SLG 270 - Monodisperse Aerosol Generator

Condensation Aerosol Generator SLG 270 produce monodisperse aerosols with definined properties in a wide range of particle size and number concentration as well. The aerosol generation principle is based on the controlled heterogeneous condensation acc. to Sinclair-LaMer mentioned in the directive VDI 3491 part 4.

Depending on the choice of the particle material either droplet or solid state aerosols can be generated.
The patented innovative concept in combination with state of the art control instruments and regulators guarantees quick and reproducible adjustment of both particle size and concentration.Both parameters of the outlet aerosol can be continuously monitored by means of the Process Aerosol Monitor PAM 510.

Advantages

• Generation of monodisperse aerosols with reproducible adjustable particle size in a wide range
• Particles are round and uncharged (electrically neutral)
• Constant high number concentration, also in long-running operation
• Very rapid and reproducible adjustment of desired particle size (0.1…12 µm)
• Spherical and virtually electrically neutral particles

Applications

• Calibration of particle measuring instruments
• Aerosol research
• Filter testing
• Determination of separation efficiencies
• Inhalation and toxicology studies

Accessories

• Test Aerosol Liquid DEHS (80 ml, 0.5 l , 1 l or 20 l)
• Further aerosol substances e.g. DOP or Emery 3004 on request
• Drying agent Sorbsil (Slilica Gel)
• PAM 510: Process Aerosol Monitor for checking concentration and mean particle size

Principle

The HEPA-filter ensures cleanness of the carrier gas (nitrogen). In the atomizer a NaCl-solution is sprayed. Downstream the atomizer a diffusion dryer removes the water from the droplets to produce small crystals. The salt crystals concentration for the heterogeneous condensation is about 10⁶ … 10⁷ per cm³.
By means of the screen-bypass downstream to the diffusion dryer the nuclei concentration can be adjusted.

The size of the aerosol particles to be produced is mainly determined by the quantity of available vapour per nucleus. The vapour concentration can be adjusted by two parameters:

• Saturation of the nuclei aerosol at definite temperature
• Dilution of the saturated nuclei aerosol with not saturated nuclei aerosol by means of a saturator bypass

The saturation of the nuclei aerosol takes place in the saturator. The aerosol bubbles through the aerosol material which is held at constant temperature. Depending on the temperature and the material specific vapour pressure a definite saturation concentration of vapour is achieved in the bubbles. The bypass permits the more rapid adjustment of particle size by dilution, rather than by saturator heating or cooling. In the condensation chimney the superheated vapour-nuclei mixture is cooled down causing the vapour to condense onto the nuclei. For particularly high demands on the monodispersity only the core flow in the condensation chimney is exhausted.

The SLG 270 is also equipped with a screen unit for the defined salt core reduction (screen), which allows the generation of larger particles (Patent 43 12 983)

Specifications

• Adjustable Particle size range (aerodynamic diameter)    
  • DEHS    0.1 …  8 µm
  • Carnauba wax (solid)    0,1 …  5 µm
  • Stearic acid    0,1 … 12 µm
• Geometric standard deviation: <1.15
• Number concentration: 106 particles/cm³
• Total flow rate: 200 … 250 l/h
• Saturator temperature: up to 400 °C
• Reheater temperature: up to 400 °C
• Power supply *: 220 VAC / 50 Hz
• Carrier gas: 250 l/h / 8 bar
• Dimensions in mm: 550  x 300  x 250
• Weight: 16 kg