Improvements in and relating to Steam Superheaters.
Year: 1899

page_text: Date of Application, 6th Apr., 1899
Complete Specification Left, 8th Jan., 1900-Accepted, 6th Apr., 1900
PROVISIONAL SPECIFICATION.
Improvements in and relating to Steam Superheaters.
I, THOMAS SUGDEN, of 26, Underhill Road, East Dulwich, in the County
of London, Mechanical Engineer, do hereby declare the nature of this invention
to be as follows:-
My invention relates to steam superheaters applicable to water tube, Lancashire
and other types of steam generators and is intended to improve the construction
and efficiency of such apparatus, and to facilitate cleaning and repairs when
necessary, as well as to provide for protecting the superheater when steam is
not passing through it.
The superheater consists of a number of curved tubes suspended in the path
of the furnace gases from a pair of suitable boxes or vessels through which
the steam to be superheated passes. As applied to a water tube boiler, the
aforesaid boxes or vessels are placed one on each side of the steam drum and are
supported by the drum or rest on the furnace walls, and the tubes pass under-
neath the drum and hang in the furnace space. The shape of the tubes by
preference approximates to a catenary curve. Provision is made in the boxes by
means of screw plugs, doors or lids to admit of inserting an expander for securing
the tubes in the boxes. I may leave a space between the boxes and the sides of
the steam drum to allow of the withdrawal and insertion of tubes as may be
required through such space, or the tubes may be inserted and withdrawn through
the openings in the boxes. By this provision a damaged or faulty tube can be
very readily replaced without disturbing the superheater as a whole. The steam
on leaving the boiler enters one of the boxes aforesaid, and then passes through
the tubes of the superheater into the other box, and thence to the steam pipe.
Stop valves are provided to allow of shutting off the superheater from the boiler
and from the steam main.
In order to protect the superheater tubes when desirable from the direct
impingement of the furnace gases upon them I provide at the front end thereof
a suitable balanced damper or shield which is made to be raised and lowered,
or to be-turned about an axis, so that in either case it can be adjusted in front
of the tubes or can be moved away to expose the tubes to the direct impingement
of the furnace gases. This shield is intended to be adjusted in front of the tubes
when steam is getting up, or when the boiler is "standing." Shields may also be
provided to protect the tubes underneath. To further protect the tubes during the
time when getting up steam, or when the boiler is shut off from the steam main,
I provide for passing air through the superheater to keep the parts cool and so
prevent damage from overheating. To do this I close the steam valves, thereby
isolating the superheater, and then open other valves provided at the ends of
the superheater boxes, or I remove suitable caps or lids from said boxes to allow
air to circulate through the tubes, and if necessary I may force or draw the air
through the superheater by a fan or the like, or I may utilize the draught of
the chimney for drawing air through the superheater. For this purpose a con-

page_text: nection may be made from the superheater to the chimney either direct or through
the ash pit or furnace. In the latter case the connection may be by a pipe, or
by a channel in the furnace wall, and the heat taken up by the air is utilized
for the purposes of combustion. In cases where air is not passed through the
superheater, a single stop valve only is required.
Another method of keeping the tubes cool when stopping or shutting off a
boiler for example is by admitting air into the furnace space through the cleaning
doors which are arranged near to the superheater boxes.
When applying my improved superheater to a Lancashire, Cornish, or marine
boiler I prefer to place it in the down take at the back end of the boiler, so
arranging the tubes that they do not interfere with the examination and cleaning
of the internal tubes and flues of the boiler.
The chief advantages of my superheater are as follow: All the tubes are
duplicates, and can be readily removed and replaced without disturbing the
superheater. No joints are exposed in the path of the heated gases. The tubes
are very advantageously situated for intercepting the heat, and protection is
afforded the tubes when the boiler is getting up steam or "standing," by dampers
or shields and by the provision for passing air through the tubes so as to prevent
them from being damaged by excessive heat. Moreover the tubes are readily
accessible for cleaning externally by means of a steam jet introduced through
openings at the sides of the furnace, and further a damaged tube may be plugged
or stopped through the openings in the boxes without having to enter the
heated flues.
Dated this with day of
لسعد
1800
GEORGE HARRISON,
35, Therapia Road, Honor Oak, London,
Agent for the Applicant.
Improvements in and relating to Steam Superheaters.
THOMAS SUGDEN, of Brooklyn, 26, Underhill Road, East Dulwich, in the County
of London, Mechanical 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 steam superheaters applicable to water tube, Lancashire
and other types of steam generators and is intended to improve the construction
and efficiency of such apparatus, and to facilitate cleaning and repairs when
necessary as well as to provide for protecting the superheater from the flame and
furnace gas when steam is not passing through it.
My improved superheater comprises a number of curved tubes suspended in the
path of the furnace gases from a pair of suitable boxes, vessels or pipes through
which the steam to be superheated passes on its way to the steam main. As
applied to a water tube boiler the aforesaid boxes, vessels or pipes, hereinafter
comprehensively referred to as boxes, are placed one on each side of the steam
drum or drums and are supported thereby or rest on the furnace walls, and the
tubes pass underneath the drum or drums and hang in the furnace space.
When applying my improved superheater to a Lancashire, Cornish or marine
boiler, I prefer to place it in the down-take at the back end of the boiler, so
arranging the tubes that they do not interfere with the examination and cleaning
of the internal tubes and flues of the boiler.

page_text: The steam on leaving the boiler enters one of the boxes aforesaid and then
passes through the tubes of the superheater into the other box and thence to the
steam pipe or main. Stop valves are provided to admit of shutting off the super-
heater from the boiler and from the steam main.
Provision is made for the ready withdrawal and insertion of one or more
superheater tubes as may be required without disturbing the superheater as a
whole, and an adjustable shield or shields is or are provided for protecting the
tubes from the direct impingement of the furnace gases upon them, when
desirable. Provision is also made for passing air through the tubes to further
protect the same when raising steam or when the boiler is standing
under fire," and such heated air may be advantageously utilised in the furnace
for the purposes of combustion.
66
In the accompanying drawings, I have shown how my invention may be con-
veniently and advantageously applied to a water tube boiler, by way of example.
A boiler having two steam drums is shown, but the mode of application is the
same for a boiler having a single steam drum.
Figure 1 is a side elevation of the superheater and of so much of the boiler
with the side furnace wall removed as is necessary to show how the superheater
is applied thereto.
Figure 2 is a plan of the same, one of the side boxes being shown partly in
section, and
.
Figure 3 is a transverse section taken on the line a, a of Figure 2 looking
toward the right of said figure. Like letters of reference denote corresponding
parts in the several figures.
A, A are the curved tubes of the superheater, suspended in the path of the
furnace gases from a pair of hoxes B, B which are placed parallel to, and one on
each of, the steam drums C, C, and which may be conveniently supported from
the sides of the steam drums by brackets such as D, Figure 3. The shape of the
tubes A approximates by preference to a catenary curve so that the tubes are
independent of temperature and do not become distorted by their weight when
heated. The tops of the boxes 13 are formed with a number of elongated openings
which are closed by lids or covers b. This construction allows of the insertion
of an expander for securing the tubes in the boxes. In lieu of the elongated
openings and covers b, circular openings closed by screw plugs may be used.
I leave sufficient space between, the boxes B, and the sides of the drums C to
admit of the withdrawal of the tubes through such space after the same have
been released from the boxes, or the tubes may be inserted and withdrawn through
the openings in the tops of the boxes. By such provision, a damaged or faulty
tube can be very readily replaced without disturbing the superheater as a whole.
This space between the boxes and the steam drums is closed by plates M which if
desired may be hinged. The space between the boxes and the furnace walls is
closed by blocks N.
The steam on leaving the boiler enters one of the boxes 1 through the pipe E
and then passes through the tubes A into the other box B and thence to the steam
main F. Besides the usual stop valve G on the steam drums, I provide other stop
valves H1, H2, and H, for a purpose that will hereinafter appear.
In order to protect the superheater tubes when desirable from the direct
impingenient of the flame and furnace gases upon them I provide at the front
end thereof a shield or damper J extending across the furnace space. The said
shield is shown working in grooves in the side walls of the furnace and sup-
ported by chains J and balance weights by which it can be readily raised and
lowered as required. When the shield is lowered, the furnace gases are directed
toward the superheater tubes, and when it is raised the tubes are protected and
the gases pass under them. The shield is intended to be adjusted in front of the
tubes when steam is being raised or when the boiler is "standing under fire."
In lieu of a sliding shield, a pivoted shield may be used, and, if desired, a shield
or shields may also be provided to protect the tubes underneath.

page_text: ...To further protect the tubes during the time when steam is being raised
.or when the boiler is shut off from the steam main 1 provide means for passing
air through the superheater to assist in keeping the tubes cool and so prevent
damage from overheating. For this purpose I have shown a pipe connection K
joined, at the end of one of the boxes B and having an elongated opening at the
side communicating with a channel L in the furnace wall which channel opens
into the ash pit or furnace. By closing the stop valves G. and H³, and opening
the stop valves H and H2, which are closed when the superheater is at work, a
current of air is drawn through the superheater, tubes by the draught, of the
chimney, and excessive heating of the tubes is prevented. The air thus, heated
by its passage through the tubes is advantageously used for promoting combustion
in the furnace. In some instances the valve H2 may be dispensed with and one
or more of the lids or covers 6 may then be removed to admit air into the super-
heater when required. If necessary or desirable the air may be drawn or forced
through the superheater by a fan or the like.
This can
Sometimes I assist in keeping the tubes cool when stopping" or "shutting
off" a boiler for example, by admitting air into the furnace space.
be done by raising the plates M. .
The chief advantages of my superheater are as follows:-No joints are exposed
in the path of the heated furnace gases. The tubes are uniform in length and
shape. One or more of them can be readily removed and replaced without
disturbing the superheater as a whole. Moreover they are very advantageously
situated for intercepting the heat, and protection is afforded them, when steam
is being raised or when the boiler is "standing under fire," by means of dampers
or shields and by the provision for passing air through them so as to prevent
damage thereto by excessive heat. The tubes are moreover readily accessible for
cleaning externally by means of a steam jet introduced through the openings
at the sides of the boxas when the plates AL are raised; and, further, a damaged
or faulty tube may be plugged or stopped through the openings in the boxes
by removing the covers and without having to enter the heated furnace chamber
or flues.
The construction is similar for a Lancashire or Cornish boiler, but in such a
case the superheater is placed at the back end of the boiler and the tubes hang
in the down-take being so arranged as not to interfere with cleaning and examina-
tion of the flues and internal tubes.
Having now particularly described and 'ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is: :-
"
1. A steam superheater comprising a pair of side boxes placed between the
main stop valve on the boiler and the steam main, and a number of curved tubes
of uniform length hanging from said boxes in the path of the furnace gases,
the shape of the tubes approximating to a catenary curve, substantially as
described.
2. The construction of a steam superheater with side boxes in which the tubes
are expanded, said boxes being arranged so as not to be exposed to the flame and
in a position accessible for expanding the joints and for taking out, replacing
and plugging the tubes, as may be required, substantially as described.
3. The combination with the steam drum or drums of a water tube boiler, of
the superheater herein described so constructed and arranged that the superheater
tubes can be passed into position and withdrawn through the space between the
drum or drums and the side boxes of the superheater, substantially as described.
4. The combination, with the superheater hereinbefore described, of an adjust-
able shield or shields for protecting the superheater tubes, when required, from
the direct impingement of the flame and furnace gases upon them, substantially
as described.
5. The combination with the superheater, of a sliding damper or shield

page_text: arranged at the front end of the superheater, substantially as described and
illustrated in the accompanying drawings, and for the purposes specified.
6. The method of preventing excessive heating of the superheater tubes, when
steam is being raised or when the boiler is standing under fire," by passing air
through the said tubes, substantially as described.
7. The method of utilizing the natural draught of the chimney for drawing air
through the superheater tubes, substantially as described.
8. The manner of utilizing the heated air for the purposes of combustion after
the same has passed through the superheater tubes, by conducting it into the
ash pit or furnace, substantially as described.
9. The method of cooling the superheater tubes by admitting air to the furnace
space through the cleaning doorways or other openings, substantially as described.
10. A steam superheater constructed substantially as described with reference
to the accompanying drawings.
Dated this 6th day of January 1900.
GEORGE
HARRISON,
11 & 12, Southampton Buildings, London, W.C.
Agent for the Applicant.