System Operation

At startup, our is fed with a slurry and the concentrate valve is closed. Permeate is produced and suspended solids in the feed are collected inside our filter pack(s). After a programmed time interval, valve one 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. Membrane selection is the single most important parameter that affects the quality of the separation. Other 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 our system. Operating pressure is created by the feed pump. Our machines routinely operate at pressures as high as 1,000 psig (68.95 BAR). Higher pressures often produce increased permeate flow rates, but they also use more energy. Therefore, operating pressure that optimizes the balance between flow rates and energy consumption is used. In most cases, the filtration rate can be further improved by increasing operating temperature. The temperature limit on our System is 175° F (79°C), significantly higher than competitive membrane technology. We can create higher temperature constructions if needed. The vibration amplitude and corresponding shear rate can also be varied. This 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 seconds. Feed 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.