Air Injection at Pump Suction Reduces Noise

• The first problem is that pumps for liquids are not designed to pump air and doing so may shorten the pump life. If the standby pump is unserviceable then the installation is one failure away from going out of business.
• The second problem is that the fluid arriving at the destination will have air in it and this may or may not be an issue at the destination. Frothing may be an issue. Spraying acid around with expanding air bubbles there may be another. Also, delivery flowrates will be below design values, meaning that fluids are going to take longer to arrive, which may or may not be an economic problem.
• The third problem is that the pipework upstream of the pump and the pump inlet connection may or may not have been designed to withstand the 7 bar potential from the air line. If some nutter inadvertently opens the valve fully, there is the prospect of pipes containing acid bursting and flying in all directions, invoking a measure of unpopularity with the facility's personal accident indemnity insurance provider.
• The fourth problem is that the equipment upstream of the pump may or may not be able to withstand the possibility of 7 bar compressed air spraying acid into it, and may not be rated for the full 7 bar pressure. There is, therefore, the prospect of a catastrophic equipment failure.
• The fifth problem is that in the event of an air failure, there is the possibility of acid entering the compressed air system, which might find its way to doing untold damage there, thereby invoking a measure of unpopularity among maintenance personnel and having a reach up to and including the facility's Directors.

If the pump has been cavitating before the air was introduced then there is a basic flaw in the system design, or the pump selection, or a blockage upstream, or a partly- or fully-closed valve upstream, or any combination thereof.

So:

• priority 1: double-check upstream of the remaining serviceable pump for partly-closed valves and blockages, and have the obstructions to flow removed. Disconnect the air line and run without it.
• priority 2: get the standby pump back into good repair and serviceable, for that is its design role as the business depends upon its being so.
• priority 3: have the piping layout re-assessed by a specialist Piping Designer because it is one failure away either from an injury incident due to catastrophic equipment failure or from going out of business due to a (non-)catastrophic equipment failure.

In the absence of any of the above priorities being actioned:

• Please ensure no other CR4 reader is in the area before continuing.
• Ensure that all Professional Indemnity Insurance premium payments are up to date, for it will be needed.
• Report to the local Human Resources representative and invite that individual to find someone else do the <...shift engineer...> job role.
• Prepare a fresh CV/Resume as that document will prove to be of value very shortly.

_{BTW, the <...viola...> is a musical instrument a little larger than a violin. The French word is 'Voila', with an acute accent over the 'a' that this keyboard cannot create, meaning loosely, "look at that - there it is in front of you", or something similar.}

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