GRAPHALLOY OPERATES at High Temperatures

In the SMR process gas cooler, the flow of the 1400oF hydrogen stream is controlled by blade and butterfly dampers. The OEM furnised bearings supporting the damper shafts often seized, making the regulation of the process difficult. They were replaced with GRAPHALLOY grade GM GDG-2 bushings. Inspected after several years of trouble-free operation in this high temperature environment, the GRAPHALLOY bushings were found in excellent condition with the shafts free to rotate.

GRAPHALLOY Increases Equipment Life

The horizontal reactor shaft bushing supports the circulating impeller and internal mechanical seal in this continuous duty application. Although the combination of a low lubricity sealing fluid, intermittent slugs of concerntrated sulfuric acid, and high bearing load creates a trouble some environment for other bearing materials, self-lubricating GRAPHALLOY will provide superior performance. It resists the acid chemical attack. It does not deform under load and maintains a close running clearance . At one installation the GRAPHALLOY bushing had only .003" wear after four years of operation.


Lube oil stock mixed with MEK and toluene is fed through the chiller to crystallize the wax in solution. The interior scrapper assembly bushings are subjected to temperature swings and attacked by harsh chemicals. GRAPHALLOY works in this environment. It remains dimensionally stable under load and close operating clearance is maintained regardless of the temperature changes. At one refinery, GRAPHALLOY bearings have run four times longer with less than one-half the measurable wear of the original bronze bearings.

GRAPHALLOY Reduces Vibration

Excessive shaft vibration can cause repetitive mechanical seal failures in process pumps. A non-galling, close clearance GRAPHALLOY throat bushing lowers the shaft deflection and improves rotor stability. It also reduces flush liquid consumption. This application is recognized in the current API 682 standard.

GRAPHALLOY Delivers Reliable Operation

Pumping recirculated creosote is always a maintenance headache. The liquid is hot, gritty and provides no lubricity to internal pump parts. One operator tried bronze, plain carbon and tungsten carbide for the idler bushing, but never obtained an operating period greater than 150 hours. Switching to GRAPHALLOY increased service life to over 400 hours.

GRAPHALLOY Simplifies Maintenance

Damper bearings in the power house have always caused maintenance problems due to heat and poor lubrication practices. Changing to dry GRAPHALLOY material eliminates the need for any lubricant which would burn-off, gumup or harden at these higher temperatures. At one installation, the upgrade to GRAPHALLOY flange blocks resulted in maintenance-free operation for more than seven years.

GRAPHALLOY Survies Loss of Suction

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


Self-lubricating GRAPHALLOY is now the bearing material standard for vertical "can" pumps in the refinery tank farm area. Bronze bearings had proven unsatisfactory when pumping the light hydrocarbon products because of the liquids' poor lubricity and tendency to "flash". This, combined with "dry running" when the tanks emptied, motivated operators to select GRAPHALLOY (confirmed by the API 610 Eighth Edition) for lower wear rates and "run dry" survival.