A plate-and-frame filter press operating at a constant P of 150 psi is to be used to filter a sludge containing 2 lbm of solids per ft3 of water. The filter must be disassembled and cleaned when the...

A plate-and-frame filter press operating at a constant P of 150 psi is to be used to filter a sludge containing 2 lbm of solids per ft3 of water. The filter must be disassembled and cleaned when the cake thickness builds up to 1 in. The frames have a projected area of 4 ft2 , and the downtime for cleaning is 10 min/frame. The properties of the sludge and cake were determined in a lab test operating at a constant flow rate of 0.2 gpm of filtrate, with a filter area of 1/4 ft2 . The test results show that the pressure drop rises to 3 psi in 20 s and to 8 psi in 60 s. Calculate the overall net filtration rate per frame in the filter, in gpm of filtrate, accounting for the down time. The density of the cake was found to be 150 lbm=f t3 .