Improvements in Safety Devices for Steam Generators.
Year: 1899

page_text: Date of Application, 21st Dec., 1899-Accepted, 21st Dec., 1900
COMPLETE SPECIFICATION.
Improvements in Safety Devices for Steam Generators.
I, HERMANN SCHÜTZE, Manager of the Gas and Water-works, Bremerhaven,
in the Empire of Germany, do hereby declare the nature of this invention 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 an automatic device (which may be actuated also
by hand) for shutting off the steam in boilers in case of explosions of steam-
pipes.
By this invention a safety-device is provided serving to protect the engine-
men against scalding, in case of explosion, by the escaping steam of high tension;
the new construction being particularly suitable for marine boilers and steam-
engines.
The main feature of the invention consists in the arrangement of a receiver
on the outer (upper or lateral) boiler-shell, which may be termed an accumulator
and is filled in its normal condition with steam having the same tension as that
contained in the boiler, but which, in the case of an explosion, maintains, when
the tension in the pipe-conduit and in the boiler is suddenly reduced, its high
tension, serving to shut off the steam-conduit in the interior of the boiler by
means of a suitable device.
The new construction is illustrated in the Figures 1 to 5 of the accompanying
drawings.
As may be seen from the cross section of the boiler in Figure 1 there is
arranged in the interior of the boiler K a double-seat-check-valve v v¹, which,
when opened, admits the steam of the boiler through the openings into the
pipe conduit R to the steam conduit S leading to the engines.
Above this double-seat-check-valve there is connected or rivetted to the outer
shell of the boiler a receiver or accumulator B.
The spindle of the check-valve passes through an aperture of the boiler-
shell and through the bottom of the accumulator B into the interior of the latter.
The passage of the valve-spindle through the bottom of the accumulator is
tightened by means of a stuffing-box.
To the upper end of the spindle 2 is secured a cross bar r (Fig. 2) carrying at
both end rollers rl, engaging in two oblique slots Z provided in plates Z
which are guided between rollers m.
The ends of these two plates Z are rigidly connected with each other by a cross
bar; the left bar being connected with a piston rod and the latter with a
piston sliding in a cylinder e.
A prolongation of the piston rod 72 passes through a stuffing-box in the end
of the cylinder e, and at the outside it is provided with a handle 73.
The right-hand cross-bar of the plates is in communication with a draw-
rod 7 provided with a handle %, which rod passes through a stuffing-box in
the front wall of the accumulator B.
By means of the handles 73 and Z the plates guided between the rollers m
can be moved to-and-fro, whereby an opening and closing of the check-valve v¹

page_text: can be effected, as owing to the slot Z arranged in the plates Z the valve-spindle r²
is thereby raised or lowered.
The passing of the piston-rod 72 through the end of the cylinder e, and the
passing of the draw-rod through the opposite wall of the accumulator (the
rods having the same diameters) have however not only for their object to allow
of moving the valve by hand, but principally to cause the equilibrium, and in
consequence thereof also the working of the automatic check-device to be
ensured, at a determined difference of tension between the steam in the accumu-
lator and that in the conduit, when an explosion takes place, at a moment when
the usual working-pressure in the boiler is reduced, by contrary draughts or by
the failing of the exhausters of the chimney or by the periodical formation of
slag on the grates &c., gradually to a small number of atmospheres.
The new construction differs from these hitherto in use by the fact that it
works always at a determined difference of tension, it being immaterial whether
the working tension be high or low.
Below the cylinder e a second cylinder p is arranged which is in communica-
tion with the first cylinder e, as shown in Fig. 1.
In this cylinder p is a piston connected by a draw-rod with a perforated
piston a sliding in a cylinder a open at both ends and arranged in the accumu-
lator B. The working of this piston a¹ will be hereinafter more fully described.
As already stated above, the cylinders and are in communication with
each other. These two cylinders are connected by a conduit q q2 with the steam
collector S as illustrated in Figure 3.
If an explosion of a pipe or any other explosion occur's the pressure will be
reduced on account of the sudden violent escape of steam, first in the steam col-
lector S and then also in the steam boiler, the pressure will therefore be lower
than in the accumulator B, for the steam in the accumulator B can escape only
slowly through the small section of the boring into the interior of the boiler
so that in any case, where the cross section of the aperture suddenly
produced by the explosion is larger than the cross-section of the
boring o, a corresponding overpressure in the accumulator B is ensured. At
the same time there is a low pressure in the conduit-pipe q 72, as also in the
cylinders e and p since they are in communication with the conduit q.
In consequence thereof the pistons and are moved by the excess pressure
in the accumulator B to the left; by this motion to the left of the piston & the
valve-spindle is raised and the double valve v vl closed, and owing to the
simultaneous movement to the left of the piston ¹, the piston a', which controls,
in normal working, the communication of the steam between the interior of the
boiler and the accumulator B through its perforation and the boring o, (Fig. 4)
shuts off on one hand this communication but, on the other hand, by means of
its recess a² (Fig. 5) and the conduit pipe connected with the cylinder a, puts
the conduit g in communication with the chimney so that the steam contained
in the broken conduit is led away and rendered harmless.
If, after the damage caused by the explosion has been repaired, working
steam is to be introduced again into the collecting pipe, the steam enclosed in
the accumulator B is caused to flow through the cock q¹ into the collecting pipe,
and the double-seat valve v¹ is opened by moving the handles Z3 Z5 to the
right.
All the check devices of the boilers of a ship may be connected to the conduit g
which is filled with steam from the steam collector S, and may be separately
cut off by means of cocks. By this invention the result is obtained that in
case of an explosion all the steam-boilers of a ship can be cut off at the same
time.
In order that the steam introduced through the pipe-conduit 9 may have, in
the cylinders e and p. always the same tension as the steam in the accumu-
lator B, the steam conduit 7 is as shown in Fig. 3, in communication, by means
of a branch pipe q³ ³, with a chamber i arranged in the interior of the accumu-

page_text: lator B. This chamber is heated by the steam in the accumulator B and con-
sequently imparts heat to the steam in the conduit q, q³ communicating
with the cylinders e and p so that substantially the same pressure exists in both
the accumulator B and the cylinders e and p. The tube q communicates with
the accumulator B through a branch q having a tap q', so that the accumulator b
can be completely cut off from the pipe y when required, by closing the tap q¹.
The borings, Fig. 1, at the left hand, which are in communication
with the interior of the accumulator, serve also to heat the cylinders e and p
for maintaining the steam therein at the same tension as the steam in the accumu-
lator B.
If steam coming from the steam collector S were used without being heated
supplementarily, an exact working of the check-device would not be possible,
as the conduit q leading this steam from the steam collector S to the cylinders e
and p is exposed on its way more or less to cooling influences. In case of a
rupture of a pipe conduit the steam of the boiler is therefore cut off automatic-
ally and with certainty by the described device. In this case or at any other
moment of danger, in particular when a rupture occurs in stopping machines.
where no flow of steam takes place in the conduits and where the production of
a difference of pressure necessary for actuating the safety-device is uncertain,
the latter can be put in activity by hand from any part of the ship by cooling
the pipe conduit q to a great extent at any proper place, so that a partial con-
densation and in consequence thereof a decrease of the pressure is obtained in
the conduit q, causing thereby as above described, a closing of the check-valve
In Fig. 3 there is provided in the conduit q, at c, a loop or branching which is
enclosed in a casing. Into this casing water is introduced from any suitable water-
tank w (Fig. 3) by opening a cock h, so that the conduit can be cooled at this
point and the tension of the steam contained therein reduced. The conduits
of water leading to the cooling place of the pipe q may be arranged in severa..
parts of the ship, so that it is only necessary to open the cock h provided at the
corresponding place for putting the safety device into action.
³.
If more check-devices are used for one boiler-battery it is not necessary to
test regularly all these devices, in order to know whether the resistance in their
mechanisms has increased, it will be sufficient to examine in this respect only one
device.
For by the regular working of one device all the others connected with the
common conduit q are set to work with absolute certainty, as the steam con-
tained in the conduit q is led away by means of the piston valve a into the
chimney, so that the left hand sides of all the pistons k, Fig. 1, are completely
released and put in motion.
Having now particularly described and ascertained the nature of my said in-
vention, and in what manner the same is to be performed, I declare that what
I claim is: -
1
1. A device for shutting off automatically, in case of an explosion in the steam
pipe, the steam of a generator, characterised by the arrangement on the outer
boiler-shell of a receiver, as B, communicating with the interior of the boiler
through a small orifice and containing, during normal work steam having the
same tension as the steam in the boiler, but which, when an explosion takes
place and the tension in the pipe conduit and in the boiler becomes lowered,
maintains a higher tension which serves to close the main check-valve in such a
manner, that the valve spindle engages by means of a cross bar oblique slots in
plates guided between rollers, the said plates being connected by a rod with the
piston of a cylinder in the side of the receiver and connected with the pipe con-
duit of the steam collector whereby the piston is so displaced owing to the higher
pressure in the receiver as to close the main check valve, substantially as
described.
2. In a device of the kind described the arrangement of a lengthened piston-

page_text: rod as 72, passing through a stuffing in the front wall of the receiver into the
outer air and a draw-bar as 7+, both of the same diameter, which parts serve both
for moving the plates (Z) in order to open or to close by hand the main-valve,
and for the purpose of ensuring at a determined difference of tension between
the boiler and the steam-conduit, the equilibrium of the check-device in such
cases, when the usual working pressure in the boiler is gradually reduced,
substantially as described.
3. In a device of the kind described the arrangement of a cylinder as p,
with a piston in communication on the one hand with the receiver and on the
other hand with a conduit as q for the purpose of actuating a slide provided in
the receiver and connecting, in one position, the receiver with the interior of
the boiler (through a passage as o) and, in the other position connecting the
conduit with the chimney in such a manner that in case of an explosion the
the communication between the boiler and the receiver is automatically closed
and that between the conduit and the chimney opened substantially as described.
4. In combination with a device of the kind described the arrangement of a
heater in the receiver or accumulator for the purpose of maintaining the steam
introduced from the steam-collector into the conduit always at the tension of
the steam in the receiver in order to cause all the check-devices provided on a
series of steam-boilers to form by their connection with the common conduit
a single automatic check-device substantially as described.
5. In combination with a device of the kind described the arrangement of a
cooling device in the conduit for the purpose of shutting off simultaneously all
the steam conduits of a ship by admitting water substantially as described.
6. The complete safety device for steam generators substantially as described
or illustrated in the accompanying drawings.
1900
BOULT, WADE & KILBURN,
Agents for the Applicant.