Improvements in or relating to Steam Generators.
Year: 1893

page_text: COMPLETE SPECIFICATION.
Improvements in or relating to Steam Generators.
A communication from CHARLES HENRY SHAW, of the City of Denver. County
of Arapahoe, State of Colerado, Corner of Wazee and 35th Streets, U.S.A.,
Mechanical Engineer.
I ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex
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 steam generators, and more particularly to that class of
steam generators of the sectional water tube type.
The objects of this invention are to produce a water tube steam generator which
shall be safe to operate, and shall be economical in use, that shall furnish a free,
unobstructed and direct circulation, that shall have sufficient water space to furnish
a constant supply for the descending circulation, and a large water surface for the
delivery of steam into the steam chamber, that shall have a large amount of
steam space, that shall be simple of construction, and easy to get at for cleaning
and repairs.
To these ends the invention consists in a steam generator embodying the features
of construction, arrangement and having the mode of operation substantially such
as is hereinafter more particularly pointed out.
Referring to the accompanying drawings in which an embodiment of this invention
is illustrated,
Figure 1 shows a large front elevation and a part sectional end view on the
lines 1-1, Figure 2 ;
Figure 2 is a side elevation, the brickwork being removed to clearly show the
construction and arrangement of the parts of the generator;
Figure 3 is a detailed enlarged sectional view of the metallic ring joints and
bolts.
Figures 4 and 5 are detail views showing a modification.
As above intimated the invention involves a water tube steam generator in which
by means of certain features of construction and forms and arrangement of parts,
my correspondent is enabled to provide a boiler fulfilling the objects of the
invention above stated in an essential and practical manner, and the various
features of construction and arrangement will now be described whereby these
objects are attained.
It may be remarked in general that the boiler is shown as mounted in a
conventional way having the usual brickwork supports in which are mounted the
usual doors for supplying fuel, removing ashes, and inspection of the boilers, and it
is not deemed necessary to describe these features in detail, as they are mere
accessories, and their general features of construction and arrangement are well-
known to those skilled in the art.
The generator comprises a number of cylindrical chambers A arranged at the
front and rear portions of the boiler, and serving as a means for supporting the
connecting tubes B. These chambers may be made of various materials preferably
of cast steel and should be of such a character that they are capable of withstanding
high pressure.
The tubes B are arranged in groups, each group consisting of a number of small
tubes having their ends connected to the chamber A by expanding the ends of
the tube in the openings a formed therein, and while a different number of tubes
can be grouped together, it is found convenient and desirable to arrange a series of
openings in a circle as six, and a single one in the centre of the circle, so that each

page_text: group of tubes consists of seven small tubes, having their respective enus united
in a single chamber A.
There may be any desirable number of these groups of tubes according to the
purposes for which the generator is to be used, but it will be observed that each
group or any number of groups of chambers and tubes form a complete generating
and circulating system
These groups of tubes are of the desired size, length and number and are suitably
mounted and connected together preferably in the manner hereinafter set forth,
and above each group or series of groups is arranged a plain cylinder tube or series
of tubes C, and these tubes are connected to the circular heads or chambers A at
each end, so that they may readily be connected to the group or groups of tubes.
Above these plain cylindrical tubes C is arranged a steam drum D at right
angles to the groups of tubes, and this steam drum is provided with the usual safety
valve D or other appliance while below and preferably at the rear of the groups of
tubes is arranged a mud drum E.
The circular heads or chambers A carrying the groups of tubes, as well as the
plain cylindrical tubes are provided above and below with metallic ring joints by
means of which any number of groups of tubes may be readily united, and while
these joints may be variously shaped, it is preferred to form them in the manner
shown in Fig. 3, in which the bearing surface or edge of each ring joint F is
grooved as at Fi, for the reception of the ings F2 and are provided with pro-
jections having bolt holes for the reception of the bolts f¹, whereby the sections
can be readily and securely joined.
The cylindrical chambers are also provided with threaded plugs H or man-hole
heads H which are accessible from the outside, and by means of which the tubes
can be readily cleaned. The groups of tubes being thus united are arranged over
the usual grate, and interposed between each layer or row of groups of tubes is
arranged fire-brick tiling II &c., extending nearly the entire length of the tube,
and leaving a space at one end of each group alternately for the purpose of carrying
the products of combustion throughout the length of the several series of groups of
tubes, and the cylindrical tube to the combustion exit.
Such being the general construction and arrangement of the generator it will be
found that the objects aimed at are accomplished, in that by making the generator
in sections and these sections of small diameter, it is almost absolutely safe under
very high pressure. Futhermore, great economy in fuel is the result of presenting
the water to the action of the fire in small bodies, and in this construction the
water circulates through the fire-chamber in the small tubes of the groups which
are preferably not over three inches in diameter, and as the products of combustion
are controlled and directed by the tiling I, to impinge upon each and all of the
tubes, the greatest economy is produced, and the heat and gases are prevented
from passing away through the smoke-stack until all the available heat has been
utilized.
Furthermore by this arrangement, a free unobstructed and direct circulation of
the water is obtained, as the heat applied to the small tubes of the groups causes it
to ascend through the front chamber A, and to pass into the top and large
cylindrical tube C from whence it passes to the rear chambers A and down through
these chambers and distributes itself to the small tubes B. The large size of the
opening between the chambers A. and the unobstructed flow of the water through
the large cylinder C, reduces the velocity at which the water travels, thereby
giving a water line that is comparatively steady, and free from agitation, and there
is a sufficient space to furnish a constant supply for the descending circulation and
a large water surface for the delivery of steam into the steam chamber.
In use the rear portions of the plain cylinder C are preferably kept constantly
full of water, the water line extending from the front head of the cylinders to a
point a little in front of the middle of the cylinder, and this not only gives a full
supply of water to the chambers and tubes below, but furnishes a large surface for
the delivery of steam and tends to reduce the agitation at the water line. The

page_text: steam drum extending at right angles to the large cylinders in connection with the
space in the cylinders above the water gives adequate steam room.
It will also be seen that the construction of the boiler is exceedingly simple, the
generator being made in small sections, each composed of a front and back chamber
to which the small tubes constituting each group are connected, and these sections
can be readily transported and secured together when the boiler is set up, and by
the use of the threaded plugs all parts are easy of access for cleaning and repairing,
and for the removal and replacing of any of the tubes when necessary, and the
whole arrangement has been found to be efficient and economical.
Having now particularly described and ascertained the nature of the said inven-
tion as communicated to me by my foreign correspondent, and in what manner the
same is to be performed, I declare that what I claim is ;-
1. A sectional steam generator comprising a series of circular groups of tubes
each group of tubes being provided with a circular head or chamber at each end,
and the heads or chambers being provided with metallic ring joints by means of
which they are united to form the generator substantially as described.
2. A steam generator comprising a series of circular groups of small tubes each
group being provided with a circular head or chamber at each end, the heads or
chambers being provided with metallic ring joints by means of which they are
united and also having the threaded plugs at their outer end substantially as
described.
3. A steam generator comprising a series of groups of small tubes each group
consisting of a number of tubes connected at their ends by hollow chambers the
chambers being provided with metallic ring joints a series of plain cylinders also
provided with chambers arranged above the groups of tubes and parallel thereto a
steam drum arranged above the plain cylinders at right angles thereto and a mud
drum arranged below the groups of cylinders substantially as described.
4. The combination with a suitable fire-grate of a steam generator comprising a
number of groups of tubes arranged at an angle each group being connected to a
cylinder at each end each cylinder having metallic ring joints by means of which
they are connected together and provided with screw plugs at their outer ends a
plain cylinder provided with chambers at each end arranged parallel to the groups
of tubes a steam drum arranged above the plain cylinders at right angles thereto
and connected by metallic ring joints and tiling arranged above each series of
groups of tubes leaving a space at one end of each group alternately the whole
being constructed and arranged substantially as and for the purposes set forth.
Dated this 30th day of May 1893.
W. P. THOMPSON & BOULT,
Agents for the Applicant.