MRO Magazine

Feature

Two-Step Process Extends Life of Gear Drives

Picture this -- a 600-hp extruder drive pushing wet clay through a moulding die in a brick plant. It's a tough job! The heavy loading takes its toll on the gearing, and the need to resist airborne con...


Picture this — a 600-hp extruder drive pushing wet clay through a moulding die in a brick plant. It’s a tough job! The heavy loading takes its toll on the gearing, and the need to resist airborne contaminants poses an additional challenge.

Gear drive failures are primarily due to friction and lack of lubrication. For example, fatigue breakage can be related to jamming of the drive, but is most often the result of heavy loading. The metal-to-metal contact on gear faces, which occurs when traditional oils are squeezed out, causes heavy friction and fatigue. This often results in teeth being torn loose.

Pitting and spalling occur when severe rolling and abrasion on gear faces causes the loss of oil film, and metal-to-metal contact generates high heat. These events produce wear debris that accelerates the failure.

A highly neglected issue in industry is lubricant filtration, which makes it a contributing factor in most gear drive failures. Oil analysis detects the need for filtration, while proper filtration not only solves the problem of lubricant contamination, but also prolongs equipment life.

Dedicated depth filtration is an effective approach for large drives, while portable side-stream depth filtration is an appropriate solution for mid-size drives.

Changing oil on small drives allows the old oil to be removed, analyzed, filtered and possibly reused, providing a cost-effective maintenance technique. The use of rated air breathers is also an important step for proper filtration, as they prevent airborne contaminants from entering the clean oil reservoir.

Two-step process

A recently developed two-step process for protecting industrial gear drives not only reduces energy consumption and wear, but also addresses the issue of airborne contaminant ingress. This innovative, synergistic process, which has already been adopted by several companies, resolves difficult failure issues — with the added incentive of an environmental payback.

The first step for any large drive, such the one in the brick plant, is to ensure it has an up-to-date oil filtration system in place. Case studies by Lubrigard, a division of Wear Check Canada, have proven that the installation of a dedicated filtration system assures low cleanliness codes will be met. In one example, the installation of this technology extended the repair cycle on this extruder drive from 14 months to 36 months.

The second step in the process is the use of a Fastex surface modifier. This process initially cleans all internal parts of the drive by removing varnish and sludge. It then deposits a sacrificial, sub-micron coating on all metal surfaces, which decreases friction between the rolling and sliding surfaces. The result is a dramatic reduction in energy and wear. At subsequent oil changes, Fastex blended oil can be used for ease of maintenance.

In the example of the aforementioned brick plant extruder drive, which traditionally drew 500 amps, the result of applying these two steps was a 50-amp reduction in power consumption, which translated into a cost saving of $15,176 per year.

Also noted was an estimated 80% reduction in wear debris, as well as a marked reduction in vibration and noise. The gear drive manufacturer’s representative was amazed at the difference in both levels, which were much lower than traditionally experienced.

The correct filtration methods vastly improved the life of the drive and the addition of the Fastex surface modifier significantly lowered the wear debris, noise and vibration by reducing friction for additional life extension.

Astounding synergy

The synergy of using proper filtration and a friction modifier is astounding. Neither traditional oils nor filtration alone can achieve these results. The cleanliness codes on equipment using this two-step process are greatly improved and this drive has attained an incredible ISO rating of 17/15/12, which is much better then the acceptable ISO codes of 20/18/15.

At the time of the manufacturer’s two-year inspection of the extruder drive unit, it was running so smoothly that a scheduled repair was unnecessary, resulting in a $50,000 saving for the company.

The energy reduction of 50 amps or 216,810 kWh on this one drive equates to a reduction of 150 metric tons of CO2, or the equivalent of 23 cars removed from the road per year. Just imagine the impact on the carbon footprint for an entire plant.

Case studies have shown that the combined technology of the Fastex surface modifier and Lubrigard filtration upgrades produce an ROI (return on investment) of less then six months. The two-step process not only extends the drive life while reducing energy costs, but provides an easily implemented solution to environmental concerns. The effective reduction of CO2 emissions is also a potential revenue stream through the sale of energy credits.

Employing this process makes it possible to participate in saving the environment through energy reduction while reducing maintenance costs and downtime.

Gary Latham is business manager, reliability solutions, for Canadian Bearings Ltd., Mississauga, Ont., the industrial distributor that devised this two-step solution.