IMPROVEMENTS IN AND APPLICABLE TO STEAM BOILERS, MORE ESPECIALLY OF THE LOCOMOTIVE CLASS
Year: 1880

page_text: LETTERS PATENT to William Phillips Thompson, of the Firm of W. P.
Thompson and Co., Patent Agents, 6, Lord Street, Liverpool, in the County of
Lancaster, and 323, High Holborn, in the County of Middlesex, Civil Engineer,
for an Invention of "IMPROVEMENTS IN AND APPLICABLE TO STEAM BOILERS,
MORE ESPECIALLY OF THE LOCOMOTIVE CLASS." A communication from
abroad by Monsieur George Maréchal, Engineer of Arts & Manufactures, Paris,
in the Republic of France.
PROVISIONAL SPECIFICATION left by the said William Phillips Thompson
at the Office of the Commissioners of Patents on the 2nd February 1880.
WILLIAM PHILLIPS THOMPSON, of the Firm of W. P. Thompson and Co., Patent
Agents, 6, Lord Street, Liverpool, in the County of Lancaster, and 323, High
Holborn, in the County of Middlesex, Civil Engineer.
"IMPROVEMENTS IN AND
APPLICABLE TO STEAM BOILERS, MORE ESPECIALLY OF THE LOCOMOTIVE CLASS."
A communication from abroad by Monsieur George Maréchal, Engineer of Arts &
Manufactures, Paris, in the Republic of France.
The present application has reference to a new furnace applicable to generators
of all kinds, and is designed to permit the employment of inferior fuel, and at the
same time effect economy in expense; also to a disposition of one of the organs of
this furnace so as to constitute a purifier of the water of the boiler. By way of
illustrating the Invention I will describe two modes of carrying it out supplied to
me by the said communicator.
First. The fire chamber of a "locomotive" or other like boiler is divided from
a combustion chamber by a transverse diaphragm made of large fire clay bricks or
blocks. These fire bricks are above the fuel bed, have each one or more perfora-
tions, and surrounding these perforations, between the bricks and partly cut out
of each, are passages opening into the combustion chamber, round the perforations,
the air being brought from a regulated opening below. The gases formed therefore
in the fire chamber by a deep bed of fuel are mixed with the air (already heated
in the diaphragm) as it issues round the gas perforation, forming thus a series of
"Bunsen," or mixed gas combustion jets, in the combustion chamber. Through this
chamber, pendent from the roof of the combustion chamber, hang water tubes
preferably armed with blow off cocks at their extremity, and at the bottom of the
chamber, near the diaphragm or bridge, is a Ivison steam jet.

page_text: The apertures for gas are preferably long horizontal openings opposite the
boiler tubes, one opening in the centre of each fire brick. The bricks are firmly
secured (and kept from shaking) to the sides of the fire box by special metallic
dowells or projecting pieces carried by the supports of the diaphragm.
The second arrangement differs less than the first from the ordinary furnaces in
use, and permits of ordinary thin firing as usually practised in locomotives.
At the end of an ordinary grate is a bridge formed of a vertical metal or fire
brick slab or block, in front a hollow space open to the air below, and a back plate
perforated with a series of holes on Parcel's or Wye Williams' principle. These
holes are small but numerous, and admit the necessary air for the complete conj-
bustion of the gases, the admission being regulated by a damper below as in the
first variety of my Invention.
The space between the bridge and tubes is a combustion chamber filled with
pendent tubes. A perforated fire brick diaphragm separates the combustion
chamber into two parts, and serves with the Ivison steam jet to cause a thorough
mixing of the air and gases. The fire or gas producing chamber in the first variety
is fed from a rectangular cast iron hopper extending the whole breadth of the
furnace, and kept full with free feed into the furnace down the sloping fire hole,
so that so long as the hopper is charged. the furnace remains charged with coal to
the height of the fire hole. The only care required is to avoid entrance of air
when charging the hopper afresh. The pendent tubes are fixed between the fire
box crown stays, and are fastened by conical ferrule in two pieces, screwing and
check nut, or other suitable means. To prevent being bent or disturbed the tubes
are held below by the sheet iron ash pan," or bottom of the chamber covered
with fireclay and pierced with holes, in which the pipes are keyed.
There is the usual damper. Each tube ends in a cock or in a collector pipe
forming the purifying apparatus, the water being shallow above the crown. It is
convenient to adopt a special form of interior tube permitting the water to always
circulate in the tube however low the water is above the crown. This is done by
giving the inner tube lateral egress over the top of the outer tube at two or more
points, so that the currents of the two tubes shall not interfere with each other,
the outer tube being stopped up and the inner one shielded by parallel wings at
these points. The interior tube carries at its inferior extremity three or four little
wings that bind it to a stem which reposes by means of a swelling upon the
bottom cock or mouth of the collector. These tubes are cleaned on the outside by
scraper, inside by blowing off. The crown plate stays are either two plates with
the bolts between, or single plates with the bolts through the centre, and are
arched high above the box to allow freer play for water and steam, or "Belpoire
stays can be used. Field tubes, Monsieur Maréchal considers, have hitherto failed
from faulty construction of crown plate stays, and from not having the herein
described arrangement of internal tube or its equivalent.
"
The pipes for injection of steam are placed in the combustion chamber in such
position that they can preserve a direct action on the flame, the small holes or rose
being fixed so as to project the steam into different planes.
Purifier. In the pendent tubes the circulation is very energetic in the part
directly exposed to the fire, but below the plate suspended matters can subside.
I therefore purify the water by means of terminal blow off cocks screwed to
these tubes; upon the edge of these cocks the stems attached to the vertical tubes
rest. Or instead of cocks I attach to the ends of the tubes collecting tubes or
chambers of sufficient capacity to contain all the deposit of two consecutive
washings or blowings out. These collectors can be fitted to the tubes, so that one
broad collector shall take the deposit from two or more ranges of tubes. Each
⚫ collecting tube is closed at each end by a self-locking stopper, and carries two series
of corresponding tubulures or sockets, one for the pendent tubes, the other for
screw plugs, upon which rest the interior tubes. The joints can be made by ordinary
stuffing boxes with stuffing boxes in which the gland itself becomes a screw; the
tubes can be expanded at these points. Another form of joint is a right and left

page_text: banded nut and screw with springs against the tube to allow of expansion, as will
be set forth more particularly in the final Specification; another plan is a conical
adjustment of an independent piece screwed to the tube, the two being kept
together by a free flange on a ring, in halves, tightened on the independent piece,
and held to the collector by tightening screws.
The main points of this Invention are,―
1st. The arrangement of gas generator and combustion chamber situate in and
forming parts of the same general chamber, the one being applicable to any kind
of fixed generator, portable engine boiler, marine boiler, and the like.
2nd. The particular disposition of the bridge and diaphragms.
3rd. The mounting and entire combination of the pendent tubes and special
arrangement with a view to cleaning.
4th. The construction of crown stays permitting free circulation of water and
the disposing of them lengthwise, raised solely in one part.
5th. The application of pendent tubes to the purifying of water in boilers.
6th. The disposition and arrangement of blow off cocks of collectors designed to
collect deposits.
7th. Modes of joining the tubes.
8th. The charging hopper.
9th. Various arrangements of parts and general combinations set forth.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Phillips Thompson in the Great Seal Patent Office on the
28th July 1880.
"
WILLIAM PHILLIPS THOMPSON, of the Firm of W. P. Thompson and Co., Patent
Agents, 6, Lord Street, Liverpool, in the County of Lancaster, and 323, High
Holborn, in the County of Middlesex, Civil Engineer. IMPROVEMENTS IN AND
APPLICABLE TO STEAM BOILERS, MORE ESPECIALLY OF THE LOCOMOTIVE CLASS."
A communication from abroad by Monsieur George Maréchal, Engineer of Arts and
Manufactures, Paris, in the Republic of France.
This Invention relates to a new arrangement of furnace applicable to many
kinds of generators, and designed to permit the employment of inferior combus-
tibles, at the same time that an important economy in expence is effected; also to
a disposition of one of the members of the apparatus constituting a purifier of the
water of the boiler. Mr. Maréchal has designed two distinct arrangements (repre-
sented in Figures 1 to 5) to attain this end.
In the first the fire is divided by a refractory diaphragm A, Fig. 1, into two
quite distinct compartments, of which one serves as a gas generator, and and the other
as combustion chamber. The gas generator does not differ sensibly from furnaces
of ordinary locomotives, only that the grate is of rather more restricted dimensions,
and it is placed low enough to easily permit the charging of very thick beds of
fuel, or else it is completely closed, and the charging is effected by a rectangular
cast iron hopper in order to prevent the entrance of air. The damper of the ashpit
enables one to regulate the admission of air under the grate.
The combustion chamber is composed of an enclosed space, to the ceiling of which
pendant tubes are fixed in order to (1) augment the direct heating surface; (2), to
break up or more rapidly mix the gaseous currents so that they may be admitted
into the tubular portion of the boiler (the tubes) only when the combustion is
complete; (3), to constitute a water purifier.
The gas generator and the combustion chamber are put into combustion by a
series of openings g, Fig. 1, disposed in horizontal layers (Fig. 2); the diaphragm A
is also between the openings g pierced with long openings a, putting the chamber
of combustion in communication with the external air by means of the space M
closed by the damper R.
The entrances of air alternate in the combustion chamber with the entrances of
gas, and constitute thus a series of fires analogous to the gas fires employed in
metallurgy.
The little tube t of the "Ivison" system, conveniently disposed at the lower
part of the furnace, throws upwards jets of steam which complete the intimate
admixture of the gas and air.
The 2nd disposition or arrangement is a variation or less complete
<< transforma-
tion" than the preceding of the fires ordinarily employed, and which permits the
use of a fire with thin layers of fuel, as in ordinary locomotive furnaces."
At the end of the grate (which does not differ from grates in use) is bridge A¹,
Fig. 4, the hinder part of which is constituted or composed of a wind chest pierced
with a series of holes after the principle of Darcet, or of Wye Williams. These
holes (round or rectangular) are of small diameter, but their number is sufficiently
great to permit the introduction of the air necessary for the complete combustion
of the gases.
This quantity will be varied by the damper R with the nature of
the fuel, and according as the grate is more or less choked.
The free space between the bridge and the tubeplate is a combustion chamber
analogous to that described above, and containing like that one a set of pendulous
tubes,

page_text: .
A diaphragm C, Fig. 4, separates the combustion chamber into two compart-
ments, leaving at the bottom sufficient space for the entrance of the gases. This
refractory earth (fire clay) diaphragm has for its object the breaking up, in com-
bination with the tubes and "Ivison" mixer of the streams of gas, and to render
more intimate the mixture and combination of the combustible gases and air.
DETAILS OF CONSTRUCTION.
The diaphragm A, Fig. 1, is composed of refractory bricks of large size and
special form, as shown in Figs. 1, 2, and 3. The bricks are moulded in such manner
as to present each in its centre a rectangular hole for the entrance of gas, and at
one side (that of the combustion chamber) the edges are cut away in such fashion
as to constitute, when placed in juxtaposition, the entrances for air. The lower
part of this diaphragm contained entirely in the gas generator is of simple refractory
masonry. The whole rests upon two cross pieces ff', Figs. 1 and 2, fixed to the
iron body of the fire box, as is indicated upon Fig. 2.
These cross pieces (Fig. 2) f, f¹, carry each a bracket c, which is fastened at the
same time to the lower part of the fire box, and which follows its contour. In the
roof of this box are two or three dowels, which penetrate into corresponding holes
in the bracket, and maintain it in place. These two brackets, which are embedded
also in the rabbetting of the bricks, are designed to serve as the backbone or frame-
work of the diaphragm so that the diaphragm shall be maintained in place and
not injured by the trepidation of the firebox. To complete the description of the
gas generator, properly so called, it only remains to describe the hopper. This
charging hopper is rectangular and entirely of cast iron. It is the entire breadth
of the fire, and is fixed by the aid of bolts to the two sides of the firebox. The
fuel being charged in a sufficiently thick bed, such as that required in a gas
generator, reaches to the upper part of the hopper. The latter ought then to be
always full, and by this means prevent the entrance of air when it is opened to
charge fuel
In the second arrangement the bridge can be entirely in metal, or entirely in
refractory masonry, maintained in place by an interior frame of iron, and resting
on two cross pieces like those described already, or better yet, as represented in
All that is left to say about the pendent tubes, the purifier, the roof, stays,
etcetera, applies indifferently to both the arrangements of boiler herein described.
The pendent tubes of the combustion chamber are placed between ranges of roof
stays, Figs. 1, 4, 6, and 8.
The tubes are screwed, Figs. 4 and 6, into the roof of the firebox, or adjusted by
means of a conical ring in two pieces, Figs. 1 and 6; Fig. 9 represents this ring
either simply adjusted in holes slightly coned, or else fixed by any other means
ordinarily employed to fix tubes in tubular boilers.
To prevent being bent or shaken the tubes are held at bottom by an iron plate
coated with refractory earth, Figs. 1, 4, 5, 6, pierced with holes exactly corre-
sponding to those in the firebox roof.
To the centre of these holes the tubes are held by the aid of keys, Fig. 6. This
plate, covered with fire clay, forms the bottom of the combustion chamber, a
register R, Figs. 1 and 4, which ought always during the journey to remain well
closed, permits the extraction from the chamber of the ashes or cinders that may
fall into it. Each tube is terminated by a cock, Fig. 1, or ends in a collector, Fig. 4.
It is this lower arrangement of the tube that constitutes the purifier about to be
described shortly.
The depth of water above the roof of the firebox being generally very little, it is
convenient to adopt a special form for the interior tube, and that is why it

page_text: Over the fires of locomotives not only the layer of water is small in depth, but
it is hindered in its circulation by the roof stays, which hug the fire box. To
obviate this inconvenience they should therefore take the form shown by Figs. 1, 2,
and 8. This arrangement could otherwise be replaced by bridge bars on the
'Belpaire" system.
Note. It is because one neglects the study of roof stays as well as of interior
tubes that the application of pendent tubes to the fires of locomotives has never
given other than bad results hitherto. "These attempts were limited to putting
in Field's' tubes, and then occurred what was inevitable with a thin layer of
water, the out going current was very rapid, and the ascensional vein enclosed
between the two roof stays (Fig. 10) could neither spread out nor lose sufficient
speed to prevent its opposing the entrance of water, and in a short time (says Mr.
Maréchal) the tubes were burned."
The Mixing Apparatus.-The tubes t for the injection of steam are placed in the
combustion chamber in such position that they are preserved from the direct attack
of flame. The holes (very small, 4 to 5 millemetres) are originally drilled so as
to eject the steam in different directions.
Purifier. In the pendent tubes the circulation is very energetic in the part
directly exposed to the fire, and limited by the inferior orifice of the interior tube.
On the contrary, in the part of the tube situated below this point there is relative
repose; from this fact it results that calcareous deposits form in the lower part
of the tubes. On the other hand the circulation of the water and the vaporisation
being more energetic in the set of pendent tubes than in all the other parts of the
boiler, nearly all the water will in its turn circulate in the tubes in such manner
that putting together these two facts one sees that the lower part of the tubes
composing the pendent bundle will collect nearly all the calcareous deposits which
form in the boiler.
It is upon this theory that is founded (Mr. Maréchal's) purifier. Two different
dispositions or arrangements are proposed so as to extract these calcareous
deposits. The first, represented at Fig. 6, consists in terminating each vertical
tube by a square part screwed to the end of the tube. This part could be arranged
different ways so long as it is placed and worked easily. In Figure 6 is repre-
sented the one which appears generally preferable for adoption, as its small volume
permits of its easy erection and dismounting.
All these cocks can be opened or closed independently or by groups, a row or
half a row at a time. For this purpose it will suffice to attach to a coupling bar
all the handles of those which it is desirable to manœuvre at one time.
Figure 1 shows this arrangement.
The second arrangement consists in uniting the lower extremities of a certain

page_text: number of tubes in a single collector of sufficient volume to collect all the scale
which can form between two successive blows.
The collector can be disposed or arranged for two or three ranges of tubes
(Figures 12, 13, and 14), at will. In the case where there are seven ranges of
tubes, Figure 1, one can put, as indicated in Figure 12, 13, 14, two collectors for
two ranges each, and one for three.
Each collector is composed of a horizontal cylinder closed at the two ends by a
self closing cap; it carries two series of corresponding tubulures, one of the series
receives the lower extremities of the pendent tubes, and the other the screwed caps
upon which repose the interior tubes, and which permit their extraction (Figs. 12,
13, and 14).
The joint between the tubes and the collector can be made in many different
manners, among the rest the following
In
Figures 12, 13, and 14 show a joint made with an ordinary stuffing box;
Figure 16 shows a stuffing box, of which the cap is formed with a screw.
these two cases the tubes can expand freely, and the collector is fixed immoveably.
Figure 14 shows a joint made by the aid of a right and left handed nut. In
this case, the tubes being bound to the collector in a rigid manner, the latter is
mounted upon springs which allow it a light vertical movement so as to obey the
expanding tubes in their downward impulse and subsequent contraction.
In Fig. 17 is shown another mode of fixed junction. A piece screwed to the
extremity of the tube is terminated by a conical adjutage, which enters into the
tubulure of the collector. This joint is maintained by the aid of a loose retaining
piece resting upon the upper part of the swelling of the adjutage by the aid of a
ring in two pieces. In this case, as in the preceding, the collector is capable of
moving vertically so as to allow for expansion.
Figures 4 and 5 show a general arrangement of the collectors. They are sus-
pended in the same manner as the boiler. If there be two or three ranges of tubes
one always puts a single collector for the lot, and in this case not being hindered
by neighbouring collectors one can make the collector of larger dimensions, and
thus it will last longer without the necessity of blowing off.
In conclusion, one sees that by this process the fire ought to give above those
in actual usè an important economical result.
1st. A mode of heating which permits the employment of a very small excess of
air for the combustion.
"
2nd. An intimate mixture of gas and consequent complete combustion, in spite
of the feeble excess of air, through the use of pendent tubes and "Ivison
mixer.
3rd. A direct augmentation of heat by adding the pendent tubes.
4th. Less elevated temperature of gases since their circulation is slower.
5th. Greater conductivity of the surfaces in contact with the hot gases owing
to the purifying of the water, which no longer leaves scale adhering to the
surfaces.
APPLICATIONS.
The fire already described is applicable more particularly to boilers with internal
flues.
In many cases some only of the parts described can be applied to other generators,
this is particularly the case with the pendent tubes and purifier.
Fig. 18 shows a partial application of this system to a boiler of a locomotive, of
which one did not wish to entirely transform the firebox. The grate is limited by
a small refractory wall in front of the pendent tubes. The fire box is less than
that already described, and further the tubes only occupy a small part of it, it
is, therefore, not necessary to arrange the roof stays transversely, as previously
described, they can be placed longitudinally, modified in form, as indicated in
Fig. 18, by raising them up above the tubes in such manner as to permit the circu-
lation of water; Fig. 19 indicates also a partial application to the furnace of a

page_text: portable engine. The raised roof stays not having such large span can be placed
longitudinally. A roof stay can also be made analogous to that represented in
Figure 18.
In these two last applications the tubes terminate in cocks; it is evident,
however, that collectors could be used in place of the said cocks.
Having now described the Invention exactly as communicated to me by my
foreign correspondent, I wish it to be understood that what I claim to be new, and
desire to protect under the herein before in part recited Letters Patent is,―
1st. The arrangement of gas generator and a combustion chamber, compart-
ments of one chamber, the whole of which is utilized as direct heating surface,
whether applied to locomotives or to other boilers, substantially as described.
2nd. The special arrangements of bridges and diaphragms, substantially as and
for the purposes described.
3rd. The construction and entire combination of pendent tubes herein described,
especially as relates to cleaning out.
4th. The special construction of roof stays for permitting a free circulation of
water, as herein described.
5th. The longitudinal arrangement of roof stays with a part raised up or cut
away so as to leave more room over the tubes.
6th. The application of pendent tubes to the purification of water in steam
boilers, substantially as described.
7th. The special arrangement of blow off cocks herein described.
8th. The arrangement of collectors destined to collect deposits, herein
described.
9th. The various arrangements shown in the Drawings for joining the pipes to
the collectors.
10th. The arrangement for converting or the partial application to a locomotive
or portable engine, as set forth in Fig. 18 and 19, or equivalent design for other
styles of boilers.
11th. The general arrangement and construction of apparatus with the various
details specified as new in the Specification, and set forth in the Drawings, each
part when in combination with the others, substantially as set forth.
In witness whereof, I, the said William Phillips Thompson, have hereunto set
my hand and seal, this Twenty sixth day of July, in the year of our Lord
1880.
W. P. THOMPSON. (L.S.)