REMCO ENGINEERING ENVIRONMENTAL WATER SYSTEMS AND CONTROLS
REMCO ENGINEERING
ENVIRONMENTAL WATER SYSTEMS AND CONTROLS
Question and Answers on Scrubber
Recirculation.
Q. What are the benefits in using a scrubber
recirculation system?
A. There are two main benefits, water use reduction and reduced
copper loading on the wastewater treatment system. Recirculation
of a scrubber or deburrer will save 6 to 10 gpm when that system
is on. That is less water to buy, treat, and pay sewer tax on. If
you only run you scrubber for 3 hours per day, 5 days a week,
that is (at 8gpm) 360,000 gallons per year. If you run 2 systems
at 8gpm each, 4 hours/day, 6 days a week thats 1,152,000 gallons
per year.
The reduction in copper loading on the waste water treatment
system results from the capture of all of the copper you used to
just dump into the drains. When you dumped it into the drain, the
low pH of most systems just dissolve it and make you remove it in
your wastewater treatment system. If you dumped it into the drain
with chelated rinses, you just saturated the chelates with copper
and made more headaches for yourself. Even small shops can
generate several pounds of Copper per day from
scrubbing/deburring operations.
Q. How clean is the water being
recirculated.?
A. In pumice or copper only applications, the effluent water
after filtration is clear. When you take a sample in a glass,
there is no visible sediment. We do not plug nozzles.
Q. Can I run more than one scrubber on a
single system?
A. Yes, we have an oversized version that can supply up to 20 gpm
at a small increase in cost. The limiting factor is the length of
the return lines from your scrubbers to the system. Gravity
feeding back to the recirculation system is only effective over
short distances. A sump pump will be necessary if one of the
scrubbers is not near the recirculation system.
A second consideration is chemical compatibilty of the two
scrubber/deburrers. If one is scrubbing tin/lead and the other is
scrubbing electroless copper, when the pH is low, you may have a
problem. If both are copper applications, it should be acceptable
to run both systems on one recirculation unit.
Q. How much pressure can I get from the
recirculation system?
A. The type of pump we use can generate up to 110 feet of head
(about 45 psi) We generally run about 35+ psi at your nozzles
with flows up to 20 gpm.
Q. My maintenance guy doesn't want to lean
over into your enclosure to empty the bag filter, can I get
another configuration?
A. Yes you can, two in fact. We can mount the bag filter
externally to the system so it is easier to service or we can
mount the whole system on a fiberglass skid to make service much
easier for all components. The fiberglass skid configuration is
slightly less expensive than the polypropylene system. We can
also make the bag filter larger so emptying is less frequent in
high volume shops.
Q. Why is your system better than all the
others on the market?
A. Ours is the first fully automatic system that both eliminates
nozzle plugging solution and has high capacity. The combination
of the cyclone and switching media depth filtration results in
very complete particulate removal. Careful consideration has been
give to all of the components in the system to provide a complete
package with no weak points. Designing for pumice applications is
the most difficult challenge in this industry because pumice
causes everything to wear out rapidly. We have carefully selected
the pump, valves, and other components for their ability to
withstand the environment and for their low cost and ease of
replacement when the pumice does get to them. If you don't use
the system with pumice, the life of the components extends
dramatically.
Q. How long will the components last between
replacement if we use pumice?
A. With continuous use (24 hours/day) we see valve diaphram
replacement at 9 months to a year. We are working with other
vendors for polyurethane diaphrams for longer life. The pumps are
sealless, bushingless and seem to last at least 2 years before
the impellers wear out. The cyclone itself can last up to 2 years
providing the pH is neutral. Running the system at low pH will
shorten the life of the components dramatically.
Q. Can't I just use a bag filter and a pump?
A. Of course you can. This works well for many people but you
will notice that the water is always Copper colored and if you
look inside your scrubber, the system is coated with copper. Your
flow rate will drop as your bag filter fills up and you will not
have anyway of knowing how well you are rinsing your panels. You
will have periodic nozzle plugging that your operators don't
notice unless you have good PM. We found one system that had half
of the nozzles plugged and the operator had never noticed because
one or two sprays will obscure the window and you can't see
anything. The maintenance cost savings alone usually justifies
our system. We alarm the bag filter for either backpressure or
flow so when it is time to empty it, you will be notified. The
usual bag filter systems are run until nothing comes out of the
nozzles in the scrubber.
Q. What types of systems are available?
A. The main difference between the systems on the market are the
level of maintenance required to keep them running and the
particulate size in the returned water. Systems with cyclone
separators separate the larger particles but not the small one.
Small particles can bunch together and clog nozzles also. Bag
filter type systems filter particulates down to a small size but
effluent water is still not clear and the bags clog quickly. Some
vendor recognize this and have bag filter arrays which you get to
clean regularly. Nozzles still plug and the flow is restricted as
the bags fill up. Continuous vaccum filters use a filter strip to
separate Copper fines from the water but the recirculated water
is always a copper colored solution which indicated the high
level of copper fines still in solution.
Q. How can it tell which system is best for
me?
A. Call a customer of the vendor and ask them three things:
Q. How often will I have to replace and haul
the media from the filters?
A. The filtration media is "permanent". We get some
losses when we backwash. Every year or so, some should be added
to the system to allow for backwash losses.
Q. How much maintenance will I have to do on
the system?
A. The only routine maintenance on the system is to answer the
alarm and clean out the bag filter. There is an air purge on the
bag filter to empty it of water which makes it easy to remove the
bag. All other components do not need service except that some
makes of pump motors may need bearing lubrication.
