Apparatus for Steam Boilers.
Year: 1884

page_text: Apparatus for Steam Boilers.
"
I THOMAS RICHARD SHILLITO of 89 Chancery Lane in the County of Middlesex,
Engineer do hereby declare the nature of the said invention for "IMPROVEMENTS
IN AUTOMATIC SAFETY APPARATUS FOR STEAM BOILERS a communication to
me from abroad by Joseph Roebruck of Aachen in the German empire, to be
as follows:-
The apparatus consists of a pipe leading from the lowest permissible water level..
upwards through the top of the boiler to a casing in which are arranged contact
pieces of an electric circuit. The upper part of the pipe is provided with a fusible
plug which hermetically seals it. Passing vertically through the fusible plug and
fixed therein is a wire, to the lower end of which a weight is suspended, and from
its upper end a cord or other suitable attachment is carried up into the casing and
attached the the upper one of the two contact pieces.
A second fusible plug is fixed in the periphery of the casing. From this plug is
led a chain which at its other end is connected to the door for admission of air to
the furnace, to the damper in the flue and to a girder which carries the ends of the
grate bars at the back of the furnace.
When the water in the boiler falls below the lowest permissible water level
steam enters the pipe leading upwards therefrom, the fusible plug which seals the
pipe is thereby melted, thus releasing the wire and allowing the weight to fall by
reason of its gravity, the two contact pieces are thus brought together and complete
an electric circuit in which is interposed a suitable form of electric signal, thereby
causing signal stations to come into operation and indicate the danger that has
arisen. At the same time (or nearly so) the fusible plug in the periphery of the
casing also melts and releases the chain and consequently thereon, the air door, and
damper in the flue are brought into the closed position, and the girder which
carries the ends of the fire bars tilted so as to cause the grate bars to fall down and
the fire to fall into the ash pit. The casing is provided with orifices for the escape
of steam, and with partitions to prevent its diffusion upwards.

page_text: Improтошед
LOW
апа пiц товщо балову
Apparatus for Steam Boilers.
I, THOMAS RICHARD SHILLITO of 89 Chancery Lane in the County of Middlesex,
Engineer, do hereby declare the nature of said invention for "IMPROVEMENTS IN
LOW WATER SAFETY APPARATUS FOR STEAM BOILERS," a communication to me
from abroad by Joseph Roebruck of Aachen in the German Empire, and in what
manner the same is to be performed, to be particularly described and ascertained in
and by the following statement :-
This invention relates to devices by means of which, when the height of the
water in a steam boiler has fallen below the lowest permissible water level or when
an excessive steam pressure is present therein, the fire under the boiler is put out
and an electrical signalling apparatus set in action so as to announce that danger
has arisen.
Referring to the accompanying sheet of drawings:
Fig. 1 is a longitudinal view of a boiler to which this invention is applied.
Fig. 2 is a vertical section of a pipe and casing mounted on the top of the
boiler, and containing a portion of the apparatus.
:
Figs. 3. and 4. are horizontal sections taken respectively through lines A B
and C D of Fig. 2.
Fig. 5 is an elevation of the said pipe and casing.
Figs. 6 and 7 shew an arrangement for setting the apparatus in action when
there is too great a pressure in the boiler.
Fig. 8 shews the fire door and fire grate in the accustomed positions and Fig. 9
the same after the apparatus has been set in action.
Fig. 10 is a modification of the arrangement shewn in Figs. 8 and 9.
Figs. 11 and 12 are respectively vertical and horizontal sections through the
boiler flue shewing the manner of mounting the damper therein.
The apparatus consists of a pipe A leading from the lowest permissible water
level upwards through the top of the boiler to a casing B in which are arranged
contact pieces F of an electric circuit. The upper part of the pipe A is provided
with a fusible plug C which hermetically seals it. Passing vertically through the
fusible plug C and fixed therein by casting or otherwise is a wire, to the lower end
of which a weight D is suspended, and from its upper end a cord E or other
suitable attachment is carried up into the casing B and connected with the contact
pieces F where it is connected to an electric conductor, this latter leading to an
ordinary electrical signalling apparatus. A second fusible plug H is fixed in the
periphery of the casing B. From this plug is led a chain I which at its other end
is connected to the damper L in the boiler Hue, to the fire door, and to a bearer 811
which carries the ends of the grate bars at the back end of the furnace, the
connection between the chain I and bearer 8¹¹ being effected through the bell crank
lever m and rods 8 and 8¹.
:
So long as the chain I retains its hold of the fusible plug H the position of this
portion of the apparatus will be that shewn in Fig. 8, that is, the normal position,
but as soon as the chain I is released the weight K operates so as to bring the
position to that shewn in Fig. 9,
By the method shown in Fig. 10 a chain or line M is connected to a bolt N.
When the weight K moves down the bolt N is drawn open. N is weighted by &

page_text: second weight P which upon the bolt N being drawn open turns upon the joint
pin R and by this movement acting on the rods 8, 8' and grate bearer 8" the fire
grate T and fire door u are caused to fall down.
The operation of the apparatus is as follows:
When the water in the boiler has fallen below the lowest permissible water level
steam enters the pipe A at the bottom and passing upwards melts the fusible
plug C, in consequence of which the wire in the same is released, allowing the
weight D to fall down and draw the contact pieces F together so that the electric
signalling apparatus in connection therewith is set in action. At the same time or
nearly so the steam will have penetrated to and melted the fusible plug H thus
releasing the chain I, upon which the weight K falls and closes the damper, the fire
door is opened and the bearer which carries the ends of the fire bars tilted so as to
cause the grate bars to fall down and the fire to fall into the ash pit. The casing B
is provided with orifices x and partitions y respectively for the escape of steam and
to prevent its ascent into the upper part of the casing, in some cases however such
orifices and partitions may be unnecessary.
Instead of fusible plug H as shewn in Fig. 2 the modification of the same shewn
in Fige. 6 and 7 may be employed. Here a special vessel G in which the fusible
plug H is fixed is connected to the casing B so as to be in communication there-
with. Instead also of the chain I being connected to several of the fittings it may
be connected or led to the damper only, from which the other fittings may be
actuated.
For the purpose, in addition to the foregoing, of guarding against the danger
arising from an excessive pressure of steam within the boiler the apparatus is
modified as shewn in Figs. 6 and 7. In addition to the parts A, B, C, D, etcetera,
as before described a pipe x passes upwards out of the boiler and communicates
with the interior of the casing B at a part shut off or enclosed by means of the
valve which is kept pressed on its seating by a strong spring w the force
of which may be regulated by the screw z to the pressure to be maintained in the
boiler, and when this is exceeded the valve v is lifted, the steam passes through
the pipe y to the fusible plugs C and H when the action and result is similar to
that hereinbefore described.
Having now particularly described and ascertained the nature of said inven-
tion and in what manner the same is to be performed I declare that what
I claim is
1. An automatic safety apparatus for the prevention of steam boiler explosions
from an insufficiency in the supply of water thereto by means of electric signalling
mechanism set in action by the melting of a fusible plug and of mechanism
independent of the electric signalling mechanism which is set in action simul-
taneously therewith and in such manner that by the melting of a fusible plug the
damper is closed, the fire door opened and the fire grate let down, substantially as
described and shewn.
2. An automatic safety apparatus for the prevention of steam boiler explosions
from excessive pressure within the boiler consisting of a combination of the
apparatus set out in claim 1 with the pipe c¹, valve mechanism v, w, 2, and
pipe y by means of which steam may pass from the boiler and melt the fusible
plugs C and H and thus set the apparatus in action as indicated in claim 1,
substantially as described and shewn."