SPECIAL FEATURE
What's so special about a SPERRY FILTER PRESS?
ANSWER: Your special
needs!
Equipped with any type of plates — center, side or corner feed — open or closed delivery—to filter liquids, recover solids, or de colorize—yourSperry Filter Press is engineered to your particular requirements. Not only for to day's schedule — but for the un foreseen changes of tomorrow. When c o n d i t i o n s r e q u i r e a change in media —in capacity — in material — your Sperry Filter Press offers the built-in versatil ity to supersede itself. It's the best investment you can make in a dependable and rugged filter press. D. R. S P E R R Y & C O .
Batavia, Illinois SaJes Representatives George S. Tarbox Alldredge & McCabe 808 Nepperhan Ave. 847 E. 17th Ave. Yonkers, Ν. Υ. Denver, Colorado Texas Chemical Eng. Co. The Gilbert Tramer Co. 4101 San Jacinto 1217 Main Ave. Houston, Texas Cleveland, Ohio Β. Μ. Pilhashy (Successors) Galloway-Ratcliffe, Inc. I l l Sutter St. 4053 Lindell Blvd. San Francisco 4, Cal. St. Louis, Mo.
trivial saving on a per unit basis can a d d u p to substantial a m o u n t s . A good p r o g r a m ensures t h a t no oppor tunity for improvement is overlooked, no m a t t e r how great or small the gain. E V O P is not r e c o m m e n d e d where a process is supported by a d e q u a t e theoretical knowledge. It is an empirical tool a n d represents the Edisonian approach. I n fact, this is the power of E V O P . W h e r e suffi cient fundamental knowledge is lack ing, the process engineer need not wait until the undefined point has been developed. H e can proceed immediately to adjust operating variables for at least improving, if not optimizing, factors such as yields or costs. E V O P thrives on a sense of urgency. It is an ideal tool for the impatient engineer who is not satis fied with his process and hopes to make improvements while waiting for more fundamental information to be developed. Sometimes E V O P m a y a p p e a r to fail—most techniques d o — a n d there is always the risk of improper use. It will not ferret out the i m p o r t a n t but u n k n o w n and untested variables. Proceeding first with a fractional factorial experiment for screening im p o r t a n t variables will not help either, unless the variable is tried. O n the other h a n d , there are m a n y examples of success where E V O P was not entirely applicable, and even where the process was not u n d e r statistical control. These cases should be looked at as less a test of E V O P t h a n as taking a calculated risk of failure. E V O P techniques minimize that risk. Actually, E V O P techniques are not too different from those used in the old days. T h e n a good super visor or foreman often tried m i n o r modifications on a trial and error basis, using the good trials a n d discarding the failures. EVOP makes these trials systematically a n d provides a basis for good j u d g m e n t about the effects.
D. R. SPERRY & CO. Dept. IEC-12 Batavia, Illinois
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In practice, E V O P has been a p plied to problems involving factors such as increased yields, lower r a w material requirements, or recycle time. However these factors are e p h e m e r a l — t h e process m a y not be
Circle No. 63 on Readers' Service Card 42 A
INDUSTRIAL AND ENGINEERING CHEMISTRY
in operation next year or even to morrow. Therefore the real a d vantage of the technique is t h a t it promotes a new way of thinking, a n d utilizes to its fullest extent the h u m a n factor. For example, the r e m a r k of a youthful assistant superintendent of a large plant is revealing. H e said, " T h e old m a n is a little on the con servative side . . doesn't want to fool around with the process. With E V O P now, I can propose certain studies and there's not m u c h h e can d o but to go along with the idea. This is great for us young guys." I n his first study, this y o u n g en gineer upset two long-held fallacies about the process. Experience has shown t h a t E V O P tends to have a catalytic influence on the m e n t a l activity of plant per sonnel. T h e r e is an instance of a superintendent w h o instituted an E V O P p r o g r a m and then in a mood of experimentation decided to try, without benefit of E V O P , a process change he h a d been wondering about. His move was a gamble, but it paid off handsomely in lowered production time, increased capacity, a n d reduced process costs in other areas. This stimulation for original think ing is not by any means limited to the superintendent or his assistant. O p e r a t o r s seem to be affected too, a n d with greater interest in the proc ess, they are likely to exercise closer control. E V O P is a break in the rou tine with something to look forward to. And, possibly another factor enters the picture as well—in eliciting operators' assistance, m a n a g e m e n t provides them, with a feeling of greater i m p o r t a n c e . M a n does not live by bread alone. O t h e r personnel in the plant hier archy are influenced as well, such as process engineers, quality control personnel, and those taking p a r t in E V O P committee deliberations. T h e p r o g r a m provides a n oppor tunity for individuals to present their views for consideration. D o w Chemical like m a n y other organizations has an operations im provement ( O I ) p r o g r a m . As a re sult, the employees have become so O I conscious that a janitor m a y sub mit a proposal. His suggestion m a y not be earth-shaking, but it adds to the p r o g r a m a n d bolsters the m o r a l e of the janitor.
