Apparatus for Superheating and Drying Steam.
Year: 1895

page_text: Date of Application, 7th Sept., 1895-Accepted, 12th Oct., 1895
J
[Communicated from abroad by the Firm of R. WOLF, of Magdeburg-Buckau,
in the Empire of Germany, Engineers.]
Apparatus for Superheating and Drying Steam.
I, CHARLES DENTON ABEL, of No. 28 Southampton Buildings, Chancery
Lane in the County of London, Consulting Engineer and 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 improved apparatus for superheating and drying steam,
in which a number of tubular elements are so arranged and connected in a
chamber through which the furnace gases pass, that the steam is made to pass first
through one or more of the hottest tube elements, then through one or more of
the coolest, then through the elements nearest the hottest and which are slightly
less hot, then through those nearest the coolest, and which are slightly less cool,
and so on, the steam being finally led through the middle elements of medium
beat.
The object of this arrangement is in the first place to superheat the saturated
steam in the hottest elements and to vaporise any water particles still contained
therein in the cooler tube elements, and then to superheat the steam again, and
again vaporise any water particles, and so on, until all the hot and cool tube
elements have acted alternately upon the steam, after which it is led away in a
perfectly dry and highly superheated condition.
The said superheating apparatus serves mainly for superheating and drying fresh
steam it can also be combined with a second or subsidiary superheater for utilising
the heat of the furnace gases that have passed through the main superheater for
superheating steam that has already done work, or exhaust steam.
The accompanying drawing shews the above described superheating apparatus
for fresh steam, as also the combination therewith of a subsidiary superheater for
exhaust steam.
Fig. 1 shews at the same time the combination of a main superheater by way of
example with a tubular boiler, and the combination of a subsidiary superheater
with a multiple expansion, steam engine. This figure shews the combination partly
in elevation and partly in section on line E F of Fig. 3.
Fig. 2 shews a longitudinal section on line A B Fig. 1.
Fig. 3 a section on line C D.
Figs. 4 and 5 shew the arrangement of the superheater elements and the
connections thereof with each other.
These figures also shew how the subsidiary superheater can be arranged at the
end of or between the main superheater elements.
Fig. 6 shews a single tube element of the superheater.
are
The superheater is marked H and the separate tube-elements thereof
marked m' to m; the separate connecting tubes are marked to 7. The
connections are so arranged that the superheater will operate as follows:
The moist steam coming from the boiler flows first through the first front
element m' which is exposed to the hottest furnace gases, and passes thence in a
superheated condition, but still containing a quantity of water particles, through the

page_text: In
outer tube v², and at the same velocity, into the second element me² which forms the
last element of the superheater, and is exposed to the coolest furnace gases.
the last element only a small amount of heat is transmitted from the furnace gases
to the steam flowing through, but the steam is hereby afforded the opportunity of
vaporising in great measure the water particles carried by it, without being
materially reduced in temperature thereby. From the element m² the steam
passes through the tube connection 2 into the third element m³ situated behind the
first element, whereby the steam is again subjected to the action of the hot furnace
gases, so that a farther superheating of the steam is effected.
into
From the third element m³ the steam passes through the tube connection
the fourth element which is situated inside, next the second one, and is again
exposed to the cooler furnace gases, so that here a farther drying of the steam, as
above described takes place.
This action is repeated with the following elements m³ to m³ connected respectively
by the Lubes to win alternating directions towards the centre, so that the
superheated steam is eventually led from about the middle of the superheater H to
the high pressure cylinder of a steam engine.
The number of elements forming a superheater and which are advantageously
not less than six, depends upon the extent of steam production.
The straight tube lengths of the contiguous superheater elements are so shifted
relatively to each other, that a tool can readily be passed in a slanting direction
between them for clearing the outer surfaces of soot and ashes.
As shown at Fig. 2, the combustion gases pass from the firegrate of the tubular
boiler combined with the superheater I direct from the fire tubes through a short
Hlue into the superheater, and are led thence through the flues and R to the
chimney.
Another fluer is provided which is ordinarily closed by a valve as shewn; if the
superheater is not to be used, the flue is closed by means of its valve and
the valve of fluer is opened, so that the combustion gases pass directly through r
into flue R. The said valve also serve to regulate the draught.
In this construction the steam passes from the boiler through the connecting
pipe a to the superheater H, passes through the same and is then led to the high
pressure cylinder through the connecting pipe b. After having done duty in the
cylinder, is led through the pipes cand c' to the second superheater M and
thence through the pipes d and d to the intermediate cylinder of the engine.
After doing duty herein, the steam is led through pipes f and f1 again into the
second superheater, from which it is led through pipes e and e' to the low pressure
cylinder.
In place of the construction of tubular boiler shewn, any other construction
may be employed in combination with the improved superheater.
The separate tube elements are advantageously connected together outside the
furnace chamber by means of the tubes v' to '. Hitherto these connections were
made, in very inaccessible manner, within the furnace flues.
The consequence hereof was that the making good any defective connections or
the changing of any connecting parts was very difficult and took a long time. By
arranging all these connections outside the furnace flues the said inconveniences
are avoided.
The connections of the tube elements are readily accessible from all sides, and
the simplest means can be employed for effecting the connections and packings in
the manner most suitable for high pressure steam. The direct destruction of the
parts by means of the combustion gases, which, with internally situated connections,
is very considerable, is by this means entirely avoided, and the necessary repairs
are greatly reduced.
The subsidiary superheater M situated at the end of or between the elements
of the main superheater as at Figs. 4 and 5, and which is similar in construction
to ordinary superheaters, serves for superheating steam that has already done duty
and is principally used with multiple cylinder engines, for drying or superheating

page_text: the exhaust steam from the high pressure cylinder before it passes to the inter-
nediate cylinder, and if necessary also to dry or superheat the exhaust steam
from the intermediate cylinder, before it passes to the low pressure cylinder.
The part of the subsidiary superheater situated outside the furnace flues consists
of the supply and discharge pipes c', ƒ' and d', e¹, which are connected together
in one casting.
The exhaust steam coming from the high pressure or intermediate cylinder
passes through the pipes c¹ and into the superheater M consisting of a number
of small U shaped tubes situated in the furnace flues. The dried or superheated
steam flows through to the intermediate cylinder and through e to the low
pressure cylinder.
If, with small engines it be not required to superheat the steam for the inter-
mediate cylinder, the exhaust steam can pass from the high pressure cylinder
through the pipe k, shewn in dotted lines, direct to the intermediate cylinder.
The subsidiary superheater M in that case only serves for superheating the steam
for the low pressure cylinder, and the partitions t¹ and 2 in the above mentioned
casting would then be omitted.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed declare that what I
claim is :-
1. A superheater for drying and superheating saturated steam, consisting of a
series of tube elements so combined and arranged, that the steam is caused first to
pass through one or more of the hottest tube elements, then through one or more
of the coolest, then alternately through the next hottest and next coolest tube
elements so as to issue from the last tube element situated at about the middle
part of the superheater, in a highly superheated and dried condition, substantially
as herein described.
2. A superheater of the kind referred to in the first claim, combined with a
subsidiary superheater for cooler steam, arranged at the end of the main super-
heater or between the hot and cool tube elements thereof with the object of the
better utilisation of the heat of the furnace gases and for reducing the temperature
thereof before acting upon the cooler tube elements, substantially as described.
3. In a superheater of the kind referred to in the first claim, arranging the
connections of the separate tube elements with each other outside the combustion
chamber or furnace flues, substantially as described.
Dated this 7th day of September 1895.
ABEL & IMRAY,
Agents for the Applicant.