NEW PRODUCTS Equipment
LOW ENERGY ELECTRON DIFFRACTION SYSTEM Recent& available L E E D system Provides capability f o r examination of the microfeatures of solid surfaces and surface phenomena of increasing importance T h e advent of commercially available low-energy electron diffraction (LEED) equipment provides new opportunity for industrial study of the microscopic features of solid surfaces. With the announcement by Varian Associates, Inc., of their LEED system comes impetus for new examination of surface phenomena of importance, such as epitaxial crystal growth, heterogeneous catalysis, and adsorption of gases, as well as corrosion of metals (see pp. 13 and 18-19). T h e Varian LEED system consists of a crystal-target manipulator, crystal cleaning and preparation equipment, an electron optical system, a vacuum diffraction chamber, and some optional accessories for special needs. T h e heart of the LEED system, housed in the rectangular vacuum chamber shown here, is comprised of the electron optics system, the crystal manipulator, and the ion bombardment gun. T h e rectangular diffraction chamber is made of heliarc-welded, nonmagnetic stainless steel to assure vacuum reliability. Mounted on the chamber front is a 5.5-in. dia. glass viewport through which the diffraction spot pattern is observed and photographed. O n the sides of the chamber are four symmetrically located ports, two of these for crystal and ion-bombardment gun manipulation, while the other two are available for optional instrumentation. Crystal samples are mounted on a holder attached to the crystal manipulator within the diffraction chamber. The crystal manipulator features a unique universal motion feedthrough which allows rotation and linear movement during examination. The electron beam
which is electrostatically focused on the crystal target is operated between 10 and 475 volts, and from a fraction to 10 microamps. Beam voltage dispersion is nominally 0.2 volt, and its diameter a t the target is 1 mm., and clear diffraction patterns are effected down to beam voltages of 15 volts. T h e spherically shaped, phosphor-coated fluorescent screen, provides a n adequate viewing aperture of 3.5 in. for visual observation and photography of the white diffraction patterns. I n front of the fluorescent screen are two spherically shaped, 100-mesh, nickel-plated tungsten screens which provide about goyotransparency.
T h e control unit for electron optics provides u p to 475 volts of beam voltage, and voltage metering in 0-30-, 0-loo-, 0-300-, and 0-1000volt steps with outputs for a recorder and precision voltmeter. Emission current is monitored in 0-50- and 0-1000-ma. steps. Fluorescent screen voltage is adjustable from 0-7000 volts and is metered. Voltage regulation is hl%, and a safety interlock feature is provided to cut off filament and screen voltages should the pressure in the vacuum diffraction chamber, for any reason, rise over a preset value. (Continued on page 6 8 )
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The continual problem of surface cleaning in LEED studies is solved by the built-in crystal cleaning and preparation capability. Cleaning of the crystal target is performed within the vacuum diffraction chamber by gas reaction, direct resistance heating, ion bombardment, or a combination of these techniques. Gas inlet manifolding is included to admit small quantities of ultrapure gases for crystal cleaning, or in the case of gas-adsorption investigations, for the study itself. I n the case of nickel studies, carbon is removed from the surface by heating in an oxygen environment which effects formation of easily removable carbon monoxide. Any adsorbed oxygen is removed by subsequent heating in hydrogen, followed by vacuum heating to remove adsorbed hydrogen. For some crystals, cleaning is best accomplished by ion bombardment. A specially designed ion gun permits bombardment or sputter cleaning of the crystal surface with argon or other noble gas ions. Low ionbombardment energy and current density minimize the disturbance of surface structure. The ion beam is THE DISPERSANT controlled in the range from 140 to 375 volts with a maximum curOne minute, please! We assure you we don’t know how a MARASPERSE rent density of 2.5 microamps/ could be used to put a space ship in orbit but that’s no reason why we shouldn’t tell you some of the things we know a MARASPERSE will do sq. cm. and a nominal beam diameter for you here on Earth. of 1 cm. The vacuum system maintains For example: With MARASPERSE, low cost, more effective 10-l0 range pressure in the difdispersants, you can fraction chamber. Pure gases or 1. Increase the fluidity of a mass while maintaining the same gas mixtures are admitted to the solids content, chamber for cleaning or experimental 2. Increase the solids content of a mass without reducing purposes through a gas-inlet manifluidity or increasing viscosity, fold equipped with valves that facil3. Make uniform, stable dispersions of insoluble solids in itate selection of gas composition. water, and Cryotrapping rough unit and ion high4. Stabilize oil-in-water emulsions. vacuum unit provide 140 l./sec. pumping capacity. An ion-gage leak And these are only a few of the many uses for the MARASPERSES. For more information about the economy and verdetector obviates the external vacsatility of the Marasperses and other Marathon Chemicals from uum connection usually required Wood write for your copy of Bulletin No, 130. Use the coupon with conventional mass-spectrombelow. eter leak detection. *T/M Reg. American Can Company Optional accessories include custom design of the diffraction cham&D ber for special needs, a graphic lP7T CHEMICAL PRODUCTS S A L E S DEPT. pressure recorder, special flanges NEENAH, WISCONSIN and feedthroughs, a crystal isolation ___-________________-------------_--------------_------_----valve for experiments where crystals AMERICAN CAN COMPANY, CHEMICAL PRODUCTS SALES DEPARTMENT, NEENAH, WISCONSIN are exposed to corrosive gases, and P l e a s e send I n f o r m a t i o n File No, 1-7 a n d samples 0 of M o r a s p e r s e for use in the titanium sublimation pumping for f o l l o w i n g a p p l i c a t i o n ...................................................................................................... active gases such as oxygen, nitroNAME ............. ...................................................................... TITLE .......................................... gen, and carbon monoxide. Varian COMPANY ................................................... ............................................ 201 Associates, Inc.
Universal
AMERICAN CAN COMPANY
ADDRESS
.
............................................................................
Please attach to your company letterhead
Circle No. 39 on Readers’ Service Card 68
INDUSTRIAL A N D ENGINEERING CHEMISTRY
1-7
(Continued on poge 70)
A quicker way to copolymer design another acrylic monomer service from Rohm & Haas Glass temperature (T,)-the temperature at which an amorphous polymer changes from a hard, glassy state to a rubbery condition -lets you predict a polymer's hardness and other properties. Although it is not a difficult operation, calculating T, of a copolymer takes a lot of time . . . as indicated in the background of the photo above. To save you this time in computing T, of 100%-acrylic copolymers, and copolymers of acrylates or methacrylates com-
bined with other common monomers, Rohm & Haas provides the AcrylicGlassTemperatureAnalyzer. Recently revised, the Analyzer includes latest laboratory measurements. Get your revised copy by filling in the coupon. The Glass Temperature Analyzer is only one of many services Rohm & Haas offers to acrylic monomer users. Detailed description of all services is given in a bulletin available on request.
Monomers from Rohm & Haas:
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Write t o Dept. SP-14
ROHM
HA~AS .*II.O.L.*IA.C*
lelo,
Please send: 0 Revised Glass Temperature Analyzer Bulletin describin Acrylic Monomer services available f?om Rohm & Haas 0 Samples of following monomers
1 I I
I I I
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I
Methyl Acrylate Ethyl Acrylate Butyl Acrylate 2-Ethylhexyl Acrylate Methyl Methacrylate Ethyl Methacrylate Butyl Methacrylate Isobutyl Methacrylate Lauryl Methacrylate Stearyl Methacrylate Dimethylaminoethyl Methacrylate t-Butylarninoethyl Methacrylate Hydroxyethyl MethacryIate-30% Hydroxyethyl Methacrylate-96% Hydroxypropyl MethHydroxypropyl Methacrylate-S6% Butylene Dimethacrylate Glacial Acrylic Acid Glacial Methacrylic Acid Methacrylamide acrylate-40%
Circle No. 19
on Readers' Service Card
.
Dispense liquids Accurately, Automatically Every Time
ADDITIONAL NEW EQUIPMENT
Centrifugal Pump. Compact centrifugal p u m p made of titanium and molded polypropylene features 100 gal./min. pumping capacity, and design for long life when handling corrosive fluids. Pump, called Westec, has job-rated closedtype impeller designed to increase or decrease flow and pressure ratios independent of varying temperature. TVestern Technology, Inc.
End the drudgery o f repeated resettings and rem easu ri ng. The Man-0-pet, once set, dispenses any volJme from 2 cc to 30 cc with,n = l o l a t'me after time after tlme. Ideal in all fields where a preset volume has to be dispensed repeatealy. Lightweight. autoclavable, easily cleaned, chemica, y inert. can b e operated with one hand. Teflon coated stainless steel barrel eliminates stocking or freezing. Micrometer tvoe volume selector. No i i r i n g e or pipette needed.
71-646-01 Man-0-pet Automatic Pipettor complete with tubing, check valve and sinker.. each $27,95
.
202
Write for free descriptive bulletin.
Available t h r o u g h y o u r l a b o r a t o r y s u p p l y dealers
20
N. MOORE ST., DEPT. 562, N.Y. 13, N.Y.
Circle No. 34
on Readers' Service Card
WE ALSO MAKE:
SRL Pumps .-c
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Attrition Scrubbers AND OTHER ITEMS
Agitators & Conditioners DENVER solves the TOUGH agitating prob. terns-successfully! Dense slurries, fastsettling solids, large volume tanks, slurry holding, total leaching, solvent extraction, difficult mixing, abrasion, corrosion-these are areas of specialized experience and engineering at DENVER. Take advantage of
DENVER'S experience covering the complete range of agitation problems. Write for 68-page Agitator Specification Manual, No. AZ-Bl5, a complete engineering reference on agitation, includes extensive drawings and selection tables. Laboratory agitators also available.
Agitator Systcm. Double-motion agitator system for processing of heat-sensitive lubricants features jacketed kettle to assure more uniformly distributed heat transfer. Two concentric shafts of opposice rotation effect double motion. Patterson Industries, Inc. 207
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DENVER EQUIPMENT COMPANY 1400 SEVENTEENTH STREET DENVER, COLORADO 80217 Circle No. 9 on Readers' Service Card
70
Centrifugal Separator. Horizontal centrifugal separator utilizes the thin-layer principle for operation to separate slurries with minimum of 50% solids and particle sizes larger than 200 mesh. Unit can recoxer dry solids, liquid phase, or both solids and liquids. Allis-Chal203 mers, Inc. Split-Case Centrifugal Pump. Double-suction, horizontal, splitcase centrifugal pumps has special design features for greater wear and efficiency. T h e unit is lighter in weight with heavier pressure walls and requires less space than those formerly available from this 204 producer. Crane Co. Swivel Joint. Lightweight plane swivel joint features balanced pressure design which permits swiveling action of hose connections without binding or twisting of the hose lines. Thus, hose lengths connecting joint to process equipment are reduced as much as 30 %. Aeroquip Corp. 205 Exhaust Smoke Eliminator. Vacuum p u m p exhaust smoke eliminator is capable of removing 99.95% of all smoke particles, because of two-stage element design which effects double cleaning of gases. Beach-Russ Co. 206
I N D U S T R I A L A N D ENGINEERING C H E M I S T R Y
PHONE 303/2444466
M o r e information i s as near as your mailbox. Just circle the number of the i t e m in which you a r e interested on the Readers' Information Card.
LITERATURE
Nickel-Clad Pipe. Gives technical information on piping and fittings for chemical, petrochemical, paper and pulp, and pharmaceutical applications. Bart Manufacturing Corp. 208
a PENNSALT DEVELOPMENT CHEMICALS
LIQUID DIALKYL THIOUREA Humidity - aging resistance of rigid polyurethane foams improved by new additive Experimental work in the Applications Laboratory a t the Pennsalt Technological Center has demonstrated the ability o f Liquid Dialkyl Thiourea to improve humidity-aging resistance significantly when used as a partial replacement f o r the polyol portion o f one-shot rigid polyurethane foams.
This work has been summarized i n our Bulletin
S-200,which
describes
the experimental techniques employed, and gives examples of the foam formulations used.
W r i t e for Pennsalt Bulletin S-200 and a sample for your evaluation.
\
PENNSALT
CHEMICALS W EQUIPMENT
PRODUCT DEVELOPMENT DEPARTMENT PENNSALT CHEMICALS CORPORATION 3 PENN CENTER PHILA., PA. 191 02 Circle No. 16 on Readers' Service Card
Pilot Coating System. Illustrates a unit for continuous coating and impregnating of woven cord fabrics. Also contains basic information on continuous coating and laminating. C. A. Litzler Co., Inc. 209 Dehydrators. Covers a complete line of electric heat reaotivated and heaterless desiccant compressed gas dehydra210 tors. Kahn and Co., Inc. Pressure Snubber. Presents a sealed, isolated system to protect Bourdon instruments from corrosive liquids, gases, and viscous materials. Includes complete specifications and applications. Chemiquip Co. 211 Air Compressors. Covers two-stage, air cooled V-belt compressors in 25 h.p. and 30 h.p. sizes. Kellogg-American, Inc. 212
Industrial Glass. Covers a range of glass equipment for industrial and chemical processing applications. Also lists pneumatic and magnetic operated control valves with glass-Teflon construction. Corning Glass Works. 213 Polycarbonate Applications. Gives various methods of joining polycarbonate parts to each other, or to other plastic or metal parts. Mobay Chemical Co. 214 Tubular Fans. Presents complete performance data for cenitrifugal fans designed to provide straight-through airflow. Bull. 333A. Aerovent Fan Co. 215
Refrigerated Air Dryers. Presents advantages of a noncycling refrigeration system to produce instrument quality compressed air. Bull. 0200-1. Hanikson Corp. 216 Vertical Pumps. Illustrates a line of industrial service pumps for liquid transfer applications including tanks, sumps, and cooling tower basins. Peerless Pump, FMC Corp. 217 Storage Tanks. Covers filament wound, Fiberglas reinforced tanks for noncontaminating storage of chemi218 cals. Amercoat Corp. Water Conditioning. Presents equip ment for commercial and industrial applications. Also describes units for automatic control. Water Refining Co. 219
Mixing Equipment. Describes a line of mixers for medium to high density materials. Read Corp. 220 Circle
No. 13 on Readers' Service Card
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