IMPROVEMENTS IN STEAM BOILERS
Year: 1867

page_text: LETTERS PATENT to Isaiah, Kendrick, of Walworth, in the County of
Surrey, Steam Boiler Manufacturer, for the Invention of "IMPROVEMENTS
IN STEAM BOILERS."
Sealed the 24th April 1868, and dated the 81st October 1867.
PROVISIONAL SPECIFICATION left by the said Isaiah Kendrick at
the Office of the Commissioners of Patents, with his Petition, on the
81st October 1867.
I, ISAIAH KENDRICK, of Walworth, in the County of Surrey, Steam Boiler
Manufacturer, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN STEAM BOILERS," to be as follows:-
...My Invention consists in certain improved arrangements of water spaces
in the flues of Cornish and other boilers, whereby the flame and products of
combustion are caused to take a serpentine course. I am aware that boilers
have before been constructed in which the products of combustion travel in a
serpentine manner, but by my arrangements I obtain economy in the con-
struction of the boiler, and at the same time get greater heating power.
I proceed to describe my Invention as applied to Cornish boilers :-I fit at
intervals across the boiler flue (or flues) water spaces of semicircular form

page_text: (or other analogous form) the alternate spaces having the bases of their semi-
circles at or at about right angles to each other, and each base forming an
angle of about 45° with a horizontal line carried across the flue. Each space
fills about one-half the width of the flue, and by the alternating arrangement
before described a serpentine course is left for the products of combustion,
while a clear opening is left along the bottom of the flue to enable a man to
creep through to clean or repair. The curved edge of the semicircular water
spaces may if desired be in contact with the surface of the flue, but I prefer
to leave about 1 or 2 inches between such edge and such surface to allow the
products of combustion to act upon as much surface as possible; thus while
the main portion of the products take the serpentine course, a part passes
between the curved edge of the water spaces and the surface of the flue. The
water spaces are in communication with the main body of water; they may
be secured in place by flanges or otherwise, but I prefer to secure them as
follows: From each corner of the water space I carry a short tube to
connect the space with the main water space; these tubes pass through holes
formed for the purpose in the flue. I secure the lower tube by a double nut,
and then expand the end of the upper tube in the well-known manner; or
if convenient both tubes may be expanded. These tubes act as stays to
the flue, and the angle irons now generally used, or some of them, may be
dispensed with.
Another part of my Invention consists in a mode of combining flat tubes
and round or other analogous form of tubes in steam boilers, such flat tubes
and other tubes forming water spaces communicating with the main body of
water, while the flat tubes both serve as stays to the boiler flues and as a
means of causing the main portion of the products of combustion to take a
serpentine course. I place in the boiler flues vertical flat tubes secured at
top and bottom by flanges and rivets, and placed alternately at opposite sides
of the flue, that is to say, two or other desired number of tubes are placed at
one side extending to about the centre of the flue, and then a like number
are placed at the other side of the flue, and so on alternately at the two sides
so as to form a clear serpentine space for the products of combustion. In
this serpentine space I place a number of vertical or inclined tubes of round
or similar form, which are secured in place by their ends being expanded, or
by flanges and rivets or otherwise. In a long boiler I leave a clear space at
each side of the flue to allow a man to pass along to clean or repair.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Isaiah Kendrick in the Great Seal Patent Office on the
80th April 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ISAIAH
KENDRICK, of Walworth, in the County of Surrey, Steam Boiler Manufacturer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Thirty-first day of October, in the year of our Lord
One thousand eight hundred and sixty-seven, in the thirty-first year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Isaiah Kendrick, Her special licence that I, the said Isaiah Kendrick,
my executors, administrators, and assigns, or such others as I, the said
Isaiah Kendrick, my executors, administrators, and assigns, should at any
time agree with, and no others, from time to time and at all times there-
after 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 "IMPROVE-
MENTS IN STEAM BOILERS," upon the condition (amongst others) that I, the
said Isaiah Kendrick, my executors or administrators, by an instrument in
writing under my, or their, or one of their hands and seals, should par-
ticularly 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 1, the said Isaiah Kendrick, 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 hereunto annexed..
that is to say-
My Invention mainly consists in certain improved arrangements of water
chambers or-spaces-(which I-call-circulating generators) in the flues or tubes.
of Cornish and other boilers, whereby the flame and products of combustion
or some of them are caused to take a serpentine course, or from side to side
and up-and-down manner in their passage from the furnace to the chimney.
I am aware that boilers have before been constructed in which the products
of combustion travel in a serpentine manner, but by my arrangements I
obtain economy in the construction of the boiler, and at the same time get
greater heating power.

page_text: My circulating generators are preferably made flat sided, and with a round
tube top and bottom of suitable size to connect them to the tubes or flues of
the boiler. The top and bottom connecting tubes may be flanged and rivetted
to the tubes or flues, but to facilitate their application or their removal in
čase of repairs being required, I prefer to connect them by the well-known
method of expanding without flanges. These circulating generators when for
the flues or tubes of Cornish boilers I make of a semicircular form and flat
sided, or they may be made of any analogous form and flat sided to suit the
flue or tube in which they are fitted.
I proceed to describe my Invention as applied to Cornish boilers:-I fit at
intervals across the boiler flue (or flues) water chambers or spaces of semi-
circular form (or other analogous form) the alternate chambers having the
bases of their semicircles at or at about right angles to each other, and each
base forming an angle of about 45° with a horizontal line carried across the
flue. Each chamber fills about one-half the diameter of the flue, and by the
alternating arrangement, before described, a serpentine course is left for the
products of combustion, while a clear opening is left along the bottom of
the flue to enable a man to go through to clean or repair. The curved edge
of the semicircular water chambers may, if desired, be in contact with the
surface of the flue, but I prefer to leave about 1 or 2 inches or more between
such edge and such surface to allow the products of combustion to act upon
as much surface as possible; thus while the main portion of the products
takes the serpentine course a part passes between the curved edge of the water
chambers and the surface of the flue, whereby the gases are thoroughly mixed
and the smoke consumed; but in some cases I fill up or partly fill up some
or all of the spaces between the curved edges and the surface of the flue.
The water chambers are in communication with the main body of water and
cause a rapid circulation; they may be secured in place by flanges or othe:-
wise, but I prefer to secure them as follows, and as before referred to:- From
each corner of the water chambers I carry a short tube to connect the
chamber with the main water space; these tubes pass through holes formed
for the pur, ose in the flue. I prefer to secure the upper and lower tube by
expanding the r ends as well known, or they may be secured by flanges or
otherwise if f und desirable. These generators act as strengthening stays to
the flues, and the angle irons now generally used for strengthening may be
dispensed with.
My Invention will be fully understood by Sheet 1 of the accompanying
Drawings, which represents its application to a Cornish boiler.
Figure 1 is a horizontal section through the centre of the flue; Figures 2,

page_text: 3, and 4 are transverse sections taken respectively through the lines a, a, b, b,
and c, c, of Figure 1; Figure 5 is a perspective view of one of the water
chambers detached.
A is the flue; B, the main water space enclosing the flue, and C, the fire-
bars; D is a water bridge; E, E, are water chambers of semicircular form or
nearly so. The base line E¹ of each water chamber forms about a right angle
with the base line of the next water chamber, and all the base lines are at an
angle of about 45° with a horizontal line carried across the flue A, as is
berein-before mentioned, and as will be seen on reference to the Figures. It
will also be seen that each water chamber E fills about half the width of the
flue A, and by the alternating arrangement of the water chambers a serpentine
course is left for the products of combustion, and a clear opening F is left
along the bottom of the flue to enable a man to go through to clean or repair.
The curved edges Es of the water chambers are shown as being a short
distance from the surface of the flue, laving openings G, G, to allow the pro-
ducts of combustion to act upon as much surface as possible, and to cause the
gases to become mixed and the smoke to be consumed, but, as before
mentioned, I sometimes fill up or partly fill up some or all of these spaces G, G,
by fire-clay or otherwise. From each corner of the water chambers E, E,
I carry a short tube H to connect these chambers with the main water space B ;
these tubes H pass through holes in the flue A, and are secured by expanding
their ends in the well-known manner. The chambers E may be very readily.
cleaned through tle tubes H, and any of the chambers may be easily removed
and replaced when repair is necessary.
I do not limit myself to the exact shape of the water chambers E, as shown
in Figures 2, 8, 4, and 5, as any other shape which will act in an analogous
manner, or to suit the shape of the flues or tubes in which they are fitted may
be adopted.
Figure 5* represents by way of example a modified form of water chamber, it
may be connected to the flue at any point round the circle, and in any desired
manner. In some cases I place the water chambers E obliquely, as repre-
sented in Figures 5band. 5%, Sheet. 2.... Some of the-products of combustion
which pass along the top of the flue A, will then pass down between the
chambers E.
Another part of my Invention consists in a mode of combining flat tubes or
chambers and round or other analogous form of tubes in steam boilers, such
flat tubes and other tubes forming water chambers communicating with the
main body of water, while the flat tubes both serve as stays to the boiler
flues and as a means of causing the main portion of the products of combustion

page_text: to take a serpentine course. I place in the boiler flues vertical flat tubes or
chambers secured at top and bottom by flanges and rivets, or the tops may be
secured by flanges and rivets, and the bottoms may be expanded. These
tubes or chambers are placed alternately at opposite sides of the flue, that is
to say, one, two, or other desired number of tubes or chambers are placed at
one side extending to or beyond the centre of the flue, and then a like
number are placed at the other side of the Blue, and so on alternately at the
two sides, so as to form a clear serpentine space for the products of com-
bustion. In this serpentine space I place a number of vertical or inclined
tubes of round or similar form, which are secured in place by their ends being
expanded, or by flanges and rivets or otherwise.
In a
long boiler I leave a
clear space at each side of the flue to allow a man to pass along to clean or
repair. This part of my Invention will be understood on reference to Sheet 3.
Figure 6 is a vertical longitudinal section of a marine boiler; Figure 7 is
a horizontal section, the portion a, a, being taken through the line a, a, of
Figure 6; the portion b, b, through the line b, b, and the portion c, c, partly
through the line c, c, the remainder of this portion representing a boiler with
horizontal instead of vertical tubes. Figure 8 is a transverse section corre-
sponding to Figure 7; Figure 9 is a side view, and Figure 10 a section of
one form of flat tube or chamber which may be employed; Figures 11 and 12
and Figures 13 and 14 are similar views of other forms of flat tubes or
chambers. These forms will vary to suit the shape of the flues or smoke
passages of the boilers in which they are to be employed: These tubes or
chambers are preferably narrow at their lower ends, as shown, and these ends
are placed in straight lines with the other tubes, so as to leave a clear space
from end to end along the bottom of the flue for the purpose of allowing the
soot to be easily removed. A, A, in Figures 6, 7, and 8 are the flat tubes or
chambers placed so as to leave a serpentine space for the products of com-
bustion; B, B, are round tubes placed in this serpentine space; these tubes
have their lower ends arranged in straight rows from end to end, and their
upper ends are placed in a zig-zig manner so as to cause the flame and pro-
ducts of combustion to impinge upon as much surface as possible. These
tubes may be vertical or inclined, or some may be vertical and some inclined.
C, C, are other flat chambers or water tubes in the back smoke box at the
back end of the boiler; they can be readily cleaned, and any of them easily
taken out and replaced if required. All the tubes communicate with the
main water space. The flat tubes or chambers A and C may be narrow and
rounded at the top in the form of small short tubes as at H in Figures 11
and 13, or they may be as in Figure 9.

page_text: 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 " Improve-
ments in Steam Boilers,"-
First. The construction and arrangement of the water chambers, sub-
stantially as and for the purpose herein-before described, and as represented
in Sheets 1 and 2 of the accompanying Drawings.
Second. The arrangement of or mode of combining flat tubes and round or
other analogous form of tubes, substantially as and for the purpose herein-
before described, and as represented in Sheet 3 of the accompanying Drawings.
Third. The mode of connecting flat water chambers in steam boilers with
the main water space by means of short tubes, the ends of which are expanded
to secure the flat chambers in place, as herein-before described and represented
in the accompanying Drawings.
In witness whereof, I, the said Isaiah Kendrick, have hereunto set my
hand and seal, this Twenty-seventh day of April, One thousand
eight hundred and sixty-eight.
ISAIAH KENDRICK. (L.B.)