Have you ever watched professional painters and wondered why they are pushing the roller so slowly? Here's Why.
Most wall paints are formulated to reduce in viscosity when they are agitated by rolling or brushing so they will flow out smoothly. But go too fast and they will reduce so much that they splatter.
In engineering and physics circles, they are known as pseudoplastic Non-Newtonian fluids. Other Non-Newtonians can increase in viscosity with agitation.
A good example is quick sand, which is fine sand or silt which is saturated with water, perhaps from an underground spring. If you step into quick sand, DO NOT PANIC or the quick sand will become more viscous and it may be almost impossible to escape. Instead go slowly and keep the viscosity more water-like.
Other Non-Newtonians include ketchup, blood, printing inks, some lubricants and many industrial materials. Depending on the material, Non-Newtonians can either increase or decrease in viscosity with agitation.
Richway Airpinch brand pinch valves are ideal for controlling Non-Newtonian fluids because they cause little agitation which prevents changes in viscosity.
Posted by Rich Borglum
at
16:39