INSTRUMENTATION

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INSTRUMENTATION Automatic systems a r e a v a i l a b l e for d a t a h a n d l i n g , first step in process control

E WISH to comment on another Wstriking exhibit at the 25th Exposi-

tion of Chemical Industries held in Philadelphia, Dec. 5 to 9. The Honeywell automatic data-handling systems illustrate the situation which now exists in chemical process instrumentation. In many instances we are now at PNEUMATIC FLOW INPUTS

automatic data-handling systems. A reprint of his paper, presented at the Regional Meeting of the Western Petroleum Refiner's Association in Wichita, Kan., last June, has been useful in discussing details of this system. The general purpose and nature of this system are illustrated schematically

PNEUMATIC L E V E L a PRESSURE INPUTS

PRESSURE TO ELECTRIC TRANSDUCERS

FLOW INTEGRATORS TOTALIZERS A N D COMPENSATORS

SCALE FACTOR ADJUSTMENTS

PROGRAMMER

Figure 1. A u t o m a t i c data-handling system

the stage where we need instruments to read other instruments! In a complex process where important data are obtained at a prodigious rate it soon becomes impractical to record the data manually. The problem of data assimilation at high speed becomes mandatory in some of these processes and the costs are justified. The research scientist views these elegant devices with envy, because they could just as well serve his purpose in securing valuable fundamental data. Through the courtesy of Arthur H. Freilich, Minneapolis-Honeywell Regulator Co., Wayne and Windrim Aves., Philadelphia 44, Pa., we are able to present pertinent information on the VOLUME

2 8, N O . 3, M A R C H

Figure 2. 1956

by Ralph H. Mutter

in Figure 1. Information from a number of sources is translated into electrical signals by means of suitable transducers. Some of the information will be in the appropriate form to begin with, such as small d.c. potentials from thermocouples, or the potential from a pH measuring system. According to a preselected schedule, set up on the programmer, a set of selector switches will interrogate these signals sequentially and send them to a self-balancing linearizing potentiometer. The latter is similar to the conventional electronic recorder or controller, except that its output is in the form of a shaft rotation proportional to the quantity being measured. This output shaft drives an analog to digital converter, the output of which can operate any or all of four presentation devices : a bold visual display, a tape punch, an electric type-

Operator's desk 45A

instrument abstracts Applied

Physics

INSTRUMENTATION

Corporation/Pasadena/California

Extension of Spectrophotometer Range to 1860A Opens New Region for Analysis The extended ultraviolet wavelength r a n g e of the C a r y Model 14 Recording Spectrophotometer has opened a new region which will perm i t a n a l y s i s of a n u m b e r of c o m pounds not previously a d a p t a b l e to ultraviolet spectrophotometry with standard instruments. A c c u r a t e direct r e a d i n g absorbanee* to 1860A is now provided w i t h the Model 14 t h r o u g h the use of optical elements of increased ultraviolet efficiency in the double monochromat o r . T h e s p e c t r u m of m e t h y l e t h y l ketone vapor, s h o w n , i n d i c a t e s j u s t one class of compounds whose s p e c t r a in this region provide analytical possibilities. In addition to ketones, it is

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writer, or card punch. I n each case t h e d a t a appear as decimal digits. A digital clock controls the operations and prints the time a t the beginning of each logging cycle. Additional provisions in this system are means for scale factor adjustment, for high-low set points with alarm features, and a manual selector for selecting one of m a n y points b y hand. T h e latter has two forms: an adding machine keyboard or a telephone dial. Selection is achieved b y pressing keys or b y dialing a number. If averaged values are desired, rather t h a n the instantaneous value, an averaging circuit, in the form of an analog computer network, is used t o calculate t h e average value a n d feed this to the d a t a handling system. T h e average can be printed on each log cycle and the average for a 24hour period can be printed automatically a t t h e end of each day.

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2000A 1900A 2100A T h i s s p e c t r u m of m e t h y l e t h y l k e t o n e v a p o r illustrates t h e p e r f o r m a n c e of t h e Model 14 in t h e lower w a v e l e n g t h r e g i o n s .

T h e C a r y Model 14 S p e c t r o p h o t o m e t e r provides p e r f o r m a n c e t o 1860A, •with possibilities for even s h o r t e r w a v e l e n g t h s . H e r e t o f o r e such p e r f o r m a n c e w a s possible only on c u s t o m m a d e instruments.

IMPROVED VIBRATING R E E D ELECTROMETER F a s t e r , simpler m e a s u r e m e n t of radioactive isotopes, m a s s spectrometer ion c u r r e n t , small p H changes, etc these and other laboratory problems involving m e a s u r e m e n t of very small charges, currents, and voltages a r e now m a d e still simpler w i t h t h e new C a r y Model 31 V i b r a t i n g Reed E l e c t r o m e t e r t h a n by other methods. The new design provides ten o p e r a t i n g r a n g e s from 1 millivolt full scale to 30 volts full scale. Cary SPECTROPHOTOMETERS V I B R A T I N G REED AMPLIFIERS APPLIED PHYSICS C O R P O R A T I O N

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likely that" a l c o h o l s , mono-olefines, a r o m a t i c s and other compounds will also have useful s p e c t r a in this region. T h e p r i s m - g r a t i n g double mono c h r o m a t o r of t h e Model 14 is noted for its high resolving power with low scattered light (less t h a n a p a r t p e r million) in t h e ultraviolet, visible a n d n e a r i n f r a r e d regions. By u s i n g t h e new, more efficient optical elements in this double monochromator, t h e extended r a n g e is achieved. This development is the result of constant effort to improve the performance, reliability and usefulness of C a r y i n s t r u m e n t s b y t a k i n g full a d v a n t a g e of a d v a n c e m e n t s in m a t e rials, components a n d technology. F o r a d d i t i o n a l i n f o r m a t i o n on t h e n e w Model 14 and other C a r y ins t r u m e n t s , w r i t e for Bulletin ACS-10. *By use of readily interchangeable slidewires, the Model 14 will also record directly in transmittancc, log absorbance or other special functions.

T h e wider choice of r a n g e s m e a n s t h a t u s e r s can cover a wide r a n g e of i n p u t c u r r e n t s or voltages with t h e s t a n d a r d Model 31 a n d one or t w o input r e s i s t o r s , t h u s in m a n y cases e l i m i n a t i n g t h e need for special ins t r u m e n t m o d i f i c a t i o n s a n d accessories. T h e C a r y Model 31 replaces t h e f o r m e r Model 30 and provides all of the f e a t u r e s of t h e Model 30 plus t h e added a d v a n t a g e s of t h e new r a n g e s . A descriptive bulletin (No. ACE-10) a n d i n f o r m a t i o n on a p p l i c a t i o n t o specific p r o b l e m s a r e a v a i l a b l e .

instruments: ·

RAMAN SPECTROGRAPH INFRARED A N A L Y Z E R S

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ELECTROMETERS ULTRAVIOLET

3 6 2 WEST COLORADO STREET /

PASADENA

ANALYZERS I

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CALIFORNIA

For further information, circle numbers 46 A-1, 46 A-2 on Readers' Service Card, page 59 A

46 A

Figure 3.

Data-handling system

Figure 2 illustrates t h e operator's desk for an installation in current use on a process unit. E a c h of the two t y p e writers logs 68 variables. T h e variables include temperatures, pressures, levels, a n d flow rates. Flows are integrated hourly, totalized every day, and punched into tape for cost accounting. Some temperatures are averaged. T h e visual display and scanning board are also shown in this illustration. Figure 3 shows the Honeywell d a t a handling system, which was demonstrated a t the exposition. T h e various units reading from top to bo.ttom are the digital clock, self-balancing linearizing potentiometer, translator, t y p e writer a n d tape punch, a n d the twoprogrammer chassis. Figure 4 is the Honeywell scanner and alarm printer for checking process variANALYTICAL

CHEMISTRY

INSTRUMENTATION ables against individual high and low limits to signal the operator of process drift and give a digital trend record of abnormal conditions.

Figure 1.

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For further information, circle number 48 A on Readers' Service Card, page 59 A

48 A

Scanner and alarm printer

If one gains the impression, from what has been written here, that this data-handling system merely supervises a process, it would obscure the larger possibilities for the future. Indeed, the designers regard the system as an interim solution to the greater problems facing process control. We can do no better than quote Freilich verbatim: "Data handling is the first step in the direction of process control by real-time computers which will, at some future date, yield tremendous benefits in process efficiency. Before we can attain a closed loop control system with a computer performing vital calculation and decision-making functions, we must accumulate experience in digital techniques. This, then, is a subtle long range advantage of the automatic data handling system." Inorgan ic Microanalysis We have received the second volume of the "Traité de Micro-Analyse Minérale" by Clement Duval of Paris. This is the second of four volumes to appear on this subject. Volume II covers the elements Ti, V, Cr, Mn, Zr, Nb, Mo, Te, Hf, Ta, W, Re, Th, Pa, U, and the transuranic elements to Cf. The same excellent treatment and approach which characterized the initial volume are to be found here. Every possible technique of qualitative and quantitative analytical value is described for each element. These range from crystallographic identification and spot tests to such things as radio-frequency titrations, polarography, amperometric and potentiometric titrations, nuclear techniques, and mass spectrometry. We are compelled to repeat our expression of enthusiasm as before. This is a treatise for analysts who are interested in the whole subject of analysis. ANALYTICAL

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