GRAPHALLOY Provides Advantages in Pump Bushings and Wear Rings

GRAPHALLOY^®, a graphite/metal alloy, is used extensively for pump bushings and wear rings.  It offers two key advantages for pumping applications:

1. GRAPHALLOY enables pumps that run dry, flash, or handle extremely low viscosity fluids to survive without damage.  Numerous case histories and pump manufacturer test results confirm that GRAPHALLOY performs where plastics are unable to stand up and metal parts seize disastrously.

2. GRAPHALLOY enables rings and bushings to be designed with tighter clearances which can improve efficiency, increase output, reduce vibration, throttle seal cavities, or act as a seal backup.  GRAPHALLOY is non galling and dimensionally stable and enables pumps to operate at tight fits without the risk of metal-on-metal rubs or seizure.

Click here to learn more about the use of GRAPHALLOY in pumping applications.

Bushings that Outperform Metal Wear Parts in CO2 Service

Graphite Metallizing Corporation announces GRAPHALLOY^® wear rings and bushings that provide performance superior to standard metal stationary and rotating wear part in pumps for CO2 service in oil field applications. Self-lubricating GRAPHALLOY, a graphite/metal alloy, eliminates concern about bearing failures or possible flashing of CO₂. 

The ability to operate without additional lubrication is important in CO₂ injection applications because CO₂ has low lubricity. Standard metal wear parts rely on the lubricity of the liquid being pumped for proper operation so they are prone to failures in pumps used to inject CO₂. In addition, due to high suction pressure required to keep CO₂ as a dense phase liquid, flashing is always a possibility.

CO₂ injection in older, low flowing wells is becoming an increasingly popular method for permeating rock formations and forcing more oil to the surface. Many older wells still contain vast amounts of oil locked in the pores of rock layers deep underground. CO₂ injection often releases more oil in older wells than can be released by water injection. 

“Use of self-lubricating, non-galling GRAPHALLOY materials in pumps for CO₂ service provides substantial cost savings by avoiding expensive downtime and field repairs caused by wear part failures,” said Eben Walker, General Manager of Graphite Metallizing Corporation. “GRAPHALLOY is currently the material of choice for many oil field applications in North America and around the world.”

GRAPHALLOY wear rings and bushings operate at longer intervals without the need for replacements or maintenance which helps reduce downtime and maintenance expenses. GRAPHALLOY is an excellent choice for any application where service and maintenance tasks are cumbersome or difficult to perform. GRAPHALLOY is a proven solution for even the most challenging plant maintenance and new equipment design applications.

GRAPHALLOY® Plays a Key Role in Geothermal Energy

Crucial to the Success of Pentane Pumps in Geothermal Power

Pentane is a low lubricity, low boiling point liquid. Whenever there is an upset, pumps in pentane service risk galling. Because of the nature of this pumpage, GRAPHALLOY® wear parts are selected to provide a margin of safety and prevent galling.

Why Pentane in Geothermal?

Geothermal power generation must operate with whatever temperature is found in a particular well. Water and steam work well at high temperatures. At lower temperatures, a "binary system" may sometimes provide better efficiency.

In a binary system, the hot fluid from the geothermal source is used to heat a second, lower boiling point fluid (in this case, pentane) to convert it to gas and drive a turbine. The nature of pentane allows the whole cycle (fluid to gas, drive the power generation turbine, and condense to fluid) to take place efficiently at a lower temperature.

At this location, a binary system is being used to squeeze additional power from the hot condensate leaving a primary water/steam turbine. Using an additional set of heat exchangers this energy is captured to heat low boiling point pentane and to drive an additional turbine. The pentane system harnesses more of the energy brought out of the ground.

Like getting something for nothing.

The Challenge
A major U.S. geothermal power plant experienced difficulties with their pentane feed pumps. The pumps are Goulds model 12RJHC-7 stage vertical can pumps. They have a shaft diameter of 1.5 inches with an 18 inch diameter suction can. Each pump is driven by a 125 HP, 1800 RPM electric motor.

Service Conditions

Flow: 966 GPM

Total Developed Head: 476 Feet

Specific Gravity: 0.58 SG

Temperature: 123° F/51° C

Bearings: originally fitted with bronze bearings

The plant's pentane pumps were experiencing deflections on start-up and shut-down. This caused the rotating sleeves to come into contact with the bronze bearings. Because of pentane's poor lubricity, this can cause severe wear or galling and risks damage or seizing of the pumps.

The Solution
To eliminate this problem, the maintenance staff consulted with the engineers at Graphite Metallizing and converted the bowl and line shaft bearings to a GRAPHALLOY bronze grade. The upgrade was a relatively simple procedure allowing the pumps to return to service quickly. The pumps have been in operation without issues for over 3 years.

GRAPHALLOY bearings have been improving the operation of pumps in difficult applications for almost a century. Graphite Metallizing Corporation, the manufacturer of GRAPHALLOY bearings, has been supplying products to companies involved in the production of renewable energy for 50+ years.

GRAPHLON GM 860® — An Abrasion-Resistant Pump Bushing Material

GRAPHLON GM 860® is an abrasion-resistant bushing material that protects pumps and helps prolong pump life. Developed by Graphite Metallizing, the material is a tough, polymer/graphite-based alloy used in the manufacture of pump bushings and other critical-wear parts.

GRAPHLON GM 860® provides exceptional abrasion resistance in harsh environments, has high compressive strength and can handle temperature extremes from -100˚ F to 300˚ F  (-75˚ C to 150˚ C). It is inert to most noxious chemicals, including acid mine water, hydrogen sulfide and jet fuel, and does not swell in water.

GRAPHLON GM 860® was developed as a replacement for traditional pump materials which are prone to damage from highly-abrasive suspensions. River water pumping stations and down hole sump pumps are two examples of key applications. The material also performs exceptionally well under both dry running and severe-duty abrasive-contaminated conditions.

Graphite Metallizing Corp., established in 1913, produces GRAPHALLOY® a graphite/metal alloy bearing material used in the manufacture of self-lubricating bearings and components for machinery and process systems.

GRAPHALLOY® Introduces NSF® Certified Grades For Pumps

Used in Pump Bushings and Bearings for Vertical and Horizontal Pumps

Graphite Metallizing Corporation, the manufacturer of self-lubricating GRAPHALLOY® bushing materials, is pleased to announce that NSF® International, has just certified two grades of GRAPHALLOY material for use in municipal well pumps and water treatment plant applications.

The two newly certified GRAPHALLOY Grades are certified to NSF/ANSI Standard 61 - “Drinking Water System Components/Health Effects” - and approved in the category for Multiple Water Contact Materials (MLTPL) up to 180˚F.

NSF certification is the result of Graphite Metallizing’s rigorous product testing to ensure the highest quality GRAPHALLOY products for the market. These newly certified grades are used in the manufacture of pump bushings and bearings for both vertical and horizontal pumps.

GRAPHALLOY is currently the product of choice for many deep well water pump applications in the western U.S., Hawaii and around the world.

NSF International is the independent, not-for-profit/non-governmental organization that provides materials evaluation, standards testing and product certification services involving public health and safety issues.

Graphite Metallizing Corporation, a global leader in the manufacture of self-lubricating bushings and bearings for almost a century, produces GRAPHALLOY, a graphite/metal alloy bearing material used in the manufacture of self-lubricating bearings and components for pumps, machinery, and process systems.

Replacing leaded bronze in pumps with Graphalloy®

An engineer writes:

Asarcon 520 was a lead impregnated bronze used for sleeve bearing in horizontal split pumps. I have not seen it in use since my days at Worthington Pumps in the late 70’s. It was a material highly specified by the marine industry for on board ships, boiler feed pumps and fire pumps. As you can imagine, lead impregnated bearings were capable of running for short periods of times un-lubricated without the rotor disintegrating. The material was readily available in bar stock, however with the issues associated with lead contamination today, I do not believe it is available in the market any longer. To make sure, I would call the local bearing distributor or and bar stock suppliers and see if a similar material is available under some other name.

Years later, while I worked for Exxon as a Rotating equipment engineer we began using graphite/metal Graphalloy (graphalloy- http://www.graphalloy.com/html/products.html) sleeve bearing for pumps and Thorlon for the slower running centrifuges. We retrofitted some old packing pumps with mechanical seals that operated in hot oil services. These pumps, by design, depended on the packing for shaft support. In order to support the shaft and allow the mechanical seal to live, I installed steel encased Graphalloy (with spiral grooves to convey cooling pumpage) between the bearing housing and the old packing box. This eliminated the run out and allowed the seals to run true and consequently not leak. The Graphalloy material can be used in plain stock or encased in a steel sleeve to add strength, depending on need. In either case you must calculate the loads to assure that the bearing is appropriately designed, can support the shaft loads and you do not located your support at a node in the flexural curve.

Luis