AN IMPROVED MODE OF AND APPARATUS FOR HEATING STEAM BOILERS
Year: 1864

page_text: LETTERS PATENT to Alexander Monro, of Glasgow, in the County of
Lanark, North Britain, for the 'Invention of "AN IMPROVED MODE OF
AND APPARATUS FOR HEATING STEAM BOILERS."
Sealed the 31st March 1865, and dated the 4th October 1864.
+
PROVISIONAL SPECIFICATION left by the said Alexander Monro at
the Office of the Commissioners of Patents, with his Petition, on the
4th October 1864.
I, ALEXANDER MONRO, of Glasgow, in the County of Lanark, North
Britain, do hereby declare the nature of the said Invention of "AN IM-
PROVED MODE OF AND APPARATUS FOR HEATING STEAM BOILERS," to be as follows,
that is to say:
This Invention has for its object the improvement of the action of steam
boilers, the diminution of the requisite heating surface and fuel,-the pro-
duction of steam in a quiet and uniform manner and in a superior condition,
and the lessening of the wear of the boiler...
The Invention consists in communicating the heat to the boiler through
the medium of a substance which is. fluid at the working temperature, but
which does not readily evaporate or become decomposed, whilst it is capable
of supplying the necessary heat without being so hot as to injure the boiler
shell. Lead is a suitable and convenient substance for the purpose in view,
and in carrying out the Invention that substance is applied between the fire

page_text: and the boiler proper, being contained in a bath, jacket, or shell of a form
adapted to whatever class of boiler may be used.
-It is preferred to have the vessel containing the lead as much as possible-in
actual contact with the fire, that is, with the ignited fuel, so as to receive the
heat directly therefrom instead of receiving it from gases, which, from their
rarefied condition, can supply it but imperfectly, and it may advantageous to
form the bath with parts of its sides next the fire inclined or vertical, and
with the adjacent parts next the water also inclined or vertical, so that the
melted lead naturally rising upon the side next the fire will descend on the
side next the water.
Instead of lead any other metals which are fluid at suitable temperatures,
Alemanbetoncos nossessing similar analities may be used.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Alexander Monro in the Great Seal Patent Office on the
3rd April 1865.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALEXANDER
MONRO, of Glasgow, in the County of Lanark, North Britain, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fourth day of October, in the year of our Lord
One thousand eight hundred and sixty-four, in the twenty-eighth year of
Her reign, did, for Herself, Her heirs and successors; give and grant unto me
the said Alexander Monro, Her special licence that 'I, the said Alexander
Monro, my executors, administrators, and assigns, or such others as I, the
said Alexander Monro, my executors, administrators, and assigns,,should at
any time agree with, and no others, from time to time and at all times
thereafter during the term therein expressed, should and lawfully, might make,
use, exercise; and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for "AN
IMPROVED MODE OF AND, APPARATUS. FOR HEATING STEAM BOILERS,"..upon the con-
dition (amongst others) that I, the said Alexander Monro, my executors or
administrators, by an instrument in writing under my, or their, or..one of
their hands and seals, should particularly describe and ascertain the nature,
of the said Invention, and in what manner the same was to be performed,
and cause the same to be filed in the Great Seal Patent Office within
six calendar months next and immediately after the date of the said Letters
Patent:

page_text: NOW KNOW YE, 'that I, the said Alexander Monro; do hereby declare
the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the fol-
lowing statement in writing, and on référence to the accompanying Sheet of
Drawings, that is to say :-
My said Invention. has for its objects the improvement of the action of
steam boilers, the diminution of the requisite heating surface and fuel, the
producing of steam in a quiet and uniform manner and in a superior con-
dition, and the lessening of the wear of the boiler...
My said. Invention consists in communicating the heat to the boiler through
the medium of a substance which is fluid at the working temperature, but
which does not. readily evaporate. or become decomposed, whilst it is capable
of supplying the necessary heat. without being so hot as to injure the boiler
shell. Lead is a suitable and convenient substance for the purpose in view,,
and in carrying out my said Invention I apply that substance between the, fire.
and the boiler proper, putting it in a bath, jacket, or shell of a form adapted
to whatever class of boiler may be used.
And in order that my said Invention, and the manner of performing the
same, may be properly understood, I have hereunto appended a Sheet of
explanatory Drawings to be hereinafter referred to, and representing two:
modifications of boilers as constructed with my improvements. I must how-
ever: here remark that these two modifications are given simply as examples,:
and not as constituting the only arrangements to which my improvements, are
applicable, for the said 'improvements are obviously applicable to. boilers the
general dispositions or arrangements of which may differ very considerably
from those shown. The same reference numerals are used to mark the same
or corresponding parts in all the Figures..
Figures 1 and 2 are longitudinal and transverse vertical sections of a steain
boiler suitable for use on land. In Figure 2 the section is taken as at the
line A, B, in Figure 1; whilst in Figure 1 the section is taken as at the
line C, D, in Figure 2. The boiler comprises a horizontal cylindrical portion 1
above, and communicating with which by three connections 2 is a horizontal.
cylindrical steam chest 3. The boiler proper 1, somewhat resembles a common
internally fired two flued' boiler, but with the bottoms of the two Hues united
and forming a U-shaped flue 4, 5, the front end 4 of which forms the furnace ;"
this flue 4, 5; is.enclosed or surrounded by two shells, which separate it from..
the water, and the space 6 between these two shells is to be filled with lead, .
which can be introduced in à melted state by pipes 7 provided for the purpose.
I prefer to have the space (or vessel) 6 containing the lead as much as possible.

page_text: in actual contact with the fire, that is, with the ignited.fuel, so. as to receive
the heat directly therefrom instead of receiving it from gases, which from
their rarefied condition can supply it. but imperfectly. With this view ducts 8
are-formed-through-the-upper part of the boiler.l, so as to communicate with
the tops of the vertical parts of the U-shaped flue or furnace.space: 4, and the
coals can be introduced by these duets, and can be maintained at as great a
height as may be found desirable in practice. The cooling ducts 8 are fitted
with doors, whilst a vertical grating. 9 is adapted to the front end of the
furnace, and a series of plates 10 are fitted in front thereof for the purpose of.
regulating the admission of air required for combustion. The coal rests on
horizontal: fire-bars 11 of the ordinary kind, and beneath these there is. ther
usual ash-pit 12. The arrangement of the external. flues is, in this example,
supposed to be such that the gases leaving the back end 5 of the internal,
flue diverge and pass forwards along the sides, and then descending return by:
bottom flues to the chimney 13..
Figures 3 and 4 are sections at right angles to. each other of a marine:
boiler, as fitted with a lead bath according to my said. Invention. In this.
example an internal furnace space 4 occupies the lower part of the boiler 1,
and the gases rising from the back thereof return through tubes 14 to the
take-up 15. The roof of the furnace space is made of a deeply-undulated
form to give extended. beating surface, and the roof and sides are made with.
two shells with a space 6 between them, which space is to be fitted with lead.
as in the example herein-before described. The other parts:also are similar:
and need not be further described. I may here remark that where the sides.
of the lead bath 6 are vertical, or slightly inclined, the heat will most probably
be communicated in a way tending to induce or encourage such currents in
the water as will be most favorable to the disengagenient of the steam in. a
"dry"condition. Thus the action of the heat on the lead will probably cause
it to rise on the side next the fire, and consequently descend on the side next
the water, whilst the water in rising will be continually coming nearer hotter..
and hotter portions of the descending lead, which will promote the upward.
current of the steam.
..I.have herein-before mentioned lead. as being a suitable and convenient
substance for carrying out my said Invention; but, whilst I at present believe.
it to be the best medium for the purpose. I by no means restrict myself to it,
as any other metals which are fluid at suitable temperatures, or other sub-
stances possessing similar quantities may be used.
And having thus particularly described my said Invention, and in what.
manner the same is or may be performed, I have to state that what I believe

page_text: to be novel and. original and claim as the Invention secured to me by the
herein-before in part .recited Letters Patent is, the communicating of heat to
steam boilers through the medium of a substance such as lead, which is fluid
at the working temperature, substantially in the manner and for the purpose
herein-before described..
In witness whereof, I, the said Alexander Monro, have hereunto set my
hand and seal, this -Thirty-first day of March, in the year of our Lord
One thousand eight hundred and sixty-five.
ALEXANDER MONRO. (L.S.)