Mody Pumps G 504 T - Manual (Page 6)

THE SEAL CHAMBER
THE HEART OF THE MODY PUMP. DUAL MECHANICAL, TUNGSTEN CARBIDE V/S TUNGSTEN
CARBIDE SEAL FACES(LOWER SEAL) AND TUNGSTEN CARBIDE V/S TUNGSTEN CARBIDE (UPPER
SEAL),SECONDARY SEALS OF HNBR RUBBER AND METAL PARTS IN STAINLESS STEEL,
RUNNING IN AN OIL BATH, ENCLOSED IN A PRESSURE COMPENSATING RUBBER OIL BAG
-CREATES THE ULTIMATE SEAL SOLUTION. THE DESIGN OPTIMIZES SEAL LIFE AND ALLOWS
FOR SIX MONTHLY(2500 HOURS)SERVICE INTERVALS.
BEARINGS.
SINGLE ROW DEEP GROOVE BALL BEARINGS SEALED FOR LIFE WITH A SPECIAL HIGH
TEMPERATURE BEARING GREASE REQUIRING NO PERIODIC MAINTENANCE WHATSOEVER.
THE HYDRAULIC ELEMENTS .
THE STAINLESS STEEL IMPELLER RUNNING AGAINST A RUBBER LINED DIFFUSER AND WEAR
PLATE, CONSTITUTE THE HYDRAULIC ELEMENTS OF THE PUMP. THE IMPELLER/DIFFUSER CAN
BE ADJUSTED TO MAINTAIN MAXIMUM OUTPUT AFTER USAGE WITHOUT PARTS REPLACEMENT.
IT IS IMPORTANT, HOWEVER, TO MAINTAIN CLEARANCES BETWEEN THE WEAR PARTS.
CABLE GLAND ASSEMBLY.(REFER DRG.)
THE PUMP IS SUPPLIED WITH 50 FEET CABLE AS STANDARD. THE CABLE IS A 4 CORE EPR
SHEATHED AND INSULATED CABLE CONFORMING TO INTERNATIONAL STANDARDS. THE CABLE
IS WATERPROOF AND CAN BE COMPLETELY SUBMERGED IN WATER. THE CABLE IS TERMINATED
IN THE PUMP AT THE CABLE GLAND. THE GLAND ASSEMBLY SEALS THE CABLE ON THE
OUTSIDE SHEATH AS WELL AS A WATER DAM ARRANGEMENT IS PROVIDED WHICH SEALS THE
INDIVIDUAL CORES OF THE CABLE. THIS FEATURE IS UNIQUE AND IS ESSENTIAL TO
PREVENT WATER SEEPING THROUGH THE CORES OF THE CABLE INTO THE CONTACTOR CHAMBER
IN THE EVENT OF A CUT CABLE. THE CABLE IS ALSO SHEATHED FOR THE FIRST ONE METER
BY MEANS OF A CABLE GRIP MADE OF STAINLESS STEEL. THIS IS ESSENTIAL TO ENSURE
THAT THERE IS NO UNDUE STRAIN ON THE CABLE IF THE PUMP IS PULLED OR LOWERED
INADVERTENTLY BY MEANS OF THE CABLE. COMPLETE DETAILS OF THE CABLE GLAND
ASSEMBLY ARE SHOWN IN THE DRAWING.
GALVANIC CORROSION PROTECTION (FOR SEA-WATER DUTY PUMPS ONLY)
THE PARTS OF THE "MODY" SUBMERSIBLE PUMP THAT ARE IN CONTACT WITH SEA- WATER
ARE PRIMARILY OF STAINLESS STEEL AND ALUMINUM. AS SEA-WATER IS AN ELECTROLYTE
THE PROBLEM OF GALVANIC CORROSION EXISTS DUE TO THE DIFFERENT ELECTRIC
POTENTIALS OF THE MATERIALS IN FLOWING SEA-WATER. TO PREVENT THIS, THE PUMPS
ARE EQUIPPED WITH ZINC ANODES FIXED ON THE OUTER CASING AND DIFFUSER. ZINC,
BEING THIS LESS "NOBLE" METAL(MORE NEGATIVE POTENTIAL)GETS CORRODED THUS
PREVENTING CORROSION OF ALUMINUM AND STEEL. IT IS HOWEVER NECESSARY TO INSPECT
THE CONDITION OF THE REPLACEABLE ANODES PERIODICALLY AND REPLACE WHENEVER
NECESSARY.(INSPECTION ONCE IN A YEAR IS ENOUGH.)
NON REPAIRABLE ITEMS
1. ALL "O" RINGS TO BE REPLACED WHENEVER PARTS ARE DISMANTLED.
2. SEAL ELASTOMER PARTS SHOULD NEVER BE RE-USED AFTER DIS-ASSEMBLY.
3. DO NOT REFILL BEARING GREASE. ALWAYS REPLACE COMPLETE NEW BEARING WITH
SPECIAL HIGH TEMPERATURE GREASE.