Roller Mill Maintenance Maintenance on Kiln Systems Maintenance on Tube Mills Leakages at bearing housing at inspection cover at housing flanges between seal and side wall of casing between slide ring and seal lips
Service Forum Ha Noi Vietnam (Oct 2010) Preventive maintenance of plant key components Senior Service Engineer Udo Feldotto Polysius Anlagenservice Contents: - Roller Mill Maintenance - Maintenance on Kiln Systems - Maintenance on Tube Mills Roller Mill Maintenance Subjects • Roller pair • Grinding table • Tie rods and hydraulic system Titel des Vortrags Titel der Schulung Datum und Ort Polysius Roller Mill Maintenance Roller pair Bearing assembly for rollers Precondition for attaining an acceptable service life of the bearing arrangement: - correct assembly of antifriction bearing arrangement (in compliance with the Polysius assembly instructions) X The tapered roller bearing must be assembled with the roller body on the auxiliary device without intermediate ring The dimension X has to be determined The length L of the intermediate ring is calculated as follows: L = X - Z Z is normally 0.1 mm (Follow the instructions in the machine manual) Titel des Vortrags Titel der Schulung Datum und Ort Polysius Roller Mill Maintenance Roller pair Confining air system P The confining air fan generates an increased air pressure in the area of the shaft seal (roller carrier) The increased air pressure prevents the ingress of dust in the seal area and thus in the area of the bearing Correct functioning and perfect technical condition of the fan and the piping must be ensured Titel des Vortrags Titel der Schulung Datum und Ort Polysius Roller Mill Maintenance Roller pair Confining air system Confining air fan in very bad condition - The suction filters must be free of damage - The suction filters must be regularly cleaned and exchanged - The exchange interval depends on the dust formation in the building Titel des Vortrags Titel der Schulung Datum und Ort Polysius Roller Mill Maintenance Roller pair Confining air system rotating Titel des Vortrags Titel der Schulung Datum und Ort stationary Positive air pressure prevents the ingress of dust Polysius Roller Mill Maintenance Roller pair Oil circulation Circulating oil system lubrication Titel des Vortrags Titel der Schulung Datum und Ort Polysius Roller Mill Maintenance Roller pair Circulating-oil lubrication Particle filtration Indication of filter contamination via differential pressure indication Metal detector Permanent magnet (adhesion of metal particles) Indication of adhesion of metal particles Circulating-oil lubrication is recommended for achieving optimum cleaning of the bearing lubricant Titel des Vortrags Titel der Schulung Datum und Ort Polysius Roller Mill Maintenance Roller pair Guide pin Guide bracket Wear at the guide brackets and guide pins can lead to vibrations and increased wear at the sides of the grinding table liner segments and the grinding rollers Titel des Vortrags Titel der Schulung Datum und Ort Polysius Roller Mill Maintenance Roller pair mm 10 mm mm The gap between the guide pin and the guide brackets has to be checked The gap depends on the size of the mill Size (examples): RMK 27/13; gap: mm RM 57/28; gap: 10 mm Guide pin Gap increases > mm must be compensated by underlaying the wear segments with compensating plates Titel des Vortrags Titel der Schulung Datum und Ort 10 Polysius Maintenance of kiln bearing assemblies Kiln supporting rollers Inspection period and details Shutdown - Change of lubricant - Function test of circulation pump - Detailed check of roller shaft - Shaft seals have to be checked - Check of bearing clearance (radial) compare to new conditions total clearance 0,4% of shaft diameter (Example: Shaft Ø 550 mm, clearance total 2,2 mm) - Check of axial clearance (Thrust plate) Clearance > 15 mm has to be corrected Set points of bearing temperature - Alarm 60° C - Kiln shutdown 65°C Titel des Vortrags Titel der Schulung Datum und Ort 46 Polysius Maintenance on tube mills New Tube mill (Cement plant) Titel des Vortrags Titel der Schulung Datum und Ort 47 Polysius Maintenance on tube mills New Tube mill (Cement plant) Titel des Vortrags Titel der Schulung Datum und Ort 48 Polysius Maintenance on tube mills Tube mill in serious conditions (Cement plant) Titel des Vortrags Titel der Schulung Datum und Ort 49 Polysius Maintenance on tube mills Picture of the same tube mill After a big mill rehabilitation, the maintenance on the plant was completely revised The pictures were made 1/2 year after rehabilitation (Cement plant) Titel des Vortrags Titel der Schulung Datum und Ort 50 Polysius Maintenance on tube mills Lubrication unit: Subject “Filter System” • Filtering ensures wear on bearings, slide rings, internal parts of Combiflex and girth gear • Independent how often filter blockages will appear Mill operation without filter cartridges is the death of the bearing system and Combiflex gear unit • When filter blockages are increasing mostly dust/slurry contamination of the bearing housing is growing Primary activities are required • Localising of dust/slurry penetration • Replacement of housing seal if necessary • Improving the cleanness inside the mill building • Cleaning of bearing housing and lubrication tank • Oil changing Titel des Vortrags Titel der Schulung Datum und Ort 51 Polysius Maintenance on tube mills Lubrication unit: Subject “Filter System” - Sufficient filtering is the key for trouble free operation of bearing system and Combiflex system - Clean lubricant at bearing system avoids wear on slide shoe bearing and slide ring - Excellent spray view, clean oil full spray angle no blockages Titel des Vortrags Titel der Schulung Datum und Ort 52 Polysius Maintenance on tube mills Lubrication unit: Subject “Filter System” • When the contamination signal appears it is strictly recommend to replace the clogged filter element • The delta pressure steps quickly up, the increased pressure in front of filter is powerful enough to destroy the filter cartridge • Consequence bypassing of oil flow, high risk by entering of foreign particle into the lube system Titel des Vortrags Titel der Schulung Datum und Ort 53 Polysius Maintenance on tube mills Lubrication unit: Subject “Filter System” Consequence operation with collapsed filter elements and or operation without filter elements - Contaminated lubricant - Blocked spray nozzles of Combiflex (Defects on gears and bearings) - Wear on slide bearings and slide ring Titel des Vortrags Titel der Schulung Datum und Ort 54 Polysius Maintenance on tube mills Lubrication unit: Subject “Filter System” Cleaning procedure for clogged filter elements - To remove the oil, the filter cartridges must be cleaned with petroleum ether - The petroleum ether must be removed from the filter mesh by using compressed-air - Subsequently the filter cartridge has to be cleaned with a highpressure cleaner (Kärcher) for at least to 10 minutes: blowing first from the inside to the outside After that, the cleaning the cartridge from outside -The water must be removed from the filter mesh by compressed air - Visual control must be performed The filter cartridge must be inspected in day light The day light must shine through the filter mesh When this is not the case, the filter cartridge cleaning procedure must be repeated Titel des Vortrags Titel der Schulung Datum und Ort 55 Polysius Maintenance on tube mills Lubrication unit: Subject “Filter System” Maintaining of lubricant by fine filtering unit is highlighted for lube systems Advantage of an Oil Purifier - No filter elements in use - Removal of water contents - Fine filtering 2mm it is almost impossible to achieve sealed condition - Refurbishment by grinding to eliminate the uneven and rough surface is possible Titel des Vortrags Titel der Schulung Datum und Ort 61 Polysius Titel des Vortrags Titel der Schulung Datum und Ort 67 Polysius