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May 24th, 2004 - Volume 4 Issue 11
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Spotlight
On . . .
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News of Interest
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Sensors
Expo & Conference |
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Sensors Expo & Conference is the largest gathering of sensor and sensor-related solutions, systems, and buyers in North America. |
The 2004 four-day program features highly regarded industry experts presenting full- and half-day workshops with over 40 sessions focused on a wide range of sensor topics: biosensors, wireless sensor networks, nanotechnology, MEMS/MST, smart solutions, and industrial automation. Click here for more information. |
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Looking For . . .
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Current sources provide reliable current levels for electrical component testing and for powering specialized components such as lasers. Current (or power) levels will remain constant during variation of load impedance. Current sources are used in a wide variety of test applications such as relays, circuit breakers, satellite components, and power meters. Current source styles include PCB mount, printed circuit board or card mount, laboratory bench or portable configuration, rack mount, DIN rail mount, and freestanding or cabinet mount. You will find contact information for 37 manufacturers in this category. Click here to search for Current Sources by Spec. Hydraulic brakes are assemblies consisting of elements for the slowing or stopping of shafts in equipment drives. Hydraulic power is required to activate the brake. Brake types available are friction type or toothed. The most important parameters to consider when searching for hydraulic brakes are the operating specifications. These include torque rating, power, speed, and maximum pressure. The maximum torque rating for the brake should equal or exceed application requirement. The maximum power rating for the brake is given in HP. Maximum rotary speed rating of the brake is specified in rotations per minute (rpm). Maximum pressure for a hydraulic brake is specified in psi. You will find contact information for 38 manufacturers in this category. Click here to search for Hydraulic Brakes by Spec. Plug valves
date back to ancient times, where they were developed for use in citywide Roman
plumbing systems. Today, they remain one of the most widely used valves for both
on/off and throttling services. Their design is fairly simple; the body is comprised
of three main parts: body, cover and plug. The plug is a cylindrical, tapered,
or generally cone-shaped device that can be raised or lowered within the seat
to maintain, restrict or completely shut off flow. The valve is opened by rotation,
with the plug itself being the only element that is capable of movement. Early
models of plug valves used metal-to-metal seals that were nonlubricated. This
design is still used, but problems with galling and sticking limit their usefulness.
The use of lubricant between the plug face and the seat eliminates most of these
problems. The lubricant helps to control leakage around the plug, reduces wear
between the valve contact surfaces, and slightly lifts the plug to reduce the
operating torque required to operate the valve. You will find contact information
for 71 manufacturers in this category. Click here to search for Plug Valves by Spec. |
Product
and component testing is the evaluation of a finished product or component through
performance in electrical, life, environmental exposure, dynamic, ergonomic or
other specialized tests. Also testing to standards such as UL 489, CE, ISO or
MIL-STD 810. Typically a battery of different tests are employed in the evaluation
process. Capabilities and services, products tested and certifications and approvals
are all important considerations when specifying providers of product testing
services. You will find contact information for 433 manufacturers in this category. Click here to search for Product and Component Testing Services by Spec. Radiometers are calibrated and provide a measurement of the amount of light power incident on the detector. They are univariate devices and do not distinguish between light of different wavelengths. Radiometer performance parameters are important to consider when specifying radiometers. These parameters include wavelength range, sensor diameter, power range, accuracy, resolution, operating temperature range, and humidity range. The wavelength range specifies the range the radiometer can detect over. The sensor diameter refers to the diameter of the active part of the sensor. The power range is the power per unit area range of the radiometer. The accuracy of the radiometer is represented as a percentage. The resolution of the detector is a measure of how sensitive it is. The operating temperature is the recommended operating temperature range for the radiometer. The humidity range is the operating humidity range for the radiometer. You will find contact information for 53 manufacturers in this category. Click here to search for Radiometers by Spec. Roll forming is a metal forming process used to create shapes of uniform cross section. In the roll forming process, metal in sheet, strip, or coiled form is fed between successive pairs of rolls that progressively bend and form it until the desired shape and cross section is obtained. The roll forming process adds strength and rigidity to lightweight materials (such as aluminum brass, copper, lead, zinc and tin), composites, some heavier ferrous metals, and specialized alloys and exotic metals (such as beryllium copper, beryllium nickel, niobium, tantalum, and titanium). You will find contact information for 70 manufacturers
in this category. Click here to search for Roll Forming by Spec. |
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Spotlight On . . .
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| Galil
Motion Controls On-Line Motion Control Tutorials from Galil |
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Click here to watch the tutorials at no charge. |
With over 350,000 controllers operating worldwide, Galil is the leader in cost-effective, high-performance motion control. Call Galil at 800-377-6329 or request a complimentary copy of Galil's 2004 catalog here. Click here to learn more about Galil Motion Controls or send an e-mail for additional information. |
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Technical Article Spotlight
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"As most engineers and plant managers realize, O-ring failures can be critical. The ability to troubleshoot these problems can save precious time in getting production equipment back on line, or redesigning the sealing system of a company's product. An O-ring is a 'simple' device often specified or installed as an afterthought – simple that is until it fails. The apparent simplicity of an O-ring should never be confused with the complexity of its function: a device that in deformation must balance the many effects of chemical attack, friction, pressure and temperature while maintaining the fluid integrity of the system. Clearly, then, the modes of failure are case specific and varied across the range of O-ring applications. Both mechanical and chemical causes of failure are revealed in the visual patterns of the failed O-ring. The following is a basic guide for identification of the visual evidence of O-ring failure and the interpretation of that evidence in terms of possible causes. |
Seals affected by extrusion and nibbling appear as if many small bites have been taken from the O-ring on the downstream or low-pressure side. These tiny bites are commonly found on the ring circumference and are typical of the failures that occur in high-pressure systems. The biting is often caused by pressure spikes which force the elastomer into the extrusion gap and shear off small pieces of the seal wall. Materials with low tear strength and low durometer (hardness) such as silicones and fluorosilicones are more susceptible to failures of this type, while higher durometer and high tear strength materials such as carboxylated nitrile and urethane are less prone to extrusion and nibbling..." Apple Rubber Products, Inc., a leading designer and manufacturer of seals and sealing devices, provided this article. Links: |
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The Challenge
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This edition's Challenge is brought to you by HBM, a leader in measurement and data acquisition (DAQ), and sensor/transducer technology. Test Your Knowledge... Question: The question presented in the last edition of the newsletter was: So you think you're a technology guru, eh? You look around at the amazing technology at our fingertips and pity those who came before us and lived without the conveniences we so often take for granted. Well, take this short quiz and then we'll see how superior you feel! 1. When was central heating first developed? Answer:
The first known central heating systems were used in about 1200 B.C. In 1954,
British archeologists unearthed a palace in Turkey dating from this period that
had ducts running beneath the floors for a central heating plant. Central heating
then disappeared and was developed again by the Romans in about 80 BC. They called
their systems hypocausts.. It disappeared again in the eleventh century and
was not revived until modern times. Answer:
The Phoenicians developed clear glass windowpanes in the first century BC, and
clear glass windows of the modern type were brought into common use by the Romans
in the first century AD. Answer:
The Greeks used complex mechanical computers to tell the motion of the planets
and other astronomical bodies. The only such actual device ever unearthed was
excavated in 1901 from a shipwreck dating from about 76 B.C. According to Derek
J. deSolla Price, who deciphered its design: “Consisting of a box with
dials on the outside and a very complex assembly of gear wheels mounted within,
it must have resembled a well- made 18th-century clock. Doors hinged to the box
served to protect the dials, and on all available surfaces of box, doors and dials
there were long Greek inscriptions describing the operation and construction of
the instrument. At least 20 gear wheels of the mechanism have been preserved,
including a very sophisticated assembly of gears that were mounted eccentrically
on a turntable and probably functioned as a sort of epicyclic or differential,
gear-system.” Visit: |
4. When was hydraulic cement (cures underwater) invented and first used? Answer:
Hydraulic cement (cement that hardens under water) was discovered by the Romans,
who called it pulvus puteolanus, in about the 3rd century B.C. Many of their later
structures are built primarily of this cement, with a thin facing of stone. 5. When was the first battery invented? Answer: You’re thinking “Aha! I know this one! Volta, in 1800 – right?” Sorry. In 1936, archeologists discovered near Baghdad a small clay jar. Inside the jar was a copper cylinder sealed with asphalt, and inside the cylinder was an iron rod. When filled with wine, vinegar, or another electrolytic solution, a replica of the battery puts out about 1.1 volts. Since the original discovery, similar jars have been found elsewhere in modern-day Iraq. It is believed that they were used to electroplate metals. Visit: New Question: Your boss gives you the task of analyzing a 12 ft. long communications whip antenna to see if it will snap in field use due to weather. You know the material properties, the geometry as a function of length and you go and look up the 100-year max wind speed for your location (just to be conservative) in the handbooks. You perform a finite element analysis of the antenna with the max wind load assumed and your analysis tells you everything looks ok – the maximum stresses due to bending are well below any sort of yield or fracture stress for the material. You tell your boss everything looks good and drive home through a thunderstorm with a great feeling of another job well done. Upon returning to work the next morning, you immediately have a sinking feeling in your stomach when you find a broken antenna on your desk with a note from your boss saying, "This was one of the prototypes on the truck in the parking lot." Uh-oh... What went wrong? "The Challenge" is presented for a little fun. If you have a teaser that you'd like to submit, please e-mail the question and answer to: cchestara@globalspec.com. (The more difficult the challenge, the better!) |
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Spotlight On . . .
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Free Vibration Solutions SourceBook from IOtech For over 10 years, IOtech has offered the widest variety of test solutions for making vibration measurements for portable and stand-alone applications. We have just completed a compilation of actual customer-developed applications into a new publication, the Vibration Solutions SourceBook. There are a total of 17 product applications from Hearing Implant Research to Remote Turbine Monitoring. Request your copy today! Click here for more information about IOtech's products. |
Maple Systems Introduces New Family of Affordable Touchscreen HMIs Maple Systems introduces the Silver Series – powerful and affordable new touchscreen HMIs. With features like Ethernet, compact flash, 256-color graphics, three types of object movement and animation, multiple language support and macros, the Silver Series is designed to meet the needs of today's automation. Contact Maple Systems at 425.745.3229 or via e-mail for more information. |
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New Products and Services on GlobalSpec
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These
SpecSearchable categories were recently added to GlobalSpec. |
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New Suppliers on GlobalSpec
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Listed
below are the SpecSearchable manufacturers recently added to GlobalSpec, including
links to their online catalogs. |
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| ASCO Canon U.S.A., Inc. Durable Products, Inc. F.W. Gartner Thermal Spraying Co. Horner APG IAC Industries, Inc. IDM Instruments J.W. Industries, Inc. Lambda Americas Lapmaster International Marlin Steel Wire Products LLC |
Measurement Computing |
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Last
Edition's Survey Winner Is...
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"The
way to get started is to quit talking and begin doing."
Walt Disney