IMPROVEMENTS APPLICABLE TO STEAM BOILERS OR GENERATORS
Year: 1870

page_text: LETTERS PATENT to Edwin Cambridge, of the City of Bristol,
Engineer, for the Invention of "IMPROVEMENTS APPLICABLE TO STEAM
BOILERS OR GENERATORS."
Sealed the 15th September 1870, and dated the 21th March 1870.
PROVISIONAL SPECIFICATION left by the said Edwin Cambridge at
the Office of the Commissioners of Patents, with his Petition, on
the 21th March 1870.
I, EDWIN CAMBRIDGE, of the City of Bristol, Engineer, do hereby
declare the nature of the said Invention for "IMPROVEMENTS APPLICABLE TO
STEAM BOILERS OR GENERATORS," to be as follows:-
The boilers of portable and other steam engines are usually so made
and arranged that a vast amount of heat escapes up the chimney both
from the exhaust steam pipe and from the flue tubes.
My Invention relates to a means of applying these waste heats to the
heating of the water before the latter is forced into the boiler; by this

page_text: means a great economy is effected in the consumption of fuel. To this
end I place inside the smoke box a cylindrical jacket or cistern so
arranged as to surround the ends of the fluc tubes. This jacket is
supplied with water from the reservoir, and as it is fully exposed to the
heat which comes from the fluo tubes the water soon gets hot. Round
the inside of this jacket or cistern a pipe may be laid through which the
exhaust steam will be conveyed and afterwards made to escape up the
chimney in the usual way. At the top of the jacket or cistern is an
orifice to admit of the smoke escaping up the chimney. This orifice also
forms a barrier so as to prevent a free circulation round the inside of the
jacket or cistern. Into this cistern near the top and on one side of the
orifice water is forced from a pipe in connection with a pump driven by
the engine. The water then passes round the jacket until it reaches the
other side of the smoke orifice, and is warmed on its way by the
combined action of the hot exhaust steam in the pipe inside of the jacket
or cistern and by the heat from the flue tubes on the outside. From this
point the water is forced quite hot through a pipe cither into the boiler,
or if not required there it may be returned into the supply tank or
barrel. The pump works continually, and thus maintains a constant
supply of water in circulation round the cistern, a portion of which is
always returning to the supply tank and heating the water therein
previous to its again entering the cistern. If desired the pipe for
conducting the exhaust steam through the jacket may be dispensed with
and the steam allowed to escape in the ordinary way.
SPECIFICATION in pursuance of the conditions of the Letters Patent, 25
filed by the said Edwin Cambridge in the Great Seal Patent Office
on the 22nd September 1870.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDWIN
CAMBRIDGE, of the City of Bristol, Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her 30
Letters Patent, bearing date the Twenty-fourth day of March, in the year
of our Lord One thousand eight hundred and seventy, in the thirty-
third year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said, Edwin Cambridge, Her special licence that

page_text: , "
I, the said Edwin Cambridge, my executors, administrators, and assigns,
or such others as I, the said Edwin Cambridge, my executors, adminis-
trators, 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 "IMPROVEMENTS APPLICABLE TO
STEAM BOILERS OR 'GENERATORS,' upon the condition (amongst others)
that I, the said Edwin Cambridge, 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.
NOW KNOW YE, that I, the said Edwin Cambridge, 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
following statement, reference being had to the Drawing hereunto
annexed, and to the letters and figures marked thereon (that is to
say):-
The boilers of portable and other steam engines are usually so made
and arranged that a vast amount of heat escapes up the chimney both
from the exhaust steam pipe and from the flue tubes.
My Invention relates to a means of applying this waste heat to the
heating of the feed water before the latter is forced into the boiler.
this means a great economy is effected in the consumption of fuel.
By
The Figure in the accompanying Drawing represents a vertical section
taken through the smoke box of a boiler or steam generator constructed
according to my improvements.
The outer casing of the smoke box is seen at a, a; an annular or
curved jacket or cistern 6 is placed in the smoke box so as to surround
the ends of the fluc tubes c, c, c. This cistern or water space bis
supplied with water from the ordinary reservoir or water tank through
the pipe 6, and as the cistern is fully exposed to the heat which
comes from the flue tubes the water in the cistern absorbs a great
portion of this heat and soon gets hot. Inside of this curved shaped

page_text: cistern or water space is laid a pipe d extending from end to end of the
cistern b, as shewn by dots in the Drawing; one end of this pipe is
connected to a cast-iron box d*, into which the steam passes from the
exhaust pipe d. Any condensed steam may be drawn off from this box
and returned through the pipe to the feed water tank. Through
the piped inside the curved cistern & the exhaust steam will be conveyed,
and in so doing will impart some of its heat to the water in the cistern b.
Any uncondensed exhaust steam may be allowed to escape up the
chimney. The annular or curved shaped cistern 6 does not continuc
entirely round so as to form a perfect circle, but an opening is made at
the upper part, as at e, to allow of the smoke escaping up the chimney.
It will also be evident that as the cistern is not a continuous circle the
water is impeded to a certain extent in its circulation, and is thereby
made to absorb a larger quantity of heat before it is discharged from the
cistern than if the circulation were unimpeded. Into this cistern b
near the top and on one side of it cold water is (by means of a pump
driven by the engine) forced from the pipe 6* in connection with the
tank or water reservoir. The cold water passes round the curved
cistern 6 until it reaches the other end, and is of course warmed on its
way by the combined action of the hot exhaust steam in the pipe d
inside of the jacket or cistern 6 and by the heat from the fluc tubes con
the outside. From this end of the cistern b the water is forced quite hot
through a pipe f either into the boiler, or if not required there it may be
returned through the pipe g into the supply tank or reservoir and made
to heat the water therein. The force pump works continually and thus
maintains a constant supply of water in circulation round the curved
cistern b, a portion of which water is always returning to the supply
tank and heating the water therein previous to its again entering the
cistern. If desired the pipe for conducting the exhaust steam through
the jacket may be dispensed with, and the steam allowed to escape in
the ordinary way. The water in the curved cistern will then only bo
heated by the gases escaping from the flue tubes c, c.
Having now described my Invention of "Improvements applicable to
Steam Boilers or Generators," and having explained the manner of
carrying the same into effect, I claim as the Invention secured to me by
Letters Patent as aforesaid, adapting to the smoke box of steam boilers
or generators a water jacket or cistern through which the feed water is

page_text: supplied to the boiler, and is heated by the waste escaping from the firc-
place or from the exhaust steam, as herein set forth.
In witness whereof, I, the said Edwin Cambridge, have hereunto
set my hand and scal, the Nineteenth day of September, in the
year of our Lord One thousand eight hundred and seventy.