The Marsh Funnel Viscometer is a rugged, easy to
operate instrument that is used for making rapid,
on the spot measurements of drilling mud viscosity.
Marsh Funnel readings are only general measurements,
but the frequent reporting of the Marsh Funnel Viscosity
will alert the mud engineer to sudden changes in the
mud viscosity that could require corrective action.
The Marsh Funnel Viscosity is the ratio of the speed of
the mud as it passes through the outlet tube (the Shear
Rate) to the amount of force- the weight of the mud itself,
which is causing the mud to flow (the Shear Stress).
Marsh Funnel Viscosity is reported as the number of
seconds required for one quart of mud to flow out of a
full Marsh Funnel.