Helipath Viscometer Stand
Successful Viscosity/Consistency Measurments of Gels, Pastes and other Non-Flowing Substances
The Brookfield Helipath Stand, when used with a suitable Brookfield Viscometer fitted with a special T-bar type spindle, will permit viscosity/consistency measurements in relative centipoise values of materials having characteristics similar to paste, putty, cream, gelatin, or wax.
Many substances, because of the nature of their yield values, have previously been considered unsuited for viscosity or consistency measurements with rotational Viscometers. Any rotating member, be it cylinder, disc, or paddle, will create a “channel” in such substances and after a very short time exert a negligible and meaningless torque on any sensing device. This effect also occurs with materials that have a gel structure.
Paint dyes, lithographic inks, and many other substances are thixotropic in that their structure is broken down and their viscosity is decreased when subjected to internal shearing. While no rotating member will ever spin freely in such materials, the torque required to produce this motion will become less as the period of internal shearing lengthens. The study of such data will lead to difficulties and necessarily rigid testing procedures in product control work.
Other materials, notably pastes and creams, show a combination of the two effects listed above. They will show a yield value as well as a change in relative viscosity/consistency with time.