Improvements in Water Tube Boilers
Year: 1899

page_text: Date of Application, 13th June, 1899 -Accepted, 30th Dec., 1899
COMPLETE SPECIFICATION.
Improvements in Water Tube Boilers,
We, THE PETERSEN WATER TUBE BOILER COMPANY, LIMITED, of 3, Pancras
Lane, Queen Street, in the City of London, and JOIN BROKENSHIRE FURNEAUX,
of Victoria Works, Gateshead-on-Tyne, in the County of Durham, 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 has reference to an improved construction and arrangement of
water tube boiler whereby dry steam can be quickly produced in large quantities
in an economical manner, the construction of the boiler morcover being such
that the various parts can be readily handled and put together by unskilled
persons and form a complete boiler ready for use without its being necessary to
make any special foundation therefor.
For these purposes my improved boiler is constructed as we shall now describe
with reference to the accompanying illustrative drawings wherein Fig. 1 shows
the boiler partly in front elevation and partly in cross section and Fig. 2 in
longitudinal section, Figs. 3 and 4 being detail views at right angles to one
another.
The upper transverse steam and water vessel 1 (hereinafter called the steam
drum) is connected to the lower transverse water vessel 2 by a series of vertically
arranged steam generating elements that are arranged side by side and each of
which is composed of a number of bundles of tubes 3 secured at their ends to
boxes 4 provided with easily removable covers 5 and with tubular unions 6
(Figs. 3 and 4) by which the bundles of tubes and their boxes are connected
together to form an element having front and rear headers, the tubes 3 of each
lower bundle, which is directly over the fire, being made of larger diameter than
the other tubes. The boxes 4 may advantageously be made of such a diameter
as to admit of a large number of water tubes 3, say thirty six tubes each of
14 inches outside diameter, being fixed in each of them except the lowermost
ones which may be provided with eighteen tubes each of 2 inches outside diameter.
By this means a large heating surface can be obtained with great saving in
weight and space as compared with earlier constructions of boilers having similar
bundles of tubes.
Each box 4 is or may advantageously be provided with a centrally arranged
tube 4ª (Figs. 3 and 4) that is fixed in the back or tube plate 4 of the box and
extends through the cover 5. By means of this tube, which may be provided
on its outer end with nuts 4° so as to serve as a stay tube, steam or other fluid
under pressure can be delivered from outside the boiler into the central portion
of the bundle of tubes by suitable means, such as a pipe closed at its inner end
and formed with a number of lateral holes, for the purpose of effecting removal
of soot from the exteriors of the tubes over and amongst which the issuing steam
or other fluid will escape laterally in all directions.
The rear header of each element is connected to the top of the water vessel 2

page_text: by a junction pipe 7, and the front header of the element is connected to the
steam drum 1 above the bottom thereof by a junction pipe 8. Above or opposite
the delivery ends of the several junction pipes 8 is or may be arranged a baffle
plate or device 8" of any suitable construction. The steam drum is supported
above the steam generating elements by a pair of external vee-shaped end supports
one of the legs 9 of each of which supports consists of a pipe that connects the
bottom of the steam drum 1 to the top of the water vessel 2 and acts as a down-
take pipe, the other leg 9" of each support being of angle iron or the like
and resting at its lower end upon the floor or upon a bearing plate 10. By the
construction described it will be seen that an effective circulation of water will
be set up, the water flowing upward through all parts of each steam generating
element and descending the downtake pipes 9.
The front and rear walls 11 and 12 of the casing enclosing the steam generating
elements are carried by angle iron or other metal skeleton frames 13 secured to
a plate metal frame or part box 14 that forms the front, back and bottom of
the fire box 15 and ash pit 17 and constitutes the base or foundation by which
the boiler can be erected upon any suitable level surface without the need of a
special brickwork foundation. The said front and rear walls 11 and 12 are
respectively provided with hinged doors 18 and 19, by opening which and the
covers 5 of the boxes 4. ready access can be had to the tubes 3 for inspecting
cleaning or renewing the same. Each door 18 and 19 preferably comprises, as
shewn, two inner metal plates with interposed layer of asbestos, air or other
bad conductor of heat, and an outer plate with a free or open air space between
it and the inner plates. The front wall of the part frame 14 is formed with
fire door openings 14" normally closed by fire doors 14, and with ash-pit open-
ings 14. Each side wall of the boiler is built up of a number of sections each
comprising a dished or flanged metal plate 20 to the inner side of which is
secured, as by bolts, a number of blocks 22 of refractory material, the several
plates 20 being provided externally with brackets or lugs 23 by which they can
be bolted together to form the complete end wall of the boiler. Metal plates 20°
may be fixed at a short distance from the end plates 20 so as to form therewith
passages through which air will flow and keep the ends of the boiler cool.
To ensure a better distribution of the flame and hot gases amongst the water
tubes 3 than heretofore, the refractory baffle plates 24 placed between the super-
imposed bundles of tubes are arranged to alternate in a transverse direction as
shown in Fig. 1 so that the flame and hot gas escape from each side of the fire
box and move, as indicated by the arrows, alternately in opposite transverse
directions whilst passing to the chimney 25, whereby they are caused to impinge
upon the tubes 3 at right angles thereto, or approximately so, and thus enable
the greatest heating effect to be attained. The front and rear ends of the baffle
plates 24 are provided with upwardly extending flanges 24" to guide the flame
and hot gases across and amongst the tubes 3 and prevent them, as far as
possible, from taking a short path to the chimney.
The fire grate 26 arranged to extend backwardly below practically the whole
length of the water tubes 3 so that the lower groups of such tubes will be heated
throughout their length by the radiant heat of the burning fuel on the fire
grates as well as by the direct heat of the flame and hot gases. The rear end
of the fire box 15 is formed by an inclined block 27 of refractory material
arranged to overhang the lower water vessel 2 and protect the same from the
direct action of the flame and hot gases. The fire grate is divided into two
portions by a longitudinal division 28 of refractory material such as fire brick
or cast iron, so as to form two separate grates and admit of either fire being
cleaned without materially interfering with the generation of steam. The
division 28 may advantageously be made hollow and perforated, as shown, and
be provided at its front end with an air inlet controlled by a sliding damper 29
so as to allow of a regulated quantity of air being admitted to the fire box.
The boiler casing above the groups of tubes 3 and in rear of the steam drum 1,

page_text: is constructed to form a chamber 30 from the top of which the chimney 25
extends. Within the said chamber is arranged a water heater composed of a
number of groups of tubes 31 fixed in end boxes like the tubes 3 and connected
together in series by end pipes 32, the connected series of tubes being provided
at one end with an inlet valve 33 and at the other end with a delivery pipe 34
discharging into the steam drum 1. In order that the feed water shall be
delivered into the steam drum in a highly heated condition, the said water heater
is connected through its inlet valve 33, to an auxiliary feed water heater com-
posed of one or two lengths of piping 35 bent to a zig-zag shape (see Fig. 2) and
arranged at one or at each side of the boiler, as shown in Fig. 1 as regards one
length of such piping, and connected at the lower external end 35 to a feed
pump.
When using feed water that normally contains lime salts in solution, the salts
rendered insoluble by the heating may be separated to a large extent from the
water by discharging the heated water through the pipe 34 into a metal trough 36
supported longitudinally within the steam drum 1 with its edges above the normal
water therein so that the feed water will first enter the trough and then flow over
the edges thereof into the water space in the lower part of the steam drum.
In this way a large proportion of the insoluble matter will be retained in the
trough from which it can be removed from time to time when the boiler is out
of use.
.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed we declare that what
we claim is;-
1. The improved water tube boiler constructed, arranged and operating sub-
stantially as hereinbefore described with reference to and shown in the drawings
annexed.
2. In a boiler of the kind referred to providing substantially in the manner
described and illustrated for the introduction from outside the boiler into the
central portion of a tube bundle of means such as mentioned for effecting removal
of soot from the exteriors of the tubes.
Dated this 18th day of June 1899.
For the Applicants,
W. LLOYD WISE.
46, Lincoln's Inn Fields, London, W.C., Chartered Patent Agent.