Monodisperse Droplet Generator

MSP Corporation Announces a New Breakthrough in Monodisperse Droplet Generation

1530 MONODISPERSE DROPLET GENERATOR CALIBRATION SYSTEM

(PRWeb Press Release) Shoreview, Minnesota April 18, 2017

Summary: MSP's newly developed Model 1530 Monodisperse Droplet Generator (MDG) produces uniform monodisperse droplets as small as 15 microns in diameter. The 1530's small high precision droplets are very useful for evaluating the performance of laboratory laser phase Doppler systems.

Quote:The MDG produces small droplets without the clogging problems that a VOAG device typically has with very small orifices.

The Vibrating Orifice Aerosol Generator (VOAG) was developed in the 1970s and has been a key device for generating monodisperse droplets of known diameters for research applications such as for calibrating droplet measuring instruments, for studying droplet processes and for generating monodisperse solid particles by drying monodisperse droplets.

The VOAG requires forcing liquid out of an orifice about half the diameter of the desired droplets. Liquid jet emerging from the orifice is broken down uniformly using narrow-bandwidth ultrasonic excitations, so a single drop is formed during each cycle of ultrasonic perturbation. Diameters of the droplets thus produced are determined with a high accuracy as they carry the liquid volume forced out of the orifice in a single cycle of ultrasonic perturbation.

However, this excellent process of generating monodisperse droplets of known diameters becomes unreliable and difficult to implement with decreasing orifice diameters, as small orifices are prone to clogging and wear out under liquid pressure, thus making it difficult to generate small droplets. Over years, there has been a growing need for sub-50-micron droplets that cannot be easily produced using the VOAG device. MSP has recently solved this problem by using the ‘flow-focusing’ technique in combination with ultrasonic liquid jet breakup (patent pending). The newly developed Model 1530 Monodisperse Droplet Generator (MDG) uses a robust nozzle with a 100-micron diameter opening that is neither prone to wear nor clogging under normal operating conditions. The liquid jet issuing from the nozzle is attenuated to the desired diameter using flow-focusing air, which flows concentric to the liquid jet and accelerates it, thus reducing the jet diameter. The amount of energy in the flow-focusing air, controlled by its initial pressure, determines the final jet diameter, which can be as small as 10 microns.

The Model 1530 MDG has been extensively tested with ultrapure water and organic solvents (e.g. methanol and ethyl alcohol) and shown to generate a wide-range of droplet diameters from nearly 15 microns up to 100 microns. Unlike the VOAG, the MDG does not require hardware reconfiguration to cover this wide droplet size range. Tables and graphs are provided to choose operating conditions for generating the desired droplet diameters.

Using a touchscreen menu and a flow metering valve, Model 1530 provides convenient and user-friendly means to set three key parameters: liquid flow rate, ultrasonic frequency and flow-focusing air pressure. Proper choice of these parameters ensures stable output of monodisperse droplets of the desired size with a geometric standard deviation of 1.01-1.03. The droplet generating head is connected to the main body of the instrument via flexible tubing and an electrical signal cable, so it can be positioned with an arbitrary orientation at the desired location in an experimental setup, such as a setup involving characterization of sprays using the phase Doppler technique.

MSP is a privately-held division of TSI Inc. For over 30 years MSP has created micro- and nano-particle instrument and equipment technologies for scientific research and industrial applications. MSP is known world-wide for particle technology expertise in helping researchers and manufacturers solve tough problems with creative equipment designs. Contact MSP at sales(at)mspcorp(dot)com to discuss micro- and nano-particle application or research needs.

Contact: Francisco J. Romay, Product Manager, Aerosol Instruments

Original press release can be found at http://www.prweb.com/releases/2017/03/prweb14170934.htm

Cascade Impactor Technology Leaps Forward with MSP’s latest real-time QCM-MOUDI™ Impactor

Real-Time QCM-MOUDI™ Impactor

MSP’s real-time QCM-MOUDI™ Impactor is a leap forward in cascade impactor technology for size-fractionation and mass measurement of aerosols. The new QCM-MOUDI™ has a 25-nanogram mass resolution which is accomplished through humidity control and advanced electronics, while keeping samples available for post-collection analysis.

Researchers can now accelerate their aerosol studies by measuring aerosol mass in real-time with the breakthrough equipment technology contained in the QCM-MOUDI™ Impactor device from MSP.

Cascade Impactor History background

Cascade impactors have been used for collecting and size-fractionating aerosols for over a century. Significant advances were made in this technology in the late 1970s and early 1980s by MSP founders at the University of Minnesota. In particular, collection of nanometer particles (<100 nm) was enabled, and a uniform deposit feature was introduced (see Kuhlmey et al. 1981 and Marple et al. 1981). These advancements led to the Micro-Orifice Uniform Deposit Impactors (MOUDI™) introduced as commercial products by MSP Corporation. These precision cascade impactors are designed for sampling and collecting size-fractionated particle samples for gravimetric and/or chemical analyses. Several models of the MOUDI™ product line cover flow rates as high as 30 L/min and the lowest cut-sizes as small as 10 nm. The MOUDI differs from other conventional cascade impactors in the use of a large number of micro-orifice nozzles to reduce jet velocity and pressure drop, minimize particle bounce and re-entrainment, and enhance collection efficiency. As many as 6,000 nozzles with diameters as small as 50 μm are used. Some models also have the uniform-deposit feature achieved by rotating the impaction plate relative to the nozzles so that the particle deposits under the nozzles can be spread out uniformly over the entire impaction area.

MSP research yields the real-time QCM-MOUDI™

This new capability enables researchers to actively monitor aerosol mass measurements, while simultaneously collecting size-fractionated samples for post-collection analysis.

A Quartz Crystal Microbalance (QCM) is a sub-millimeter thick wafer cut out of a single crystal of quartz. Metallic films deposited on both sides of the wafer serve as electrodes that are used to probe the natural frequency of vibration of the QCM. QCMs can be mounted to the impaction surfaces of cascade impactors. The aerosol mass depositing on them results in a drop in the frequency proportional to the deposited mass. QCM surfaces can be cleaned after a measurement session and reused.

Early attempts to utilize QCMs for real-time aerosol mass measurement were hampered by technological problems including the failure of the aerosol to remain attached to the QCM as it vibrated at MHz frequencies. After meticulous investigation of the earlier anomalies in QCM response, MSP has developed a proprietary technology to reliably measure size-fractionated aerosol masses up to 100 micrograms. In particular, humidity conditioning of the sampled aerosol ensures reliable coupling of aerosols to QCMs (patent pending).

For over 30 years MSP has created micro- and nano-particle instrument and equipment technologies for scientific research and industrial applications. MSP is known world-wide for particle technology expertise in helping researchers and manufacturers solve tough problems with creative equipment designs. Contact MSP at sales(at)mspcorp(dot)com to discuss micro- and nano-particle application or research needs.

For the original version on PRWeb visit: http://www.prweb.com/releases/real-time-moudi-impactor/cascade-impactor/prweb13702090.htm