Advice wanted LM30 fin
Oct 16, 2019 23:00:59 GMT
Post by Sula on Oct 16, 2019 23:00:59 GMT
In my previous post I mentioned that I had read views opposed to using an electric pump for cooling. I am unable to find again the discussion I vaguely remember. Having trawled through posts on the subject on the YBW forum, those there opposed to the idea seem only to be referring to using an electric pump for direct seawater cooling (and there were a number who had it and were content with it), so perhaps I remembered incorrectly.
One thing that was suggested on YBW, if doing a conversion to freshwater cooling, was to do a thorough descale of the engine before circulating freshwater, as the particles/debris circulating could potentially harm a circulating pump (usually a metal vaned centrifugal pump) unlike the seawater pumps (with a rubber impeller) which are designed to handle an amount of debris. I was also suggested that even after descaling it might be an idea to fit a filter before the pump.
The following data, which might be of use, are taken from the manual for the current DV36 (which is specifically advertised as a lifeboat engine so might vary a little from previous versions). The freshwater pump capacity is surprisingly high, and I have been unable to find any 12v electric circulating pumps with that sort of capacity.
COOLING WATER SYSTEM (Direct cooling)
COOLING WATER TEMPERATURE . ........................................ ......................................50 – 70oC
TYPE OF CIRCULATING PUMP / CAPACITY AT 3600 rpm...... ......................................CENTRIFUGAL / 24-30 Litres/min
COOLING WATER SYSTEM (Indirect cooling)
COOLING WATER TEMPERATURE . ........................................ ......................................70 – 95oC
TYPE OF SEAWATER PUMP / CAPACITY AT 3600 rpm .......... ......................................CENTRIFUGAL / 36-42 Litres/min
TYPE OF FRESHWATER PUMP / CAPACITY AT 3600 rpm ..... ......................................CENTRIFUGAL / 135 Litres/min
COOLING WATER CONTENT .......... ........................................ ......................................7.0 Litres
One thing that was suggested on YBW, if doing a conversion to freshwater cooling, was to do a thorough descale of the engine before circulating freshwater, as the particles/debris circulating could potentially harm a circulating pump (usually a metal vaned centrifugal pump) unlike the seawater pumps (with a rubber impeller) which are designed to handle an amount of debris. I was also suggested that even after descaling it might be an idea to fit a filter before the pump.
The following data, which might be of use, are taken from the manual for the current DV36 (which is specifically advertised as a lifeboat engine so might vary a little from previous versions). The freshwater pump capacity is surprisingly high, and I have been unable to find any 12v electric circulating pumps with that sort of capacity.
COOLING WATER SYSTEM (Direct cooling)
COOLING WATER TEMPERATURE . ........................................ ......................................50 – 70oC
TYPE OF CIRCULATING PUMP / CAPACITY AT 3600 rpm...... ......................................CENTRIFUGAL / 24-30 Litres/min
COOLING WATER SYSTEM (Indirect cooling)
COOLING WATER TEMPERATURE . ........................................ ......................................70 – 95oC
TYPE OF SEAWATER PUMP / CAPACITY AT 3600 rpm .......... ......................................CENTRIFUGAL / 36-42 Litres/min
TYPE OF FRESHWATER PUMP / CAPACITY AT 3600 rpm ..... ......................................CENTRIFUGAL / 135 Litres/min
COOLING WATER CONTENT .......... ........................................ ......................................7.0 Litres