PAINT RECOVERY TECHNOLOGIES INC.
WATER WASH SPRAY BOOTH
CASE HISTORY:
PAINT DE-TACK PROGRAM USING CENTRIFUGE AS THE SOLIDS REMOVAL
SYSTEM
ACCOUNT: Metal Ware Corporation - Manitowoc, Wisconsin
Manufacture "Nesco" Metal Roasting Pans
PAINT TYPE: High solids baking enamel, mostly black, with white and other colors.
Black is an acrylic/melamine resin and all others are polyester/melamine resins.
PAINT LOAD: Spraying 20 gallons of paint per day.
TRANSFER EFFICIENCY: 40%
DESIGN:
· Initial operation was a standard "E" Style water wash spray booth with a manual
centrifuge. A Company in Milwaukee, Wisconsin did original modifications to the spray
booth. These modifications involved trying to efficiently remove the paint particles.
However, they fell short of properly retrofitting the sump pan and directing the water flow
for optimum paint particle pick-up and suspension within the system until removed by the
centrifuge unit. Basically they placed a pump at the backside of the booth with a pick-up
point at the bottom center of the paint booth. This pump fed the manual centrifuge located
in a remote location approximately 15 feet from the booth.
· Three automatic paint spray guns are operating in a fixed position spraying the
product (pans). These guns are scheduled to "fire" well in front of the pan and continue
spraying paint until the pan clearly passes through the spray pattern.
· The pans are mounted on a pedestal on top of a conveyor chain. As the pans entered
the spray booth the pedestal's rotated for total paint coverage of each pan and it's lid.
PROBLEMS:
· Half of the paint over-spray was building up well short of the water on an extended pan
located directly in front and below the chain conveyor line. The operator was flushing this
mass of "live" paint with a hose at the end of the shift directly into the booth sump.
· Impossible for the polymer to de-tackify these "globs" of paint. Plugging of the upper
water spray manifold occurred, thereby releasing live paint solids up the stack and onto
the roof and into the surrounding neighborhood.
· Partially dead paint made manual centrifuge hard to clean resulting in the operator
letting the unit fill-up. Thus, not cleaning it until end of day. UN-removed paint solids
accumulated in paint booth falling into bottom areas of the pan, eventually filling booth up
with "sticky" paint sludge.
· Manual centrifuge filled up within two hours, making proper clean-outs impossible.
Centrifuge was drastically under-sized for this operation.
· High amounts of foam being generated from the high paint solids content in the booth
water. Large amounts of defoamer were required to control this situation.
· Booth had to be entirely cleaned-out every four weeks resulting in 4 operators working a
10-hour day on this unit, costly non-production time. Drums of "live" paint sludge were
generated - 18 drums to be exact - when accounting called for a crisis meeting. Drum
disposal of this sludge was $400.00 per drum.
SOLUTIONS:
· Added a short water flood sheet to the front of the booth directly below the conveyor
chain in order to catch all of the over-spray as an atomized paint particle.
· Replaced the upper standard metal pipe manifold with a new high efficiency PVC unit.
· Replaced the manual centrifuge with an automatic centrifuge.
· Re-tested paint kill and found that a sodium carbonate or sodium hydroxide alkalinity
base did not 100% de-tackify the paint molecule. Found lime (calcium hydrate) which is
the main ingredient along with a defoamer in Booth Compound 702, when used in
combination with Geo-Guard 9512, provided the desired 100% paint kill.
· Set-up chemical feed automation of Geo-Guard 9512 and Unite. Draw down tube
installed in-line with Geo-Guard 9512 feed pump in order to log pump output every day.
RESULTS:
· All over-sprayed paint entering paint booth water as an atomized spray paint particle.
No more "live" clumps of paint solids. No "live" paint particles up the stack.
· Quick and thorough de-tackification of all paint solids from improved manifold.
· Efficient timely removal of paint solids through automatic centrifuge. Only manual
labor requirement on unit is changing of sludge drum when filled. Sludge is relatively dry,
compact and with no solvent content is now landfill disposable at a very small cost.
· Booth is now cleaned-out once per year, yielding no drums of "live" paint sludge.
WATER WASH SPRAY BOOTH
CASE HISTORY:
PAINT DE-TACK PROGRAM USING CENTRIFUGE AS THE SOLIDS REMOVAL
SYSTEM
ACCOUNT: Metal Ware Corporation - Manitowoc, Wisconsin
Manufacture "Nesco" Metal Roasting Pans
PAINT TYPE: High solids baking enamel, mostly black, with white and other colors.
Black is an acrylic/melamine resin and all others are polyester/melamine resins.
PAINT LOAD: Spraying 20 gallons of paint per day.
TRANSFER EFFICIENCY: 40%
DESIGN:
· Initial operation was a standard "E" Style water wash spray booth with a manual
centrifuge. A Company in Milwaukee, Wisconsin did original modifications to the spray
booth. These modifications involved trying to efficiently remove the paint particles.
However, they fell short of properly retrofitting the sump pan and directing the water flow
for optimum paint particle pick-up and suspension within the system until removed by the
centrifuge unit. Basically they placed a pump at the backside of the booth with a pick-up
point at the bottom center of the paint booth. This pump fed the manual centrifuge located
in a remote location approximately 15 feet from the booth.
· Three automatic paint spray guns are operating in a fixed position spraying the
product (pans). These guns are scheduled to "fire" well in front of the pan and continue
spraying paint until the pan clearly passes through the spray pattern.
· The pans are mounted on a pedestal on top of a conveyor chain. As the pans entered
the spray booth the pedestal's rotated for total paint coverage of each pan and it's lid.
PROBLEMS:
· Half of the paint over-spray was building up well short of the water on an extended pan
located directly in front and below the chain conveyor line. The operator was flushing this
mass of "live" paint with a hose at the end of the shift directly into the booth sump.
· Impossible for the polymer to de-tackify these "globs" of paint. Plugging of the upper
water spray manifold occurred, thereby releasing live paint solids up the stack and onto
the roof and into the surrounding neighborhood.
· Partially dead paint made manual centrifuge hard to clean resulting in the operator
letting the unit fill-up. Thus, not cleaning it until end of day. UN-removed paint solids
accumulated in paint booth falling into bottom areas of the pan, eventually filling booth up
with "sticky" paint sludge.
· Manual centrifuge filled up within two hours, making proper clean-outs impossible.
Centrifuge was drastically under-sized for this operation.
· High amounts of foam being generated from the high paint solids content in the booth
water. Large amounts of defoamer were required to control this situation.
· Booth had to be entirely cleaned-out every four weeks resulting in 4 operators working a
10-hour day on this unit, costly non-production time. Drums of "live" paint sludge were
generated - 18 drums to be exact - when accounting called for a crisis meeting. Drum
disposal of this sludge was $400.00 per drum.
SOLUTIONS:
· Added a short water flood sheet to the front of the booth directly below the conveyor
chain in order to catch all of the over-spray as an atomized paint particle.
· Replaced the upper standard metal pipe manifold with a new high efficiency PVC unit.
· Replaced the manual centrifuge with an automatic centrifuge.
· Re-tested paint kill and found that a sodium carbonate or sodium hydroxide alkalinity
base did not 100% de-tackify the paint molecule. Found lime (calcium hydrate) which is
the main ingredient along with a defoamer in Booth Compound 702, when used in
combination with Geo-Guard 9512, provided the desired 100% paint kill.
· Set-up chemical feed automation of Geo-Guard 9512 and Unite. Draw down tube
installed in-line with Geo-Guard 9512 feed pump in order to log pump output every day.
RESULTS:
· All over-sprayed paint entering paint booth water as an atomized spray paint particle.
No more "live" clumps of paint solids. No "live" paint particles up the stack.
· Quick and thorough de-tackification of all paint solids from improved manifold.
· Efficient timely removal of paint solids through automatic centrifuge. Only manual
labor requirement on unit is changing of sludge drum when filled. Sludge is relatively dry,
compact and with no solvent content is now landfill disposable at a very small cost.
· Booth is now cleaned-out once per year, yielding no drums of "live" paint sludge.
Metal Ware Corperation "Nesco"
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