Improvements in Steam Generators.
Year: 1896

page_text: Date of Application, 4th Jan., 189
PROVISIONAL SPECIFICATION.
Improvements in Steam Generators.
I, RICHARD HEBER RADFORD, of 15, St. James' Row, Sheffield, in the County
of York, Mechanical Engineer, do hereby declare the nature of my said invention,
to be as follows:-
My invention though applicable to a variety of forms of steam generators,
hereinafter referred to as boilers, is more particularly applicable to boilers of the
Cornish and Lancashire type where horizontal flue tubes are employed.
The objects of my invention are to increase the heating surface and improve the
circulation in such boilers and I attain these objects in the following manner.
Boilers of the type herein referred to are usually provided with a number
of cross tubes commonly known as the Galloway water tubes, such cross tubes
being employed for similar objects to those above enumerated.
In carrying my invention into effect, instead of cross tubes, I employ coils
of pipe placed within the flue, such coils being connected with the bottom and with
the top or crown of the flue by suitable fittings or by being expanded and secured
into the plates in the manner usually employed for securing tubes in tube plates,
but by preference I should secure the coil pipe in the bottom of the flue by means
of a union or other suitable fitting which can be easily connected or disconnected
from the inside or fire side of the flue. The top of the coil pipe I should secure in
the crown plate of the flue by means of an expanding mandrill as in a tube plate
already referred to.
These pipe coils I place so that the first coil beyond the bridge of the fire grate
will leave room for a man to pass between the bridge and the coil, the pipe in the
coil is likewise so pitched that some portion of the flame would pass through the
spaces between the pipe, the coil however would only fill the upper half of the flue,
the pipe continuing along the side of the flue to the bottom connection so as to allow
of a man to pass under the body of the coil. The next coil I place in a similar
manner beyond the first coil so as to allow of a man to pass between them, this coil
however would be arranged to fill the lower half of the flue, the pipe being laid up
the side of the flue to the crown so as to allow of a man to pass over it, and so on,
every alternate coil being placed to occupy the upper part of the flue and the
intermediate coils being placed to occupy the lower part of the flue and so spaced
that a man could go under and over the successive coils from one end of the flue to
the other. The pipes in all the coils I so pitch as to allow some portion of the
flame and heated gases to pass through the spaces. This pitching of the pipe may
however be varied, as for example, those in the front coils may be closer pitched
than those in the after part of the flue, or the reverse, according to the nature of
the draught and other circumstances.
By thus arranging and spacing the coils in the flue, the flame and heated gases
which come over the bridge would impinge against the first coil, some portion of
the heated gases would pass through the spaces between the pipe in the coil
as already described, a portion however of the heated gases on meeting with the
resistance offered by the first coil would be deflected downwards to the space
underneath the first coil where it would meet with the further resistance of the
second coil, a portion would pass through the spaces between the pipe in the second
coil, and a further portion of the heated gases on meeting with the resistance
offered by the second coil would be directed upwards into the space between the

page_text: first and third coil where their passage would again follow a similar course from the
third to the fourth and succeeding coils as described from the previous coils.
As it is not convenient to make the lower coils fit close to the bottom of the flue
without leaving gaps or spaces, I provide where necessary, fire brick segments or
their equivalents, to close such spaces so that the flame and heated gases which
might follow the straighter and shorter course below the coils shall be directed
upwards to the vicinity of more effective heating surfaces than is afforded by the
bottom plates of the flue.
As a modification of the arrangement herein described in some cases I place the
whole of the coils in the upper part of the flue and I close or partially close the
lower part of the flue with baffles of fire-brick, or other refractory or non-conducting
material. By this arrangement the coils can be placed much closer together and
the pipes in the coils can be made of a wider pitch, in this way the whole of the
flame and heated gases passing over the bridge of the furnace would be brought in
contact with the surface of the tubes forming the coils or with the crown plates of
the flue.
It will be seen from the foregoing description that in either of the arrangements
the coils can be each and severally examined and cleaned and that a considerable
addition to the heating surface of existing steam boilers may be obtained, and
in many cases the necessary work to fit the coils may be effected without disturbing
the boiler from its seating.
I construct the coils herein described so that they nearly fit the flue diametrically
and in order to economise space, I make the body of the coil flat or elliptical,
in preference to circular.
In cases where it is necessary to shorten the circuit or length of pipe employed
in a coil, I sometimes bend the pipes in a zig-zag, instead of in a coil.
Dated this 3rd day of January 1896.
R. HEBER RADFORD,
Applicant.
I, RICHARD HEBER RADFORD, of 15, St. James' Row, Sheffield, in the County
of York, Mechanical Engineer, do hereby declare the nature of my said 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 though applicable to a variety of forms of steam generators,
hereinafter referred to as boilers, is more particularly applicable to boilers of the
Cornish and Lancashire type where horizontal flue tubes are employed.
The objects of my invention are to increase the heating surface and improve the
circulation in such boilers and 1 attain these objects in the following manner.
Boilers of the type herein referred to are usually provided with a number of
cross tubes commonly known as the Galloway water tubes, such cross tubes being
employed for similar objects to those above enumerated.
The objects of my invention will be better understood on reference to the
accompanying sheet of drawings in which,
Fig. 1. represents the longitudinal section of a Lancashire steam boiler.
Fig. 2. represents a cross section taken through the furnace tube on the
line À. B.
Fig. 3. represents a cross section taken through the same tube on the line C. D.
Fig. 4. represents the coils illustrated in Figs. 2 and 3, as they appear one
behind the other when looking from the end of the boiler into the furnace tube.
Fig. 5. is a plan of one of the coils.

page_text: In carrying my invention into effect, instead of cross tubes, I employ coils of
pipe,a,a, placed within the flue, b, such coils being connected with the bottom and with
the top or crown of the flue by suitable fittings or by being expanded and secured into
the plates in the manner usually employed for securing tubes in tube plates, but by
preference I should secure the coil pipe in the bottom of the flue by means of a
union or other suitable fitting, c, which can be easily connected or disconnected
from the inside or fireside of the flue. The top of the coil pipe I should secure in
the crown plate of the flue by means of an expanding mandrill as in a tube plate
already referred to.
These pipe coils I place so that the first coil beyond the bridge, d, of the fire
grate, e, will leave room for a man to pass between the bridge and the coil, the pipe
in the coil is likewise so pitched that some portion of the flame would pass through
the spaces between the pipe, the coil however, would only fill the upper half of the
Blue, the pipe continuing along the side of the flue to the bottom connection,
as shewn in Fig. 2. so as to allow of a man to pass under the body of the coil.
The next coil I place in a similar manner beyond the first coil so as to allow of a
man to pass between them, this coil however would be arranged to fill the lower
half of the flue, the pipe being laid up the side of the flue to the crown as shewn
in Fig. 3. so as to allow of a man to pass over it, and so on, every alternate coil
being placed to occupy the upper part of the flue and the intermediate coils being
placed so as to occupy the lower part of the flue and so spaced that a mau could go
under and over the successive coils from one end of the flue to the other as
is indicated by the arrows in the drawing, Fig. 1. for the purpose of cleaning
inspection or repair. The pipes in all the coils Iso pitch as to allow some portion
of the flame and heated gases to pass through the spaces. This pitching of the
pipe may however be varied, as for example, those in the front coils may be closer
pitched than those in the after part of the flue, or the reverse, according to the
nature of the draught and other circumstances.
By thus arranging and spacing the coils in the flue, the flame and heated gases
which come over the bridge would impinge against the first coil, some portion of
the heated gases would pass through the spaces between the pipe in the coil
as already described a portion however of the heated gases on meeting with the
resistance offered by the first coil would be deflected downwards to the space
underneath the first coil where it would meet with the further resistance of the
second coil, a portion would pass through the spaces between the pipe in the second
coil, and a further portion of the heated gases on meeting with the resistance
offered by the second coil would be directed upwards into the space between the
first and third coil where their passage would again follow a similar course from
the third to the fourth and succeeding coils as described for the previous coils.
As it is not convenient to make the lower coils fit close to the bottom of the flue
without leaving gaps or spaces, I provide where necessary, fire brick segments or
their equivalents, to close such spaces so that the flame and heated gases
which might follow the straighter and shorter course below the coils shall be
directed upwards to the vicinity of more effective heasing surfaces than is afforded
by the bottom plates of the flue.
As a modification of the arrangement herein described in some cases I place the
whole of the coils in the upper part of the flue the same as the first, third, fifth,
seventh and ninth coils illustrated in Fig. 1. and as shewn in the cross section of the
furnace tube Fig. 2. and I close or partially close the lower part of the flue with
removable baffles of firebrick, or other refractory or non-conducting material 9, as
shewn by the dotted lines in front of the coils Figs. 1 and 2, so that by removing
the said baffles a man may pass under the successive coils of pipe from one end of
the flue to the other for the purpose of examination, cleaning or repair. By this
arrangement the coils can be placed much closer together and the pipes in the coils
can be made of a wider pitch, in this way the whole of the flame and heated
gases passing over the bridge of the furnace would be brought in contact with the
surface of the tubes forming the coils or with the crown plates of the flue.

page_text: It will be seen from the foregoing description that in either of the arrangements
the coils can be each and severally examined and cleaned and that a considerable
addition to the heating surface of existing steam boilers may be obtained, and in
many cases the necessary work to fit the coils may be effected without disturbing
the boiler from its seating.
I construct the coils herein described so that they nearly fit the flue diametrically
and in order to economise space, I sometimes make the body of the coil flat
or elliptical, in preference to circular.
In cases where it is necessary to shorten the circuit or length of pipe employed
in a coil, I sometimes bend the pipes in a zig-zag, instead of in a coil.
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. In a Cornish or Lancashire boiler or similar type of steam generator where
horizontal flue tubes are employed, the arrangement and combination of coils
of pipe placed within the flue tubes in such a manner as to allow of a man to pass
under and over the successive coils from one end of the flue to the other in the
manner and for the purposes substantially as herein described and illustrated.
2. In a Cornish or Lancashire boiler or similar type of steam generator, where
horizontal flue tubes are employed the arrangement and combination of coils
of pipe placed within the upper part of the flue tube only. The lower part of the
flue being closed or partially closed with baffles of firebrick or other refractory
material so that by removing the said baffles a man may pass under the successive
coils of pipe from one end of the flue to the other, in the manner and for the
purposes substantially as herein described and illustrated.
Dated this 3rd day of October 1896.
R. HEBER RADFORD,
Applicant.