IMPROVEMENTS IN STEAM AND OTHER BOILERS, AND SUPERHEATING, CONDENSING, REFRIGERATING, AND EVAPORATING VESSELS AND APPARATUS, AND IN THE PLATES AND TUBES EMPLOYED
Year: 1870

page_text: PROVISIONAL SPECIFICATION left by Thomas Webster Rammell at
the Office of the Commissioners of Patents, with his Petition, on
the 16th February 1870.
I, THOMAS WEBSTER RAMMELL, of 3, Westminster Chambers, West-
minster, in the County of Middlesex, Civil Engineer, do hereby declare
the nature of the said Invention for "IMPROVEMENTS IN STEAM AND OTHER
BOILERS, AND SUPERHEATING, CONDENSING, REFRIGERATING, AND EVAPORATING
VESSELS AND APPARATUS, AND IN THE PLATES AND TUBES EMPLOYED," to be as
follows:-
The steam boilers hitherto in use are constructed of metal plates
or of a combination of metal plates and of metal tubes of larger or
smaller diameter, and such plates and tubes have flat or plane surfaces,
that is to say, a given area let it be a square foot of a plate or of the
surface of a cylindrical or conical tube presents on the one side a square
foot only of absorbing surface to the action of the fire or contact with
the heated gasses, and on the other side a square foot only of emitting or

page_text: communicating surface to contact with the water to be heated, although
the capacity of the metal for transmitting heat through a given area.
is probably much greater than either that of the heated gasses for
giving it out or of the water for taking it up.
The same description applies to all other boilers and to all other
vessels or apparatus where plates or tubes are employed for transmitting
heat to or discharging heat from water or the vapour of water whether
for applications of motive power or for manufacturing purposes. These
equal-proportions-of-substance-and-surface-areas-in-the-plates-and-tubes-
are productive of inefficiency and waste, and one of my improvements
consists in so making the plates and tubes for such boilers and vessels
that any given area, say a square foot of a plate or a tube, shall present
more than a square foot of absorbing or of emitting surface or of both,
as the case may be, and thus give frecer play to the conducting capacity
of the metal. I effect this object by raising certain parts of the substance
of the plate or the tube above other parts, thus obtaining in the sides
of the raised parts an additional surface for fluid contact. I produce
the raisings with the intervening depressions on one or on both sides
of the plate or the tube and in such manner and degree on either side
as under the circumstances of the case may appear to be desirable.
I prefer to make the raised or projecting parts of such form that they
shall add to the strength of the plate or the tube, and be readily pro-
duced out of the substance of the metal in the process of manufacture.
Thus a ribbed and fluted or a ribbed and cellular pattern is very
suitable for the purpose, since it may be readily produced and may
be so applied as to add materially both to the surface and to the
strength of the plate or the tube. I vary the thickness and depth of
the ribs, their distances apart, and relative directions according to
circumstances.
Another of my improvements consists in a particular arrangement
of the tubes of steam boilers. The general arrangement I adopt is what
is known as the vertical, cylindrical, and dome-topped boiler. From the
inner dome of the fire-box a faggot of tubes rises and is ordinarily led
through the water and into an ascending flue. These rising tubes
from the fire-box I connect together in sets by a series of horizontal
tubes below the water line, which horizontal tubes are again connected
with an annular series of vertical descending tubes placed around the

page_text: fire-box and in connection with an outer annular flue leading to the
chimney. By this arrangement the heated currents of air are passed
for an additional length through the water before they are allowed to
escape, and they never rise above the water level in the boiler.