Application and development of laser particle size analyzer
by:GESTER Instruments
2021-04-29
1. Introduction to the laser particle size analyzer The laser particle size analyzer analyzes the particle distribution by measuring the diffraction spectrum of a particle group and processing it by a computer. It can be used to measure the particle size distribution of various solid particles, droplets, bubbles and any two-phase suspended particulate matter, and to measure the particle size distribution of moving particle groups. It is not limited by the physical and chemical properties of the particles. This type of instrument has a wide measurement range (measurement range can reach 0.02~2000 microns, and some even wider) because of its ultrasonic, stirring, and circulating sample dispersion system; it has a high degree of automation; it is easy to operate; it is fast in testing; measurement results Accurate, reliable and repeatable. It can be widely used in the determination of particle size of petrochemical industry, ceramics, dyes, cement, coal powder, abrasive materials, metal powder, silt, ore, fog drop, emulsion, etc. Such as domestic JL and WJL series laser particle size analyzers, British Mastersizer series laser particle size analyzers, and PCS nano particle size analyzers that can be used to measure nanometers. 2. The basic principle of measurement The laser particle size analyzer measures the particle size distribution based on the physical phenomenon that particles can cause the laser to scatter. Because the laser has good monochromaticity and strong directivity, a parallel laser beam will illuminate infinitely far away in an infinite space without obstruction, and there is little divergence in the propagation process. When the beam is blocked by particles, a part of the light will scatter. The propagation direction of the scattered light will form an angle θ with the propagation direction of the main glory. Scattering theory and results prove that the size of the scattering angle θ is related to the size of the particle. The larger the particle, the smaller the θ angle of the scattered light; the smaller the particle, the larger the θ angle of the scattered light. The classic optical route of the laser particle size analyzer is composed of three parts: emission, reception and measurement windows. The emission part is composed of a light source and a beam processing device, mainly to provide a monochromatic parallel light as an illuminating light for the instrument. The receiver is the key to the optical structure of the instrument. The measurement window is mainly to allow the tested sample to pass through the measurement area in a completely dispersed suspension state, so that the instrument can obtain the particle size information of the sample. The receiver consists of a Fourier selector and a photodetector array. The so-called Fourier selection is to eliminate aberrations when the object side is at infinity and the image side is at the back focal plane. The optical structure of the laser particle size analyzer is an optical Fourier transform system, that is, the observation surface of the system is the back focal surface of the system. Since the light intensity distribution on the focal plane is equal to the square of the mathematical Fourier transform modulus of the light amplitude distribution function of the object (no matter where it is placed in front of the lens), that is, the spectrum of the light amplitude distribution of the object. The laser particle analyzer puts the detector on the back focal plane of the lens, so the parallel light of the same propagation direction will be focused on the same point of the detector. The data detector is composed of multiple concentric rings centered on the optical axis, and each ring is an independent detection unit. Such detectors are also called circular photodetector arrays, or photodetector arrays for short. After focusing, low-pass filtering and collimation, the laser beam emitted by the laser becomes parallel light with a diameter of 8-25 mm. After the parallel beam hits the particles in the measurement window, it scatters. After the scattered light passes through the Fourier lens, the light with the same scattering angle is focused on the same radius of the detector. The photoelectric signal output by a detection unit represents the scattered light energy in an angular range (the size is determined by the difference between the inner and outer radii of the detector and the focal length of the lens), and the signals output by each unit constitute the distribution of scattered light energy. Although the intensity distribution of scattered light is always large at the center and small at the edge, the area of u200bu200bthe detection unit is always small inside and large outside, so the peak of the measured light energy distribution is generally on a certain unit between the center and the edge. When the particle diameter becomes smaller, the distribution range of the scattered light becomes larger, and the peak value of the light energy distribution also shifts outward. Therefore, particles of different sizes correspond to different light energy distributions. On the contrary, the particle size distribution of the sample can be calculated from the measured light energy distribution. The lower limit of measurement is an important technical indicator of the laser particle size analyzer. The improvement of the optical structure of the laser particle sizer is basically to extend the lower limit of measurement or the resolution of the small particle segment. The basic idea is to increase the measurement range of scattered light, the measurement accuracy or reduce the wavelength of the illuminating light. 3. The structure of the laser particle size analyzer. The instrument system mainly includes three parts: 1) the host (optical element), marked as MasterSizer 2000; the host is used to collect the raw data of the particle size in the sample. 2) Attachment (sample injector), identified as Hydro 2000G (ordinary wet method); the sole purpose of the attachment is to disperse and mix the sample sufficiently and send it to the host for measurement. 3) Computer and Malvern measurement software; Malvern software can define and control the entire measurement process, and process the measured particle size distribution data, display the results and print reports at the same time.
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GESTER International Co.,Limited has a number of producing line for producing textile testing equipment.
Our commitment to equal employment and diversity is a global one as we serve customers and employ people around the world. GESTER International Co.,Limited finds it as a business imperative that is essential to thriving in a competitive global marketplace.
tensile tester manufacturers problems are nothing new, almost every one of us have to go through them at some point of our lives and some of us never get rid of them. with the development of tensile tester manufacturers technology, now provides a perfect cure for that.
come in many forms, like tensile tester manufacturers and tensile tester manufacturers, and they all provide efficient solution for our tensile tester manufacturers needs.
And finally, if you want to find additional resources for textile testing equipment, simply go to GESTER Instruments for more.
GESTER International Co.,Limited has a number of producing line for producing textile testing equipment.
Our commitment to equal employment and diversity is a global one as we serve customers and employ people around the world. GESTER International Co.,Limited finds it as a business imperative that is essential to thriving in a competitive global marketplace.
tensile tester manufacturers problems are nothing new, almost every one of us have to go through them at some point of our lives and some of us never get rid of them. with the development of tensile tester manufacturers technology, now provides a perfect cure for that.
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