IMPROVEMENTS IN APPARATUS FOR PREVENTING EXPLOSIONS OF STEAM BOILERS
Year: 1858

page_text: LETTERS PATENT to Thomas Archer, junior, of Dunston, near Gateshead,
for the Invention of "IMPROVEMENTS IN APPARATUS FOR PREVENTING
EXPLOSIONS OF STEAM BOILERS."
Sealed the 1st April 1859, and dated the 14th October 1858.
PROVISIONAL SPECIFICATION left by the said Thomas Archer at the
Office of the Commissioners of Patents, with his Petition, on the
14th October 1858.
I, THOMAS ARCHER, junior, of Dunston, near Gateshead, do hereby declare
the nature of the Invention for "IMPROVEMENTS IN APPARATUS FOR PREVENTING
EXPLOSIONS OF STEAM BOILERS," to be as follows:-
This Invention has for its object improvements in apparatus for preventing
explosions of steam boilers. For this purpose the safety valve is enclosed in a
case, through the top of which there is an opening through which the rod of
the safety valve passes, and through which steam passes from the boiler when
the safety valve is somewhat raised. On the rod of the safety valve there is
another valve, which, when the safety valve is raised beyond a certain point,
closes the opening in the top of the case, and causes the steam to pass through
a pipe which leads from the case to the interior of the furnace of the boiler,
and so damp the fire, and reduce the pressure in the boiler. Steam is also
caused to pass on to the fuel in the furnace when the water in the boiler gets
too low, by means of a float in the boiler, to which a rod is attached, which
passes through a stuffing box in the top of the boiler, this rod passes through
a hole in a prolongation of the lever (to which a weight is attached), which

page_text: keeps down the safety valve, and on the end of the rod there is an
enlargement which cannot pass through the hole in the lever. By this means
when the water in the boiler gets too low, the weight of the float depresses
the arm of the lever through which the rod passes, lifts the arm of the lever
which keeps down the safety valve, and allows the steam to pass on to the fuel
in the furnace.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Thomas Archer in the Great Seal Patent Office on the 14th
April 1859.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
ARCHER, junior, of Dunston, near Gateshead, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fourteenth day of October, in the year of our
Lord One thousand eight hundred and fifty-eight, in the twenty-second year
of Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Thomas Archer, Her special licence that I, the said Thomas
Archer, my executors, administrators, and assigns, or such others as I, the
said Thomas Archer, 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, use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for "IM-
PROVEMENTS IN APPARATUS FOR PREVENTING EXPLOSIONS OF STEAM BOILERS," upon
the condition (amongst others) that I, the said Thomas Archer, my executors
or administrators, by an instrument in writing 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 Thomas Archer, do hereby declare the
nature of the said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement thereof, that is to say:-
This Invention has for its object improvements in apparatus for preventing
explosions of steam boilers; for this purpose, the safety valve is enclosed in a

page_text: Figure 1, Sheet I., is a longitudinal section of the apparatus, shewing its
application to an ordinary cylindrical boiler, and Figure 2 is an end elevation
of valve and transverse section of the boiler.
In the cast-iron case A, fixed on the top of the boiler, is placed a brass
double-faced conical valve B, with its valve seats C and D, also of brass.
This valve is connected by a double eye to the wrought-iron lever E, this
lever is loaded at one end by the weight F, and has at its other extremity a
slotted eye, through which the whistle tube moves freely up and down; G is
a cast-iron float to which is attached on the top side, the top float rod H,
the tube I, and the whistle J, this whistle serves to announce when the water
is falling too low, as is herein-after explained, and also if the water continues to
fall, to raise the valve B, by coming in contact with the lever E. On the
bottom of the float, there is a rod K, called the bottom float rod; this bottom
float rod works freely in a wrought-iron guide L, so as to prevent the top float
rod or whistle tube from being bent by the motion of the float in the water.
Figure 1, Sheet 2, is a plan of the case A, and valve B; Figure 2 a section
of the same parts; Figure 3 a plan of the float; Figure 4 a side elevation of

page_text: the same; Figures 5 and 6, elevations of valve weight; Figures 7 and 8,
plan and section of packing weight; Figures 9 and 10, elevations of fulcrum ;
Figures 11 and 12, elevations of guide; Figures 13 and 4, elevations of
double eye; Figure 15, section of whistle, whistle tube, and top float rod;
Figure 16, valve lever; Figure 17, bottom float rod.
I will now proceed to describe the working of the apparatus. Supposing the
water level in the boiler to fall below its proper level, the float G, Sheet 1, will
fall with it until the hole a, Sheet 1, in the whistle tube I, comes within the
boiler, when the steam will rush up the whistle tube I, and blow the whistle
J, to call the attention of the person in charge, but if this is not attended to,
and the water level is allowed to fall still further, the whistle comes gradually
down, (still giving the alarm,) until it rests on the lever, the weight of the
float G, hanging on the lever, together with the pressure of the steam on the
under side of the valve B, overcomes the weight F, and the valve B, is raised
so as to allow the steam to blow into the air through the apertures made for
the purpose in the top valve seat C; if the water is allowed to get still lower
the valve B, is raised so as to shut against the top seat C, the blow off steam
is then conducted through the pipe b, (Figure 1, Sheet 2,) on to the fire, so as
to extinguish it, this pipe b, has its junction with the valve case between the
upper and lower valve seats. Supposing the pressure of the steam to be too
great, the water being at its proper level, the result will be the same, for the
pressure of the steam inside the boiler being greater than the load on the
valve, will raise the latter and allow the steam to escape through the openings
in the seat C, or if the pressure becomes excessive, will close the valve B
against the seat C, and the steam will pass through the pipe b, (Figure 1,
Sheet 2,) and damp or extinguish the fire, as before described.
In witness whereof, I, the said Thomas Archer, have hereunto set my
hand and seal, this Eleventh day of April, in the year of our Lord
One thousand eight hundred and fifty-nine.
Witness,
JOHN BLENKINSOP, Agent.
Dunston,
Gateshead.
THOMAS ARCHER, JUNR. (L.S.)