Preparations
Before the measurements can be started the thermostatic bath should be brought to the correct temperature. Temperature stability is of extreme importance in order to obtain valid and repeatable results. For low temperatures, e.g. 40°C, the warm-up time will be less than 10 minutes and the bath will be sufficiently stable within 45 minutes.

For measurements below room temperature an additional cooling spiral has been integrated in the system to which an external water cooler can be attached.

Measuring and cleaning
Because of the small sample size, sample warm-up requires very little time. After warming up, the samples flows down the capillary and passes the first optical sensor, which triggers the time measurement. When the sample has passed the second sensor, the time measurement is stopped and the result displayed or printed out to the optional printer. The system presents both single measurement results, as well as average results, based on a user-defined number of measurements.

Immediately after the measurement, the system starts to clean the viscometer by running a preset user-defined cleaning cycle. The user can set all parameters for cleaning, such as :

• sample evacuation time
• nr. of injections
• quantity per injection
• interval between injections
• drying time

The S-flow 1200 can optionally provide dual solvent injections. This may be required if measurements are performed at relatively low temperatures (25-40ºC) at which the solvent that is used for cleaning does not evaporate quickly enough. In these cases, rinsing with a second solvent with a lower boiling point facilitates easy drying.