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a
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Instrumentation
Automation 1961 Trends and Instrumentation at the 1961 Instrument Society of America Automation conference and show by P. H. Stirling and Henry Ho, Canadian Industries, Itd.
N i n e t e e n sixty one has been yet another year of quiet consolidation with few new techniques of wide potentiality appearing on the scene. T o the process engineer who is more interested in reliability, convenience, and economy the second and third generation instruments now making their appearance are more encouraging than any new instrument based on some recently developed principle which has been hurriedly moved from the laboratory into field guise. Theme of the 1961 ISA conference was reliable information and many of the papers dealt with advanced Calibration techniques and testing methods. Growing awareness of the importance of strain-gage instrumentation was shown by over 15 papers devoted to this field with a third of these making a strong plea for standardization of terminology and practices, always the sign of a maturing field. A third of the 15 papers on temperature measurement was also devoted to standardization and calibration techniques. Perhaps the most significant paper in this group was the lengthy report on the development of the tungsten-tungsten rhenium thermocouple into reliable thermocouple wires capable of meeting calibrations up to 4200’ F. within 1% or better (Hoskins Co.). Use of tungsten 5% rhenium-tungsten 20yo rhenium thermocouples was also shown to result in an improved thermocouple which does not embrittle, as does tungsten, and is more suitable for use in the 0’ to 3000’ F. range than the tungsten combination. Differing reliability, demands of large process ind.ustries, and small instrumentation users were the subject of several papers and much discussion. The trend toward the systems concept requiring over-all reliability, much environmental control, and self-checking techniques
that were appealing to the large process user was felt to be unattractive to the smaller user who demands minimum maintenance but who can accept system failure. Overload, neglect, and severe environmental conditions are more likely to be met in the small user area. Instrumentation must take account of this. Widespread realization by manufacturers that the instrumentation market is not homogeneous and that reliability concepts must reflect user usage augurs well for a healthy instrument industry. On-line computers are still a subject of hot debate but the trend toward special purpose digital computers is now well defined and the small general purpose unit is now correctly considered as only a portion of the package. Electronic Associates, Inc. created great interest with their well designed special packaging of an expandable general purpose “patch board type” electronic analog computer for process control (Type PC-12) further advancing the concept first marketed by Southwestern Industrial Electronics of on-line electronic analog computation. In the area of on-line computing, the process of consolidation is proceeding rapidly and more realistic marketing is to be expected in the future as the drastic competition sorts out the field. N e w Instrumentation
Pneumatic Analog Computing Elements. AiResearch’s neat modules for pneumatic analog computing attracted the widest attention of any new product a t the show. There are many competitive pneumatic analog computing devices, but this comprehensive line represents a considerable advance in the art because
of the thoroughness of their building block approach, wide interchangeability of component parts, and excellent precision. These will undoubtedly form the basis of many small on-line computing loops and offer both the small and large user the possibility of developing advanced controls for units a t reasonable prices. h4oore Instruments also offer a n advanced control concept in a simple pneumatic form. Their new optimizing control unit which operates on a continuous sweeping principle is a challenge to instrument engineers to apply modern theoretical concepts in their own bailiwick. At present optimizing unit operation costs has seemed a pipe dream to many but with this device plus some ingenuity there are a host of possibilities that could turn into interesting savings. On-Line Refractometers. Two new refractometers were shown, one by Waters Associates and the other by Daystrom Inc. The latter is available in sizes up to 8-inch pipe, covers a range of 1.3 to 1.65 refractive index units, and can operate over a pressure range from vacuum to 150 p.s.i. I t is extremely rapid in response (about 4 milliseconds). Both this and the Waters Associate’s refractometer eliminate the need for a troublesome sampling system and are true on-line instruments. The latter, which is more sensitive, uses a critical angle reflection technique and has an adjustable span of 0.005 to 0.10 refractive index unit which may set anywhere in the usual range. As usual, higher precision requires a compensating design compromise and this unit is somewhat slower (time constant about 10 seconds). Because it does not view across a stream it can be used in many situaVOL. 53, NO. 12
DECEMBER 1961
65A
INSTRUMENTATION tions where conventional refractom-" eters would be useless (air bubbles, opacity, etc., do not affect this instrument). Strain Gage Devices. Semiconductor strain gages capable of five volts output for 1000 microinches of strain were reported by KuliteBytrex as a ultrahigh level output device. This is a far cry from the millivolt normally associated with such a level of strain. Micro Systems, Inc., showed an interesting displacement transducer based on four semiconductor gages. This using an ingenious cantilever system allowed a 2-inch displacement and gave 2 volts output. The device is temperature compensated giving only 1% shift for 100" F. change. A high output pressure transducer for the medium pressure range using semiconductor gages was also shown by this firm together with new construction for their wellknown coaxially cased "etched wire" weld-on gages. Another semiconductor strain gage pressure transducer was offered by Fairchild Controls and is available in a wide variety of ranges from 0 to 10 and 0 to 10,000 p.s.i. with outputs in the 0 to 50 or 0 to 250 mv. range. For telemetering purposes a small
solid state amplifier may be added at the transducer to increase the output from 0 to 5 volts. This device is usable over the -65" to +250" F. range. Semiconductor Temperature Elements. Although thermistor techniques have been steadily advancing until now it is possible to obtain replacement resistance elements with reproducible and constant characteristics (Fenwal Co.), new types of semiconductor temperature elements are now appearing. Silicon semiconductor elements which allow outputs of up to 10 mv. per "F. and which can be chosen so as to be linear over a 400" F. range were described by Micro Systems Inc. These have a positive temperature coefficient in contrast to the thermistor and are becoming available in similar small bead (1/16-inch diameter) configurations. Time constants in the 20 to 50 millisecond region are reported for one configuration. High output, small size, and fair linearity make this device extremely attractive. We can safely predict that some of these will rapidly find their way into process usage. Electric Valve Actuators. Lear, Inc., Electromechanical have solved one of the knottiest design problems
SUPPLIERS AiResearch, Garret Corp., Pheonix, Ariz. American Systems, Inc., Schlumberger Well Surveying Corp., 16253, 126 Street, Hawthorne, Calif.
International Business Machines Corp., 590 Madison Avenue, New York 22, N. Y. Kulite-Bytrex Corp., Newton 58, Mass.
50
Hunt
Street,
Barber-Colman Co., Wheelco Industrial Insts. Div., 1300 Rock Street, Rockford, Ill.
Lear, Inc., 110 Ionia Ave., N. W., Grand Rapids 2, Mich.
Beckman Insts. Inc., 2500 Harbor Blvd., Fullerton, Calif.
Micro Systems Inc., 319 Agostino Road, San Gabriel, Calif.
Bristol Co., Data-Master Corp., Helicoid Gage Div., Waterbury 20, Conn.
Minneapolis-Honeywell Minneapolis, Minn.
Daystrom, Inc., Weston Instruments Div., 614 Frelinghuysen Ave., Newark 12, N. J.
Moore Instrument Co. Ltd., 169 McCormack Street, Toronto 9, Ontario, Canada
Electronic Associates, Inc., Long Beach Avenue, Long Beach, N. J.
Nanmac Corp., 55 Glymont Road, Indian Head, Md.
Fairchild Controls Corp., 225 Park Ave., Hicksville, L. I., N. Y.
Perkin-Elmer Corp., Main Avenur, Norwalk, Conn.
Fenwal Electronics, Ashland, Mass.
Inc., 111 Pleasant,
Rosemount Engineering Co., 9424 Lyndale Ave., S., Minneapolis 20, Minn.
General Electric Co., Instrument Department, 40 Federal Street, West Lynn, Mass.
Southwestern Industrial Electronics, 2831 Post Oak Road, Houston, Tex.
Hoskins Manufacturing Go., 4445 Lawton Ave., Detroit, Mich.
Regulator
Co.,
Waters Associates, 45 Franklin Street. Framingham, Mass.
of the decade. They have come up with a n all electric valve actuator capable of a 1000-pound thrust, rapid response, and which is compact and smooth working. They use a continuously rotating motor and a dual coil, dry magnetic powder clutch system. Control coils accept all common direct current signals (1-5, 4-20, 10-50 ma.). The actuator can travel close to 1 inch a second a t full thrust and has a 2.75-inch stroke. It has a band width of 3 cycles per second and follows one cycle a second accurately. It has a linearity of of full stroke. This is another vital step forward in the perfection of all electric control system and it is to be expected that the demand for this type of actuator will increase rapidly with the increasing trend toward electronic controls. Power Controllers. Silicon-controlled rectifiers are now moving into larger industrial sizes and are making a fair bid to displace saturable reactors. Barber-Colman now offer a 30 KVA 60 cycle per second unit with full wave output capable of being controlled by 0 to 5 or 0 to 10 ma. direct current in their 620 series. These devices again offer many advantages to the all electric control system designer. Triple Bridge TemperatureMeasuring System. Rosemount Enqineering has developed a n ingenious extension of the Kelvin double bridge principle which enables them to obtain very high accuracies with commercial three-lead resistance thermometers. This virtually eliminates all lead errors. In their model 551B a 12-module triple bridge system is mounted in a standard rack size. This instrument together with the new resistance elements represents a significant step forward in attaining the higher precisions in industrial temperature measurement demanded by computer control. Conventional lead errors can be cut by factors in the 50- to 100-fold region using this system. High Speed Thermocouples. Process investigation teams and equipment designers will do well to become acqu.*inted with the ablative thermocouple designs by the Nanmac Corp. Some of their designs are reported capable of achieving speeds of response in the tens of
(Continued on page 68A )
66 A
INDUSTRIAL AND ENGINEERING CHEMISTRY
COATING FORMULATORS: How Shell’s new PENTOXONE*and PENToXOL* solvents can save money, improve formulations and eliminate the need for specialty high boilers HELL’S
S
PENTOXONEand PENT-
oXOL are unusually active high
boiling solvents. Together, they constitute a virtually complete high boiler inventory. Relow is solubility data for 30 important resins in PENToXONE and PENToXOL sdvents. With ncrylics, tzitrocellulose and alkyds, these new Shell solvents can
improve your formulations. With vinyls, PENToXONE lowers solvent cost and improves odor. W i t h t h e r m o s e t t i n g acrylics, epoxies and cellulose acetate butyrate, both PEKToXONE and PENToXOL give excellent film properties. I n urethaize systems, PENToXOn’E solvent has low isocyanate reactivity, eliminates need for premium priced upgraded solvents.
I n p o 1yv i n y 1 b u t y Y a 1 1ac q ue r s, PENToXOL can lower solvent cost by 11$ per gallon and almost double water resistance. If you’d like to receive samples, plus technical bulletins on all of these applications, write any of Shell’s nine Industrial Chemical Division Offices, or directly to Shell Chemical Company, 110 West 51 Street, Kew York 20, N. Y.
Solubility of resins’ in Shell’s PENToXONE and PENToXOL solvents. PENToXOLa PENToXONE
Solvent Resin
N itrocel Iu lose R.S. 1/2-Second G.ade, Eight Grams per 100 MIS S.S. %.Second Grade, Eight Grams per 100 MIS Acryloid A-21, 1 5 % Weight Acryloid 6-44, 1 5 % Weight Acryloid 6-66, 15% Weight Acryloid AT-50, 30% Weight Bakelite BKS-2600 Amberol F-7 Methylon 7 5 1 0 8 Beetle 227-8 Uforrnite F-240 Beckamine P - 1 9 6 Cymei 248-8 MM-55 Resimene 872 Cellolyn 102 Amberol 801 Aroplaz 2480 Rezyl 412 Cellolyn 552 Cellolyn 582 Duraplex ND 7 7 8 Aroplaz 6006 Cycopol 102 Half-Second Butyrate 10% Weight Vinylite XYHL, 5% Weight Parlon P Buton 200 Epons 1002, 50% Weight EponB 1007
Supplier
Rohm & Haas Co. Rohm & Haas Co. Rohm & Haas Co. Rohm & Haas Co. Union Carbide Plastics Co. R o h m & Haas Co. General Electric Co. American Cyanamid Co. Hercules Powder Co. Reichhold Chemicals Inc. American Cyanamid Co. Monsanto Chemical Co. Monsanto Chemical Co. Hercules Powder Co. Rohm & Haas Co. Archer-Daniels-Midland Co. American Cyanamid Co. Hercules Powder Co. Hercules Powder Co. Rohm & Haas Co. Archer-Daniels-Midland Co. American Cyanamid Co. Eastman Chem. Products, Inc. Union Carbide Plastics Co. Hercules Powder Co. Enjay Chemical Co. Shell Chemical Co. Shell Chemical Co.
Solvent
Viscosity, Cps., 2 5 ° C
100
67
58
38
30 25
22 20 15 63 46 19 5 26
25 90 87 37
11 31 11 14 19 23 29 18 32 27 13 25 17 42 27 80 117 55 1260 45 898 229
7 8 11 14 16 9 17 24 14 19 12 31 23 62 75
Remarkable activity of Shell’s PENTOXOXE high boiling solvent comes from this unique keto-ether structure. The COC of ethers and the double bond 0 of ketones combine for double action solvency. Shell’s P E N T ~ X O Lsolvent is a very closely related glycol ether. Both these solvents are true high boilers. PENTOXONE’S total evaporation t i m e i s 2 4 5 0 seconds. PENTOXOL’S is 3 3 7 5 seconds. *Shell Trade AIark.
630 31 240 107
( 1) Commercially available resin reduced to 30 per cent weight solids, except as indicated. Viscosities of resulting solutions measured in absolute units with capillary tube viscometers.
Shell Chemical Company I n d u s t r i a l Chefnicals D i v i s i o n
Circle NO. 43 on Readers’ Service Card
VOL. 53, NO. 12
o
DECEMBER 1961
67A
INSTRUMENTATION
CONTINUOUS EXCHANGER ~
~
MAKES ION-EXCHANGE FEASIBLE A S A U N I T PROCESS IN MANY NEW CHEMICAL APPLlCATl ONS Ion-exchange equipment of the conventional “fixed-bed” type is not always suitable for the more complex chemical-separation or recovery-concentration applications. Resin capacities in terms of product volume are often relatively low, and product analysis will vary throughout the cycle, since the operation is started with a freshly regenerated bed of resin and run until the bed is largely exhausted. I n the ILLCO-WAY Continuous
Counter-Current IonXchanger, o n the other hand, an adequate depth of freshly regeizerated resin is alwnys presented t o the product stream; high regeneration efficiency and low product dilution are achieved. Total volume of resin required is often a fraction of the amount needed in fixed-bed exchangers. As a result of these advantages, separations and recoveries which are not feasible with conventional equipment can be handled by the Contimuous IonXchanger.
CONTINUOUS ION-EXCHANGERS ARE SUCCESSFULLY OPERATING NOW If you have an application which can be accomplished in the laboratory, IWTengineers can design and build practical equipment of any size. for detailed information, address:
Circle No. 21 on Readers’ Service Card
68 A
microseconds region. They offer custom designs which are designed to have minimum interference with the natural heat flux in the vessel wall in a wide variety of shrouding materials and thermocouple materials. Trace Analysis of Vapors b y Coulometry. American Systems, Inc., offers a n extensive range of coulometric analyzers (Olfactron) capable of measurements in the parts per million range. Their Model 4070 is capable of detecting 0.2 p.p.m. of hydrazine or dimethylhydrazine in air and is available with 0 to 10 and 10 to 50 p.p.m. ranges. Model 401 0 is capable of monitoring the major sulfur components in natural gases. Digital Process Control Computer. I.B.M. offer a new three major component computing system for process control. This is based upon their versatile 1620 computer and uses the 1711 Data Converter and the 1712 Multiplexer. This particular combination is noteworthy for the low cost of the minimum package available and the extremely flexible multiplexer unit. Integrated Process Chromatography Digital Control System. The TADS (total analysisdigital system) for large process chromatograph systems by the Perkin-Elmer Co. aroused great interest. This system uses disk-shaped punch cards for storage of control command routines and processes the’ analog signals from the chromatograph into normalized concentrations which are then printed out on a n I B.M. typewriter. It is czpable of handling up to 40 components per analysis. This extremely flexible system supplies the control system designer with a n integral package well suited to incorporation into any datalogging or computer control system. p H Meters and Electrodes. The new Beckman Model J p H meter and the new line of industrial pH electrodes displayed at the show are the combination of over a decade of development to meet process requirements. Advantages of low impedance, rugged construction, and small size of the new glass electrodes were immediately appreciated by the majority of instrument engineers. Internal resistances of 10 to 20
INDUSTRIAL AND ENGINEERING CHEMISTRY
megohms at 25’ C. will enable these electrodes to function successfully in severe environmental conditions and broaden the range of possible measurements considerably. T h e selfpressurizing reference electrode usable u p to 15 p.s.i.g. and the simple pressurizing chamber system for usage u p to 100 p.s.i.g. enables these electrodes to be inserted directly into many process lines, thus eliminating lags due to sampling systems. The Model J p H amplifier is a robust solid state unit using a chopper modulator for direct current amplification. In the universal version it has both millivolt and milliampere outputs so that it can be used with practically any conventional recorder. Scale expansion (2 p H full scale) is available and thermo-compensation is unaffected by this, making the unit particularly suitable for installations requiring extreme closed loop control. Alarm features are also available on this unit. The unit is best described as a good example of a third generation instrument specifically tailored to suit process needs and will be favorably received by many. Boron Analyzer. An on-stream neutron absorptiometer (General Electric Co.) was described which has been applied to measuring boron concentration in plant streams. Analyses in the range of 0 to 2.0 grams per liter can be handled with a response time of 5 seconds, and it can handle flows up to 150 g.p.m. and down to 1 g.p.m. Small Pneumatic Indicators. Both Bristol (670 series) and Honeywell (Teloset) now offer a line of small pneumatic indicators and controllers in which the old nuisance of pressure balance has been overcome. I t is no longer necessary in these instruments to pressure-balance when switching from manual to automatic. This simple advance will eliminate a vast amount of operator irritation and is exceedingly welcome.
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Our authors like to hear from readers. If you have questions or comments, or both, send them via The Editor, I/EC, 1155 16th Street N.W., Washington 6, D. C. letters will be forwarded and answered promptly. *
