Year: 1886

page_text: I, GEORGE FREDERICK REDFERN, of the General Patent Office N° 4, South
Street, Finsbury, in the County of Middlesex Patent Agent, do hereby declare the
nature of this invention (a communication from abroad by Frank Clarkson
Garbutt, of Sherman, Texas, United States of America) and in what manner the
same is to be performed to be particularly described and ascertained in and by
the following statement:-
The object of the invention is to provide a cheap, durable and effective, as well
as simply constructed, steam generator, in the operation of which a forced cir-
culation of water shall be effected, and in which the quantity of water exposed to
a given area of heating surface shall be greatly reduced, the tendency to foaming
be diminished, and the level of the water in the boiler, or steam chamber, shall be
below the surface of the water in the water tubes around the fire tubes, the object
being to get large steam space and to prevent liability to raise water to the steam
supply pipe.
The invention refers especially to improvements on a patent granted to Benjamin
Brazelle, dated 26th April 1881 N° 1798 for steam generators, wherein a natural
circulation is effected.
To this end the improvements consist in an upright cylindrical or oblong shell
closed at both ends, and adapted to be located above a furnace, one or more fire
tubes traversing said shell, a steam receptacle located within the shell com-
municating with a water chamber below one or more water tubes, each surrounding
a fire tube, and a force pump, which forces a circulation of water from the steam
chamber through the water chamber and water tubes back into the said steam
chamber. The water, by its rapid circulation through said water tubes, being
rapidly converted into dry steam by continually coming in contact with the large
heating surface of the fire tubes.

page_text: In order to fully describe the improvements, and to enable others skilled in the
art to fully understand the same, reference is had to the accompanying drawings
in which:
Figure 1 is a vertical central section of an upright steam generator, embodying
the improvements, and on line 1, 1, of figure 2. Figure 2 is a plan section of the
same on line 2, 2, of figure 1.
Figure 3 is a vertical central section of a steam generator, showing a modified
form of the improvements and as applied to a horizontal, or locomotive boiler.
Figure is a vertical cross section of the same on line 4, 4, of figure 3.
Referring to the first two figures of an upright boiler, A is a cylindrical or oblong
shell of iron, or steel plate, which is closed at top and bottom by flanged heads a, a¹,
the lower of which, a', is preferably placed a short distance above the end of the
shell, see figure 1, to form a combustion chamber, and in such case is usually
connected with an inner ring, a², which is united at the bottom to the shell in the
usual manner. The shell A is located above and supported upon a correspondingly
shaped furnace B, provided with a grate b, fire box b¹, ash pit b², and ashpit
door 63, and having suitable lining of fire brick or other non-conducting material.
The beads, a, and a¹, are connected by a series of fire tubes a³, through which the
products of combustion pass to the uptake a', to which is connected an exit flue a³.
Thus far the above described construction of the steam generator is the same as
in the patent above referred to.
A flanged head c, of a shape to correspond with the shape of the shell A, is riveted
to and made steam tight with the shell between the heads a, and a', thereby dividing
the shell into an upper and lower water chamber d and d¹, the upper portion of
the former and larger chamber d, constituting a stea'n space E. Passing from the
lower water chamber d' through the flanged head c, and extending up into the
steam chamber E, are a series of water tubes ɖ³, having free open upper ends, each
water tube surrounding and concentric with one of the fire tubes a³, so that an
annular water space is formed between each fire tube and its encircling water tube.
A return pipe e, at the outside of the boiler, or cylindrical shell, connects the upper
water chamber with a force pump F, by which the water is drawn from said upper
chamber and forced through the pipe e¹, from the pump into the lower water
chamber d', and forced to circulate through the latter up through the water tubes
surrounding the fire tubes, running over at their free open upper ends, and dropping
down into the upper water chamber, where it is taken out by means of the pump
and again forced into the lower chamber, thus continually repeating the operation
of circulation, as indicated by arrows in figure 1.
G are aprons of plate metal, see figures 1 and 2, extending from the upper head a
down below the free open upper ends of the water tubes, and between the latter
and the shell A, and may be made to extend around as far as desired to prevent
water from splashing into the steam supply pipe, guage pipes &c.
g is a flange on the upper end of the aprons, by which they are riveted to the
head a.
The pump may be provided with a three-way cock h, to connect the
pipe e with the water supply pipe e², when the pump supplies the boiler with
f.esh water; the pump thus serving two purposes. His the steam supply pipe
for the engine, H₁ the steam supply pipe for the pump, I the steam guage, I¹ the
water guage, 12 the safety-valve, and I³ the water discharge pipe.
In the modifications shown in figures 3 and 4, for a horizontal, or locomotive
boiler, A is the cylindrical shell, which in this case is placed horizontally, having
the two heads a and a', one at the front and one at the back; the back or rear
head a¹, forming the back wall of the furnace, or combustion chamber B, and
extending around to form the top, or crown, and the front wall of the furnace, as
usual, see Figure, 3; the forward head a, forming the rear head of the smoke box,
or chamber a. The two heads a, and a', are connected by a series of fire tubes a³,
(now placed horizontally), through which the products of combustion pass to the
swoke box, and thence out of the smoke stack a³. Flanged heads c and c¹, are

page_text: riveted to and made steam tight with the shell A, between the heads a and a¹,
thereby dividing the shell into a front and rear water chamber d and d¹; and the
space between the heads c and c¹, less that portion thereof which is occupied by the
tubes, forming a separate water chamber E, the upper portion of which constitutes
a steam space E¹. Connecting the two water chambers d and d¹, are a series of
water tubes d², each surrounding and concentric with one of the fire tubes a³, so
that an annular water space is formed between each fire tube and its encircling
water tube; H is a pipe connecting the two water chambers d and d¹, near the
top at about the normal water line of said chambers, Through this pipe the water
and steam in the rear chamber d¹ passes into the front chainber d. h are one or
more openings in the head c near the top, somewhat below the water line, in the
chamber d, through which the water and steam in both chambers, & and d¹, enter
the main steam chamber E¹. I is a draw pipe, through which the water is drawn
from the chamber E, by means of a force pump and forced by said pump through
the supply pipe I, into the rear water chamber d', thence through the water tubes d'
surrounding the fire tubes a³, and through the tube or pipe H, into the front water
chamber d, thence with the steam through the openings back into the steam
chamber E', from whence the operation is repeated, and thus a constant and rapid
circulation of the water is secured. The supply of steam to the engine, or cylinders,
is taken from the steam chamber E¹ by means of the steam supply pipe h¹.
In operation a constant and rapid circulation is induced by the action of the
heat upon the water in the annular spaces surrounding the fire tubes, which cir
culation is still further increased by the force pump, the currents ascending through
said spaces into the second chamber, and descending through the return water pipe
of the pump. The steam generated passes into the upper steam space or chamber
as described.
In addition to the provisions of superior facilities for circulation, a capacious
reservoir of dry steam is substituted for the unduly large water spaces existing in
tubular boilers of the ordinary construction, materially reducing the volume of
contained water as compared therewith, and correspondingly facilitating the free
and rapid generation of steam. The thorough and rapid circulation also prevents
accumulation of scale or deposit in the tubes, and the provision of a separate steam
chamber effectually obviates foaming, even with an exceptionally high water level.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare that what
I claim is :-
1. The combination with a steam generator constructed of a shell, closed at both
ends, having a fire tube or tubes traversing said shell and a steam receptacle located
within the shell surrounding the fire tube or tubes, of a series of water tubes, each
surrounding one of the fire tubes, said water tubes having free open upper ends,
and connecting the supply water chamber with the steam chamber as and for the
purpose set forth.
2. The combination in a steam generator constructed of a shell closed at both
ends, having a fire tube or tubes traversing said shell and a steam receptacle
located within said shell surrounding said fire tube or tubes, of a series of water
tubes each surrounding one of the fire tubes, said water tubes having free open
upper ends and connecting the supply water chamber with said steam receptacle or
chamber, with an apron or aprons suspended from the upper head of the shell
between one or more outer water tubes and the shell, and down below the open
ends of said water tubes as and for the purpose set forth.
3. The combination in a steam generator constructed of a shell closed at both
ends, having a fire tube or tubes traversing said shell, and a steam receptacle located
within the shell surrounding the fire tube or tubes, of a series of water tubes, each
surrounding one of the fire tubes, said water tubes having free open upper enda
and connecting the supply water chamber with the said steam receptacle, with a

page_text: force pump substantially as herein shown and described, and for the purpose set
⚫forth.
4. The combination, in a steam generator constructed of a shell closed at both
ends, having a fire tube or tubes traversing said shell and a steam receptacle
located within said shell surrounding said fire tube or tubes, of a series of water
tubes each surrounding one of the fire tubes, said water tubes having free open
upper ends, and connecting the supply water chamber with said steam receptacle
or chamber, with an apron or aprons suspended from the upper head of the shell
between one or more outer water tubes and the shell and down below the open
ends of said water tubes, and a force pump, substantially as herein shown and
described and for the purpose set forth.