Improvements in Steam Boilers.
Year: 1892

page_text: Date of Application, 17th Mar., 1892-Accepted, 9th July, 1892
Improvements in Steam Boilers.
I, JOSEPH EMIL PREGARDIEN of Deutz near Cologne Boiler Maker 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 improvements in the combination of a Cornish or
Lancashire boiler with a multitubular boiler for stationary purposes and for
steamers in such a manner that the fire goes first through the internal flue of the
boiler which is placed underneath the tubular part of the boiler, the heating gases
going out of the flue near the back end and passing then accross and along the
water tubes arranged in a special chamber at the top of the flue boiler, descending
at the front end to the outside of the boiler shell and being led along the lower
side of it to the chimney or they may go direct from the tube chamber into the
chimney. The water tubes are inserted into the inner sides of two water chambers
communicating with the flue boiler at the front end and at the back end at their
lower part and with an upper cylindrical vessel half filled with water and forming
a steam dome, at the top.
I carry out the new boiler in three principal manners of construction, i.e. firstly
with a single or double flue and single set or single bundle of tubes above, or
secondly with two single or double flued under boilers set side by side and being
surmounted by double sets of water tubes or thirdly with two flues, single or double
set back to back and being fired from opposite ends and having the water tubes
arranged accordingly in double sets.
The new boiler is shown on the accompanying drawings in which the figures on
Sheet one show a single flued boiler; on Sheet two a set of single flued boilers set
side by side, and the figures on Sheet three show a boiler having double flued
under boilers set back to back and a skeleton drawing of a set of such boilers set
side by side.
Figure 1 is a vertical longitudinal section of a single flued boiler;
Figure 2 is a vertical cross section of the same;
Figure 3 is a front view of this boiler;
Figure 4 is a vertical longitudinal section of two single flued boilers set side by
side;
Figure 5 shows on the left side the front view of this boiler, on the right side a
cross section of the same;
Figure 6 is a longitudinal section of two boilers set back to back;
Figure 7 is a cross section of the same;
Figure 8 a front view;
Figure 9 is a skeleton drawing of a set of 3 or 4 such boilers set side by side;
Figures 10 & 11 are respectively front views of such sets erected side by side.
Into the shell A of the lower cylindrical boiler is built the flue B, which may
be made of smooth plates or corrugated. This flue does not reach quite through
the shell, but is closed at a convenient distance from the end plate of the shell.
The heating gases are let out by side branches (one or two may be arranged) C.
Price l

page_text: At the front and back ends of the shell A water chambers D and E respectively
are connected to the same, which communicate at the top with a cylindrical drum
or vessel F serving as water chamber and steam dome or steam collector.
Between the water chambers D and E the water circulating tubes G are fixed
in a slightly oblique direction, rising towards the back end. In the middle of their
length a division wall or plate M is built in between the heating tubes G, which is
continued downwards to the horizontal center-line of the underboiler A as shown
in dotted lines in Fig. 1 and Fig. 2.
The flue boiler, as well as the heating tubes and part of the upper cylindrical
vessel are filled with water.
The current of the heating gas goes on from the fire grate I to the back of the
flue, then up through the branch pipes C up into the back part of the chamber
containing the heating pipes, accross and along between them, and over the
diaphragm M, then downwards accross and along the front part of the said chamber
and finally back along the outside of the shell A into the chimney channel K. as
indicated by arrows.
The water and the steam produced thereof make the following way: the water
is fed in at L, it rises up in the back waterchamber E into the upper vessel F and
descends in the front waterchamber D, where it enters into the circulating pipes G
to go back again into the back chamber E and completing thus its circular
current.
If it should happen that one of the circulating tubes should burst, the water
need not be drawn off and the boiler need not be stopped altogether; all what is
required is, to stop up the damaged tube.
The boiler shown in Figures 4 & 5 differs from the preceding design only by the
arrangement of two lower single flue boilers N & N₁ side by side, each one having
its separate set of heating tubes O & O¹. The back water chambers P com-
municate with the inner space of their respective underboiler N, N1, as described
before the front water chambers Q being connected to the lower boilers only by
two tubes R at each side, but sitting otherwise free upon the boiler like a saddle;
between the two water chambers are inserted the heating tubes as before and at
the top they carry the upper water and steam vessel S & S'.
This design is built for steamers; each set is therefore surmounted by a casing
and the two tube chambers are connected in front to a common funnel box T.
The way of the heating gases therefore is as indicated by the arrows; first
towards the back in the lower flue, than up accross and along the heating pipes in
each chamber and forwards to the flue box T which is common to both sets.
The water and steam make a similar course as before. The fresh water is fed
into the lower cylindrical vessel; it rises up at the back into the hind water
chamber P and thence up into the upper cylindrical vessel S & S respectively,
going down in front into the front water chamber Q whence it is led into the
heating pipes O or O' and partly back again down into the lower boiler by the
pipes R. & R', thus completing its circular current as in the preceeding case.
The front water chamber riding upon the lower cylindrical boiler like a saddle
instead of being rivetted fast to it, permits the easy expansion of the tubes O and
thus they are kept tight in the tube plates better than where they can not so easily
expand and contract themselves.
The boiler shown in Figures 6-10 is also a marine boiler. A large cylindrical
boiler shell a contains the two pairs of internal flues b, b¹ & c, c¹. These flues go
right through the whole length of the outer vessel u, but near the middle they are
stopped up by two bottoms d & e, so as to form two (four) separate flues, and the
space between the bottoms d & e is partly cut open, so as to communicate with the
water space of the vessel a.
Branch pipes & g connect the inner flues b & c to the tube chambers h & i at
the top of the boiler a. At the top of the two tube chambers is another cylindrical
vessel serving as water space and as steam dome; this drum k is connected to
the boiler a by a front and back water chamber m & n and by a larger one / at the

page_text: middle of its length in a similar way as is the case with the other designs as
described.
Between the inner tube plates of the front and back water chambers and the
two tube plates of the central one the heating tubes o & pare fixed. The long
side edges of the tube chambers are closed by plates resting upon the large vessel a
and being formed at the top into a pyramidal or conical casing serving as base for
the funnel.
The heating gases in this design of my combined boiler make the following way
through the same:
They pass along each flue from the grate towards the middle, then they rise up
through the connecting pipes f&g into the tube chambers & i, passing accross-
and along the heating tubes, baffle plates q &r compelling them to go lengthways
underneath the drum k and thence they go into the funnel.
!
The water that is fed into the large vessel a and the steam generated goes up-
through the back end and chambers m & n into the upper drum k, then down
through the central waterchamber e and into the heating tubes o & p, a trough & in
the water and steam drum k supporting and directing the current and preventing
opposite moving streams to meet and hinder each other.
The Figures 9, 10 & 11 show in outline sketches how this system of boiler is to
be erected in groups of three and four boilers side by side.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that I am aware
of the Specification of Letters Patent No. 7077 of the year 1888 granted to
Johnson Mills and do not claim anything described and claimed therein but what I
claim is :
The combination of a single or double flue boiler with an upper steam and water
drum and a set of circulating tubes between them which are fitted into the tube
plates of water chambers connecting the upper and lower cylindrical vessel or
vessels in such a manner that the water heated and steam generated in the lower
vessel (flue boiler) rises up through one of the chambers, there mixing with the
steam generated in the circulating tubes, and rising up into the upper water and
steam drum, where the steam is separated from the water whilst part of the water
in the upper drum descends through the other water chamber down into the lower
circular vessel and into the heating pipes, whereas the heating gases pass along the
internal flue to a branch pipe up into the tube chamber or chambers, and thence
accross and along the circulating tubes and along the bottom of the upper drum
and either direct into the funnel or down again and along the outside of the lower
circular vessel into the chimney.
Dated this 24th day of February 1809
J. E. PRÉGARDIEN,
Per Karl S. Mayer,
Agent.