What
information is required to specify a Keller Pump/Skimmer?
There are four pieces of information required
to specify a Keller Unit:
 1)
The number of machines to be serviced
2)
The size of the sumps––Over or under about 100 gallons
is really
the key point.
3)
The materials being cut
4)
The coolant being used
With answers to these four questions, you can specify the right
Keller unit from the information on the product web pages, or
call a Keller representative at 800-352-8422 for a recommendation
on your specific requirements, based on our experience with
thousands of units in service.For most standard applications,
probably more than 90% of applications, you can focus on these
units:
TKO-6,
TKO-10, TKO-14 – General purpose units for single sumps
Model
#315 – Portable unit for 10+ sumps, about 100 gallon
sumps or smaller
Model
#457 – Portable unit for large sumps, and/or when a
heavy concentation of  solids
or oil is expected.
Click for complete information and prices on Keller Pump/Skimmer
Units:
Pump/Skimmers
for Single Sumps
Portable
Pump/Skimmers
What is the
comparison between dedicated units and portable units?
If you wish to service more than four machine sumps, the cost
per sump
is typically lower for a portable unit. For example, if you
purchase a
portable unit for $3000 and service 10 machines, the cost per
machine
is $300, compared to $795 for the least expensive dedicated
unit. The
downside to a portable unit is that it is less convenient than
having
one unit for each machine. Moving a portable unit to a new sump
requires only a few minutes, but the labor must be available
to do it.
The advantage of a dedicated system is that you are certain
the coolant in the machine is clean at all times. The coolant
is being cleaned continuously, and no one is required to move
the separator. A high percentage of shops with more than 10
sumps do employ dedicated units, even though the initial cost
is higher than for a portable unit. Running with clean coolant
at all times for a one-time cost of only about $800 per sump
can make your several hundred thousand dollar machine tool operate
more efficiently.
Either a portable or dedicated unit will quickly pay for itself
by multiplying coolant life, thus saving coolant purchase and
disposal costs, and greatly reducing machine downtime and labor
for coolant changes. In addition, a 10% increase in tool life,
typical with continuously cleaned coolant, will alone quickly
justify the cost of the Keller coolant cleaner. In fact, we
calculate that the cost of a Keller Pump/Skimmer will be paid
off in 4 months or less!
Click
here for calculation of payout time Can a Keller
unit remove emulsified oil from the coolant?
Any oil present as a stable emulsion in the coolant will pass
through the Keller system. (Incidentally, a Keller system
will not separate the coolant from water or change the composition
of the coolant.) Even the efficient coalescer in the Keller
unit can only accelerate the rate of separation of the oil.
However, zero multiplied by ten is still zero. The oil and
coolant must separate on their own in a reasonable period
of time for a coalescer to work effectively.
To determine the ability of the coolant to reject oil, take
a sample of the coolant in a clear container––for
example, a plastic water bottle––and let it sit. A
good coolant will reject oil as a layer on top of the sample
in a matter of minutes. If the sample sits for three days and
nothing happens, then the odds are that you will not be satisfied
with any coalescer. A coalescer cannot be used to “reclaim”
coolant which has been in the sump without treatment too long
and has completely lost its ability to reject oil.
How long will coolant last in a machine if properly maintained?
Typically a good coolant properly maintained should last a year
in the sump and still be in good shape. It is important to start
with a coolant that rejects tramp oil well. The better a coolant
rejects oil, the cleaner you can keep it, and the longer you
can run it.
Why does Keller
use only 1/2" air-operated diaphragm pumps on oil separators?
We have supplied pump/skimmers for many years, and we have units
in service in thousands of shops. Based on this extensive experience,
we have found that electric pumps (see below) and air-operated
pumps smaller than 1/2” inlet/outlet ports are much less
reliable than the more costly 1/2” air-operated pumps which
we use exclusively.
The 1/2” air pumps are self-priming, can lift 10 feet vertically,
and can be dead-ended or run dry without damage. If the filter
plugs and the operator does not change it, the pump simply stops.
The pumps are virtually indestructible. Since the pump is the
only moving part in the system, a rugged pump ensures trouble-free
operation for the customer, and peace of mind for Keller.
Why does Keller not offer electric pumps as options?
We are sometimes asked if we offer separators with the option
of electric pumps.
The answer is No.
Consider some of the operating requirements for pumps on pump/skimmer
units:
1) The pump
must be self-priming to lift the liquid from the surface
of the sump into the filter inlet. Self-priming electric pumps
are
expensive and susceptible to damage by small quantities of solids
in
the feed, obviously a major potential problem when pumping coolant.
An
electric pump could be submerged in the sump, but this is clearly
not
feasible for portable units and is cumbersome and maintenance-prone
for
dedicated units.
2) If the
prefilter plugs or there is an obstruction in the inlet
line, the pump will run dry. An electric pump will quickly burn
out,
while the air-operated pump will simply stop without damage
and start
up again when the inlet obstruction is cleared.
3) Even though
we supply a prefilter on each Keller separator, we
recognize that there is a possibility that metal chips can enter
the
pump if a replacement filter element or filter bag is not properly
installed. An electric pump, with close clearances, will quickly
sustain major damage, while the 1/2” air-operated pump
can run for a
moderate period without damage. Even if the situation is allowed
to
persist, any damage to the air pump diaphragms or ball valves
can be
easily fixed in the field with an inexpensive repair kit.
What are the
disadvantages of a belt or disk skimmer compared to a Keller
pump/skimmer?
1) Skimmers do not filter out solids.
2) Skimmers do not aerate the coolant.
3) Skimmers remove alot of coolant along with a small amount
of tramp
oil, adding significantly to the waste charges.
4) Skimmers are not particularly rugged and are susceptible
to damage
by solids pulled up with the oil and coolant.
5) Skimmers do not draw oil from remote areas of the sump.
6) Skimmers can operate only when the machine tool is idle.
7) Skimmer waste buckets frequently overflow, creating safety
and housekeeping issues.
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