Recovering Industrial Lubricants How to Use a Centrifuge Disc Stack centrifuge

What uses do industrial lubricants serve?

All kinds of industries use lubricants, including oil and grease. From lubricating industrial hydraulics, lubricating dies in aluminum wire drawing, lubricating bearings in steel mills, and several other applications of a similar nature.

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Types and causes of contamination in lubricating oil

Particle contamination and water contamination are the two categories of lubricant contaminants. Tiny particles (less than 5µ) found in lubricating oil are caused by hard hydrocarbons, metal wear, dust from the air, and combustion residue.

Water becomes contaminated due to seepage and condensation. These impurities shorten the life of lubricants and increase the expense of preventive and corrective maintenance.

Expenses associated with contaminated lubricant

In general, three different kinds of costs result from lubricant contamination.

1. Problems with product quality and early equipment failure.

The chart that follows, for instance, illustrates how lubricant contamination affects bearing life.

2. High expenses for disposal and lubricant.

3. Lubricant disposal’s environmental cost.

Thus, it is desirable, feasible, and potentially very cost-effective to reuse these lubricants. Disc-stack centrifuges are the preferred equipment for recovering industrial lubricants and are widely utilized.

A succinct explanation of centrifugal separation

Centrifugal separation is the process of using centrifugal force to accelerate sedimentation. The natural force of gravity is multiplied thousands of times by a centrifugal separator. It makes use of centrifugal force, which the fluid’s rotation produces.

What is a disc stack centrifuge?

One type of centrifugal separator is the disc stack centrifuge. A centrifugal separator’s bowl is supplemented with a disc stack, or set of conical plates. The ‘disc stack’ addition creates additional settling area. The process of separation proceeds tenfold faster thanks to this increased surface area.

What is the operation of a disc stack centrifuge?

Disc stack centrifuges simultaneously separate one or more liquids and solids. There is just one ongoing process here. To separate the phases, the centrifuge generates incredibly high centrifugal forces.

When this force is applied, the denser solids travel outward in the direction of the rotating bowl wall. Inner layers are concentric, formed by the less dense liquid phases.

The separated solids gather at the edge of the bowl and are either manually or self-expelled.

In the direction of the bowl center, the separated liquid phase(s) travel radially inward. Through the bowl top’s outlet openings, the liquid(s) overflow.

The overflow of the clarified liquid phase (or phases) in the outlet area above the bowl, near the rotating axis. Separate outlet chambers allow the two liquids to leave the bowl via different pathways when there are two liquids present.

To sum up, a disc stack centrifuge continuously extracts solids and water from the lubricating oil. This implies that output will continue even if there is a significant water leak into the lubricating system. To restore oil properties, the centrifuge will maintain the water content within predetermined limits. Furthermore, it eliminates the water alone—the additives are left behind.

Steel Rolling Mill Case Study

The Issue

Steel billets are turned into steel wire at a rolling mill in the Midwest. By wire drawing, the mill turns two-ton steel billets into wire. The least amount of downtime is crucial because this is a round-the-clock operation.

Lubricating oil is used in the gearboxes and rollers. Splashes of cooling water on gearboxes cause the oil to seep into it. Lubricating oil contamination with water had turned into a production bottleneck. Gearboxes and bearings prematurely fail as a result of contaminated oil. Equipment failure-related production losses can mount up quickly.

Every year, lubricating oil that should have lasted three to five years had to be changed! Their annual operating budget had to be increased by an additional $100,000 due to the replacement of over 5,000 gallons of oil.

Because of the low operating temperature, the water in lubricants does not evaporate. It is crucial to eliminate the water using alternative techniques like a coalescer or a disc stack centrifuge.

The Solution

An extremely fast disc-stack centrifuge turned out to be the solution. All free water and particle pollutants are separated by the centrifuge. Additionally, it is capable of separating large amounts of water (>50%) from oil. To maintain an acceptable level of oil contamination, the centrifuge runs continuously.

The centrifuge’s’self-cleaning’ design enables completely automated operation. This reduces the requirement for a centrifuge operator to work full-time.

The Outcome

Adding the centrifuge had several advantages. Now, the interval between lubricant oil replacements is more than three years. That means yearly replacement oil cost savings of over $100,000. Within the first year, these savings alone covered the cost of the centrifuge.

The customer also benefited from the removal of unscheduled downtime. Higher production efficiencies were the result throughout the plant.