The “Cappuccino Effect”



The “Cappuccino Effect” (also sometimes known as the “Coca Cola Effect”) essentially may be described by a frothing/bubbling effect caused by compressed air blown through the delivery hose.

The aerated bunkers when sounded will give the impression that the fuel is delivered as ordered.  In fact after some time when the entrapped air in suspension settles out of the fuel oil the oil level drops and a short fall is discovered.  In large bunker deliveries this could be considerable with huge financial implications.


What Causes the “Cappuccino Effect”?

There are several ways in which air may be introduced into fuel oil:

  1. The bunker barge may inject compressed air into its tanks prior to joint soundings being taken to increase the apparent volume of the fuel oil before it is transferred.
  2. Compressed air may be injected  into the fuel oil during the transfer, either in the vicinity of the discharge pump, or into the tank or into the discharge line.  This may be by using the compressed air equipment designed to blow through the pipelines after discharge, or via a separate system.
  3. The stripping of bunker tanks using a positive displacement pump means that air will be drawn into the fuel oil when pumped.  Consequently, excessive stripping by the bunker barge may also result in the “cappuccino effect”.

In the next technical write-up we will discuss about the signs of a Cappuccino Bunker.

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