IMPROVEMENTS IN THE CONSTRUCTION OF STEAM BOILERS
Year: 1872

page_text: LETTERS PATENT to Edward Hammond Bentall, of Heybridge, near
Maldon, in the County of Essex, Agricultural Implement Maker,
for the Invention of "IMPROVEMENTS IN THE CONSTRUCTION OF STEAM
BOILERS."
PROVISIONAL SPECIFICATION left by the said Edward Hammond
Bentall at the Office of the Commissioners of Patents, with his
Petition, on the 6th November 1872.
I, EDWARD HAMMOND BENTALL, of Heybridge, near Maldon, in the
County of Essex, Agricultural Implement Maker, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN THE CONSTRUCTION OF
STEAM BOILERS," to be as follows:--
This Invention relates to improvements in the construction of that
class of steam boilers which is composed of sections or groups of water
spaces, which groups or sections are connected together at top and
bottom for the supply of water thereto from a main feed pipe, and for

page_text: the withdrawal of the steam for use as it is generated in the boiler. The
objects of the present Invention are to remove the difficulty hitherto
experienced from the unequal expansion of parts of the boiler, to simplify
the construction of the boiler, and to ensure an efficient circulation of
the water within the boiler.
Boilers of the class to which this Juvention refers have usually had
their sections composed of a row of vertical pipes connected together at
top and bottom by means of horizontal pipes to which they were secured
by bolts and nuts or tie rods, thus constituting a rigid or inelastic
structure. An unequal expansion of these pipes under the furnace heat
has caused great injury to the sections, and leakage of the joints has
quickly ensued. To avoid this inconvenience I construct my vertical
water and steam spaces of hollow truncated cones of cast iron set one
above the other, and having central tapped holes at top and bottom.
These cones I connect together in any given number so as to obtain the
required length of tubular water and steam space by means of screwed
collars fitting into the tapped holes of adjacent cones, and in the same
way I connect the lines of attached cones with the horizontal water and
steam pipes to form the several sections of which the boiler is to be
composed. The water and steam pipes of each section will be furnished
with tapped holes corresponding to the holes of the cones to which they
are to be attached, and a screwed collar being applied internally will
. draw the parts together. These collars are so shaped internally as to
receive a flat sided key, the turning of which will effect the fixing or
withdrawal of the collars. This arrangement is adopted for all the
internal connections of the boiler, a flanged collar being in some parts
employed to bear against a shoulder of the coupling pipe. Special
provision is made where required by the use of detachable cap pieces for
the insertion of the coupling collars, and of the keys for screwing them
into place.
The lines of attached cones besides being connected together at top
and bottom by transverse pipes to form elastic groups or sections are
connected at or about the water line with a third transverse pipe, which
pipe I carry through the brick work of the furnace, and connect it by
means of a vertical pipe with a longitudinal water supply pipe which
connects with the several sections composing the boiler by a lateral.
extension of the transverse pipes at the bottom of the sections. This
arrangement will ensure an efficient circulation of the water in the

page_text: boiler, which circulation will result from the difference of temperature
between the water spaces within and those outside of the furnace. The
transverse steam pipes are all connected with the longitudinal steam
pipe from which the steam is taken for usc.
The arrangement of the sections within the furnace may be varied to
suit varying circumstances, and the course of the flame and heated gases
through the furnace may also be varied. Baffle plates supported by the
sections will in general be used to control the course of the flame and
heated gases.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Edward Hammond Bentall in the Great Seal
Patent Office on the 6th May 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDWARD
HAMMOND BENTALL, of Heybridge, near Maldon, in the County of
Essex, Agricultural Implement Maker, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Sixth day of November, in the year of our
Lord One thousand eight hundred and seventy-two, in the thirty-sixth
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said Edward Hammond Bentall, Her special licence
that I, the said Edward Hammond Bentall, my executors, adminis-
trators; and assigns, or such others as I, the said Edward Hammond
Bentall, 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
"IMPROVEMENTS IN THE CONSTRUCTION OF STEAM BOILERS," upon the condition
(amongst others) that I, the said Edward Hammond Bentall, my
executors or administrators, by an instrument in writing under
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.

page_text: NOW KNOW YE, that I, the said Edward Hammond Bentall, 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, reference being had to the Drawings
hereunto annexed, and to the letters and figures marked thereon (that is
to say):
This Invention relates to improvements in the construction of that
class of steam boilers which is composed of sections or groups of water
spaces, which groups or sections are connected together at top and
bottom for the supply of water thereto from a main feed pipe, and for
the withdrawal of the steam for use as it is generated in the boiler. The
objects of the present Invention are to remove the difficulties hitherto
experienced from the unequal expansion of parts of the boiler, to
simplify the construction of the boiler, and to ensure an efficient
circulation of the water within the boiler.
Boilers of the class to which this Invention refers have usually had
their sections composed of a row of vertical pipes connected together at
top and bottom by means of horizontal pipes to which they were secured
by bolts and nuts or tie rods, thus constituting a rigid or inelastic
structure. An unequal expansion of these pipes under the furnace heat
has caused great injury to the sections, and leakage of the joints has
quickly ensued. To avoid this inconvenience I construct my vertical
water and steam spaces of hollow truncated cones of cast iron set one
above the other, and having central tapped holes at their top and bottom
ends. These cones I connect together in any given number so as to
obtain the required length of tubular water and steam space by means of
screwed collars fitting into the tapped holes of adjacent cones, and in
the same way
I connect the lines of attached cones with the horizontal
water and steam pipes to form the several sections of which the boiler is
to be composed. The water and steam pipes of each section will be
furnished with tapped holes corresponding to the holes of the cones to
which they are to be attached, and a screwed collar being applied
internally will draw the parts together. These collars are so shaped
internally as to receive a flat sided key, the turning of which will effect
the fixing or withdrawal of the collars. This arrangement is adapted for
all the internal connections. of the boiler, a flanged collar being in some
parts employed to bear against a shoulder of the coupling pipe. Special
provision is made where required by the use of detachable cap picces for

page_text: them into place.
The lines of attached cones, besides being connected together at top
and bottom by transverse pipes to form elastic groups or sections, are
connected a little above the water line with a third transverse pipe,
which pipe I carry through the brickwork of the furnace, and connect by
means of a vertical pipe with a longitudinal water supply pipe which
connects with the several sections composing the boiler by a lateral
extension of the transverse pipes at the bottom of the sections. This
arrangement will ensure an efficient circulation of the water in the boiler,
which circulation will result from the difference of temperature between
the water spaces within and those outside of the furnace. The trans-
verse steam pipes are all connected with the longitudinal steam pipe,
from which the steam is taken for use.
The arrangement of the sections within the furnace may be varied to
suit varying circumstances, and the course of the flame and heated gases
through the furnace may also be varied. Baffle plates, supported by the
sections, will, in general, be used to control the course of the flame and
heated gases.
The construction of my improved cone boiler having been described in
general terms, I will now proceed to explain, with reference to the
accompanying Drawings, such details of the various parts as will enable
any competent mechanic to construct and set up the improved boiler.
In Sheet I. of the Drawings Fig. 1 shews, in longitudinal sectional
elevation, the cone boiler set up in a furnace; Fig. 2 is a sectional plan of
the same taken in the line 1, 2, of Fig. 1; Fig. 3 is a transverse vertical
section taken in the line 3, 4, of Fig. 1.
In Sheet II. Fig. 4 is a side elevation of the boiler and furnace; and
Fig. 5 is a plan or top view of the same; the other Figures in this Sheet
are enlarged details of parts, and will be specially referred to hereafter.
..
The sections of the boiler consist of any desired number of rows of
vertical tubes A, composed each of a series of hollow truncated cones a
set one above another, and firmly connected together; such rows A
being connected together at bottom by a tranverse pipe B, at a little
below the water level by a transverse pipe C, and at top by a transverse
pipe D.
The transverse pipes B, C, and D of cach section all project.

page_text: through the brickwork of the furnace. The pipes B I connect, with
a longitudinal pipe E, external of the furnace, which pipe serves to
supply water to all the sections. Pendent from each pipe C is a pipe F
which connects through the water supply pipe E with the pipe B of its
section, and near the top of the furnace is a longitudinal pipe G which
connects with all the pipes D, and is intended to lead off the steam from
all the sections. The vertical pipes F, external of the furnace, will, by
reason of their bringing into direct connection the hottest and coldest
parts of the boiler, ensure a rapid circulation of the water through the
sections, and the peculiar configuration of the vertical tubes A will com-
pensate for irregularities in the cooling of the metal; H are baffle plates
for causing the flame and heated gases to traverse to and fro through
the furnace in their passage to the chimney.
The cones a, a, (see the enlarged sectional view, Fig. 6) are tapped at
their upper and lower ends to receive a screwed collar a', the opening
through which is made hexagonal, as shewn at Fig. 6 for the insertion
of a key for turning it. These screwed collars serve to connect the cones
together, and as they are all in line, and if access is provided at the top
for the insertion of a key the compound structure shewn at Fig. 6 may
be readily separated into parts for the purpose of removing and replacing
any injured or defective portion. The transverse pipe D is made with a
cover d, which is secured in place by nuts and bolts, and at its under
side it is provided with holes which correspond with the terminations of
the compound tubes A, which holes are intended to receive a flanged
screw collar a², shewn detached at Fig. 6, for connecting the pipe D and
tube A together. It will now be understood that suppose it be required
to detach the parts shewn at Fig. 6 it will only be necessary to remove
the cover d, and the key may then be admitted to withdraw first the
collar a² from its socket and then the collars a¹ in succession.
The pipe C, Fig. 6, it will be seen is secured to the cones a by a
screwed collar a¹ and a flanged screwed collar a³, which latter must be
introduced to its seat through the end of the pipe. The pipe B is fitted
with a screw plug bat bottom in a line with the axis of the attached
tube A; this is for the purpose of gaining access to the interior in an
upward direction for cleaning. The transverse pipes D (see the enlarged
sectional views, Figures 7 and 8,) which connect with the steam pipe G
are tapped to receive screwed flanged collars a², and to allow of the
insertion of the collars and of their being screwed in place openings

page_text: are made on the opposite side of the pipe G; these openings are closed by
cap picces g. The pipes C (see Fig. 9) are severally connected with
their respective pipes F by means of screwed flanged collars a³, and these
pipes F are like the steam pipe G provided with an opening for the
insertion of the screwed collar and for a key for screwing it into place.
A cap serves to cover the opening, through which the collar is
admitted.
The lower ends of the pipes F (see Fig. 10) are similarly secured to the
water pipe E, openings being made in the pipes F in the line of the
connection for the admission and insertion of the flanged screw collars.
These openings are covered by cap pieces f¹. The transverse water pipe
B is connected with the longitudinal water pipe E, also by flanged screw
collars a, and it is to allow of the admission of these collars into the
pipe E that the screwed sockets, which receive the collars, which couple
the pipes E and F together, are enlarged, as shewn in the Figure.
The relative proportions of the two sizes of flanged collars used in
connection with the pipe E is clearly shewn at Figures 10°.
Having now set forth the nature of my Invention of " Improvements
in the Construction of Steam Boilers," and explained the manner of
carrying the same into effect, I wish it to be understood that under the
above in part recited Letters Patent I claim, constructing tubular boilers
in the manner and for the purpose above described.
In witness whereof, I, the said Edward Hammond Bentall, have
hereunto set my hand and seal, the Fifth day of May, in the
year of our Lord One thousand eight hundred and seventy-three.
E. H. BENTALL.. (L.S.)