Improvements relating to the Firing of Marine and other Boilers.
Year: 1892

page_text: COMPLETE SPECIFICATION (AMENDED).
· Improvements relating to the Firing of Marine and other Boilers.
I, RUDOLF MÜLLER of Reilerstieg Hamburgh in the Empire of Germany,
Engineer 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 which consists of improvements in the invention for which a Patent
No. 7703 A.D. 1892 was granted to me relates to the firing of boilers and more
especially of those designed to possess great heating surface together with com-
paratively small bulk and which therefore are very especially suitable for marine
TISC. The object of the invention is also to save space for the firing, where, as is
the case with boilers having the above qualities, internal firing cannot be had and
outside firing is therefore the only method obtainable, that is to say the object of
the invention is to provide grates of the requisite capacity for burning a large
quantity of coal or fuel within a smaller space than equivalent grates of the same
capacity usually require.
The invention is illustrated in the annexed drawings in which
Fig. is a cross section of a ship fitted with boilers of the type hereinafter
described and in respect of which I have made application for Letters Patent of
the same date herewith, the improved system of firing the immediate subject of the
present invention is illustrated as applied to such boilers.
Fig. 2 is an enlarged front elevation of the fire boxes, one in section, as applied
to one of said boilers with double or twin firing.
Fig. 3 is a longitudinal section through the boiler and one of the fire boxes.
Fig. 4 is a side elevation of the boiler only Figs. 5 and 6 are cross sections
thereof on lines oo and z respectively.
Fig. 7 is a horizontal section on line Fig. 6.
It may be here briefly mentioned that the boiler to which the improved firing is
shown as applied is constructed upon the principle that the lower set or sets of fire
tubes running rearward from the fire box are encircled cach by a boiler plating
distinct from that surrounding the return tubes; the water spaces of these several
parts of the boiler communicate by passages at yg as shown in Fig. 3 and also by
the space within the double walls ii of a flue B which carries the gases from the
outward tubes a' or to the return tubes c', the flue B being peculiarly connected
to the boiler parts a b and c the back tube plates of these parts being discontinued
at a and c for free communication with the spaces ff between the walls of the
flue. The duplication of the outward going tubes a' gives to the boiler a very
stable form while the division of the boiler into three parts a band c results in a
great saving of space as compared with the usual form of cylindrical boiler shown
by the dotted line in Fig. 5 without diminishing the heating surface, and gives a
boiler of greater strength capable of being worked at a higher pressure. As the
increase of heating surface obtainable by having a multitude of outward going
tubes a b' in place of one tube for internal firing, can be had only by outside firing with

page_text: the loss of space entailed thereby, it is of importance to minimise this loss of space
and this is effected in a very great measure by the present invention by arranging
for each set of outward going or lower flame tubes a¹ or a double or twin grate
consisting of two grates one above the other, each having its separate stoking
opening with door, its separate fuel chamber and ash chamber. These are contained
within a casing which is double to receive water so that each furnace is water
jacketted, a circulation of cold water being kept up therein.
3 3 3 3
Such a system of firing is illustrated, H being the double casing forming two
chambers one above the other. and are the fire grates in these chambers.
and being the respective ash spaces; c c¹ the respective fuel spaces, and the
respective stoking doors, d and d' the respective orifices from which the flames issue
to pass into the flame tubes a¹ or 6 to whichever the twin grate is applied.
are short lengths of tube passing through the water jacketted wall and admitting
fresh air to the combustion chambers. There are as many of these twin grates as
there are flame tubes or systems to be fired and each of the casings H is made
separate and preferably mounted on wheels as shown so that when disconnected it
can be run back for repairs to itself or to the boiler. For this purpose the water
supply to the jackets H should be made so that it may be easily disconnected. Fig. 1
shows such a water supply derived from the sea through a system of main and branch
pipes n the waste water passing off by a similar system of pipes n¹ above the water
level. If necessary a pump or other circulating device is employed to cause a flow of
water through the jackets H-or advantage may be taken of the flow of water when
heated, as in hot water heating systems.
The improved firing may be applied to other forms of boiler.
Having now particularly described and ascertained the nature of this said
invention and in what manner the same is to be performed I declare that I make
no claim to anything described or claimed in the Specification of the Patent No. 7703
A.D). 1892 hereinbefore referred to but what I claim is :-
1. A device for the outside firing of steam boilers consisting of a double casing H
forming a water jacket through which a stream of water is adapted to flow, grates
one above the other within said casing each grate having its separate stoking
door, air feeds, ash space and flame outlet substantially as and for the purpose
described.
2. The combination of a double or twin grate as described in Claim 1 with a
boiler in which the lower outward going systems or system of flame tubes and the
upper return system of flame tubes are contained within separate boiler plates or
parts the water spaces of these parts being connected by means of a water space
within a double wall of a flue connecting the outward and return systems of flame
tubes, the whole substantially as and for the purposes described.
Dated this 25th day of August 1892.
HERBERT & Co.,
18, Buckingham Street, Strand, W.C., Agents to Applicant.