Improvements in Steam Generators.
Year: 1895

page_text: Date of Application, 23rd Jan., 1895
Complete Specification Left. 23rd May, 1895-Accepted, 29th June, 1895
PRUVIDIONAL ST
Improvements in Steam Generators.
ROBERT BAIRD, 134 St. Vincent Street, Glasgow do hereby declare the
ature of this invention to be as follows:-
My invention relates to improvements in constructing and arranging a form of
water tube boiler that will more effectually use the products of combustion.
This is accomplished by placing rows of tubes between water and steam drums
30 that each row forms a division wall round which the products of combustion
must pass. By this means a number of separate flues may be formed having for
their surroundings water tubes.
These flues can be arranged that the hot gases from the furnace can be returned
from back to front and from front to back of the boiler until all the useful heat
has been taken up before being allowed to go to the chimney.
To admit of rows of tubes being placed close up to each other side by side and
directly connected with water and steam drums I reduce the ends that are fixed to
the drums by about one half of their diameter.
Thus say the end of a four inch tube is reduced to two inches so that there is a
clear space of two inches between each hole in the drum.
Where such tubes form an outer casing (that is having heating surface on one
side only) I keep them absolutely close but inside of the outer casing tubes--this
is not necessary as it is better to leave them slightly clear of each other. This
allows the heat to completely lap round them and lets the hot gases mix to some
It also
extent without disturbing the main body of the draught round the flues.
adds to the strength of the drums by leaving a greater space between the holes
made to receive the tubes.
The tubes forming such division walls I preferably keep straight-by doing so
I am enabled to have them screwed into the holes in the drums, which would not be
done if they were in a bent form as the bend would not admit of the tube being
turned.
In my improved steam generator 1 employ five water drums and one steam and
water drum. Four of the drums are preferably smaller in diameter than the
others. All the drums are used in a horizontal position and parallel to each
other.
The four smaller drums form the corners of a rectangle-with the steam and
water drum between the two top drums. The remaining drum being placed near
the centre of the rectangle. The top corner drums are connected with the bottom
drums by a row of tubes. Another row of tubes connect the steam and water
drum with the two top corner drums. As these tubes are laid up quite close along-
side of each other a casing is formed which closes the top and sides. The bottom
being left open for fire grate and ashpit.
Connection is also made with each of the five outer drums and central drum by
rows of tubes. The tubes running between the bottom of the ceutral drum and
each of the bottom corner drums form the firing place and is in the shape of a
partial triangle. The base of the triangle being the fire bars and the top the
bottom of the central drum.
From the top of the central drum a row of tubes run to the bottom of the steam
and water drum. Another row runs from each of the top corner drums to the
central drum. This leaves besides the firing place four flues or spaces round which

page_text: the hot gases may be made to circulate before going up the chimney and in case of
more than one boiler being used another flue passage can be obtained by placing
the boilers side by side. The smoke may then be turned between the two boilers
before going up the chimney.
Dated this 2nd day of To 1905
ROBERT BAIRD, Engineer, 134 St. Vincent Street, Glasgow, 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:-
My invention relates to improvements in constructing and arranging a form of
water tube boiler, that will more effectually use the products of combustion.
This is accomplished by placing rows of tubes between water and steam druins,
so that each row is a division wall, round which the products of combustion must
pass. By this means, separate flues are formed; having for their surroundings
water tubes. These flues are arranged that the hot gases from the furnace are
returned from back to front, and from front to back of the boiler, as often as may
be required to admit of the useful heat being absorbed, by the water heating
surfaces.
To admit of rows of tubes. being placed close to each other, side by side, and
connected with water and steam drums, I reduce the ends that are fixed to the
drums, by about one half of their diameter, thus, say the end of a four inch tube
is reduced to two inches, so that there is a clear space of two inches, between each
hole in the drum. Where such tubes form an outer casing, that is having heating
surface on one side only, I keep them absolutely close, but inside of the outer
casing tubes, this is not necessary, as it is better to leave them slightly clear of
each other. This allows the heat to completely lap round them; and lets the hot
gases mix to some extent, without disturbing the main body of the draught round
the flues. It also adds to the strength of the drum, by leaving a greater space
between the holes made to receive the tubes. The tubes forming such division
walls I preferably keep straight, by doing so I am enabled to have them screwed
into the holes in the drums, which could not be done if they were in a bent form,
as the bend would not admit of the tube being turned, when in close proximity to
others. The tubes may be expanded into the drums, in any of the ordinary ways,
or they may be fixed by couplings, one method of which is illustrated on accom-
panying drawings. When connection is made in this form any tube can be
removed and replaced without disturbing the others.
In order to more fully explain the particulars of my invention, I shall now refer
to accompanying drawing.
In
Fig. 1. represents a cross vertical section of two boilers, placed side by side.
each boiler employ five water drums, and one steam and water drum, marked
respectively. c. c. c. c. b and a. a. is the steam and water drum, b. what I shall
hereinafter term the central water drum, and c. c. c. c. the corner water drums.
Connection is made between the drums by tubes marked d' d² d³d and i. The
fire bars are marked m. The furnace space g. Flue spaces f. f. and e. e. Sections
of baffle plates in top corner water drums c. c. are marked j.
Fig. 2 shows a longitudinal section of one boiler at the markings A. A. on Fig. 1.
The same letters of reference indicate corresponding parts in Figs. 1 and 2. The
cross section Fig. 1. is at the markings B. B. on Fig. 2.
Fig. 3 shows the end of ferrule do with squared hole, in which a mandrel may be
inserted, to turn the ferrule tightly into its place in the end of tube.

page_text: Fig. 4. is a partial section of a tube, having the end reduced in diameter, and a
method of fixing the tubes to steam or water drums, by means of screwed ferrules
marked d³.
1
In order to form an outer casing for each boiler, which will partly exclude the
surrounding atmosphere, and at the same time be a steam producing surface on one
To accomplish this, and
side, I keep them close to each other as at d¹ Fig. 2.
connect the tubes with the drums in rows, without having the connecting holes in
too close proximity to each other, I reduce the ends of the tubes, as shown at d.
Fig. 4.
The reduced ends having also the effect of retarding the circulation of the
water in the tubes, and thus having a tendency to prevent priming, and insuring
more steady delivery of steam producing water, to the steam and water drum a.
The tubes d¹ between the corner drums c. c. c. c. Fig. 1. are placed quite close
to each other, in a continuous row, this, with the exception of where the ends of
the tubes are connected with the drums, closes-in two sides of the boiler. The
steam and water drum a, and the top water drums c. c. nearly close the top.
The remaining space being partially filled in by the short tubes i. Thus two sides,
and top of the boiler, are steam producing surfaces, which with very little stopping
or lagging exclude the surrounding atmosphere.
The back end of the boiler is closed up with a thick wall of fire bricks, as at l.
Fig. 2.
The openings to the flue passages at the front, are covered with movable
The space below the
casings or doors, so as to give access for cleaning purposes.
bottom water drums c. c. is closed all round, except the front, which is the ash-pit,
below the fire bars.
Having now particularly described the outer parts of the boiler, I will proceed
to describe the internal arrangement of flues, and combustion chambers. From
each of the bottom water drums c. runs a row of tubes d' connecting with bottom
of the central water drum b; these tubes extend to beyond the fire bridge n. on
Fig. 2. and are not kept quite so close to each other, as the outer casing
tubes d'. A little space is left between each, so as to admit of a slight mixture
of the hotter gases of the firing place, with the gases in the adjoining flue, but
not enough to disturb the main body of the draught. The triangular space g.
on Fig. 1. is the furnace, having for its bottom fire bars m, sides, water tubes d*,
top, bottom of water drum b. Between the back of the fire brick end, and the
tubes is an opening on each side, where the flame splits, and returns to the front
of the boiler by the flue passages f. f, when it may be made to return again to the
back, by flue passages e. e. and to the front again by the space between the boilers h.
thence to the chimney r. by the smoke casing P. The tubes & connect the top
corner water drums, with the central water drum b, and the tubes d³ the top of
At either end of
central water drum b. with bottom of steam and water drum a.
the top rows of tubes a space may be left, by keeping out a few tubes, round which
the products of combustion may circulate on the way to the chimney; or the tubes
may be kept slightly apart, between which the hot gases may penetrate from one
flue passage to another.
To assist the circulation of water, I place baffle plates, as shown at j. in top
5 corner water drums c. c. This has the effect of more readily causing a portion of
the water from central drum b, by way of the tubes d, to return by tubes d¹, to
bottom corner drums c. c. Although not shown on the drawing, I may also place
The
a baffle plate above the tubes connected with the steam and water drum.
tubes may be expanded or screwed into the drums, or fixed by means of ferrules,
O as shown on Fig. 4. The ferrule d' has a countersunk head fitting into a
The
corresponding seat in the hole through which it passes inside of the drum.
bottom end of the ferrule is screwed as also is the inside of the reduced end of the
tube. The ends of the tubes are turned with a true face, and a corresponding face
is made round the outer edge of the hole through which the ferrule passes, so that
55 when the ferrule is passed through the drum, and screwed up tight, a metal to metal
joint is made. When the tubes are connected to the drums in this way, they can
easily be removed and replaced, without disturbing the others.

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 ;
1st. A steam generator having rows of tubes arranged between water drums, and
steam and water drum, as described and illustrated.
2nd. Tubes having reduced ends, for the purposes herein described and
illustrated.
R. BAIRD.