INSTRUMENTATION

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INSTRUMENTATION A new general-purpose commercial instrument represents a very close approximation to a universal laboratory recorder

Λ / Γ Α Ν Υ of the instruments used by the -L'A analyst include a recorder, not as an attachment, but as an integral part of the total instrument design. To the extent that automatic recording fur­ nishes continuous and detailed informa­ tion about a phenomenon, this practice ma3' be expected to increase. Fortu­ nately, the modern investigator has a great range and variety of recorders at his disposal. For a long time, com­ mercial recorders were designed and produced for a few limited tasks; for temperature, pressure, flow rate, and a few other simple variables. At present, they are employed in the measurement, recording, and controlling of almost every known phenomenon. They are rugged and reliable enough to be used in aircraft and other vehicles. They can be modified in range, speed, and ability to accept input signals of almost any kind. It may be that their extreme versatility makes it impractical to supply any one instrument suited to a wide variety of applications, yet this is precisely what is needed in the research

laboratory. Every manufacturer is pre­ pared to modify a standard recorder of his line to suit the precise needs of the customer. As one of those analysts who regard a recorder as second in importance only to the analytical balance, we are highly interested in the new Fisher Recordall, which is indeed a very close approxima­ tion to what Fisher designates as a "universal laboratory recorder." This general-purpose laboratory recorder with a wide range of useful accessories is manufactured by the Fisher Scientific Co., 717 Forbes St., Pittsburgh 19, Pa. Complete details are available in Bulle­ tin FS-251. A general view of the Recordall is given in Figure 4. The cabinet is easily rolled wherever needed and recorder and control panel are just above the

by Ralph H. Müller

average laboratory bench top. Lower portion of the cabinet provides complete space for storage of charts, ink, and accessories. The control panel is shown in Figure 5, where the various function and range settings are applied. For resistance measurements, there are six ranges from 11 to 5500 ohms full scale; 11 d.c. potential ranges from 5.5 mv. to

Figure 2

MELTING AND FREEZING CURVE OF A TIM ALLOY, HADE WITH THE FISHER RESISTANCE THERMOMETER BULB AND PLOTTED ON THE FISHER RECORDALL

Figure 1 VOLUME

2 7, N O .

11, N O V E M B E R

Figure 3 19S5

49 A

INSTRUMENTATION

From analytical research to process stream analysis...

550 volts full scale; 11 current ranges from 5.5 μ&. t o 550 m a . full scale. T h e operator has a choice of 11 chart speeds t h r o u g h a gear-changing com­ bination. These range from 3.75 u p t o 60 inches per hour. P e n speed is 3 seconds for full scale (11 inches) or approximately 4 inches per second.

Cary Instruments provide greater versatility, accuracy, reliability RECORDING SPECTROPHOTOMETERS

Cary Spectrophotometers are designed for the rapid recording of spectra with good resolving power and high photo­ metric accuracy. In several years of field experience, these instruments have shown the ruggedness and relia­ bility needed for routine laboratory service . . . plus the flexibility to han­ dle a variety of problems in the re­ search laboratory. RAMAN

SPECTROPHOTOMETER

The Cary R a m a n Spectrophotometer uses a unique optical system which offers at least 10 times the light gather­ ing power of previous designs. This and other features provide an instru­ ment that takes full advantage of r a m a n spectroscopy "with high speed and accuracy. ELECTROMETERS

Cary "Vibrating Reed Electrometers... for measuring very small currents (as little as 10—17 amperes), charges and voltages . . . provide high sensitivity and accuracy with good stability and reliability. Several models are avail­ able for a variety of applications . . . carbon 14 determination, mass spec­ trometry, pH determinations and many similar applications.

Versatility is accomplished through a wider choice of operating ranges, re­ sponse speeds, sizes and types of sam­ ples, sensitivity, a variety of standard and special accessories and custom adaptations for special problems. Accuracy is achieved by the use of ad­ vanced design principles which insure the maximum performance permitted by the present state of the art . . . de­ velopments which make available sen­ sitivity, stability and reproducibility unattainable with other standard in­ struments. Reliability is built into Cary Instru­ ments, for example, by using sapphire and carboloy at points of critical wear . . . by employing kinematic principles wherever positions or motions must be precise and reproducible . . . by design­ ing circuits so even large changes in characteristics of vacuum tubes and other components will not affect in­ strument performance. For more comprehensive descrip­ tions including sample curves, of the complete line of Cary Instruments, •write for Bulletin AC-8.

Figure 4

Figure 5

INFRARED A N A L Y Z E R S

Cary Infrared Analyzers, for continu­ ous analysis of flowing samples, util­ ize selective detection and a double beam optical system. They are more free from zero drift and have higher inherent discrimination against inter­ fering sample components than other similar types of analyzers. This pro­ vides unusual adaptability to difficult analytical problems requiring high sen­ sitivity and accuracy in complex mix­ tures. ULTRAVIOLET ANALYZERS

Cary Ultraviolet Analyzers provide a simple, reliable means of continuously analyzing flowing samples for compo­ nents which absorb UV or visible ra­ diation or which can be converted to a suitable absorbing substance.

APPLIED PHYSICS CORPORATION 362 W. Colorado Street, Pasadena 1, California

INSTRUMENTS

M o s t useful is t h e Fisher provision for directly applicable accessories for this recorder. A m o n g these are : A resistance thermometer bulb to plot temperature directly from —100° to 320° C. An adapter for the Beckman Model H-2 p H meter, which enables the Recordall to record p H continuously from p H 0 to 11 when used in connection with the Recordall zero shifter. Zero shifter permitting the shifting of electrical zero to any point on the scale. Control accessory, consisting of switch attachment to recorder for the purpose of automatic control. Single- or two-point attachment. Vacuum adapter. Direct reading from 1 to 1000 microns. Pressure adapter. Direct reading in pressure in three ranges: 0 to 100, 0 to 500 pounds per square inch, and com­ pound vacuum-pressure range for 0 to 30 inches of mercury (vacuum) and 0 to 50 pounds per square inch (pressure). Elecdropode adapter kit. A drive for the potential dial of the polarographic system of Fisher converting this instru­ ment into an automatically recording

For further Information, circle numbers 50 A-1, 50 A-2, 50 A-3, 50 A-4, 50 A-5 on Readers' Service Card, page 55 A

50 A

ANALYTICAL

CHEMISTRY

INSTRUMENTATION

Model E-6-15A Nobatron . . . WHEN

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accurate · dependable · economical

For more t h a n t e n y e a r s , Sorensen NOBATRONS h a v e p r o v i d e d r e g u l a t e d , l o w - v o l t a g e , h i g h current DC in t h o u s a n d s o f l a b o r a t o r y a n d i n d u s t r i a l a p p l i c a t i o n s . Their users h a v e chosen t h e m f o r their ± 0 . 2 % r e g u l a t i o n accuracy, t h e i r convenience o f use c o m p a r e d w i t h b a t t e r y i n s t a l l a ­ tions or other sources, t h e i r d e p e n d a b i l i t y , their easy m a i n t e n a n c e . N o b a t r o n circuits usually e m p l o y o n l y three t u b e s . They a r e easily accessible f o r replacement w h e n r e q u i r e d . The characteristics listed b e l o w a r e c o n s e r v a t i v e a n d t e l l y o u w h y y o u s h o u l d specify N o b a t r o n . Models available (numbers indicate voltage & current) E-6-5A, E-6-15A, E-6-40A, E-6-100A, E-12-15, E-12-50, E-28-5, Ε-28-10, E-28-30, E-28-70, E-28-150, E-48-1S, E-l25-10, E-200-S.

E-12-5,

ELECTRICAL CHARACTERISTICS Input 95-130 VAC, 10, 50-60 cycles. 120/208, 3 0 , 4-wire w y e for the E-28-150. The E-28-70 requires 190/260, 10 power. Reg. accuracy ± 0 . 2 % against line, ± 0 . 2 % against load. Ripple Varies to 1 % RMS max. under worst conditions. Load range 1/10 to f u l l toad. Output range Adjustable ± 1 0 % ; down to 2 0 % at lesser accuracy. Recovery time 0.2 seconds on all models up to 1 KW rating, increasing to 0.5 seconds at 10 KW. Note: " A " models output either 6 or 7 volts. •Reg. U.S. Pat. Off. NOBATRON-RANGERS Your interests m a y best be served by an i n s t r u m e n t w i t h electrical characteristics s i m i l a r t o the s t a n d a r d N o b a t r o n , b u t w i t h stepless, continuously a d j u s t a b l e o u t p u t . I f so — f i n d out more a b o u t Sorensen's line o f Nobatron-RANGERS. ELECTRICAL CHARACTERISTICS Input 95-130 VAC, 1 0 , 50-60 cycles for SR30 and SR100. 190-260 VAC, 10, 50-60 cycles for the SR2. Reg. accuracy ± 0 . 2 5 % at any voltage setting. Ripple 1 % RMS max. Output: Model SR100 SR30 SR2 VDC 5-135 5-30 100-300 Amps 1-10 3-30 1-10 TUBELESS N O B A T R O N S Sorensen is a w a r e o f the a d v a n t a g e s o f tubeless circuitry, a n d m a n u f a c t u r e s a line o f tubeless supplies, a l s o . M o d e l SR2 ELECTRICAL CHARACTERISTICS ~" Model MA65 MA640 MA2850 I n p u t , VAC, 60-v 105-125,10 105-125,10 190-230,30,4-wire, wye O u t p u t , VDC 6, a d j . ± 1 0 % 4.5-7.7 a d j . 23-32 a d j . Load range 0-5 amp. 0-40 amp. 0-50 amp. Ripple 1 % max. 1 % max. 3 % max. Model Reg. accuracy b l . 0 % for any combination of line and load. MA640 Recovery time 0.2 sec. 0.15 sec. 0.5 sec. Catalogs available describing the complete line of Sorensen instruments. Write for free copies today.

SORENSEN & CO., INC., 375 FAIRFIELD A V E N U E , STAMFORD, CONNECTICUT For further information, circle number 52 A on Readers' Service Carl, page 55 A

52 A

system (Figure 2). A typical polarogram taken with this attachment is shown in Figure 1. Standard thermocouples can be used with the Recordall. In the case of Chromel-Alumel thermocouples for the range 0° to 1000° C , cold junction compensation is provided within the instrument and special chart paper is available graduated directly for this temperature range. An example of thermometric measure­ ments is shown in Figure 3 for the melting and freezing of a tin alloy. These results were obtained with the resistance thermometer bulb. Other primary elements and trans­ ducers are being developed and will be described as they become available. Of particular interest would be im­ pedance matching circuits for use with vacuum phototubes. Fisher reports that such developments are well under way. The existing adaptation to the glass electrode pH meter indicates that comparable cases can be handled. The flexibility and wide utility of this equipment should be very interesting to the research-minded analyst. Re­ corders are not scarce in analytical laboratories, but as a rule, they have been incorporated in specific-purpose instruments. Compilations A few years ago, Du Mont issued a pamphlet on transducers or primary elements, primarily those which are suitable for presenting physical infor­ mation to an oscilloscope. This was an extremely useful compilation for the research man. It listed characteristics, range, and limitations, and also de­ scribed sources of such equipment. The advantages of this compilation were described in this column at the time. A similar compilation for recording potentiometers would be most useful. We are aware that this sort of thing has been done from time to time by our good friends who build recorders, and indeed, as stated above, they are pre­ pared to make valuable suggestions as our problems arise. It is also true that dozens of transducers for specific prob­ lems are on the shelf awaiting applica­ tion. Nevertheless, this is a resume which is appropriate at frequent inter­ vals and it does no particular harm to repeat, and to bring up to date, a listing of those devices. We are one of those investigators who manage to keep many recorders on hand, of wide range and versatility, but despite this, a new problem or new approach finds us busy with the very first consideration—a transducer element to convert the phenomenon into something which we can "hook on" to the best recorder. ANALYTICAL

CHEMISTRY