Year: 1887

page_text: Date of Application, 7th Sept., 1887
Complete Left, 7th June, 1888
Complete Accepted, 13th July, 1888
BENJAMIN HOWARTH THWAITE of 37 Victoria Street Liverpool in the County of
Lancaster Civil Engineer do hereby declare the nature of this invention to be as
follows:-
My Invention relates to improvements in Tubulous Steam Generators, by which I
obtain a great evaporative surface efficiency with a minimum degree of priming action
a safe and durable construction and a method of jointing the tubes by which they can
be quickly removed renewed or repaired.
The general principle of steam generator to which my Invention is more particularly
applicable, is that invented by Jean Marie Felix du Temple, consisting of very small
generating tubes arranged so that the mixture of steam and water cannot rise so fast
as to disturb the action of the boiler, as is the case invariably when the tubes are too
large, as on opening the steam valve the water makes its way to this opening as speedily
as possible and soon empties the boiler.
Referring to sheet of drawings which is intended to accompany and form part of
this specification,
Figure 1 is a cross section, shewing the general arrangement of my Invention,
Figure 2 is a part longitudinal section and Figure 3, a detail of method of jointing the
tubes.
I will enumerate the improvements categorically as follows-
First I provide a steam drum A of oval form with a number of tubes B traversing
it, serving as stays, and distributing the products of combustion equally-increasing
at the same time the heating surface, and drying the steam, in order to act as a
separator these tubes pass through a plate (, situated slightly higher than the water
level the holes in the plate are about 2 millimetres larger than the tubes, this plate also
serves as a stay for the drum ends.
Second. I form a jacket D on each side of the length of the drum into which each
set of generating tubes E empties its contents of steam or water (instead of allowing
the steam to bubble up through the body of the water, taking up with it part of the
latter) and carries it up to the upper part of the jacket where the mixture finds a
1...כנ
931

page_text: number of small outlets F F F., the water by reason of its greater momentum is
projected with some force against the surface of the water in drum-and adheres
thereto, the steam finding its way to the central perforated collecting pipe.
Third, Consists in improvements in the joints of the generating tubes, to receive
these and to strengthen the drum A, a strip C is rivetted on the whole length
occupied by the tubes, the bolts H are no longer studs but are inverted in T grooves,
so that when the tubes are taken out, the bolts can be removed, and in case of breakage
easily replaced, the mode of making the bolts and the clamps is clearly shewn on
drawing.
I may arrange two drums connected with horizontal tubes and I may use longi-
tudinal baffler plates of iron or of refractory material so as to compel the products of
combustion and flame to traverse and retraverse over the generator tubes, opposite the
edges of the baffler plates, in the sides of combustion chamber I provide movable pieces
by which I can withdraw baffler plates.
The boiler shewn in figures, and intended to illustrate my invention, has 96 square
feet of heating surface per foot in length, counting from K see figure 2.
The square foot of heating surface gives about 21 lbs. of steam per hour, or about
2000 lbs. per hour per foot run.
I may lead the waste products of combustion from steam generator through a
vertical nest of recuperator tubes past, the outside of which I may lead the air or the air
and steam to support gaseous or solid fuel combustion in boiler furnace or the air may
pass through the tubes and the waste products of combustion outside them.
Dated this 6th day of Santamba 1007

page_text: I, BENJAMIN HOWARTH THWAITE of 37 Victoria Street Liverpool Civil Engineer
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:
My Invention relates to improvements in Tubulous Steam Generators by which I
obtain a great surface evaporative efficiency with a minimum degree of priming action,
a durable and safe construction and an improved method of jointing.
Before referring to the six sheets of drawings that accompany and are intended to
form part of this invention I wish it to be understood that I do not intend to be con-
fined to the exact details shewn therein, as they may be modified without departing
from the nature of my said Invention.
Referring to Sheet 1 of drawings, figure 1 is a cross section and figure 2 is a
longitudinal section shewing one arrangement of my invention.
I provide a steam drum A either of oval or circular sectional form, provided with a
number of tubes B. traversing it, which serve as stays and distribute the products of
combustion equally, increasing at the same time the heating surface and drying the
steam, these tubes pass through a separator plate C situated slightly higher than the
water level, the holes in the separator plate are about 2 millimetres larger than
the tubes, this plate also serves as a stay for the drum ends.
1 form a jacket D on each side, and of the length of the steam drum, into which
each set of generating tubes E empties its contents of steam or water, instead of
allowing the steam to bubble up through the body of the water. In my invention,
the mixture of steam and water ascends to the upper part of the jacket, where the
mixture finds a number of small outlets F F F, or a longitudinal knife edge opening FA.
The water by reason of its greater momentum is projected with some force against the
surface of the water in the drum and adheres thereto, the steam finding its way to the
central perforated outlet collecting pipe A¹ into which it enters in a dry condition
and suitable for a steam motor-Immediately under the knife edge opening FA
I may place a knife edge plate to catch any suspended water remaining in the
steam.
In order to strengthen the steam drum A and prepare it for the reception of the
generator tubes E a strip G is rivetted on to the side of steam drum the entire length
occupied by the tubes.
The bolts H. are no longer studs-but are inserted in T grooves, so that when the
tubes require to be taken out, the bolts can easily be removed as well as the tubes and
in case of breakage can be quickly replaced, the mode of making the T bolts and the
clamps is clearly shewn in figures 34 and 5 on sheet 2 of drawings representing full
size details of method of tube attachment,

page_text: Figures 6 and 7 shew respectively a cross-section and longitudinal section of another
modification of my Invention of which figures 89 and 10 on sheet 4 are details of the
methods of attachment.
Instead of making the generator tubes E in one length as shewn in figure 1, I use
short shaped segmental generator tubes I. which are inserted in vertical cast steel
collectors J or K: each of these collectors J J or K K, carries two vertical rows of
such tubes, the latter are simply rolled into their sockets by the Dudgeon, or other
tube Expander which may be inserted for this purpose by simply removing the scrow
plug L.
The vertical collector chainbers J¹ and K' (of collectors J and K,) are of two
patterns one large ono J¹, and the other short K¹.
The chambers JJ' have cross partitions, forming chambers-connecting the ends of
the two tubes following in the vertical plane. The end chambers (top and bottom)
only receive one end each, of each of the three initial rows of U tubes.
The collectors J J-K K are in connexion with the horizontal collecting pipe M.
and are provided with spherical joints N.
The collectors J J, K K are held against the collecting pipe M. by bolts and
clamps O and O', and at the upper ends the collectors are attached to steam drum by
the tubes P.
It will be observed that the U shaped tubes, are not all in the same horizontal plane,
but are at two alternate levels.
The arrangement of my Invention allows of any of the sections to be taken out at
the smoke doors.
At the back or opposite the collectors, there are plates Q forming the sides, and
which plates can easily be removed when the collector and tubes have to be taken
out. By this modification less space is required for fixing the steam generator
because all the tubes can be removed from one side, a great advantage in marine
applications Local repairs can also be quickly and economically effected.
The water descends at the two ends of the steam drum by the pipes R into
collecting pipes M.
The steam and water in generator tubes escape into a steam separator cavity S.
in steam drum A, by which the inflow of the mixture of steam and water is pro-
vented from causing priming. The steam escapes under the edges of separator
plate T. and ascends into steam space of drum, comparatively free from suspended
water.
I may provide an air space U, around side casing of steam generator, through
which I force the air when I employ forced draught, by this means I recover the
heat otherwise lost by radiation from sides of steam generator.
Figures 11 and 12 sheet 5 of drawings shew a cross and longitudinal section of
another modification of my Invention in this arrangement I employ the steam
drums V and W, provided with a separator cavity plate X, by which the mixture
of steam and water issuing from the generator tubes is checked in velocity, and
separated, issuing around-and from under the sides of separator plate.
In this arrangement the products of combustion, flow through the space provided
between the two steam drums, the flow of combustion gases, through the nest of
generator tubes being checked and equalised by the baffle plate, Y. which is perforated
with holes Z.
The products of combustion flow between and over the steam drums V and W around
a nest of air recuperator tubes 4. The products of combustion flow around these tubes
and transmit their remaining heat thereto. The air blown or forced descensionally
through the tubes by any well known manner becomes heated in its passage and
adds to the heat of combustion either of solid fuel or in the arrangement shewn of
gaseous fuel, the latter enters into a gas distributing chamber 5 where it meets the
air flowing into an annular flue 6.
Figures 13 14 and 15 sheet 6 of drawings show a modified arrangement of firegrate
adapted to my steam generator when using my Invention along with the Donelley

page_text: Referring to Figures 13 14 and 15. which shew respectively a cross section front
elevation and plan—
Vertical generator tubes 8. form the back of fuel on fire the tubes are connected at
the upper end to steam drum 9; and at the lower end to collecting water pipe 10,
which is connected at each end by junction pipes 11 to descensional depositing water
pipes 12.
The firegrate may be fed with heated air either by natural or forced draft-the air
being drawn or forced through air recuperator chambers F as shewn in figures 11
and 12.
By the use of my Invention I obtain a great evaporative surface efficiency, with a
minimum degree of priming-The maximum calorific efficiency of the fuel, and a safe
and durable form of construction for the highest useful steam pressures--and a method
of tube jointing by which repairs can be quickly and easily effected.
Having now particularly described and ascertained the nature of my said Inven-
tion and in what manner the same may be performed I declare that what I claim
is as follows-
1st. The arrangement for effecting the separation of steam from the water in a
steam generator of the tubulous type substantially as herein shewn and described.
2nd. The arrangement for jointing the generator tubes to steam drum and collecting
pipe, substantially as shown in figures 3 4 and 5.
3rd. The arrangement of U shaped generator tubes and collecting chambers, and
method of jointing same substantially as shown in figures 6 to 10.
4th. The arrangements of the elements to form a tubulous steam generator consisting
of two steam drums, generator tubes and two water collecting tubes as shewn in
figures-11 and 12.
5th. The air heating or recuperative arrangement in combination with a tubulous
steam generator substantially as herein shewn and described in figures 11 and 12.
6th. The arrangement of generator tubes with water collecting and vertical circula-
tion pipes in combination with a solid fuel fire of the Donally or similar grate
substantially as shewn in figures-13 14 and 15.
Dated this 6th day of June 1888