The mixer
to best suit your needs will depend on
ten basic factors. One such factor is
the amount of "pumping capacity"
you will require. A simple way to understand
this is by "turnovers per minute"...the
tank capacity in one minute is "one
turn". Two turns per minute in a
500 gallon tank would be 1000 gallons
per minute in pumping capacity. One turn
per minute is considered "mild agitation"
which is used for liquid storage, pH adjustment,
etc. 1½ to 2 turns per minute is
considered "standard agitation",
for blending and general mixing. Three
or more turns could be used in solid suspension*
or fast mixing applications and is considered
"vigorous agitation."
Your
tank capacity ______________________
gallons
Your flow requirement ___________________
turns / minute
Interestingly
enough, you can achieve the same amount
of liquid flow when using a 11" impeller
at a speed of 1700 RPM (direct drive)
as you can by using a 36" impeller
turning at only 70 RPM. The difference
is that it takes a 20HP motor to turn
the smaller direct drive impeller while
it only takes a ¾HP motor to turn
the larger impeller. BIGGER AND SLOWER
IS BETTER. Not only do you save an enormous
amount of power but the slow speed also
improves wear and tear and cuts your maintenance
costs.
The characteristics
of the liquid(s) and materials you are
mixing will determine how strong the mixer
must be and what type of impeller you
will need.
Your
liquid's viscosity (thickness) __________
CPS (centipoises)
Your liquid's weight in lbs. or specific
gravity ________________
Solids (if any) see below* ______________________________
The dimensions
and configurations of your tank or vessel
will also dictate some of your agitation
requirements. A tall, thin tank may require
multiple impellers to get full top to
bottom mixing. For standard blending,
a ratio of 1 : 1 ½ tank diameter
to straight side is ideal. If baffles
are available, they should be about 1
/ 12 of the tank diameter in width. If
baffles are not available - as in most
plastic tanks, the mixer should be placed
off center about 20% of the tank diameter.
The shaft length will be determined by
the least amount of liquid you plan on
mixing in the tank, which is called the
"minimum bath level."
Your
minimum bath level - _______ gallons
or ______ % of the tank.
* For
solid suspension, a coned or dished bottom
should be used where possible. Obviously,
the weight, size and amount of solids,
and the degree of suspension that you
require will determine the power and pumping
capacity that are required.
Your
solids weight _____________ lbs. or
spec. gravity
Your solids particle size ________________
microns
Amount of solids by weight ___________
% (compared to liquid)
Amount of solids by weight ____ off-bottom
only ___ (check one only)
The chemical
make-up of the solutions being mixed will
determine what the wetted surfaces should
be. Check with Corrosion Resistant Technologies
800-245-3769.
Your
chemical(s) and, or solvents being blended:
____________
__________________________________________________
TOLL
FREE 1-800-245-3769
