ROTARY PRECOAT FILTRATION Although rotary precoat vacuum (and pressure) niters have become more and more a factor in nitration, there has been no test device available for the systematic study of nitration rates, nlteraid requirements and all the other pertinent operating variables in precoat nitration. Test leaf niters have been used, it is true, but the lack of a precisely controllable shaveoff mechanism, among other things, has limited their usefulness and severely restricted the extension of their results to actual plant scale nitration. Full plant scale tests, though often impractical from the standpoint of time and expense involved, have hitherto been the sole method of working out, accurately, all the variables in establishing optimum performance of precoat niters at the lowest cost. Only those who have struggled with such a test can appreciate the tremendous difficulties in this work. Yet the potential savings in improved operations are so great that a solution of the problem has become imperative. We believe that the newlydeveloped, laboratory-scale Dicalite Rotary Precoat Filter Test Leaf, described at the June meeting of the A m e r i c a n I n s t i t u t e of Chemical Engineers, in Seattle, goes a long way toward such a solution. This device takes its place as a companion t o t h e well-known Dicalite 'Bomb' Filter, developed earlier for studies in pressure filtration, and widely used for research and control in industrial plants, by filter manufacturers, and in the laboratories of industrial and university research groups. The new Dicalite filter test leaf is already finding application in the determination of most efficient operating procedures for existing rotary precoat filter installations, and in studies to determine the possible advantages in potential applications. If you have problems involving rotary precoat niters, Dicalite field service engineers will be glad to advise with you, and to discuss the application of this new filter test leaf to the solution of these problems. Filter manufacturers' representatives will soon have this new Dicalite test unit to assist them in their work.
-A.n avenue opens to ne^w answers in
filtration
iltration studies never possible before except on a pilot plant scale a r e now made quickly, inexpensively and more accurately t h r o u g h a n e w development of Dicalite research. This device, a r o t a r y precoat filter t e s t leaf, is t h e first precise a n d practical laboratory-scale device available for study of t h e process variables in r o t a r y precoat filtration. W i t h it, complete tests of all t h e major variables can be m a d e in a few hours with a few gallons of process liquor. A long series of these tests h a s demonstrated t h a t t h e results obtained w i t h the Dicalite R o t a r y Precoat F i l t e r Test Leaf show close agreement with those subsequently obtained in full-scale plant operation. Tremendous possibilities a r e t h u s opened u p t o processing people by t h i s latest Dicalite contribution t o t h e advancement of filtration technology. For further
Dependable GLC IIEtT
LAKES
information
please
write:
Dicalite® DI A T O M A C E O U S
MATERIALS
Paul W. Leppla, Technical Director (ADVERTISEMENT)
DICALITE DEPARTMENT, Great Lakes Carbon Corporation, 612 South Flower St., Los Angeles 17 For further information, circle number 29 A on Readers' Service Card, page 101 A VOL. 49, NO. 8 ·
AUGUST 1957
29A
