It is rather a toss-up whether to
begin with the main steam line or with feed water to the boiler.
Probably the latter is the more important as on needs to have safe and
secure means of getting water into the boiler at all times. There
should be at least two ways of getting water into the boiler when it
is under pressure.
Here we show a feed water pump operating directly from the
engine. This may be a reciprocating piston or geared pump.
As the latter is frequently unreliable, a better selection is a double
acting twin piston pump chain driven from the engine or propeller
shaft. As the feed water pump requires the engine to be turning,
it is useful to have a steam injector which can be operated at any time
there is steam up. The secret to successful injector operation is
to provide it with cool, clean water having a positive head, that is,
downhill from the freshwater tank. Steam is provided via (7),
water via (8), and the steam then delivers the water into the boiler at
(9), through check valves (X).
As backup, a hand feed water pump of a large capacity
displacement with a long handle is essential. Far too many hand
pumps installed require thousands of strokes to get a gallon of water
into the boiler when urgently needed. Water to the hand feed
water pump is controlled by (G).
Some installations may have other pressure pump selections such as
steam driven simplex, duplex water pumps, or electrically driven piston
pumps. But, whatever the choices, being able to
pressure to the boiler is mandatory!!
Boiler water level is ascertained by observing the sight gage or by
opening one of the trycocks placed in the system. One should
follow without exception the rule that when water is not clearly
visible in the sight gage, emergency procedures to add water to the
boiler and to extinguish the fire should be followed without delay!
Don't make the assumption that the water level is just
below the sight glass. If you don't see water in sight
glass, put fire out or overboard. Close draft door, open firebox door.