutions conceived in the present application, compared with the existing technology, the particle size counter has a sampling channel with linear characteristics. Through the conversion of the pressure difference sensor and the current integration circuit, the fluctuating flow rate that is difficult to detect is converted into a voltage that is easy to detect. It is suitable for industrial sites where the pressure / flow rate is constantly changing, and expands the application scope of the particle size counter, so that the counter can adaptively perform particle size detection under flow fluctuations; in addition, the counter relies on dynamic sampling of the fluid in the medium pipeline, reducing accessories such as hydraulic valves or metering pumps, making the installation method of the counter relatively simple and convenient.

[0011] As a further preference, the sampling channel comprises a capillary tube, one end of the capillary tube is provided with a medium inlet, and the other end of the capillary tube is radially connected to a branch tube.

[0012] As a further preference, the capillary tube is a straight tube that is thick in the middle and thin at both ends, and the middle tube section is a square tube and the tube sections at both ends are round tubes.

[0013] As a further preference, the diameter of the branch pipe is 2.5-3.5 times the diameter of the capillary tube, and the Reynolds number of the fluid in the capillary tube is Re≤500.

[0014] As a further preference, a plurality of branch tubes are provided, and the plurality of branch tubes are radially distributed at the end of the capillary tube.

[0015] As a further preferred embodiment, the current integration circuit includes a resistor, a capacitor and a switch, the resistor, the capacitor and the pressure difference sensor form a series loop, and the switch is connected in parallel with the capacitor.

[0016] As a further preferred embodiment, the voltage U accumulated within the period T is calculated using the following formula:

[0017] ,

[0018] in, is the capacitance value in the current integration circuit, and t represents the time variable.

[0019] As a further preferred embodiment, the particle size It can be calculated using the following formula:

[0020] ,

[0021] Among them, K1 is the pressure difference Relationship coefficient with medium flow Q; is the current I and the voltage difference The relationship coefficient, is the capacitance value in the current integration circuit.

[0022] As a further preferred embodiment, the shell is used to be detachably connected to the bend of the medium pipeline. After the detection end of the shell is extended into the interior of the medium pipeline, a gap is left between the detection end and the inner wall of the medium pipeline. It is located in the medium pipeline, and the medium inlet of the sampling channel faces the liquid inlet of the bend.

[0023] As a further preference, the differential pressure sensor is equipped with a built-in inspection circuit for detecting whether the differential pressure sensor is faulty.

[0024] In general, the above technical solutions conceived by this application have the following technical advantages compared with the existing technologies:

[0025] 1. This particle counter utilizes a T-shaped flow channel, where the pressure differential is linearly related to the flow rate. Through the conversion of the pressure differential sensor and the current integration circuit, the difficult-to-detect fluctuating flow rate is converted into an easily detectable voltage. This makes it suitable for industrial sites where pressure and flow rates are constantly changing. This expands the application range of particle counters, enabling the counter to adaptively detect particle size even under fluctuating flow conditions.

[0026] 2. This particle counter relies on the dynamic sampling of the fluid in the medium pipeline, reducing the accessories such as hydraulic valves or metering pumps, making the installation of this counter simpler and more convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is an overall structural diagram of the particle size counter provided in an embodiment of the present application;

[0028] Figure 2 Schematic diagram of the structure of the detection end of the housing provided in an embodiment of the present application;

[0029] Figure 3 Schematic diagram of a T-shaped sampling channel provided in an embodiment of the present application;

[0030] Figure 4 This is a schematic diagram of the connection between the particle counter provided in an embodiment of the present application and the medium pipeline;

[0031] Figure 5 Schematic diagram of the flow field of a T-shaped sampling channel provided in an embodiment of the present application;

[0032] Figure 6 is a diagram showing the relationship between the pressure difference and the flow rate of a T-shaped sampling channel provided in an embodiment of the present application;

[0033] Figure 7 Schematic diagram of a current integration circuit provided in an embodiment of the present application.

[0034] Throughout the drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0035] 1. Housing; 2. Sampling channel; 2.1. Capillary tube; 2.2. Branch tube; 3. Light source; 4. Transparent sheet; 5. Photoelectric sensor; 6. Analysis circuit board; 7. Pressure difference sensor; 8. Current integration circuit; 9. Bend; 10. Resistor; 11. Capacitor; 12. Switch. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0037] The following is combined with Figure 1-7 This application is described in further detail.

[0038] The embodiment of the present application discloses a flow-adaptive particle counter. Figure 1-4 The flow adaptive particle counter includes a housing 1, a light source 3, a light-transmitting sheet 4, a photoelectric sensor 5, an analysis circuit board 6, a pressure difference sensor 7 and a processor, wherein: the housing 1 has a sampling channel 2, the housing 1 is used to connect with the medium pipeline, when part of the fluid in the medium pipeline flows into the sampling channel 2 of the housing 1, the pressure difference generated in the sampling channel 2 It is linearly related to the medium flow Q in the sampling channel 2; the differential pressure sensor 7 is used to measure the pressure difference between the two ends of the sampling channel 2. , and output in real time with the pressure difference The current I is linearly related, and the current I is accumulated and converted into a voltage U by the current integration circuit 8 in the analysis circuit board 6; the light source 3 and the photoelectric sensor 5 are arranged on both sides of the sampling channel 2 opposite to each other, and the light-transmitting sheet 4 is used to separate the light source 3, the photoelectric sensor 5 and the sampling channel 2. The light emitted by the light source 3 passes through the light-transmitting sheet 4 and the sampling channel 2 and then illuminates the photoelectric sensor 5. The photoelectric sensor 5 forms a voltage pulse based on the projection of the particles in the light; the processor is used to determine the particle size based on the number N of voltage pulses and the voltage U within the sampling period T.

[0039] Further, such as Figure 2-3As shown, the sampling channel 2 in the housing 1 is a T-shaped channel, primarily comprising a capillary tube 2.1 and multiple branch tubes 2.2. Capillary tube 2.1 is positioned at the axial center of the housing 1, its length aligned with the axial direction of the housing 1. One end of capillary tube 2.1 serves as the medium inlet, which is chamfered. The other end of capillary tube 2.1 is radially connected to a branch tube 2.2. Preferably, there are multiple branch tubes 2.2, extending radially in a straight line to the outer surface of the detection end of the housing 1.

[0040] Preferably, six branch pipes 2.2 are provided, and the diameter of the branch pipe 2.2 is 2.5-3.5 times the diameter of the capillary tube 2.1. The diameter of the capillary tube 2.1 requires that within the measured sampling flow range, the Reynolds number of the oil in the capillary tube 2.1 is Re≤500.

[0041] Further, such as Figure 4 As shown, the housing 1 of the particle counter is preferably mounted at a bend 9 in the media pipeline. Furthermore, preferably, the peripheral wall of the detection end of the housing 1 abuts against an inner wall of the bend 9. A detachable connection is employed between the housing 1 and the media pipeline. For example, the housing 1 may have a threaded structure on its peripheral side. After a threaded hole is formed at the upper end of the bend 9 in the media pipeline, the housing 1 is threadedly connected to the media pipeline.

[0042] When the shell 1 is installed at the bend 9 of the medium pipeline, the detection end of the shell 1 carries the sampling channel 2 and extends into the interior of the medium pipeline. A gap is left between the detection end of the shell 1 and the inner wall of the medium pipeline for the medium to pass through; the medium inlet of the capillary tube 2.1 is facing the liquid inlet of the bend 9, and the medium outlet of some branch pipes 2.2 is facing the liquid outlet of the bend 9; when the fluid flows through the bend 9 of the medium pipeline, in the channel of the bend 9, part of the fluid will flow through the sampling channel 2 in the shell 1, so that the particle size counter can rely on the power of the fluid in the medium pipeline to perform sampling.

[0043] Further, such as Figure 5-6 As shown, in this embodiment, the capillary tube 2.1 is a straight tube that is thick in the middle and thin at both ends, the middle section is a square tube, and the sections at both ends are round tubes. The fluid (oil) in the capillary tube 2.1 is in a laminar flow state.

[0044] Further, such as Figure 1As shown, the housing 1 also has a mounting slot intersecting the sampling channel 2 within the housing 1. Translucent sheets 4 are mounted at radial ends of the sampling channel 2, separating the sampling channel 2 from the mounting slot and preventing the fluid within the sampling channel 2 from flowing toward the light source 3, photoelectric sensor 5, and analysis circuit board 6. The translucent sheets 4 are preferably lenses. The light source 3 and photoelectric sensor 5 are positioned opposite each other within the mounting slot. The light source 3 is preferably a laser tube, and the photoelectric sensor 5 is preferably a photoelectric tube. During operation, laser light passes through the lenses, passes through the fluid (e.g., oil) within the sampling channel 2, and then is directed toward the photoelectric tube. As the liquid within the sampling channel 2 flows, particles block the laser light, projecting it onto the photoelectric tube, generating voltage pulses.

[0045] Furthermore, the light source 3 and photoelectric sensor 5 can be located on either side of the capillary tube 2.1 or on either side of the branch tube 2.2. More preferably, the light source 3 and photoelectric sensor 5 are located within the square tube of the capillary tube 2.1, or are located at both ends of the square tube. More preferably, one detection end of the differential pressure sensor 7 is located at the medium inlet of the capillary tube 2.1, and the other detection end is located at the medium outlet of the branch tube 2.2, thereby detecting the differential pressure between the two ends through the flow of the fluid.

[0046] Generally speaking, based on the above sampling channel 2, the pressure difference of the oil flowing through the liquid flow channel and liquid flow rate Into a linear relationship:

[0047] ,

[0048] in, is the pressure difference The relationship coefficient with the medium flow rate Q, the unit of medium flow rate Q is mL / min.

[0049] The pressure difference sensor 7 outputs current, and the real-time current I is proportional to the real-time pressure difference.

[0050] ,

[0051] is the real-time current I and voltage difference The unit of current I is mA.

[0052] When the system pressure in which the particle counter is located fluctuates, the sampling flow of the particle counter fluctuates continuously, so the current I of the differential pressure sensor 7 also changes continuously.

[0053] The changing current I of the differential pressure sensor 7 is accumulated into a voltage U through the current integrating circuit 8 .

[0054] ,

[0055] Wherein, C is the capacitance value in the current integration circuit 8, the unit is mF, the unit of voltage is V, the unit of current I is mA, and t represents the time variable.

[0056] like Figure 7 As shown, current integration circuit 8 includes a resistor 10, a capacitor 11, and a switch 12. Resistor 10, capacitor 11, and differential pressure sensor 7 form a series circuit, with switch 12 connected in parallel with capacitor 10. Capacitor 10 has detection endpoints connected to both ends for measuring the voltage U across capacitor 10. Before measurement, the switch is closed, discharging capacitor 10. Once the measured voltage U across the capacitors reaches zero, the switch is opened, and particle counting begins.

[0057] After a sampling period T, the voltage U across the capacitor in the current integration circuit 8 is measured, and the total sampling flow rate within the particle sampling period T is counted:

[0058] .

[0059] The processor is electrically connected to the photoelectric sensor 5, the pressure difference sensor 7, the analysis circuit board 6 and other components. The processor has the function of exchanging and processing information with each component. For example, the processor can record the number of voltage pulses generated by the photoelectric sensor 5 and obtain the number N of voltage pulses within the sampling period T. The processor is preferably a single-chip microcomputer (not shown in the figure). Its information exchange and information processing functions are all existing technologies and will not be described in detail here. When performing oil particle size detection, the number of particles n within the sampling period T and the total fluid sampling volume are used to obtain the number of voltage pulses N within the sampling period T. Dividing by , we can get the medium particle size. The number of particles n is the number of voltage pulses N detected within the sampling period T. After conversion, the obtained particle size is determined by the number of voltage pulses N within the sampling period T and the voltage U. The specific particle size c is calculated using the following formula:

[0060] .

[0061] In practice, due to the deviations that may be caused by actual processing technology and actual measurement, the pressure difference and liquid flow rate There may also be a relationship deviation A. This deviation A is usually obtained by actual measurement and fitting. +A.

[0062] For example, in some embodiments, the capillary tube 2.1 is formed of straight tubes with a diameter of 1 mm and a length of 5-10 mm at both ends, and a square tube with a size of 1.4 mm x 1.4 mm in the middle, and the length of the square tube is 5 mm. When the capillary tube 2.1 adopts this design, when the liquid flows through the straight tube, the pressure and flow rate are basically linearly related, as shown in the following example: Figure 6 As shown. Figure 6 In the relationship diagram shown, R 2 is the mean square error of the curve fitting. R 2 On a scale between 0 and 1, the closer it is to 1, the more accurately the fitted function expresses the relationship between the data points. For the T-shaped flow channel in this design, the mean square error of the fitted function for the pressure and flow data points in the function y = 484.9x - 771.9 is 0.999, indicating a linear relationship between the pressure and flow rates. The -771.9 in the function is the deviation A.

[0063] In some embodiments, the differential pressure sensor 7 is built with a test circuit for detecting whether the differential pressure sensor 7 is faulty. The differential pressure sensor 7 can emit a test current I through the test circuit. 检 Therefore, even if the measured pressure difference is 0Pa, the sensor will output a test current (such as I 检 =4mA). If the sensor output is 0, it means that the sensor has failed. When the differential pressure sensor 7 with a test circuit is current, the current also includes the detection current I 检 ,Right now: +I 检 .

[0064] For ease of understanding, for example, in some embodiments, when the capillary 2.1 adopts the above design, = , deviation A=-771.9, at this time the pressure difference of the oil flowing through the flow channel is: .

[0065] The differential pressure sensor 7 is selected to output 4-7mA current, and the real-time output current is related to the real-time differential pressure. is linearly related, where =0.32, test current I 检 The current is 4mA, and the current obtained is: .

[0066] After a particle sampling period T (i.e., counting period), the voltage U across the capacitor C is measured. The capacitance value of the capacitor C is selected as 10mF. The total sampling flow rate within the particle sampling period T is counted:

[0067] .

[0068] Then, the number of particles n in the sampling period T and the total sampling flow rate The granularity c is determined by the number N of voltage pulses and the voltage U within the sampling period T. The specific calculation formula is as follows:

[0069] .

[0070] It should be understood that expressions such as "include" and "may include" used in this application indicate the existence of the disclosed functions, operations, or constituent elements, and do not limit one or more additional functions, operations, and constituent elements. In this application, terms such as "include" and / or "have" may be interpreted as indicating a specific characteristic, number, operation, constituent element, component, or combination thereof, but may not be interpreted as excluding the existence or possibility of adding one or more other characteristics, numbers, operations, constituent elements, components, or combinations thereof.

[0071] It should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0072] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0073] In this application, unless otherwise specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they can refer to fixed connection, detachable connection, or integral connection; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0074] It is easy for those skilled in the art to understand that the above is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A flow-adaptive particle counter, characterized in that: The device comprises a housing (1), a light source (3), a light-transmitting sheet (4), a photoelectric sensor (5), an analysis circuit board (6), a pressure difference sensor (7) and a processor, wherein: The housing (1) has a sampling channel (2) therein, and the housing (1) is used to be connected to a medium pipeline. When the fluid in the medium pipeline flows through the sampling channel (2), the pressure difference generated in the sampling channel (2) It is linearly related to the medium flow rate Q; The differential pressure sensor (7) is used to measure the differential pressure at both ends of the sampling channel (2). , and output in real time with the pressure difference The current I is linearly related, and the current I is accumulated and converted into a voltage U by the current integration circuit (8) in the analysis circuit board (6); The light source (3) and the photoelectric sensor (5) are arranged opposite to each other on both sides of the sampling channel (2); the light-transmitting sheet (4) is used to separate the light source (3), the photoelectric sensor (5) and the sampling channel (2); the light emitted by the light source (3) passes through the light-transmitting sheet (4) and the sampling channel (2) and then irradiates the photoelectric sensor (5); the photoelectric sensor (5) forms a voltage pulse according to the projection of particles in the light; The processor is configured to determine the granularity based on the number N of voltage pulses and the voltage U within a sampling period T; The sampling channel (2) comprises a capillary tube (2.1), one end of the capillary tube (2.1) having a medium inlet, and the other end being radially connected to a branch tube (2.2); the capillary tube (2.1) is a straight tube that is thick in the middle and thin at both ends, and the middle tube section is a square tube, while the tube sections at both ends are circular tubes; the diameter of the branch tube (2.2) is 2.5-3.5 times the diameter of the capillary tube (2.1), and the Reynolds number Re of the fluid in the capillary tube (2.1) is ≤500; a plurality of branch tubes (2.2) are provided, and the plurality of branch tubes (2.2) are radially distributed at the ends of the capillary tube (2.1).

2. The flow-adaptive particle counter according to claim 1, wherein: The current integration circuit (8) comprises a resistor (10), a capacitor (11) and a switch (12); the resistor (10), the capacitor (11) and the pressure difference sensor (7) form a series loop; the switch (12) is connected in parallel with the capacitor (11).

3. The flow-adaptive particle counter according to claim 2, wherein: The accumulated voltage U within the sampling period T is calculated using the following formula: ， in, is the capacitance value in the current integration circuit (8), and t represents the time variable.

4. The flow-adaptive particle counter according to claim 2, wherein: The particle size The calculation is done using the following formula: ， Among them, K1 is the pressure difference Relationship coefficient with medium flow Q; is the current I and the voltage difference The relationship coefficient, is the capacitance value in the current integration circuit (8).

5. The flow-adaptive particle counter according to claim 1 or 2, characterized in that: The shell (1) is detachably connected to the bend (9) of the medium pipeline. After the detection end of the shell (1) is inserted into the medium pipeline, a gap is left between the detection end and the inner wall of the medium pipeline. The sampling channel (2) is located in the medium pipeline, and its medium inlet faces the liquid inlet of the bend (9).

6. The flow-adaptive particle counter according to claim 1 or 2, characterized in that: The differential pressure sensor (7) is built with a detection circuit for detecting whether the differential pressure sensor (7) is faulty.

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