Particulate matter collecting device, particulate matter measuring system, particulate matter collecting method and particulate matter measuring method

Abstract

The collection device (4) collects particulate matter (M) generated by frictional contact. The collection device (4) is provided with: a suction duct section (6) that sucks air containing particulate matter (M); a rectifying unit (7) that rectifies the air flow (F) within the suction duct unit (6) to a laminar flow state; an air discharge unit (9) that discharges the air sucked into the suction duct unit (6) to the outside of the suction duct unit (6); and a collection unit (8) that collects air flowing in a laminar flow state within the suction duct unit (6) within the suction duct unit (6).

Description

Technical Field

[0001] This invention relates to a device for collecting particulate matter generated by frictional contact, etc. Background Technology

[0002] In conventional methods for measuring brake wear (hereinafter referred to as Prior Art 1), the following method is often used: when collecting particles generated from the brake, a dust collection enclosure is installed around the entire brake unit, sampling air is introduced using a HEPA filter or the like, and the air containing particles is drawn in using a pipe (a constant volume sample collection device) or the like (for example, see Non-Patent Document 1). Additionally, in conventional methods for measuring brake wear (hereinafter referred to as Prior Art 2), the following method also exists: air containing particles is drawn into a pipe to cover only the brake section (for example, see Non-Patent Document 2).

[0003] A conventional brake dust measuring device (hereinafter referred to as Prior Art 3) includes: a housing surrounding a braking device; a supply pipe supplying air to the housing; an air discharge pipe discharging the air supplied to the housing through straight and curved pipes; and a particle measuring device collecting brake dust particles generated during brake operation within the air discharge pipe (see, for example, Patent Document 1). This conventional brake dust measuring device utilizes a fan system to supply air to the air supply pipe and uses an inlet filter to purify the air before supplying it.

[0004] Existing technical documents

[0005] Patent documents

[0006] Non-patent document 1: Hiroyuki Hagino, Motoaki Oyama, Sousuke Sasaki, "Laboratory testing of airborne brake wear particle emissions using adynamometer system under urban city driving cycles", Atmospheric Environment, 2016, 131, p.269~278

[0007] Non-patent document 2: Marcel Mathissen, Theodoros Grigoratos, Tero Lahde, Rainer Vogt, "Brake Wear Particle Emissions of a Passenger Car Measured on aChassis Dynamometer", Atmosphere, 2019, 10, 556

[0008] Patent Document 1: Japanese Patent Publication No. 2020-520448 Summary of the Invention

[0009] The problem the invention aims to solve

[0010] In existing technologies 1-3, quantitative measurement of the amount of particles discharged from the braking device requires full-volume suction, necessitating the use of a device that covers the entire source of the particles. However, this device is large in scale and incurs significant costs in its installation and operation. Furthermore, in existing technologies 1-3, the flow velocity distribution within the pipe may be unstable if there are bends. Moreover, while existing technologies 1-3 measure particles discharged from automobile braking devices, when measuring particles generated by frictional contact between the wheels of railway vehicles and the brake pads, the strong swirling wind generated by the high-speed rotation of the railway vehicle wheels causes particle dispersion, making measurement difficult.

[0011] In the dust collection devices commonly used in benchtop braking testing machines, the pipe diameter needs to be increased to ensure sufficient suction flow from the particle generation source to the pipe. As a result, the flow inside the pipe is unstable, and the flow velocity inside the pipe is inconsistent with the flow velocity inside the dust collector's collection tube, making it difficult to perform isokinetic suction.

[0012] The problem to be solved by the present invention is to provide a technology that can stably collect air containing particulate matter flowing in the suction pipe section from the collection unit.

[0013] Solution for solving the problem

[0014] The first technical solution is a particulate matter collection device that collects particulate matter generated due to frictional contact. The particulate matter collection device comprises: a suction pipe section that draws in air containing the particulate matter; a rectifier section that rectifies the airflow within the suction pipe section into a laminar flow state; an exhaust section that discharges the air drawn into the suction pipe section to the outside of the suction pipe section; and a collection section that collects the air flowing within the suction pipe section.

[0015] The second technical solution is based on the collection device of the first technical solution, wherein the collection device further comprises a dust collection section, which causes the heavier particulate matter in the particulate matter to fall down for dust collection, and the dust collection section discharges air containing the lighter particulate matter in the particulate matter to the suction pipe section.

[0016] The third technical solution is based on the collection device of the first or second technical solution, wherein the suction pipe section draws air containing the particulate matter in the direction of the wind generated by the movement of the friction contact member.

[0017] The fourth technical solution is a collection device according to any one of the first to third technical solutions, wherein the suction pipe section draws air containing the particulate matter from below to above.

[0018] The fifth technical solution is a collection device according to any one of the first to third technical solutions, wherein the suction pipe section draws air containing the particulate matter in a horizontal direction.

[0019] The sixth technical solution is based on the acquisition device of any one of the first to fifth technical solutions, wherein the total length of the straight pipe section of the suction pipe section is set as L, the inner diameter of the suction pipe section is set as D, the distance from the inlet of the suction pipe section to the acquisition port of the acquisition section is 0.4L to 0.8L, the inner diameter of the rectifier grid of the rectifier section is 0.02D to 0.10D, and the length of the rectifier grid is 0.5D to 1.0D.

[0020] The seventh technical solution is a measurement system, wherein the measurement system includes a collection device according to any one of the first to sixth technical solutions, and measures the particulate matter collected by the collection device.

[0021] The eighth technical solution is a collection method for collecting particulate matter generated due to frictional contact. This collection method includes the following steps: rectifying the airflow within a suction pipe section to make the airflow containing the particulate matter into a laminar flow state; discharging the air drawn into the suction pipe section to the outside of the suction pipe section; and collecting the airflow flowing within the suction pipe section.

[0022] The ninth technical solution is a measurement method, wherein the measurement method includes the collection method of the eighth technical solution, and the particulate matter collected using the collection method is measured.

[0023] The effects of the invention

[0024] According to the present invention, it is possible to stably collect air containing particulate matter flowing within the suction pipe section from the collection section. Attached Figure Description

[0025] Figure 1 This is a schematic diagram showing the overall structure of the measurement system of the first embodiment, and a schematic longitudinal sectional view showing the data acquisition device.

[0026] Figure 2 It is along Figure 1 A sectional view taken along line II-II.

[0027] Figure 3 It is along Figure 1 A sectional view taken along line III-III.

[0028] Figure 4A This is a cross-sectional view schematically showing a circular rectifier grid as the rectifier section of the particulate matter collection device of the first embodiment.

[0029] Figure 4B This is a cross-sectional view schematically showing the rectifier grid of the honeycomb core as the rectifier section of the particulate matter collection device of the first embodiment.

[0030] Figure 4C This is a cross-sectional view schematically showing a quadrilateral rectifier grid as the rectifier section of the particulate matter collection device of the first embodiment.

[0031] Figure 5 It is an enlarged representation Figure 1 A sectional view of the V-section.

[0032] Figure 6 This is a schematic diagram showing the dimensions of various parts of the particulate matter collection device according to the first embodiment.

[0033] Figure 7A This is a schematic diagram of the particulate matter collection device used to illustrate the effect of the device in the first embodiment.

[0034] Figure 7B This is a schematic diagram of a comparative example collection device used to illustrate the effect of the particulate matter collection device of the first embodiment.

[0035] Figure 8 This is a schematic longitudinal sectional view of the particulate matter collection device according to the second embodiment.

[0036] Figure 9AThis is a graph showing the measurement results of the particulate matter collected by the particulate matter collection device of the embodiment using a particulate measuring device, and it is a graph showing the measurement results when the initial speed of the wheel is 65 [km / h].

[0037] Figure 9B This is a graph showing the measurement results of particulate matter collected by the particulate matter collection device of the embodiment using a particulate measuring device, and it is a graph showing the measurement results when the initial speed of the wheel is 95 [km / h].

[0038] Figure 10 This is a schematic diagram of a modified version of the data acquisition device.

[0039] Figure 11 This is a schematic diagram of a modified version of the data acquisition device. Detailed Implementation

[0040] (First Embodiment)

[0041] Hereinafter, the first embodiment will be described in detail with reference to the accompanying drawings.

[0042] Figure 1 This diagram schematically illustrates the overall structure of a measurement system for measuring particulate matter during the braking action of wheel 1 and braking device 2, the objects of measurement. The data collection device 4 is shown in a schematic longitudinal sectional view. Figure 1 In this system, the measuring system consists of devices other than the wheel 1 and the braking device 2, which are the objects of measurement, and is configured to include a collection device 4 and a particle measuring device 11. Figure 1 The wheel 1 shown is a component that makes rolling contact with the track. For example... Figure 2As shown, wheel 1 has a tread surface 1a that contacts the top surface of the track to withstand frictional resistance, and a flange surface 1b that is continuously formed with the outer periphery of wheel 1 to prevent derailment. Wheel 1 is a component of the wheel axle supporting a railway vehicle, and is the wheel used in actual railway vehicles. Wheel 1 is either a one-piece rolled wheel in which the wheel rim and wheel core are integrally rolled from high carbon steel, or a wheel with a wheel rim formed by hot-fitting the wheel rim to the wheel core. Here, one-piece rolled wheels are, for example, AR (as rolled) wheels that have not undergone heat treatment, SQ (slackquenched) wheels used in trams or pneumatic vehicles where the surface area has a fine pearlitic structure to prevent hot cracking, and RQ (rim quenched) wheels used in trams or Shinkansen (registered trademark) trams where the surface area has a tempered martensitic structure to increase strength. Wheels with wheel rims are, for example, wheels with a rolled wheel core made of high carbon steel, or cast steel wheels made of cast steel. Wheel 1 is mounted on a braking performance testing machine, which can control braking pressure, deceleration and torque under a wide range of conditions, from locomotives to commuter trains and equivalent to the Shinkansen, and can conduct tests equivalent to actual driving.

[0043] Figure 1 and Figure 2 The braking device 2 shown is a device for enabling braking. Braking device 2 is a basic braking device that generates friction by mechanically actuating air or hydraulic pressure specified by the brake control device flowing into the brake cylinder via a lever mechanism or similar mechanism. Braking device 2 is a tread brake device that generates braking force by pressing the brake block 3 against the tread surface 1a of the wheel 1, thus generating friction. Figure 1 and Figure 2 The braking device 2 shown is, for example, a unit brake in which each component is modularized, and is a one-sided pressing brake block brake in which the brake block 3 is pressed against the tread surface 1a of the wheel 1 from one side of the wheel 1. The braking device 2 is installed on a braking performance testing machine for evaluating the performance of tread brakes, and is a braking device used on actual railway vehicles. The braking device 2 includes the brake block 3.

[0044] Brake block 3 is a component that generates friction by being pressed against the tread surface 1a of wheel 1. For example... Figure 1 As shown, the brake block 3 is a brake friction element (brake shoe) with an arc-shaped appearance, and its back side is held by the brake block head (mounting part (brake shoe head)). The brake block 3 has a friction surface (lining surface) 3a that frictionally contacts the tread surface 1a. Figure 1 and Figure 2 As shown by the solid line, the brake block 3 moves towards the tread surface 1a of the wheel 1 during braking and is pressed against the tread surface 1a. Figure 1 and Figure 2As shown by the double-dotted line, brake block 3 retracts from the tread surface 1a of wheel 1 and separates from tread surface 1a when braking is released. Brake block 3 can be, for example, a synthetic brake block made primarily of synthetic resin; a conventional cast iron brake block made primarily of ordinary cast iron composed of flake graphite and pearlite; an alloy cast iron brake block made by adding a certain amount or more of special elements such as phosphorus and chromium to a conventional cast iron brake block base; a high-phosphorus cast iron brake block with increased phosphorus content in its alloy cast iron formulation; or a sintered alloy brake block made by adding various metal powders such as iron and copper, as well as graphite powder, and then firing and pressing it. Brake block 3 is the same type of brake block used in railway vehicles as wheel 1.

[0045] Figure 1 The collection device 4 shown is a device for collecting particulate matter M generated due to frictional contact. For example... Figure 2 and Figures 4A to 4C As shown, the collection device 4 ensures that the flow velocity distribution of the fluid F, which contains particulate matter M generated by the frictional contact between the wheel 1 and the brake block 3, is approximately uniform. Figure 1 As shown, the collection device 4 is a small, vertical dust collection device that extends in the vertical direction, guiding the fluid F from bottom to top. It is easily installed and removed compared to existing devices such as brake performance testing machines. The collection device 4 has... Figure 1 and Figure 2 Dust collection section 5 shown Figures 1-3 and Figure 5 The suction pipe section 6 shown Figure 1 and Figure 3 The rectifier section 7 shown is shown. Figure 1 and Figure 5 The collection unit 8 shown Figure 1 The exhaust section 9 and the support section 10 are shown. The collection device 4 ensures the suction flow rate of the air drawn into the suction pipe section 6, and draws the air in the suction pipe section 6 into the collection section 8 at a speed equal to the air flow velocity in the suction pipe section 6 to collect particulate matter M. Figure 1 and Figure 5 As shown, the collection device 4 draws air from the collection section 8 at a velocity approximately the same as the air flow F in the suction pipe section 6 by making the air flow F in the suction pipe section 6 roughly uniform.

[0046] Figure 1 and Figure 5The particulate matter M shown is generated due to frictional contact. Particulate matter M is primarily generated as wear on the brake pad 3 due to frictional contact between the wheel 1 and the brake pad 3. Particulate matter M can be micron-sized solid particles, suspended particulate matter, dust, wear powder, or wear fragments, etc. Suspended particulate matter includes, for example, substances with a particle size of 10 μm or less, such as PM10 with a particle size of approximately 10 μm or less, PM2.5 (micro-particulate matter) with a particle size of approximately 2.5 μm or less, or ultrafine particles with a particle size of approximately 0.1 μm or less. Dust includes, for example, fine, dust-like solid particles suspended in the gas, such as powder, and solid suspended matter with a particle size of less than 75 μm.

[0047] Figure 1 The dust collection unit 5 shown is for collecting the heavier particulate matter M2 from the particulate matter M. The dust collection unit 5 discharges air containing the lighter particulate matter M1 from the particulate matter M into the suction pipe unit 6. Here, the lighter particulate matter M1 is, for example, suspended particulate matter or dust. The heavier particulate matter M2 is, for example, abrasive powder or abrasive fragments. Figure 1 and Figure 2 As shown, the dust collection unit 5 is a shell component with a cuboid or cubic shape. The dust collection unit 5 houses the contact surface between the wheel 1 and the brake block 3, the brake block 3, and the area around the brake block head that holds the brake block 3. The dust collection unit 5 functions as a dust collection box for collecting relatively heavy particulate matter M2. Because the dust collection unit 5 forms a cavity (cavity), the airflow F within it becomes turbulent due to the rotating wind generated by the rotation of the wheel 1. Here, turbulence refers to a state where various fluid elements are mixed and the air flows irregularly. The dust collection unit 5 has... Figure 1 and Figure 2 The suction port 5a shown is Figure 1 The discharge outlet 5b is shown.

[0048] Figure 1 and Figure 2 The suction port 5a shown is the part that draws air from outside the dust collection section 5 into the dust collection section 5. The suction port 5a is opened on the side of the dust collection section 5 in such a way that a predetermined gap (e.g., about 10 mm) △ is formed between the suction port 5a and the wheel 1, so as to reduce the influence of the rotating wind generated as the wheel 1 rotates. Figure 1 The outlet 5b shown is the portion that discharges the airflow F containing particulate matter M. For example... Figure 1 and Figure 2 As shown, the outlet 5b is provided on the upper surface of the dust collection section 5 to discharge an airflow F containing particulate matter M from the dust collection section 5 toward the rectifier section 7. The dust collection section 5 is detachably mounted on the brake performance testing machine.

[0049] Figures 1-3 and Figure 5 The suction pipe section 6 shown is for drawing in air containing particulate matter M. The suction pipe section 6 draws in air containing particulate matter M in the direction of the rotating airflow generated by the rotation of the wheel 1 in frictional contact, and also draws in air containing particulate matter M from below to above. The suction pipe section 6 includes a straight pipe section 6A extending in the vertical direction and a bent pipe section (elbow) 6B that directs the fluid F flowing vertically within the straight pipe section 6A at a 90-degree angle in the horizontal direction. In the suction pipe section 6, the downstream end of the straight pipe section 6A is connected to the upstream end of the bent pipe section 6B. The suction pipe section 6 functions as a guide pipe that directs air from the dust collection section 5 to the exhaust section 9. Figure 2 and Figure 3 As shown, the suction pipe section 6 is a flow path with a circular cross-section, and is a circular pipe made of transparent or semi-transparent synthetic resin. Figure 1 As shown, the suction pipe section 6 has an inlet 6a and an outlet 6b. The inlet 6a is the portion for air to flow into the dust collection section 5. The inlet 6a is formed at the lower end of the suction pipe section 6 and is connected to the outlet 5b of the dust collection section 5. The outlet 6b is the portion for air to flow out of the suction pipe section 6. The outlet 6b is formed at the upper end of the suction pipe section 6. The inner diameter of the suction pipe section 6 is constant from the inlet 6a on the upstream side to the outlet 6b on the downstream side.

[0050] Figure 1 and Figure 3 The rectifier 7 shown is the part that rectifies the airflow F within the suction pipe section 6 into a laminar flow state. The rectifier 7 rectifies the airflow F within the suction pipe section 6 into a laminar flow state so that the collecting unit 8 can collect the air flowing in a laminar flow state within the suction pipe section 6. Here, as... Figure 1 and Figure 5 As shown, laminar flow refers to a state where fluid elements flow in a regular, linear fashion along the direction of fluid F, meaning the streamlines of fluid F are always parallel to the pipe axis. The rectifier 7 adjusts the turbulent airflow F flowing into the suction pipe section 6 into a unidirectional airflow F by allowing it to pass through. The rectifier 7 generates a fluid (Hagen-Poiseuille flow) F within the suction pipe section 6 with a velocity distribution that is symmetrical with respect to the centerline of the straight pipe section 6A: the velocity decreases closer to the inner wall of the suction pipe section 6, reaches zero at the inner wall, and is greatest at the center of the suction pipe section 6. Figure 1 and Figure 5In order to conceptually represent the velocity distribution of an airflow rectified into a laminar flow state, a line is shown consisting of multiple arrows of length corresponding to the velocity arranged in parallel and connected in a mountain-shaped pattern at their apexes. The rectifier 7 is positioned upstream of the collection unit 8 and close to the inlet 6a of the suction pipe unit 6. The rectifier 7 includes... Figure 1 , Figure 3 and Figures 4A to 4C The rectifier grille 7a is shown.

[0051] Figure 1 , Figure 3 and Figures 4A to 4C The flow straightener 7a shown is a component that divides the suction pipe section 6 into multiple sections to adjust the airflow F within the suction pipe section 6. As the flow straightener 7a, multiple thin tubes of predetermined length and inner diameter are arranged radially in a grid pattern without gaps within the suction pipe section 6. The flow straightener 7a is as follows... Figure 3 and Figure 4A The cross-sectional shape shown is a circular tube, such as... Figure 4B The cross-sectional shape shown is a hexagonal honeycomb structure, i.e., a honeycomb core. Figure 4C The cross-sectional shape shown is a square tube with a quadrilateral shape.

[0052] Figure 1 and Figure 5 The collection section 8 shown is the part that collects air flowing within the suction pipe section 6. The collection section 8 collects air flowing in a laminar flow state within the suction pipe section 6. The collection section 8 has a collection port 8a at its front end for drawing in and collecting air from within the suction pipe section 6. The collection section 8 is a thin tubular probe (collection tube) inserted into the suction pipe section 6. The collection section 8 passes through the bend 6B of the suction pipe section 6 and guides the air containing particulate matter M drawn from the collection port 8a to the measuring section 11b of the particle measuring device 11. The collection section 8 draws air from the suction pipe section 6 into itself at a flow rate equal to or slightly faster than the flow rate of the air flowing within the suction pipe section 6. The portion of the collection section 8 inserted into the suction pipe section 6 is arranged parallel to the inner wall of the suction pipe section 6, with the collection port 8a located on the centerline of the straight section 6A of the suction pipe section 6.

[0053] Figure 1The exhaust section 9 shown is a portion that discharges air from the suction pipe section 6 to the outside of the suction pipe section 6 while maintaining a laminar flow state of the airflow F within the suction pipe section 6. The exhaust section 9 draws air from the suction pipe section 6 and discharges it from within the suction pipe section 6 to avoid creating swirling flow within the suction pipe section 6. The exhaust section 9 includes: an intake port 9a connected to the outlet port 6b of the suction pipe section 6 for drawing in air; a cylindrical rotating body 9b that rotates; a housing 9c that covers the rotating body 9b to allow it to rotate freely; a motor 9d that drives the rotating body 9b to rotate; multiple blades 9e that protrude from the outer circumferential surface of the rotating body 9b at intervals; and an outlet 9f for expelling the air drawn in from the intake port 9a. The exhaust section 9 is, for example, a multi-bladed blower such as a multi-bladed fan. The exhaust unit 9 uses a centrifugal blower that draws in air from the suction pipe section 6 through the intake port 9a and blows the air out of the outlet 9f in a centrifugal direction as an exhaust fan to discharge air from the suction pipe section 6. In order to suppress the discharge of particulate matter M from between the wheel 1 and the suction port 5a of the dust collection unit 5, the exhaust unit 9 draws air from the dust collection unit 5 and the suction pipe section 6 in a manner that creates a negative pressure in the dust collection unit 5, and exhausts the air in a direction perpendicular to the rotation axis of the exhaust unit 9.

[0054] The support part 10 supports the exhaust part 9. The support part 10 is a metal frame-shaped component, such as an aluminum frame, and is arranged parallel to the suction pipe part 6. In the support part 10, the upper end of the support part 10 supports the exhaust part 9, and the lower end of the support part 10 is detachably mounted on the brake performance testing machine.

[0055] The particle measuring device 11 is an apparatus for measuring particulate matter M flowing within the suction pipe section 6. The particle measuring device 11 draws in air containing particulate matter M flowing within the suction pipe section 6 and measures the particulate matter M flowing within the suction pipe section 6. The particle measuring device 11 measures, for example, number concentration and particle size distribution. Number concentration represents the number of particulate matter M per unit volume in the gas, and particle size distribution is a histogram with the size of the particulate matter M on the horizontal axis and frequency on the vertical axis. The particle measuring device 11 internally includes a filter section that allows only particulate matter M within the particle size range of the object being measured to pass through. Figure 1As shown, the particulate measuring device 11 includes a connecting part 11a, a measuring part 11b, a filtering part 11c, and a suction part 11d. The connecting part 11a connects to the rear end of the collecting part 8. The connecting part 11a introduces air containing particulate matter M flowing within the collecting part 8 into the measuring part 11b. The measuring part 11b measures the number concentration and particle size distribution of particulate matter M. For example, the measuring part 11b measures suspended particulate matter such as PM10, PM2.5, or ultrafine particles with a particle size of 10 μm or less. The measuring part 11b measures the number concentration and particle size distribution of particulate matter M based on the principle that the amount of scattered light generated by particulate matter M contained in the air drawn from the collecting part 8 varies proportionally to the mass of the particulate matter M. The filtering part 11c removes particulate matter M. The filtering part 11c removes particulate matter M from the air flowing into the measuring part 11b and discharges the removed air into the suction part 11d. The suction unit 11d is a section that draws air flowing within the suction pipe section 6 to the measuring unit 11b via the collecting unit 8. The suction unit 11d draws air from the suction pipe section 6 into the collecting unit 8 at a constant flow rate, with the air flowing within the collecting unit 8 having a flow rate equal to or slightly faster than the air flowing within the suction pipe section 6. The suction unit 11d is a pump or similar device used to draw a small amount of air from the air flowing within the suction pipe section 6 into the collecting unit 8 at a constant flow rate.

[0056] Figure 1 The flow rate measuring device 12 shown is used to measure the flow rate of air flowing within the suction pipe section 6. The flow rate measuring device 12 includes a hot wire section (probe) 12a and a measuring section 12b. The hot wire section 12a is the part that receives the airflow F within the suction pipe section 6. The hot wire section 12a is a heated metal wire inserted into the straight tube section 6A of the suction pipe section 6. The measuring section 12b is the part that measures the flow rate of the air flowing within the suction pipe section 6. The measuring section 12b measures the flow rate of the air flowing within the suction pipe section 6 by utilizing the phenomenon that the heat transferred from the hot wire section 12a to the surrounding air depends on the air velocity. The measuring section 12b measures the flow rate based on the change in resistance value generated when the hot wire section 12a receives the airflow F and undergoes a temperature change.

[0057] Next, the optimal range of the dimensions of each part of the particulate matter collection device of the first embodiment will be explained.

[0058] like Figure 6 As shown, if the total length of the straight pipe section 6A of the suction pipe section 6 is set as L, and the inner diameter of the suction pipe section 6 is set as D, then the distance L from the inlet 6a of the suction pipe section 6 to the collection port 8a of the collection section 8 is... PThe flow rate is 0.4L to 0.8L, the inner diameter d of the rectifier grille 7a of the rectifier section 7 is 0.02D to 0.10D, and the length l of the rectifier grille 7a is 0.5D to 1.0D. Here, in... Figure 4B The situation of the honeycomb core shown and Figure 4C In the case of the quadrilateral shown, the inner diameter d of the rectifier grille 7a is the diameter of the inscribed circle that contacts its inner surface.

[0059] Next, the function of the particulate matter collection device of the first embodiment will be explained.

[0060] In order to utilize Figure 1 and Figure 5 For the particle measuring device 11 shown to stably measure particulate matter M, the flow velocity of the air flowing within the suction pipe section 6 needs to be consistent with the flow velocity of the air drawn from the suction pipe section 6 into the collection section 8 and flowing within the collection section 8. For this purpose, it is necessary to ensure a uniform flow velocity distribution of the air flowing within the suction pipe section 6, and to ensure that the airflow F within the suction pipe section 6 is in a laminar flow state. In the first embodiment, as... Figure 1 As shown, the exhaust section 9 draws air from the suction pipe section 6 to prevent the airflow F in the suction pipe section 6 from swirling, and the rectifier section 7 rectifies the airflow F flowing in the suction pipe section 6.

[0061] Figure 7B The acquisition device 104 shown is Figure 7A The collection device 4 shown is different from the one shown. It does not have a rectifier 7. Instead, it uses an air supply section 109, which is different from the exhaust section 9, to supply air from the bottom of the dust collection section 105 into the dust collection section 105 and the air supply duct section 106. Figure 7A , Figure 7B The origin O shown is the center of the lower ends of the suction duct section 6 and the air supply duct section 106, and x is the position where the parts separate upwards from the origin O. The flow rate Q(x) [m] at position x is... 3 / s] is represented by the following mathematical expression 1.

[0062] [Mathematical Formula 1]

[0063]

[0064] Here, ρ, as shown in Equation 1, is the density of air [kg / m³]. 3 μ is the viscosity coefficient of air, D is the inner diameter of the suction pipe section 6 and the air supply pipe section 106 [mm], and dP / dx is the pressure gradient representing the rate of change of pressure P between the origin O and position x in the suction pipe section 6 and the air supply pipe section 106.

[0065] exist Figure 7BIn the sampling device 104 shown, the airflow F within the air supply duct section 106 becomes turbulent, and the pressure gradient dP / dx within the air supply duct section 106, as shown in Equation 1, is greater than 0 (becoming a positive pressure gradient). This causes detachment and backflow at the boundary layer of the wall within the air supply duct section 106, resulting in turbulent migration. Consequently, the velocity distribution within the air supply duct section 106 becomes uneven, and the velocity of the air flowing within the air supply duct section 106 changes. On the other hand, in Figure 7A In the sampling device 4 shown, the exhaust section 9 draws air from the suction pipe section 6 to prevent swirling flow within the suction pipe section 6, and the rectifier section 7 rectifies the air flowing within the suction pipe section 6. Therefore, the airflow F passing through the rectifier section 7 within the suction pipe section 6 becomes laminar, and the pressure gradient dP / dx within the suction pipe section 6, as shown in Equation 1, is ≤0 (becoming a negative pressure gradient). Consequently, no peeling or backflow occurs at the wall boundary layer within the suction pipe section 6. As a result, the air velocity flowing within the suction pipe section 6 is approximately the same as the air velocity flowing within the sampling section 8, and the particle measuring device 11 accurately measures the uniformly dispersed particulate matter M within the suction pipe section 6.

[0066] Next, the method for collecting and measuring particulate matter according to the first embodiment will be described.

[0067] like Figure 1 When the exhaust unit 9 is activated, it draws air from the dust collection unit 5 and the suction pipe 6, creating a negative pressure within both sections. If the brake performance testing machine starts operating and the wheel 1 begins to rotate, a rotating airflow is generated in the direction of wheel 1's rotation. Consequently, air is drawn into the dust collection unit 5 through the gap Δ between the wheel 1 and the suction port 5a, and the air flows from the dust collection unit 5 towards the suction pipe 6.

[0068] If braking device 2 performs braking action based on the braking command output by the braking performance testing machine, then as follows Figure 1 and Figure 2 As shown by the solid line, the friction surface 3a of the brake block 3 is in close contact with the tread surface 1a of the wheel 1. The result is as follows: Figure 1 As shown, the braking force is applied to the wheel 1 due to the friction between the tread surface 1a and the friction surface 3a, and particulate matter M is generated due to the frictional contact between the wheel 1 and the brake block 3. At this time, since there is a negative pressure inside the dust collection section 5, the particulate matter M is prevented from flowing out of the dust collection section 5 from the suction port 5a of the dust collection section 5 and the gap Δ between the wheel 1 and the brake block 3.

[0069] The rotating airflow generated by the rotation of wheel 1 causes the fluid F within the dust collection section 5 to become turbulent, resulting in a violent mixing of lighter particulate matter M1 and heavier particulate matter M2. Most of the heavier particulate matter M2 falls to the bottom of the dust collection section 5, while some of the heavier particulate matter M2 flows together with the lighter particulate matter M1 from the outlet 5b of the dust collection section 5 into the suction pipe section 6. However, some of the heavier particulate matter M2 flowing into the suction pipe section 6 falls back into the dust collection section 5 due to its own weight.

[0070] like Figure 1 As shown, since an exhaust section 9 is arranged on the downstream side of the suction pipe section 6, air is drawn into the suction pipe section 6 using the exhaust section 9 to avoid swirling flow in the suction pipe section 6. Furthermore, since a rectifier section 7 is arranged on the upstream side of the suction pipe section 6, the airflow F flowing into the suction pipe section 6 from the dust collection section 5 is adjusted. Therefore, as... Figure 1 and Figure 5 As shown, there is no stripping of airflow F from the wall inside the suction pipe section 6, the velocity distribution of airflow F inside the suction pipe section 6 is approximately uniform, and the airflow F downstream of the rectifier section 7 inside the suction pipe section 6 is in a laminar flow state. The exhaust section 9 draws in air in a state where particulate matter M is uniformly dispersed inside the suction pipe section 6 at a predetermined suction flow rate, so that the velocity of the air flowing inside the suction pipe section 6 is approximately the same as the velocity of the air drawn by the collection section 8 and flowing inside the collection section 8.

[0071] As a result, particulate matter M that has passed through the rectifying section 7 is drawn from the collection section 8 to the measuring section 11b of the particle measuring device 11 at a flow rate approximately the same as the airflow velocity within the suction pipe section 6. The number concentration and particle size distribution of the particulate matter M are then measured by the measuring section 11b. Since the exhaust section 9 draws air from the suction pipe section 6 to avoid generating swirling flow within the suction pipe section 6, the airflow F within the suction pipe section 6 remains in a laminar flow state, and the exhaust section 9 discharges the air from the suction pipe section 6 to the outside of the suction pipe section 6.

[0072] According to the first embodiment, the following effects are achieved.

[0073] (1) In the first embodiment, the suction pipe section 6 draws in air containing particulate matter M, the rectifier section 7 rectifies the airflow F within the suction pipe section 6 into a laminar flow state, and the exhaust section 9 discharges the air drawn into the suction pipe section 6 to the outside of the suction pipe section 6 to maintain the laminar flow state of the airflow F within the suction pipe section 6. The collection section 8 collects the air flowing in a laminar flow state within the suction pipe section 6. Therefore, the velocity distribution of the airflow F around the collection port 8a of the collection section 8 within the suction pipe section 6 is approximately uniform, which can suppress the velocity variation of the airflow F within the suction pipe section 6 and stabilize the velocity distribution of the airflow F within the suction pipe section 6. As a result, the velocity of the air flowing within the suction pipe section 6 can be made approximately the same as the velocity of the air flowing within the collection section 8, thus enabling the collection of air containing particulate matter M at a constant velocity and stably from the collection section 8. Furthermore, by utilizing the exhaust section 9 to draw air from the dust collection section 5 to the suction pipe section 6 without generating a swirling flow, air can also be drawn from the inner wall portion of the suction pipe section 6. As a result, fluctuations in the airflow velocity within the suction pipe section 6 can be suppressed, and the airflow velocity within the suction pipe section 6 can be stabilized, resulting in a roughly uniform velocity distribution within the suction pipe section 6. For example, by using a centrifugal fan such as a multi-bladed fan as the exhaust section 9, fluctuations in the airflow velocity within the suction pipe section 6 can be easily suppressed and the velocity stabilized by drawing air from the dust collection section 5 to the straight pipe section 6A of the suction pipe section 6.

[0074] (2) In the first embodiment, the heavier particulate matter M2 generated by frictional contact is allowed to fall and be collected by the dust collection unit 5, while the air containing the lighter particulate matter M1 generated by frictional contact is discharged into the suction pipe section 6. Therefore, the heavier particulate matter M2 can fall due to its own weight and be collected by the dust collection unit 5, the airflow F containing the lighter particulate matter M1 can be rectified by the rectifier unit 7, and the particulate matter M that is uniformly dispersed in the suction pipe section 6 can be collected by the collection unit 8.

[0075] (3) In the first embodiment, the suction pipe section 6 draws air containing particulate matter M in the direction of the rotating wind generated by the movement of the wheel 1 in frictional contact. For example, when measuring particulate matter generated by frictional contact between the wheel rim and the road surface, the airflow containing particulate matter is guided laterally towards the measuring device from the cover covering the wheel rim and the road surface. Therefore, there is a problem that the direction of the tangential force acting on the contact surface between the wheel rim and the road surface is orthogonal to the direction of flow, and larger particulate matter falling to the bottom of the cover will be swept up by the rotating wind generated by the rotation of the wheel rim. In the first embodiment, the airflow generated by the rotation of the wheel 1 is along the tangential direction of the contact point where the wheel 1 contacts the brake block 3, and most of the particulate matter M generated by frictional contact is discharged in the tangential direction of the contact point. Therefore, it is possible to draw air into the suction pipe section 6 in such a way that the direction of the rotating wind generated by the rotation of the wheel 1 is consistent with the direction of the fluid F in the suction pipe section 6 and to rectify the fluid F using the rectifying section 7. In addition, it can prevent the rotating air from blowing towards the bottom of the dust collection section 5, thus preventing the heavier particulate matter M2 that falls to the bottom of the dust collection section 5 from being rolled up.

[0076] (4) In the first embodiment, the suction pipe section 6 draws air containing particulate matter M from below to above. Therefore, heavier particulate matter M2, which is not a fine particle, such as abrasive powder or abrasive discs, can fall due to gravity and be collected in the dust collection section 5. Furthermore, since it is a vertical device extending vertically rather than a horizontal device as in the prior art 1-3, mobility is improved and installation is easy. Moreover, it is not necessary to use an air filter to pass the lighter particulate matter M1 through and remove the heavier particulate matter M2. Therefore, a simple structure can be used to separate the lighter particulate matter M1 from the heavier particulate matter M2, and the airflow velocity flowing in the suction pipe section 6 can be prevented from decreasing due to the air filter.

[0077] (Second Implementation)

[0078] The following is about... Figure 1 The parts shown in Figure 7 that are identical are labeled with the same reference numerals and detailed descriptions are omitted.

[0079] Figure 8The control device 13 shown is a device that controls the operation of the exhaust section 9 of the collection device 4 based on the measurement results of the flow velocity measuring device 12. The control device 13 controls the rotation of the motor 9d of the exhaust section 9 in a manner that makes the flow velocity of the air flowing in the suction pipe section 6 a predetermined flow velocity, based on the output signal (flow velocity signal) output from the measuring section 12b of the flow velocity measuring device 12. For example, the control device 13 adjusts the rotational speed of the motor 9d to make the flow velocity of the air flowing in the suction pipe section 6 approximately the same as the flow velocity of the air flowing in the collection section 8, thereby adjusting the flow rate of the air drawn into the suction pipe section 6.

[0080] In addition to the effects of the first embodiment, the particulate matter collection device of the second embodiment also has the following effects.

[0081] In the second embodiment, the control device 13 controls the operation of the exhaust section 9 based on the measurement results of the flow rate measuring device 12. Therefore, for example, feedback control of the operation of the exhaust section 9 can be performed based on the measurement results of the airflow velocity flowing within the suction pipe section 6, suppressing fluctuations in the airflow velocity flowing within the suction pipe section 6. As a result, the airflow velocity distribution around the collection port 8a of the collection section 8 is approximately uniform, stabilizing the airflow velocity distribution within the suction pipe section 6.

[0082] Example

[0083] Next, specific embodiments will be described.

[0084] Will Figure 6 The data acquisition device 4 shown is installed on the brake performance testing machine of the Railway Technical Research Institute, a public interest incorporated foundation, and utilizes... Figure 1 The flow rate measuring device 12 shown measures the flow rate of air in the suction pipe section 6 when air is discharged from the suction pipe section 6 by the exhaust section 9. Additionally, as... Figure 1 and Figure 2 As shown, the particulate matter M generated when the brake block 3 is pressed against the wheel 1 was measured using the particulate measuring device 11. Figure 1 and Figure 2 The wheel 1 shown uses the original track wheel. The brake block 3 uses a physical composite brake block. Figure 1 , Figure 5 and Figure 6 The rectifier unit 7 shown is a rectifier unit that converts multiple rectifiers such as... Figure 4A The fluid shown is formed by bundling together commercially available straws with a circular cross-section and inserting them into the suction tube 6 to form a fluid. Figure 1 The exhaust unit 9 shown is an industrial blower with an air volume of 2.4 m³ / s. 3 The value was measured at [ / min].

[0085] Figure 9A , Figure 9B The graph shown is Figure 6 The measurement results of the particle measuring device 11 shown are as follows: Figure 9A The results were obtained when the initial speed of the wheel was 65 km / h. Figure 9B This is the result of the measurement when the initial speed of the wheel is 95 km / h. For example... Figure 1 and Figure 2 As shown, the particle measuring device 11 was used to measure the amount of particles (mg / m³) generated when the brake block 3 was pressed against the wheel 1 with a pressure of 10 kN upon receiving a braking command. 3 The result is as follows: Figure 9A , Figure 9B As shown, it was confirmed that the air velocity flowing in the suction pipe section 6 is approximately constant, and the velocity distribution in the suction pipe section 6 is also approximately constant, so the air flow F in the suction pipe section 6 can be rectified into a laminar flow state by the rectifier section 7.

[0086] Furthermore, it was confirmed that the ratio of kinetic energy at an initial velocity of 95 km / h to that at an initial velocity of 60 km / h is approximately 2.1 times. This is comparable to the particle size of 18.0 mg / m³ measured at an initial velocity of 95 km / h. 3 The particle quantity measured at an initial velocity of 60 km / h was 7.5 mg / m³. 3 The ratio of particle number to kinetic energy is approximately 2.4 times. Therefore, it is confirmed that if the rotational speed of wheel 1 increases and the kinetic energy increases, the particle quantity also increases. Even with the increased influence of the rotating wind accompanying the rotation of wheel 1 and the increased turbulence of the airflow in the dust collection section 5, the particle quantity can still be accurately measured.

[0087] Furthermore, it was confirmed that the dimensions of each part of the measuring device 4 were: total length L: 900 [mm], inner diameter D: 150 [mm], and distance L. P The dimensions of the data acquisition device 4 are within the optimal range for each part: 450 mm = 0.5L, inner diameter d: 6 mm = 0.04D, length l: 80 mm = 0.53D. Additionally, the flow rate of the multi-bladed fan is 2.4 m / s². 3 The theoretical value of the air velocity flowing in the suction pipe section 6 at [min] is 2.26 [m / s]. Figure 9A and Figure 9B The measured flow rate values ​​shown are roughly consistent with the theoretical values.

[0088] This invention is not limited to the embodiments described above, and various modifications or alterations can be made as described below, which are also within the scope of this invention.

[0089] (1) In the above embodiment, the braking device 2 of a railway vehicle was described as an example, but the present invention can also be applied to braking devices of other transportation units such as automobiles, motorized two-wheelers, or bicycles. In addition, in the above embodiment, the case where the braking device 2 is a tread brake device was described as an example, but the present invention can also be applied to disc brake devices that generate friction force by pressing a friction member against a disc that rotates integrally with the axle, and track brake devices that generate friction force by pressing a friction member directly against the top surface of the track. Moreover, in the above embodiment, the case where the data acquisition device 4 is installed on a brake performance testing machine was described as an example, but the present invention can also be applied to bogies of railway vehicles running on the track.

[0090] (2) In the above embodiment, the example described is the use of particle measuring device 11 to measure suspended particulate matter such as PM10, PM2.5, or ultrafine particles with a particle size of 10 μm or less. However, the present invention can also be applied to the use of particle measuring device 11 to measure dust, abrasive powder, or abrasive pads. In addition, in the above embodiment, the example described is the measurement of particulate matter M generated when the wheel 1 and brake block 3 are in frictional contact. However, the components in frictional contact are not limited to the wheel 1 and brake block 3. For example, the present invention can also be applied to the measurement of particulate matter generated by frictional contact between the friction member on the driving side and the friction member on the driven side of a clutch device that transmits power from the driving side to the driven side, frictional contact between the grounding brush that releases electricity from the rotating body and the rotating body, frictional contact between the workpiece and the tool, frictional contact between the sliding contact line and the sliding plate, frictional contact between the wheel and the track, etc. Moreover, in the above embodiment, the example described is the case where one of the multiple components in frictional contact rotates while the other component stops. However, the present invention can also be applied to the case where two components in frictional contact rotate.

[0091] (3) In the above embodiment, the case of mutual frictional contact was described as one component rotating while the other component is stationary. However, the present invention can also be applied to the case where two components are in frictional contact while moving in a straight line, or where one component is rotating while the other component is moving in a straight line. In addition, in the above embodiment, the case where the cross-sectional shape of the rectifier grille 7a is circular, quadrilateral, or hexagonal was described as an example. However, the present invention can also be applied to the case where the cross-sectional shape is elliptical, triangular, or polygonal.

[0092] (4) In the above embodiment, the case of air being drawn in the vertical direction (longitudinal direction) using the suction pipe section 6 was described as an example, but the present invention can also be applied to the case of air being drawn in the horizontal direction (lateral direction) using the suction pipe section 6. For example, it can also be configured as follows: Figure 10 The acquisition device 4X shown is as follows: Figure 11 The acquisition device 4Y shown is used. Although in Figure 10 , Figure 11 The illustration is omitted, but similar to the embodiment described above, a particle measuring device 11 is connected to the rear end of the collecting unit 8. This constitutes a measuring system equipped with either the collecting device 4X or the collecting device 4Y. Furthermore, in Figure 10 The bending direction of the bend in section 6B is shown from the top. Figure 11 The bending direction of the bend in section 6B is shown as below, but it can also be set to a horizontal direction (towards...). Figure 10 (In the direction towards the front or the inside). In addition, in the above embodiment, the case where the exhaust unit 9 uses a centrifugal fan such as a multi-bladed fan was described as an example, but the present invention can also be applied to the case where the exhaust unit 9 uses a turbine fan that is the same centrifugal fan as a multi-bladed fan.

[0093] [Summary]

[0094] The contents disclosed in this specification can be summarized as follows.

[0095] (Technical Solution 1)

[0096] A device for collecting particulate matter, wherein,

[0097] The device for collecting particulate matter has the following features:

[0098] The suction pipe section draws in air containing the particulate matter;

[0099] The rectifier section rectifies the airflow within the suction pipe section into a laminar flow state.

[0100] The exhaust section discharges the air drawn into the suction pipe section to the outside of the suction pipe section; and

[0101] The collection unit collects air flowing within the suction pipe section.

[0102] (Second technical solution)

[0103] According to the data acquisition device of the first technical solution, wherein,

[0104] The collection device also includes a dust collection section, which allows the heavier particles in the particulate matter to fall off for dust collection.

[0105] The dust collection section discharges air containing the lighter particulate matter into the suction pipe section.

[0106] (Technical Solution 3)

[0107] According to the acquisition device of the first or second technical solution, wherein,

[0108] The suction pipe section draws air containing the particulate matter in the direction of the wind generated by the movement of the friction contact component.

[0109] (Technical Solution 4)

[0110] According to the data acquisition device of any one of the technical solutions 1 to 3, wherein,

[0111] The suction pipe section draws air containing the particulate matter from below upwards.

[0112] (Technical Solution No. 5)

[0113] According to the data acquisition device of any one of the technical solutions 1 to 3, wherein,

[0114] The suction pipe section draws air containing the particulate matter in a horizontal direction.

[0115] (Sixth technical solution)

[0116] According to the data acquisition device of any one of the technical solutions 1 to 5, wherein,

[0117] Let L be the total length of the straight section of the suction pipe section, and D be the inner diameter of the suction pipe section.

[0118] The distance from the inlet of the suction pipe to the collection port of the collection section is 0.4L to 0.8L.

[0119] The inner diameter of the rectifier grille in the rectifier section is 0.02D to 0.10D.

[0120] The length of the rectifier grille is 0.5D to 1.0D.

[0121] (Seventh technical solution)

[0122] A measurement system comprising a collection device according to any one of the first to sixth technical solutions, for measuring the particulate matter collected by the collection device.

[0123] (Technical Solution No. 8)

[0124] A collection method for collecting particulate matter generated due to frictional contact, wherein...

[0125] The data acquisition method includes the following steps:

[0126] The airflow within the suction pipe section is rectified in such a way that the airflow within the suction pipe section containing the particulate matter is in a laminar flow state.

[0127] The air drawn into the suction pipe is discharged out of the suction pipe; and

[0128] The airflow flowing within the suction pipe section is collected.

[0129] (Technical Solution No. 9)

[0130] A determination method, comprising a collection method of the eighth technical solution, for determining the particulate matter collected using the collection method.

[0131] Explanation of reference numerals in the attached figures

[0132] 1. Wheel; 1a. Tread; 2. Braking device; 3. Brake block; 3a. Friction surface; 4. Collection device; 5. Dust collection section; 6. Suction pipe section; 6A. Straight pipe section; 6B. Bend pipe section; 7. Rectifying section; 7a. Rectifying grid; 8. Collection section; 8a. Collection port; 9. Exhaust section; 10. Support section; 11. Particle measuring device; 12. Flow velocity measuring device; M, Particulate matter; M1, Lighter particulate matter; M2, Heavier particulate matter; F, Fluid; △, Gap.

Claims

1. A device for collecting particulate matter, wherein, The device for collecting particulate matter has the following features: The suction pipe section draws in air containing the particulate matter; The rectifier section rectifies the airflow within the suction pipe section into a laminar flow state. The exhaust section discharges the air drawn into the suction pipe section to the outside of the suction pipe section; and The collection unit collects air flowing within the suction pipe section.

2. The data acquisition device according to claim 1, wherein, The collection device also includes a dust collection section, which allows the heavier particles in the particulate matter to fall off for dust collection. The dust collection section discharges air containing the lighter particulate matter into the suction pipe section.

3. The data acquisition device according to claim 1 or 2, wherein, The suction pipe section draws air containing the particulate matter in the direction of the wind generated by the movement of the friction contact component.

4. The data acquisition device according to any one of claims 1 to 3, wherein, The suction pipe section draws air containing the particulate matter from below upwards.

5. The data acquisition device according to any one of claims 1 to 3, wherein, The suction pipe section draws air containing the particulate matter in a horizontal direction.

6. The data acquisition device according to any one of claims 1 to 5, wherein, Let L be the total length of the straight section of the suction pipe section, and D be the inner diameter of the suction pipe section. The distance from the inlet of the suction pipe to the collection port of the collection section is 0.4L to 0.8L. The inner diameter of the rectifier grille in the rectifier section is 0.02D to 0.10D. The length of the rectifier grille is 0.5D to 1.0D.

7. A measuring system, wherein, The measuring system includes the collection device according to any one of claims 1 to 6, for measuring the particulate matter collected by the collection device.

8. A collection method for collecting particulate matter generated by frictional contact, wherein, The data acquisition method includes the following steps: The airflow within the suction pipe section is rectified in such a way that the airflow within the suction pipe section containing the particulate matter is in a laminar flow state. The air drawn into the suction pipe is discharged out of the suction pipe; and The airflow flowing within the suction pipe section is collected.

9. A determination method, wherein, The determination method includes the collection method described in claim 8, for determining the particulate matter collected using the collection method.

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