Improvements in Water-tube Boilers
Year: 1894

page_text: Date of Application, 4th Oct., 1894
Complete Specification Left, 4th July 1895-Accepted, 10th Aug. 1:95
Improvements in Water-tube Boilers
I, JOHN ISAAC THORNYCROFT, a member of the Firm of John I. Thornycroft
& Co, Steam Yacht and Launch Builders, of Church Wharf, Chiswick, in the
County of Middlesex, do hereby declare the nature of this invention to be ns
follows:-
This invention has reference to an improved construction and arrangement of
water-tube boiler, specially designed for use in navigable vessels of small size, such
as launches and pinnaces.
The
A steam boiler according to this invention comprises a combined steam collector
and separator, hereinafter called a steam drum, aud a water vessel, arranged one
above the other at one side of and within a casing, and connected by a main
group of bent tubes that serve to divide the interior of the casing, practically
in a diagonal mauner, into two longitudinal chambers, the lower of which serves
as a fire-box, and in the upper of which the steam drum is located. The down-
take tube or tubes connecting the bottom of the steam drum with the water
vessel is or are, or may be, also arranged within the said upper chamber
tubes composing the main group of tubes form one side and the roof of the
fire-box and are so bent and disposed that some of them form two close walls of
a flue, within which the remaining tubes are arranged, this flue communicating at
its lower part with the fire-box through openings between the lower ends of the
tubes forming the inner wall of such box, and at its upper end, through similar
openings between the upper ends of the tubes, with the uptake, either directly
through the portion of the upper chamber that is above the steam drum, or
indirectly through the portion of the said chamber that is below the said drum,
or through both of these portions of the said chamber.
The other or outer side of the fire box is formed by bent tubes arranged
close together and in a row along their vertical portions and connected at their
upper and lower ends with the steam drum and water vessel respectively, their
upper ends being so disposed as to extend over the upper ends of the bent tubes
in the main group, and to leave openings between them through which the hot
gases and products of combustion can pass direct to the uptake.
These tubes may, at their lower euds, be advantageously bent inward towards
the water vessel to which they are connected, so as to form hollow grate bars,
through which water will circulate, when the boiler is in action, the portions of the
tubes forming the fire bars being made of smaller diameter than the remaining
portions, in order to form air passages between them. This construction of one
side of a file box and fire grate by a row of tubes may advantageously be used in
constructions of water tube boilers other than that herein before described.
obviate damage of the hollow giate bars by direct contact with the fuel and by the
tools used to clean the fire, the said hollow grate bars may be protected by
removable bars of approximately T shape in cross section and having preferably
convex upper surface.
To
To control the duection of the escaping hot gases and products of combustion,
a flap or damper is or may be arranged above the upper ends of the bent tubes
in such a manner that in one position it will permit the hot gases and products
of combustion to pass directly to the uptake and when in another position will

page_text: cause the said hot gases and products of combustion to pass around the lower
side of the steam drum and thence to the uptake.
To simplify and cheapen the construction of the steam drum and water vessel,
and to permit of access being readily gained to their interiors, the end covers of
each of them are or may be secured in place by one or more bolts passing through
the steam drum or water vessel, as the case may be, and the end covers, and
provided on its or their outer ends with holding up nuts
To separate the steam from the water projected into the steam drum from the
upper ends of the bent tubes, a baffle or buffles 15 or are provided. A convenient
construction of baffle for this purpose according to this invention consists of a
uumber of bars or strips arranged parallel with each other, and at a distance apart
in two or more rows, the bars or strips in one row being opposite the spaces
between the bars or stips in the adjacent row The bars are connected together
at then ends by suitable carriers or supports, and are preferably grooved in the
direction of then length so as to be of angular, senu-cucular or equivalent form in
cross-section.
Tandh
1
1004
1, JOHN ISAAC THORNYOROFI, a member of the Firm of John 1. Thornycroft
& Co. Steam Yacht and Launch Builders, of Church Wharf, Chiswick, in the
County of Middlesex, 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 has reference to an improved construction and arrangement of
water-tube boiler, specially designed for use in navigable vessels of small size, such
as launches and pinnaces as I will now proceed to explain by the aid of the
accompanying illustrative diawings in which,
Fig. is a longitudinal vertical section, and Fig. 2 a cross section, showing my
improved boiler
Figs. 3 and 4 are respectively a side elevation and horizontal section showing au
improved construction of baffle for use in such boiler
Fig. 5 shows partly in cross section and partly in end elevation, a modified
coustiuction of the boiler.
A steam boiler according to this invention comprises an upper combined steam
collector and separator 1 (hereinafter called a steam dium), and a lower water
vessel 2 these being arranged longitudinally one above the other at one side of and
within a casing 3 so as to extend from front to back of the boiler. They are
connected by a main longitudinal group of bent tubes 4 that serve to divide the
interior of the casing, practically in a diagonal manner, into two longitudinal
chambers 5 and 6, the lower of which, uz. 5, serves as a fire-box, and in the upper
of which, ez. 6, the steam diam 1 is located. The downtake tube 7, or tubes,
connecting the bottom of the steam drum with the water vessel, 18 or are, or may
be also arranged within the said upper chamber 6, as in the example shown,
though it or they may, if desired, be external to the boiler casing 3. When
arinnged in the said upper chamber, as shown, several of such tubes may be used
The tubes 4 composing the main longitudinal group of tubes, form one side and the
roof of the fine-box 5, and are so bent and disposed, in a manner now well

page_text: understood in connection with water tube boilers of the Thornycroft type and is
shown in the drawings, that some of them form two close walls 4ª, 4 of a flue 4º
within which the remaining tubes are arranged, this flue communicating at its
lower part with the fire-box though openings 44 between the lower ends of the
tubes forming the inner wall 4 of such box, and at its upper end, through similar
openings 4, 4' between the upper ends of the tubes forming the walls 4", 4, with
the uptake 8, either duectly through the portion of the upper chamber 6 that is
above the steam drum 1, by passing through the openings 4º, or indirectly through
the portion of the said chamber 6 that is below the said dium, by passing through
the opening 4', or through both of these portions of the said chamber by passing
though both sets of openings 4° and 4' simultaneously The openings formed
by the bending of the lower ends of the tubes constituting the wall 4b, are closed
by refractory material such as fireclay, to prevent escape of flame and hot gases at
these points
The other side of the fire box 5 is formed by bent tubes 9 that are ranged
close together and in a row along their vertical portions, and are connected at
the upper and lower ends with the steam drum 1 and water vessel 2 respectively,
then upper ends being so bent and disposed, as shown, as to extend over the upper
ends of the bent tubes 4, and so as to leave openings 9 betweon then through
which the hot gases and products of combustion, "after passing through the
openings 4 between the upper ends of the tubes 4 forming the wall 4", can pass
direct to the uptake 8. The upper ends of the tubes 4 and 9 are shown connected
to the upper side of the steam dium, as I consider this the most advantageous
arrangement, but I do not limit myself to such an arrangement, as they may be
connected to any other desued part of the steam diam, in which case the position
of the said drum can also be changed if desned. The tubes 9 may, at their lower
ends, be advantageously bent inward, as shown, towards the water vessel 2 to
which they are connected, so as to form hollow giate-bars 9 through which water
will enculate when the boiler is in netion, the portions of the said tubes forming
the said ginte-bais, being made of smallet diameter than the remaining portions,
in order to form air passages between them, as shown in Fig. 1. This construction
of one side of a fire box and fe gate by a low of tubes may advantageously
be used in constructions of water tube boilers other than that her embefore
described
10 is a blast pipe extending through the upper chamber 6 past the steam dium
and terminating at the base of the uptake 8. 11 is refractory material, such as
fireclay, arranged at the sides and ends of the fie giate to protect the adjacent
portions of the tubes 4 and 9 and end walls of the casing 3 from direct contact
with the fuel on the grate.
To control the duection of the escaping hot gases and products of combustion, a
Aap on damper 12, suitably slotted to clear the blast pipe 10, or two separate flaps
oi dampers 12 arranged a short distance apart for a like purpose, and carried by a
spindle 13, may be arranged above the upper ends of the bent tubes 4 & 9 as
shown, so that when turned into the dotted position shown in Fig. 2 by an external
handle 14, it or they will permit the hot gases and products of combustion to pass
dectly to the uptake through the openings 4° and 9ª, and when turned into the
position shown in full lines in the same figue, will cause the said hot gases and
products of combustion to pass through the openings to the lower side of the
steam drum 1, and thence to the uptake
To simplify and cheapen the constinction of the steam drum and water vessel,
and to permit of access being readily gained to their interiors, the end covers of
each of them are or may be secured in place by one or more bolts passing
lengthwise completely through the steam dium or water vessel, as the case may be,
and the end covers, and provided on its on the outer ends with holding up nuts,
as shown in Figs. 1 & 2, where 1º is a central bolt with nut 1 for holding the
Covcis 1 of the steam dium in place against the ends of the drum, and 2ª is a
similar bolt with nuts 2 for holding the covers 2° of the water vessel 2 in place

page_text: against the ends of said vessel, the heads of the bolts and the nuts bearing against
the outsides of the said covers.
To separate the steam from the water projected into the steam drum I from the
upper ends of the bent tubes 4 & 9, a baille or baffles is or are provided A
convenient construction of baffle for this purpose, according to this invention, 19
shown in Figs 3 and 4 and consists of a number of bars or strips 15 arranged
parallel with each other and at a distance apart in two or more rows, the bars or
stips in one row being opposite the spaces between the bars or strips in the
adjacent row, the arrangement being such that when jets of mixed water and steam
are projected upon the baffle, the water will be arrested and the steam allowed to
pass between the bais or strips to the main steam pipe 16.
The bats are connected together at then ends by suitable carriers or supports 17,
and are preferably grooved in the duection of the length so as to be of angular,
semi-circular or equivalent form in cross section. In the example shown, they are
of angular form, and are supported within the steam dium between the upper ends
of the tubes 4 and the steam pipe 16 by plates 18, 18, the upper of which may
also, as shown, seive as a ballle for the jets of mixed steam and water issuing from
the upper ends of the tubes 9 and of some of the tubes 4
In the modified construction of boiler shown in Fig. 5, the lower ends of the
tubes 9 forming the close longitudinal wall of tubes at one side of the fire box,
instead of being reduced in diameter and bent to form bollow grate bars, are
directly secured in a water vessel 2* arinnged at the side of the fire-grate opposite
to that at which the under vessel 2 is arranged and with which it is connected by a
pipe 2 that connects the rear ends of the said vessels and is arranged outside the
boiler casing.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare that what
1 claim is
1. A water tube boiler comprising a water vessel arranged along one side of the
fire grate from front to back of the boiler, a steam dium ai ranged parallel with and
above said water vessel, a casing containing the saine, a longitudinal main group of
tubes connecting said water vessel and steam drum and arranged in a practically
diagonal manner from one side of the boiler to the other so as to divide the casing
into two longitudinal chambers the lower of which serves as the fire-box of the
boiler, and a longitudinal row of tubes connecting the water vessel aud steam drun
and arranged to extend from front to back of the boiler and to form the opposite
side of the fire-box to that constituted by the diagonal tubes, substantially as herem
descubed with reference to the drawings.
2. A water tube boiler comprising an upper steam drum, a lower water vessel, a
longitudinal main group of bent tubes connecting the upper side of said steam
drum with said water vessel, auanged to form one side and the roof of a fire-box,
and some of which are arranged to form close sides of a flue in which the remaining
tubes are arranged, said flue being in communication with the fire-box and with the
uptake of the boiler, a close wall of tubes connecting said steam dium and water
vessel and ananged to form the other side of said fire-box, and a casing with
uptake enclosing the said steam drum, water vessel and tubes, substantially as
herein described, with reference to the drawings
3. A water tube boiler m which one side of the fire-box and also the fire-giate,
are formed by a 10w of tubes made for a portion of then length smaller in diameter
than the other portions, and arranged close together for a part of then length, so
that the large parts of portions of the tubes form a close tubular fe-box wall,
and the smaller parts, which are bent to a horizontal position or approximately so,
form hollow giate bars with air spaces between them, substantially as herem
described.
4. The combination with the steam drum of a water-tube boiler, tubes arranged
to dnect streams of water and steam into the upper part thereof, and a steam

page_text: outlet pipe leading into the steam drum, of a baffle arranged within said steam
drum between the upper ends of said tubes and said steam outlet pipe and com-
prising a number of connected bars or strips grooved in the direction of their
leugth and arranged so as to alternate with each other, substantially as herein
described for the purpose specified.
5. In a water tube boiler, the combination of a longitudinal steam or water
vessel, end coveis arranged to bear against the ends of said vessel, and a bolt
extending through said vessel and covers and provided with a holding up nut the
head of said bolt bearing against the outer side of one cover and the nut against
the outer side of the opposite cover, substantially as herein described for the
purpose specified.
6. My improved water tube boiler constructed and arranged substantially as
hereinbefore described with reference to and shown in Figs 1 and 2, or modified
according to Fig. 5 of the drawings annexed, and whether or not a baffle of the
kind described and shown be used in the steam drum
Dated ... L 1
TI
1002
1033
JOHN I. THORNYCROFT.
W. Lloyd Wise,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant