IMPROVEMENTS IN STEAM BLOWERS
Year: 1864

page_text: LETTERS PATENT to William Brookes, of 62, Chancery Lane, in the
County of Middlesex, Civil Engineer and Patent Agent, for the Inven-
tion of "IMPROVEMENTS IN STEAM BLOWERS." -A communication from
abroad by John Theobald Hancock, of Boston, in the County of Suffolk
and State of Massachusetts in the United States of America.
Sealed the 9th June 1865, and dated the 17th December 1864.
PROVISIONAL SPECIFICATION left by the said William Brookes at the
Office of the Commissioners of Patents, with his Petition, on the 17th
December 1864.
I, WILLIAM BROOKES, of 62, Chancery Lane, in the County of Middlesex,
Civil Engineer and Patent Agent, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN STEAM BLOWERS," communicated to me from
abroad by John Theobald Hancock, of Boston, in the County of Suffolk and
State of Massachusetts, in the United States of America, to be as follows:-
The primary object of this Invention is the production of a warm, moist,
and constant blast, for increasing the energy of furnace fires, and for con-
tributing to the perfect combustion and economy of the fuel. Its secondary
objects are the ventilation of buildings, ships, and mines, and for promoting
the evaporating of liquids.
It has long been known to that portion of the manufacturing community
whose business requires the aid of fires of great intensity, that, with the same
amount of natural or artificial draught, and with equal care in firing, there is
at particular times a material diminution in the amount of work usually
performed by the same quantity of fuel arising from some peculiarity in the.

page_text: air supplied to the fire. It has also been observed that at such times the
presence of moisture in limited quantities in the ash-pit has a tendency to
cause the fires to burn more clearly, and also for the time to yield a greater
relative amount of heat. The source of such moisture has been either the
wetting of the ashes in the pit or the introduction of a steam pipe into the
ash-pit. But excepting as a mere experiment, resort is seldom had to such
expedients for the unequal diffusion of the moisture throughout the ash-pit,
and the difficulty of regulating its proper proportion usually results in
extinguishing the fire on some part of the grate, or proves to be at best of
doubtful utility.
Experiments have demonstrated that by closing the ash-pit and forcibly
introducing therein by means of fan blowing apparatus, air saturated with the
moisture from steam, not only was the energy of the combustion increased,
but a greater quantity of heat from the same amount of fuel was obtained
less clinker was formed, and, when properly applied, very little or no smoke
was produced. Further experiments resulted in the devising of simple and
useful apparatus, wherewith the air was saturated with the required amount
of moisture, and at the same time continuously forced towards and into the
fire by means of the direct action of steam upon a column of air.
Apparatus according to the improvements is shown by the accompanying
Drawings..
Figure 1 is a perspective view, and Figure 2 a detached elevation of the
steam pipes, shewing their perforations. The same letters refer to the same
parts in each of the Figures.
A, A, are a series of pipes, perforated with small holes or openings a, a,
and connected by any suitable means with a main steam pipe B. This series
of perforated tubes is affixed within the conical tube or chamber C, D, at or
near its base C, with the orifices in the pipes towards the end D. is the
opening in the pipe B, through which steam from a boiler is allowed to enter.
When apparatus of this character is connected with a furnace either by
inserting it in the wall of the ash-pit with the base of the cone outwards, or in
any more convenient location, and a pipe from a steam boiler connected with
the main pipe at b. Upon closing the door of the ash-pit, and then allowing
the steam to flow through the orifices a, a, into the tube or chamber C, D, a
continuous current of air will immediately enter the tube or chamber C, D,
through the intervals. c, c, between the perforated pipes A, A, which air is
instantly saturated with the steam, and forced onward towards and into the
fire by the steam from the jets a, a. The greater the pressure of the steam at
the jets the greater will be the quantity of air forced into the fire, and if the

page_text: outlet of the furnace remains of the same area, the greater will be the pressure
in the ash-pit. The tube C, D, is contracted at its outlet for the purpose of
retaining the air and steam in contact for a longer period than would be the
case if the tube were of constant area; but when by circumstances this tube is
necessarily prolonged to an extent of three or more diameters, such contraction
may be dispensed with without materially affecting the usefulness of the
apparatus. The object of the small outlets a, a, is to economise the steam as
the draught through the intervals between the pipes depends upon the
periphery of the jet, and not upon its area, and to furnish the proper proportion
of it to the air; if they are made too large or too numerous in the pipes, too
much steam in proportion to the air will be supplied, which will be fatal to
the object of this Invention. It has been found in practice that from sixty to
eighty holes, one thirty-second of an inch in diameter for every square foot of
surface at the plane of the tubes in the blower furnished satisfactory results.
It is not necessary that the perforated tubes be arranged as shown in the
Drawings, viz., as concentric circles; nor is it necessary that the section of
the chamber C, D, be circular, or that it be formed of metal for so long as
the principle requires that there shall be intervals between the jets for the
admission of air, and a chamber between the jet plane and the point where
the moist air is delivered, the jets can be arranged in such form as fancy or
circumstances may dictate, while the chamber C, D, must conform in section
to the arrangement of the jets. A rectangular section of chamber and the
pipes disposed in parallel lines is a good form for general practice. In some
cases it may be useful to have the axis of the tubes parallel with that of the
chamber, and the perforations in the ends instead of the sides.
When the apparatus is used for ventilation, the foul air must of course be
drawn into the blower, and then discharged therefrom into the open air or
otherwise disposed of.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Brookes in the Great Seal Patent Office on the
16th June 1865.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
BROOKES, of 62, Chancery Lane, in the County of Middlesex, Civil Engineer
and Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Seventeenth day of December, in the year of our Lord

page_text: 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 William Brookes, Her special licence that I, the said William Brookes,
my executors, administrators, and assigns, or such others as I, the said
William Brookes, my executors, administrators, and assigns, should at any
time agree with, and no others, from time to time and at all times there-
after 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 IN
STEAM BLOWERS," communicated to me from abroad by John Theobald Hancock,
of Boston, in the County of Suffolk and State of Massachusetts, in the United
States of America, upon the condition (amongst others) that I, the said William
Brookes, 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 William Brookes, do hereby declare the
nature of the said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement thereof, that is to say:-
The primary object of this Invention is the production of a warm, moist,
and constant blast for increasing the energy of furnace fires, and for con-
tributing to the perfect combustion and economy of the fuel.
Its secondary
objects are the ventilation of buildings, ships, and mines, and for promoting
the evaporating of liquids.
It has long been known to that portion of the manufacturing community
whose business requires the aid of fires of great intensity, that with the same
amount of natural or artificial draught and with equal care in firing, there is
at particular times a material diminution in the amount of work usually
performed by the same quantity of fuel arising from some peculiarity in the
air supplied to the fire. It has also been observed that at such times the
presence of moisture in limited quantities in the ash-pit has a tendency to
cause the fires to burn more clearly, and also for the time to yield a greater
relative amount of heat. The source of such moisture has been either the
wetting of the ashes in the pit or the introduction of a steam pipe into the
ash-pit. But excepting as a mere experiment resort is seldom had to such
expedients for the unequal diffusion of the moisture throughout the ash-pit,

page_text: and the difficulty of regulating its proper proportion usually results in
extinguishing the fire on some part of the grate, or proves to be at best of
doubtful utility.
Experiments have demonstrated that by closing the ash-pit and forcibly
introducing therein by means of fan-blowing apparatus, air saturated with the
moisture from steam, not only was the energy of the combustion increased,
but a greater quantity of heat from the same amount of fuel was obtained,
less clinker was formed, and when properly applied very little or no smoke
was produced. Further experiments resulted in the devising of simple and
useful apparatus wherewith the air was saturated with the required amount of
moisture, and at the same time continuously forced towards and into the fire by
means of the direct action of steam upon a column of air.
Apparatus according to the improvements is shown by the accompanying
Drawings.
Figure 1 is a perspective view, and Figure 2 a detached elevation of the
steam pipes, showing their perforations. The same letters refer to the same
parts in each of the Figures.
A, A, are a series of pipes perforated with small holes or openings a, a, and
connected by any suitable means with a main steam pipe B. This series of
perforated tubes is affixed within the conical tube or chamber C, D, at or
near its base C, with the orifices in the pipes towards the end D. is the
opening in the pipe B, through which steam from a boiler is allowed to enter.
When apparatus of this character is connected with a furnace either by
inserting it in the wall of the ash-pit with the base of the cone outwards, or in
any more convenient location, and a pipe from a steam boiler connected with
the main pipe at b. Upon closing the door of the ash-pit and then allowing
the steam to flow through the orifices a, a, into the tube or chamber C, D, a
continuous current of air will immediately enter the tube or chamber C, D,
through the intervals c, c, between the perforated pipes A, A, which air is
instantly saturated with the steam and forced onward towards and into the fire
by the steam from the jets a, a. The greater the pressure of the steam at the
jets the greater will be the quantity of air forced into the fire, and if the
outlet of the furnace remains of the same area the greater will be the pressure
in the ash-pit. The tube C, D, is contracted at its outlet for the purpose of
retaining the air and steam in contact for a longer period than would be the
case if the tube were of constant area, but when by circumstances this tube is
necessarily prolonged to an extent of three or more diameters, such contraction
may be dispensed with without materially affecting the usefulness of the appa-
ratus. The object of the small outlets a, a, is to economise the steam as the

page_text: draught through the intervals between the pipes depends upon the periphery
of the jet, and not upon its area, and to furnish the proper proportion of it to
the air if they are made too large or too numerous in the pipes, too much steam
in proportion to the air will be supplied, which will be fatal to the object of
this Invention.
It has been found in practice that from sixty to eighty holes, one thirty-
second of an inch in diameter for every square foot of surface at the plane of
the tubes in the blower furnished satisfactory results.
It is not necessary that the perforated tubes be arranged as shown in the
Drawings, viz., as concentric circles, nor is it necessary that the section of the
chamber C, D, be circular, or that it be formed of metal, for so long as the
principle requires that there shall be intervals between the jets for the
admission of air, and a chamber between the jet plane and the point where
the moist air is delivered, the jets can be arranged in such form as fancy or
circumstances may dictate, while the chamber C, D, must conform in section
to the arrangement of the jets. A rectangular section of chamber and the
pipes disposed in parallel lines is a good form for general practice. In some
cases it may be useful to have the axis of the tubes parallel with that of the
chamber, and the perforations in the ends instead of the sides.
When the apparatus is used for ventilation, the foul air must of course be
drawn into the blower and then discharged therefrom into the open air, or
otherwise disposed of.
The principle upon which this apparatus acts is as follows:-The steam as
it issues from the several jets drives forward all the air immediately in front
of them, while the air which surrounds the jets partially condenses the steam
and in return is expanded by the heat and then thrown forward loaded with
moisture by the succeeding steam, leaving a partial vacuum into which the
momentum of the steam being two great before condensation to allow it to
deviate from its path, the external air rushes from between the pipes to be in
turn expanded and driven forward. The hotter the steam the greater will be s
the amount of the vacuum, and consequently the more rapid will be the rush
of the external air to fill it; while the greater the pressure of the steam the
greater will be the pressure in the ash-pit.
When the warm and moist blast is brought forcibly into contact with the
incandescent fuel, the carbon of the fuel in the lower stratum combines with
the oxygen of the water forming carbonic acid, and the nitrogen of the air
combining with the hydrogen of the fuel forms ammonia. The hydrogen of
the water and the oxygen of the air being thus released, instantly unite to
form water, and the resultant intense heat causes the combustion of the

page_text: succeeding strata above to become more energetic, the carbon of which absorbs
a portion of the ascending acid, converting it into carbonic oxide, which
combining with the undecomposed air which has passed upward through the
fuel is again converted into acid. By properly proportioning the relative
quantities of air and moisture nearly perfect combustion and consequently
economy of fuel can be obtained.
Having thus fully described the Invention as communicated to me, I will
again call attention to the essential difference between this Invention and
those which have been made by others for a similar purpose.
In previous
methods of applying steam to fire, the steam has been admitted into the ash-
pit from a pipe, to the area of the outlet of which little or no attention has
been paid; and where such pipe has been perforated for the purpose of more
equally distributing the steam in the pit, no provision has been made whereby
the fresh air on entering the pit could have immediate and free access to each
and all of the jets. The consequence of this neglect has been that while one
portion of the fire was supplied with the proper amount of steam and air,
another part has a surplus of steam, and the remainder no steam at all. By
this Invention the steam is equally distributed over the area of the entrance
of a chamber in numerous small jets instead of pipes of comparatively large
area, and each of these jets is so placed that the surface of the issuing steam
is in contact with the entering air. (A perforated disc similar to the nose of
a watering pot will not answer the purpose for the air cannot have free access
to the more central jets.) Finally, the air and steam must be and is thoroughly
mixed before it is allowed to enter the space below the fire.
Having thus described the improvements as communicated to me, and
means adopted for carrying the same into effect, I would have it understood
that what I claim is, the improvements in steam blowers by supplying
commingled air and steam to ignited fuel in furnaces or fire-places, when the
said air and steam are mixed in a separate vessel, and introduced into a closed
ash-pit below the fire chamber.
In witness whereof, I, the said William Brookes, have hereunto set my
hand and seal, this Sixteenth day of June, in the year of our Lord One
thousand eight hundred and sixty-five.
WILLIAM BROOKES. (L.S.)