Carbon Sliding Bearing Capabilities
Morgan Advanced Materials group have been developing Carbon Bearings for over 30 years. The term Carbon Bearing can cover “carbon-graphite”, “metal-graphite” and “electro graphite”. Carbon is a self-lubricating material with a low coefficient of friction at high and low temperatures. This quality lends itself to a wide range of uses as a bearing or bushing material in cases where a conventional lubricant is not available and where other lubrications perform poorly. Other advantageous properties include:
- Low wear rate
- High thermal conductivity
- High resistance to thermal shock
- High-temperature capability (up to 500°C grade dependant)
- High strength to weight ratio
- Electrically conductive
- Chemically inert
- Mechanically strong in compression
Read on to learn how these properties can be useful in bearing design and applications. For expert bearing design and grade selection advice, contact us today!
Where are Carbon Bearings used?
Carbon bearings have a broad field of use in applications where it would be difficult or impossible to lubricate bearings with oil or grease. The three principal fields of use are:
- Preventing contamination such as in textile and food machinery (by avoiding oil or grease)
- High-temperature applications such as those found in furnace and boiler equipment where conditions are too hot for the use of conventional lubricants
- Immersion in liquids such as hot and cold water, seawater, acidic or alkaline solutions, or in oil solvents such as petrol and benzene
Carbon Bearing Design Arrangements
Any bearing design should be undertaken in collaboration with material experts and the following information is merely a guide to considerations for your bearing design. For expert advice on your bearing application, contact us today.
The three types of design arrangement include radial bearings, axial bearings and flanged bearings. There are certain general precautions to be taken in designing any bearing arrangement such as an awareness of shaft deflection and the application's thermal range to mitigate high load conditions between the shaft and bearing. The potential for system contamination must also be considered. Potential solutions include self-aligning bearings and the use of slots and grooves on the bore or faces.
Carbon Bearing Fitting Methods
There are 4 methods of fitting carbon bearings which can be used according to project needs. These are Shrink-Fitting, Press-Fitting and Slack-Fitting and Split-Bearing Fitting. The use of split bushes should be avoided if possible as they are more susceptible to breakage than solid bushes.
Carbon Bearing Dry Operation Applications
- Conveyors: In food, textile, and chemical industries where it is necessary to exclude free oil or grease.
- Scroll Conveyors: Handling powders, where conventional bearings are not possible.
- Foundry Slat Conveyors: Where temperature and conditions render conventional bearings unsuitable.
- Chain Grate Stokers: Industrial and electricity generating station plant where temperatures prohibit conventional bearing lubrication.
- Boiler Plants: Flue gas, induced and forced draft damper and spot blower bearings on boiler equipment, where temperatures prevent normal lubricated bearings being employed.
- Furnace and Oven Plants: In furnace roller and furnace charger roller bearings in the steel industry, bearings on oven conveyors and continuous belt ovens etc. The use of normal lubricated bearings is impracticable due to temperature.
- Veneer and Paper-Drying Machines: Carbon bearings are highly suitable as contamination by conventional lubricants must be eliminated and temperatures are sufficiently high to cause lubrication difficulties with normal bearings.
- Rollers on Micro-Switches: Presence of oil or grease undesirable. Complete carbon roller contacts very satisfactory.
- Textile Machinery: Cloth drying plant, stentering machines, synthetic fibre spinning, etc. Contamination by oil or greases must be avoided at all costs.
- Soaking Pit Covers: In the steel industry where temperatures prohibit normal bearings. Main support roller bushed with carbon bearings highly suitable.
Carbon Bearing Wet Operation Applications
- Centrifugal Pumps: Impeller steady bearings operating immersed in various liquids. Carbon used for steady bearings.
- Gear Pumps: Main gear bearings, lubricated by the liquid being pumped.
- Fuel Metering Pumps: Bearings operating immersed in fuels, such as petrol, paraffin, kerosene, etc.
- Submersible Pump Units: Carbon bearings used in many positions of such equipment, both in the pump and drive motor, including main motor bearings and thrust pads which operate immersed in filtered water.
- Glandless Centrifugal Pumps: Main impeller bearings lubricated by the liquid being handled.
- Central Heating Circulating Pumps: Main impeller bearings in carbon operating immersed in hot water.
- Bottle Cleansing Plants: Carbon bearings are employed in situation subjected to cleansing fluids, which prevent the use of conventional lubricated bearings.
- Chemical Plants: Mixing vessels, agitators, etc., carbon used as steady bearings in a variety of chemical liquids.
- Textile Industry: Dye Jigs where carbon bearings operate both immersed in and above the dying solution. Also used in the wet spinning of synthetic fibres, where carbon bearings are splashed with acidic liquids.
- Automatic Washing Machines: Carbon bearings used as main impeller bearings, operating immersed in hot water
- Liquid Measuring Meters: Miscellaneous carbon bearings in this equipment, running in various liquids.
For more details, download our full bearing design guide and to get a tailored grade recommendation, contact our technical experts today!