Dry powders should be analysed dry
Compared to wet analysis where products are suspended in liquid first, the amount of sample analysed is significantly higher giving the user a more reliable result. No solvent is required and hence the sample is not affected by any solvent at all. Moreover the analysis time decreases into the second to millisecond range.
For product specific dry dispersion different dispersing modules are available.
The GRADIS family of Gravity Dispersers for coarse particles up to 8750 µm
GRADIS & VIBRI |
These units is ideal for products that do not need a high dispersing energy, like crystals, sand, granules etc. The fall shaft provides smooth dispersion and controls and equals the speed of the particles presented to the laser beam. If required, the sample can be collected and re-used after the analysis. GRADIS (GRADIS/L) is fed by VIBRI (VIBRI/L), the software controlled feeding device suitable for all dry dispersing units. |
The RODOS family for particles from 0.1 to 3500 µm
HELOS & RODOS shown with vibratory feeder VIBRI |
Using compressed air to disperse even the finest powder this module generates a dry aerosol which is blown through the laser beam and collected in a suction after the analysis. Particle-particle-collisions, particle-wall-collision and velocity gradients are applied within the RODOS injector for complete dispersing of the sample. The dispersion energy can be adapted to the demands of the product. RODOS/M (RODOS/L) as the fully automated version of RODOS is completely controlled by software. The correct product dependent dispersion force is automatically chosen by the software's database. This makes RODOS/M (RODOS/L) ideal for validated applications e.g. in the pharmaceutical industry. The sample feeding for RODOS & RODOS/M (RODOS/L) can be done by VIBRI (VIBRI/L) or the micro-dosing device ASPIROS (ASPIROS/L). For special applications RODOS and the measuring zone can be enclosed. If not only dry powder analysis is your daily lab business but also suspensions and emulsions are analysed, RODOS/M (RODOS/L) can be extended by SUCELL/M (SUCELL/L) into the multifunctional dry and wet dispersion module OASIS or OASIS/L. |
VIBRI and ASPIROS dosing units
VIBRI/L
ASPIROS |
A constant sample mass-flow is of decisive importance for powerful dry dispersing. The controlled vibratory feeding unit VIBRI (VIBRI/L), equipped with a built in amplitude controller feeds the sample constantly and independent of the load in the VIBRI funnel of RODOS or GRADIS. The vibration power and the funnel height are controlled by software for product dependant and reproducible sample feeding. The funnel as well as the chute are available in different geometries and sizes, specially coated, conductive or non-conductive to satisfy the demands of the product. If only small quantities of valuable product or toxic material are to be analysed, the micro-dosing device ASPIROS (ASPIROS/L) can be applied. ASPIROS is mounted instead of the RODOS funnel. Its encapsulated sample chute is prepared and filled with a few micrograms in a glove box or a fume cabinet. The sealed sample tube is inserted into ASPIROS. The unit's bar code reader identifies the sample, automatically applies the correct dispersion settings and releases the sample into the RODOS injector for analysis. Having an encapsulated HELOS measuring zone, no product is exposed to the environment |
