Canadian Finishing & Coatings Manufacturing - Sept/Oct '23 - 34

PLATING AND ANODIZING: PUMPS AND FILTERS
Digital power monitoring is now integral to
advanced VFD controllers, providing a noninvasive
and precise/linear means of safeguarding
process pumps against adverse
operating conditions.
contamination, etc.) as media pressure drop doubles, pore
structure is used up by 50 per cent. Therefore, a low starting
pressure drop <1.0 PSID requires less than 10 PSID to
maximizes media life. Other benefits include a lower surface
layer density that serves as a filter aid to achieve finer
filtration.
Target flow rates of 0.5 - 1.0 GPM per square foot of media
will substantially extend filter life and changeout intervals.
Using high performance media filters or high efficiency
BETA rated media particle removal (i.e., single pass retention)
optimises the probability factor by removing contaminants
with >99 per cent efficiency ratings to avoid having to refilter
the same contaminants.
Filtration Application Data
Filtration Affinity Rule No. 1: Media life within the same
process conditions (e.g., comparable bath chemistry,
production volume, flow rate, micron ratings, media flow
characteristics, etc.): Doubling media surface area will
quadruple life.
Filtration Affinity Rule No. 2: Following the same
exponential factor, media life predictability can be determined
as follows:
* As media pressure-drop doubles (at clean start-up) life is
reduced by 50 per cent.
* Verifying Media Pressure Drop: Confirm start-up media
pressure drop by checking the pressure at the filter vessel
(before and after installing media) to determine the increase
in pressure.
Therefore, undersized filters and low-porosity media will
require excessive start-up pressures that will never achieve
the maximum filter life due to one of the following limiting
factors:
* The required pressure rise will exceed the pressure
capability of the media, housing, or pump.
* The excessive filter pressure drop will diminish pump
capacity below the minimum bath turnover rate.
A low start-up media pressure drop of 1 to 2 PSID (or less)
will significantly increase solids holding capacity due to
the lower density surface layer. Maximum filter life will be
achieved, well within the performance limits of the media,
filter housing, and/or pump.
Excessive pump flow in a runout condition (e.g., low head)
leads to cavitation. Also, tank agitation that can disrupt
sensitive baths such as Activator/Palladium and E-Nickel in
POP processes.
Pressure drop with a D.E.-carbon pack is typically higher
than carbonless filtration due to the blinding nature of
powder carbon.
34
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Low Pressure Drop and Lower Pump Head
Proper filter sizing and more efficient filter media reduces
the need for pump head pressure to overcome those losses.
Therefore, further speed reduction is possible in the range
of 40-45 Hz that can be the predominant operating range for
many weeks while the media is gradually loading with a lower
surface layer density.
VFD Energy Savings
Pump power curves reduce cubically so the energy saving HP
coefficients with the same impeller size are:
* Annual Savings Per HP @ $315.00
* 60 to 50 Hz = 0.569X or $136.00 per year (per 1 HP) or 43
per cent savings
* 60 to 40 Hz = 0.287X or $225.00 per year (per 1 HP) or 71
per cent savings
* 50 to 40 Hz - 0.50X or 157.00 per year (per 1 HP) or 50 per
cent savings
VFD Pump Power Monitoring
Digital power monitoring is now integral to advanced VFD
controllers, providing a non-invasive and precise/linear
means of safe-guarding process pumps against adverse
operating conditions, including dry running, dead-heading
or operation below minimum turnover rates, cavitation or
" pseudo-cavitation " (i.e., entrained air, suction leak, vortex,
etc.) and spent filter elements in a filtration system.
High load sensors can detect:
* Excessive flow
* Run-out condition due to insufficient head (e.g., overstated
head, " fudge factors, " discharge pressure drop, etc.)
* Initial onset of cavitation (e.g., low NPSHa, low suction
head, vaporizing liquid, etc.)
* Flow restriction (e.g., plugged suction filter or strainer,
partially closed suction valve)
* Pseudo-cavitation (i.e., entrained air, vortex, suction leak,
etc.)
* Interference or obstruction within the pump
Low load sensors can detect:
* Minimum flow
* Dead-heading
* Flow restriction (i.e., plugged discharge filter or strainer,
clogged spray nozzles, closed discharge valve, etc.)
* Dry running
* Vapour lock
Joseph Warrender is the president of Warco, Inc., a provider of
advanced filtration and pumping systems. He can be reached
at joseph@warcoinc.net.
Editor's Note: Achieving energy savings through dialed in
pump and filtration processes is a hot topic among equipment
suppliers. The energy savings calculations are very specific
to the cost per kilowatt hour in different regions. Reach out to
Warco, Penguin Filter Pump, Hendor or any preferred pump
and filtration equipment supplier and they will be happy to help
calculate such costs and savings and troubleshoot processes to
achieve greater efficiencies.
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Canadian Finishing & Coatings Manufacturing - Sept/Oct '23

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