Year: 1894

page_text: Date of Application, 1st Oct., 1894-Accepted, 23rd Mar., 1895
A communication from CHARLES WHITING BAKER, Mechanical Engineer,
residing at 116, Midland Avenue, Montclair, County of Essex, State of
New Jersey, United States of America.
1, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
Chartered Patent. Agent, do hereby declare the nature of this invention and ió
what manner the same is to be performed, to be particularly described and
ascertained in, and by the following statement :-
This invention relates.to improvements in steam, boilers and it has for its purpose.
to improve and simplify the construction thereof and to secure greater economy in
the generation of steam, and the various features by which these ends are
accomplished will be pointed out hereafter..
In the accompanying drawings the preferred embodiments of the various features
of this invention are illustrated sufficiently to enable those skilled in the art to
practice the same, and it will be understood that the details of construction may be
varied without departing from the spirit of the invention, and that certain features
may be used alone or in combination with other features, according to the nature
of any particular case and the objects to be accomplished thereby.
Figure 1 is a side elevation of a boiler, the walls being in section..
Figure 2 is a transverse section showing the mode of setting.
Figure 3 is a horizontal section through the front.header.
Figure 4 is a front view of the header;
Figure 5 is an edge view of the header;
Figure 6 is a section of the header, showing the method of rivetting;
Figure 7 illustrates a rivetting tool;
Figure 8 is a section of a modified stay or brace;
Figures. 9, and 10 are sections and Fig. 104 a front view respectively of
modifications in the construction of the header;
Figure 1 is a sectional elevation of a portion of the rear end of the boiler;
Figure 12 is a section on line 12, Figure, 11;
Figure 13 is an enlarged section of the front end of the drum, showing the
steam-drier;
Figure 14 is a transverse section of the steam-drier;
Figure 15 is an enlarged longitudinal section and partial transverse section of
parts of the steam drier showing the method of returning the water to the boiler.
Figures 16 and 17 are details of Figure 13;
Figure 18 is a side view of two tubes and radiator sections ;
Figure 19 is a cross section of tubes and radiators:
Figures 20 21 and 22 are details of the radiators and supports;
Figures 23, 24 and 25 are details of a modified form of radiators and supports;
Figure 26 is a cross section of the tubes of a water-tube boiler having the
tubes- arranged in diagonal rows and provided with radiating plates between
the rows;
Figure 27 is a similar transverse section having the tubes arranged in diagonal
rows,
with separate radiating plates on the top of each tube;
Figure 28 is a similar view with the tubes arranged in vertical rows and with
radiating and deflecting plates among the tubes ;'
:

page_text: Figure 29 18 a sectional elevation of a vertical fire-tube boiler, provided with
radiators, and
Figure 30 is an enlarged cross section through one of the tubes and radiators
of Figure 29.
My correspondent has chosen to illustrate the invention in connection with a
typical form of steam generator such as is indicated in Figure 1, in which steam
is formed in the inolined parallel tubes t, flows forward and upward through
them to a front header F, and rises through this to an inclined steam drum D, but
which is not so greatly inclined as the tubes. The water is carried along with
the steam by reason of the buoyancy of the steam-bubbles. In the drum D,
the steam separates from the water which flows back to the rear ond and passes
down to the rear header G.
It is one of the purposes of this invention to make the velocity of the water
flowing in this circuit as great as possible, and this is done by making the
headers FG of much larger cross-section than has been customary in water-tube
boilers, and securing straight passages from the tubes to the drum D. This is
further effected by making the front header of somewhat less size than the rear
header G. The header F is reduced in area of cross section so that it is somewhat
less than the combined cross sectional area of the tubes t t, and while this tends
to slightly retard the flow, by increasing the friction, it tends on the other hand to
accelerate the flow to a greater degree, by renson of the fact that the suction of
the rising steam and water in the front header F will increase as the rising steam
forms a larger proportion of the total contents of the header..
The rear header G is preferably made of such a width that its section will
approximate or exceed the combined sectional areas of the tubes, and by thus
giving the tubes an ample reservoir to draw from, each tube is afforded a supply of
water proportionate to the rate of generation of steam, and the boiler is able to be
worked with much fiercer heat than in boilers with ordinary forms of headers, where
the flow is so restricted that the tubes nearest the top of the headers are apt by
their suction to interfere with the proper supply of water to the intensely heated
tubes in the lower rows.
The headers each consist of flat plates ppl and edged plates n, the inner plate
forming a tube sheet, and the outer plate p' having hand-holes opposite each
tube-end for the usual purpose. To take up the internal pressure tending to force
the two plates ppl apart suitable braces or stays aa are used between the main
plates and preferably consisting of flanged plates or channel irons, the flanges being
secured to the plates pp by bolts or rivets preferably the latter. In case the
tube plate is to be intensely heated, the supporting braces a, may be made slightly
shorter than the distance between the plates to avoid overheating the inner
platop through tlie-interference with the transfer of heat which occurs when the
Hange of the brace is in contact with the plate. This is shown in Figure 8 which
is enlarged, the brace a having a flange between which aud the plate pisn
washer w mounted on the rivet. To facilitate the rivetting of the braces a between
the plates a block 6 (Figures 6 and 7) may be slipped between the heads of the
rivets to hold the rivets while the ends are being headed, after which the block
is removed. It will of course be evident that other forms of braces may be used; as
stay-bolts etc.
b
After the braces are secured in position, the headers F G may be suitably
secured to the dram D, either in the shop or when the boiler is erected on the site
it is to occupy. The tubes tt are then inserted and expanded in the tube plates
at, each end and the hand-hole covers are put in place and secured. Any suitable
style of cover may be used for the hand-holes.
To further prevent the bulging of the plates pp midway between the braces a a
and with the further object of providing an orifice through which to direct a steam-jet
to blow soot and ashes from the tops of the tubes, a hollow stay bolt a' (Figures 3
and 4) is preferably inserted directly over each tube, and midway between it anl
the tube next above. This stay bolt may be made with a screw-thread and be

page_text: tapped through the sheets, or it may be expanded in each sheet, or otherwise
secured.
For the edges of the headers, the construction shown in Figures 3 and 5 is
preferred, consisting of a channel plate n with its flanges outward, said flanges being
rivetted to the plates pip. To support the web of this channel plate from being,
bulged ontward by the steam pressure, narrow cross-bars mare employed,
extending between the flanges of the channel plate, which hold the plates n from
bulging. For headers of considerable width however where the tendency to bulge.
would be considerable, the construction shown in Figures 9 and 10 is preferred;
in the former the plate which closes the end of the header, is bent to approxi-
nately a semi-circular form, and is subjected to tension by the internal pressure.
The tendency of the plates pp to bulge near their edges is resisted' by stays a².
In Figures 10 and 10 the plate is reversed in position, and acts as an arch to
resist internal pressure and stays a² are also used here to take up the thrust of
the plate n² and the pressure on the plates pp'. This last arrangement has the
advantage that it places both heads of the rivets in the closing seams outside the
header thus making it possible to make these seams by macliine rivetting.
While any suitable connection may be made between the drum D and the
headers and G, it is preferred to cut out pieces of the shell of the drum D at
the place of junction, and rivet flanges on the headers to the sholl of the drum, as
shown in Figure 11.
To resist the 'tensile strain due to the pressure on the opposite heads of the
drum D. stays a³, Figures 13, 16 and 17, extend across the opening and are
rivetted to the shell on each side. In order that these stays may obstruct the flow.
of the water as little as possible, they are made of thin strips and are turned so that
the part extending across the opening lies in a vertical plane as clearly indicated in
said figures.
To purify the water entering the boiler, from sediment and scale and collect such
impurities at one point, the rear header G, (Figures 1 11 and 12) extends cousider-
ably below the level of the lowest row of tubes and forms a settling-chamber G'
in which such sediment as forms in the circulating water is deposited. To purify
the water at its first entrance to the boiler and 'cause most of the impurities to bo
deposited in the settling chamber before passing into the circulation, there is
extended across the drum D a short distance below the water-line a large closed
pipe from which smaller pipes 9 g branch and extend down, each vertical"
chamber of the rear header G, being secured to the rear wall in any convenient
nanner. The feed water enters through the small pipe 9', with considerable
velocity and sucks with it water from the drum D, entering through the funnel g³.
This funnel is partly above and partly below the water-line g and thus the floating
scum and impurities on the top of the water are drawn in and carried downward
with the feed water into these pipes g, The entering feed water being mixed with
half or more of its volume of water at the boiler temperature, becomes considerably
heated, and as it moves slowly downward in the pipes g it acquires additional heat,
reaching nearly the full boiler temperature. When thus heated, the scale-forming
impurities in the water are largely precipitated and entering the rear header
just below the last row of tubes where the water is almost motionless, the heavier
particles drop by their own gravity into the settling chamber G2 from which they are
drawn off from time to time through the perforated pipe G³ or they may be cleaned
out by removing the hand-hole cover G.
To secure dry steam from drums of small diameter it has heretofore been
customary to take the steam from the steam come or from an upper steam drum, or
to run a "dry pipe" along one crown of the drum, perforated with holes, the object
being to take the steam from the point nearest the top of the steam chamber.
While these devices answer fairly well where boilers are worked with pure water
at moderate rates; it is one of the purposes of this invention to have the boiler.
furnish dry steam at all times, and this is effected by causing the steam in
flowing outward to take a circuitous course.
7

page_text: The means which my correspondent prefers to employ for accomplishing this are
shown in Figures 13, to 15, and comprise a separator K arranged in the top of
the boiler shell adjacent to the steam outlet pipe K. The separator K consists of
a pipe having inward baffle plates k against which the particles of water entrained
in the steam are thrown by inertia, as the steam pursues its winding course around
the plates or obstructions. It is preferred to make the portion of the pipe in
which the baffle plates are located of elliptical section, thus giving a greater width
of diversion of the course of the steam, without reducing the cross-section of the
pipe at any time below the cross-section of the outlet pipe K. The bottom of
the pipe I prefer to make inclined in the same direction as the flow of the steam,
so that the coudensed water collecting ou the bottom of the pipe will flow by
gravity and by the impelling action of the current of steam to the small sump or
reservoir K, situated just underneath the outlet pipe. The lower corners of the
baffle plates are preferably cut away, as shown in Figure 14, so as not to obstruct
the flow of the water along the bottom of the pipe.
The water collected in the sump or reservoir must be returned to the main body
of the water in the boiler, and various forms of mechanisms may be used for this
purpose, but a preferred construction is shown in Figure 15. The pipe K beyond
the baffle plates is made circular in form and at the end of the pipe where it joins
the vertical pipe K', a screw-propeller fan J is inserted, being. mounted on the
shaft J and being driven at a high velocity by the impact of the steam against
its blades. The object of this fan is first to furnish power for operating the
mechanism to drain the water in the trap back to the main body of water in the
boiler; and second any entrained water which has passed the baffle plates will be
thrown against the blades of the fan, and then thrown off them by centrifugal
force against the walls of the pipe. A rotating cylinder L. having its axis parallel
with the main pipe of the separator, is arranged in the sump or reservoir K² and is
rotated in a bushing L which has ninety degrees, more or less, of its circumference
on the top, and the bottom cut away. The inner rotating cylinder receives the
water from the trap when the opening is uppermost and empties it out as it turns
downward. This cylinder is operated by any suitable meaus, as for instance, by
the reducing gear or any other suitable mechanism operation by the fan.
While the mechanisin above described is preferred as a simple and efficient
means of drying the steam preparatory to its passage out of the boiler, the details
of the mechanism may be greatly varied without affecting the efficiency of the
devire.
My correspondent is aware that various styles of separators have been suggested
which have been attached to the steam pipes next the engine, and otherwise, but
such separators have necessarily been heavy and expensive having to sustain the full
boiler pressure and being outside of the boiler the hot water collected by then had
to be thrown away or piped back to the boiler, involving in either case considerable
loss of heat. This separator is arranged inside the boiler, where it can be made
very light and inexpensive, of thin sheet metal as it has practically no pressure to
withstand, and there the collected water will flow back to the boiler by gravity,
without loss of heat.
Experiments have shown that the ordinary tubes of generators, both fire-tube
and water-tube generators, can transmit a far greater proportion of heat from the
fire surface to the water surface than is transmitted in any of the ordinary
constructions. Various efforts have been made from time to time to utilize a
greater proportion of the heat developed in the combustion of the fuel than ordinarily
results, as by means of retaining the heated gases in contact with the tubes by
the adoption of tubes of peculiar construction and arranged in various ways,
and by departures from the ordinary forms of furnaces, but so fur with the best
instrumentalities employed, only a fraction of the heat that should be available is
utilized, and many of the means employed have resulted in such increased expense
in manufacture or use, or in such serious obstruction to the dralt, or in rendering
the cleaning of the tubes difficult, that practically but very little benefit has ensued,

page_text: while in most cases the means employed could not be used in connection with boilers
already constructed or of ordinary type.
In the course of many experimenta, it has become apparent to my correspondent
that the greater portion of the heat imparted to the tubular heating surface of
boilers from the heated gases was received by convection or direct contact of the
gases with the tubes, and that but a small percentage of the heat from the great
body of gases travelling within or passing the tubes, but not in direct contact
therewith, was conveyed to said tubes and to the water in contact therewith. Take
for example, the case of a locomotive boiler; although the tubes are of very small
diameter, two inches or less, and are usually ten feet or more in length, the
gases pass-through them so rapidly that they pass into the smoke-box and are
discharged while still at a temperature far above that of the water in the boiler.
The high velocity of the heated gases gives them no time to mix, by the process of
convection, in passing through the tubes, and consequently, while those particles in
direct contact with the tube become cooled, the highly heated gases in the central
portion of the tube cannot impart heat by contact with the tube, except as they are
displaced by the comparatively slow process of mixing, due to the friction of the
gases on tlie tube.
It has long been known that heated gases have almost no radiating power. Thus,
the heating surface in the fire-box of a locomotive boiler, which is exposed to the
direct radiation from the fire, makes many times as much steam, per square inch of
surface exposed, as does the heating surface of the tubes, which derive no heat from
radiation, and are practically heated only by contact with the rapidly moving gases.
In endeavouring to devise means by which the highly heated gases in the central
portion of the tube might be made to impart their heat to it, my correspondent
searched for some method of producing in the tube an equivalent to the radiating
action which occurs in the fire-box of a locomotive boiler. He discovered that this
could be effected with great simplicity and without detracting at all from the
efficiency of those portions of the gases which were in direct contact with the tube
surfaces, by immersing in the comparatively non-acting portions of the gases, plates
of such a character and so arranged as to radiate the heat thus imparted to them
directly to the tube surfaces, and by this means it is entirely practicable to utilize
a large proportion of the heat which would otherwise be lost. In order to render
this means of economically generating steam available in boilers of the ordinary
type, such as shown herein, the generators have been provided' with heating surfaces
of various styles and types, as hereinafter described.
Whatever may be the construction of the generator in which this improvement
is carried out, there is arranged within those generators or passages through which
the heated gases or products of combustion must flow from the fire-place to the
flue, plates, bars or similar devices, which my correspondent terms "radiators,”
and which are so placed that they will be heated by those gases which do not come
in direct contact with the boiler plates, and that the heat thereof will be radiated
as directly as possible to the surfaces of said boiler plates.
One form of such radiating plates or bodies, and the manner of arranging them
is shown in Figures 18 to 22, and consists in this instance of bodies S, of terra cotta,
fire-brick, or other refractory material, which are laid in rows on each pair of
tubest and are supported in any suitable way, as by bridges t' which span the space
between the tubes, and are placed at points between the radiators, each bridge piece
supporting the adjacent ends of two radiators. To keep the radiators S, centred
between the tubes tt a slot t³ is cut in the upper surface of the bridge piece, and
the lower wing of the radiator S is cut away at the end, as at s for a distance equal
to half of the thickness of the bridge piece.
In case it is desired to leave the horizontal passages between the tubes open to
facilitate cleaning from the side, the radiators and supporting bridges shown in
Figures 23 to 25 may be used, where the radiators S₁ are plain rectangular pieces
of a width no greater than the diameter of the tubes & and are supported vertically
midway between them by the bridge piece t³.

page_text: In Figure 26 is indicated a construction of water-tube boilers with tubes
diagonally arranged and the radiators are shown in the form of curved plates S
partially surrounding the tubes, but with the curves of the radiators concentric
with the tubes. These may be supported on rods T which extend across the row
of tubes, or in any other manner, and may extend to the bottom of the nest of
tubes, but it is generally preferred to stop them at the first horizoutal row above
the bottom row, as shown, to prevent overheating them by direct exposure to the
fire. Bridgo pieces or spacing blocks t may be used to hold them in the central
position.
In Figure 27 is illustrated a preferable form of radiating body, when the water
tubes are arranged diagonally, and upon each of the tubes t is mounted a vertical
plate S which is supported in vertical position by bearing plates to or otherwise,
resting on the curved top of a tube, and the sides bearing against the tubes in the
next horizontal row above.
In Figure 28 wherein the water tubes are arranged in vertical rows, the
plates Sare placed midway in the vertica! passages between the rows of tubes, and
are held in position by the pieces and may be supported by rods T or other
-convenient means. Projecting from the plates are deflectors & which serve to turn
the ascending gas currents and cause them to impinge against tube after tube in
succession, as well as to furnish additional surface for the absorption and radiation
of heat, and to stiffen the plates against warping or buckling. These deflectors
may be of any desired construction and width and arranged at any angle or
inclination and of any number, according to the amount of heating surface desired,
and the amount of deflection to be given to the moving gases.
In Figures 29 and 30, is shown an arrangement where the gases pass through the
boiler tubes and the radiators S are in the form of tubes arranged concentrically
within the boiler tubes, being secured in any suitable way.
It will be seen by these various forms of radiators that this invention is not
limited to any particular form, and that they may be arranged in different ways
and may be applied to generators already in use, being passed through the usual
furnace door and arranged in position, or through doors E, in the walls of the
furnace, or otherwise; nor do they interfere with the ready cleaning of the boilers
or tubes, and they can be made and applied at an immaterial expense in proportion
to the effect produced. They do not interfere either with the circulation of the
water or the direct heating action of the products of combustion, and it will be
evident that in proportion as they become coated and blackened by carbonaceous
deposits, their radiating efficiency is increased.
A further important advantage in connection with their use is the resistance of
the various channels or Leating flues through which the gases flow in passing from
the furnace to the chimney may be equalized, the radiators in those flues which
pass most directly to the chimney being so made as to offer greater obstruction
to the flow of the gases than is offered by the radiators in the more circuitous flues.
Having now particularly described and ascertained the nature of this 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. The construction and arrangement of the headers in connection with the
parallel tubes substantially as and for the purpose hereiubefore set forth.
2. The method and means of staying the opposite parallel surfaces of the headers
substantially as and for the purposes set forth.
3. The construction and arrangement of the means for stiffening the plates against..
bulging substantially as and for the purpose herein set forth.
4. The arrangement of stays with the openings cominunicating with the headers
substantially in the manner and for the purposes above set forth.
5. The construction and arrangement of the pipes extending from the mud drum
to the water-level and the means for introducing the supply water with water from.
the boiler substantially as and for the purposes set forth.

page_text: 6. The means for heating and purifying the entering feed water and collecting
the sediment comprising a pipe near the water-level inside the boiler arranged to
receive the water from the surface of the water in the boiler and means for
introducing the feed water into said pipe substantially as and for the purposes set
forth.
7. The method and means of separating the entrained water from the steam prior
to its exit from the boiler by leading steam through a pipo in the interior of the
boiler provided with obstructions and collecting the entrained water and returning
it to the boiler by mechanism impelled by the flowing steam substantially as and
for the purposes herein set forth with special reference. to Figures 13 to 15.
8. As a means for separating the entrained water from the steam prior to its'
exit from the boiler a pipe having baffle plates said pipe being attached to the outlet
orifice for the steam and having a chamber or chambers opened alternately to the
interior of the separator and to the steam space in the boiler, substantially as and
for the purpose set forth with special reference to Figures 13 to 15.
9. The within described improvement in increasing the efficiency of steam
generators, consisting in carrying the heated gases that are not in direct contact
with the boiler plates or tubes in contact with plates or radiators arranged in
proximity to the tubes throughout the generator and in position to radiate the
heat to said boiler plates or tubes.
10. The use of radiators arranged in connection with the boiler plates or
tubes for the purpose of radiating the heat to the said plates or tubes substantially
in the manner set forth with special reference to Figures 19 to 30.
11. The improvements in the method and construction of steam generators having
the objects herein set forth and for the purposes stated.
Dated thie let day of October 1901
W. P. THOMPSON & BOULT,
London, Nottingham, Liverpool, and Manchester,
Agents for the Applicant.
W. P. THOMPSON & BOULT,
London, Nottingham, Liverpool, and Manchester,
Agents for the Applicant.