The
Gemini filter consists of a pressure vessel containing the
unique patented Gemini Filter candles. The candles act as fine
strainers and are used as the support (septum) for a deposited
bed of filter powder. This filter powder acts as the filtration
medium trapping the impurities from the fluid. At the end of a
run, reverse liquid flow removes the filter bed together with
the entrained impurities. The cycle can then be repeated without
opening the pressure vessel. With over 20 years of successful
operation behind it, the Gemini offers a reliable, cost
effective and proven filtration system for aviation fuels.
The units
available are - duplex to allow continuous operation, single
filter for batch processing e.g. tank to tank transfers and
portable units can be supplied for multi site operations. Flow
of up to 750 m3/hr per vessel are available for aviation fuel.
A typical
fuel pipeline installation has a twin filter unit, dosing vessel
and bag filter vessel. In operation while one filter is on
stream, the second filter is pre-coated and left in a prepared
state so that continuous filtration is achieved.
After
switching flow from one filter to the second the back-flushing
and pre-coat operations are carried out solely by the operation
of valves without the need to open the filter vessels. The spent
filter aid is then recovered using the bag filter thus
eliminating any loss of fuel and minimising the safety and
disposal hazards especially when compared to cartridge filters.
The
advantages of this design are as follows:
SUPERB
FILTERAID RETENTION
characteristics and high resistance to pressure surges as a
result of 40 micron septum pore size. RESISTANCE
TO SEPTUM BLOCKAGE owing to large
open area 38% of gauze.
CAKE
STABILITY(i.e. pre-coat retention
in no flow condition) resulting from the keying action of
the spiral wires.
RAPID
BACKWASHING capability.
HIGH
STRUCTURAL STRENGTH of 10 bar
differential pressure in the forward and reverse flow
directions.
ELIMINATION
OF MULTI PRE-COATS. In fact the
first pre-coat may be as fine as Dicalite grade UF or
equivalent.
Operational data shows
conclusively that the Gemini is the most effective filter for
returning out of spec fuel to meet MIL-T-831 33C for Filtration
Time and Total Solids specification.