IMPROVEMENTS IN THE CON- STRUCTION OF BOILERS FOR HEATING AND CIRCULATING WATER
Year: 1876

page_text: LETTERS PATENT to John Metcalf, of Preston, in the County of Lancaster,
Hot Water Engineer, for the Invention of "IMPROVEMENTS IN THE CON-
STRUCTION OF BOILERS FOR HEATING AND CIRCULATING WATER."
Sealed the 14th July 1876, and dated the 10th May 1876.
PROVISIONAL SPECIFICATION left by the said John Metcalf at the Office
of the Commissioners of Patents on the 10th May 1876.
JOHN METCALF, of Preston, in the County of Lancaster, Hot Water Engineer.
"IMPROVEMENTS IN THE CONSTRUCTION OF BOILERS FOR HEATING AND CIRCULATING
WATER."
This Invention is designed to afford within a given size of boiler more heating
surface and more effectual distribution of the heat generated in the furnace, so as
to produce more mpid and economical heating and circulation of the water than in
boilers of the constructions at present usually employed for heating and circulating
water as distinguished from steam boilers.
My improved boiler is arranged vertically. It is constructed with two annular
water chambers arranged one above the other, and in communication with each other,
as also (through two rows of tubes, as herein-after described) with a hollow water
casing or fire-box surrounding the fire-guate. The tubes constituting the outer row
establish communication between the periphery of the lower annular water chamber
and the top of the water casing. These tubes, for the greater part of their length,
are nearly triangular in section, the base of the triangle being to the sides as one
and a half is to four, or thereabouts; the base and apex are rounded, the latter
having upon its edge a feather or strip of metal running lengthwise along that
portion of the tubes where the triangular form obtains. The tubes are arranged
side by side vertically, or nearly so, in a circle, and the two wider sides of the
triangle of each tube are so placed as to have their surfaces exposed to the action
of the products of combustion as they pass from the fire below. The thin edges
of the triangular tubes point inwardly. A second series or row of tubes of equal
number with the first is placed within the others in such a way as that the draught
shall flow between the two series of tubes, and also along the outside of the outer
row. The outer tubes are curved at their upper ends, which are fitted into circular
sockets running along the outer edge or periphery of the lower annular water
chamber. The tubes in the second or inner row are oval or cliptical in section,

page_text: except at the top and bottom ends, which are rounded and fitted to the lower
annular water chamber and to the water casing or hollow fire-box in the same
manner as the outer tubes, excepting that the tubes of the inner row are curved at
their lower ends and are connected to the inside of the water casing or hollow fire-
box. The edges of the inner tubes stand opposite the feathers on the inner edges
of the outer tubes, the tubes of the respective rows being arranged opposite to
each other in pairs. The tubes of the inner row are set at a slight distance from
each other, the spaces between them being occupied by feathers running lengthwise
on each side of the oval or eliptical tubes, of the same length as those on the outer
tubes.
Those portions of the tubes, both of the inner and outer series, which are curved
are of reduced bulk, being of the same diameter as the circular portions which
enter the sockets in the lower annular water chamber and in the water casing or
hollow fire-box, so as to allow room for the ingress of flamme, &c., from the fire to
the space between the two sets of tubes, and thence to the space between the two
upper chambers, as described below.
When the boiler is in position for work the brickwork enclosing the boiler is set
at a little distance from the outer surfaces of the tubes, but is built up to the
periphery of the upper water chamber. Between the lower water chamber and the
upper one is inserted a rim or thin hoop of metal of slightly greater diameter than
the circular apertures in the centre of the upper and lower water chambers; and
near to the outside of the lower chamber, which is of considerably less diameter
than the upper one, are fitted, one on each side, midfeathers which, at one side of
the boiler are continued to the outer edge of the upper chamber, a suitable projection
being formed on the corresponding portion of the lower one, on which the lower
edge of the mid-feathers may rest. The other ends of the mid-feathers terminate
at a sufficient distance from each other to leave an open space or passage.
When the boiler is at work the fire acts first upon the inner surface of the water
casing or hollow fire-box, being contained within it, whence the flow of the
products of combustion will be to the spaces between cach two pairs of the inner
and outer tubes, and thence they (the products of combustion) will ascend between
the tubes to the upper portion of the boiler, where they will impinge against the
under side of the upper water chamber, at length finding their way into the two
passages or flues formed by the arrangement of mid-feathers between the upper and
lower annular water chambers.
The water chambers and water casing or hollow fire-box respectively may be
made in independent sections or parts.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Metcalf in the Great Seal Patent Office on the 8th November
1876.
"
JOHN METCALF, of Preston, in the County of Lancaster, Hot Water Engineer.
IMPROVEMENTS IN THE CONSTRUCTION OF BOILERS FOR HEATING AND CIRCULATING
WATER."
This Invention is designed to afford within a given size of boiler more heating
surface and more effectual distribution of the heat generated in the furnace, so as
to produce more rapid and economical heating and circulation of the water than in
boilers of the constructions at present usually employed for heating and circulating
water as distinguished from steam boilers.
My improved boiler (of which Fig. 1 is a front elevation and Fig. 2 a section) is
arranged vertically. It is constructed with two annular water chambers a and b
arranged one above the other (and in communication with each other by means of
tubes n, n) as also (through two rows of tubes, as herein-after described) with a

page_text: hollow water casing or fire-box c surrounding the fire-grate. The tubes constituting
the outer row d, d, d, d, establish communication between the periphery of the
lower annular water chamber and the top of the water casing c These
tubes d, d, d, d, for the greater part of their length, are nearly triangular in section
(see Fig. 4), the base of the triangle being to the sides as one and a half is to four,
or thereabouts; the base and apex are rounded. The tubes are arranged side by
side vertically, or nearly so, in a circle, and the two wider sides of the triangle of
each tube are so placed as to have their surfaces exposed to the action of the
products of combustion as they pass from the fire below. The thin edges of the
triangular tubes d, d, d, d, point inwardly. A second series or row of tubes e, c, c, c,
is placed within the others in such a way as that the draught shall flow between
the two series of tubes, and also along the outside of the outer row. The outer
tubes d, d, d, d, are curved at their upper ends 1, which are fitted into circular
sockets ffff, running along the outer edge or periphery of the lower annular
chamber 6. The tubes e, e, e, e, in the second or inner row are oval or elliptical in
section, except at the top and bottom ends, which are rounded and fitted to the
lower annular water chamber b and to the water casing or hollow fire-box c in the
saine manner as the outer tubes, excepting that the tubes of the inner row are
curved at their lower ends 2, and are connected to the inside of the water casing or
hollow fire-box c. The tubes of the inner row are set at a slight distance from each
other, the spaces between them being occupied by feathers g, 9,9,g, running length-
wise on each side of the oval or elliptical tubes.
Those portions of the tubes, both of the inner and outer series, which are curved
are of reduced bulk, being of the same diameter as the circular portions which
enter the sockets and f in the lower annular water chamber band in the water
casing or hollow fire-box c, so as to allow room for the ingress of flame, et cætera,
from the fire to the space between the two sets of tubes, and thence to the space
between the two upper chambers, as described below.
When the boiler is in position for work the brickwork o enclosing the boiler is
set at a little distance from the outer surfaces of the tubes d, d, d, d, but is built
up to the periphery of the upper water chamber a. Between the lower water
chamber band the upper one a is inserted a rim or thin hoop of metal h of slightly
greater diameter than the circular apertures i and in the centre of the upper and
lower water chambers, and near to the outside of the lower chamber b, which is of
considerably less diameter than the upper one a, are fitted, one on each side, mid-
feathers and (Fig. 3) which, at one side of the boiler, are continued to the outer
edge of the upper chamber a, a suitable projection being formed on the corres-
ponding portion of the lower one b, on which the lower edge of the mid-feathers
rest. The other ends of the mid-feathers terminate at a sufficient distance from
each other to leave an open space or passage 3.
When the boiler is at work the fire acts first upon the inner surface of the water
casing or hollow fire-box c, being contained within it, whence the flow of the
products of combustion will be to the space between the inner and outer row, and
also along the outside of the outer row, and thence they (the products of combustion)
will ascend between the tubes to the upper portion of the boiler, where they will
impinge against the under side of the upper water chainber a, at length finding
their way through the opening 3 into the two passages or flues 4, 4, formed by the
arrangement of metal hoop or rim and mid-feathers j and j' between the upper and
lower annular water chambers.
The water chambers and water casing or hollow fire-box respectively may be
made in independent sections or parts.
The boiler shewn in Figs. 1, 2, and 3, is constructed in two parts. The right-
hand half of Fig. 3 shews the boiler in plan, and the other half is a plan view with
the upper water chamber removed, shewing the arrangement of the lower water
chamber, and the mid-feathers forming the passages or flues 1, 1; and 1,, are
socket openings for the flow and return respectively of the water from and to the
boiler..

page_text: The fuel is fed to the boiler from the top through the apertures i and i¹; m is a
lid or cover which closes the aperture i, so as to prevent the access of air from the
top of the boiler during combustion.
Having described the nature of my said Invention, and explained the mode of
carrying it into practical effect, I desire to have it understood that I do not intend
to claim generally the use of an upper and a lower water chamber connected by
tubes, as I am aware various arrangements of water-heating apparatus have been
constructed on that plan, nor do I claim as of my Invention or the exclusive use of
any of the several parts herein-before described or referred to apart from the
application and use thereof in combination, as and for the purposes herein-before
shewn and described, but what I consider to be novel and original and therefore
claim as the Invention secured to me by the herein-before in part recited Letters
Patent is, the combination of parts constituting the improved boiler for heating
and circulating water, constructed, arranged, and operating substantially as herein-
before described and shewn in the Drawings.
In witness whereof, I, the said John Metcalf, have hereunto set my hand and
scal, this Sixth day of November, in the year of our Lord One thousand
eight hundred and seventy-six.
JOHN METCALF. (LS.)