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Bearing Repair Process

July 27, 2016

Electric generation companies make their money when it is hot outside. Consequently, they keep their machines running or available in the summer. Maintenance usually happens in the spring or fall…when the temperature is moderate.

Consequently, we have had some time at TRI to work on our web site. We undertook a big job to redesign it with a layout that will work devices of all size. We want it to look good on your desktop as well as your smart phone.

Our initial job is complete, but now we are adding more content for our customers.

Our latest addition is the Bearing Repair page. This page does more then just tell potential customers that TRI Transmission and Bearing Corp. repairs bearings. It is a bullet list of the steps bearings get when they come in the door. The list has been published so our customers understand what goes into a bearing repair.

When a bearing is sent to TRI during the summer, it usually means a machine is in an unscheduled outage. Unscheduled outages are expensive so it is critical that the repairs be done ASAP. When TRI goes to an expedited schedule, we work on the bearing repair 24 hours a day, 7 days a week. It’s important to us that the customer knows exactly what we are doing and how far along we are in the process.

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Pressure Dam and Elliptical Bore Bearings

July 7, 2016

It’s been a while since our last Tech Note, but TRI has released a new tech note. This installment explains how pressure dam and elliptical bore bearings are used to control sub-synchronous vibrations and then explains why TRI prefers the elliptical bore bearing to the pressure dam.

Download the Tech Note

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Animation: Tilt Pad Bearing With Ears

May 23, 2016

TRI has released a new animation of a tilt pad bearing. The bearing in this animation has hold down ears. An earlier video explaining the advantages of the hold down ears versus the clamping method earlier.

 

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Dr. Mel’s Opinion on the deregulation of power generation

May 3, 2016

In the fall of 1998, Dr. Mel Giberson wrote an opinion piece for Turbo Machinery Magazine regarding the market deregulation of electric power generation. The points discussed nearly 20 years ago, still hold true today. The piece is available on the TRI Web site.

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Tilt Pad Bearing Assembly

April 29, 2016

TRI has released a new video showing the assembly of a simple tilt pad bearing.

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Lift Oil Pumping System

March 21, 2016

TRI has recently completed a pair of lift oil pumping skids. They will produce 5 gallons per minute at 3000 p.s.i. The system will reduce the wear on bearings when the unit is on turning gear. The lift oil will also reduce the load on the turning gear and turning motor.

LiftOilSystem

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TRI’s Bearing Design Philosophy Regarding Bearing Clamping Methods

June 15, 2015

The following write up is from section 1 of the Catalog of TRI Journal Bearings which can be downloaded from www.turboresearch.com

Many rotating equipment manufacturers seat a bearing in an end wall of a bearing standard / pedestal and use the standard cover to hold the bearing in place. This design method is definitely simple and low cost, and it works when the air temperature surrounding the bearing standard / pedestal is “ambient”, i.e., not heated.
However, there are applications for which this clamping design is not very effective and even inappropriate. For applications where the wall of the standard/pedestal is heated by exposure to hot steam escaping from shaft seals of a turbine, or is exposed to the radiant heat from an adjacent hot turbine, the standard / pedestal wall grows due to thermal expansion. While the bearing inside is cooled with lube oil in the neighborhood of 130 to 160 deg F, the external heating may cause the temperature of the standard wall to increase to 250 deg F. For a fit diameter of 32 inches and a temperature differential of 100 deg F, a gap between the two grows by 0.020 inches (0.5 mm) so that the bearing gets quite loose in the fit, even if clamped with a slight interference when installed cold. Looseness of bearings contributes greatly to increased rotor and bearing vibrations, as well as fretting of the bearing seat, which is why TRI considers this design to be inappropriate for hot steam turbine applications.
Consequently, where possible, TRI prefers to use a bearing clamping design wherein the bearing top half has an integral “strongback”, and the ears of the top half are bolted directly to the horizontal joint, as shown on Page 3. In this case, the standard cover can get hot and expand, but the bearing remains tightly fastened to the lower half. In a number of retrofit cases of TRI journal bearings, bolt holes are drilled and tapped into the horizontal joint and the standard cover is milled way to provide space for the ears of the bearing top half to fit.
This design of a top half bearing with ears and hold down bolts into the horizontal joint is definitely more expensive than fitting a round bearing into a hole in a wall, but the long term benefits of vibration control for light weight, high speed, high power density turbine rotors cannot be matched any other way.
It is important to give proper credit for the origination of this design feature. GE Engineers in Schenectady, New York developed this design method in the 1930s for the very reasons cited above. It became a standard GE bearing design feature by approximately 1940.
Through many years of solving severe bearing damage problems and various difficult rotor vibration issues, TRI has developed a large repertoire of bearing designs that were “custom or special designs” at the time, but which over the years have become “TRI standard bearings”. Many are now relatively popular designs.
TRI continues to design and manufacture the journal bearings presented in this catalog, or similar bearings adapted to meet customer’s specific needs, or other designs to suit new applications.

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