IMPROVEMENTS IN STEAM BOILERS AND IN STEAM JOINTS
Year: 1880

page_text: LETTERS PATENT to Ernest August Bourry, of Saint Gall, in the Republic.
of Switzerland, Civil Engineer, for an Invention of "IMPROVEMENTS IN STEAM
BOILERS AND IN STEAM JOINTS."
COMPLETE SPECIFICATION filed by the said Ernest August Bourry at the
Office of the Commissioners of Patents on the 14th May 1880.
r
ERNEST AUGUST BOURRY, of Saint Gall, in the Republic of Switzerland, Civil
Engineer. "IMPROVEMENTS IN STEAM BOILERS AND IN STEAM JOINTS."
The main purpose in the present construction of water-tube boilers is the
reduction of weight to the lowest possible limit by employing but small thicknesses
of material throughout, and yet combining unquestionable safety, together with the
exclusion of all heated surfaces, which are not steam producing. Based upon the
well known fact that the smaller the diameter of a tube is, the thinner its material
may be for a given internal pressure, it has been contrived in a particular, and
most characteristic way to set boilers together in their entirety, with tubes only of
comparatively small diameter, in such a manner that with these alone the
combustion chamber, the flue or flues, and the walls of the boiler in general are
constructed with the help of connections and joints of an entirely novel kind,
provision being thus made to turn to useful account the beat otherwise lost by
radiation. To enable other persons of the profession to construct and work said
water-tube or tubulous-sided steam boilers, I shall herewith give a full explanation
of their mode of construction and use, referénce being had to the accompanying
Drawings, and the letters of reference marked thereon, the same letters designating
the same parts throughout. Plate I., Figure 1, is partly a front elevation, and partly a
vertical section of an upright water-tube sided steam boiler; Figure 2 is partly a
plan and partly a horizontal section of it; Figure 3 shows five times enlarged the
connections and joints adopted and used for the construction of said boiler.
Plate II. shows a boiler on the same principle as the former, but laid horizontally,
and provided with such modifications as its position requires; Figure 4.is a longi-
tudinal elevation; Figure 5, two half sections cut at different places; and Figure 6,
half a front view and half a back view of it. Plate III. represents the same as in
Plate II., with the difference however that it is almost as if the preceding were
cut across in two, and the parts laid one above the other, becoming thus of the
return flue-class. The relative Figures 7, 8, and 9, follow the same order of things
as in the former Plate. The most striking peculiarity in the present construction
is the formation of the very walls or boundary of the whole boiler by rows of tubes

page_text: (in close longitudinal contact), and at right angles to each other, fastened to the sides
of somewhat larger tubes, whereby a square looking box-like body is established, the
larger tubes forming the corners, and the rows of smaller tubes the sides, so that I
may call the former corner tubes and the latter side tubes. The contents of all
these tubes together constitute the water spaces between the fire-side and the outer
atmosphere. Within the hollow space bounded by four such tube-walls are
superposed rows of still smaller tubes (called cross-tubes), connecting pair by pair the
corresponding side tubes opposite each other, and between which the fire and heated
gases are made to pass. The connections and joints adapted here differ greatly
from all those hitherto used and combine rapidity of execution with complete
lightness and cleanliness, being purely metallic, no paste whatever being required,
and securing an easy reopening for inspection and exchange, without damage
to the faces of contact, hence allowing to repeat these operations indefinately.
In order to preserve the valuable advantage of accessibility without loss of heat
by radiation and any sensible addition of weight, the usual casing of non-
conducting material is replaced by a jacket of thin sheet metal leaving a certain
layer of air between, by a current of which the radiated heat from the boiler is
carried off and led through the grate to the fire, in which way it, is completely
turned to profit again, while the surroundings remain comfortably cool, an
appreciable advantage on board ships or in other limited rooms. The annexed
Drawings clearly illustrate the way in which the above is to be executed and
obtained. In Plate I., Figures 1, 2, and 3, A, A, are the corner-tubes, furnished with
adequate bosses along their sides, into which are secured the side tubes B, B, by
tapped ferrules a, a. A certain number of said tubes B are also provided with
bosses for the reception of the cross tubes C, C; the others remain flusb, with the
exception of the necessary enlargement at one extremity for their connection, and
two longitudinal ribs place the centres of the side tubes further apart and facilitate
the adjustment of one on another. Dis the fire door; E, E, are pedestals for
elevating the boiler; F, a foot-plate upon which rests the grate G, and hangs the
ashpit H; ff, are blow off cocks at the base of the corner tubes, the widened pro-
longations J, J, of the latter serve as steam spaces; K. is the uptake, and L the
chimney or smoke pipe. The jacket M surrounding the whole reaches from the'
foot-plate F up unto the coverflanges of the steam space, where it is provided with
a cover encircling the chimney, and having air holes d, d, capable of being opened
more or less to regulate the admission of air. Between the lowest side tubes and
the foot plate a space is left open on all four sides for the passage of air from the
jacket, which air has been heated by the radiation of the boiler, and enters inside
beneath the grate to be employed for combustion. The junctions are made in the
following way :- -The bosses of the corner tubes are tapped inside; so is also the
widened end of the side tubes for a limited distance. Further on a very smooth
cone is made tapering towards the inside of the tube; the ferrule a, which is
provided with a little socket at its end, receives therein a well fitting ring b of
copper or other soft metal, the outer diameter of which corresponding exactly with
the base of the cone in the side tube. On screwing in the ferrule the ring b is
pushed forward and forcibly compressed within its socket, and this is continued
until complete tightness is obtained. At the same time another similar ring c in a
socket made on the inside of the corner tube boss is also compressed by the action
of a conical part of the ferrule; the said two rings, by their particular position, cut
off all access of steam or water to the screw thread, whereby the latter is secured
against oxidation, and does not offer any exceptional resistance to unscrewing.
The screw plugs P and p closing the holes through which access is had to the con-
nections, and which also serve for cleaning, are likewise provided with a cone
compressing a like ring as above for making a tight joint, and being also situated
on the water or steam side of the screw thread to preserve the latter against
deterioration. It will be seen by the above description that the compression of the
interposed body for effecting tightness is not taking place in the direction of the
axis as usual, but either radially or concentrically. It has to be remarked that these*

page_text: joints have mainly been devised for the present boiler construction, and must be
considered as an important part of this Specification. The horizontal or marine
boiler illustrated in Plate II., although specially designed for places which
require a small height, is also applicable for stationary purposes, and under
many other circumstances. A, A, are again the corner tubes; B, B, the side
tubes; and C, C, the cross tubes. The hollow spheres 0, 0, belonging half to
the water space and half to the steam space, are intended to obviate all fatal
undulations in the total water level arising from the motion of a ship or from
differences in the degree of ebullition along the boiler. The cylinders N, N,
contain nothing but steam, and are connected to the spheres by elbows to give the
necessary flexibility for unequal expansion; K is the uptake attached to the smoke
box, which reaches into the boiler to where the cross-tubes commence from that
side; it is made to keep off the contact of the heated gases with the last couples of
side-tubes in order to favour the return current of the water therein; L is the
smoke pipe. The grate G consists here of a certain number of parallel water tubes
lengthways with the boiler, and terminating at each end in larger tubes which run
across; of these only one is connected to the sides of the boiler forming the water-
spaces, the other is merely supported in its middle by the feed water pipe, to admit
of a free expansion and contraction of the whole grate; the feed water is first
directed from behind through the grate before entering the boiler, as by its lower
temperature it prevents the presence of two much steam in the grate tubes and
preserves them best from burning through; R, R, are baffle plates vibrating
round the corner tubes A', A', and serving to direct the air current at will up or
downwards through the grate, in which latter way the furnace becomes smoke-
consuming, and affords also greater facility in stoking. The left side of Figure 5
shows the relative position of said plates for the up and the right side for the down
current. The air between this boiler and its jacket may, with the same advantage
as in the upright boiler, be caused to flow when heated by radiation through the
burning fuel, in which case the front plate with the fire door is made double, and
similar to that shown in the next combination, its omission here being for the
purpose of showing different arrangements. On Plate III. is represented a marine
boiler calculated for such cases where a reduction in length is more important than
in height, as in many large steam ships. This boiler is divided into two stories,
the lower forms only half a square, but can also be completed to a whole one, if
desired, the upper story as return-flue is destined for the reception of the cross-
tubes; the central tube A" serving as a corner tube collectively to both stories,
reaches from the front as far back only as the space occupied by the cross-tubes,
from thence the two respective side tubes on both sides are reduced to one uniting
directly the two outer corner tubes A¹¹ situated perpendicularly above each other,
as is to be seen in the left half of Figure S, in which way the back connection is
produced, the same shape of the last mentioned side tubes is maintained out to the
end of the boiler, and a certain number of them are separated from the circuit of
the flame by a removable cross partition rising up from the end of the grate, as
indicated by the dotted lines, said tubes are reserved for the return current of the
water. By this arrangement easy access is had for cleansing the surfaces from soot,
the back of the boiler being provided with a door. In this boiler a second series
of spheres Q, Q, are applied for the steam space through which the steam reaches
the upperinost collecting tube, whence the steam is taken for use; it is however
evident that the steam space can also be constructed here as in the preceding
combination.. The front piece with the fire door and ashpit door is made hollow
for the reception of air subsequently used for combustion. The air is thus first
warmed by the radiation of the inside face, keeping cool the front. It may be taken
from the outside but better from the space between the boiler and the jacket, as
explained with the vertical boiler, making also use of the radiated heat therein;
moreover to promote the comfort of the men on duty and economise still more, the
uptake K may also be made double with a layer of air between the plates, carrying
off likewise the heat radiated here to the benefit of the combustion.

page_text: E
Having thus explained the bases of this boiler construction and the improvements
indispensable to secure the desired completeness, I shall proceed to point out what
I consider and claim to be new and my Invention,―
1. The formation of the flue or flues and the walls in general of boilers by rows
of tubes close to one another and inserted at right angles into the sides of larger
tubes, the section of the boiler forming a rectangle or rectangles, or parts of
rectangles, traversed or not by rows of smaller tubes in one or both directions.
2. The seizure of the radiated heat from boilers, ovens, kilns, &c., by an air
current, and its conveyance to the fire for re-employment in the combustion.
3. The tightening of connections, couplings, plugs, &c., by radial or concentric
compression of a confined metallic ring through the action of cones, substantially
as above set forth.
In witness whereof, I, the said Ernest August Bourry, have hereunto set
my hand and seal, this Fourteenth day of May, A.D. 1880.