Correct equipment selection and application saved an aluminum producer $36,000.
by Mike Winkler (Motion Industries)
March 6, 2015

A good distributor's specialist looks beyond the symptom to define the problem's root cause instead of offering a quick fix. When looking out for the user's welfare, the specialist's focus should not be on selling but on troubleshooting and providing corrective measures. This approach will bring value to the plant floor by reducing their overall cost of ownership, suggesting methods or designs to improve efficiency and helping to ensure productivity.

How One Plant Saved Thousands in Repairs & Replacement

Correct equipment selection and application can provide an efficient and reliable pump and system. In the following case, a distributor's pump specialist assisted a user, a major producer of extruded aluminum, with a solution that led to $36,000 in savings.

The Root of the Problem

The aluminum producer needed to solve the problem of shortened life of their 6x6 vertical pumps. The pumps, used for an acid wash on their paint line, were lasting only six to eight months. After that, volute and impeller failure would occur. A quick observation showed the problem. The pump was not mounted deep enough in the tank to keep the liquid from vortexing and causing cavitation to the pump.

Because of this, the 1 percent sulfuric acid the user was pumping was at a velocity far too high for the depth of the bell housing of the pump. The fluid should have been moving at about 3.25 feet per second but was moving more than four times as fast at 14.76 feet per second. The lower velocity would prevent the pump from vortexing at the pump's immersion depth. Immersing the pump lower would have stopped the vortex and prevented inevitable failure immediately.

Lowering the pump, however, posed a problem. At the current velocity, the pump would need to be immersed to 13.5 feet. The tank was only 44 inches deep.

Luckily, immersion depth was not the only way to correct the problem and prevent constant maintenance issues. The pump was also incorrectly mounted, which was quickly corrected.

The distributor's pump specialist determined a simple fix by placing a stainless steel plate above the bell housing of the pump to act as a vortex breaker. This plate would correct both the vortexing and the entire system. The specialist calculated the required size of the plate, the user made it to his specifications, and the plate was immediately attached.

A Long-Lasting Solution

At one time, this plant's $10,000 pumps needed repairs costing at least $2,000 every 30 to 45 days, with a complete replacement of the pump every six to eight months costing $10,000 to $12,000. Since the problem was corrected with the distributor's help, the pump has operated for two years without further maintenance or repairs—resulting in approximately $36,000 in savings since implementation.

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