I/EC Brief Ind. Eng. Chem. SO, 829-36 (1958)
Experimental Determination of Velocity Profiles in an Extruder Screw Using a screw e x t r u d e r with a glass sleeve a n d a t r a n s p a r e n t fluid containing a l u m i n u m particles, local velocities relative to t h e screw w e r e d e t e r m i n e d with a microscope in an axial section of t h e groove. M e a s u r e m e n t s w e r e m a d e for maximum, i n t e r m e d i a t e , a n d n o o u t p u t . Velocity vectors a r e divided into two components: t a n gential a n d b i n o r m a l to t h e helix. T h e former is directed t o w a r d t h e e x t r u d e r h e a d in maximum flow, "while its direction in t h e o t h e r two cases d e p e n d s on t h e d e p t h coordinate of t h e point whose velocity is b e i n g considered. T h e b i n o r m a l c o m p o n e n t was i n d e p e n d e n t of tangential flow, so t h a t its distribution r e m a i n e d t h e same in all conditions. It causes a circulatory motion t r a n s v e r s e to t h e groove a n d therefore a mixing action. I n t h e n o - o u t p u t condition t h e two components become zero at two t h i r d s of t h e height of t h e groove, t h u s causing a stationary layer. SILVIO ECCHER and ALDO VALENTIONOTTI Pirelli Società per Azioni, Milan, Italy.
I/EC Brief Ind. Eng. Chem. 50, 837-48 (1958)
Steady-State Longitudinal and Radial Temperature Distributions in Internally Heated Finite Wires T h e differential equation for t h e steady-state simultaneous longitudinal a n d radial t e m p e r a t u r e distributions in electrically h e a t e d finite cylinders with e n d s at t h e a m b i e n t t e m p e r a t u r e has b e e n set u p a n d solved for variable Q a n d constant h a n d k. T h e effect of variable h o n t h e longitudinal g r a d i e n t is shown for variable Q a n d constant k. Radial t e m p e r a t u r e gradients w e r e c o m p u t e d u n d e r several assumptions. Example calculations a r e p r e s e n t e d for comparison. A m e t h o d of selecting a desirable test section l e n g t h for p r e d e t e r m i n e d mid-cylinder a n d test l e n g t h e n d t e m p e r a t u r e s is given. A m e t h o d is given for estimating t h e mid-length t e m p e r a t u r e from a m e a s u r e d m e a n t e m p e r a t u r e a n d o p e r a t i n g conditions.
accurately CHEMICAL DEHYDRATION controlled
withdewtUhv Qanov-Ή muusTP/A Here are t w o new ovens, proven in the field, that were developed especially for chemical dehydration and other processes that require larger air vol ume than normally found in standard ovens. Built-in exhaust fans can be regulated to control flow of air and will operate a u t o m a t i c a l l y a t pre-set times. THE DESPATCH V-39, a truck-loading, batch type oven, has proven itself in the chemical drying field. At Diamond Alkali Comp a n y ' s Painesville, O h i o plant they're reducing the moisture content of chromium chemicals from 1 5 % to no more than 4 % and holding it there. A 2-hour bake at 500°F does the job thoroughly ! Investigate the Despatch V-39 or V-41—you'll discover that they offer the large v o l u m e h o r i z o n t a l airflow that maintains exceptional temperature uniformity.
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