PLANT print issue: Raise your green profile
Upgrading practices saves energy, cuts waste and does a better job of meeting environmental standards.
Many manufacturers will observe progress made towards improving sustainability varies between their plants and – more surprisingly – across departments and operations within the same facility.
Take the case of rotating equipment operation and maintenance, a critical part of most industrial activities. Inefficient maintenance practices and outdated tools produce excessive waste and fritter away energy resources, offsetting gains made in other areas.
Here are five quick improvements that will save you money:
1. Use energy-efficient mounting methods. Some older methods for mounting mid-size and larger components are proven energy drains, yet they’re still widely used. Open flames not only waste energy, they easily damage bearing components during heating. Oil baths are a safer method, but they’re hard to control and take too much time to reach a desired temperature.
Advanced installation technologies such as modern induction heaters generally have built-in energy saving features and simplify mounting.
2. Upgrade shaft/belt alignment practices. Even tiny amounts of misalignment in coupled machines decrease bearing life and waste energy. For every additional degree of vertical or horizontal misalignment, energy use rises exponentially.
Plants relying on straightedges and visual inspection to align coupled shafts should be aware that this method is not especially accurate and permits small amounts of misalignment. New systems equipped with laser sighting offer a better option.
In a recent case, a European beer producer experienced rising energy costs because 75 pumps were affected by misalignment. To correct the problem, the company acquired two shaft alignment systems with built-in laser sighting. The systems each consisted of a hand-held display unit and dual measuring units designed for positioning a few feet apart on opposing shafts. During operation, each measuring unit projects a laser line toward the opposing unit’s detector. While viewing “live” dimensions on the display unit’s screen, the operator adjusts the shafts until they are correctly aligned. The systems required little training and included a “soft foot” function that verifies rotating machines are standing evenly on all feet.
The new alignment method lowered energy consumption by nearly $40,000 annually, and total investment in new equipment was recouped in about four months.
Belt alignment systems have been developed for pulley- and belt-driven applications. The most accurate systems align the grooves of pulleys instead of their faces, enabling alignment of pulleys with unequal widths or dissimilar faces.
3. Use low-torque greases. New-generation low-torque greases developed for use with high-efficiency, energy conserving bearings minimize friction-related energy loss. One new grease combines fully synthetic base oil with a lithium soap thickener to promote quiet running and oxidation stability.
Biodegradable greases are also available for applications where contamination is a concern, and they reduce lube disposal costs.
4. Remove human error from lubricant delivery. Maintenance departments sometimes overlubricate rotating machines believing that more lubricant is always better. But overlubrication causes churning, which results in higher operating temperatures, energy loss and eventual bearing failure. It also increases grease and oil disposal costs.
The best practice from a sustainability and operational standpoint is to use the minimum lubricant necessary.
Using automatic lubricators are an effective way to eliminate human error and conserve lubricant, as a food manufacturer that installed single-point lubricators on a number of production lines discovered.
The lubricators use electromechanical force and a piston mechanism to deliver a consistent flow of grease directly to machine points. They fill to 250 millilitres of grease and operate for weeks without replenishment.
The lubricators gauged flow precisely, reducing consumption by more than $120,000 over a year, and the plant eliminated more than 62,000 manual lubrication tasks, cutting labour costs dramatically.
Multipoint lubricators also reduce labour requirements. They dispense grease or oil from a central canister through feed lines to as many as 20 lubrication points.
5. Monitor energy losses with advanced instruments. Newly developed monitoring instruments reveal energy losses and machine problems that might otherwise go undetected. Helpful technologies include ultrasonic detection, thermography and electrical discharge monitoring.
Ultrasonic instruments identify leaks in heat exchangers, boilers and condensers by detecting the high-frequency sounds made by leak turbulence. They convert the sounds to audible signals, alerting operators to leak locations. Hand-held thermal cameras detect energy in the spectrum’s infrared band to identify “hot spots” in all types of operating machinery. Portable electrical discharge detectors identify erosion in electric motors, preventing bearing damage and they conserve energy.
Assessing the impact of your plant’s maintenance practices on energy use, production efficiency, waste and disposal costs, then applying these practices will pay off with savings while improving sustainability and compliance with environmental standards.
Paul Michalicka is North American area sales manager for maintenance products, SKF USA, based in Toronto. E-mail Paul.Michalicka@skf.com or phone (416) 299-2894.
This article appears in the Sept. 2013 edition of PLANT.
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