Bearing maintenance tools enhance sustainability with rotating equipment

Reliability goes green for rotating equipment: Four innovations can help you meet sustainability goals.

By Paul Michalicka, SKF USA Inc.

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Energy-conserving rotating equipment components and advanced maintenance technologies can help an enterprise meet its environmental objectives and achieve greater overall sustainability. Benefits include more efficient use of energy and raw materials, reduced waste in manufacturing processes, minimized environmental assaults, and reduced carbon and other emissions.

Plant managers, maintenance professionals and others charged with improving sustainability have a greater range of options available than ever before. These include rolling bearings and bearing units that are optimized for low-friction, energy-conserving operation, highly accurate lubricant-dispensing systems and laser-equipped alignment instruments.

Ultra-efficient rotating components

Shaft bearings directly affect a plant’s productivity, energy use and overall sustainability. As more attention has focused on sustainability during the past decade, technical innovations result in new generations of highly efficient rolling bearings.

One example is energy-efficient deep-groove ball bearings designed for light- and medium-load applications in electric motors, pumps, conveyors and fans. Equipped with an optimized internal geometry, these bearings consume 30% to 50% less energy than standard deep-groove ball bearings in similar applications.

Their low-friction performance was confirmed by tests conducted on a 3-kW electric motor. The free running time of various bearings was measured after power to the motor was switched off. The energy-efficient bearings ran 50% longer after power shutdown than standard deep groove ball bearings.

Energy-efficient deep-groove ball bearings are shielded on both sides and equipped with a snap-type cage made of a temperature-resistant glass fiber-reinforced polymer. The bearings are lubricated with a low-noise, low-friction grease.

The energy-efficient bearings ran 50% longer after power shutdown than standard deep groove ball bearings.

– Paul Michalicka, SKF USA Inc.

In addition, you can upgrade to lubricated-for-life bearing units designed for food-industry and related applications. These bearing units reduce grease consumption during the bearing’s lifecycle and prevent grease from entering the waste stream. In one case, a company in the northwestern United States replaced cast-iron pillow blocks with lubed-for-life bearing units on its multi-lane sorting machinery used for apple processing. The conventional pillow blocks had sustained rusting and lubricant washout and had a life expectancy of only three months. The new bearings featured corrosion-resistant composite housings.

After the test period proved successful, the company specified the lubed-for-life composite units as drop-in replacements for the conventional cast-iron units. The composite units feature specially coated insert bearings and stainless steel sealing components. They withstand high-pressure washdowns without purging grease and are lubricated with USDA-approved food-grade grease. Equipped with these bearing units, the upgraded apple sorters have operated for a full year without requiring any bearing-related service.

Studies estimate that, in a typical application, these lubed-for-life units save more than 100 oz. of grease per unit annually. Depending on the number of units, in a single year a plant can keep many thousands of ounces of grease out of the environment.

Waste-reducing lube dispensers

Most bearings require periodic relubrication. For reasons of productivity and sustainability, it’s important to follow correct lubrication practices and avoid underlubricating or overlubricating. Underlubrication can cause metal-to-metal contact between bearing components and eventual bearing failure. Overlubrication causes churning, which results in higher operating temperatures and lubricant degradation. On the macro level, excessive lubrication throughout a plant increases lubricant consumption and waste.

Automatic dispensing systems can keep lubricant usage under control. They deliver a steady flow of lubricant directly to machine points, supplying just the right amount of lubricant needed. One popular type of single-point lubricator is a self-contained, electromechanically driven unit consisting of a battery-operated motor and a lubricant canister. The canister can hold 250 ml of either grease or oil. When activated, the motor drives a piston that dispenses the lubricant at the preset user-selected rate. This single-point lubricator can be mounted remotely to lubricate bearings in areas with high temperatures or excessive vibration.

Higher-capacity, multi-point lubricators are intended for heavy-duty applications such as hot gas fans and calendar rolls in paper mills. These systems distribute grease or oil from a central canister through as many as eight feed lines.

Manual relubing is still the norm in many applications. It can be difficult, however, to measure the amount of grease injected using manual methods. Grease meters can provide a sustainable solution. They can measure grease quantities by volume or weight accurately and display the amounts on built-in screens. They’re usually compatible with a variety of grease guns and pumps.

Green lubricants

Lubricant formulation represents another sustainability issue. A growing number of biodegradable “green” greases are available for applications if environmental contamination is a concern. One such lubricant, a low-toxicity, synthetic ester oil-based grease, is designed for water treatment, irrigation, agricultural, forestry, construction, mining and other such applications.

The grease, intended for use in ball and roller bearings and spherical plain bearings, complies with government regulations on toxicity and biodegradability. It exhibits good performance in low-temperature startups and has superior corrosion-inhibiting properties.

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