Improvements in Steam Boilers, and in Vessels for Heating and Cooling Fluids.
Year: 1896

page_text: Date of Application, 16th July, 1806
Complete Specification Left, 17th Apr., 1897-Accepted, 19th June, 1897
Complete Specification Left, 17th Apr., 1897-Accepted, 19th June, 1897
PROVISIONAL SPECIFICATION.
Improvements in Steam Boilers, and in Vessels for Heating
and Cooling Fluids.
I WILLIAM HENRY WATKINSON of 29 Kerrsland Terrace, Hillhead, Glasgow,
Professor of Engineering in the Glasgow and West of Scotland Technical College,
Glasgow, do hereby declare the nature of this invention to be as follows:-
The objects of my invention are to reduce the amount of tube surface in steam
boilers, superheaters, air heaters and in other vessels for heating or cooling fluids,
and at the same time to increase their efficency.
1 effect these objects by placing the tubes much closer together than has hitherto
been the practice, so that the furnace or other gases to be heated or cooled shall be
subdivided into very thin sheets, and I obtain sufficient flue area by suitably
proportioning the number and diameter of the tubes and by arranging them so that
they all contribute to the flue area. In the case of steam boilers of the water-tube
type I arrange the tubes so as to form, together with the steam and water drums,
when steam and water drums are used, the four sides and top of the fire-box, and
I cause the products of combustion to flow out of this fire-box through the more or
less capillary spaces between the tubes on all the sides and the top of the fire-box.
By this arrangement the heating surface is reduced to a minimum because it is
unnecessary to use more tubes than are required for the walls of the fire-box,
although in some cases it may be desirable to do so. When steam and water
drums are used I use suitable downcomers which may be arranged either within or
without the fire-box. In some cases I use "Field "tubes as the construction may
in this way be simplified and provision for a fire door more easily made by merely
using shorter tubes over the fire door. The boiler may be surrounded by a fire-
brick or other suitable casing at a sufficient distance from the boiler to form
a flue all, round it for the products of combustion on their way to the chimney.
This outside flue may, however, in some cases have its outer walls built up of
tubes fixed quite close together. When two or more boilers are used together the
space between them will form part of the flue.
The tubes are expanded into the drums in the ordinary way and in order to
enable this to be done without unduly weakening the drums the ends of the tubes
may be of smaller diameter, or each alternate tube may have its ends sufficiently
bent to allow the holes in the drums being zig-zagged.
In some cases I arrange to use water-tube fire-bars and in these cases I have the
tubes drawn down to a smaller diameter for this portion of their length. When
the boiler is arranged for forced circulation as in the "Serpollet" type, for example
the steam and water drums may be dispensed with and the construction of the
boiler simplified.
In order to facilitate combustion I in some cases build inside the fire-box
a combustion chamber of fire-brick, or other suitable bad conductor of heat, the
walls of this combustion chamber being at a sufficient distance from the tubes
forming the fire-box to allow the products of combustion to flow freely to the tubes.
The downcomers connecting the upper and lower drums may be shielded by the
walls of this combustion chamber.
The above described arrangement may be used as an independent superheater or

page_text: for heating air, water or other fluids but when the products of combustion from
another furnace are to be used for these purposes the tubes may be arranged in a
sinuous form in order to reduce the amount of space occupied. This latter
arrangement will also in most cases be the most convenient for cooling purposes, as
for example, where it is desired to cool a current of air by means of cold brine
flowing through the tubes, also for the condensation of vapour either by means of a
current of cool water flowing through the tubes or a current of air acting on the
outside while the vapour is condensed within the tubes in this last case.
Improvements in Steam Boilers, and in Vessels for Heating
and Cooling Fluids.
I, WILLIAM HENRY WATKINSON of 29 Kerrsland Terrace, Hillhead, Glasgow,
Professor of Engineering in the Glasgow and West of Scotland Technical College,
Glasgow do hereby declare the nature of this invention and in what mauner the
same is to be performed, to be particularly described and ascertained in and by the
following statement:-
The objects of my invention are to reduce the amount of tube surface in steam
boilers, superheaters, air-heaters and in other vessels for heating or cooling fluids,
and at the same time to increase their efficiency.
I effect these objects by placing the tubes much closer together than has hitherto
been the practice, so that the furnace or other gases to be heated or cooled shall be
subdivided into very thin sheets, and I obtain sufficient flue area by suitably
proportioning the number and diameter of the tubes and by arranging them so that
they all contribute to the flue area.
In the case of steam boilers of the water-tube type I arrange the tubes so as to
form, together with the steam and water drums, when steam and water drums are
used, the four sides and top of the fire-box and I cause the products of combustion
to flow out of this fire-box through the more or less capillary spaces between the
tubes on all sides and the top of the fire-box. By this arrangement the heating
surface is reduced to a minimum because it is unnecessary to use more tubes than
are required for the walls of the fire-box, although in some cases it may be
desirable to do so. When steam and water drums are used I use suitable down-
comers which may be arranged either within or without the fire-box. In some
cases I use "Field " tubes as the construction may in this way be simplified and
provision for a fire-door more easily made by merely using shorter tubes over the
fire-door. The boiler may be surrounded by a fire-brick or other suitable casing at
a sufficient distance from the boiler to form a flue all round it for the products of
combustion on their way to the chimney. This outside flue may, however, in some
cases have its outer walls built up of tubes fixed quite close together. When two
or more boilers are used together the space between them will form part of
the flue.
The tubes are expanded into the drums in the ordinary way and in order to
enable this to be done without unduly weakening the drums the ends of the tubes
may be of smaller diameter, or each alternate tube may have its ends sufficiently
bent to allow the holes in the drums being zig-zagged.
In some cases I arrange to use water-tube fire-bars and in these cases I have the
tubes drawn down to a smaller diameter for this portion of their length. When
the boiler is arranged for forced circulation as in the "Serpollet" type, for example

page_text: the steam and water drums may be dispensed with and the construction of the
boiler simplified.
In order to facilitate combustion I, in some cases, build inside the fire-box
combustion chamber of fire-brick, or other suitable bad conductor of heat, the
walls of this combustion chamber being at a sufficient distance from the tubes
forming the fire-box to allow the products of combustion to flow freely to the tubes.
The downcomers connecting the upper and lower drums may be shielded by the
walls of this combustion chamber.
The above described arrangement may be used as an independent superheater, or
for. heating air, water or other fluids, but when the products of combustion from
another furnace are to be used for these purposes the tubes may be arranged in
a sinuous form in order to reduce the amount of space occupied.
This latter arrangement will also, in most cases, be the most convenient for
cooling purposes, as for example, where it is desired to cool a current of air by
means of cold brine flowing through the tubes, also for the condensation of vapour,
either by means of a current of cool water flowing through the tubes, or a current
of air acting on the outside while the vapour is condensed within the tubes in this
last case.
The nature of my invention will be better understood by reference to the
accompanying four sheets of drawings, in which the same letters refer to similar
parts throughout the several views.
On Sheet 1. Figures 1, 2, and 3 illustrate one form of my improved steam
boiler.
Fig. 1 is a half end elevation and a half transverse section.
Fig. 2 is a half longitudinal section and a half side elevation, with part of the
casing cut away.
Fig. 3 is a plan, partly in section.
a, is the steam and water drum into which the discharge from the tubes takes
place at about the water level; b, is the lower water drum; c, is the "downcomer,"
or pipe by which the water flows from the upper drum, a, to the lower drum, b;
d, d, d.......d are the tubes constituting the principal heating surface of the
boiler.
In Figs. 1, 2, and 3, Sheet I, the tubes are elliptical in section, excepting at
their ends, which are left round for expanding into the drums, as illustrated in
detail in Fig. 4.
In Fig. 5, which shows a portion of a boiler, the tubes are round throughout
the whole of their length, and each alternate tube has its ends sufficiently bent to
allow the holes in the drums being zig-zagged.
Figs. 1, and 2, Sheet 2 show another modification of my improved boiler.
f, is the mouth of the furnace, and above this the tubes are expanded into
the bent header, g, this header being connected to the water drum, b, by the
nipples, h.
A suitable door or doors are provided in the header, g, to enable the tubes to be
expanded into it.
Figs. 1, 2, and 3, Sheet 3, illustrate one form of the application of my invention
to a steam superheater.
The tubes, d, are so close together that in the figures they appear to be touching
each other. The tubes, d, are expanded or otherwise fixed into the pipes, a,
and these pipes are connected, as shown, by the bent pipes c, and c. The
arrows indicate the direction of flow of the steam and of the furnace gases.
The baffles, k, k,..... k, Fig. 3, Sheet 3, cause the gases to flow through the
thin spaces between the tubes, and thus they give up their heat more efficiently to
the tubes through which the steam flows.
Instead of the two elements of the superheater being connected in parallel as
shown in Fig. 3, Sheet 3, they may be connected in series both as regards the flow
of the steam and the flow of the furnace gases.
Another modification of my improved superheater is shown on Sheet IV.

page_text: Fig. 2. is an elevation.
Fig. 3 is part sectional plan showing the steam pipe divided into two parts by
a. longl. diaphram.
In this modification the tubes, d, are coiled and any suitable number of coils may
be connected either side by side or end to end to the divided steam pipe, a.
In Fig. 1, two coils are shown side by side, and Figs. 2 and 3 show four coils end
to end, all these coils being connected to the pipe either by expanding the tubes in
the usual way or by contracting the pipe on to the tubes.
Suitable baffles are provided in the flues as well as transversely within the coils,
so that the furnace gases are compelled to pass in thin sheets through the narrow
spaces between the various convolutions of the tubes.
From the above descriptions the application of my invention to air-heaters,
condensers and, in general, to vessels for the heating and cooling of fluids, is
obvious.
.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what I
claim is.-
I. In a steam boiler the arrangement and combination of a series of tubes
forming the sides of a fire-box and fixed at such small distances apart that the
products of combustion are divided into thin sheets in passing between the tubes on
their way to the chimney, together with the steam and water-drums and down-
comers, in the manner and for the purposes substantially as herein described
and illustrated by the figures in the accompanying first and second sheets of
drawings.
II. In a steam boiler the arrangement and combination consisting of a number of
tubes or of coils of tubing fixed at very small distances apart and of an inner
combustion chamber of firebrick or of other suitable refractory material, in the
manner and for the purposes substantially as herein described.
III. In a steam boiler, or adjunct to a steam boiler, the arrangement and
combination of a number of tubes or coils of tubing together with the necessary
headers into which the tubes or coils of tubing are fixed at such small distances
apart that the products of combustion are divided into thin sheets in passing
between the tubes or coils of tubing on their way to the chimney, such combination
and arrangement being used either for generating steam or for heating the feed
water (the furnace being either internal or external) in the manner and for the
purposes substantially as herein described.
IV. In a steam boiler of the Serpollet or coil types the arrangement and
combination of tubes or coils of tubing fixed at such small distances apart that the
products of combustion are divided into thin sheets in passing between the tubes or
between the successive convolutions of coils of tubing on their way to the chimney
in the manner and for the purposes substantially as herein described.
V. In a steam super heater the arrangement and combination of a number of
tubes or a number of coils of tubes, together with the necessary headers into which
the tubes, or coils of tubes are fixed at such small distances apart that the products
of combustion are divided into thin sheets in passing between the tubes on their
way to the chimney, in the manner and for the purposes substantially as herein
described and illustrated by the figures in the accompanying third and fourth sheets
of drawings.
VI. In a condenser the arrangement and combination of tubes, fixed at such
small distances apart that the steam is divided into thin sheets in passing between
the tubes, the cooling water in this case being passed through the tubes, in the
manner and for the purposes substantially as herein described.
VII. In a condenser the arrangement and combination of tubes fixed at such
small distances apart that the cooling water is divided into thin sheets in passing

page_text: between the tubes, the steam in this case being condensed within the tubes, in the.
manner and for the purposes substantially as herein described.
VIII. In vessels for the heating and cooling of fluids in general the arrangement
and combination of tubes fixed at such small distances apart that the fluid passing
between them is divided into thin sheets, in the manner and for the purposes
substantially as herein described.
W. H. WATKINSON.