Engineering News : Page 7 of 10

inadequate control of empty cars. To improve speed control, designers added LIMs and braking magnets. To prevent overloads they installed harmonic line filters. And to solve temperature-induced belt stretch, the system is now warmed daily.

Although intended to serve all three terminals, only United Airlines-DIA's largest tenant-fully utilizes the baggage system. Others exploit small portions of it with the option to expand usage later.

DIA itself inspires description with superlatives-or obscenities. It covers the most land (53 square miles), supports the tallest control tower (327 feet), has some of the thickest runways, and at $4.9-billion dollars is the most expensive US public works project ever.

Oh, and of course it houses the most expensive ($230-mil) automated baggage handling system ever conceived. As it turns out, BAE's biggest mistake may not have been in engineering, but in public relations. Says Di Fonso: "The first time you push the button on anything, you're bringing yourself nothing but grief by doing it in front of an audience."

KEY SUPPLIERS
PRODUCT SUPPLIER LOCATION

LINEAR INDUCTION MOTORS

CALDWELL ELECTRIC

WACO, TX

ROTARY INDUCTION MOTORS

BALDOR ELECTRIC

FT. SMITH, AR

GEAR REDUCERS

MORSE

FLORENCE, KY

CLUTCH BRAKES

WARNER ELECTRICS

BELOIT, IL

TIMING BELTS

GATES RUBBER

DENVER, CO

COMPUTERS

TEXAS MICROSYSTEMS

HOUSTON, TX

PROGRAMMABLE CONTROLLERS

SQUARE D CO.

MILWAUKEE, WI

ELECTRICAL CONTROLS

ALLEN BRADLEY CO.

MILWAUKEE, WI

LASER BAR CODE SCANNERS

LAZER DATA CORP.

SANFORD, FL

CONVEYOR BELTING

GEORGIA DUCK

SCOTTDALE, GA

BEARINGS

MORSE SEALMASTER

FLORENCE, KY

POWER TURN CONVEYORS

PORTEC

CANON CITY, CO

EXTENDIBLE CONVEYORS

CALJAN AMERICA

DENVER, CO

ELECTRICAL CABINETS

HOFFMAN ENGINEERING

ANOKA, MI

RFID SUBSYSTEMS

INDALA

SAN JOSE, CA

VERTICAL LIFTS

P FLOW INDUSTRIES

MILWAUKEE, WI

WHEEL TREADS

AMERICAN URETHANE

GAMBRILLS, MD


Spacehab test mission drives valve redesign

Huntsville, AL -Engineering a manufacturing process can be difficult enough. Try designing one where all the components operate well in zero gravity and meet NASA's strict manned-flight qualifications.

Dr. James E. Smith of the University of Alabama confronted this problem and met it. His job: Create a liquid-phase sintering process that could fly on NASA's first Spacehab mission on the shuttle Endeavor in 1993. And in the process, Smith compelled his suppliers to redesign their components to meet his unconventional needs.

In liquid-phase sintering, two or more metal powders are compacted into a billet and heated above the melting point of one of the metals; another remains as an unmelted constituent. An argon gas purge removes driven-off gasses and cools the furnace. For this particular piece of support hardware, Smith required a solenoid valve in the line and so he contacted New Jersey-based Automatic Switch Co. (ASCO).

ASCO's design process started with magnetic analysis performed in ANSOFT. The analysis allowed the supplier to optimize solenoid efficiency by reshaping magnetic, stainless-steel pole pieces. The final pole shape provided the force necessary to operate the valve in space.

The new design also combined the valve base with the solenoid base assembly. To accomplish this, ASCO replaced Smith's spec for 1/8-inch NPT connections with integrated stainless-steel tubing. This alone saved about 1 lb. of valve weight.

The valves were then machined

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