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Fluid Drive Upgrades To Maximize Reliability

Large fluid drive for boiler feed pump

Fluid Drives, also known as “Hydraulic Couplings”, can be very reliable. In fact, fluid drives that are designed correctly are more reliable with lower cost maintenance than other forms of variable speed drivers such as mechanical drive steam turbines and electronic variable frequency drives.  A typical time frame between routine inspections of a Fluid Drive designed and built by TRI is approximately 10 to 12 years. 

However, many aging fluid drives from other manufacturers are not trouble free.  In many cases, the operating conditions may have changed from the original design for which the fluid drive was installed new.  Consequently, there are many older fluid drives made by other manufacturers which can only operate at higher speeds without much slip. Slip conditions generally associated with mid-load generation conditions cause the fluid drive circuit oil to heat up and can lead to high amplitude rotor vibrations if the bearings are not selected properly.

In 1973, TRI began solving the reliability issues of the higher-power Gyrol® Fluid Drives (3600 rpm input and up to 3510 rpm output) for Boiler Feed Pump (BFP) service that existed at the time. An early name for the manufacturer of these drives was American-Blower, succeeded by American-Standard and Howden. The Gyrol® fluid drive is now built by Kraft Werks Engineering.

As a result of developing solutions to the reliability issues of these fluid drives in the 1970s through the early 1990s, especially vibration and bearing damage problems, TRI developed the “TRI Heavy-duty Fluid Drives” which are capable of operating over the entire capacity and head ranges of the driven boiler feed pumps.  TRI’s proven solutions have been in operation for over 30 years, and in particular, they typically can operate smoothly with large turn down speed ratios.

TRI is the primary support company for many of these fluid drives today, and TRI can refurbish/ repair/ replace any one of them. This includes: 

  • providing spare parts that are generally made with improved materials and design features 
  • refurbishing rotating elements, including during emergency outages 
  • refurbishing complete fluid drives
  • providing Consulting Engineers for field service work to direct inspection and repair on site
  • provide new shaft seals to resolve oil leakage problems
  • solving oil level control issues
  • installing upgraded vibration monitoring (x-y proximity probes) systems
  • installing upgraded temperature sensing instrumentation (thermocouples or RTDs)
  • resolving problems of flexible couplings from the power source or to the boiler feed pump
  • manufacturing completely new fluid drives or new rotating elements with increased power
  • solving overheating problems that may occur in certain load ranges
  • providing upgraded powerful brakes to replace early magnetic brakes or hydraulic brakes

Other Fluid Drives that TRI refurbishes are Fluidrive Engineering, Nelson, and certain Voith® Fluid Drives.

Back in 2007, Dr. Mel created a presentation for fluid drive upgrades. This presentation explains how fluid drives are used specifically with boiler feed pumps. The operational history and the changes to the standard practices led to issues for which TRI has engineered solutions.