Year: 1897

page_text: (A communication by E. H. RIEKEN, of Box 1719, New Orleans, in the County of
Orleans, and State of Louisiana, United States of America.)
I, WILLIAM SCRIMGEOUR, of 34, Ireton Street, Liverpool, in the County of
Lancaster, Engineer, do hereby declare the nature of this invention to be as
follows:-
This invention relates to steam boilers which consist of nests of tubes in con-
nection with cylindrical drums containing steam and water, and similar drums for
collecting the impurities contained in the feed water, tubes containing water
being exposed at their outer surfaces to the hot gases from the furnace; the
object of the invention is to construct a boiler having its tubes so arranged as to
expose them to the furnace heat in a most efficacious position, as well as for the
circulation of water and steam within; also making the tubes more easily
accessible for purposes of cleaning and repair, with a limited number of removable
handhole plates and joints; and to construct the boiler in general so as to divide
it into sections, a deficiency in any one of which not involving any great danger
from destructive explosions; also to construct a furnace to be used in connection
with the boiler and depending for its efficiency principally upon the proportions
and general design that the peculiar construction of the boiler admits, such as
will promote the more economical consumption of fuel; thus increasing the
efficiency of the construction as a whole.
The design and construction of the boiler is as follows:-
The water tubes constitute the greater portion of the boiler and are so formed
as to enter headers in a straight row at one end, and to enter lower drums at the
other end in a staggered or zigzag order, the lower ends being curved in order to
enter the drums in radial lines converging toward the axes of the drums. A
relatively short distance below their upper ends the tubes are offset or crimped,
part of the tubes being offset to one side and part of the tubes being offset to the
other side, this offsetting only being sufficient to cause the alternate rows of
tubes to assume the staggered or zigzag order afore-mentioned, below the place
where they cross the rows of tubes coming from the opposite side of the boiler.
This offset in each tube only amounts to that much as will not prevent the intro-
duction of a perfectly straight rod into any of the tubes for purposes of cleaning,
only being limited by the curve at the lower end of the tubes, this curved portion
being accessible from the interior of the lower drums.
Four separate muddrums may be used in each set on sides of boiler, but the
number of drums and the diameter thereof is immaterial, provided they are sufficiently

page_text: large to admit the necessary tools through the holes in the outer end, and provide
sufficient working room for their manipulation in attaching or removing boiler
tubes. When boiler tubes of small diameter are employed the drums will each
receive a greater number of tubes than if the diameter of tubes is large. The
object is to allow access to the tubes without the necessity of handholes opposite
each tube in the lower drums.
The tubes may be in successive straight rows as they are arranged above the
crossing with the tubes coming from the opposite side, also the spaces for he
passage of gases from the furnace, or the tubes may be in straight rows at the
place where they cross each other, spaces being provided for the passage of gases
from the furnace.
The tubes may be in staggered or zigzag.rows, every successive row being made
to assume such order below the place where the opposite rows cross them.
Every successive row of tubes on each side is connected with the upper steam
and water drum by means of short curved tubes fixed at one end into the headers
and at the other end into the drum and being accessible from the inside of said drun
also from the end of header by removing the handhole cover in one end of the
header.
The lower drums are placed in rows on each side of the boiler for the reception
of the lower tube ends and are connected with each other by short tubes.
manhole on the outer ends of these drums gives access to their interior for the
purpose of expanding the tubes and cleaning their lower ends. The end drums
on each side are connected with the upper drums by the pipes or downtakes, these
being of sufficient diameter to insure perfect circulation of the water and steam
within the boiler. The upper drum is made to project sufficiently over the casing
ends so as to allow the downtakes to enter it radially. Openings are provided in
the drums or in the downtakes for the injection of the feed water to the boiler.
The downtakes are passed through the smoke flues at one end of casing, or should
it be necessary to provide a smoke-stack and flues at both ends of the casing the
downtakes at the other end will be passed through the flues likewise.
The downtakes thus absorb considerable heat from the waste gases passing to
the stacks. As the inner ends of the lower drums are inclined downwards, the
solid impurities contained in the feed water will naturally deposit at that place.
The pipe connected with the lower ends of the drum serves to withdraw and
expel the impurities mentioned above. The entire boiler when in operation is
kept filled to the centre of the upper drum. The boiler exclusive of casing is sup-
ported on chairs, having their upper seats concaved for the reception of the drums
and their lower seats curved convex so as to admit of their rocking, as each nest
of tubes expands or contracts unequally; the anchor pins loosely entering ar
opening in the lower seats serving to keep the chairs from shifting their position.
The header consists of a pipe or box, the upper and lower sides being flattened
for the purpose of more effectively expanding the tubes therein. The handhole
seat consists of a circular ring of metal having one of its faces perfectly flat and
smooth and is fixed to the inside of the tube by a short piece of tube of larger
diameter than the boiler tubes, the tube being expanded into both ring and
header, the cover being held against the finished face of ring by the clamp and
bolt fixed to the cover. As the handhole plates and seats are of larger diameter
than the holes in the header, the handhole in the end of the header is made of
larger diameter and elliptical in form so as to admit of its own cover being held
on the inside of header. The end handhole seat is also fixed to the header
by a short tube on end thereof being expanded into the header and the seat
being expanded or driven into the end of the tube, the seat being of circular
form with a shoulder forced against the end of the tube, both having the same
outside diameter, the hole in the scat being of elliptical form as already described.
The tube holes and handholes in the header are made of larger diameter than
the outside of the boiler tubes, the difference in diameter between the tube holes
and tubes being filled by a ferrule encircling the upper tube ends.

page_text: The tube holes and handholes in header are relatively placed in a noncentric
position, their centres being shifted to such an extent so that the horizontal
distance between the diagonally opposite edges of the tube and handholes respec-
tively will be equal to the external diameter of one of the boiler tubes. The
straight portion of tube always maintains a position at right angles to the axis
of header, whether the straight or the offset portion of tube is being drawn through
the holes in header, this arrangement also facilitating the passage of the curved
ends of the tubes.
The furnace consists essentially of the grate; the refractory lining at the inner
ends of the drums; the refractory lining resting on the outside of the tubes, and
extending from one end of the furnace to the other end, and tapering' upwards
to a contracted aperture which is partially filled by the boiler tubes. On each side
of the refractory lining and at some distance from it is placed the refractory
lining attached to the metal casing; the space between them serving as a jacket,
also constituting the flues for the discharge of the waste gases to the stack. The
ends of the casing forming the ends of the furnace and likewise provided with a
refractory lining. The upper part of the casing is formed so as to enclose the
upper tube ends and headers and is then brought up against the bottom of the
upper drum. The doors give access to the upper tube ends and headers for the
purposes of cleaning and replacing of tubes. The construction of this furnace
permits the radiation of heat to the boiler tubes and a better and more thorough
combustion of fuel, and a better absorption of heat than is practicable where the
convection of heat from gases circulating across or along the tubes is relied upon.
The latter principle permits of the speedy escape of only partially consumed and
utilized gases. In the present construction the gases are retarded and being con-
tained in a heated chamber are more effectively ignited and consumed, this
resulting in a more intense furnace heat. As the combustion chamber is almost
entirely formed by the boiler tubes there is no space for the waste of the furnace
heat, the sides of the furnace tapering upwards and being sufficiently wide at
the bottom to provide sufficient grate area, and sufficiently wide at the top to
provide proper Hue area for the discharge of the waste furnace gases, it will be
apparent that the consequence will be a more thorough utilisation of the caloric
potential of the fuel supplied to the furnace than is possible without this con-
struction.
A feature of the invention is the tubes arranged in straight rows, the rows of
tubes inclined towards the perpendicular plane passing through the centre of the
boiler or steam drum, the upper end of each row of tubes being connected into
an independent manifold header, having connection with steam drum by a tube
or tubes and the lower ends of the tubes connected into suitable mud drums.
My correspondent has described the above way of carrying the invention into
effect but it must be understood that alterations may be made without departing
from the nature of the invention. Thus for example longitudinal and lateral
arrangements of mud drums may be introduced which are only modifications of
one and the same element. The header construction with the cross tubes may
form one construction of boiler, while the direct, tube and steam drum connection
may form a construction separately from the other, and both arrangements are
intended to be covered in this application.

page_text: (A communication by E. H. RIEKEN, of Box 1719, New Orleans, in the County of
Orleans, and State of Louisiana, United States of America.)
I, WILLIAM SCRIMGEOUR, of 34, Ireton Street, Liverpool, in the County of
Lancaster, Engineer, 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:-
-
This invention relates to steam boilers which consist of nests of tubes in con-
nection with cylindrical drums containing steam and water, and similar drums for
collecting the impurities contained in the feed water, tubes containing water
being exposed at their outer surfaces to the hot gases from the furnace. The
object of the invention is to construct a boiler having its tubes so arranged as to
expose them to the furnace heat in a most efficacious position, as well as for the
circulation of water and steam within; also making the tubes more easily
accessible for purposes of cleaning and repair, with a limited number of removable
handhole plates and joints; and to construct the boiler in general so as to divide
it into sections, a deficiency in any one of which not involving any great danger
from destructive explosions; also to construct a furnace to be used in connection
with the boiler and depending for its efficiency principally upon the proportions
and general design that the peculiar construction of the boiler admits, such as
will promote the more economical consumption of fuel; thus increasing the
efficiency of the construction as a whole.
These objects are attained by the construction shown in the accompanying draw-
ings, in which ;
Figure 1 is an end view of the boiler and furnace, one of the furnace ends
being removed.
Figure 2 is a section through the arrangement of the boiler tubes on the line E.
Figure 3 is a section on the line F.
Figure 4 is a section on the line H.
Figure 5 is an elevation of the boiler and furnace casing with one of the sides
of the casing removed.
Figure 6 is an end view of the furnace and boiler casing.
Figure 7 is an elevation of the part shown in Figure 6.
Figure 8 is a section through the form of header which is employed.
Figure 9 is a longitudinal section through the same.
Figure 10 is a view of the outside of header.
Figure 11 is a view of the handhole end, and
Figure 12 a view of the tube hole end.
Figure 13 is an end view of a row of tubes connected into the header.
Figure 14 is an elevation of same.
Figure 15 is an end view of a boiler with two steam drums, and
Figure 16 a side elevation with one side of casing removed.
Similar letters refer to similar parts throughout the different views.
The design and construction of the boiler are as follows:-
The water tubes a and b constitute the greater portion of the boiler, and
are so formed as to enter the headers A (which are respectively situated on
each side of centre line of boiler) in a straight row at one end, and to enter
the mud and water drums C at the other end in a
or zig-zag order, the lower ends being curved in order to enter the drums C
staggered

page_text: in
radial lines converging toward the axes thereof. A relatively
short distance below their upper ends the tubes are offset or crimped (Figures 5
and 13) part of the tubes being offset to one side and part of the tubes being
offset to the other side, this offsetting only being sufficient to cause the alternate
rows of tubes to assume the staggered or zigzag order aforementioned, below the
place where they cross the rows of tubes coming from the opposite side of the
boiler. This offset in each tube does not amount to so much as will prevent the
introduction of a perfectly straight rod into any of the tubes for purposes of
cleaning, the cleaning being only limited by the curve at the lower end of the
tubes, but this curved portion is accessible from the interior of the lower drums C,
so that the curve can be cleaned from that end. The drums C are arranged in sets
in each side of the grate and their longitudinal axes are parallel with the axes
of the headers, which latter are at right angles to centre line of boiler. The
successive rows of tubes on each side of the boiler form collectively two clusters,
both clusters being inclined and pass from opposite sides through the perpen-
dicular central plane of the boiler, in such manner that the two clusters of tubes
cross each other.
The drawing shows four separate mud drums, in each set on sides of boiler,
but the number of drums and the diameter thereof is immaterial, provided they
are sufficiently large to admit the necessary tools through the holes in the outer
end, and provide sufficient working room for their manipulation in attaching
or removing boiler tubes. When boiler tubes of small diameter are employed the
drums will each receive a greater number of tubes than if the diameter of tubes
is large. The object is to allow access to the tubes without the necessity of hand-
holes opposite each tube in the lower drums.
Figure 2 shows the tubes in successive straight rows as they are arranged above
the crossing with the tubes coming from the opposite side, also the spaces for
the passage of gases from the furnace.
Figure 3 shows the tubes in straight rows at the place where they cross each
other, also the spaces for the passage of gases from the furnace.
Figure 4 shows the tubes in staggered or zigzag rows, which order every succes-
sive row is made to assume below the place where the opposite rows cross them,
showing the spaces for the passage and circulation of gases from the furnace.
Every successive row of tubes on each side is connected with the upper steam
and water drum e by means of short curved tubes i fixed at one end into the
headers and at the other end into the drum e, and being accessible from the
inside of said drum also from the end of header by removing the handhole cover j
Figs. 9 and 14 in one end of the header.
The lower drums C are placed in rows on each side of the grate for the reception
of the lower tube ends and are connected with each other by the short tubes. A
manhole C on the outer ends of these drums gives access to their interior for the
purpose of expanding the tubes and cleaning their lower ends. The drums C
on each side are connected with the upper drums e by the pipes or downtakes f,
these being of sufficient diameter to insure perfect circulation of the water and
steam within the boiler. The upper drum e is made to project sufficiently over
he casing ends so as to allow the downtakes f to enter it radially. Openings El
are provided in the drums e, or in the downtakes f for the injection of the
eed water to the boiler. The downtakes f are passed through the smoke flues
t one end of casing, or should it be necessary to provide a smoke stack and flues
t both ends of the casing the downtakes at the other end will be passed through
he flues likewise. The downtakes thus absorb considerable heat from the waste
rases passing to the stacks. As the lower drums C slope downwards, the solid
mpurities contained in the feed water will naturally deposit at that place. The
ipe h which is connected with the lower ends of the drums serves to withdraw
nd expel the impurities mentioned above. The entire boiler when in operation
kept filled to the centre of the upper drum e. The boiler exclusive of casing a
supported on the chairs k, Figure 1, having their upper seats concaved for the

page_text: 11
."
reception of the drums C, and their lower seats curved convex so as to admit
of their rocking, as each cluster of tubes expands or contracts unequally; the
anchor pins cloosely entering an opening in the lower seats serving to keep the
chairs from shifting their position. K are bases on which the chairs rest. The
header A illustrated by Figures 8, 9, 10, 11 and 12 consists of a pipe or box of
the cross section shown in Figure 8, the upper and lower sides being flattened
for the purpose of more effectively expanding the tubes therein. The seats, of
the hand-holes A' consist of a circular ring of metal, having one of its faces perfectly
flat and smooth, and are fixed to the inside of the header A by short pieces of
tube n of larger diameter than the boiler tubes, the tube being expanded into both
ring and hole A' in header, and the cover S₁ being held against the finished
face of ring by the clamps and bolt S fixed to the cover St. As the hand-
hole plates and seats are of larger diameter than the holes in the header, the hand-
hole T in the end of the header is made of larger diameter and elliptical in form,
so as to admit of the cover S₁ being passed' through it, and also of its own cover
being passed through and held on the inside of the plate or head A³..
The tube holes a and handholes "A' in the header A are made of larger diameter
than the outside of the boiler tubes, the difference in diameter between the tube
holes and tubes being filled by a ferrule a² encircling the upper ends of tubes.
'P
The tubeholes and handholes A¹ in header are relatively placed in a non-
centric position, as shown in Figure 10, their centres being shifted to such an
extent so that the horizontal distance between' the diagonally opposite, edges of
the tube and handholes respectively, will be equal to the external diameter of one
of the boiler tubes. The object of this arrangement is clearly illustrated by the
tubes in dotted lines in Figure 9, the straight portion of tube always maintaining
a position at right angles to the axis of header, whether the straight or the offset
portion of tube being drawn through the holes in header, this arrangement also
facilitating the passage of the curved ends of the tubes. A is the head in the
opposite end of header to head A³. It is provided with holes for receiving the
tubes i.
The furnace consists essentially of the grate u; the refractory lining m at the
inner ends of the drums C; the refractory lining vv resting on the outside of
the tubes a and b and extending from one end of the furnace to the other end, and
tapering upwards to a contracted aperture 1) which is partially filled by the boiler
tubes. On each side of the refractory lining vv and at some distance from it is
placed the refractory lining w w attached to the metal casing a; the space between
them serving as a jacket X, also constituting the flues for the discharge of the
waste gases to the stack. The ends of the casing a also form the ends of the
furnace and are likewise provided with a refractory lining as shown in Figure 5.
The upper part of the casing is formed so as to enclose the upper tube ends and
headers and is then brought up against the bottom of the upper drum e. The
doors y give access to the upper tube ends and headers for the purposes of cleaning
and replacing of tubes. Y is the smoke stack. The construction of this furnace
permits the radiation of heat to the boiler tubes and a better and more thorough
combustion of fuel, and a better absorption of heat than is practicable where the
convection of heat from gases circulating across or along the tubes is relied upon.
The latter principle permits of the speedy escape of only partially consumed and
utilised gases. In the present construction the gases are retarded and being
contained in a heated chamber are more effectively ignited and consumed, this
resulting in a more intense furnace heat. As the combustion chamber is almost
entirely formed by the boiler tubes there is no space for the waste of the furnace
heat, the sides of the furnace tapering upwards and being sufficiently wide at
the bottom to provide sufficient grate area, and sufficiently wide at the top to
provide proper flue area for the discharge of the waste furnace gases, it will be
apparent that the consequence will be a more thorough utilisation of the caloric
potential of the fuel supplied to the furnace than is possible without this con-
struction.

page_text: _A feature of the invention is the tubes arranged in straight rows, the rows of
tubes inclined towards the perpendicular plane passing through the centre of the
boiler or steam drum, the upper end of each row of tubes being connected into
an independent manifold header, having connection with steam drum by a tube or
tubes and, the lower ends, of the tubes connected into suitable mud drums.
My correspondent has described the above way of carrying the invention into
effect, but it must be understood that alterations may be made without departing
from the nature of the invention. Thus for example longitudinal and lateral
arrangements of mud drums may be introduced which are only modifications of
one and, the same element. The header construction with the cross tubes may
form one construction of boiler, while the direct tube and steam drum connection
may form a construction separately from the other, and both arrangements are
covered in this application.
The latter arrangement is shown in Figures 15 and 16 in which the tubes a b
are arranged in straight rows, and the rows of tubes alternately cross each other
from opposite sides of boiler. At the lower ends, the tubes are connected with
the longitudinal mud drums C placed at each side of grate u, said lower drums
being supported on the chairs Fig. 1 as before described. The upper ends of
tubes are connected with the longitudinal steam and water drums e of which a two
drum arrangement is shown in Figure 15, the object of the double drums being
to supply the greater steam and water space required in boilers designed for heavy
duty, and consequently more rapid evaporation of the water within.
The down take pipes f are of relatively large diameter and form the return
connection between the upper and lower drums.
The refractory side linings and end linings together with the grate u con-
stitute the furnace, the whole being enclosed by the casing a, passages being
formed at the sides of boiler between the casing sides and the linings for the
discharge of the waste gases to the breeching and stack Y, the breeching being
attached at end of casing and opposite the openings provided in end of casing to
permit the escape of gases to stack.
The interior of the steam drums e are provided with curved shields m¹, these
being placed at suitable distances from the interior surface of drums, the edges of
each shield projecting slightly above the water level in drum, the shield extending
a short distance beyond the end rows of tubes at each end of boiler; a flange
being formed at each end of shield, the edge. of flanges being bent squarely over
to attach to interior of drum, thus insuring the complete separation of the generating
water (that is the water and steam blowing from the tubes) from the water stored
in the drums and which replenish the boiler through the downtake pipes f. The
deflectors are placed over the open spaces at each side of drum, their function
being to precipitate the entrained water downwards which emerges through the
openings between drum and shield, while the steam is allowed to rise into the
steam space of drum.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, as communicated to me
by my foreign correspondent, I declare that what I claim is:-
1. A water tube steam boiler in which the water tubes are arranged in rows,
but inclined towards and crossing a perpendicular plane passing through the
centre of the boiler, in such a manner that the outer surfaces are exposed to the
hot gases from the furnace in the most efficacious position, the upper end of each
row of tubes being connected with an independent header or manifold having
connection with steam druin or drums, or with the steam drums direct, and the
lower ends of the tubes with drums for collecting the impurities contained in the
feed water, substantially as described.
2. The improvement in water tube boilers, which consists in arranging the
tubes in rows so as to form collectively two clusters, the clusters inclined and
crossing each other from opposite sides, and in connecting each cluster of tubes

page_text: with headers at the upper end having connection with the steam and water drum,
or direct with the said drum, and at the lower end with mud drums arranged in
sets at each side
the grate, the tubes entering these drums radially, substantially
as described.
3. The combination in a steam boiler, of water tubes arranged in rows so as to
form collectively two clusters inclined towards and crossing each other from
opposite sides of the grate, and passing through the perpendicular plane of the
boiler centre, each row of these tubes following a straight line at and above the
place of their crossing, and below the crossing being offset or crimped alternately
to either side of the perpendicular plane, in such a manner as to assume a staggered
or zig zag order in contradistinction to the straight row arrangement at and above
crossing, substantially as described.
4. In a water tube boiler of the kind described (a) arranging the headers to
which the upper ends of the water tubes are connected in such a manner that
their axes extend at right angles to the centre line of steam drum and boiler,
the headers being respectively situated at each side of boiler, and (b) arranging
the mud and water drums to which the lower ends of the tubes are connected with
their longitudinal axes parallel to the axes of headers at upper ends of tubes,
these drums being arranged in sets at each side of the grate, and having independent
connection with each other by pipes, and with the steam drum with which the
headers communicate, by suitable downtake pipes, substantially as described.
5. In a water tube boiler, the use of headers or manifolds, each consisting of a
tube flattened at upper and lower sides and provided with circular holes, one set
of which on one side hold the ends of the water tubes which are fixed therein,
and the other set of holes on the other side which give access to and allow of
the passage through headers of said tubes provided with removable covers, while
the ends of the headers are provided with heads to one of which is secured the
connecting tube or tubes to steam drum, and the other head containing a hand-
hole with removable cover, substantially as described.
6. In a water tube boiler, providing one set of the holes in the headers or drums
with removable seats for hand hole covers, said seats consisting of rings mounted
on the inner surface of headers by short tubes or sleeves, said tubes being expanded
into the holes of the headers and into the rings, and the rings being formed with
a seat on one side to receive the hand hole cover, substantially as described.
7. In a water tube boiler in which the water tubes are connected at their lower
ends with mud drums located on the opposite side of the boiler to their upper
connection with headers, mounting the said drums on rocking chairs & having rests
at top concaved to receive the mud drums and made convex at bottom in such a
manner as to admit of their rocking as each cluster of tubes expands or contracts,
said rocking chairs resting on bases and held from shifting therefrom by pins, bolts,
shoulders or the like, substantially as described.
8. In a water tube boiler, the combination of water tubes which are connected
at their lower ends with mud drums located on the opposite side of the boiler to
their upper connection with headers or steam drums, and a furnace and casing
consisting of a grate located intermediate between the mud drums, and provided
with suitable refractory shields to protect the drums, an external box or casing of
suitable metal, designed to form a smoke passage or flue and having connection
with a smoke stack, refractory side walls converging upwards to a contracted
aperture which is partly filled by the water tubes, and a second refractory
lining outside the other one, the space between them serving as a jacket which
constitute flues for the passage of the waste gases to the stack, substantially as
described.
9. In a water tube boiler, having a steam and water drum e in which the upper
ends of the water tubes are fixed, the combination therewith of the curved shields m
flanged at both ends and placed at suitable distances from the interior surface of
the drums, immediately over the orifices of the tubes to insure the separation of
the water and steam blowing from the tubes, from the water stored in the drums

page_text: to replenish the boiler, and deflector plates 9 placed over the open spaces at each
side of drum, their function being to precipitate the entrained water downwards
which emerges through the openings between the drum and shield, while the
steam is allowed to rise into the steam space, substantially as described.
10. In a water tube boiler, arranging the tubes in straight rows inclined towards
the perpendicular from both sides, and passing through the central vertical plane
of the boiler, the lower ends of tubes having connection with longitudinal mud
drums and the upper ends having connection with suitable steam drum or set of
drums, in combination with a furnace and casing consisting essentially of an outer
metallic casing, converging refractory side walls, a stack and breaching and a
suitable grate located intermediate between the longitudinal mud drums, substan-
tially as described.
11. The general combined arrangement and construction of parts forming the
improved water tube boilers, substantially as herein set forth.
12. Constructing and arranging the combustion chamber so that it shall be
wide at bottom to provide ample grate area, but with sides tapering upwards to a
contracted aperture which is partly filled by the boiler tubes, whereby the gases
are retarded, and being contained in the heated chamber are more effectively
ignited and consumed, and a better absorption of heat secured, substantially as
set forth.
91 of December 1897