Improvements in Apparatus for Superheating Steam.
Year: 1897

page_text: Date of Application, 19th Jan., 1897
Complete Inorification Loft 10th Nov 1907 Accented
10th Enh
4000
Date of Application, 19th Jan., 1897
Complete Specification Loft, 19th Nov.
1007
Accepted, 10th Feb., 1908
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Superheating Steam.
We, SAMUEL CHATWOOD, of 76, Newgate Street, in the City of London, Bankers'
Engineer, and SAMUEL RAWSTHRONE CHATWOOD, of the Lancashire Safe and Lock
Works, Bolton, in the County of Lancaster, Bankers' Engineer, do hereby declare the
nature of this invention to be as follows:-
.
We employ for this purpose a furnace with a fire box at the lower part communi-
cating preferably horizontally with a firebrick chamber which becoming highly
heated promotes perfectly combustion and prevents fluctuation of temperature.
From this chamber another chamber preferably situate above the first and above the
fire box is entered and this chamber again communicates at the front end by a rising
passage with another preferably horizontal return chamber which passes from front
to back and at the back by a descending flue is connected with a chimney. In these
chambers pipes are laid through which the steam to be superheated is passed. The
steam pipes traverse the two chambers lengthwise, they enter the upper chamber at
the cooler end and passing to the other end descend and then traverse the lower
chamber from front to back.
In order to superheat say 1000 lbs. of steam per hour we should employ say twelve
parallel tubes of inch bore and each exposing a length of forty feet.
The pipes which lie in the lower pipe heating chamber which are more highly
heated than those in the upper chamber are protected from the direct impact of the
flame and heated gases by being laid at the lower part of the chamber under shelter
of a protecting wall or bridge; these portions of the pipes are heated principally by
radiation from the hot brickwork forming the roof of the chamber. This precaution
is taken to prevent rapid wear of the pipes arising not only from the high temperature
but also from the oxygen of the air mingled with the gases being as yet only
imperfectly consumed. The pipes in the upper heating chamber where the tempera-
ture is lower and the gases more perfectly consumed are fully exposed to the draught
through the chamber. The shell or outer wall of the furnace is of brickwork and
in the brickwork air passages are sometimes arranged by which air passes to the
ashpit of the furnace. The air current which can be regulated by dampers serves
both to preserve the brickwork and to heat the air provided for the combustion of
the fuel. The superheated steam is delivered into a storage chamber or into passages
of large capacity which lead the steam to the engine for we find it essential to
economical working that the steam should have a high velocity whilst passing through
the superheating pipes and a low velocity in traversing the receiving chamber.
Where the engine is compound we provide two sets of superheating pipes in the
furnace each with its storage chamber and by the one set we superbeat the steam
before it enters the high pressure cylinder and by the other set we again superheat
the steam in' its passage from the high pressure cylinder to the low pressure cylinder.
When two sets of superheating pipes are thus provided they may or may not be
separated the one from the other by partitions in the heating-chambers and if so
separated dampers should be provided to direct the draught so that the heat may
be separately regulated to the two sets of pipes.

page_text: Similarly in the case of triple and quadruple expansion, three and four sets of
superheating pipes and storage chambers may be provided.
Dated this 19th day of January 1897.
SAMUEL CHATWOOD.
S. R. CHATWOOD.
By Carpmael & Co.,
Agents for the Applicants.
.
.
Improvements in Apparatus for Superheating Steam.
We, SAMUEL CHATWOOD, of 76, Newgate Street, in the City of London, Bankers'
Engineer, and SAMUEL RAWSTHRONE CHATWOOD, of the Lancashire Safe and Lock
Works, Bolton, in the County of Lancaster, Bankers' 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
We employ for this purpose a furnace with a fire box at the lower part communicating
preferably horizontally with a firebrick chamber which becoming highly heated
promotes perfect combustion and prevents fluctuation of temperature.
a
From this chamber another chamber preferably situate above the first and above
the fire box is entered and this chamber again communicates at the front end by
rising passage with another preferably horizontal return chamber which passes from
front to back and at the back by a descending flue is connected with a chimney. In
these chambers pipes are laid through which the steam to be superheated is
passed. The steam pipes traverse the two chambers lengthwise, they enter the
upper chamber at the cooler end and passing to the other end descend and then
traverse the lower chamber from front to back.
In order to superheat say 1000 lbs. of steam per hour we may employ say twelve
parallel tubes of inch bore and each exposing a length of forty feet.
We now however prefer to employ fewer pipes of larger diameter and containing
within them spirally bent metallic bars. This modification is the subject of the
Patent No. 2650 in the present year.
The pipes which lie in the lower pipe heating chamber which are more highly
.heated than those in the upper chamber are protected from the direct impact of
the flame and heated gases by being laid at the lower part of the chamber under
shelter of a protecting wall or bridge; these portions of the pipes are heated
principally by radiation from the hot brickwork forming the roof of the chamber.
This precaution is taken to prevent rapid wear of the pipes arising not only from the
high temperature but also from the oxygen of the air mingled with the gases
being as yet only imperfectly consumed. The pipes in the upper heating chamber
where the temperature is lower and the gases more perfectly consumed are fully
exposed to the draught through the chamber. The shell or outer wall of the
furnace is of brickwork and in the brickwork air passages are sometimes arranged
by which air passes to the ashpit of the furnace. The air current which can be
regulated by dampers serves both to preserve the brickwork and to heat the air
provided for the combustion of the fuel. The superheated steam is delivered into
a storage chamber or into passages of large capacity which lead the steam to the
engine for we find it essential to economical working that the steam should have a
high velocity whilst passing through the superheating pipes and a low velocity in
traversing the receiving chamber.

page_text: Where the engine is compound we provide two sets of superheating pipes in the
furnace each with its storage chamber and by the one set we superheat the steam
before it enters the high pressure cylinder and by the other set we again superheat
the steam in its passage from the high pressure cylinder to the low pressure
cylinder. When two sets of superheating pipes are thus provided they may or may
not be separated the one from the other by partitions in the heating chambers
and if so separated dampers should be provided to direct the draught so that the
heat may be separately regulated to the two sets of pipes.
Similarly in the case of triple and quadruple expansion, three and four sets of
superheating pipes and storage chambers may be provided.
In the annexed drawings Figure 1 is a longitudinal and vertical section of a
superheater in accordance with our invention, Figure 2 is a transverse section, and
Figure 3 is a horizontal section in various planes.
In this superheater the pipes are arranged horizontally.
Figures 4 and 5 are vertical sections of an upright superheater in accordance with
our invention.
Figures 6 and 7 are horizontal sections of the same.
Figure 8 is a transverse vertical section of a double superheater having the same
general arrangement as in Figures 1, 2 and 3.
Figure 9 shows a longitudinal section of one of the heating pipes with a spirally
bent bar within it. Figure 10 shows a transverse section of the same.
Figures 11 and 12 show another form in which a spirally bent bar of smaller
dimensions is employed.
Figures 13 and 14 are transverse sections showing other forms which may be given
to the spirally bent bar.
In Figures 1, 2 and 3, D is the fire box, E is a combustion chamber, F is a
chamber in which the tubes are heated mainly by radiation from the roof and walls.
They are protected from the direct action of the flame by the bridge f. G is a
chamber in which the tubes are heated by direct contact of the gases.
H is a
flue to the chimney. I and J are dampers. The damper I controls the draught
through the apparatus when working, the damper J is intended to be opened
during stoppages in order to pass the flame and heated gases to the chimney without
their coming into contact with the tubes. K is an air inlet through which the air
for combustion enters the apparatus, it then finds its way through the cavities L to
the ashpit M. A is the header at which the steam is admitted and by which it is
distributed to the tubes. It passes through one range of tubes to the header B' which
communicates with the header B, and from the header B2 through another range of
tubes to the header C from which it passes to the engine.
The arrows show the direction of the steam in passing through the apparatus.
The arrows → show the direction in which the air required for combustion
passes through the apparatus.
The arrows
through.
→show the direction in which the flame and furnace gases pass
A portion of one of the pipes in Figure 1 is broken away to show the spirally
bent bar lying within it or as before mentioned in place of employing these spirally
bent bars inore numerous pipes of smaller diameter may be provided.
In Figures 4, 5, 6 and 7 the combustion chamber E and the radiating chamber F
are combined and marked E F. The letters and arrows marked upon it have the
same significance as in Figures 1, 2 and 3.
Figure 8 is a section of a superheater similar to that shown in Figures 1, 2 and 3
but divided by a partition N so as to superheat the steam for a compound engine
before admission to the high-pressure cylinder and again before admission to the
low-pressure cylinder.
In the Figures 9 to 14, 00 represents the heating pipe, it is shown full size or
thereabout, and P is the spirally bent bar contained within the pipe.
Having now particularly described and ascertained the nature of our said

page_text: invention and in what manner the same is to be performed we declare that
what we claim is :-
1. A superheater such as is shown by Figures 1, 2 and 3 in which there are three
superposed fire brick chambers E, F and G arranged one over the other and which
the products of combustion from a fire box D traverse in succession; and in which
upper chambers F and G superheating pipes are laid horizontally in such manner that
the pipes in the lower chamber Fare somewhat protected from contact with the flame
whilst those in the upper chamber G are as directly as possible exposed to it; the
connections also of the superheating pipes being such that the steam enters at the
cooler ends of the pipes which are laid in the upper chamber and passes away to
the engine or otherwise from the hotter end of the lower chamber F.
2. A superheater such as is shown by Figures 4 to 7 in which there are two
vertical heating chambers E.F and G traversed by products of combustion from a fire
box D which ascend through the chamber E F and descend by the chamber G, and
escape at the lower end to a chimney; such chambers being traversed by vertical
heating pipes which steam enters near the lower or cooler end of the chamber G,
it ascends these pipes descends those in the chamber E F and passes to the engine
or elsewhere from the lower ends of the pipes which are near the hotter end of the
hotter chamber E F.
3. A double or multiple superheater such as is represented by Figures 1, 2 and 3
but provided with a partition or partitions N in such manner as admits of two or more
superheating operations being simultaneously conducted therein.
4. Superheaters substantially as described and shown by the annexed drawings.
Dated this 10th day of November 1037.
SAM. R. CHATWOOD.
SAMUEL CHATWOOD.
By Carpmael & Co.,
Agents for the Applicants.
SAM. R. CHATWOOD.
SAMUEL CHATWOOD.
By Carpmael & Co.,
Agents for the Applicants.