Finishing - May-June 2023

38 CLEANING
Extra large blast
Guyson International has installed a
Guyson Euroblast 2-metre PF (Pressure
Fed) blast system into a division of a
leading European aerospace company. The
extra-large blast cabinet is used to deliver a
uniform etched key surface on a range of
machined circular aluminium rings prior to
bonding.
After blast trails performed at the
company’s Skipton demonstration centre, a
Euroblast 2-metre PF blast system (2.1 m deep
x 2.5 m wide internal cabinet) was specially
designed by their engineering team to
provide a side loading and forward tilting
turntable which can accommodate rings up to
1.8 m diameter and a 20 kg load. The side
loading scissor lift design permits the load
table rails to be lowered, once the tilting
turntable has been manually pushed into the
blast chamber, allowing the full height cabinet
side door to be tightly closed creating a seal
to prevent dust and media escaping during
the blast operation.
The external frame also allows components
to be loaded outside the cabinet using a crane
or hoist where necessary and is fitted with
blast media catch trays and hopper to contain
and collect any spent media, for a cleaner and
safer working environment.
Blast etching of the aluminium rings takes
place within the blast chamber, with the tilting
turntable allowing the components to be
vertically raised directly in front of the
operator’s eye line. This enables enhanced
parts visibility, easier manual rotation of the
turntable and better line-of-sight blast access
to the rings.
Internally mounted roof and forward
bulkhead lighting, coupled with light coloured
rubber curtain lining which provides cabinet
protection and good contrast for parts
visibility, ensures excellent shadow free
visibility through the two operational viewing
windows during blasting. Two sets of wide
armhole sleeves provide the operator with a
choice of operating positions; along with
greater flexibility to blast all around the
circular components.
A 55-litre capacity pressure pot is used to
generate the blast stream within the blast
chamber and when the full-width foot pedal
(which can be operated by either foot) is
depressed it pressurises the pot and starts the
blast operation; similarly releasing the pedal
de-pressurises the pot and stops the process.
Blast media is fed from the pressure vessel
into the cabinet through a heavy-duty hose to
the boron carbide blast nozzle. The flow of
media is controlled by a manual pinch valve
mounted on the cone of the pressure pot; this
regulates the volume of media being released
into the compressed air stream. After blasting
a trigger operated air wash gun removes
residual dust and blast media from the rings.
After extracting everything from the bottom
of the blast cabinet, the cyclone reclamator,
located in the tower above the G55 pressure
pot, separates reusable blast media from dust,
debris, and undersized media. By drawing the
lighter particulates to the dust collection unit
and returning the heavier re-usable blast
media to the pressure pot, contamination by
abraded particles and debris is greatly
reduced, thus making the surface finish more
consistent.
The whole blast system is completed with a
Guyson C800 twin cartridge filter dust
collector, a highly efficient unit for filtering out
and collecting the dust-laden air from the blast
cabinet. The heavier extracted particles being
deflected downwards towards the collection
bin, the lighter particles are captured on the
surface of the filters. Any small pieces of
debris removed by blasting are captured by
perforated steel floors in the blast cabinets
hoppers, thus reducing blockages in the blast
hose/blast gun.
Finishing - May/June 2023