AN IMPROVED CONSTRUCTION OF VERTICAL BOILERS AND MEANS OF MAIN- TAINING A Constant Circulation of the WATER THEREIN
Year: 1871

page_text: LETTERS PATENT to Vaughan Pendred, of Crohill House, Milton Road,
Dulwich, in the County of Surrey, Engineer, for the Invention of
"AN IMPROVED CONSTRUCTION OF VERTICAL BOILERS AND MEANS OF MAIN-
TAINING A Constant Circulation of the WATER THEREIN."
PROVISIONAL SPECIFICATION left by the said Vaughan Pendred at the
Office of the Commissioners of Patents, with his Petition, on the
14th March 1871.
I, VAUGHAN PENDRED, of Crohill House, Milton Road, Dulwich, in
the County of Surrey, Engineer, do hereby declare the nature of the said
Invention for "AN IMPROVED CONSTRUCTION OF VERTICAL BOILERS AND MEANS
OF MAINTAINING A CONSTANT CIRCULATION OF THE WATER THEREIN," to be as
follows:-
According to this Invention the fire-box and the outer shell of vertical
boilers are made of circular or elliptical form in the usual manner, but
the inner shell is of square or nearly square shape in cross section and

page_text: has the tubes fitted to it horizontally in any convenient mode, so that
the greatest amount of heat can be taken up by them. The ends of the
tubes have nozzles formed or fitted on them for directing the heated
water from the lower to the upper portion, or in lieu of nozzles curved
plates may be employed, and these may be arranged for one set or one
series of tubes or for the whole number as desired. The tubes will be
preferably laid in layers, cach layer crossing the next; by this means the
products of combustion become broken up before they enter the uptake,
and a quick generation of steam is the result. The nozzles or the plates
on one end of the tubes are curved or bent upwards, while those on the
opposite ends are curved or bent downwards. I propose to fit angle iron
on the lower part of the outer shell and on the fire-box so that the two
can be bolted together; this will facilitate the removal of the outer shell
for cleaning purposes.
The main feature in the Invention is fitting horizontal tubes in a
square casing of vertical boilers and arranging nozzles or curved plates
at the ends to maintain a constant circulation of the heated water.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Vaughan Pendred in the Great Seal Patent Office
on the 14th September 1871.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, VAUGHAN
PENDRED, of Crohill House, Milton Road, Dulwich, in the County of
Surrey, Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fourteenth day of March, in the year
of our Lord One thousand eight hundred and seventy-one, in the thirty-
fourth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Vaughan Pendred Her special licence
that I, the said Vaughan Pendred, my executors, administrators, and
assigns, or such others as I, the said Vaughan Pendred, my executors,
administrators, and assigns, should at any time agree with, and no
others, from time to time and at all times thereafter during the term
therein expressed, should and lawfully might make, use, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "AN IMPROVED

page_text: CONSTRUCTION OF VERTICAL BOILERS AND MEANS OF MAINTAINING A CONSTANT
CIRCULATION OF THE WATER THEREIN," upon, the condition (amongst others)
that I, the said Vaughan Pendred, my executors or administrators, by
an instrument in writing under my, or their, or one of their hands and
seals, should particularly describe and ascertain the nature of the said
Invention, and in what manner the same was to be performed, and cause
the same to be filed in the Great Seal Patent Office within six calendar
months next and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Vaughan Pendred, do hereby declare
the nature of my said Invention, and in what manner the same is to be
performed to be particularly described and ascertained in and by the
following statement thereof, reference being had to the Drawings here-
unto annexed, that is to say :-
According to this Invention the fire-box and the outer shell of vertical
boilers are made of circular or cliptical form in the usual manner, but
the inner shell is of square or nearly square shape in cross section, and
has the tubes fitted to it horizontally in any convenient mode, so that
the greatest amount of heat can be taken up by them.. The ends of the
tubes have nozzles formed or fitted on them for directing the heated
water from the lower to the upper portion; or in lieu of nozzles curved
or shaped plates may be employed, and these may be arranged for one
set or one series of tubes or for the whole number, as desired. The
tubes are preferably laid in layers, each layer crossing the next at right
angles; by this means the products of combustion become broken up
before they enter the uptake, and a quick generation of steam is the
result. The nozzles or the plates on one end of the tubes are curved or
bent upwards, while those on the opposite ends are curved or bent down-
wards. I propose to fit angle iron on or flange the lower part of the
outer shell and the fire-box, so that the two can be bolted together;
this will facilitate the removal of the outer shell for cleaning: purposes..
The main feature in the Invention is fitting horizontal tubes in a
square casing of vertical boilers, and arranging nozzles. or curved plates.
at the ends to maintain a constant circulation of the heated water.
The annexed Sheet of Drawings represents how I propose to carry my
Invention into effect..
Figure 1 is a sectional elevation of a vertical boiler, in which the
outer shell a is of circular shape, as seen in the cross section Figure 2..
The inner shell b. above the fire-box c is of square form with the corners

page_text: rounded for convenience of manufacturing this shell from one sheet of
metal, and thereby employing fewer butt or lap joints than if it were
made of separate plates with corner pieces rivetted on. This inner shell
is secured upon a circular fire-box by a flange e to obtain a large fire
area, but the square form can be carried down to the bottom of the
boiler if found desirable. The square inner shell is provided with
tubes ff, fastened in in any convenient manner, and these have
nozzles g, g¹, driven in at each end, those g in one end being arranged
with their mouths in a downward direction, and those g¹' with their
mouths in an upward direction, to secure the circulation of the water
through the tubes f, f, towards the upper part in a zig-zag manner, and
thereby hasten the generation of steam, the water in the tubes f,f, being
heated to a higher degree by the products of combustion before they
pass away to the uptake or chimney h. In the Drawings I have shown
several layers of tubes ff, in the inner shell, so that all portions of the
water are brought under the action of the heat from the fire; the layers
of tubes cross each other in alternate order, and all the nozzles of each
layer are in the same direction; but I do not in all cases fit them in in
this manner, as they can be fitted alternately in the tubes of each layer,
and the exterior portions of the nozzles may be of such a length as to
come between the nozzles of those above them. The nozzles may be
single or double, or they may be arranged in sets to fit the layers, and
the required number for all the tubes may be formed in a casting or a
framework, if found desirable, with one or more broad or wide outlets.
just below the water line.
As before referred to, the inner shell may have plates fitted to it
covering the entrances and the outlets of the tubes; and these, like the
nozzles, may be single, double, or in sets, and they may be attached to
the inner shell by screw' bolts, rivets, or bands to encircle them and hold
them to the inner shell; or they may be fitted in or to them in any
* convenient manner so long as they are so fitted or arranged for the water
to circulate and the steam to rise to the surface and escape into the
steam space without impediment. Some examples of how I propose to
arrange. the plates on or to the inner shell of a boiler are represented in
the detached views Figs. 3, 4, 5, 6, and 7.
In Fig. 3 all the tubes which are arranged in one direction. have a
kind of box i over their ends, with the opening for the entrance of the
cated body or particles of water to rise into before it or they become,

page_text: as it were, broken up to pass through the tubes, and in which more
heat is taken up before it or they can enter the box j on the opposite
side of the shell, which box is open at the top only, as seen in Figure 5.
Figures 3 and 4 are views of the inner shell, the tubes ff, and the
boxes h, i, thereon.
In Figure 3 I have shown a box in which no ends are arranged to
enter the tubes, but in Figure 4 the boxes have ends. As described
with reference to the nozzles the boxes may be arranged for any
number of tubes; if I use a box for each end, or for two adjoining ends,
I simply bend or otherwise form plates of metal into shape and fasten
them on to the shell or into the tube ends, as shown in Figures 6
and 7, or as deemed advisable. For convenience of fitting in or for
removing the nozzles or the boxes or plates from the inner shell I
attach a ring to a part of the outer shell just above the fire-box, so
that it can be lifted therefrom, the ring being, when in place, attached
to another ring 7 rivetted to the fire-box, as shown in Figure 1. There
is a flanged plate between the uptake and the outer shell a to make
the upper part of the boiler steam-tight, which plate has to be removed
when the rings k and are separated before the outer shell can be
lifted, the aperture in the dome being large enough to clear the curved
top of the chimney if it has one fitted to it.
I have mentioned my nozzles, boxes, or plates as being applicable
to vertical boilers, but by slight modifications they can be arranged to
boilers in which the flame tubes are horizontal, such as in the Cornish
boiler, which flame tubes could be fitted with horizontal transverse
tubes, to which my nozzles, boxes, or plates could be fitted or arranged,
whereby a constant circulation of the water would take place for the
rapid generation of steam, as herein-before described. Nozzles may be
formed at one end of the tubes, and loose ones, fitted on or into the other
ends after the tubes are in place..
And having now described the nature of my said Invention, and in
what manner the same is to be performed, I declare that I claim as my.
Invention,―
Firstly. The employment of nozzles or their equivalents. in, on, or
to the ends of tubes of vertical boilers, when such tubes are fitted
horizontally in the shell, as and for the purposes described.
Secondly. I claim the method of maintaining a constant circulation
of water in vertical boilers, as herein-before described and shown.

page_text: Thirdly. I claim the combination of plates and the inner shells of
boilers, when the two are arranged substantially in the manner and for
the purposes described.
In witness whereof, I, the said Vaughan Pendred, havo hereunto
set my hand and seal, this Fourteenth day of September, in the 5
year of our Lord One thousand eight hundred and seventy-one.
Witness,
H. GARDNER,
166, Fleet Street,
London.
V. PENDRED. (L.S.)