Proper Vacuum Cleaning of Powder Paint Booths - Crucial to Safety, Throughput, and Profits
The right vacuum cleaning system eliminates the dangers of
combustion, maximizes powder recovery and minimizes cleanup
time.
By Ed Sullivan
Although the powder coating process offers important advantages
that make it the finish of choice among manufacturers of industrial
and consumer products-beautiful cosmetic appearance, durability,
overall quality, and economies-the process also introduces health
and safety issues that make cleanup of powder coating booths far
more important than merely necessary housekeeping.
Worker exposure to inhalable particles, the possibilities of
powder combustion, and environmental damage are all potential
hazards that must be dealt with by manufacturers who use
powder-coating technology. While the basic requirements to minimize
these hazards are spelled out by OSHA and other agencies, it is
also clear that the avoidance of some risks can be determined by
the choice of an ancillary tool that is needed in the
powder-coating booth-the vacuum cleaner.
Some powder coating operations inadvertently use the familiar
"shop-type" vacuums to clean their powder coating booths. This is
especially common among manufacturers who are new to the powder
coating technology. While the "shop-type" vacuums may be
appropriate for some light-duty cleanups, they are generally unsafe
for use in a powder spray booth. Furthermore, the use of an
inappropriate vacuum cleaning system may cause the powder spray
operation itself to lose economies from the recovery and reuse of
overspray powder, and incur the added expense of having to dispose
of wasted powder.
"Combustion of powder coatings can occur when a deposited layer
of powder comes in contact with a source of ignition, such as
static electricity generated by ungrounded vacuum cleaners," warns
Steve LaFever, an engineer with Phoenix Wire Cloth, Inc., Troy, MI.
"Powder flowing in one direction through a vacuum-cleaning hose
will create a significant static electric charge. Plus, there is
the possibility that there is a static electricity build-up on the
powder coating deposits. If an ungrounded hose used to vacuum
overspray powder were to contact an object that was grounded, the
static electricity could then arc and trigger a violent
explosion."
Powder combustion has also resulted in raging fires that have
caused catastrophic damage to factory facilities and have resulted
in costly shutdowns.
LaFever says Phoenix Wire Cloth, which has manufactured wire
mesh and related product for over a century, wanted to purchase an
industrial-grade vacuum cleaning system to provide the needed
safety plus other important benefits to its powder coating
operation.
Phoenix Wire Cloth had converted its metal finishing process to
powder coating about five years ago. The company, which
manufactures a wide range of wire mesh-based products, such as wire
baskets, partitions, guards, cloth and security fencing, also uses
a wide range of metals to fabricate screen, including stainless
steel, bronze, aluminum, copper, tinned steel and high-temperature
alloys. The powder coat finishing process is applied to its safety
systems, including robotic enclosures, wire mesh partitions, stair
rail inserts, machinery guards and focal displays.
"We were a perfect candidate for powder coat finishing
technology, and a perfect candidate for a vacuum-based cleaning and
recovery system," says LaFever, who headed up the selection of a
new vacuum system last fall. The potential LaFever saw was for
faster turnaround on setups for new paint colors plus a certain
amount of savings by recovering powder overspray, as well as an
improved safety factor.
Phoenix Wire Cloth normally uses three basic colors in its
powder coat operation, although special colors and clear-coat are
also available. Each time a color change is required, the powder
spray booth has to be cleaned and overspray must be vacuumed out of
the spray booth. Some products, such as safety fences, receive two
or three different colored fences, but otherwise, powder colors are
changed at intervals subject to sales orders.
"The safety fences that we manufacture are powder coated in a
rather small booth, approximately 3 ft. by 12 ft.," LaFever
explains. "And we have limited space available for an additional
powder coating and baking facilities. So, by speeding up the
cleanup process, we are speeding up overall productivity for
powder-coated products." One of the ways cleanup time could be
improved was to make sure that a squeegee was integrated into the
vacuum system. There was also a likely substantial saving in labor
over the old method, which included a "shop-type" vacuum and wipe
down of the spray booth by hand.
Because color changes occur on an as-needed basis, it is hard to
say how much money the company was likely to save through recovery
and reuse of powder overspray. LaFever was aware that recovery was
often a significant factor in powder coat operations, so he decided
that the new vacuum system should have separate recovery canisters
for different powder colors. Not only would that enable reuse of
the powder, but would obviate the need to treat the powder as
hazardous waste - another savings.
Once the vacuum cleaning system specifications were decided,
Phoenix Wire Cloth sought bids from several suppliers.
"Surprisingly, there was a wide range of prices, and varying
apparent interest among vendors," LaFever says. "Among others we
contacted Heneveld Group in Zeeland, MI, because of an article I
read in a trade journal about a vacuum system they distributed.
The system that Heneveld represents is VAC-U-MAX, a premier
brand in the vacuum cleaning and conveying industry. Although
VAC-U-MAX did not offer the lowest cost products, they did offer a
wide range of solutions, including one that Phoenix Wire Cloth
would meet all its specs at the best price.
"The system we ultimately selected was a standard VAC-U-MAX
'workhorse' model, a portable 55-gallon unit with changeable
collection containers," LaFever says. "The VAC-U-MAX system is
completely grounded, so there is no danger of an explosion or fire
resulting from static discharges during vacuum clean-up operations.
The system is quite powerful and includes a wand and squeegee, so
we can clean the walls and floor of the spray booth much more
quickly. We purchased three collection canisters, which allows us
to recover our three basic colors in separate containers for later
reuse. Basically, the cleanup operation is now just a matter of
blowing out the hoses and vacuuming the powder."
LaFever says that the most meaningful savings with the new
VAC-U-MAX cleaning system is on labor, although productivity
improvements and powder recovery should also prove to be
substantial. "With the material savings, the savings will mount up,
but it's actually relative to the number of times we change color
in the spray booth. We may be running a color for four days before
we have to make a change, then need to change color again within a
day. So, material savings will be a function of how often we have
to clean up the stray booth. As for the risk of static electric
discharge, we are confident that it has been minimized," LaFever
says.
VAC-U-MAX offers the industry's only written static control
guarantee which is provided with its Venturi compressed air-powered
vacuums with anti-sparking vacuum inlets and grounding lugs.
Optional stainless steel anti-sparking construction of the cover,
suction inlet, and all internal contact parts, excluding the
filter, can now minimize the possibility of sparking resulting from
dynamic contact between the suction inlet and particles drawn into
it. Static conductivity from end to end, including a static
conductive hose with internal ground wire and grounded end cuffs,
further prevents static build up.
Together these measures safeguard the cleanup of excess powder
from fires or explosions related to static discharge or accidental
electrical ignition. Optional static-conductive filters, rated
99.9% efficient at one micron, further reduce sparking danger,
while virtually eliminating any fine particle discharge from the
vacuum's exhaust back into the work area. This ultra-fine
filtration helps to create healthful, productive breathing
conditions in the workplace.
David Kennedy, Sales Manager for the VAC-U-MAX vacuum cleaning
product line, says powder-coating operations are a very popular
application for VAC-U-MAX systems. "We have customers who have the
need for the same functionality and benefits as Phoenix Wire Cloth,
and some who have other needs. For example, some customers need a
vacuum cleaning system that can support continuous operation, so
that powder is cleaned up before it can be transported on conveyor
belts that carry freshly coated products. Some want
electric-powered systems, others require air power. Certain
operations are concerned with noise or need certain accessories or
adapter devices. Whatever their need, we feel it is vital to offer
them the right system and components."
VAC-U-MAX systems are sold worldwide, with major markets for
vacuum cleaning systems including the metalworking, chemical, food
and pharmaceutical industries. Industrial vacuum cleaners range
from small air- and electric-powered drum-style units to large
electric and diesel units offering a choice of discharge into
drums, bulk bags, hoppers or roll-off containers. Centralize unites
can hook up to fixed piping networks or clean out silos. Options
include continuous dual-pulse filter cleaning, HEPA filtration,
custom control packages, intercept hoppers. Standard airflow ranges
are between 100 CFM and 1000 CFM.
For more information about VAC-U-MAX industrial vacuum cleaning
or pneumatic material handling solutions, contact VAC-U-MAX by mail
at 37 Rutgers Street, Belleville, NJ 07109; telephone (800)
822-8629 or (973) 759-4600; E-mail: info@vac-u-max.com; or visit
the web site www.vac-u-max.com.