Improvements in Tubulous Steam Boilers
Year: 1897

page_text: Date of Application, 19th Nov., 1897-Accepted, 24th Dec.,
1897
COMPLETE SPECIFICATION.
66
Improvements in Tubulous Steam Boilers."
(A Communication from abroad by the SOCIÉTÉ ANONYME DU TEMPLE of Paris in
the French Republic.)
I, PHILIP MIDDLETON JUSTICE, of 55 and 56 Chancery Lane, in the County of
London, Chartered Patent Agent, do hereby declare the nature of this invention
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement: -
This invention relates to certain improvements in tubulous steam boilers with
so called accelerated circulation, and is more especially applicable to boilers, in
which the passage of the gases across the system or group of tubes is a horizontal
one.
The object of this invention is to more completely reduce the temperature of the
gases, resulting from the combustion, previous to their discharge into the atmos-
phere. An amount of heat is thus economized which enables a higher percentage
of steam per kilogramme of fuel to be generated. The fuel employed, may be of
a solid, liquid or gaseous nature.
For this purpose the least heated portion of the group of tubes is so arranged
as to ensure a methodical and forced circulation of the feed-water previous to its
arrival in the boiler proper. This portion of the group or system of tubes thus
plays the part of a feed water heater, in which the water is gradually raised to a
temperature as near as possible to that in the lower or cooler steam and water drum,
remaining however, lower than the latter.
The accompanying drawing represents a boiler of the above kind provided with
the improvement in question.
In this drawing, Fig. 1 represents a longitudinal elevation of a boiler, the part
in section being principally that which forms the subject of this invention.
Fig. 2 is a cross section of the boiler the left hand side showing the vaporizing
group of tubes V while the right hand side shows the feed-water heating group of
tubes R the latter being at the firing end while the former are at the far end so
that the section it will be seen is not taken on the same plane.
Fig. 3 is a half plan on the line MN Fig. 2.
As will be seen each group of tubes comprises two parts:
One V, or the vaporizing part which performs the usual office of the tubes
employed in ordinary boilers. It comprises the most highly heated tubes and
including those which form the vault of the fireplace or furnace, being the inside
close row or wall indicated by the letter a.
The other part R, or feed water heating group is situated at the chimney end
which is also the firing end and in the type of boiler shown is the least heated
portion and may be formed of tubes of the same diameter and metal as the group V
or otherwise. It is protected from the immediate heat of the fire by the close
row a before mentioned. The tubes of the group V terminate above and below in
removeable chambers b, b', formed by suitable partitions carried by the drums AB
at one end. These chambers are so partitioned that each molecule of water intro-

page_text: duced in the bottom chamber 61 is compelled to circulate through the tubes of the
group R as shown by the arrows Fig. 1 before it is discharged into the drum A.
In the drawing, the feed-water passing through the valve r at a pressure which
is slightly higher than that existing in the boiler, is not able to flow into the
steam chest A through the pipe p until having completed seven ascending and
descending passages in the interior of the feed-water heating set such group of
seven being shown on one side of Fig. 3 as consisting of four tubes w in each group.
It may be desirable to increase the number of these in order to accelerate the
circulation. The transmission of the heat is thus improved, while avoiding the
formation of disturbing counter-currents in the interior of the groups of tubes.
During these movements the feed-water absorbs from the hot gases a certain
quantity of their excessive heat and does not reach the vaporizing group, until
having been raised to a comparatively high temperature.
The blow-off cocks a, a¹, a¹¹, all, serve for the removal of the sediment which
may accumulate at the lower part of the chamber b¹.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:
1. In tubulous steam boilers the arrangement of a portion or group of the tube
connecting the drums or collectors as a feed water heater into which the water
is first passed and through which it circulates before reaching the vaporizer por-
tion or group of tubes such feed water group being situated at the least heated
part of the boiler or being suitably protected from the greatest. heat substantially
as and for the purpose described.
2. In tubulous steam boilers of the type illustrated the arrangement of a portion
of the group of tubes as a feed water heater such group being connected with
removable chambers formed in the upper and lower drums and in which group
the water is first passed and through which it circulates before reaching the
vaporizing portion such feed water group being situated at the least heated part
of the boiler substantially as and for the purpose described.
3. The improvement in tubulous steam boilers substantially as and for the
purpose described and illustrated in the accompanying drawing.
Dated this 19th day of November 1897.