Year: 1897

page_text: I, CHARLES DOWSEN, of 21, Croft Terrace, Jarrow-on-Tyne, Mechanical Engineer,
do hereby declare the nature of this invention to be as follows:--
The object of this invention is to produce a compact and efficient steam generator
of the tubulous type, composed of parts of simple construction, readily accessible for
examination and repair.
For this purpose, my improved steam generator is constructed as, or substantially
as, I will now proceed to explain, with reference to the accompanying illustrative draw-
ings, whereof
Fig. 1 shows, partly in end elevation, and partly in transverse vertical section, a
steam generator in accordance with my invention, Fig. 2 is a central longitudinal
vertical section Figs. 3, 4 and 5 illustrate to a larger scale the method of securing the
tubes, and Fig. 6 is a view, partly in end elevation and partly in transverse vertical
section, showing a modified construction.
As will be seen, my improved steam generator is of the kind wherein an upper
water and steam chamber a and lower water chambers 6 are connected by water tubes,
some of which form furnace and flue walls.
The connecting tubes c are connected at their lower ends by joints of the kind
represented in Figs. 3 to 5 inclusive, to the water chambers b and at their upper ends
by similar joints to the water and steam chamber a and are so formed that for a part
of their length, commencing from near their lower ends, they are vertical or nearly
vertical, then for a part of their length are bent to a suitable curve in an inward
direction, the curve being succeeded by a straight, or practically straight, portion in
an inclined direction, which may be nearly horizontal, and which, in the case of some
of the tubes, extends to the upper water and steam chamber a, whilst in the case of
others, this straight, or approximately straight, portion is connected to the said
chamber by a bend.
The form of joint whereby the connecting tubes are secured to the upper and
lower chambers a and b will be readily understood on reference to Figs. 3 to 5
inclusive.
Referring to Fig. 4, a' is a portion of the tube plate through which a hole is bored,
which hole, for the greater portion of its length, is, in the first instance, made
cylindrical, but terminates in a portion of gradually-decreasing diameter.
The cylindrical part of the hole is formed with a screw thread, as is also the
exterior of the end of the tube c to be fixed, which tube is of appreciably smaller
external diameter than the hole.
e is a ferrule or annular plug, formed externally with a screw thread adapted to
engage with that of the hole in the plate, and internally with a screw thread corre-
sponding to that on the exterior of the tuhe end c. That end of the ferrule or annular
plug which enters the hole in the plate, is made of a tapering form and is formed
externally as a frustum of a cone, the arrangement being such that when, through

page_text: the medium of a suitable tool applied to the polygonal head e¹ of the ferrule or
annular plug, it is screwed home, its smaller end will, by the inclined formation of
the corresponding part of the hole in the plate, be pressed tightly around the tube c,
in such wise as to inake a tight joint between it and the plate, to which end, in some
cases, radial slits are formed in the end of the ferrule or annular plug, as at e². The
inclined portion of the hole might be so formed that its surface will be curved either
inwardly or outwardly as seen in vertical section.
The two rows of tubes farthest from the fire have their vertical or nearly vertical
portions c¹ so disposed that they form a closed wall for the purpose of confining the
hot products of combustion, thus tending to keep the casing f cool. A similar
arrangement is adopted with the horizontal or nearly horizontal portions of two rows
at about the middle of the assemblage of tubes, as for example, at c², the object being
to so divert or baffle the hot gases as to more effectually impart their heat to the
tubes. The lower ends of the tubes c are shown made of reduced diameter in order
to leave sufficient metal between the holes in the lower water chamber b.
The course of the hot gases is indicated approximately by arrows.
g is a pipe (or there may be more than one) of larger diameter than the pipes c;
this pipe g is jointed to the lower part of the top chamber a and is connected by other
pipes g (see Fig. 1) to the lower water chambers b; the lower end 92 of the pipe g
forms a pocket or mud collector, and is fitted with a door as indicated.
The object of the pipes g, gl is to provide for downward circulation of water to
supply the two lower chambers and the connecting tubes c with the necessary water
for evaporation and circulation. It is to be noted that suitable openings with doors
or covers are to be provided, as well understood in steam generators of this class, to
afford access to the interior of the upper and lower chambers and to enable tubes to
be fixed and withdrawn, and so on.
Other details of construction will be readily understood from the drawings. Such
a steam generator is, of course, to be provided with the usual blow-off cocks and other
fittings.
Referring now to the modification shown in Fig. 6, instead of bending the
connecting water tubes as in the previous example, there are employed in this case
two distinct sets of vertical or nearly vertical tubes c (one set at each side of the
furnace) and two sets of horizontal or nearly horizontal tubes c³.
The vertical or nearly vertical tubes c of each set are connected at their upper ends
by joints such as described with reference to Figs. 3 to 5 inclusive to a longitudinal
chamber h, and at their lower ends by similar joints to the corresponding lower water
chamber b. The chambers b in the example are represented as being made with flat
tops and with moveable bottoms b¹.
The horizontal or approximately horizontal tubes c³ are connected at one end by
joints such as already referred to, to the side (shown flat) of the chamber h and at
the other end to the side (portion of which is shown flat) of the top chamber a.
Sometimes I provide at each side of the furnace one or more rows of tubes c*,
arranged to directly connect the lower water chambers b with the corresponding sides
of the top chamber a and to baffle the hot gases in a similar manner to the wall of
tubes c² in Fig. 1.

page_text: Improvements in water Tube Steam Gelerators.
I, CHARLES DOWSEN, of 21, Croft Terrace, Jarrow-on-Tyne, Mechanical 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 :-
The object of this invention is to produce a compact and efficient steam generator
of the tubulous type, composed of parts of simple construction, readily accessible for
examination and repair.
.
For this purpose, my improved steam generator is constructed as, or substantially
as, I will now proceed to explain, with reference to the illustrative drawings, filed
with my Provisional Specification, whereof
Fig. 1 shows, partly in end elevation, and partly in transverse vertical section, a
steam generator in accordance with my invention;
Fig. 2 is a central longitudinal vertical section.
Figs. 3, 4, and 5 illustrate, to a larger scale, the method of securing the
tubes, and
Fig. 6 is a view, partly in end elevation and partly in transverse vertical section,
showing a modified construction.
As will be seen, my improved steam generator is of the kind wherein an upper
water and steam chamber a and lower water chambers 6 are connected by water tubes,
some of which form furnace and flue walls.
The connecting tubes c are connected at their lower ends by joints of the kind
represented in Figs. 3 to 5 inclusive, to the water chambers b, and at their upper
ends by similar joints to the water and steam chamber a, and are so formed that for
a part of their length, commencing from near their lower ends, they are vertical or
nearly vertical, then for a part of their length are bent to a suitable curve in an
inward direction, the curve being succeeded by a straight, or practically straight,
portion in an inclined direction, which may be nearly horizontal, and which, in the
case of some of the tubes, extends to the upper water and steam chamber a, whilst in
the case of others, this straight, or approximately straight, portion is connected
to the said chamber by a bend.
The form of joint whereby the connecting tubes are secured to the upper and
lower chambers a and b will be readily understood on reference to Figs. 3 to 5
inclusive.
Referring to Fig. 4, a¹ is a portion of the tube plate through which a hole is bored,
which hole, for the greater portion of its length, is, in the first instance, made
cylindrical, but terminates in a portion of gradually-decreasing diameter.
The cylindrical part of the hole is formed with a screw thread, as is also the
exterior of the end of the tube c to be fixed, which tube is of appreciably smaller
external diameter than the hole.
e is a ferrule or annular plug, formed externally with a screw thread adapted to
engage with that of the hole in the plate, and internally with a screw thread
corresponding to that on the exterior of the tube end c. That end of the ferrule or
annular plug which enters the hole in the plate, is made of a tapering form and is
formed externally as a frustum of a cone, the arrangement being such that when,
through the medium of a suitable tool applied to the polygonal head el of the
ferrule or annular plug, it is screwed home, its sinaller end will, by the inclined
formation of the corresponding part of the hole in the plate, be pressed tightly around
the tube c, in such wise as to make a tight joint between it and the plate, to which
end, in soine cases, radial slits are formed in the end of the ferrule or annular plug,

page_text: as at e². The inclined portion of the hole might be so formed that its surface would
be curved either inwardly or outwardly as seen in vertical section. The annular plug
may be advantageously made of yellow brass or white metal.
The two rows of tubes farthest from the fire have their vertical or nearly vertical
portions c¹ so disposed that they form a closed wall for the purpose of confining the
hot products of combustion, thus tending to keep the casing f cool. A similar
arrangement is adopted with the horizontal or nearly horizontal portions of two rows
at about the middle of the assemblage of tubes, as for example, at c2, the object being
to so divert or baffle the hot gases as to more effectually impart their heat to the
tubes. The lower ends of the tubes c are shown made of reduced diameter in order
to leave sufficient metal between the holes in the lower water chamber. b.
The course of the hot gases is indicated approximately by arrows.
g is a pipe (or there may be more than one) of larger diameter than the pipes c;
this pipe g is jointed to the lower part of the top chamber a and is connected by
other pipes g¹ (see Fig. 1) to the lower water chambers b; the lower end g² of the
pipe g forms a pocket or mud collector, and is fitted with a door as indicated.
The object of the pipes g, g¹ is to provide for downward circulation of water to
supply the two lower chambers and the connecting tubes c with the necessary water
for evaporation and circulation. It is to be noted that suitable openings with doors
or covers are to be provided, as well understood in steam generators of this class, to
afford access to the interiors of the upper and lower chambers and to enable tubes to
be fixed and withdrawn, and so on.
Other details of construction will be readily understood from the drawings.
Such a steam generator is, of course, to be provided with the usual blow-off cocks
and other fittings.
Referring now to the modification shown in Fig. 6, instead of bending the connecting
water tubes as in the previous example, there are employed in this case two distinct
sets of vertical or nearly vertical tubes c (one set at each side of the furnace) and two
sets of horizontal or nearly horizontal tubes c³.
The vertical or nearly vertical tubes c of each set are connected at their upper ends
by joints such as described with reference to Figs. 3 to 5 inclusive to a longitudinal
chamber h, and at their lower ends by similar joints to the corresponding lower water
chamber b. The chambers b in the example are represented as being made with flat
tops and with moveable bottoms b¹.
The horizontal or approximately horizontal tubes 3 are connected at one end by
joints such as already referred to, to the side (shown flat) of the chamber h and at
the other end to the side (a portion of which is shown flat) of the top chamber a.
Sometimes I provide at each side of the furnace one or more rows of tubes c',
arranged to directly connect the lower water chambers 6 with the corresponding sides
of the top chamber a, and to baffle the hot gases in a similar manner to the wall of
tubes c2 in Fig. 1.
Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed I declare that what I
claim is :-
1. My improved water tube steam generator as herein before described with reference
to and illustrated by Figs. 1 to 5 inclusive of the drawings left with my Provisional
Specification.
2. The modified construction herein before described with reference to and illustrated
by Fig. 6 of the said drawings.
3. In a water-tube steam generator making the joints between the water tubes and
the chambers with which they are directly connected in the manner illustrated by
Figs. 3 to 5 inclusive of the drawings left with my Provisional Specification, the
ferrules or annular plugs being formed with both internal and external screw threads
fitting respectively externally threaded portions of the tubes and internally threaded
portions of holes formed in the said chambers, which holes are made with portions of
gradually decreasing diameter that are not screw-threaded and into which the ends

page_text: of the ferrules or annular plugs are forced by screwing the plugs home so that they
press tightly against the tubes and make tight joints, all as herein before
described.
Dated this 17th day of February 1808
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C., Chartered Patent Agent.