July 2018 - Decatur Industrial Electric

Decatur Industrial Electric Saves Steel Customer through our Start-Up Process

One of the most effective strategies for avoiding unplanned interruptions is correct installation at the beginning of the equipment’s life. If installation and commissioning is carried out carefully using the correct procedures, it is an investment in the machine´s serviceability and reliability for its entire service life.

In this situation, a customer was looking to install vertical pump motors but they were having issues with the process. Decatur Industrial was engaged and proposed putting together an “install kit” for each of their groups of vertical pump applications. After reviewing the equipment, our experts came up with the kit components.

Each kit has the following to discreetly address the mechanics needs for installation.

(1) HEAD SHAFT

(1) HEAD SHAFT NUT

(1) LINE SHAFT COUPLING

(1) GIB KEY

(1) V-RING

We added the V-Ring as a failsafe, as it is non-standard and new for the application. It will sit immediately below the steady-bushing once it has been locked in place. This prevents water from being forced between the shaft and the steady bushing bore.

By engaging Decatur Industrial Electric these kits allowed for proper installation and commissioning; and most likely a long life for these vertical pump motors.

Next steps: Vibration analysis, oil sampling, and electrical testing to monitor the motors health.

Learn warning signs of needed repairs and avoid common mistakes.

Vertical turbine pumps (VTPs) are workhorses in the petrochemical, power generation and manufacturing industries, and prolific in municipal water applications that handle the primary intake load. The ability to develop high head with multiple impeller bowls—coupled with the ubiquity of standard vertical motors that can support heavy pump shaft loads—makes VTPs a good choice. Although these machines are ruggedly built, abrasive sediments in the pumpage take a toll, particularly on line shaft and pump bowl bearings, so periodic overhauls are often necessary. Rather than simply replacing the bearings, however, it is important that repairs address all of the issues needed to restore maximum operating life.

Common Repairs

Common VTP repairs include replacing line shaft and pump bowl bearings, replacing worn shafting, removing corrosion from submerged components and applying corrosion-resistant coatings. Corroded or cavitation-damaged impellers may be repaired and coated or, if badly damaged, replaced.

Pump bowls, suction bells and discharge casings are typically heavy castings that can be reconditioned and fitted with replacement wear rings as necessary. Column sections are similarly reconditioned or replaced if severely corroded.

The discharge elbow that supports the pump (mounted below) and the motor (mounted above) may be less affected by corrosion than submerged components, but special attention is needed to identify and correct any distortion that may have resulted from the heavy stresses applied to this component.

Fit & Alignment

Since line shaft and pump bowl bearings are the most common wear parts for VTPs, repairs should address the fit and alignment of these components. If the discharge elbow and column sections have become distorted, simply replacing the worn bearings will not restore proper running clearances. In that case, the faces and rabbits of the mating components must also be remachined to restore dimensional integrity. Unless special manufacturing equipment is available, this challenging task requires a lathe or boring mill large enough to handle the bulky pump components, and possibly careful engineering to properly support them in the machine tool.

Finish the article online here: https://www.pumpsandsystems.com/best-practices-vertical-turbine-pump-repair

Archives for July 2018

Why Installation & Commissioning Matters.

Best Practices for Vertical Turbine Pump Repair

Common Repairs

Fit & Alignment