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Heishin

Heishin Mohno 3-6

Name: Heishin Heishin Mohno 3-6
Brand: Heishin
SKU: OSE-77238

Heishin Heishin Mohno 3-6 — 6 bar.

Inspector Detail

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Common issues

Stator elastomer swelling or degradation from chemical incompatibility with the pumped fuel
Dry-running damage to the stator if the pump operates without adequate fluid supply
Rotor/stator interference wear reducing volumetric efficiency and achievable pressure over time
Mechanical seal or packing gland leakage at the drive shaft
Drive joint/coupling wear (progressive cavity pumps typically use a flexible joint between motor and rotor)
Cavitation-like performance loss from excessive suction lift or a clogged strainer
Pulsation or vibration from undersized suction piping or entrained air

Inspection checklist

Check for leakage at the shaft seal or packing gland
Verify no-flow/dry-run protection is functional
Check discharge pressure and flow against the pump curve for signs of stator wear
Inspect suction strainer for blockage or contamination
Check drive coupling/joint for wear, play, or unusual noise
Inspect the elastomer stator at overhaul for swelling, cracking, or abrasive wear
Check relief/bypass valve setting and function - required overpressure protection for a positive-displacement pump
Verify pump-to-motor alignment

Service intervals

Shaft seal/packing check	at routine engine room rounds; adjust or replace as needed
Stator/rotor condition check	per maker manual, commonly annually or every 4000-8000 hours depending on service duty
Relief valve function test	annually or per maker schedule
Coupling/joint inspection or lubrication	per maker manual, typically every 2000-4000 hours

Typical wear limits

Rotor/stator interference loss

condition-based - replace the stator when discharge pressure or flow falls below the required duty at rated speed, rather than at a fixed clearance figure

Ranges are typical for this design class. Always confirm against the manufacturer documentation for your serial number.

Critical spares

Stator - elastomer compound must match the pumped fuel type
Rotor
Shaft seal or packing set
Drive joint/coupling
Relief valve repair kit
Suction strainer element

Safety

Never operate a positive-displacement pump against a closed discharge valve without a functioning relief/bypass - pressure rises very quickly and can rupture piping or the pump
Fuel handling - maintain electrical bonding/grounding and control ignition sources in the pump space
Isolate and depressurize before opening the pump for maintenance

Class survey

Progressive cavity pumps in fuel oil transfer service are typically covered under general machinery/piping survey scope rather than as a dedicated statutory item. Class will expect the overpressure protection (relief/bypass valve) to be present and tested, consistent with requirements for positive-displacement pumps on the discharge side.

Estimated lifetime: Stators are the main wear/consumable item, commonly replaced every few thousand to roughly ten thousand running hours depending on duty and fluid compatibility; the pump housing and rotor typically outlast several stator changes.