4 Benefits of Rebowling For Vertical Turbine Pumps

Vertical turbine pumps may perform 10-15 years without issue in clean water applications. Some even longer. Eventually, the pump will show evidence of wear. Perhaps multiple pumps will run whereas only one ran before. One might hear vibration or cavitation inside the pump. 

If lost performance or excessive noise becomes evident in a vertical turbine pump, it may be time to consider a rebowling service.

VERTICAL TURBINE PUMPS

Vertical turbine pumps consist of a motor, discharge head, one or more pipe columns (flanged or threaded), line shaft, pump shaft, and multiple bowls, impellers, and a suction bell. Oftentimes a basket strainer is attached to the suction bell of the bowl assembly to prevent large solids from entering the pump. Often, the strainer may be missing after years of service due to corrosion, falls off. 

Over time, the performance and operation of vertical turbine pumps can dramatically decline. A drop-off in performance is marked by:

• Excessive vibration
• Cavitation
• Head loss

These issues are commonly traced back to the bowl assembly. Impellers wear due to cavitation, corrosion, or extended use. Clearances open up, thus opening the door to vibration issues. Due to its length, even small vibrations at the end of the shaft can cause major issues for components like line shaft wear at bearing location as well as mechanical seal. 

WHAT IS REBOWLING

Many vertical turbine pumps operate trouble-free for years. The only way an unfamiliar person may suspect a problem with their vertical turbine is leaky packing or mechanical seal, motor vibration, or pump failure.

The signs are easy to miss because most of the pump is below the floor. By the time the pump is removed from service, the shaft is already worn at the bearing locations, and wear ring clearances have opened, causing the decrease in performance.  If the wear is significant, it is often more cost-effective to consider a rebowl.

Simply put, rebowling is the replacement of the bowl assembly on a vertical turbine pump. A vertical turbine rebuild expert removes the current bowl assembly and replaces it with new. The following checks are made:

• Materials upgrades to impellers, shafts
• Upgraded replacement components
• Opportunity to reestablish performance conditions

WHY REBOWLING INSTEAD OF REPLACEMENT

1. No disruption to the existing pipe - When rebowling an existing vertical turbine pump, the discharge head is unchanged. The pump can easily be removed for service, then replaced without piping disruption. 
2. New or upgraded performance, reduced operating cost - Most vertical turbine pumps requiring rebowling spent 10 or more years in service. Many upgrades in materials and technology occur and can be implemented at this time.
3. Economical option compared to pump replacement - When rebowling a vertical turbine pump, it’s likely one will achieve the performance needed without replacing the entire pump. No piping changes are necessary. It’s possible lead time is shortened as only the bowl assembly is needed, not motors, columns, and other components. 
4. Ability to address process changes - If a process has changed, or needs to change, rebowling can accommodate the change in operating conditions. 

When considering a pump repair shop for rebowling, find one serious about pump repairs with experience with vertical turbine pumps. Read more about how to spot a shady pump repair shop here. 

Rebowling is an easier and more economical alternative to a complete vertical turbine pump replacement. Talk to an engineer with experience in vertical turbines to determine if rebowling services are right for your pump.