IMPROVEMENTS IN APPARATUS FOR SUPPLYING WATER TO STEAM BOILERS
Year: 1874

page_text: PROVISIONAL SPECIFICATION left by Robert Alexander Hunter at
the Office of the Commissioners of Patents with his Petition, on
the 8th April 1874.
I, ROBERT ALEXANDER HUNTER, of 134, Great Brunswick Street, in
the City of Dublin, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN APPARATUS FOR SUPPLYING WATER TO STEAM BOILERS,"
to be as follows:-
This Invention has for its object improvements in apparatus for
supplying water to steam boilers. For this purpose I provide a small
feed cistern which is fixed in a convenient position with its bottom a.
little above the proper level for the water in the boiler. A pipe connects
the lower part of this vessel with the boiler some distance below the
water level, and there is a valve which opens to admit water to flow from
the feed cistern into the boiler but closes when the tendency is in the
opposite direction. At the top of the feed cistern there is also a valve
opening to allow water to enter, but closing when there is pressure within
the feed cistern.

page_text: COCKS are
apparatus.
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VILL
The feed cistern having been filled with steam an injection of cold
water is admitted by automatic apparatus herein-after described, and so
a vacuum is formed which draws or allows the feed water (which may
be either hot or cold) to flow into the feed cistern. As the water rises
in the feed cistern it acts upon two ball floats, one of which opens and
· closes certain valves whilst the other serves only to lock the main float
so as to permit it to move only when the operations of filling and
emptying the feed cistern are complete. There, is a stud on the main
float which comes in contact with a disc moved by the controlling float.
The disc is cut away in parts so as to leave the main float free; when the
controlling float is at either of its extreme positions (either raised or
lowered) but at other times the main float is locked fast. Suppose then
the cistern to have filled with water and the main float to rise, in so
doing it opens a valve on a steam pipe entering the boiler (or a chamber
in free communication both at top and bottom with the boiler) just at
the proper water level, then if the boiler requires' water the lower end
of this pipe being uncovered steam from the boiler will rush up into
the feed. cistern until the pressure therein becomes equal or nearly
so to that in the boiler, and then the contents of the feed cistern will
flow by gravity into the boiler, leaving the feed cistern full of steam
at nearly boiler pressure.. At this time the main float suddenly falls
and in so doing it closes the valve against the further entry of steam
into the feed cistern, and opens another. valve which allows some of the
high-pressure steam to pass out of the feed cistern to the automatic
apparatus before referred to, which controls. the injection of cold water
and the admission of the water supply. This automatic apparatus
consists of a small chamber on the top of the feed cistern and com-
municating with it by a passage in which is the valve before mentioned
as being fitted at the top of the feed cistern. To opposite sides of the
chamber two pipes are connected to supply the injection water and the
feed water which by preference both come from tanks raised slightly
above the chamber.
*
A valve closing in the direction of the flow of the injection water
prevents its admission except when there is steam pressure in the
chamber sufficient to open the valve. There is also another valve in the
chamber which closes against the flow of the feed water, and this valve

page_text: opens as the injection valve closes, the two valves being connected
together.
When the feed cistern has emptied its contents into the boiler and the
main float falls, it opens, as already mentioned, a valve by which steam
escapes from the feed cistern; this steam enters the chamber of the
automatic apparatus and it forces the injection valve which opens
outwards from its scat. Cold water then enters the chamber and so
passes into the feed cistern, producing a partial vacuum in them.
Immediately the injection valve closes and the feed valve opens which
allows the feed cistern again to fill, this measure of water, if the boiler
requires it, is similarly discharged from the feed cistern and so on. It is
only however when the water in the boiler is below the mouth of the
steam pipe leading into the feed cistern that the charge of water is
delivered from the feed cistern into the boiler, for the descent of the
water depends on steam passing up into the feed cistern and generating
a pressure therein corresponding to that in the boiler.
When the water is high in the boiler and the mouth of the steam pipe
is covered the action of the feeding apparatus ceases.