My answer to What is difference between a bushing and a bearing?
Answer by Arûn Râinâ:
A bearing is a machine element that constrains relative motion to only the desired motion, and reduces friction between moving parts.
BEARING ARE OF VARIOUS, TYPES LIKE:
- , also known by the specific styles: bushing, , sleeve bearing, rifle bearing
- such as ball bearings and roller bearings
- , in which the load is carried by rolling the axle slightly off-center
- , in which the load is carried by a gas or liquid
- , in which the load is carried by a
- , in which the motion is supported by a load element which bends.
In electric power, a bushing is an insulated device that allows an electrical conductor to pass safely through an (usually) earthed conducting barrier such as the wall of a transformer or circuit breaker.
A bushing must be designed to withstand the electrical field strength produced in the insulation, when any earthed material is present. As the strength of the electrical field increases, leakage paths may develop within the insulation. If the energy of the leakage path overcomes the dielectric strength of the insulation, it may puncture the insulation and allow the electrical energy to conduct to the nearest earthed material causing burning and arcing.
- The disaster bushing will protect the seal from hitting the inside of the stuffing box if you have a bearing failure. This is a very important feature in those applications where the product will burn or explode if overheated.
- The disaster bushing will protect personnel if there is a massive seal failure. The majority of the leakage can be directed, down the drain connection, to a collecting tank or vent.
- To wash away solids from the outboard side of the seal that will prevent "hang up" as the seal face wears and the seal moves forward.
- To wash away toxic or corrosive vapors that might leak across the seal faces.
- To control the temperature in the seal area.
- As a back up to a heating/ cooling jacketing failure.
Disaster bushings are long narrow openings that are located between the pump casing and shaft, that limit the rate of release in event of a catastrophic seal failure.