Humidified Tandem Differential Mobility Analyzer Model 3100


Experience the only fully-characterized, commercially available HTDMA backed by over two decades of aerosol water uptake measurement expertise.

Most particles in the atmosphere take up water when exposed to increasing relative humidity – this often explains the poor visibility during the early morning hours when the relative humidity is high and particles have swollen in size and more effectively scatter solar radiation. When we inhale particles they also grow into water droplets, how large they grow determines where they deposit in our respiratory systems. Brechtel developed the first commercial version of the Humidified Tandem Differential Mobility Analyzer (HTDMA) so researchers who wanted to explore the complexities of particle water uptake no longer had to build their own system, instead they could rely on our 20 plus years of experience with HTDMAs to invest in a solution that would let them focus on their science and not the tool. With the broadest selectable size range up to 2 microns and controllable humidity between 10 and 93%, the HTDMA uses an auto-scheduler software to continuously run the experiments you want completely unattended.

Learn About Product

All Features
  • Fully automated and field tested
  • Characterized in peer-reviewed literature
  • Easy-to-use experiment scheduler software
  • Large particle performance: select up to 2 microns
  • Rapid RH and particle size changes
  • Fast response barrier-free diffusion-based humidifier
  • Easily integrated with chemical composition devices
  • Integrated aerosol generation system (optional)
  • Integrated thermodenuder (optional)
  • Integrated pre-humidifier (optional)
  • Rack mount kit (optional)
  • Characterized in peer-reviewed literature
  • Easily integrated with chemical composition measurement devices
  • Years of continuous field deployment
  • Backed by over 20 years of HTDMA measurement experience
Technical Specs

Copyright ©2022 All specifications are subject to change without notice. BMI assumes no responsibility for inaccuracies in this document or for any obligation to update information in this document. BMI reserves the right to change, modify, transfer or otherwise revise this publication without prior notice.

*Some products may be shown with optional accessories, which are sold separately. Items shown may not be to scale.

Applications and Solutions
  • Aerosol climate impact studies
  • Measurement of hygroscopic growth of rapidly evolving aerosol size distributions
  • Cloud condensation nucleus studies
  • Visibility reduction studies
  • Aerosol health impacts
  • Long-term climate and air quality monitoring
  • Process monitoring
  • Tobacco smoke inhalation studies
The HTDMA software runs on a Windows PC integrated into the instrument and features a graphical user interface with point-and-click operation. A real-time display of particle water uptake is available through plots of measured number concentration versus growth factor and physical size. Data are displayed as raw counts, raw concentration and processed concentration. System overview and detailed operating parameter views make it easy to determine if the instrument is operating within specification. Data is inverted on-line using a simplified inversion process for quickly viewing and analyzing results. An easy-to-use data post processing software tool written in Igor™ applies the full HTDMA transfer function to invert raw measurement data accounting for the full instrument response function.

The built-in experiment scheduler in the software allows you to pre-define your sequence of runs by setting the selected dry size, exposure RH, scan range, and number of repeated scans. With the HTDMA Auto-atomizer option, the software can automatically valve in and operate an atomizer to generate known composition aerosol to test instrument performance. The software flexibility lets you complete all the runs you wish to perform and leave the HTDMA unattended while it does the work for you!

What's Included
• Scanning Electrical Mobility Sizer with dryer, 2um DMA and MCPC
• Humidified Scanning Electrical Mobility Sizer (HSEMS) with 2um DMA, Diffusion-based Humidifier and MCPC
• Software to control HTDMA operation
• Software to allow upstream SEMS to run in scanning mode during HTDMA operation
• Keyboard, monitor, and mouse for HSEMS computer
• Igor™ licenses for SEMS laptop and HSEMS computer
• Interconnect tubing and cables
• Operator’s manual
• Weatherproof shipping case for SEMS
• Rugged wooden shipping container for HSEMS
The following optional accessories are available:

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