IMPROVEMENTS IN THE CONSTRUCTION OF MULTITUBULAR STEAM BOILERS
Year: 1875

page_text: LETTERS PATENT to Benjamin Joseph Barnard Mills, of the Firm of
Harris and Mills, of 23, Southampton Buildings, in the County of
Middlesex, Patent Agent, for the Invention of "IMPROVEMENTS IN
THE CONSTRUCTION OF MULTITUBULAR STEAM BOILERS."-A communication
from abroad by Messieurs De Naeyer and Company, Manufacturers,
of Brussels in the Kingdom of Belgium.
PROVISIONAL SPECIFICATION left by the said Benjamin Joseph
Barnard Mills at the Office of the Commissioners of Patents, with
his Pétition, on the 3rd July 1875.
I, BENJAMIN JOSEPH BARNARD MILLS, of the Firm of Harris and
Mills, of 23, Southampton Buildings, in the County of Middlesex,
Patent Agent, " IMPROVEMENTS IN THE CONSTRUCTION OF MULTITUBULAR STEAM
BOILERS, a communication to me from abroad by Messieurs De Naeyer
and Company, Manufacturers, of Brussels, in the Kingdom of Belgium,
to be as follows:-
"
The boiler is composed of a greater or smaller number of tubes placed

page_text: above a furnace, and arranged in rows so that the tubes of the upper
rows shall come over the spaces between those of the lower rows.
The arrangement of the boxes herein-after described is such as to
permit of only a small space being left between the tubes, which causes
the products of combustion to give off more readily their heat than
when the tubes are more widely separated from cach other. The tubes
are connected together into "elements" of two by means of cast-iron
boxes.
In order to avoid joints and couplings the boxes are tapped with right
and left hand screw threads. The mounting or forming of two tubes
into an "element" is effected by connecting at the same time two tubes
in two boxes. The screw threads being right and left the tubes are fixed
simultaneously in the two boxes by turning them by means of strong
tongs, one of the boxes being held firmly in a vice. The tubes thus
connected together in pairs or " elements are placed in rows one abovo
another, taking care to place each of the upper rows of tubes over a
space between the tubes of the lower rows. In arranging them in this
manner a small space will be left in each row which will serve for
sighting, and by which, aided by a jet of steam, the soot which collects
on the tubes is removed.
"
Towards the lower and front part of each box, and in front of each of
the tubes, is a smaller hole. In this hole is screwed one end of a
wrought-iron tube, the other end of which is made of a conical form to
fit a corresponding conical recess in a cast-iron connection forming a
communication between a tube of an upper row and a tube of a lower
row. This detail should be very carefully prepared in order to ensure
a tight joint. The pieces effecting the communication between two
" elements are held in position by means of stirrups or cross bars, each
of which is fixed by a nut to a bolt tapped into one of the boxes.
"
The feeding is effected through a tube placed at the lower and back
part of the boiler whilst the steam is collected in a reservoir or chamber
placed in front and at the upper part of the boiler.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Benjamin Joseph Barnard Mills in the Great
Seal Patent Office on the 3rd January 1876.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, BENJAMIN
JOSEPH BARNARD MILLS, of the Firm of Harris and Mills, of 23,
Southampton Buildings, in the County of Middlesex, Patent Agent,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Third day of July, in the year of our
Lord One thousand eight hundred and seventy-five, in the thirty-
ninth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Benjamin Joseph Barnard Mills, Her
special license that I, the said Benjamin Joseph Barnard Mills, my
executors, administrators, and assigns, or such others as I, the said
Benjamin Joseph Barnard Mills, 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
MULTITUBULAR STRAM BOILERS," a communication to me from abroad by
Messieurs De Naeyer and Company, Manufacturers, of Brussels, in the
Kingdom of Belgium, upon the condition (amongst others) that I, the
said Benjamin Joseph Barnard Mills, 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 Benjamin Joseph Barnard Mills, do
hereby declare the nature of the 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, and to the figures and letters marked
thereon:-
11aumbox of tuban D

page_text: placed above a furnace, and arranged in rows so that the tubes of the
upper rows shall come over the spaces between those of the lower rows,
as represented at Figure 1.
The arrangement of the connecting boxes A, herein-after described, is
such as to permit of only a small space being left between the tubes B,
which causes the products of combustion to give off more readily their
heat than when the tubes are more widely separated from each other. The
tubes B are slightly inclined towards the back, and communicate with
each other at the front and back by means of a connecting piece or
coupling C, D. The tubes B are connected together into pairs or
"elements" of two by means of cast-iron boxes A.
In order to avoid the use of ordinary union joints and couplings the
boxes are tapped with right and left hand screw threads. The mounting
or forming of two tubes B into an "element" is effected, as shown by
Figure III., by connecting at the sane time two tubes B with two
boxes A. The screw threads being right and left handed the tubes B
are fixed simultaneously in the two boxes A. by turning them by means
of strong tongs, one of the boxes being held firmly in a vice. The
tubes B being thus connected together into pairs or "elements" of two
are placed in rows one above another, taking care to place each of the
upper rows of tubes over a space between the tubes of the lower rows.
In arranging them in this manner a small space will be left in each row.
This space or opening will serve for sighting, and by it, aided by a jet of
steam, the soot which collects on the tubes may be removed.
Figure IV. represents the elevation of a connecting box A on the side
of the tubes B, and Figure V. represents the elevation of a connecting
box A on the side of the connecting pieces or couplings C, D.
Towards the lower and front part of each box A, and in front of each
of the large tubes B, is a smaller hole, which is shown at Figures V., VI.,
and VII. Into this hole is screwed one end of a wrought-iron tube C,
the other end of which is made on the exterior thereof of a conical form
to fit a corresponding conical recess in a cast-iron connection or
coupling D, forming a communication between a tube B of an upper
row and a tube B of a lower row. This detail should be very carefully
prepared or attended to in order to ensure a tight joint. The connecting
piece D effecting the communication between two elements or pairs
of tubes is held in position by means of a stirrup or cross bar E fixed

page_text: by a nut to a bolt F, which is tapped or screwed into one of the
boxes A'.
"
The part O is made of wrought iron, in order to afford the elasticity
necessary to form a perfect joint.
By means of these arrangements the building up of the boiler is very
simple and very expeditious, and when it is required to replace a tube it
is only necessary to remove a single "element" or pair of tubes B..
As above mentioned the small tubes C, C, being placed in face of the
tubes B of the boiler it is only necessary to remove the connecting
pieces D to enable the interior of the tubes B to be cleaned.
1
The feeding is effected through a tube K placed at the lower and
back part of the boiler, whilst the steam is collected in a reservoir or
chamber L placed in front and at the upper part of the boiler.
"
In place of screwing the end of the tube C into the cast-iron box A
the screw e may be dispensed with, and similar conical joints to those
which connect the connecting pieces D to the tubes C may be employed
in lieu thereof, as represented at Figure VIII. In short, as indicated at
Figure VIII, the small tube O may have its two ends on the exterior
thereof turned to a conical form, and in the box A corresponding conical
recesses may be made. The apparatus thus modified is more easily and
expeditiously put together. And again, as indicated at Figure IX., the
small tubes C may be dispensed with, and the male conicity may
be given to the connecting pieces D, and the female conicity to the
holes in the boxes A. In this case malleable cast iron will be.
employed in the construction of the connecting pieces D to secure
greater elasticity. The means have also been found of obviating the use
of ordinary union joints and couplings by screwing the boxes and the
tubes with right and left handed screw threads, and by connecting
together simultaneously two tubes B and two boxes A. Further, the
application of the conical precise fitting joint has been extended to the
coupling together of the tubes B and boxes A, and the results obtained
have determined the Inventor to adopt this system.
In lieu of providing the ends of the tubes B and the holes in the
boxes A with screw threads they may each be turned with a conicity
corresponding to each other, as shown at Figure X. The union or
coupling is effected with great facility by means of long bolts and
clamping pieces or tie rods.

page_text: In order to obviate the danger of a possible separation of these parts
from each other when the boiler is in use the tubes B are fixed to the
boxes A by three or other number of screwed studs a, see Figures X.
and XI.
Having thus described the nature of the said Invention, and the pre-
ferred modes in which the same may be carried into effect, I would have
it understood that what I claim is, the construction of multitubular
steam boilers by connecting the tubes B into pairs or "elements" of two
by means of boxes A, and effecting the intercommunication of the pairs
of tubes or "elements" by means of connecting pieces D, all con-
structed, arranged, and combined in manner substantially as herein
shown and described, whereby the employment of india-rubber or other
packing in the connections or couplings is dispensed with.
In witness whereof, I, the said Benjamin Joseph Barnard Mills,
have hercunto set my hand and seal, this First day of January,
in the year of our Lord One thousand eight hundred and seventy-
six.
E