IMPROVEMENTS IN BOILERS OR APPARATUS APPLICABLE TO THE GENERATION OF STEAM AND TO OTHER PURPOSES
Year: 1867

page_text: PROVISIONAL SPECIFICATION left by Benjamin Harlow at the Office
of the Commissioners of Patents, with his Petition, on the 2nd February
1867.
I, BENJAMIN HARLOW, of Macclesfield, in the County of Chester, Mecha-
nical Engineer, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN BOILERS OR APPARATUS APPLICABLE TO THE GENERATION OF
STEAM AND TO OTHER PURPOSES," to be as follows:-
This Invention has for its object improvements in boilers or apparatus
applicable to the generation of steam and to other purposes, and refers to
that class of boilers or heating apparatus in which a hollow drum situated at
the upper part of the furnace is connected around or near to its circumference
by means of vertical water pipes or tubes (situated in the furnace and wholly
or partly surrounding the fire) with a hollow or water ring also surrounding
the fire and in contact with the burning fuel, the water to be heated being
contained in or circulating through the hollow drum, connecting pipes, or tubes
and ring.
Now in such boilers as hitherto constructed the pipes connecting the
drum with the ring, as described, have consisted of ordinary straight pipes
opening at one end into the drum and at the other into the ring; but
according to my Invention I make use of double pipes situated parallel to
each other, and connected together near. to the upper and lower ends of one
of the pipes. The one pipe or tube is open at its upper end to the drum and
at its lower end to the ring, the other being directly connected only (by means

page_text: of short tubular passages) with the pipe or tube before mentioned, and having
its lower end which is closed continued downward to some distance below its
lower point of connection with the other pipe or tube. When placed in
position joining the drum above and ring below the pipes or tubes which
open at both ends into the drum and ring respectively are situated farther
from the centre of the furnace than the other pipes or tubes, which latter
consequently form an inner circle more immediately exposed to the action of
the fire, and having their lower ends entirely immersed in the burning fuel;
or the ends of the inner tubes may be directly connected to the tubes of the
outer row, and the inner tubes may be curved instead of straight. Otherwise
in some cases I dispense with the inner row of tubes above described, and in
lieu thereof I construct the tubes of the outer row of a broad flat form in
such manner as that a portion of each such tube projects inwards into a
position equivalent to that occupied by the tubes of the inner rows in the
preceding arrangements, thus obtaining a broad water or steam space in each
tube. By the means described, and as the outer circle formed by the double
pipes or tubes or broad flat tubes as described is also subjected to the full
action of the furnace a large and very effective heating surface equivalent or
nearly equivalent to a double row of ordinary tubes is obtained, but with only
half the number of joints between the tubes, drum, and ring that would in
the case of such double row be necessary.
Boilers, as described, when suspended or set in furnaces of brickwork by
which they are entirely surrounded, and which leave a space between the
interior surface of the brickwork and the outer parts of the boiler, are
especially suitable for heating water for public buildings, horticultural and
other purposes, in which cases the water after being heated flows away as
required through a pipe inserted in the drum at the top of the boiler, and is
returned by a similar pipe leading into the under side of the ring at the bottom.
of the boiler, the furnace being fed from the top by means of a hole-passing
through the centre of the drum and stoked at the bottom beneath the ring of
the boiler by means of a hole passing through the side of the furnace.
Boilers as described may be used in connection with ordinary boilers and
otherwise for the generation of steam. In the case of its being used in con-
nection with an ordinary boiler, my improved boiler is set as described partly
beneath one end of the ordinary boiler, and is connected therewith by means
of a suitable pipe or pipes for maintaining a proper circulation between the
two. The flame and heated products of combustion after passing from the
furnace of the improved boiler are carried beneath or through the flues of
the ordinary boiler.

page_text: One important feature in my improved boilers is, that in the event of injury
to a double or broad flat tube, it can be readily taken out and replaced without
disturbing any other part of the boiler.
Boilers or apparatus, according to my Invention, may be conveniently
employed in the flues of puddling or other furnaces, and may likewise be
advantageously employed in the manufacture of salt from brine, the brine
passing through one or two boilers according to the quality of salt required,
and passing from them into the common evaporating pans. In some cases I
employ a fire under one boiler and heat other boilers by the products of
combustion passing from such fire.