The Brookfield Helipath Stand
, when used with a suitable Brookfield Viscometer/Rheometer 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 a 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.
The Brookfield Helipath Stand is designed to slowly lower or raise a Brookfield Viscometer so that its rotating shearing element will describe a helical path through the test sample. By always cutting into fresh material the problem of “channeling” or separating is eliminated and meaningful viscosity/consistency measurements can be made. The reversing feature of the Helipath Stand allows measurements to be made over a variable period of time.
The Helipath Stand can be used with any Brookfield Viscometer and DV3T Rheometer and is supplied complete with a set of six T-Bar Spindles and a special coupling. Also available with EZ-lock option - call for pricing. Specification:
- Spindle: T-Type
- LV Viscosity Range: 156 - 3120 K
- RV Viscosity Range: 2 K - 20 M