GRAPHALLOY Tames "Bad Actor" Pump

A recent article in World Pumps magazine focused on a major oil refinery in Texas that was experiencing breakage problems with their vertical turbine pump. The plant’s engineers knew that there was a serious problem when the shaft broke twice - in exactly the same place - in less than three years.

The pump was a 4-stage, 14 GH Byron Jackson vertical turbine pump in isopentane service.  A thorough inspection and analysis by the pump repair shop revealed the underlying issue was not with the shaft itself but with the use of the wrong type of bearing materials.

As noted in the article - “Alloy Bearings Cure Breakage Problems” - the bronze bearings should have been able to withstand exposure to the isopentane being pumped. However, there was an occasional inflow of caustic soda which reacted with the bronze.

The bronze bearings were replaced with GRAPHALLOY^® nickel-grade bearings. Since the repair, the pump has been operating efficiently for almost three years with no reports of any problems.

Based on a recommendation from an engineer at the refinery, a GRAPHALLLOY nickel-grade material that would withstand 400°C and offer self-lubricating and corrosion resistant properties was chosen. GRAPHALLOY bushings were installed into the stuffing box, column, bowl and suction bell bearing fits.

According to the sales engineer at the pump repair shop, “GRAPHALLOY is a material that is compatible with a wide range of pumped liquids and offers a good option in high temperature applications.”

GRAPHALLOY resists attack by most corrosive liquids including sulfuric acid, hydrochloric acid, chlorine water and caustics and can withstand high temperatures without deforming or burning.

To read the full article, please click here.

Solution For Off-Shore Platform Firewater Pumps

GRAPHALLOY® nickel-grade bearings have been successfully used in offshore firewater pumps for many years. The non-galling, self-lubricating features of GRAPHALLOY allow pumps to continue working even when they encounter a run dry situation.

This particular firewater pump is installed on a Conoco offshore gas platform in the southern North Sea. The platform is an integral part of the LOGGS pipeline system that delivers gas through a 36" pipeline to a processing terminal on the east coast of England. This platform and pipeline system have been in operation since 1988.

The OEM-specified bushings were simple cut-to-size PTFE/Glass Tape Bearings like those normally found in hydraulic cylinders. High vibration and noise were identified as operational issues. In addition, the compounded PTFE material had little or no dry running capability. This was considered a health and safety issue because the pump was for emergency firefighting service and had to start when needed.

The repair facility had successfully performed several GRAPHALLOY upgrades to firewater pumps for other customers and thus proposed a similar upgrade to Conoco. This upgrade would provide the dry running capability that these pumps lacked.

The engineers at Graphite Metallizing worked closely with the repair facility’s engineering team to define pump modifications required and specify nickel-grade, GM 111.3, GRAPHALLOY bushings.

The upgrade to GRAPHALLOY GM 111.3 bushings was successfully completed. Conoco alsocompleted all required approval tests on the pump successfully. Conoco personnel observed and recorded that the use of GRAPHALLOY significantly reduced noise and vibration levels.

Conoco is now assured that they have an emergency firewater pumping system that has rundry capability and is Health and Safety Executive (HSE) certified

To learn more about GRAPHALLOY, click here.