Rheology Testing Equipment

Most of the data regarding Spraying Systems Co. products are provided for water, but most of the fluids our customers spray are not pure water. Water provides a useful baseline, but fluid properties such as viscosity, surface tension and density (specific gravity) can have a significant effect on the resulting spray plume characteristics generated by a nozzle. 

Rheology Assessment Overview
We utilize commercially available instruments to characterize fluid rheology properties. These instruments may be used alone or as part of a spray test by determining or setting the material properties prior to spray characterization. 

Rheology assessments are conducted with the following equipment:

  • Brookfield DV2TLV Viscometer (viscosity)

  • Kruss K20 Tensiometer (surface tension, density)

  • Pycnometer Bottle (specific gravity)

  • Refractometer (index of refraction)

Benefits of Rheology Testing

Understanding the fluid properties like viscosity, surface tension and density can be very helpful in selecting nozzles to properly distribute and atomize any material. Knowing these properties allows for engineers to more accurately select a nozzle for a given fluid and application. Furthermore, understanding detailed rheological trends, such as viscosity versus temperature or shear rate, can often explain the difference between spraying at different locations with different process controls.

Examples of Rheology Testing for Customers

We’ve performed countless rheology assessments for customers across many industries and applications.

  • Automotive Coating
    An automotive supplier contacted Spraying Systems Co. requesting proof of concept testing to spray-coat a substrate with a new formulation. Viscosity, surface tension and density were analyzed first, which helped focus in on the style of nozzle to attempt to spray this slurry. The analysis resulted in a quick determination of the appropriate nozzle, allowing additional time to test for the optimal nozzle operating conditions, height and spacing to evenly coat a wide-moving substrate with multiple overlapping nozzles.

  • Food Heating for Coating
    A food manufacturing company required a nozzle to spray coat a substrate. The material was heated and successfully sprayed in the Spraying Systems Co. lab. After returning to the production facility, the customer experienced issues recreating the spray solution. It was determined the spray material temperature was not carefully controlled at the production facility. A second round of testing was conducted, and the spray quality was examined while reducing the material temperature and examining the resulting material viscosity change. An acceptable range of temperature was determined, based on the viscosity trend, to allow for an acceptable spray. This new information allowed the production facility to be monitored and controlled with adequate precision, using the known temperature requirements.

Example Data

Viscosity vs. Temperature  
Viscosity vs. Shear Rate  

 

Want to learn more about the characteristics of your spray operations? Contact us