Marine pumps: how to overhaul and identify problems

To keep proper maintenance of any machinery onboard ship, you must learn how to handle them. Improper handling of machinery reduces its durability.

Having been onboard in several occasions even as an engine cadet, I have acquired more practical knowledge on both marine auxiliaries and main propulsion system.

It’s very important as a cadet to gain good theoretical knowledge of the job while in the academy. This will support your fast learning while onboard ship.

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On this article, let’s talk about basic things you should know about marine pumps in general.

Centrifugal pump

This is commonly use pump in all ships. They are installed either vertical or horizontal. The working principle is the same, but capacity is base on usage.

Having said that, here on marine and offshore insight, one of the editors has explained step by step on how to overhaul marine centrifugal pump. While overhauling, there are also things you have to check which includes;

Ball bearing: Make sure it’s in good condition, no noise, smooth running and all balls in its position.

Mechanical seals: check the contact face, spring strength, sealing O-ring and shaft screw. Mainly the contact face between the upper and lower parts, with sealing ring is very important.

Neck bush: check for wears and replace as required

Wear ring: check for wears and replace.

Impeller: it’s the main thing to inspect, as this can cause low pressure. Check for wears, blockage, and clean as required.

An impeller may get damage due to cavitation and/or corrosion.

Shaft: check for wears on all points of the above parts positions.

screw pumps

The screw pump is one of the major pump you may found onboard. It’s easy to maintain and powerful.

This type of pump is suited for a variety of applications such as; lubrication oil circulating/ transfer, fuel-injection feed or circulating, oil burners, boosting unit, hydraulics, fuel transfer, etc.

How to overhaul screw pump?

Firstly, Put off the power supply and place a notice (men at work, don’t start)

Close suction and discharge valve

Remove suction and discharge pipe flange bolts and nuts, coupling bolts to separate the motor coupling

Remove pump foundation bolts and take out pump from motor

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Remove cover both side and remove driver screw and driven screw with bearing, bushes and seal

Inspect all parts and renew if required.

Clean all parts and assemble back. Before starting, make sure the pump turns freely, to avoid damages.

More update will be added on the post. If you have any question, ask on the comment box below.

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