Dosing unit


Actuator for metered dose aerosols, pump and propellant gas bottles for particle and droplet size characterization within generated spray cones

The SMACTOR with universal rack is a versatile adapter designed to measure particle and droplet size distributions using the HELOS/KR-Vario laser diffraction sensor of a wide range of bottle types. As the results are usually depending on a variety of parameters driving the spraying process, e.g. the force and the path-velocity behaviour, the spraying process has to be performed under controlled reproducible conditions.

The intelligent SMACTOR actuator supports both stroke-acceleration and force-controlled actuation and simulates manual release. With a variety of individually assignable parameters such as acceleration, maximum velocity, stroke length, maximum force and their rise time, the actuator enables user-defined and reproducible release profiles.

In combination with a universal rack SMACTOR is used in free experimental set-ups in the HELOS/KR-Vario. The universal rack with spring-loaded holding mechanism is flexibly adjusted to many different types of bottles, such as MDI, pump or propellant gas bottles and enables a variety of different spray applications.

The complete actuation process is controlled and monitored by the software for subsequent evaluation. The monitoring of the measurement can be performed by the application software in four different modes:

  • Integration of the diffraction intensities over the complete spray process
  • Separation of the result into three phases: formulation phase, stable phase, dissipative phase, as requested by e.g. the FDA
  • Time resolved measurements with definable resolution up to 2,000 particle size distributions per second
  • Time-segmented measurements with subsequent identification of the stable phase and summary of the corresponding segment for evaluation

For the operation an extraction unit is recommended for sample collection and the generation of a laminar air flow in the measuring zone of the HELOS. In combination with the SPRAYER adapter, SMACTOR is suitable for measuring the droplet size distribution of nasal and pharyngeal pump sprays.

Typical Configuration


Aerosols | Sprays
Size range: 0.25 µm - 1,750 µm
Method: Laser Diffraction

Suited for

Applied for control of