Dry Disperser RODOS

Particle sizing of fine dry powders with the renowned dry disperser RODOS with vibratory feeder VIBRI
inserted in the measuring zone of HELOS/BR

Technical specifications and dimensions.

The RODOS is an universal dry dispersing unit applicable for nearly all kinds of dry powders with particle sizes in the range from < 0.1µm to about 3500 µm. The patented combination of feeding and dispersing enables a smooth, complete, product adaptable dispersion, which is widely extended into the SUBMICRON range.

For the optimum adaptation to the particle size the RODOS dispersing line is available with inner diameters of

4 mm	recommended for 0.1 µm < x_max < 1000 µm,
6 mm	recommended for 1 µm < x_max < 2000 µm) and
10 mm	recommended for 10 µm < x_max < 3500 µm.

RODOS can be used with all members of the HELOS family.

Dosing Options

Prerequisite of a good dispersion is a smooth and homogeneous dosing. Three different dosing methods are available (for micro-dosing please refer to the ASPIROS).

For most types of sample material the combination of vibratory feeder VIBRI and the inlet funnel connected to the dispersing line is sufficient to produce an excellent dispersed aerosol beam.

For extremely fine or adhesive, sticky products the rotating table with stripper and compacting roller may be the optimum solution. Here the dosing is performed in three steps:

1.	Filling of the groove of the table rotating at constant velocity with the vibratory feeder VIBRI.
2.	Compacting the sample with a roller.
3.	Removing the excess material.

The sample is taken out of the groove with a rotating brush or a protruding aspiration tube.

For operation of RODOS an extraction unit is provided for sample collections and the generation of a laminar air flow in the measuring zone of the HELOS.

Dry disperser RODOS with dosing unit VIBRI and funnel

RODOS with VIBRI and inlet funnel.

Top view of dry disperser RODOS with rotating table

Top view of RODOS.

Dry disperser RODOS with dosing unit VIBRI and funnel

RODOS with VIBRI feeding adhesive powders into the groove of the rotating table. The brush pre-disperser connected to the dispersing line takes a constant flow of sample material out of the groove of the rotating table, feeding it into the dispersing line.

Dry disperser RODOS with rotating table and protruding aspiration tube

RODOS with the protruding aspiration tube connected to the dispersing line taking a constant flow of sample material out of the groove of the rotating table and feeding it into the dispersing line.

Aerosol Jet

RODOS aerosol jet

RODOS aerosol jet in the open measuring zone with particles "glowing" in the laser beam

Dispersing principle

Following the vacuum generated through expansion of compressed gas applied to the injector, the agglomerates of fine dry particles arrive at low speed in the dispersing line and are subject to immediate acceleration. Three effects are available for the dispersion:

1. particle-to-particle collisions,

Dry dispersion: particle-to-particle collisions

2. particle-to-wall collisions and

Dry dispersion: particle-to-wall collisions

3. centrifugal forces due to strong velocity gradients.

Dry dispersion: centrifugal forces

Control Panel

The standard mode operation of RODOS is via control of the WINDOX software. The RODOS can also be operated manually via the operational panel.

RODOS operating panel

The panel allows for the control of Start/Stop of the different dosing units, the extraction unit, the setting of the rotational speed of the rotating table. The primary pressure and the vacuum generated by the dispersing line are displayed.

Dosing Options

RODOS Dry dispersion for laser diffraction < 0.1 µm - 3500 µm

Aerosol Jet

Dispersing principle

Control Panel

RODOS
Dry dispersion for laser diffraction
< 0.1 µm - 3500 µm