Pillowblock load cell
Like ABB's larger load cells based on Pressductor™ electromagnetic transducer technology, Mini Series PillowBlock Load Cells rely on electromagnetic changes in the transducer, not on physical movement, to sense fluctuation in web tension. Result: increased reliability and durability, improved repeatability, less drift, and extended measurement range. Three Mini Series models measure 0.02 to 20kN (2 to 1,500 lb), and are targeted at the converting industry.
Load-cell operation, based on a metallurgical phenomenon where mechanical forces alter the capacity of some steels to convey magnetic flux, relies on two perpendicular windings of copper wire around a steel core that combine to provide the measurement signal.
A magnetic field is created in one of the windings, sized so there is no magnetic coupling between them. When the transducer is subjected to a force, the magnetic field pattern changes. A portion of the field couples with the second winding and induces an ac voltage proportional to the force.
ABB Industrial Systems Inc., 100 Madison Corporate Park,Rte. 6, Brewster, NY 10509; (914) 278-6818.
| Innovations in metallurgy, production technology, and load-cell design let ABB adapt its Pressductor technology for use in a comparatively small and inexpensive device for a broad array of converting, plastic film, and web processing applications. |
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| Unlike strain gauges and load-cells that require physical movement (compression, stretching or bending) for signal generation, Pressductor signals result from mechanical forces that alter an electromagnetic field. |
Opacity mode sensing
Two solid-plastic light guides form the basis of these inexpensive and interchangeable optical blocks. Their tips, cut and polished on a 45-degree angle, direct light across a gap from one guide to the other, enabling a variety of applications—from registration mark sensing and envelope contents verification to liquid level detection.
Attached with two screws to any Tri-Tronics photoelectric sensor, Gap ProbeTM optical blocks reduce the inventory burden of replacement parts and eliminate the need for discarding a complete sensor in case of damage to the optical block.
Tri-Tronics Company Inc., Box 25135, Tampa, FL 33622; Tel: (813) 886-4000.
| Most envelopes are not opaque, but translucent. Some light will pass through. If one or more sheets of paper are inside the envelope, the sensor can be adjusted to resolve an empty envelope. |
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Gap ProbeTM optical blocks convert any Tri-Tronics photoelectric sensor into a low-cost ‘slot’ or ‘fork’ sensor. |
| When the tips of the two light guides touch the meniscus of water, their 45-degree angled surfaces no longer reflect light across the gap. Instead, light travels straight out the end of the guide. The sensor can therefore be adjusted to detect the presence of almost any liquid. |
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