I/EC A
INSTRUMENTATION
W O R K B O O K
F E A T U R E by Robert Wall, Plastics Division Monsanto Chemical Co.
Instrumentation Trends in 1957 1957 saw improvements in instrumentation paralleled by the development of better techniques of use
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OVER-ALL IMPRESSION of q u a l i t y
improvement is derived from a general review of 1957 progress in instrumentation—in areas of both manufacture a n d use. This p r o b ably reflects the effects of tightening competitive pressures. Instrumentation appears to have been generally improved in all aspects of quality, including accuracy, speed, versatility, m a i n t e n a n c e requirements, a n d appearance. I n s t r u m e n t users are applying more instrumentation more carefully to obtain m a x i m u m production efficiency from their processes. Process Gas Chromatograph Analyzer T h e major instrumentation development of the year is probably the commercial availability of process gas c h r o m a t o g r a p h analyzers. This remarkably simple a n d competent analyzer makes possible a significant extension of analytical process control. T h e r e was only limited use of commercial gas chromatographs in 1957; however, this instrument has been proved, substantially, by the extensive applications of h o m e m a d e gas c h r o m a t o g r a p h units. T h e laboratory gas c h r o m a t o g r a p h analyzer a p p e a r e d in 1955, yet it has required about 3 years for the process gas c h r o m a t o g r a p h to become commercially available. This time interval is indicative of a growing awareness by the manufacturers of process analysis instrumentation of the m u c h more severe performance requirements placed on the process analyzer as compared to the corresponding laboratory instrument. Very complete development plus inplant tests of prototypes by cooperating users are now customary before
a new analyzer is placed on the market. These new gas chromatographs, in general, a p p e a r to be well-developed process analysis instruments. An appreciable growth in the interest in a n d use of process analysis instrumentation was a p p a r e n t in 1957. This parallels the improved availability of reliable a n d competent versatile analysis equipment, a n d the development of a background of applications experience that has m a d e process analysis installations almost routinely successful. T h e sample system is confirmed as the key essential for a successful installation. Detailed attention to requirements, a conservative design, careful construction, a n d systematic maintenance procedures are essential for success in process analyses. User experience proved that the pay-out of direct analytical process control m a y be very large. Better control effecting a 1 % increase in productivity with the same r a w material input a n d processing cost equals a very large dollar return for the large processing plants. I t is interesting, a n d often profitable, to survey a plant for incremental savings that are possible from increased yields a n d / o r reduced losses, a n d to examine critically the control system for the possibilities of realization of these potential savings. M o r e people did this in 1957, a n d savings of several h u n d r e d thousands of dollars per year were not u n c o m m o n . Data Reduction Equipment T h e use of d a t a reduction equipment seems to be developing into a definite trend—particularly for the more complex process plants. Definite improvements have been m a d e
in factors determining reliability and m a i n t e n a n c e requirements, a n d use of d a t a reduction has increased accordingly. Tidewater Oil's Delaw a r e refinery probably presents the largest application of d a t a reduction presently in use a n d appears to be completely successful. D a t a reduction is proving to be a substantial solution to the problems of rapid assembly of control information for large a n d complex processes in an organized presentation. I t is also well adapted to further progress in control techniques. C o m p u t e r equipment has advanced considerably in adaptability for process control use, a n d in those factors affecting reliability and maintenance that have been a major objection by the potential users. W e n o w have computer equipment capable of integration with d a t a reduction to provide systems capable of fully automatic process control. Certainly m u c h further progress m a y be expected in the development a n d refinement of this equipment, but the major point is that practical, usable equipment is now available. T h e r e have been very few applications of computer control, a n d these have been very limited in scope. A background of knowledge of process dynamics is necessary before the full potential of t r u e o p t i m u m plant operation efficiency by completely automatic computer control can be realized. This is a very difficult area of work in which only the user is in a position to study it fully. Most of t h e major companies have groups active in the study of process dynamics—in some cases, in cooperation with the computer manufacturers. Steady progress is being m a d e in building a background of basic knowledge, a n d the -large laboratory computer has VOL. 50, NO. 1
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JANUARY 1958
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I/EC Today's Modern Industry Demands a Modern Thermometer
PALMER RED-READING MERCURY THERMOMETERS
Red-Reading Mercury
Extruded Brass Case
Chrome Finish
Ranges - 4 0 to 950°F or
INSTRUMENTATION
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been the key tool in these studies of the dynamic behavior of processes. At present, the instrumentation has advanced beyond the techniques of application; we have the instrumentation but no one knows quite what to do with it. Electronic Instrumentation Progress Electronic instrumentation m a d e major progress toward transistorized and magnetic amplifier circuitry during 1957. M a n y instruments are now completely transistorized. This is largely a natural consequence of the improved availability a n d reduced cost of an adequate line of transistors. T h e vacuum tube is not out; it will continue to be used where its characteristic properties are advantageous. T h e use of plugin circuit cards is the rule—a technique derived from the methods used in data reduction and computer construction, which facilitates replacement troubleshooting with subsequent shop repair of the defective unit. Experience will prove how well the circuit cards are adapted to use in process plant instruments. T h e quality of construction appears uniformly high, a n d it is obvious that particular attention was given items of particular concern regarding maintenance.
Equivalent in C
Write for Complete Information Ask for Bulletin No. 35
PALMER THERMOMETERS, INC. Mfrs. of Industrial Laboratory, Recording and Dial Thermometers
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A Workbook Feature tenance manpower required, plus the, perhaps, more important benefit of reduced down time. Replacement troubleshooting by plug-in units returns a faulty instrument to service more quickly a n d enables the more efficient shop repair of the defective unit. Efforts to reduce m a n p o w e r requirements have two objectives: to reduce the m a n hours required, and to simplify the maintenance procedures so that less skilled m e n can be used. I m p o r t a n t progress was m a d e in 1957 through improved convenience and reliability factors, and through construction, which enables more extensive use of replacement repair. This helps but does not solve the problem of manning the modern instrument d e p a r t m e n t to handle the rapid advances in process control instrumentation. T h e Tidewater refinery experiment in contract instrument maintenance is one answer to the problem of obtaining skilled instrumentation personnel. T h e participants report that the system has been satisfactory thus far. Regardless of how successful contract maintenance is, the acceptance by the chemical a n d petrochemical industries will be m u c h slower t h a n that in the less secretive refinery area. Outlook
Installation and Maintenance Problems Emphasis on maintenance, or more broadly on m a n p o w e r requirements, is evident throughout all of the progress in instrumentation. T h e r e is an awareness and recognition of the difficulty of obtaining the quality and quantity of men required to handle competently instrumentation that is growing rapidly in both complexity and quantity. T h e instrument manufacturers are making every effort to minimize the manpower requirements of instrumentation. Cabled air lines enable a n appreciable saving in installation costs and a further saving in minimizing maintenance resulting from corrosion or other forms of damage. T h e convenience of quick couplings reduces installation and replacement time. Prefabricated assemblies significantly reduce installation time. Built in reliability reduces the main-
INDUSTRIAL AND ENGINEERING CHEMISTRY
Progress in instrumentation through 1958 m a y be expected to follow the pattern of 1957—a steady improvement in quality, reliability, and performance. T h e manpower problem will remain, with further progress in reducing both the maintenance and skill required. M o r e use of d a t a reduction, some extension in the use of computers in direct process control, and probably a greater variety of electronic process controllers seem indicated. W h a t ever the direction, the dynamic growth of instrumentation that was evident through 1957 will continue.
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