Improvements in Multitubular Steam Boilers.
Year: 1890

page_text: COMPLETE SPECIFICATION.
Improvements in Multitubular Steam Boilers.
I PIERRE RAYMOND CODY of Graville Sainte Honorine, France Engineer do
hereby declare the nature of this invention and in what manner tho same is
to be performed, to be particularly described and ascertained in and by the
following statement :-
The employment of high pressures in steam-engines of all kinds, notably in the
double and triple expansion engines adopted in marine engineering conduces to a
considerable increase in the weight of the boilers in consequence of the increase in
thickness which it is necessary to give to the metal in all the parts which have to
resist these high pressures.
It has with reason been hoped that by the adoption of tubular surfaces it would be
possible to obtain boilers of small weight and at the same time of small size and
capable of withstanding high pressures. The exhibition held at Paris in 1889 has
furnished proof of the efforts which have been made towards this end but it is not
shown that a production desirable as an economic manufacture or for practical use
and maintenance has been arrived at.
Now consider as indispensable for advantageous service under all circumstances
that a boiler should fulfil the following essential conditions:-
1st. It should be of small weight and of small size this condition being rendered
easy of fulfilment by the employment of tubes.
2nd. The apparatus should be simple so as to permit inspection, taking to pieces,
repairs and easy management.
3rd. The heating surfaces should be arranged in such manner as to utilize the
greatest possible amount of the direct radiant heat from the fuel on the grate.
4th. A mechanical circulation of the water in the tubes should be ensured so that
continually renewed water shall be presented to the radiation from the fuel on the
grate so that the heat shall be promptly or quickly absorbed.
5th. The disengagement of the steam should be facilitated by a
sufficiently large and heated and well protected so that "dry steam
obtained.
"
reservoir
may be
The system of multitubular boiler which I have invented and which forms the
subject of the present application is intended to fulfil the different conditions above
mentioned. The special arrangements in which my improved boiler consists may
be ascertained by reference to the accompanying drawing which represents, by way
of example, a boiler constructed according to my invention and to which the detailed
description following refers.
In the accompanying drawing Fig. 1 is a longitudinal section taken through one of
the groups or bundles of tubes employed in the boiler, Fig. 2 is a transverso section
taken on the line 1, 2 of Fig. 1, Fig. 3 is a plan with a part in section so that one of
the said groups or bundles of tubes may be shown and Fig. 4 is a view showing in
one half the front of the boiler and in the other half the back of the boiler, the portion
to the left of the centre line of the figure showing the front of the boiler and the
portion to the right of the centre line of the figure showing the back of the
boiler. The boiler illustrated in the said figures is more especially intended for
use in a torpedo boat.
Speaking generally this boiler has above an ordinary grate H, two cylindrical,
groups or bundles of inclined tubes V ending in boxes A, A, and B, B, situate some
at the back of the boiler and the others at the front thereof which cylindrical groups
or bundles of inclined tubes communicate in common with an upper steam
reservoir G, G. These two cylindrical groups or bundles of inclined tubes are

page_text: surrounded laterally by two partitions I, I, formed of tubes and at their two
extremities by partitions J, J, formed of metal plates lined with firebrick or other
like material.
T
When in operation the two groups or bundles of tubes which are the principal
organs of the boiler constructed on this system have imparted to them a movement
of rotation variable with the degree of activity of the furnace. When the furnace is
in full activity the rotation should be from about three to four turns per minute so
that the surface exposed to the radiation from the fuel on the grate may be renewed
or changed from six to eight times per minute. In order that this movement of
rotation may be produced each group or bundle of tubes V is provided at the front of
the boiler with a worn-wheel T into which gears a worm S formed or secured upon a
shaft U driven by a small special motor which in the case of a torpedo boat may be
the ventilating engine the speed of which modifies and governs the activity of the
furnace as may be required. The worms S, S, are arranged in such manner that the
two groups or bundles of tubes may turn in contrary directions. Any other method
of imparting motion to the said groups or bundles of tubes may be employed as the
method indicated on the drawing is only shown by way of example.
Having thus indicated the general arrangement of my improved boiler I will now
proceed to refer to the details of the arrangement.
The boxes A, A, serve for the "feeding" of the groups or bundles of tubes with
water and the boxes B, B, serve for the disengagement of the steam. The boxes A, A,
communicate by means of the tubes C, C, and pipe P, with the upper reservoir G, G,
with which the boxes B, B, communicate by means of the tubes D, D, and the pipe Q.
The tubes C, D, are fixed; stuffing boxes E, F, or other suitable appliances being
provided in order to allow the rotation of the groups or hundles of tubes V, V, to
take place. The tabes D, D, are provided with water gauges. The mean level of
the water in the groups or bundles of tubes is indicated by the line a,, (Fig. 1).
The tubos of the partitions I, I, start from the lower reservoirs L, L, and terminato
in the sides of the upper reservoir G, G. The reservoirs L, L, communicate with the
tubes C, C, by means of the pipes R, R. Water is supplied to the boiler at X in any
suitable manner and the level of the water is generally at a, y. The reservoirs L, L,
are of use in certain cases on board ships. On account of rolling or other circum-
stances it may be necessary in boilers for use on shipboard to raise the level of the
water in the partitions 1, I, of tubes as indicated by the dotted lines a¹ y' in which
case the feed water" is supplied at X rises in the tubes forming the partitions I, I,
passes through the upper reservoir G, G, and descends into the groups or bundles of
tubes V, V, by means of the pipe P and the tubes C, C. In this case the pipe P
penetrates as indicated by dotted lines into the upper reservoir to the extent P¹ by
which it is desired to raise the level of the water in the reservoir and in consoquence
in the partitions 1, I, of tubes, and the pipes R, R, are dispensed with the lower
reservoirs being placed in intercommunication by means of a pipe R' situate behind
the boiler.
The steam produced in the boiler is taken out of the upper reservoir G, G,
at Y.
The casing of the boiler is formed, partly, of two iron partitions J, J, which are
furnished with fire bricks or other like refractory materials and are provided with the
various circular openings required for the passage of the groups or bundles of
tubes V, V, and steam reservoir G, G, and with the door of the furnace and, partly,
of the double casing M which is lined with amianthus or like material and on the
sides of the boiler directs the heated gases towards the chimney K and gives the
required shape to the whole structure. The double casing M is formed in panels
removable for the inspection of the partitions I, I, of tubes. A screen N of firebrick
or other like material directs the gases from the burning fuel across the rotatory
groups or bundles of tubes V, V," and a second screen which is made of iron is
employed for the same purpose and also protects the steam reservoir against the
radiation from the furnace.

page_text: My improved multitubular boiler so arranged well furmis the esseman conduitions
enumerated above as :-
1st. By the employment of tubes whose dimensions may vary according to the
requirements of each case, all the lightness possible may be obtained and by the
grouping of the tubes the volume of the whole boiler may he reduced within
the limits possible and the dimensions in length and width for the same power may
be made to vary according to circumstances.
2nd. The whole apparatus is simple and offers facilities for inspection and the
dismounting of the cylindrical groups or bundles of tubes which can be taken out of
the furnace together with their boxes; the lower reservoirs have each a part removable
to allow of the tightening and cleaning of the tubes, of the partitions and large
openings are provided to give access to the interior of the steam reservoir for the
tightening and cleaning of the tubes of the partitions at that end of such tubes; the
double casing being removable in several portions facilitates, the changing of
the tubes of the partitions for repairs and the rotary movement of the cylindrical
groups or bundles of tubes hinders the deposition of soot on such tubes.
3rd. The heating surface presented directly to the burning fuel may in consequence
of the direct radiation from the fire and in spite of the round form of the groups or
bundles of tubes, be considered as a plane surface even if it were stationary, but it is
not so with the rotary movement of the bundles or groups in which each element
successively passes the place where this radiation is the most intense, and without
exactly stating the increase of surface which may result from this movement which
experience alone will make known, it can be considered equivalent to the develop-
ment of the curved surface which the groups or bundles of tubes will present or say
fifty per cent.
4th. It is easy to understand the mechanical circulation which the rotary motion of
the groups or bundles of tubes produces. In reality the tubes occupying the position
of the upper generators of the cylindrical group are nearly empty in consequence of
their inclined position, they fill themselves progressively in their rotary movement
and are full when their upper extremities arrive at the level x, y, of the water at that
time in the groups or bundles of tubes, and the water which by its inertia is enclosed
in the tubes continues to move with them until they are at their lowest position where
the said water is subject to a maximum of pressure corresponding precisely to the
greatest intensity of radiation from the fuel in the furnace; on leaving the said
position the tubes continue their movement in the direction for the disengagement of
the steam and soon empty themselves again in allowing a free disengagement to the
steam from the water which their walls retain by capillarity.
5th. The case with which steam disengages itself from the cylindrical groups or
bundles of tubes which deliver the steam into the upper reservoir by means of the
tubes provided for the purpose has been shown, and the disengagement of the steam
from the partitions formed of tubes is not less easy since the tubes of the said
partitions open directly into the said reservoir.
It may be observed that any water which may be carried into the upper reservoir
by the steam will immediately return to its normal level in consequence of the said
upper reservoir being inclined downwards towards the back of the boiler, if such
water is not evaporated in its course by the heat which the said reservoir receives
from the gases which envelope it in their passage to the chimney and tend to ensure
the production of "dry steam."
I would have it understood that I do not confine myself to the use of the whole
boiler and the rotating cylindrical groups or bundles of tubes in the precise forms
herein before described as they will require to be modified in accordance with the
circumstances in which they are to be employed and the rotating cylindrical groups
or bundles of tubes may be placed in horizontal, vertical or inclined positions as may
be desirable in the various circumstances in which they are to be employed. Further,
the number of rotating, cylindrical groups or bundles of tubes employed in connection
with each grate or in each boiler may be adapted to the size of the boiler and to the
circumstances in which such boiler is to be employed.

page_text: Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is
1. The system of multitubular boiler hereinbefore described.
2. In steam-boilers the rotation of the cylindrical groups or bundles of tubes V for
the purpose of obtaining a mechanical circulation of the water to be evaporated, with
a view to hasten the vaporization and to facilitate the escape of the steam sub-
stantially in the manner and for the purpose herein before described in reference to
the accompanying drawing.
3. In a steam-boiler the special arrangement of the groups or bundles of
tubes V, V with boxes such as A and B and stuffing boxes or like appliances
such as E and F in combination with any driving mechanism suitable for the
purpose of imparting to the said groups or bundles of tubes a movement of rotation
substantially in the manner and for the purpose herein before described in reference to
the accompanying drawing.
4. In a steam-boiler the arrangement consisting of the partitions 1, I formed of
tubes commencing at the reservoirs L, L and terminating in the upper reservoir G, G
and enveloping the groups or bundles of tubes substantially in the manner and for the
purpose herein before described in reference to the accompanying drawing.
5. In a steam-boiler the arrangement of back and front partitions such as J, J and
lateral double walled partitions such as M, M serving to surround the cylindrical
groups or bundles of tubes V, V and the partitions I, I formed of tubes and to direct
the products of combustion from the furnace H to the chimney K, all substantially
in the manner and for the purpose hereinbefore described in reference to the drawing
hereunto annexed.
6. In a steam-boiler the combination consisting of rotating cylindrical groups or
bundles of tubes V, V, and of an upper steam reservoir G, G, connected by
tubes D, D, and C, C and pipes P and Q all arranged substantially in the manner
and for the purpose herein before described in reference to the accompanying
drawing.
7. In a steam-boiler the combination consisting of rotating cylindrical groups or
bundles of tubes V, V and partitions 1, 1 formed of tubes connected by pipes R, R
and of reservoirs L, L and of the upper reservoir G, G all arranged substantially in
the manner and for the purpose hereinbefore described in reference to the accompany-
ing drawing.
Dated this Thirteenth day of August 1890.