What works

In recent years, many companies have come to rely on predictive maintenance (PdM) as a means of improving maintenance efficiency and minimizing downtime. DaimlerChrysler took that approach one step further by applying it to its new machinery at a new facility, saving the company $112,000.

"During the launch period of this new plant, we requested evaluations via vibration analysis and IR analysis as one of our criteria before we signed off on the equipment and took ownership," says Terry Kulczak, maintenance advisor for DaimlerChrysler's Toledo North assembly plant, "We had already settled on the DLI Engineering system for this task because we had good success with it at our Durango plant in Newark, Del."

For the Toledo North plant, Kulczak's team used the Bremerton, Wash.-based DLI Engineering's PdM system to evaluate more than 600 pieces of equipment, ranging from regenerative thermal oxidizer motors to water pumps, cooling fans and gearboxes. The system identified 106 pieces of equipment needing adjustment or new parts. Kulczak estimated that the maintenance costs to repair these defects would range from a minimum of $31,000 to a maximum of $112,000, not including production downtime losses.

Instead, the flawed pieces of equipment were replaced,under warranty. "Using the DLI Engineering software, we found some machines weren't up to spec. Some had bad bearings, alignment problems and improperly sized shims, which led to excessive vibration. These had to be changed out, and it was done under warranty. For us, PdM software proved to be a very useful tool," says Kulczak.

DaimlerChrysler used predictive maintenance to evaluate more than 600 new pieces of equipment at its new Toledo North plant.

The DLI Engineering PdM system used by DaimlerChrysler represents a new generation of maintenance tool and is a far cry from the run-to-fail maintenance schedules plant engineers used previously. Dean Lofall, product development manager for DLI Engineering, recalls, "When we started out doing machine condition analysis for the U.S. Navy in 1966, vibration work was manual. You'd have a group of engineers go on the ship for 10 days and gather the measurements via analog instrumentation tap recordings. The technicians would play recordings through a processor to produce a five-foot high stack of graphics. For the next three weeks, the engineers would go through the data, manually categorizing the machinery and making specific repair recommendations."

Technology has made gigantic advances since then. New field instrumentation measures torsional vibration, torque and horsepower, motor current, structural vibration, shaft alignment and acoustics with ever-increasing accuracy and fidelity. Equally important, a focus on portability has placed condition monitoring into the hands of production floor personnel. "With today's versatile and portable data collection systems, we're basically doing EKGs on machines," explains Lofall. "Just like when you go to the doctor, an EKG will detect problems early. Similarly, machines give off precursors, or early indicators, of future problems. Detecting incipient faults, whether on the production floor or at a distant location, is what these tools are about."

In addition to data collection and analysis, a PdM system provides easy access to information. "Connectivity is a big part of making PdM pay for itself," says Lofall. "It doesn't do any good to have the information unless it gets to the right people."

When a Georgia-based manufacturer of paper products expanded its production capacity and physical plant, it came under more stringent emission-control standards for its two multi-fuel boilers. The boilers use a diverse combination of fuels that include wood/bark, sludge, coal and oil to produce approximately 500,000 lbs of steam per hr. To meet current and future emission control standards, the paper manufacturer selected a turnkey Venturi system by Parsippany, N.J.-based AirPol, Inc., which can be designed for practically any particulate emission level and upgraded to meet future requirements easily.

The Venturi scrubbers replaced two existing AirPol scrubbers originally installed in 1974. The previous scrubber system had provided good service until the boiler capacity requirements increased during the plant's expansion in the mid-1990s. The large increase in gas volume from the boilers caused excessive particulate emissions and increased stack opacity levels. Ironically, the most annoying effect for mill personnel was the dirty droplets "raining" from the stacks.

To meet current and future emission control standards, a paper manufacturing plant selected a turnkey system by AirPol, Inc.

In selecting the AirPol system, the paper manufacturer established clear requirements. It had to meet the gas volume per boiler requirement of approximately 450,000 ACFM at 390°F, with a maximum particulate loading of 2,680 pounds/hr. It had to handle process gas volume fluctuations for the two boilers, which operated 24/7. It also had to be adaptable to meet future control standards. And, it had to accommodate a strict limitation for liquid discharge from the stacks.

AirPol's system incorporated two gas-leaning systems. Each Venturi is equipped with a double-bladed, large-diameter, adjustable-throat scrubber, which ensures constant pressure drop to accommodate variations in flue gas volume. Also included is a cyclone separator, exhaust stack and recycle tank. The project included structural support towers, stairways, ductwork, instrumentation, demolition of existing equipment and installation, commissioning and startup.