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At the beginning of the ‘80ies,
in the United States, the South Coast Air Quality Management
District (SCAQMD) in Los Angeles and
other bodies charged to check air quality, were troubled by
the damage organic volatile chemical substances (VOC)
caused to air quality. They issued strict regulations which
set the minimum transfer efficency of painting guns to 65% at
a pressure below 10psi (0.70bar). The more the product could
reach the surface to be painted, the less it was wasted and
dispersed in the air.
Because of the new standards, the leading manufacturers of
high pressure guns had to find a solution to increase the
efficiency of their products where the transfer capacity was
notoriously poor. As a consequence, they conceived guns that
could convert the high pressure air supplied by compressors
into low pressure air.
These guns called HVLP
(high volume low pressure) could fulfil all
legal provisions with the sole restriction of using a min.
10 hp compressor because air consumption was higher than 20 cubic
feet per minute (cfm).
The HVLP turbine spray gun was developed
to meet market requirements.
The system is using a small but powerful turbine that can
deliver a high air flow through a tube in order to supply
the spray gun that can provide for a transfer capacity above
65% and, in special cases, even above 85%.
Every single component – turbine, tube and spray gun – is
playing an important role in the whole system.
The demand for this compact and light equipment is constantly
increasing in consideration of the tendency to limit polluting
emissions for environmental protection in many countries.
A tendency also confirmed by varnish producers orienting
part of the research / development towards the creation of
more “ecological” products,
such as water-based or solid content products (with a low
content of solvents) that can however give good application
results. |
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