Improvements in and relating to Steam Boilers.
Year: 1890

page_text: Date of Application, 13th Sept., 1890
Complete: Specification Left, 15th June, 1891-Accepted, 18th July, 1891
PROVISIONAL SPECIFICATION.
Improvements in and relating to Steam Boilers.
I, JOHN WATT, of 174 Cleveland Street, Birkenhead, in the County of Chester,
Engineer, do hereby declare the nature of this invention to be as follows:-
My present invention has reference especially to water tube or tubulous boilers,
although it is in part applicable to externally fired boilers generally.
In the Complete Specification of a Patent granted to me, No. 3011 and dated
8th November 1871, I have described and illustrated various forms and details of
water tube boilers; my present invention consists in part of improvements specially
applicable to the details there shown.
I find it desirable, especially where the boilers are to be worked under forced
draught, to make the tubes near the furnace of greater diameter than those more
remote.
I fix the tubes into the tube plates as follows; the tubes are long enough to pro-
ject some little distance through the front and back tube plates and the projecting
ends are threaded; the tubes are expanded in the ordinary way where they fit in
the tube plates, which I find makes a staunch and reliable joint. It is desirable,
however; to tie the back and front tube plates together by means of light nuts
screwed on each end of some or all of the tubes; the threads are removed from the
nuts for a small distance on that side which abuts against the tube plates, in order
to clear the expanded parts of the tubes..
For the purpose of admitting air above the fuel, to facilitate complete combustion,
I fit.tubes, protected. by a refractory covering, in the furnace, sufficiently high to
clear the stoking appliances. These tubes have openings or nozzles directed pre-
ferably downwards into the furnace, and are adapted to admit air or a mixture of air
and steam under pressure thereto.
In the case of tubulous, and of externally fired boilers generally, the furnaces,
flues, and uptakes are enclosed by walls of some refractory and nonconducting
material; one of the objects of my invention is to construct part of these walls so
that they shall form a feed heating apparatus. With this object, I form part of
the said walls of rows of parallel tubes, preferably vertical and close together side
by side.. These tubes lead from one or more trunk feed pipes at the bottom of the
boiler to one or more similar trunk pipes at the top of the boiler. The feed water
enters the lower trunk pipe or pipes, rises through the tubulous wall or water casing
to the upper trunk pipe or pipes, and is delivered to any desired part of the boiler,
being heated by the furnace gases in its passage through the water casing. I
generally prefer to deliver the heated feed water to the boiler as far as possible
from the furnaces thereof, and to direct its flow within the boiler by suitable
diaphragms or the like, whereby it is caused to traverse an assigned path before
reaching the hottest part of the boiler.
1
The tubes of the water casing are fixed into the trunk pipes in any convenient
way; I prefer to make the said trunk pipes in halves united by longitudinal flanges
and: to fix the tubes: therein by expanding; in order to leave sufficient metal between
thet tubes, I either contract their ends or crank them alternately in opposite direc-
tions. The water casing is covered externally to any desired thickness with
suitable nonconducting material, intervals being left where necessary between the
tubes and closed by doors in order to afford access to the flues and uptake; it is
also desirable in some cases to protect the water casing from the intense heat of the
furnace by an internal covering of some refractory material extending to a sufficient
height.

page_text: In some cases, instead of delivering the heated feed water direct to the boiler, I
pass it through a feed heater placed in the uptake and preferably above the boiler.
This feed heater closely resembles the tubulous boilers set forth in my prior
Patent aforesaid, that is to say, it consists essentially of two opposite water chambers
connected by water tubes. The feed water is delivered to the feed heater from the
upper trunk pipe of the water casing, if the latter is fitted, or otherwise direct
from the feed pump, and is then led from the top of the feed heater to the
boiler.
Instead of making the feed heater distinct from the boiler and connecting it
thereto by a pipe or pipes as described, the feed heater may be incorporated with
the boiler by extending the water chambers of the latter sufficiently to form the
water chambers of the feed heater. In either case, diaphragms or the like are
fitted to cause the feed water to traverse an assigned path through the feed heater,
towards the more heated part of the boiler.
Dated this 12th day of September 1890.
SLOAN & LLOYD BARNES,
Castle Chambers, 26, Castle Street, Liverpool, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in and relating to Steam Boilers.
I, JOHN WATT, of 174 Cleveland Street, Birkenhead, in the County of Chester,
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 :-
My present invention has reference especially to water tube or tubulous boilers,
although it is in part applicable to externally fired boilers generally.
In the Complete Specification of a Patent granted to me, No. 3011 and dated
8th November 1871, I have described and illustrated various forms and details of
water tube boilers; my present invention consists in part of improvements specially
applicable to the details there shown.
I find it desirable, especially where the boilers are to be worked under forced
draught, to make the tubes near the furnace of greater diameter than those more
remote.
I fix the tubes into the tube plates as follows; the tubes are long enough to pro-
ject some little distance through the front and back tube plates and the projecting
ends are threaded; the tubes are expanded in the ordinary way where they fit in
the tube plates, which I find makes a staunch and reliable joint. It is desirable,
however, to tie the back and front tube plates together by means of light nuts
screwed on each end of some or all of the tubes; the threads are removed from the
nuts for a small distance on that side which abuts against the tube plates, in order
to clear the expanded parts of the tubes.
For the purpose of admitting air above the fuel, to facilitate complete combustion,
I fit tubes, protected by a refractory covering, in the furnace, sufficiently high to
clear the stoking appliances. These tubes have openings or nozzles directed prefer-
ably downwards into the furnace, and are adapted to admit air or a mixture of air
and steam under pressure thereto.
In the case of tubulous, and of externally fired boilers generally, the furnaces,
flues, and uptakes are enclosed by walls of some refractory and nonconducting
material; one of the objects of my invention is to construct part of these walls so
that they shall form a feed heating apparatus. With this object, I form part of the
said walls of rows of parallel tubes, preferably vertical and close. together side by
side. These tubes lead from one or more trunk feed pipes at the bottom of the
boiler to one or more similar trunk pipes at the top of the boiler. The feed water
enters the lower trunk pipe or pipes, rises through the tubulous wall or water. casing

page_text: to the upper trunk pipe or pipes, and is delivered to any desired part of the boiler,
being heated by the furnace gases in its passage through the water casing. I
generally prefer to deliver the heated feed water to the boiler as far as possible
from the furnaces thereof, and to direct its flow within the boiler by suitable
diaphragms or the like, whereby it is caused to traverse an assigned path before
reaching the hottest part of the boiler.
The tubes of the water casing are fixed into the trunk pipes in any convenient
way; I prefer to make the said trunk pipes in two portions united by longitudinal
flanges and to fix the tubes therein by expanding; in order to leave sufficient metal
between the tubes, I either contract their ends or crank them alternately in opposite
directions. The water casing is covered externally to any desired thickness with
suitable nonconducting material, intervals being left where necessary between the
tubes and closed by doors in order to afford access to the flues and uptake; it is
also desirable in some cases to protect the water casing from the intense heat of
the furnace by an internal covering of some refractory material extending to a
sufficient height.
In some cases, instead of delivering the heated feed water direct to the boiler,
I pass it through a feed heater placed in the uptake and preferably above the
boiler.
This feed heater closely resembles the tubulous boilers set forth in my prior
Patent aforesaid, that is to say, it consists essentially of two opposite water chambers
connected by water tubes. The feed water is delivered to the feed heater from the
upper trunk pipe of the water casing, if the latter is fitted, or otherwise direct from
the feed pump, and is then led from the top of the feed heater to the boiler.
Instead of making the feed heater distinct from the boiler and connecting it
thereto by a pipe or pipes as described, the feed heater may be incorporated with
the boiler by extending the water chambers of the latter sufficiently to form the
water chambers of the feed heater. In either case, diaphragms or the like are
fitted to cause the feed water to traverse an assigned path through the feed heater,
towards the more heated part of the boiler.
In the accompanying drawings which illustrate my invention,
Figs. I and II show a tubulous boiler with a feed heater, distinct from the
boiler, placed in the uptake; Fig. I is a sectional side elevation on the line A A. of
Fig. II, with the tubulous wall (partly broken away) shown in front of the plane
of section; Fig. II is a front elevation, partly in section on the line B B of
Fig. I.
Figs. III and IV are views, analogous to Figs. I and II, of a tubulous boiler
with a feed heater incorporated therewith by extending the water chambers of the
boiler, and
Figs. V to VIII show details.
Throughout the drawings similar parts are indicated by the same reference
figures, and in the case of sections, the direction in which they are viewed is
indicated by the small arrows placed adjacent to the letters denoting the plane of
section.
Referring to Figs. I and II, 1 is the front and 2 is the back water chamber, con-
nected by the tubes 3 and 4, the latter being of larger diameter as shown; only one
row of the larger tubes is shown but more may be fitted if preferred; removable
plugs as shown are provided to give access to the tubes, and the water chambers
are strengthened by stays which are not shown in the drawings.
It will be seen that in the case of the larger tubes 4 which are exposed to the
intense heat of the furnace, the volume of water is greater in relation to the
heating surface than in the case of the smaller tubes 3 which are more remote from
the furnace, the object being to prevent overheating of the tubes near the furnace.
The water chambers are surmounted by the steam drums 5 with which they com-
municate through the passages 6.
7,7 are the lower feed trunk pipes, joined by the connecting pipe 8, and com-
municating with the upper feed trunk pipes 71, 71 by the tubulous walls or water

page_text: casings 9; the main feed may conveniently be led into one of the trunk pipes '7'and
the auxiliary feed into the other. 27 are openings in the water casings closed by
doors to give access to the furnace and uptake. The feed water after ascending
the water casings enters the front water chamber 10 of 'the "feed 'heater at 11,
traverses the tubes 12 exposed to the furnace gases, enters the back chamber '13 of
the feed heater and finally enters the boiler by 'the pipe 14; in the arrangement
drawn, the 'feed water only traverses the length of the feed "heater once but the
tubes may be divided into stacks and diaphragms fitted in the water chambers in
the well known manner so as to cause the feed water to traverse the length of the
feed heater more than once.
As the feed water entering the feed trunk pipes is comparatively cool, the water
casings will, in addition to utilising some of the waste heat, serve as a screen to
keep down the temperature of the boiler room; there is also considerable advan-
tage in heating the feed water before it enters the tubes of the feed water heater
which are exposed to a comparatively high temperature.
The tubes 9 are placed as close together as possible, only sufficient clearance
being left to prevent difficulty in entering their ends into the holes in the trunk
pipes. In some cases I carry the water walls partially over the top of the feed
heater so as more fully to enclose the uptake.
15 (see Figs. III and IV) are tubes protected by a refractory covering and 'fitted
with nozzles 16 for the purpose of admitting air, or a mixture of air and steam,
under pressure into the furnace in order to facilitate complete combustion. These
nozzles distribute the air over and direct it downwards onto the surface of the fuel
and the number and position of the tubes 15 and nozzles 16 may be modified to suit
circumstances.
-are
Referring now to Figs. III and IV, the water chambers of the feed heater a
extensions of the water chambers of the boiler; the portion 17 is divided off by the
diaphragm 18 so that the feed water entering at 11 traverses the stack of tubes 19
to the portion 20 which is divided off by the diaphragm 21 so that the feed water
returns through the stack 22 to the front of the boiler and finally flows over 'the
upturned edge 24 of the diaphragm 23 and mingles with the water in the boiler.
In other respects the construction resembles that already described.
Fig. V shows to a larger scale the tube ends and nuts; as already stated, the
tube ends are threaded and the tubes are expanded in the ordinary way where they
fit into the tube plates; the nuts 25 project beyond the tubes and have notches 26
for screwing thein up and the thread is removed for a short distance to clear the
part of the tube which is swelled by the expanding tool. The object of these nuts
being to tie the front and back water chambers together, they are comparatively
light and need only be fitted to some of the tubes 3 and 4.
Fig. VI is a section through the feed trunk pipe to a larger scale; the axis of
the tubes must be so placed that the expanding tool can be operated through the
opening which is closed by the cover 28.
In Figs. VII and VIII an alternative construction is shown whereby the necessity
of contracting the ends of the tubes 9 is obviated, the tube ends being alternately
cranked slightly in opposite directions so as to leave sufficient métal between them
where they fit in the trunk pipes.
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 what I
claim is ;-
(1) A water tube steam boiler, having the tubes near the furnace of greater
diameter than those more remote, substantially as and for the purpose set forth.
(2) The herein described method of fixing the tubes of a water tube steam boiler
into the tube plates thereof, which consists in expanding the tubes where they 'pass
through the said tube plates and screwing nuts, with the thread partially removed,
on the projecting ends of the tubes, substantially as described and illustrated.
(3) The arrangement for supplying air under pressure to the furnace of an

page_text: externally fired boiler, consisting of one or more tubes extending across the furnace
and fitted with downwardly inclined nozzles whereby the said air is distributed over
and directed downwards on the surface of the fuel, substantially as described and
illustrated.
(4) In externally fired boilers, constructing the walls which enclose the furnace
and uptake so as to form a feed water casing consisting of parallel tubes close
together side by side, through which tubes the feed water passes on its way to the
boiler, substantially as set forth.
(5) In externally fired boilers, a feed water casing, enclosing the furnace and
uptake, through which the feed water passes on its way to the boiler, said casing
consisting of parallel tubes close together side by side and leading from one or more
lower trunk feed pipes to one or more upper trunk feed pipes, the ends of the tubes
being contracted or cranked alternately in opposite directions, substantially as
described and illustrated.
(6) A water tube steam boiler having a feed heater formed integral therewith
by dividing off portions of the water chambers of the boiler to form the water
chambers of the feed heater, by means of diaphragms which direct the flow of feed
water, substantially as described.
(7) The combination of a feed heater placed in the uptake of a.water tube steam
boiler and a feed water casing through which the feed water passes on its way to
the said feed heater, substantially as described and illustrated.
(8) The arrangement of boiler, feed water casing and feed heater, substantially
as described and illustrated in Figs. I and II.
(9) The arrangement of boiler, feed water casing and feed heater, substantially
as described and illustrated in Figs. III and IV.
Dated this 12th of June 1891.
SLOAN & LLOYD BARNES,
Castle Chambers, 26, Castle Street, Liverpool, Agents for the Applicant.

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