ment fall into two general classifica tions: trapping devices in which gases are captured and retained within the vacuum system, and momentumtransferring machines which remove gases from the system and exhaust them to the environment. Cryosorption pumps and arrays, cryopumps, and ion-gettering pumps belong to the trapping class. Mechanical rough pumps, oil-diffusion pumps, and steam ejectors belong to the momentumtransferring class. Steam ejectors can attain a vacuum of 10~2 torr; mechanical rough pumps, 10 - 3 torr; and oil-diffusion pumps 10~7 torr (with cryogenic trapping, even lower). In the trap ping class, ion-gettering pumps attain a vacuum of 10 - 1 0 to 10~12 torr, and cryopumps can attain vacuums of 10 - 1 1 torr. Cryosorption goes to 10" 13 to 10 - 1 4 . For comparison, the pressure at 800 miles out from the earth's surface is about 1 0 1 1 torr; on the surface of the moon, it's about 1 0 1 5 torr. At 10~1δ torr there are about 30 molecules of gas per c c ; at sea-level pressure there are about 25 Χ 10 1 8 molecules of air per cubic centimeter. Which pumping system or combina tion of pumps to use for a particular application involves a number of vari ables—capital cost vs. operating cost, for example, and vacuum level re quired, tolerance of the intended ap plication to hydrocarbon contamina tion, chamber size, and gases to be pumped. For certain uses, Linde be lieves its cryosorption systems offer distinct advantages. For larger sized, hard-vacuum chambers—4 to 5 ft. in diameter and up—Heraeus-Engelhard says the cryosorption systems are much more economical than other types. For applications such as growing crys tals, cleaving crystals under vacuum, materials studies on cold welding, and performance of bearings, which may require ultraclean vacuums, Linde be lieves its system offers distinct ad vantages. Another area in which the firm believes the cryosorption system is especially suitable is in pumping hydrogen and helium gas. Clean. For some of these uses, other pumping systems or combina tions might perform the job, but not as well, Linde believes. Because oildiffusion pumps contribute hydrocar bons to a vacuum system they must be augmented with refrigerated baf fles or traps to maintain cleanliness in the system. But, Linde says, because
these baffles or traps are never com pletely efficient, absolute absence of hydrocarbons is not achieved as it is with cryosorption pumps. Ion-getter ing pumps have the disadvantage of generating methane in small quanti ties. Both cryopumping and cryosorption depend on cryogenically cooled gas for their operation. Thus, they are both essentially nonmechanical systems. There the similarity ends, since cryo pumping depends on gas molecules condensing on a refrigerated surface, and cryosorption physically captures the molecules in a refrigerated adsorp tion material. For condensation to take place in the cryopump, however, the plate must be cooled below the boiling point of the gaseous components. Even at the temperature of liquid helium—4.2° K.—the vapor pressure of hydrogen, one of the most common gases present, is relatively high. At 20° K. it is one atmosphere. Trapped. With cryosorption, the molecules are trapped. A suitably selected molecular sieve when refrig erated to the normal boiling point of the gas to be adsorbed will exhibit a high adsoiptive capacity for the gas. Nitrogen and oxygen are adsorbed be low 77° K., hydrogen at 20° K., and helium at 4.2° K. Thus if liquid or cold gaseous helium is used to cool the molecular sieve all of these gases can be adsorbed. For the roughing range, Linde is making pumps containing beds of mo lecular sieve of from 2 to 125 lb. for evacuating volumes ranging from 2.5 to 150 cu. ft. Multiples would in crease the volume capability. These all use liquid nitrogen and are for use external to the vacuum chamber. For the hard-vacuum range Linde makes its arrays. The firm says it took about two years and considerable computer time to arrive at the final, optimal design for these units. They are placed directly in the vacuum chamber. The sieve plate is cooled with liquid helium, or in the larger sizes, cold helium gas, and the baffles and shields are cooled with helium vent gas and liquid nitrogen. The smallest of these arrays, the SHe-8, has an effective pumping speed at the pump inlet of 1000 liters per second for hydrogen, constant between 10~8 and 10~12 torr. The largest array, the SHe-25, has a pumping speed of 13,000 liters per second for hydrogen at 10~8 torr.
New Centrifuges Bow at Chem Show Komline-Sanderson and Swenson Evaporator are new suppliers Visitors to the just-ended 30th Exposi tion of Chemical Industries in New York who had an eye out for areas of equipment activity found one in cen trifuges. At least two companies are entering the market with newly im ported units, and others have come out with new models that expand their lines to higher capacities. New names being added to the list of centrifuge suppliers are KomlineSanderson Engineering Corp., Peapack, N.J., which is marketing the K-S/Heine continuous pusher cen trifuge, and Swenson Evaporator, Chi cago, which is importing the SwensonKMI oscillating centrifuge. Mean while, Milwaukee's Allis-Chalmers and Centrico (Englewood, N.J.) have both added high-capacity units. Komline-Sanderson and Swenson offer two different approaches to pusher type centrifuges. Basically, a pusher centrifuge, mounted horizon tally, feeds slurry to the rear of a spinning basket. A reciprocating pusher moves deposited solids out along the periphery of the basket. As they move along the surface, the sol ids may pass through a wash zone if one is required, eventually moving to the edge of the basket where they drop off to discharge. Cam. Pushers on conventional pusher centrifuges are powered hydraulically. Komline-Sanderson's unit, however, has a mechanically
WASH NOZZLES. Komline-Sanderson's C. J. Gakeler points out the wash nozzle arrangement of the company's K-S/Heine pusher type centrifuge to John M. Laferty of Sylvania Electric DEC.
13, 196 5 C & E N
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vapor pressure
operated pusher driven by the main motor. Controlled by a cam, the pusher speed increases as the stroke moves forward and the pusher with draws quickly on the back stroke. This, the company says, reduces axial compression of the cake and results in less damage to fragile crystals. The use of a mechanical coupling, the company also points out, leads to low power consumption. With the cam, a controlled push can be de veloped, which eliminates the need for changing stroke rate for different ma terials. Another feature of the centrifuge is its basket. Solids are introduced at an imperforated section of basket and the pusher operates on an unperforated raceway. This, the company says, keeps loss of solids to the filtrate low. Komline-Sanderson is currently im porting two sizes—12-in. diameter and 24-in. diameter. The company plans, however, to make the centrifuges it self under manufacturing rights and will then have larger sizes available. The Swenson-KMI centrifuge is a further departure from conventional design. With this unit, the basket oscillates, while the pusher plate re mains stationary. An exciting unit and a large resonance spring induce the basket to oscillate at about 1500 cycles per minute. The basket in the Swenson-KMI unit has a short cylindrical section and a conical section. The cone angle
accurately1 with
FUSED QUARTZ
precision pressure gage • high resolution — 1 to 1 micron ι • wider ranges — to 500 psi • for high temperature — to 1000° F • for cryogenic applica tions — liquid He, O s , No, etc. • for corrosive applica tions — chlorine, bro mine, etc.
chosen depends on the application. Because of the oscillating action and the short basket, Svvenson says, crystal breakage is extremely low. Allis-Chalmers' Model 4000 centrif ugal separator is designed to separate slurries having a minimum of 10't solids in a 325- to 1 / 4 -in. mesh range. The low-cost (about $12,000) unit can be used for dewatering, drying, purging, screening, and washing. Larger than the company's earlier Model 2750, which has a 27-in. di ameter basket, the new unit has a 40in. diameter basket. Solids move down the basket because of its sloping walls. Three basket assemblies—with angles of 26°, 30°, and 3 4 ° - a r e avail able, depending on the particular ap plication. The basket, Allis-Chalmers points out, is made of stainless steel and has a welded-on blanket of 4mesh, stainless steel wire. A 180 gal.-per-minute Westfalia desludger, dubbed ULTRA SAM, is among several new units added to Centrico's line. The unit is designed to clarify products containing high amounts of solids and has a capacity more than 50r/r greater than the com pany's BIG SAM. Centrico has also added the SIG 15007, a nozzle bowl centrifuge with an extremely high throughput—up to 440 gal. per min ute. A full range of nozzle sizes, Centrico says, makes it possible for the unit to process materials with widely varying solids contents.
TI Precision Pressure Gages are faster, easier to use — avail able for table top or relay rack mounting in manual or servonulling models. Fused quartz Precision Gages, Controllers and Systems are un excelled in any application re quiring precise measurement and control of pressure. Write for Bulletin S-141-6 TEXAS I N S T R U M E N T S I N C O R P O R A T E D Ψ. O. BOX 66027 HOUSTON. TEXAS 77Ο0β 7 RUC VERSONNEX GENEVA, SWITZERLAND
_. .
714
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D E C . 13, 196 5
SEPARATOR. P. P. Strich of Allis-Chalmers (left) and J. Harry Donald of U.S. Rub ber's chemical division examine a catalog that describes the high-capacity features of Allis-Chalmers' new centrifugal separator
To help keep her wash bright we spray dry our Sodium Tripolyphosphate To help you get that extra strength you want in your detergents, we include a special spray drying operation in our process before calcining. This is your assurance that when you order sodium tripolyphosphate from us you get pure, high strength material. The uniform granules of dry, free-flowing AA
Quality STP blend smoothly, evenly and easily with other detergent materials. The hollow, spherical structures are higher in bulk . . . provide greater surface area and ready high solubility. For a sample, trial shipment, data sheets, or a complete product catalog, write:
AMERICAN AGRICULTURAL CHEMICAL COMPANY I N D U S T R I A L SALES
Dept.E-12, 100 C h u r c h Street, N e w York, New York 10007
C&EN
EQUIPMENT
PROGRESS REPORT
These items have all been mentioned editorially in C&EN in the past month. If you haven't already sent fory information on them, just check the appropriate key numbers on the coupon on page 54, and C&EN s Readers' Information Service will forward your request to the manufacturer.
INSTRUMENTS AND CONTROL . . . Product
Company
Gas elution analyzer
Ε 60
Spectrophotometer
Ε 61
Gel-permeation assembly
Ε 62
Analytic Systems Co. Pasadena, Calif. Phoenix Precision Instrument Co. Chicago, III. Waters Associates, Inc. Framingham, Mass.
Features Separates and measures components of a sample stream Capable of measuring adsorption changes of 3 Χ 1 0 8 optical density unit in turbid media For obtaining both molecular weight dis tribution and gram quantities of poly mer fractions
EQUIPMENT AND LABWARE . . . Sieve (Sonic Sifter)
Ε 63
Allen-Bradley Co. Milwaukee, Wis.
Continuous blender
Ε 64
Allis-Chalmers Milwaukee, Wis.
Tubing
Ε 65
Laboratory rotator
Ε 66
Amtec Products Co. Gardena, Calif. Fisher Scientific Co. Pittsburgh, Pa. Frigistors, Ltd. Montreal, Que. Fuller Co. Catasauqua, Pa.
Thermocouple reference chambers Ε 67 Heat-treating system
Ε 68
TLC apparatus
Ε 69
Solvent refiners
Ε 70
Pyro-decomposition system
Ε 71
Platinum resistance sensor
Ε 72
Arc heater (Marc 30)
Ε 73
Reinforced Tanks Gain New Material, Maker A new reinforced-polyester material and a new manufacturer of reinforcedpolyester tanks marked advances in materials of construction at the Ex position of Chemical Industries in New York. Haveg 7410, a polyester reinforced with polypropylene fila ment, comes from Haveg. OwensCorning Fiber glas has formed a new division—noncorrosive products divi sion—to make and market glass fiberreinforced polyester storage tanks. The main feature of its new mate rial, Haveg says, is that it is chemically 50
C&EN
DEC. 13, 1965
Kensington Scientific Corp. Oakland, Calif. New Jersey Ultrasonic Corp. Rochelle Park, N.J. Prenco Division Pickands Mather & Co. Detroit, Mich. Rosemount Engineering Co. Minneapolis, Minn. Westinghouse Electric Corp. Pittsburgh, Pa.
resistant throughout its entire mass. The company points out that the pre cautions taken with glass fiber rein forcing to prevent exposure of the glass are unnecessary. Haveg's tanks are cylindrical with elliptical covers and bottoms and range in diameter from 4 to 10 ft. and in capacities from 500 to 7800 gal. Owens-Corning Fiberglas is cur rently supplying 2000- and 3000-gal. open-top and 4000- and 6000-gal. closed-top tanks. When its new plant at Huntingdon, Pa., gets into opera tion early next year, the line will in clude diameters from 6 to H V 2 ft. and capacities from 1000 to 22,000 gal.
Uses a vertical column of air to move the material being sifted through a set of 3-in.-diameter sieves Uses multisplitting technique for use on materials that differ in particle size, density, and shape Combines stainless steel (outside) and Teflon (inside) for corrosive uses Uses a horizontal rack rather than a circular turntable For use where temperatures have to be measured continuously and accurately Fluidized-bed type for calcining, react ing, decomposing, drying, cooling, subliming, and particle growth For applying wedge-shaped adsorbent layers to glass or film For purifying solvents Consumes textile mill finishing wastes For measuring temperatures to 2500° F. For investigating high-temperature chemcal reactions
CHEM SHOW BRIEFS Liquid-solid separator for industrial effluent cleanup has been developed by Southwestern Engineering Co., Los Angeles. It is intended for applica tions involving bulky, fibrous solids. Called the Whirlpool separator, it has a three-dimensional gyratory motion that moves material in a whirlpool pattern toward an opening in the center of a screen. Ε 74
Pressure vessel closures have been designed by Autoclave Engineers, Erie, Pa., with a new resilient thread
Can you identify chromalogram peaK 2?
The lR-102 can...almost as last as you can say, "Beckman lR-102 infrared spectrophotometer:' Peak 2 is isopropyl acetate. And the Beckman IR-102 Infrared Spectropho tometer made the identifying infrared scan of this peak in just five seconds, taking the 0.6 microliter sample directly from a chromatographic column. It can also give you the infrared spectra of each of the other peaks at the same rate. Five seconds is all it takes to scan from 2.5 to 14.5 microns when your chromatograph is connected to the IR-102 Spectrophotometer. The IR-102 was primarily designed for use with gas chromatographs. It allows you to identify components as they come from your gas chromato graphic column, even with fast eluting samples. It eliminates trapping, trans ferring, and condensing problems because it handles samples in the same
state as a chromatograph —as a hot vapor. Its high sensitivity allows analysis with fractional microliter volumes and submilligram quantities. And, the IR-102 is adaptable to any gas chromatograph. In addition to identifying complex mixtures by rapid scan infrared, the IR-102 can be used to complement the gas chromatograph as a specific detector. It can monitor fractions at a fixed wavelength, giving data on specific functional groups or on isomers that cannot be separated chromatographically. Total analysis of unknown mixtures is no longer a problem; your gas chromatograph and the IR-102 are a natural team. Whether you already have a chromatograph or are about to
get one, this instrument is a must for your laboratory. For more information on the IR-102, write for Data File IR-166. Or contact your local Beckman Sales Engineer. He'll be glad to show you how to make an infrared scan almost as fast as you can say, "Beckman IR-102 Infrared Spectrophotometer." The IR-102 employs a circular variable interference filter developed and manufactured to Beckman specifi cations by Optical Coating Laboratory, Inc., of Santa Rosa, California.
I N S T R U M E N T S , INC. SCIENTIFIC AND PROCESS INSTRUMENTS DIVISION FULLERTON, CALIFORNIA · 92634 INTERNATIONAL
S U B S I D I A R I E S : GENEVA; M U N I C H ;
G L E N R O T H E S , S C O T L A N D ; T O K Y O ; P A R I S ; C A P E T O W N ; LONDON"
C&ΕΝ
51
New Equipment from Matheson
Ultra-High Purity Hydrogen Generator Produces dry hydrogen under pressure for less than H per 100 liters. Impurities less than 1:100,000,000. Eliminates contamination possibility, unit is especially applicable for gas chromatography and semi-conductor work. Generator operates on new principle and is self regulating. Uses only water & electrical energy. Assures continuous hydrogen at pressures to 60 p.s.i.g. Rated capacity: 150 milliliters per minute. (0.31 scfh.) Hydrogen is produced as required to rated capacity. Easy to install & operate. Needs no maintenance. Generator consists of electrolytic cell, rectifier, regulating valves & switches. Electrolytic cell anode is nickel; cathode is bundle of palladium-alloy tubes. Electrolyte is strong alkali. During electrolysis, oxygen collects at anode and is vented to atmosphere. Ionic hydrogen is deposited at cathode. Ions drawn by electrolytic solution pressure penetrate tubes and recombine to form molecular hydrogen under pressure. Mail coupon for data.
Mass Flowmeter Highly accurate and stable direct reading unit for wide range of flow rates for practically all gases. Needs no ambient temperature correction from 40°F. to 200°F. Needs no gas pressure correction from 0.1 to 250 p.s.i.a.; 2% accuracy in these ranges. Measures gas flow down to 0.01 standard cc/min. even for hydrogen or helium. Measurement repeatability within 1 % . Can be used with recorders. Output signal approximately 0-2 mv. d-c. Once installed, needs no recalibration. Circuity is 100% solid state for maximum reliability. Flow transducer withstands extreme vacuum, pressure and flow rates Comes in 4 basic flow ranges. Mail coupon for data.
New Helium Diffusion Cell Purifier Produces low-cost, ultra-pure helium continuously from commercial cylinder helium without use of liquid nitrogen-cooled absorbents. Total impurity levels as low as 1:2,000,000. Produces pure helium at 1% the cost of Research Grade helium yet 10 to 20 times purer. Output of pure helium up to 450 cc/min (0.95 CFH), with inlet pressure of 1500 p.s.i.g. Even at cylinder pressures as low as 200 p.s.i.g., flow rates sufficient for most gas chromatography applications (50 cc/min) are realized. (See graph.) May be installed in any position. Supplied complete with pressure regulator to attach to CGA 590 standard helium cylinder and high pressure flexible metal transfer line.
Mail Coupon Now! The Matheson Company, Inc., P.O. Box 85, East Rutherford, N.J. Please send the following literature: • Ultra-High Purity Hydrogen Generator Π Mass Flowmeter Π Helium Diffusion Cell Purifier Name Firm Add ress City
. State
Zip
n/IATHESON P.O. Box 85, East Rutherford, New Jersey Plants in East Rutherford, N.J.; Joliet, III.; La Porte, Texas; Morrow, Ga.; Newark, Calif. · Matheson of Canada, Whitby, Ont.
52
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design. The thread, a form of spring, more evenly distributes stresses across the entire length of the closure. This, the company says, eliminates the stress concentration on the bottom one or two threads—a common cause of failure in conventional threaded clos ures. Ε 75
Canned pump from Crane Co.'s Chempump Division, Warrington, Pa., conforms to AVS (American Volun tary Standards) dimensional require ments. The centrifugal pump, Model GVBS, is designed to handle corrosive, toxic, explosive, radioactive, and other fluids at pressures to 300 p.s.i. Ε 76
ford, Conn. The company's first unit has plastic leaves with enclosing sleeves of woven monofilament mate rial, natural fabrics, or metal screens, precoated with filter aids. Ε 77
Packaging systems for flexible con tainers, rigid containers, and self con tainers such as bales will be a de parture for Howe Richardson Scale Co., Clifton, N J . System functions include complete materials handling Ε 78 and packaging.
Further information on keyed Equipment items is readily available . . .
Vacuum filters represent a new field for Croll-Reynolds Engineering, Stam
r%
I
f
i
r
••
Please discard all old gas catalogs and send for this new o n e . . .
Use handy coupon on page 54
Ο
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D e c e m b e r 13, 1965
Readers Information Service Use this h a n d y self-mailer to o b t a i n further information or literature. Simply mark t h e i t e m s desired, fill o u t t h e i n f o r m a t i o n r e q u e s t e d , clip t h e c o u p o n , fold, s t a p l e , a n d mail.
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Your Title: YOUR FUNCTIONS (Maximum of 2, please.) Α Β C D Ε F
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Many new listings a n d a greatly e x p a n d e d e q u i p m e n t line m a k e this n e w c a t a l o g a m u s t for l a b or p l a n t .
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Your industry: A ( ) Engineering and Construction Β ( ) Food and Kindred Products C ( ) Textile Mill Products D ( ) Paper and Allied Products Ε ( ) Government F ( ) Chemicals and Allied Products G ( ) Elastomers, Polymers, Plasticizers H ( ) Drugs I ( ) Detergents, Cosmetics, Specialties J ( ) Paints, Varnishes, etc.
Κ ( ) Petroleum Réf., Asphalts, Lubricants L ( ) Rubber and Plastic Products M ( ) Independent Laboratories Ν ( ) Consultants 0 ( ) Primary Metal Industries Ρ ( ) Fabricated Metal Products Q ( ) Machinery and Equipment R ( ) Transportation Equipment S ( ) Instruments and Controls Τ ( ) Education
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MATHESOIU P.O. Box 8 5 , East R u t h e r f o r d , Ν J .
Plants in East Rutherford, N.J.; Joliet, III.; La Porte, Texas; Morrow, Ga.; Newark, Cal.
DEC.
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