How one company accomplished a complete overhaul of four pumps at water treatment facility.
by Loren Nauss
November 27, 2017

Nearly every business, industry, municipality, school and home has and uses pumps. They pump everything from drinking water and wastewater in cities and towns to heavy aggregate solutions in mines, quarries, power plants, and in oil and gas fields. As common as pumps are, when normally functioning they are often overlooked until they need attention.

This usually shows itself in a few ways:

  • increasing bearing noise
  • sudden increase in vibration
  • pumping output dropping 25 to 50 percent, which shows up as an increase on the electric bill

For discussion here, a homeowner takes a walk outside early one Saturday morning and hears his 17-year-old pool pump screaming for attention. Then, after a quick analysis and $150, the homeowner picks up the new motor, swaps it out and the summer fun continues.

Now, let’s scale this up to industrial application proportion and to situations many of the engineers, managers and maintenance professionals either have run into or likely will in the future. Situations like this happen in the industrial workplace all the time requiring analysis of the situation, investment in repairs or new equipment and potential for very high downtime costs. The untimely failure of a single piece of equipment like a pump can lead to astronomical costs, and they can add up in a hurry.

failure to repair pumpImage 1. Failure to repair a pump can lead to more expensive problems. (Images courtesy of Henkel)

There are many types of pumps in an array of industries that, at some point or another, require service and maintenance to optimize their functionality. At one point in time, the only cost that seemed important was the purchase and installation price of the pump. Today folks realize that purchase price is often only a small part of the overall cost of a pump, and other factors like warranty, installation/rigging, operating parameters, plant/facility alteration requirements, pump service and repair, and pump efficiency all factor into the total cost of ownership. In the pool pump, the decision was pretty simple with a low-cost motor replacement solution.

In an industrial application, a pump issue decision is more complicated, and the associated costs can run into tens of thousands of dollars and more.

Examining Cost to Repair Pumps vs. Cost to Replace

Recently, the regional Water Pollution Control Authority in Waterbury, Connecticut, reached the point where major mid-life service was required on all four of their Allis Chalmers Model NSYV 250 Influent pumps. The pumps had been in service for 19 years and were showing signs that major service would be required in the near future.

The City of Waterbury employed the professional engineering services of Tighe and Bond to develop proposals and assist in managing the project for the sequential overhaul of the pumps, motors, drive shafts and discharge check valves over a 12-month span.

The technical and price evaluation resulted in the project award to New England Pump and Valve Company (NEPV).

purchase price pumpImage 2. Purchase price is only a small component of maintaining the life of a pump.

Many factors are taken into consideration when it comes to performing a job of this type and there are typically two perspectives that weigh heaviest. The pump owner is usually looking at the following factors in a service provider:
knowledge and experience

  • the provider’s resources (technical, financial, and workforce) to complete the work as proposed
  • the relationships within complementary industries required in order to complete
  • the work
  • their professional reputation

Technically the pump owner is weighing the costs to repair versus to replace. Some of these considerations include: new versus overhaul costs, new pump system modification costs, parts obsolescence and original equipment manufacturer (OEM) support, and energy efficiency gains.

Sometimes, a pump housing or casing may be so unique that refurbishment and repair is the only way to go.

Even though the technology exists today, years after the original installation a different type of pump might perform the same function in a much simpler way. Lastly, often the equipment required to rebuild some larger pumps is not found in today’s standard machine shops.

Studies of large pump efficiency have become popular due to the potential for significant cost savings.

large pump efficiencyImage 3. Studies of large pump efficiency have become popular due to the potential for significant cost savings.

The City of Waterbury recognized the potential to reduce total ownership costs while completing this major overhaul project and partnered with the local electrical provider Eversource Energy to reduce energy consumption. The project is comprehensive and rigorous in approach to ensure the customer achieved all of their objectives including the following major project components.

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