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P a r r I n s t r u m e n t C o m p a n y
Stirrer Options
Turbine Type Impellers
P
arr reactors are usually equipped with turbine
type impellers which produce an excellent
mixing action over the range of stirring speeds
at which these reactors typically operate. These
impellers are made in four-blade and six-blade
styles, with the smaller four-blade impellers
used only on Micro and Mini Reactors. These
impellers, for reactors with 300 mL volume or
greater, may be positioned anywhere on the
stirring shaft, with one impeller usually located
near the bottom of the vessel to keep solids up
in suspension and a second impeller positioned
near the base of the vortex to pull reactant gases
down into the liquid phase. These impellers gen-
erally provide excellent mixing for systems with
effective viscosities up to approximately 25,000
centipoise (cP) with a 16 in-lb magnetic drive or
up to 50,000 cP with 60 in-lb magnetic drive.
Anchor Stirrers
Anchor stirrers are available in several config-
urations for use with moderate to high viscosity
materials. This type of stirrer usually works best
in vessels with an inside depth to diameter ratio
of 1.5 to 1 or less. They are intended to operate
at relatively slow speeds and generally require a
heavy duty drive system capable of generating
and delivering sufficient torque to the agitator.
Footless magnetic drives work well with anchor
or spiral stirrers.
Three basic types are offered:
1. A U-shaped, flat bar anchor.
2. A flat blade, paddle type anchor.
3. A two-arm or three-arm, self centering
anchor with PTFE wiper blades.
All of these designs may not be appropriate or
available for each reactor size. Please contact the
Parr Technical Service Department for assistance
in selecting an anchor stirrer suitable for the
intended operating volume and viscosities.
Spiral Stirrers
Spiral stirrers can be installed in any 1 liter,
2 liter or 1 gallon reactor to produce a positive
downward thrust or upward thrust action when
working with viscous polymers or other high
viscosity mixtures. They work best in floor
stand reactors with adjustable speed and heavy
duty drive systems. Either left-hand (downward
thrust) or right hand (upward thrust) spirals are
available. The downward thrust spiral is gener-
ally preferred for heavy suspensions.
Note:
Additional internal fittings may be required to
adapt some stirrer styles to existing reactors in
the field.
Turbine Type Impeller
Spiral Stirrer
Gas Entrainment Impeller
Anchor Stirrer
Paddle Type Anchor
Anchor Stirrer with Wiper Blades
