by Ron Joseph
January, 2005
Cleaning Spray Booth Filters
Q. Congrats on your site. I come across it from time to time when trawling the
web for various things. Should stop a while and pay more attention. You obviously
have vast experience in the field.
My company is the largest yacht painting contractor in Australia. It grew
from a one-man (me) band over 30 years or so & as a result we still carry
a few 'backyard' traits in our corporate DNA.
Anyhow, we maintain a (self-built) tunnel booth for painting small parts
off the yachts. It's a simple cross-draft set-up (It WAS properly engineered
incidentally) with intake filter in one end. The other day I happened to notice
an employee using high pressure air from the outside to clean the intake filters.
My first thought was "this can't be right" and my second was "how
come we don't have a procedure for this". Then I thought "How WOULD
one clean these filters?" and finally "CAN they be cleaned?"
I cannot find any useful reference to this subject anywhere. The filter panels
are a thick nonwoven fabric and since the booth runs day & night in an industrial
location they do collect a fair bit of dust.
Do you have any suggestions as to how (& IF) they can be cleaned and
how often this should be carried out? It's somewhat easier with exhaust filters
to determine that they are 'loading up' but less so with intake filter.
Needless to say, I made a point of going to check the parts painted in the
booth right after the aforementioned 'cleaning' and found them unacceptably
dust contaminated (particularly as they are off a 200' motoryacht worth $100M
!).
Any input would be gratefully received.
A. Nice to hear from you all the way from the Southern Hemisphere.
Frankly, I have not seen anyone clean spray booth filters, with the exception
of the inexpensive expanded polystyrene filters that are intended to be reused.
With the latter you can scrub them clean with a bristle brush, but they are
so brittle that they can break quite easily.
For all other filters I have never seen a reference to anyone cleaning them.
They are almost always disposed of. To cut the cost of filters, we usually recommend
purchasing a two- or three-stage system. The first stage has a more open mesh
and captures the larger particles, while the smaller ones are captured by the
second stage panel or pocket filter. If you purchase a third stage, it will
capture the really small particles <10 microns.
Because stages two and three are expensive (stage three is very much more expensive
then the second stage), the goal is to replace the first stage frequently. Stage
two is replaced less frequently and the third stage is replaced every 6 months
or so, depending on its loading.
I hope this helps.
Best wishes,
Ron Joseph
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