Bronze Bushings were failing in a car bottom steel ingot heating furnace. With loads of up to 100,000 pounds and temperatures of more than 700° F, the oil failed to keep the bushings lubricated. There was oil on the floor that created a hazardous situation for the workers. GRAPHALLOY® bushings were fitted into the housings to accept the axles of the cart wheels. The bushings have operated for more than two years with no sign of wear.
To learn more about GRAPHALLOY bushings, click here.
GRAPHALLOY Bushings and Bearings
Monday, August 18, 2014
Wednesday, August 6, 2014
Success in Refinery Boiler Feedwater Pumps
GRAPHALLOY® has many years of success in boiler feedwater pump applications. The non-galling, self-lubricating features of GRAPHALLOY allows pumps to continue working even when they encounter a run dry situation.
A Texas refinery has four Ingersoll Rand 6-stage CNTA radial split horizontal pumps in their boiler section. The operating units that use this boiler section have a lot of steam turbine driven equipment.
Demand Changes Can Cause Seizing
Problems occur when the amount of steam needed changes and the rate is quickly increased or decreased. The demand on the steam turbines causes the boiler feed pumps to operate anywhere from shutoff to maximum flow. As the demand for steam increases or decreases, a signal is sent to one of the stand-by pumps to start up or, for an operating pump, to shut down. When this happens, it sometimes starves the operating pump, causing it to momentarily run dry.
When a pump runs dry, metal to metal contact occurs between the rotating and stationary wear surfaces. The wear rings can weld to the shaft, damaging both the rings and shaft. In some cases, the entire pump needs to be overhauled at a substantial cost. Until the failed pump is replaced by a spare, the capacity of the operating unit is reduced, potentially resulting in lost revenues.
The GRAPHALLOY Solution
The refinery installed nickel-grade GRAPHALLOY stationary Wear Rings, Throat Bushings, Throttle Bushings, Channel Ring Bushings and Crossover Center-Stage Bushings in one pump. The second pump was converted to GRAPHALLOY a month later. Both converted pumps survived an ensuing dry run that caused the third, metal-fitted, pump to fail. The third and fourth pumps were then converted to GRAPHALLOY.
Results
The non-galling characteristics of GRAPHALLOY allow the pumps to operate safely at unstable flow rates. After the first year of service following the GRAPHALLOY upgrade, the pumps were operating above the performance curve in both capacity and developed head. In addition, vibration levels were well below the alarm set level.
For more information about GRAPHALLOY, click here.
A Texas refinery has four Ingersoll Rand 6-stage CNTA radial split horizontal pumps in their boiler section. The operating units that use this boiler section have a lot of steam turbine driven equipment.
Demand Changes Can Cause Seizing
Problems occur when the amount of steam needed changes and the rate is quickly increased or decreased. The demand on the steam turbines causes the boiler feed pumps to operate anywhere from shutoff to maximum flow. As the demand for steam increases or decreases, a signal is sent to one of the stand-by pumps to start up or, for an operating pump, to shut down. When this happens, it sometimes starves the operating pump, causing it to momentarily run dry.
When a pump runs dry, metal to metal contact occurs between the rotating and stationary wear surfaces. The wear rings can weld to the shaft, damaging both the rings and shaft. In some cases, the entire pump needs to be overhauled at a substantial cost. Until the failed pump is replaced by a spare, the capacity of the operating unit is reduced, potentially resulting in lost revenues.
The GRAPHALLOY Solution
The refinery installed nickel-grade GRAPHALLOY stationary Wear Rings, Throat Bushings, Throttle Bushings, Channel Ring Bushings and Crossover Center-Stage Bushings in one pump. The second pump was converted to GRAPHALLOY a month later. Both converted pumps survived an ensuing dry run that caused the third, metal-fitted, pump to fail. The third and fourth pumps were then converted to GRAPHALLOY.
Results
The non-galling characteristics of GRAPHALLOY allow the pumps to operate safely at unstable flow rates. After the first year of service following the GRAPHALLOY upgrade, the pumps were operating above the performance curve in both capacity and developed head. In addition, vibration levels were well below the alarm set level.
For more information about GRAPHALLOY, click here.
Tuesday, July 15, 2014
GRAPHALLOY® Keeps Subsea Hose Reels Turning
Cleaning underwater piping was a problem for a leading oil company...until they installed GRAPHALLOY® bearings.
The oil company was upgrading their existing underwater piping. Before the old piping could be removed, it had to be cleaned and purged. The cleaning operation utilizes a set of four subsea hose reels that were mounted to a skid and dropped to the bottom of the ocean floor. The hoses flush the cleaning fluid through the pipes.
This particular operation required a new, larger hose reel design. The babbitt-lined sleeve bearings used on previous hose reels would not be able to handle the increased load and, as such, superior bearings were needed. These bearings are crucial to successful operation because they permit the hose reel to turn without the use of oil or grease.
The oil company, working with engineers at Graphite Metallizing, decided to test two of the 163 Series Pillow Blocks with Bronze GRAPHALLOY® bushings in one of the larger hose reels. The test, which was performed in their assembly shop, required that the bushings operate at twice the estimated work load.
The test was successful. The GRAPHALLOY bushings had worked as expected and the shaft was not damaged.
As a result, the oil company ordered a large quantity of the GRAPHALLOY pillow blocks and installed them on hose reels that were shipped off-shore. GRAPHALLOY bushings are now specified on all of the company’s larger, maintenance-free hose reels.
Once again, GRAPHALLOY provides reliable, problem-free solutions for the most difficult applications.
The oil company was upgrading their existing underwater piping. Before the old piping could be removed, it had to be cleaned and purged. The cleaning operation utilizes a set of four subsea hose reels that were mounted to a skid and dropped to the bottom of the ocean floor. The hoses flush the cleaning fluid through the pipes.
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| Subsea hose reel |
The oil company, working with engineers at Graphite Metallizing, decided to test two of the 163 Series Pillow Blocks with Bronze GRAPHALLOY® bushings in one of the larger hose reels. The test, which was performed in their assembly shop, required that the bushings operate at twice the estimated work load.
The test was successful. The GRAPHALLOY bushings had worked as expected and the shaft was not damaged.
As a result, the oil company ordered a large quantity of the GRAPHALLOY pillow blocks and installed them on hose reels that were shipped off-shore. GRAPHALLOY bushings are now specified on all of the company’s larger, maintenance-free hose reels.
Once again, GRAPHALLOY provides reliable, problem-free solutions for the most difficult applications.
Thursday, July 3, 2014
GRAPHALLOY® Survives Where Plastic Fails
A major oil company’s chemical plant was experiencing run dry failures with a multistage axially split cased pump in a hydrocarbon process service. The plant was operating with batching requirements rather than continuous feed. As a result of the batching requirement, the operators and instrumentation were unable to prevent run dry transients from occurring.
The plant engineers had approved modifying the pumps to incorporate plastic composite wear rings and sleeves on the rotating assembly. These modifications were made in hopes of preventing pump failures during the dry running upsets. After modification the pump continued to experience dry running upsets and the plastic composite materials failed.
This pump is a multistage volute style with a flow crossover so that some of the stages work in the opposed direction to help balance thrust. The rotor utilizes stationary and rotating wear rings on the eye and hub side of the impellers as well as inter-stage bushings, center bushing and throttle bushing.
Operating conditions:
The repair service company completed the installation and returned the pump to service. Upon start-up the pump ran smoothly. Over the next several months, this pump experienced four separate incidents where the pump was run dry for four to eight minutes. GRAPHALLOY allowed the pump to operate through these transients without shutdown or failure because of its non-galling/self-lubricating features.
Since installing GRAPHALLOY, the plant operators have not observed any fluctuations in the pump’s performance (throughput and pressure) and vibration levels have remained constant. The end user is pleased with the results of the GRAPHALLOY upgrade.
Read more about the success of GRAPHALLOY in pumps.
The plant engineers had approved modifying the pumps to incorporate plastic composite wear rings and sleeves on the rotating assembly. These modifications were made in hopes of preventing pump failures during the dry running upsets. After modification the pump continued to experience dry running upsets and the plastic composite materials failed.
This pump is a multistage volute style with a flow crossover so that some of the stages work in the opposed direction to help balance thrust. The rotor utilizes stationary and rotating wear rings on the eye and hub side of the impellers as well as inter-stage bushings, center bushing and throttle bushing.
Operating conditions:
- Temp: 350̊F
- Flow: 370 GPM
- TDH: 2020 ft
- Speed: 3560 RPM
- Motor Drive
The repair service company completed the installation and returned the pump to service. Upon start-up the pump ran smoothly. Over the next several months, this pump experienced four separate incidents where the pump was run dry for four to eight minutes. GRAPHALLOY allowed the pump to operate through these transients without shutdown or failure because of its non-galling/self-lubricating features.
Since installing GRAPHALLOY, the plant operators have not observed any fluctuations in the pump’s performance (throughput and pressure) and vibration levels have remained constant. The end user is pleased with the results of the GRAPHALLOY upgrade.
Read more about the success of GRAPHALLOY in pumps.
Thursday, June 19, 2014
GRAPHALLOY Material Receives Drinking Water System Approval
Graphite Metallizing Corporation continues to expand the GRAPHALLOY® product line to meet drinking water regulations worldwide.
Graphite Metallizing Corporation is pleased to announce that GRAPHALLOY® Grade GM 695.3 Bearings have been granted Water Regulations Advisory Scheme (WRAS) approval. This follows the recent certification of NSF/ANSI grades as Graphite Metallizing continues to expand the GRAPHALLOY product line to meet drinking water regulations worldwide.
Through a stringent testing process, WRAS approval indicates that the GRAPHALLOY bearings comply with the high standards set out by the water regulations within the United Kingdom.
In addition, WRAS approval specifies that GRAPHALLOY GM 695.3 Bearings are “suitable for contact with wholesome water for domestic purposes” because it has met the requirements of BS 6920-1:2000 (“Suitability of non-metallic products for use in contact with water intended for human consumption with regard to their effect on the quality of water”).
Bushings made of WRAS approved GRAPHALLOY are used in municipal water system pumps. These bushings have been found to operate for more than 10 years in these services and to provide solutions that eliminate requirements for lubrication systems, including pre-lubrication.
Graphite Metallizing Corporation is pleased to announce that GRAPHALLOY® Grade GM 695.3 Bearings have been granted Water Regulations Advisory Scheme (WRAS) approval. This follows the recent certification of NSF/ANSI grades as Graphite Metallizing continues to expand the GRAPHALLOY product line to meet drinking water regulations worldwide.
Through a stringent testing process, WRAS approval indicates that the GRAPHALLOY bearings comply with the high standards set out by the water regulations within the United Kingdom.
In addition, WRAS approval specifies that GRAPHALLOY GM 695.3 Bearings are “suitable for contact with wholesome water for domestic purposes” because it has met the requirements of BS 6920-1:2000 (“Suitability of non-metallic products for use in contact with water intended for human consumption with regard to their effect on the quality of water”).
Bushings made of WRAS approved GRAPHALLOY are used in municipal water system pumps. These bushings have been found to operate for more than 10 years in these services and to provide solutions that eliminate requirements for lubrication systems, including pre-lubrication.
Thursday, June 12, 2014
GRAPHALLOY® Bearings Operate at -269°C
Turbomachinery International magazine reported on a project at Vienna University of Technology's Atominstitut using GRAPHALLOY at -269°C.
The article - "Maintaining Lubricity at Cryogenic Temperatures" - describes the key role of GRAPHALLOY in building a Rotating Sample Magnetometer to measure magnetic properties of samples, usually at temperatures near zero.
"When designing pumps, compressors, valves and ancillary components for cryogenic applications, one is concerned with more than the ability of the components to withstand the low temperatures without shrinking, becoming brittle, losing strength or cracking.
Whenever there are moving parts, there is the need to minimize friction and wear, and to prevent sticking or galling. Unlike higher-temperature applications, the use of fluid lubricants in low temperatures is out of the question...
Recently, the GRAPHALLOY material hit a new record low temperature application in a magnetometer. It was not quite as low as what the CAL will reach, since those can only be achieved in space, but it was not much warmer."
Click here to read the full article.
The article - "Maintaining Lubricity at Cryogenic Temperatures" - describes the key role of GRAPHALLOY in building a Rotating Sample Magnetometer to measure magnetic properties of samples, usually at temperatures near zero.
"When designing pumps, compressors, valves and ancillary components for cryogenic applications, one is concerned with more than the ability of the components to withstand the low temperatures without shrinking, becoming brittle, losing strength or cracking.
Whenever there are moving parts, there is the need to minimize friction and wear, and to prevent sticking or galling. Unlike higher-temperature applications, the use of fluid lubricants in low temperatures is out of the question...
Recently, the GRAPHALLOY material hit a new record low temperature application in a magnetometer. It was not quite as low as what the CAL will reach, since those can only be achieved in space, but it was not much warmer."
Click here to read the full article.
Tuesday, April 22, 2014
Is GRAPHALLOY A True “Run-Dry” Material?
GRAPHALLOY® is an alloy of carbon graphite and metal. The
graphite provides continuous lubrication without the need for grease
oil or other forms of lubrication. GRAPHALLOY deposits a thin film of
graphite on the shaft to reduce friction and the metal impregnate help
to transfer heat from the rubbing surface to the housing. GRAPHALLOY
has much higher temperature limits than many thermoplastics available
today. Run-Dry transients will not melt the GRAPHALLOY as it may do to
other materials. Normally the pumps can be put back in service
immediately after dry running transients while plastics usually require
replacement.
For more answers to questions about GRAPHALLOY, click here.
For more answers to questions about GRAPHALLOY, click here.
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