IMPROVEMENTS IN HIGH AND LOW WATER LEVEL INDICATORS FOR STEAM BOILERS
Year: 1869

page_text: PROVISIONAL SPECIFICATION left by Alexander Melville Clark at
the Office of the Commissioners of Patents, with his Petition, on
the 9th October 1869.-A communication from abroad by Gideon
Blackburn Massey, of the City, County, and State of New York,
United States of America.
I, ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County
of Middlesex, Patent Agent, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN HIGH AND LOW WATER LEVEL INDICATORS FOR
STEAM BOILERS," to be as follows :—
This Invention relates to a new alarm attachment to steam boilers
which will be operated when the water is a certain distance above as
well as when it is below the proper height, and which will also when it
is operated indicate whether it is put in action by high or low water.
The engineer is thereby enabled at once to apply the proper remedy, and
either to arrest the supply of water or to provide for a further supply.
This Invention is illustrated in the accompanying Drawings, Figure 1
showing a central vertical section of the apparatus.

page_text: A represents a cylindrical vessel of suitable size attached to a tubular
stem B which projects from the boiler C, and which extends into said
boiler as far as to the low water line of the same. Upon the cylinder A
is placed a whistle D, as shown. Within the vessel A is a hollow vessel
or float E, which has a pipe F extending into the pipe B and as far as the
same, as shown. Into the pipe F is fitted a still smaller pipe G, which
extends into the float E entirely or nearly to the upper end of the same,
its upper part being perforated, as shown. The lower end of the pipe G
extends entirely through the pipe F, and is then bent up to reach to the
high water line. H is a valve fitted upon the float E to keep the whistle
closed. When the water is at its proper level, as in the Drawing, it will
by the pressure be caused to rise in the pipe B and vessel A, as indicated.
The steam enters the upper end of the pipe G, and is thereby carried
into the float, filling the same and the pipe F to the regular water height.
The vessel E floats therefore on the water in A and is elevated to hold
the valve H against its seat. When the water falls below the lower ends
of Band F it will also flow out of the vessel A. and the float will cease
to swim; it will then drop upon the bottom of A and draw the valve
down, thereby allowing the steam to pass through and blow the whistle.
When the water rises above the turned up lower end of the pipe G
steam will be displaced in the float by water passing up through the
pipes and G, and the float will thereby become heavy and will sink
in A to open the valve. The water in A will then be blown through the
whistle. Thus at low water steam and at high water water will be
blown through the whistle. The steam as it enters the float during the
normal water height will condense there and flow back into the boiler
through the pipe F, and a continuous circulation is thus maintained.
In Figures 2 and 3 this arrangement is modified so as to somewhat
simplify it and adapt it to act only as a low water detector.
A in the Drawing represents a portion of a steam boiler. Into the boiler
is fitted a preferably vertical pipe B whose lower end is about on a level
with the low water line, that is to say, with the line below which the water
should not stand in the boiler. The pipe is open at its
above the boiler fitted into the lower end of a vessel C.
lower end and is
This vessel is of
cylindrical or other suitable shape and supports a steam whistle D on
its upper head. The entrance to the steam whistle is to be closed by a
-valve E which is fitted upon a cylinder or other vessel F. The cylinder F
is enclosed within the vessel C and is smaller than the same, so that it

page_text: can play up and down therein, and has an annular steam passage a
formed around it. Lateral play of the vessel F is or may be prevented
by arranging projecting ribs or lugs 6 on its sides. When the water in
the boiler stands higher than the lower end of the pipe B it will by the
pressure within the boiler be forced into the pipe B and vessel C to elevate
the vessel F, which will float on the water and thereby hold the valve E
against its seat as in Figure 1. The valve will thus close the passage c
to the steam whistle. As soon however as the water falls below the
lower end of the pipe B it escapes from the vessel C and steam enters
the same.
The vessel F will not float on the steam but will drop so
as to draw the valve down as in Figure 3. The steam will then enter
the whistle and blow the alarm. The valve in order to always fit into
the seat at high water (even if the vessel should be slightly displaced
in a horizontal direction) is swivelled in the vessel F with its shank d
and has a ball e at the lower end of the shank so that it may swing
in either direction. The vessel F may therefore move slightly in a
horizontal direction when the valve is shut without drawing it out of
its seat.