THE BUSINESS OF VISCOSITY BLOG



    Why Can’t I Get a Reliable Viscosity Measurement on My Thixotropic Fluid with a Zahn Cup? – Part III

    Posted by Mike Bonner

    Aug 13, 2019 4:14:00 PM

    In Part II of this series, we continued our discussion on viscosity by tackling the topic of thixotropy.  With this defined, we can now circle back to bring it all together and show how different measurement methods produce different results and how our measurement choices can actually work against us.

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    Topics: Zahn cups, Efflux Cups, fluid process control, viscometers, viscometry, non-newtonian fluids

    Why Can’t I Get a Reliable Viscosity Measurement on My Thixotropic Fluid with a Zahn Cup? – Part II

    Posted by Mike Bonner

    Aug 6, 2019 3:38:00 PM

    In Part I of this series, we examined some of the issues with the viscosity cup measurement process and started to look at the fundamentals of fluid viscosity as a means of explaining the source of those problems.  In this installment, we pick up the discussion with a somewhat difficult topic:  thixotropy.

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    Topics: Zahn cups, Efflux Cups, fluid process control, viscometers, viscometry, non-newtonian fluids

    Why Can’t I Get a Reliable Viscosity Measurement on My Thixotropic Fluid with a Zahn Cup? – Part I

    Posted by Mike Bonner

    Jul 30, 2019 10:28:00 AM

    Manufacturers who dispense fluids in their process (i.e. – paints and coatings, sealers and adhesives, potting compounds and encapsulants, etc.) all understand that the viscosity of that fluid is fundamental to the process out

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    Topics: Zahn cups, Efflux Cups, fluid process control, viscometers, viscometry, non-newtonian fluids

    5 Common Misconceptions About Zahn Cups

    Posted by Saint Clair Systems

    Feb 4, 2018 1:00:00 PM


    To determine the viscosity of a liquid, a Zahn cup is dipped and completely filled with the liquid to be measured. After lifting the cup out of the liquid, the user measures the time it takes for the liquid streaming from the opening in the bottom of the cup to begin “breaking up.” This is the corresponding "efflux time." 

    (Quick note:  Efflux is defined as “the flowing out of a particular substance or particle.” Cups of this nature may be more recognizable by names like Zahn Cup, Shell Cup, or Ford Cup. For purposes of this blog, I am using the Zahn cup to refer to all efflux cups). As I am fond of saying, it's not rocket science it's fluid science, (which requires a degree of education).

    Sounds simple right?

    It is!

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    Topics: Viscosity, Zahn cups

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