IMPROVEMENTS IN WATER LEVEL INDICATING AND LOW WATER ALARUM APPARATUS FOR STEAM BOILERS."
Year: 1875

page_text: LETTERS PATENT to Martyn Jolin Roberts, of the City of Bath,
Esquire, for the Invention of "IMPROVEMENTS IN WATER LEVEL
INDICATING AND LOW WATER ALARUM APPARATUS FOR STEAM BOILERS."
PROVISIONAL SPECIFICATION left by the said Martyn John Roberts
at the Office of the Commissioners of Patents, with his Petition,
on the 24th July 1875.
I, MARTYN JOHN ROBERTS, of the City of Bath, Esquire, do hereby
declare the nature of tho said Invention for "IMPROVEMENTS IN WATER
LEVEL INDICATING and Low Water Alarum Apparatus for Steam BOILERS," to
be as follows:-
My.Invention has reference to apparatus for indicating the water
level in steam boilers, and to apparatus for giving an alarm in case the
water level becomes too low.
For the purpose of indicating the water level I place a pipe in
connection with the boiler so that the water level is the same in both,

page_text: and I indicate the gradual rise or fall of the water level by the torsion of
a flexible tube placed in the pipe, which flexible tube is actuated by a
rod within it connected to a float on the water. On the outer part of the
tube is an index. When the flexible tube is of a material likely to be
broken by the pressure of the water and steam within it, I encircle it
with metal or other suitable strong material, either in one piece or in
sections, and I also by a suitable support prevent its elongation or being
blown out. And I sometimes extend the pipe below the bottom of the
boiler, so that the water therein may be cooler than that in the boiler;
the material of which the flexible tube is composed will then not get
overlicated
For the purpose of giving an alarm -in case the water gets too low I
connect a float on the water with a rocking or tipping tube, containing
the points of a wire communicating with a galvanic battery and a signal
bell This tube is closely scaled and contains a small quantity of ]
mercury, all dirt and grease being effectually excluded When the float
sinks to a given distance, owing to the water in the boiler becoming too
low, it turns the scaled tube, so that the mercury therein falls upon the
wire points and connects them metallically. The clectric current there-
foro circulates and rings the signal bell Or the points may be ?
electrically connected by a solid metallic body falling on them when the
tube is turned. Or for the purpose of giving an alarm in case the water
gets too low I employ a pipe closed at its upper end, while its lower end
communicates with the boiler at the low water level. The pressure in
the boiler will keep the pipe filled with water, but if the water in the 2
boiler gets below the level of the mouth of the pipe, then the water falls
out of the pipe and the float therem necessarily falls and turns the
rocking or tipping tube.

page_text: water in the boiler, the electric contacts for signalling low water may be
produced by the torsion of this tube, or any suitable apparatus connected
therewith.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Martyn John Roberts in the Great Seal Patent
Office on the 24th January 1876.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, MARTYN
JOHN ROBERTS, of the City of Bath, Esquire, send greeting
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-fourth day of July, in the year
of our Lord One thousand eight hundred and seventy-five, in the
thirty-ninth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said Martyn John Roberts, Her
special licence that I, the said Martyn John Roberts, my executors,
administrators, and assigns, or such others as I, the said Martyn John
Roberts, my executors, administrators, and assigns, should at any time
agree with, and no others, from time to time and at all times thereafter
during the term therein expressed, should and lawfully might make,
usc, exercise, and vend, within the United Kingdom of Great Britain
and Incland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN WATER LEVEL INDICATING AND LOW WATER ALARUM APPA-
RATUS FOR STEAM BOILERS," upon the condition (amongst others) that I,
the said Maityn John Roberts, my executors, or administrators, by
an instrument in witing under my, or their, or one of their hands.
and seals, should particularly describe and ascertain the nature of the
said Invention, and in what manner the same was to be performed,
and cause the same to be filed in the Great Seal Patent Office within
Six calendar months next and immediately after the date of the said
Letters Patent
NOW KNOW YE, that I, the said Martyn John Roberts, do hereby
declare the nature of my said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement thereof, reference being had to the accom-
panying Drawings (that is to say):-
My Invention has reference to apparatus for indicating the water

page_text: level in steam boilers, and to apparatus for giving an alarm in case the
water level becomes too low.
For the purpose of indicating the water level I place a pipe in
connection with the boiler, so that the water level is the same in both,
and I indicate the gradual rise or fall of the water level by the torsion of
a flexible tube placed in the pipe, which flexible tube is actuated by a
rod within it connected to a float on the water. On the outer part of
the tube is an index When the flexible tube is of a material likely to
be broken by the pressure of the water and steam within it, I encircle it
with metal or other suitable strong material either in one piece or in
sections, and I also by a suitable support prevent its clongation or
-being-blown out. And I sometimes extend the pipe below the bottom
of the boiler, so that the water therein may be cooler than that in-the
boiler; the material of which the flexible tube is composed will then
not get overheated.
For the purpose of giving an alarm in case the water gets too low,
I connect a float on the water with a rocking or tipping tube containing
the points of a wire communicating with a galvanic battery and a signal
bell. This tube is closely scaled and contains a small quantity of
mercury, all dirt and grease being effectually excluded. When the float
sinks to a given distance owing to the water in the boiler becoming too
low, it turns the scaled tube, so that the mercury therem falls upon the
wire points and connects them metallically The electric current there-
forc circulates and rings the signal bell, or the points may be electrically
connected by a solid metallic body falling on them when the tube is
turned. Or for the purpose of giving an alarm in case the water gets
too low, I employ a pipe closed at its upper end, while its lower end
communicates with the boiler at the low water level. The pressure in
the boiler will keep the pipe filled with water, but if the water in the
boiler gets below the level of the mouth of the pipe, then the water falls
out of the pipe, and the float therein necessarily falls and turns the
rocking or tipping tube.
When I use the rocking or tipping tube enclosing mercury I some-
times exhaust this tube of atmospheric air, or partially exhaust it, and
put hydrogen or other non-oxidising gas therein for the purpose of
preventing the oxidation of the mercury.
I sometimes also make contact between the surfaces to be electrically
connected by enclosing them in a case with flexible sides, and by

page_text: arranging the float so that when it descends to a certain level it shall
squeeze the sides together, and thus make the metallic surfaces touch
each other. Or a torsion tube may be used and the electric contacts for
signalling low water produced by the torsion of this tube or contact
maker or any suitable apparatus connected therewith, and I sometimes
cover such "contact maker" with a case to prevent injury from dirt,
each other. Or a torsion tube may be used and the elecIFIC CONTACES FOE
signalling low water produced by the torsion of this tube or contact
maker or any suitable apparatus connected therewith, and I sometimes
cover such "contact maker" with a case to prevent injury from dirt,
grease, &c.
Figure 1 of the accompanying Drawings is a vertical section of part
of a steam boiler having a water level indicating apparatus constructed
according to my Invention.
A is the boiler; B is a pipe in connection therewith, the water level
being the same in both; the pipe B is extended below the level of the
bottom of the boiler as shewn, so that the water in the lower part of the
pipe may be cooler than that in the boiler, C is a flexible tube, made by
preference of india-rubber, fixed to and communicating with the lower
part of the pipe B at its inner end, while its outer end is attached to a
plug or lump D of brass or other suitable material, E is a rod within
the tube C; this rod is fixed to the plug D and is extended beyond the
lump, and carries a hand or index F which moves over a dial F¹, G is a
stop or stay at the outer end of the rod, and the inner end of the rod is
supported by a bearing II; I is a pulley keyed on the rod E, and from
this pulley a cord K provided with a counterweight L is carried to a
float M on the surface of the water in the pipe B; N, N, are a series of
metal rings placed around the tubo C to prevent the tube being ruptured
by the pressure of the water within it As the float M falls or rises with
changes in the water level, so does the rod E turn on its axis, and as the
outer part of this rod is fixed to the outer end of the rubber tube C
through the intermediation of the plug D, it follows that a torsion to a
greater or less extent of the tube O is produced, and the index F is
moved to an extent regulated and controlled by the torsion.
It is important that the external support of the tube C should be in
the form of rings or sections N, N, as shewn, and not be a pipe or single
piece, because in the latter case the pressure of the tube against the
support would be so great as to prevent the torsion. Again, the tube C
being fixed at its inner end, the torsion gradually increases as it reaches
the outer end, and therefore the employment of the rings N is necessary
to allow of the unequal torsion,

page_text: Figure 2 is a vertical section, and Figure 3 a plan of a low water
alarum apparatus with a rocking or tipping tube in accordance with my
Invention; A is the boiler, and B, a dome or cap on the upper part of
the same; C, C, are bars at the lower part of the dome forming bearings
for a tube D made of wood or other suitable insulating material; this tube
is closely sealed, and contains a small quantity of mercury; E is a cable
or cord composed of two wires perfectly insulated from each other, and
communicating with a galvanic battery and signal bell. The cable E is
led through an aperture F in the dome B, this aperture being thoroughly
caulked The two wires are led through the end of the tube D and
terminate in platinum points, G is a rod connected to the upper end of
the tube D, and carrying at its lower end a float H which rests on the
water in the boiler; I is a counterweight to counterbalance or partly
counterbalance the weight of the rod G.
When the parts are in their normal position as shewn in the figures,
the platinum points of the two wires are not in metallic connection; but
when the water in the boiler gets too low and the float consequently
sinks it turns the tube D on its pivot, so that the mercury therein falls
upon the wire points, connects them metallically, and therefore rings the
signal bell. As before stated, a solid weight, which may be in the form
of a ball or otherwise, may be substituted for the mercury. Instead of
placing the apparatus just described into the boiler itself, it may be put
into a tube connected with the boiler, thus avoiding disturbance of the
float by any ebullition of the water within the boiler.
Figure 4 is a vertical section representing another low water alarum
apparatus constructed according to my Invention as before described;
A represents the boiler, and I, the line below which the water level
should not be allowed to get; K is a pipe communicating with the
boiler at this line and closed at its upper end. In this pipe K is a float
H connected with a tipping tube D arranged as before described. When a
the boiler is sufficiently full of water, the pressure in the boiler keeps
K filled with water, but should the water get below the line I,
the water in the pipe K falls out, the float H falls, and the tube D is
tipped so as to ring the signal bell.
the
pipe
And having now described the nature of my said Invention and in 3
what manner the same is to be performed I declare that I claim,-
Thingt Constructing water lowal indiantic