Graphalloy

graphalloy

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Bearings for pump survival

What is GRAPHALLOY?

GRAPHALLOY, graphite/metal alloy is a self-lubricating bearing material used by designers and maintenance engineers to solve the toughest pump applications-from new installations to retrofitting existing units. GRAPHALLOY is non-galling, corrosion resistant, dimensionally stable and performs at temperatures from cryogenic to higher than 1000 F. GRAPHALLOY allows pumps to survive “run dry” conditions, slow roll operation and frequent stops/starts where metal and plastics fail. GRAPHALLOY works in low lubricity, corrosive and sour liquids. The use of GRAPHALLOY pump wear parts results in lower operating and repair costs and provides assurance against catastrophic failures.

GRAPHALLOY, graphite/metal alloy, is a dry, self-lubricating material with a low coefficient of friction. Available in over 100 grades impregnated with, Babbit, Tin Babbit, Copper, Bronze, Silver, Nickel, FDA Accepted Grades and others. GRAPLON a chemically inert material used on submerged applications that are subject to abrasion, shock or impact. GRAPHALLAST a low friction material used on submerged applications that are subject to abrasion, shock or impact.

What Makes it Work Better

features benefits

Self-Lubricating

Handles low lubricity fluids such as light hydro­carbons, liquefied gases and hot water in which metallic bearings wear excessively.

Hot

Runs at temperatures well above the limit of plastic-even in molten metals above 1000' F-and survives thermal shocks of 22 degrees per second down to ambient.

Cold

Performs in cryogenic temperatures to -450° where other materials suffer embrittlement and seizure

Dry Running

Survives "loss of pumpage" operation for pro­longed periods without either damage or pre­venting pump re-start.

Wet

Resists attack by most corrosive liquids includ­ing sulfuric acid, chlorine water, and caustics.

Non-Galling

Permits closer running clearances between rotating parts resulting in higher pump efficiency and lower shaft vibration.

Dimensionally Stable

Maintains dimensional stability when sub­merged, under static pressure loading, and over wide temperature swings, providing constant running clearance for all operating conditions.

THE QUESTION

HOW MUCH CAN GRAPHALLOY IMPROVE PUMP OPERATION?

THE ANSWER

SPECIFYING GRAPHALLOY PROVIDES REAL ADVANTAGES

GRAPHALLOY Reduces Vibration

Pumps with mechanical seals have frequent failures due to excessive shaft vibration. Upgrades using GRAPHALLOY case rings and close clearance throat bushings provide reduced vibration levels-in one spe­cific case from 1.2 to less than .05 ups. The result is lower seal and bearing failures and increased MTBF. This upgrade us recognized in the current API 682 standard. GRAPHALLOY more than meets this specification

GRAPHALLOY Extends Life for Continuous Sevice

Self-lubricating GRAPHALLOY has long been the standard bearing in vertical “can” pumps in the refin­ery tank farm area. The typical light hydrocarbon products have poor lubricity and tendency to “flash”. This, combined with recurring run dry” operation when the tanks emptied, motivated designers and operators to search for a replacement of the bronze bearing material GRAPHALLOY is now the over­whelming choice (confirmed by the API 610 Eighth Edition) for lower wear rates and “run dry” survival.

GRAPHALLOY Survives Frequent Loss of Suction

Boiler Feed pumps for industrial steam generators are frequently sub­jected to loss of suction flow during transient switch over. Pumps fitted with metal and plastic wear parts fail In a few minutes of dry running, while those fitted with GRAPHALLOY will survive and resume pumping when flow returns without wear parts damage. At a chemical plant, three pumps experienced 25 failures in eight years at a cost of $15,000 per failure. Following a GRAPHALLOY retrofit of all pumps, failures were reduced by 68% and the average repair cost by over 90%, during the next five years

GRAPHALLOY Permits Dry Starts

Deep satting vertical turbine well pumps require pre-lubrication of the standard bronze or rubber bearings between the low water level and the dis­charge surface. Environmental concerns have now restricted the use of oil and grease. The alternate of water from a local source for start-up requires a complicated auxiliary system. The solution is to use GRAPHALLOY lineshaft bushings which eliminate the need for any pre-lubrication by running dry until pump dis­charge flow is established. At one installation, the engineer estimated that it would take more than five minutes for the pumpage to reach the surface discharge from lower water level. GRAPHALLOY survived this duration with margin to spare.

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