Examples Of Diaphragms Failures & Causes - Bertolini GIARDINAGGIO Serie Manual De Uso Y Mantenimiento

WARNING!
Too much oil creates pressure inside the crankcase, giving rise to possible leaks or
rupturing the diaphragms owing to overpressure.
For pump models without the oil drain plug, periodic oil changing must be carried
out when the pump components are checked for wear, we recommend at the end of
each season or after every 500 hours service.
The oil is drained out by disassembling a head and relative piston sleeve.
6.5 Examples of diaphragms failures & causes
CIRCULAR FRACTURE ON PISTON SIDE OF DIAPHRAGM
WHICH IS SAME DIAMETER AS PISTON
POSSIBLE CAUSES:
1. BLOW-BY BETWEEN PISTON AND SLEEVE
2. SUCTION HAS TOO MUCH PRESSURE (EXCESSIVE
HEAD)
3. LOW PUMP RPM
4. DELIVERY VALVE NOT SEALING
5. LOW OIL LEVEL IN PUMP
CHEMICAL INCOMPATIBLE WITH DIAPHRAGM MATERIAL
POSSIBLE CAUSES:
1. FATIGUED AND WORN UNDERNEATH PISTON
RETAINING DISC
2. DIAPHRAGM SWOLLEN AND SOFT
3. DIAPHRAGM SOFT AND SPONGY
4. INCREASE IN EXTERNAL DIAMETER
FRACTURE ON EXTERNAL DIAMETER, AND FATIGUE AND
WORN UNDERNEATH PISTON RETAINING DISC
POSSIBLE CAUSES:
1. FATIGUE BREAKAGE DIAPHRAGM WORN OUT
A STRAIGHT FRACTURE
POSSIBLE CAUSES:
1. INCORRECT AIR BLEEDING, AIR TRAPPED UNDER
DIAPHRAGM
2. BLOCKED SUCTION
TWO SMALL FRACTURES CORRESPONDING TO VALVE
POSITION
POSSIBLE CAUSES:
1. RESTRICTED SUCTION
2. PUMP RPM ABOVE SPECIFICATION
3. SUCTION VALVE NOT SEALING
4. CHEMICAL INCOMPATIBLE WITH DIAPHRAGM
MATERIAL
83