IMPROVEMENTS IN STEAM BOILERS
Year: 1876

page_text: LETTERS PATENT to Hunter Henry Murdoch, of No. 7, Staple Inn, in the
County of Middlesex, Patent Agent, for the Invention of "IMPROVEMENTS IN
STEAM BOILERS." A communication from abroad by Emile Béde, of Verviers,
in the Kingdom of Belgium. Engineer.
PROVISIONAL SPECIFICATION left by the said Hunter Henry Murdoch at the
Office of the Commissioners of Patents on the 20th September 1876.
HUNTER HENRY MURDOCH, of No. 7, Staple Inn, in the County of Middlesex,
Patent Agent.
"IMPROVEMENTS IN STEAM BOILERS."
This Invention relates to an improved construction of tubular steam boilers in
which the water is caused to circulate rapidly, and a large heating surface is
obtained, and other advantages are realized.
The shell of the said boiler is formed of two semi-cylindrical or nearly semi-
cylindrical portions disposed horizontally one above the other and connected together
by straight or flat vertical or nearly vertical sides.
The middle of the said boiler is traversed longitudinally by a horizontal case or
chest of rectangular section containing vertical tubes. The plain or flat sides of the
boiler and those of the case or chest are strongly stayed together so that the pressure
of the steam on the two sides is counterbalanced. The other parts of the body or
sbell of the boiler being portions of cylinders are not liable to change their form and
do not require to be stayed. The upper and lower sides of the tube case or chest
are stayed together by the tubes themselves, which are fixed at both ends.
The furnaces may be internal or external. The brickwork and flues of the boiler
are arranged so that the flames issuing from the back of the furnaces pass through
the tube box, impinging upon the surface of the tubes therein, and return along the
sides of the boiler to the chimney.
The height of the boiler space above the tubes being sufficient to allow of the

page_text: removal of the tubes, also allows suitable tools to be introduced into the tubes so as
to cleanse them with facility.
In some cases the flat stayed sides of the boiler are replaced by two rows of tubes,
the said tubes having plates affixed to them so as to form with the said tubes the
sides of the boiler.
Boilers constructed according to this modification of the Invention when dis-
mounted, may be transported in several pieces to the place where they are to be set
up, and there may be mounted without difficulty as when the smoke boxes at the
front and back of the boiler are placed in the position they occupied before the
respective portions of the boiler were taken apart, the upper and lower parts of the
shell will necessarily occupy their exact position. These two parts may also be
connected together by several vertical tubes on the sides of the boiler by which the
circulation of the water is promoted and the cleansing of the boiler still more easily
effected.
For very high pressures it is necessary to make the upper portion of the shell of
comparatively small diameter. In that case suitable holes closed by covers are made
in it for the purpose of introducing and cleansing the tubes.
In consequence of the great circulation of water the cleansing of the tubes is very
seldom necessary. It can when necessary be effected without opening the covers if
the diameter of the shell be sufficient for a man to introduce into the tubes a brush
hanging to a chain.
For very high pressures boilers of any size may be made by connecting together
side by side several boilers constructed with small shells with the furnace between
them
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Hunter Henry Murdoch in the Great Seal Patent Office on the 19th
March 1877.
HUNTER HENRY MURDOCH, of No. 7, Staple Inn, in the County of Middlesex,
Patent Agent. "IMPROVEMENTS IN STEAM BOILERS." A communication from abroad
by Emile Bède, of Verviers, in the Kingdom of Belgium, Engineer.
This Invention relates to an improved construction of tubular steam boilers in
which the water is caused to circulate rapidly, and a large heating surface is
obtained, and other advantages are realised.
The shell of the said boilers is formed of two semi-cylindrical or nearly cylindrical
portions disposed horizontally one above the other and connected together by
straight or flat vertical or nearly vertical sides.
The middle of the said boiler is traversed longitudinally by a horizontal case or
chest of rectangular section containing vertical tubes. The plain or flat sides of the
boiler and those of the case or chest are strongly stayed together so that the pressure
of the steam on the two sides is counterbalanced. The other parts of the body or
shell of the boiler being portions of cylinders are not liable to change their form and
do not require to be stayed. The upper and lower sides of the tube case or chest are
stayed together by the tubes themselves, which are fixed at both ends.
The furnace or furnaces is or are internal. The brickwork and flues of the boiler
are arranged so that the flames issuing from the back of the furnaces pass through
the tube box impinging upon the surface of the tubes therein, and return along the
sides of the boiler to the chimney.
The height of the boiler space above the tubes being sufficient to allow of the
removal of the tubes, also allows suitable tools to be introduced into the tubes so as
to cleanse them with facility.
In some cases the flat stayed sides of the boiler are replaced by two rows of tubes,

page_text: the said tubes having platos affixed to them so as to form with the said tubes the
sides of the boiler.
Boilers constructed according to this modification of the Invention, when dis-
mounted may be transported in several pieces to the place where they are to be set
up and there they may be mounted without difficulty as when the smoke boxes at
the front and back of the boiler are placed in the position they occupied before the
respective portions of the boiler were taken apart, the upper and lower parts of the
shell will necessarily occupy their exact position. These two parts may also be
connected together by several vertical tubes on the sides of the boiler by which
means the circulation of the water is promoted and the cleansing of the boiler is still
more easily effected.
For very high pressures it is necessary to make the upper portion of the shell of
comparatively small diameter. In that case suitable holes closed by covers are made
in it for the purpose of introducing and cleansing the tubes.
In consequence of the great circulation of water the cleansing of the tubes is very
seldom necessary. It can when necessary be effected without opening the covers if
the diameter of the shell be sufficient for a man to introduce into the tubes a brush
hanging to a chain.
For very high pressures boilers of any size may be made by connecting together
side by side several boilers constructed with small shells with the furnaces between
them.
Having now explained the nature of the said Invention, I will proceed to describe
with reference to the accompanying Drawings the manner in which the same may
be performed.
Figures 1, 2, 3, and 4, of the accompanying Drawings represent a steam boiler con-
structed according to this Invention; Figure 1 is a transverse vertical section of the
said boiler mounted in position; Figure 2 is a vertical longitudinal section of the
same; Figure 3 is a horizontal section of the same; and Figure 4 is a front elevation
of the same.
The same letters of reference indicate the same parts in all the said Figures.
A, B, C, D, is the shell of the boiler, each of the two parts A, C, being nearly two
thirds of a cylinder; the said parts A, C, of the shell are connected together by the
flat vertical sides B and D. The front and back A¹, C1, A2, C3, of the boiler are flat.
The under part A of the boiler is traversed throughout its length by two longi-
tudinal furnaces F, F¹, (in some cases a single furnace is used) and above the said
furnaces and between the portions of cylinders A, C, the boiler is traversed through-
out its whole length by a rectangular case or chest G, H, I, K, open at each end, in
which is affixed a series of rows of vertical tubes T.
The tubes in the two rows next to each side of the case or chest G, H, I, K, are
connected to the upper and lower parts G, I, by simply forcing their ends which
are slightly tapered into tapering holes in the said plates. This arrangement allows
of the said tubes may being easily removed when it is necessary to inspect or repair
the side plates H, K, of the chest or case. The said plates H, K, are firmly stayed to
the side plates B, D, of the boiler, as shown in Figures 1 and 3; other suitable stays
are affixed to different parts of the shell of the boiler, so as to strengthen the parts
thereof where necessary. Two man-holes L, L¹, in the under part of the boiler and
a man-hole L³ in its upper part give access to all parts of the boiler. The height of
the upper part C or steam chamber is sufficient to allow of the tubes T being drawn
up out of the case or chest G, H, I, K, or of a suitable tool being inserted into the
said tubes to cleanse them; should the water be so hard that the action of the steam
does not suffice to keep them clean, P is a rectangular frame or cover which encloses
the front end of the case or chest G, H, I, K, and side flues of the boiler forming a
channel or passage for the products of combustion issuing from the said case or chest.
In the said frame or cover P are two doors P1, P2, giving access to the tubes T so as
to allow of the outside of the tubes being cleaned. The brickwork in which the
said boiler is mounted is arranged so as to cause the flames and products of combus-
tion from the two furnaces to unite in a flue or chamber at the back of the boiler,

page_text: and afterwards to pass upwards, and through the case or chest G, H, I, K, where
they impinge upon the tubes T, and then entering the space within the frame or
cover P to return through flues on the sides of the boiler, and thence to escape to
the chimney.
In marine boilers the chamber or flue receiving the flames and products of com-
bustion from the furnaces is made inside the boiler, as is usual, and the products of
combustion may be made to pass off directly to the chimney from the frame or
cover P, Figure 2, or to return to the chimney by passing along the sides of the
boiler through suitable flues, or when several boilers are used side by side, the
products of combustion may be made to pass between the said boilers.
For very large boilers the carriage of which would be two difficult if constructed
as herein-before described, for the flat sides B, D, of the shell and H, K, of the tube
case or chest may be substituted two rows of tubes between which iron plates are
affixed. The said tubes and plates form the side flues of the boiler by which the
products of combustion are made to return after passing through the tube case or
chest, two frames or covers of the character of the frame or cover P, represented in
the accompanying Drawings, being used one at the front and the other at the back
of the boiler.
Figure 5 represents in plan partly in section, and Figure 6 represents in side
elevation portions of tubes and the plates by which they are fixed in position accord-
ing to this arrangement. T,T, are the tubes which are held between the plates t¹,t, t2, t²,
by means of screw bolts ³, ts, and nuts t, t. If the boiler have been taken to pieces
and it is required to put it together again, the said frames or covers will serve as
bench marks. In this arrangement of the boiler the tubes may be forced into
position after the boiler is mounted as no necessity to remove them is to be foreseen,
suitable stays are used to prevent the separation of the two parts of the boiler, and
the bending of the plates. By the several arrangements of the boiler herein-before
described, the following results are obtained.
The steam generated by the tubes and by the furnaces being obliged to pass
through the tubes in large quantities, the density of the liquid, half steam and half
water in the tubes, is much inferior to that of the water between the flat sides
of the boiler and tube chest where the evaporation is much less intense. This
difference of density gives rise to a very rapid circulation which cleanses the tubes,
the upper part of the furnaces and the tube chest or case thus preventing the
incrustation of such parts of the boiler. The steam rising from any of the boiler
being obliged to pass through the tubes or the spaces between the flat sides of
the shell and tube chest is well divided over the whole surface of the water, thus
preventing violent ebullition only at some parts of the boiler, and priming is avoided
in consequence both of this well divided ebullition of the large size and height
of the steam chamber.
The amount of heating surface is very large and well divided in a very small
врасе.
The passages for the flames may be made as large as required, and the flames not
being so much divided as in other tubular boilers, are not extinguished as rapidly
and the combustion is more perfect. The cleansing of the said passages may be
speedily effected by means of a jet of steam.
The water level being made from five to seven feet (according to the size of the
boiler) above the upper parts of the furnaces, the feed of water into the boiler might
be stopped for six hours or more before the furnaces would cease to be covered with
water. Such a stoppage of the feed would perhaps give rise to some leakage easy
to repair, but no explosion would take place.
Having now explained the nature of the said Invention and the means pursued
in carrying the same into effect, I wish it to be understood that I do not confine myself
to the precise details herein-before described and illustrated in the accompanying
Drawinge, as such details may be varied without departing from the nature of the
said Invention; but I claim as the said Invention, the combination and arrangement
of parts of steam boilers herein-before described and illustrated in the accompanying

page_text: Drawings, that is to say, constructing boilers with upper and lower chambers con-
nected by tubes, and with furnaces in the lower chamber, the relative arrangement
of the parts being such as to cause the steain generated in the lower chamber to
pass through the said tubes to the upper chamber essentially as described.
In witness whereof, I, the said Hunter Henry Murdoch have hereunto set my
hand and seal, this Nineteenth day of March, in the year of our Lord One
thousand eight hundred and seventy-seven.
Witness,
W. T. WHITEMAN,
H. H. MURDOCH. (L.S.)