& Services - Vibratory Shear
Enhanced Processing VMAT
[System Components] [Applications]
startup, the VMAT system is fed with a slurry and the concentrate
valve is closed. Permeate is produced and suspended solids
in the feed are collected inside the VMAT filter pack. After
a programmed time interval, valve on concentrate line is opened
to release the accumulated concentrated solids. The valve
is then closed to allow the concentration of additional feed
material. This cycle repeats indefinitely.
selection is the single most important parameter that affects
the quality of the separation. Other important parameters
that affect system performance are pressure, temperature,
vibration amplitude, and residence time. All of these elements
are optimized during testing and entered into the programmable
logic controller (PLC) which controls the system.
operating pressure is created by the feed pump. VMAT machines
can routinely operate at pressures as high as 500 psig (35
bar). While higher pressures often produce increased permeate
flow rates, they also use more energy. Therefore, an operating
pressure is used that optimizes the balance between flow rates
and energy consumption.
vibration amplitude and corresponding shear rate can also
be varied which directly affects filtration rates. Shearing
is produced by the torsion oscillation of the filter stack.
Typically the stack oscillates with an amplitude of 3/4 to
1 1/4 inches (1.9 to 3.2 cm) peak to peak displacement at
the rim of the stack. The oscillation frequency is approximately
53 Hz and produces a shear intensity of about 150,000 inverse
residence time is set by the frequency of the opening and
closing of the exit valve (valve one). The solids level in
the feed increases as the feed material remains in the machine.
Occasionally, a cleaner is added to the membrane stack and
continued oscillation helps clean the membrane in minutes.
This process can be automated and only consumes approximately
50 gallons (189 liters) of cleaning solution thus reducing
cleaner disposal problems inherent with other membrane systems.