Samson TRUCK MASTER 2500, Инструкция по эксплуатации, Страница: 17 / 36

Truck Master 2500
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3.7 Service liquid requirement
During operation it is normal that small amount of product will enter the pump, or the gas will react with
the water which becomes aggressive.
A normal recommendation is to add glycol to the water in order to protect the liquid ring pump. Glycol will
protect the pump and for example the aluminum cooler, but shall only be used in periods with temperature
below freezing point.
Due to economical aspect it is more efficient to drain the liquid separator and refill with fresh water instead
of protecting with glycol and drain the separator more rarely.
3.6 Cavitation
Vacuum 50% 75% 80% 90%
Temperature °C 80 64 59 44
Maximum discharge temperature 70 50 40 30
Note that the temperature of the gas inside the pump will heat up the water and the water surface therefore
will become a higher temperature than the measured temperature on the discharge side of the pump.
Cavitation will therefore start at a lower temperature and the maximum discharge temperature of the water
must be kept lower.
DOC1627417
DOC1627417
Below you find the boiling point of water as a function of the pressure.
When the temperature reaches the boiling point of the water, steam bobbles will be created in the liquid
ring.
These bobbles cannot exist when they enter the discharge side of the pump and therefore they will
collapse. The impact force on the surface of the rotor and flow plate will damage the pump and can lead to
a total breakdown. It is a very harmful situation that must be avoided.
It is the combination of the pressure and the temperature that will lead to the cavitation. Therefore, it is
recommended to install a cavitation valve, see illustration below that shows a clockwise rotating pump.
If counter-clockwise rotating pump, mount in opposite manifold.