Over 300 Prayon tilting pan filters have
been sold since the 1950s, and approxi-
mately 250 installed in phosphoric-acid
production units. The rest are used in
other fields such as:
Copper, cobalt, zinc and uranium hy-
-impregnated active carbonwashing;
Phosphate washing;
Acid filtration in general.
Main developments
A special compact vacuum box for sepa-
rating gases and the various filtrates;
A fast-drain filtration cell (pan) which
can increase filter capacity and filtra-
tion yield;
An automatic system to keep the pans
A new tilting-track design for higher
rotation speed and filtration capacity;
Support rollers designed for heavy
A robust rotating frame with a replace-
able wear plate;
A new waterproof cloth-fixing system
meaning that the cloth can be replaced
in a very short time;
A high filtering surface to base area
Main benefits
High level of reliability due to their ro-
bust design; indeed, a number of filters
sold in the 1960s are still in operation;
On-stream factor of over 95%;
Excellent capacity / extraction yield
ratio, due to batch filtration and a high
authorised maximum vacuum level;
Extremely energy-efficient;
Negligible recycling of the solids re-
covered during cloth washing, meaning
that the cake discharged from Prayon
filters contains very little free water;
Able to benefit from Prayon’s proven
track record with very large filters (e.g.
30-240 filter with a surface area of
275 m²).
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