Improvements relating to Steam Generators.
Year: 1895

page_text: Improvements relating to Steam Generators.
I, HUGH MCPHAIL, of The Towers Wakefield, in the County of York,
Engineer, do hereby declare the nature of this invention to be as follows :-
-:
This invention relates to the production of dry and superheated steam and
consists in further improvements on the invention described in the Specification of
prior Letters Patent No. 11044* of 1892.
In the Specification of the aforesaid Patent the pipes in the generator through
which the steam passes after leaving the superheating apparatus are with the
exception of the short length leading to the stop valve wholly below the water
level and the transference of heat that takes place is chiefly between the steam in
the pipes and the water in the boiler.
According to the present invention, the pipes, tubes, chambers or coils through
which the steam from the superheaters passes before arriving at the stop valve are
located wholly within the steam space of the boiler or partially in the steam space
and partially in the water space. In this case the transference of beat is wholly
between the steam in the said pipes, tubes, chambers or coils, and the steam in the
steam space of the boiler, or partially between the steam in the pipes, tubes,
chambers or coils and the steam in the steam space of the boiler and partially
between the steam in the pipes tubes chambers or coils and the water in the water
space of the boiler. The pipes, tubes, chambers, or coils may be varied as may be
thought necessary or desirable.
This apparatus or arrangement is used in conjunction with superheaters
constructed of boxes and pipes or tubes arranged to suit the various types of
steam generators, and the circumstances and conditions surrounding them, and
their purposes, and with a sufficient number of pipes or tubes having at least a
combined internal area capable of passing the whole of the steam generated in
the boiler. The shape of the boxes and tubes, and the bends of the tubes may be
varied to suit different requirements and different classes of boilers and the method
of attaching the boxes and tubes together; and the method of attaching the
boxes or tubes to the generator may be varied as may be thought necessary or
desirable.

page_text: Improvements relating to Steam Generators.
1, HUGH MCPHAIL, of The Towers, Wakefield, in the County of York,
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:-
This invention relates to a method of and means for producing dry and
superheated steam and comprises further improvements on the invention described
in the Specification of prior Letters Patent No. 11044 of 1892.
According to the said prior invention the pipes in the generator through which
the steam passes after leaving the superheating apparatus are with the exception of
the short length leading to the stop valve wholly below the water level, and the
transference of heat that takes place is chiefly between the steam in the pipes and
the water in the boiler.
According to the present invention the superheated steam before arriving at the
stop valve is passed through a series of pipes, tubes, chambers or coils which are
located wholly or substantially wholly within the steam space of the boiler so that
the transference of heat is between the steam in the said pipes, tubes, chambers or
coils, and that in the steam space of the boiler. The pipes, tubes, chambers, or
coils may be varied in construction and arrangement as may be thought necessary
or desirable.
This apparatus is used in conjunction with superheaters constructed of boxes and
pipes or tubes arranged to suit the various types of steam generators, and the
circumstances and conditions surrounding their use, the said superheaters being
constructed with a sufficient number of pipes or tubes having, at least, a combined
internal cross-sectional area capable of giving passage to the whole of the steam
generated in the boiler. The shape of the boxes and tubes, and the bends of the
tubes may be varied to suit different requirements and different classes of boilers
and the method of attaching the boxes and tubes together; moreover the method
of attaching the boxes or tubes to the geuerator may be varied as may be thought
necessary or desirable.
Referring to the accompanying drawings which illustrate my invention.
Figure is a sectional elevation of a Lancashire boiler having my invention
applied thereto.
Figure 2 is a similar view showing a slightly modified form of my invention.
Figures 3 and 4 are vertical central longitudinal sections of portions of the rear
ends of two boilers showing further modified forms of my invention.
Figure 5 is a side elevation of a portion of the rear end of a boiler showing a
further modified form of my invention.
Figure 6 is a sectional elevation of a water tube boiler having my invention
applied thereto, and
Figure 7 is a vertical central longitudinal section of a marine boiler to which my
invention is applied.
can
Like letters of reference denote corresponding parts in the several figures.
A is the boiler shell; R is a superbeater which may assume various shapes, for
example, it may conveniently consist of two boxes b, Figure 1 connected by a
large number of small bent tubes 3, 62 so that the steam entering the box
traverse the tubes 62, 62 and so pass to the other box 6'. In lieu of two boxes such
as b, may employ one box divided into two compartments by means of a
partition 63 as shown in Figures 2, 3 and 5 the small tubes 63 in such cases forming
the communication from one compartment or box to the other. In Figure 4 I have
shown a superheater formed of a top box band a bottom box &* connected by bent

page_text: tubes & through which the steam passes from the box to the box b'. Another
precisely similar arrangement of boxes and tubes is provided and placed alongside
those just described, the bottom box being connected to the box by a pipe b and
the top box being connected to the pipe E which is shown broken to avoid
confusion. The steam passes upwards, through this second superheater and thence
by the pipe E into the boiler or generator. It is obvious that in lieu of the
separate boxes situated at top and bottom of these superheaters one top box and
one bottom box with partitions may be used.
Figure shows a slightly modified form of superheater the tubes 62 of which
have a large bend at the bottom. The steam passes out by the pipe D' through
the back end plate of the boiler to one compartment of the box of the superheater
and thence traverses the pipes 62 and enters the other compartment of the super-
heater box, and thence it passes through the pipe E to the stop valve.
pipe E enters the boiler through the crown of the shell as shown.
The
The superheaters shown in Figures 6 and 7 are similar to that shown in Figure 1
but the pipes 2 in Figure 7 are bent downward to bring them in the path of the
furnace gases. The superheater is usually placed in the hottest part of the flue
and in the case of a Lancashire or Cornish boiler is situated generally at the rear
end of the boiler so that the furnace gases issuing from the internal flue tubes C of
the boiler will impinge directly on the superheater. D is the perforated steam
collecting tube arranged as usual near the crown of the boiler shell and preferably,
in the case of Lancashire or Cornish boilers, near the rear end thereof. D' is a
pipe forming a communication between the tube D and the first box of the
superheater. E is another steam pipe for conducting the superheated steam from
the box to the ordinary stop valve F. It will be observed that the pipe E enters
the boiler again and traverses the steam space thereof but not the water space,
except in the form shown in Figure 6 where the pipe passes through the small
depth of water usually existing in the steam drum G.
In Figure 1 the steam pipe D' is shown passing out through the rear end plate
of the boiler, and the pipe E enters the boiler through the crown of the boiler
shell. In Figure 2 the pipe D' passes through the crown of the boiler shell, and
the pipe E enters the boiler at a point a little to one side of the crown. In this
case two stop valves H H are provided so that the steam can if desired be passed
directly to the main steam pipe of the boiler without being superheated, or can be
superheated and dried in accordance with my invention. When the steam is to be
superheated and dried, the valve H' is closed and the valve H is opened, and when
the steam is to be conveyed direct to the main steam pipe through the pipe J the
valve H is opened and the valve H is closed.
The arrangement of the pipes D', E in Figures 3 and 5 is similar to the
arrangement shown in Figure 1. In Figure 4 the pipe E is shown entering
the boiler through the rear end plate instead of through the cylindrical shell.
In the construction shown in Figure 6 the superheater is placed horizontally
immediately above the water tubes, and the pipe E conveying the superheated
steam from the superheater enters the steam drum and traverses nearly the full
length thereof twice before being connected to the stop valve F. The pipe Emay
be shorter than shown in the drawing.
In the construction shown in Figure 7 the pipe E for the superheated steam
communicates with a box K arranged within the steam space of the boiler and
connected with a similar box K' by means of a number of small tubes K². The
box K is in communication with the stop valve F. J is a pipe leading from the
pipe D to the main steam pipe L. H' is a stop valve in the pipe J. The two
valves H, H' and pipe J serve the same purpose as the valves H, H' and pipe J in
Figure 2.
It is obvious that in lieu of passing through the superheater the whole of the
steam generated in the boiler, a portion only of the steam may if desired be super-
beated and dried as above described such superheated steam being then mixed with
the steam which has not been superheated.

page_text: 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. The method of producing dry and superheated steam which method consists
in passing the steam from a generator through a superheater, and then through
pipes, tubes, chambers or coils arranged in the steam space of the generator,
substantially as described.
2. For producing dry and superheated steam, the means constructed substantially
as herein described with reference to either of the forms or modifications illustrated
in the accompanying drawings and operating as specified.
Dated this 20th day of December 1895.
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.