When several pairs of rollers at a steel mill were not flattening sheets of steel properly, engineers used data from telemetered strain gauges supplied by Binsfeld Engineering Inc. in Maple City, Mich., to help pinpoint the cause of the problem.

To flatten the sheets of steel properly, all rollers have to operate at the same speed. Engineers decided that measuring torque on each roller would provide an accurate picture of how motors for the rollers were working. Determining torque on rotating machinery can be difficult, however. The engineers found that transmitting torque data from a strain gauge could overcome the problems with traditional methods such as slip rings and in-line torque sensors, which can be cumbersome and costly.

The telemetry transmitter straps on the shaft rather than slipping over it, so no machine disassembly is required. Also eliminated are the problems associated with trying to send a 1-millivolt signal across a mechanical interface that becomes noisy from dirt and wear. Factors such as torque, strain, temperature, and pressure can be relayed from sensors on the machinery.

Bonding a torsion-sensitive strain gauge to the existing shaft eliminates the cut-and-fit requirements of the in-line torque sensor. Commercially available strain gauges are simple to install and mount instantly with adhesive. In most applications, only a single stamp gauge is required, and alignment is accomplished visually.

The strain gauges in the steel mill revealed that two sets of rollers were operating much more slowly than the first set, impeding steel throughput. The mill operators chose a quick and easy solution for the short term: They turned off one or both of the motors on the slower rollers so the steel could pass through more easily.

Misaligned rotors reduce turbine output and increase the risk of breakdown. To check alignment, several ABB SSA gauges are mounted (permanently or temporarily) to the turbine shaft near the couplings. The turbine is rotated slowly for two revolutions, and signals from the strain gauges are sent to a data logger. If realignment is needed, maintenance personnel use the SSA to check the rotor alignment before and after adjusting it to ensure improvement.

Other methods of alignment checks traditionally involve measuring the angular deviation of the rotor-shaft couplings. Maintenance crews must take several days to dismantle the shaft couplings and insert measurement fittings, then reassemble the couplings.

The SSA system made its American debut at the 680-megawatt steam-turbine group at the Nebraska Public Power District's Gerald Gentleman Station in Sutherland in April. Plant management was able to save a minimum of five 12-hour shifts during full shaft outage, according to John Cizek, senior staff engineer at Gerald Gentleman. He also credited the SSA with reducing human error.

ABB foresees greater opportunity for the SSA system in the United States as deregulation forces utilities to improve plant output and availability.

At the heart of the McCrometer flowmeter is a V-shaped cone that fully mixes, conditions, and profiles the flow before measuring pressure fields that represent the rate. The V-Cone generates low-amplitude pressure fields, as opposed to the high-amplitude fields of venturi flowmeters, reducing the possibility of error. Low amplitude translates into a signal from the V-Cone that is highly stable.

The V-shaped cone in the McCrometer flowmeter eliminates the need for additional flow conditioners, permitting installation on offshore oil rigs

Conditioning in the meter provides readings within 0.5-percent accuracy and 0.1-percent repeatability. The V-Cones can measure flow ranges of more than 15:1, and can accommodate pipe diameters ranging from 1/2 inch to more than 120 inches.

Maersk Oil in Copenhagen, Denmark, will be installing 25 V-Cone flowmeters on three North Sea oil projects through this October. The Maersk V-Cones will be used for a variety of flow-measurement applications--including water, natural-gas, and compressor control--on piping systems 3 to 24 inches in diameter.

In addition to offshore platforms, the V-Cones are used in mining, chemical processing, pulp and paper, and wastewater-treatment plants.

The DCI System Six was specifically designed to improve batch and continuous processes. The system's single X-Window Display Center screen displays up to four full-function, freely assignable operator windows. Each screen contains its own dedicated minialarm and configuration windows. Controlware II, written by Bailey, configures an entire process control system with preprogrammed modules--which serve as input/output databases, process controllers, sequential logic controllers, or parts of customized control strategies--by graphically linking these modules to create a pictorial view of the logic.

Under the terms of S.C. 749, one of the city's most recent projects, Bailey engineers will supply the DCI System Six control systems, magnetic flowmeters, flow tubes, transmitters, and analyzers to upgrade the Back River Plant's activated-sludge process. Improving the airflow to the reactor tanks will reduce costs and raise plant effluent quality.

Another Baltimore project, S.C. 720, involves installing another section of the DCI System Six control system to upgrade a plant's central metering by August 1998. This project is expected to reduce costs at locations in the plant including the grit tanks, primary clairifiers, high-rate digesters, egg-shaped digesters, sludge-control facilities, vacuum filters, and polymer system.

Conventional fuel gauges are made of thick-film cermet materials on a ceramic substrate. While generally reliable, these gauges are still prone to degradation once a vehicle has been in service for more than 150,000 miles, a level trucks can easily go beyond with current technology.

To create a fuel gauge that is less susceptible to conventional problems, Spectrol Electronics in Ontario, Calif., has developed a technology known as silver-in-glass that reportedly improves the service life of fuel-level sensors by a factor of 25.

Conventional thick-film technology places a cermet conductor directly onto a ceramic surface. This conductor can be worn away by the contact mechanism, after which the contact rides on the abrasive substrate. The silver-in-glass contacting encoder places the conductor on a smooth glass layer. During the thermal processing of the conductor, the silver material diffuses into the glass surface so that only a small portion is exposed to the wiping mechanism. The resulting product consists of a smooth, partially submerged conductive wiping bar surrounded by a uniform glass surface. The conductor particles are embedded in--and surrounded by--glass, making it nearly impossible to dislodge the conductor material by ablation from the moving contact.

The step-height differential between the conductor and insulator surface for silver-in-glass mechanisms is generally 5 to 8 microns; designs that use a composite board with copper-foil etching have a 25- to 35-micron differential. This improvement not only increases wear life and virtually eliminates electrical noise problems but also negates switching-accuracy failures by enhancing the dimensional stability of the entire material system. Several auto manufacturers are evaluating a fuel-level sensor that uses this technology.

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