Bearings monitoring

Hot running Preventive maintenance bearings., Monitor bearings temperature Purging and sealing to keep solvents out, if solvent (even vapor) exposure is possible Use improved bearing lubricant CCPS G-29... 

Centrifugal (radial inflow) turboexpanders are well adapted to such energy conservation schemes and, with recent developments that have increased their reliability, are suitable for unattended service on a 24-hour, 7-day week operational basis. Some of the recent developments include better shaft seals, thrust bearing monitoring, and superior control devices. 

The standard bearing monitor solves the most basic problem common to all sealless pumps—detecting normal bearing wear so that routine maintenance can be accomplished before serious motor damage occurs. It responds to bearing wear in both the axial and radial directions and is over 98% effective on 70,000 operational units. 

Since the higher thermal conduc tivity material (copper or bronze) is a much better bearing material than the conventional steel backing, it is possible to reduce the babbitt thickness to. 010-030 inch. Embedded thermocouples and RTDs will signal distress in the bearing if properly positioned. Temperature-monitoring systems have been found to be more accurate than axial-position indicators, which tend to have linearity problems at high temperatures. 

Improved sensors allow computer monitoring of the system for safety and protection of the equipment from damage. Sensors include lubrication-flow monitors and alarms, bearing-temperature sensors, belt scales, rotation sensors, and proximity sensors to detect ore level under the crusher. The latter prevent jamming of the output with too high an ore level, and protect the conveyor from impact of lumps with too low an ore level. Motion detectors assure that the conveyor is moving. Control applied to crusher systems including conveyors can facilitate use of mobile crushers in quarries and mines, since these can be controlled remotely by computer with reduced labor. 

Running unbal- Preventive maintenance and operator checklist anced, vibration inspections due to worn bear-, effective vibration monitor/shutdown device ings or other mechanical problem such as product accumulation behind filter screen. ... 

Heat build-up Ensure frequent preventive maintenance checks due to worn or on bearings overloaded, Monitor and alarm bearing temperature bearings. Ensure proper belt tension CCPS G-12 CCPS G-23 CCPS G-29... 

Thrust bearings, often the most problematie eomponent in highspeed maehinery, ean be aeeurately monitored and eontrolled. 

The Automatie Thrust Balanee System is a dynamie adjusting system. Hydrodynamie pressure at the thrust bearing faee, an indieation of thrust loads, is eontinuously monitored and fed to either side of a piston, whieh, in turn, adjusts the pressure aeting behind the eompres-sor wheel. 

Monitoring should include the usual parameters worthy of surveillance in high-speed turbo machinery the temperature of journal bearings, vibration and axial position of the pinions, inlet and discharge temperatures combined with discharge pressure from the individual compressor stages, and various lube oil system devices. Competent manufacturers make sure all measurement locations are completely prewired on the machine and made available at predefined interfaces or in terminal boxes for connection at the plant site. 

API Std 614 Lubrieation, Shaft-Sealing, and Control-Oil Systems for Speeial-Purpose Applieations API Std 670 Vibration, Axial-Position, and Bearing-Temperature Monitoring Systems ASME BPV Seet 11 Materials... 

Continuous monitoring of unit operation providing information on rotor location, balance, speed, and bearing loads, which were previously difficult and costly to obtain. 

In a radial active magnetic bearing, the rotor is held in position by electromagnets located on the stator (Figure 6-3). The rotor-to-stator position is constantly monitored by sensors that communicate with the electronic control system. If the rotor deviates from its position, the control system adjusts the current flow to the electromagnets to return the rotor back to its proper position. 

An active magnetic axial bearing consists of two stators and a rotor disk (Figure 6-4). A sensor located at the end of the shaft monitors and maintains the rotor position between the two stators. The principle of operation is the same for both axial and radial bearings any deviation from the normal position of the rotor is communicated to the electronic control system, which adjusts the electric current going to the electromagnets to correct the rotor position. 

Temperature control of the magnetic bearing housing environment is critical to safe operation of turboexpanders. Atlas Copco-Rotoflow has developed several schemes to monitor the bearing housing temperature and maintain it at a safe level. 

Provides a purchase specification to facilitate the manufacture, procurement, installation, and testing of vibration, axial position, and bearing temperature monitoring systems for petroleum, chemical, and gas industry services. Covers the minimum requirements for monitoring radial shaft... 

When designing a system for thrust bearing proteetion, it is neeessary to monitor small ehanges in rotor axial movement equal to oil film thiekness. Probe system aeeuraey and probe mounting must be earefully analyzed to minimize temperature drift. Drift from temperature ehanges ean be unae-eeptably high. 

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