IMPROVEMENTS IN PRODUCING. AND SUPERHEATING STEAM
Year: 1866

page_text: LETTERS PATENT to George Tomlinson Bousfield, of Loughborough Park,
Brixton, in the County of Surrey, for the Invention of "IMPROVEMENTS
IN PRODUCING. AND SUPERHEATING STEAM." - A communication from
abroad by James Farquharson McKenzie, residing at Melbourne, in
the Colony of Victoria.
Sealed the 15th January 1867, and dated the 23rd July 1866.
PROVISIONAL SPECIFICATION left by the said George Tomlinson
Bousfield at the Office of the Commissioners of Patents, with his
Petition, on the 23rd July 1866.
I, GEORGE TOMLINSON BOUSFIELD, of Loughborough Park, Brixton, in the
County of Surrey, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN PRODUCING AND SUPERHEATING STEAM," to be as follows:-
The object of this Invention is to provide a continuous supply of super-
heated steam at a given temperature and at a regulated pressure. To
accomplish this object I regulate the pressure and the temperature bydistinct
means, each being in no degree dependent upon the other.
I will illustrate the Invention thus :-I provide a 2-inch pipe, say, 20 feet
long, and inside this pipe I place, say, 7 stops or divisions about 2 feet apart,
each of these divisions having orifices so as to connect the different compart-
ments together. I place this pipe inside a flue from a reverberatory furnace.
At the end nearest the fire I introduce cold water from a suitable supply
Prime 811

page_text: pipe; as it enters the first compartment it will be heated to a certain extent,
and as it continues its journey through the other compartments it will
gradually increase its heat until it becomes steam, the mean temperature of
each compartment increasing as it travels along, and go on increasing until it
attains to a temperature of, say, 400 degrees Fahrenheit. Here I propose to
place underneath and inside the heating pipe a thermostat which is connected
to a spindle passing through a stuffing box, and which spindle is connected
with the water supply pipe, so that if the temperature should rise above the
required height a greater body of water would be injected into the heating
pipe and the temperature thus reduced; and, on the other hand, if the
temperature should sink too low, an opposite course would be occasioned by
the action of the thermostat with of course an opposite result. In order to
regulate the pressure I place (say above the pipe) a piston with a rod
passing through a stuffing box, weighted according to the amount of pressure
required. The extremity of this rod is connected with the damper, so that
when the pressure rises above that required the dampers are closed or
partially so, and the result is of course a decrease in the heating power and
in the amount of water converted into superheated steam and a consequent
diminution of pressure. It will be thus seen that the temperature and the
pressure are regulated totally irrespective of each other. Whatever be the
amount of water which arrives at the extremity of the pipe, whether it be
little or much, must arrive there at the temperature required by the action of
the thermostat, whilst the pressure gauge controls and regulates the pressure
of the steam whatever the temperature may be. I have referred to a single
pipe with divisions to illustrate this Invention, but I believe it will be found
more practicable for many reasons to make separate short pipes for each
compartment parallel to one another and connected together by smail pipes.
SPECIFICATION in pursuance of the conditions of the Letters
Patent, filed by the said George Tomlinson Bousfield in the Great
Seal Patent Office on the 23rd January 1867.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
TOMLINSON BOUSFIELD, of Loughborough Park, Brixton, in the County of
Surrey, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-third day of July, in the year of our Lord
One thousand eight hundred and sixty-six, in the thirtieth year of Her

page_text: reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said George Tomlinson Bousfield, Her special licence that I, the said
George Tomlinson Bousfield, my executors, administrators, and assigns, or
such others as I, the said George Tomlinson Bousfield, 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 "IMPROVEMENTS IN PRODUCING AND SUPERHEATING STEAM,"
a communication to me from abroad by James Farquharson McKenzie, a
person resident at Melbourne, in the Colony of Victoria, upon the condition
(amongst others) that I, the said George Tomlinson Bousfield, 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 George Tomlinson Bousfield, do hereby
declare the nature of the said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and by
the following statement thereof, that is to say:--
The object of this Invention is to provide a continuous supply of super-
heated steam at a given temperature and at a regulated pressure. To
accomplish this object I regulate the pressure and the temperature by
distinct means, each being in no degree dependent upon the other.
I will illustrate the Invention thus :-I provide a 2-inch pipe, say 20 feet
long, and inside this pipe I place, say, 7 stops or divisions about 2 feet apart,
each of these divisions having orifices so as to connect the different compart-
ments together. I place this pipe inside a flue from a reverberatory furnace.
At the end nearest the fire I introduce cold water from a suitable supply pipe;
as it enters the first compartment it will be heated to a certain extent, and as
it continues its journey through the other compartments it will gradually
increase its heat until it becomes steam, the mean temperature of each
compartment increasing as it travels along, and go on increasing until it
attains to a temperature of, say, 400 degrees Fahrenheit. Here I propose
to place underneath and inside the heating pipe a thermostat which is
connected to a spindle passing through a stuffing box, and which spindle is
connected with the water supply pipe, so that if the temperature should

page_text: rise above the required height a greater body of water would be injected into
the heating pipe and the temperature thus reduced, and, on the other hand,
if the temperature should sink too low an opposite course would be
occasioned by the action of the thermostat, with of course an opposite result.
In order to regulate the pressure I place (say above the pipe) a piston with
a rod passing through a stuffing box weighted according to the amount of
pressure required. The extremity of this rod is connected with the damper,
so that when the pressure rises above that required the dampers are closed, or
partially so, and the result is of course a decrease in the heating power
and in the amount of water converted into superheated steam, and a con-
sequent diminution of pressure. It will be thus seen that the temperature
and the pressure are regulated totally irrespective of each other. Whatever
be the amount of water which arrives at the extremity of the pipe, whether
it be little or much, must arrive there at the temperature required by the
action of the thermostat, whilst the pressure gauge controls and regulates
the pressure of the steam whatever the temperature may be. I have referred
to a single pipe with divisions to illustrate this Invention, but I believe
it will be found more practicable for many reasons to make separate short
pipes for each compartment parallel to one another and connected together
by small pipes.
DESCRIPTION OF THE DRAWINGS.
Figure 1 shows a side elevation in section; Figures 2, 3, and 4 show
respectively a cross section,a longitudinal section, and a plan of the generator;
and Figure 5 shows some of the pipes and connection full size.
M, Figure 2, is the first pipe to receive the water supply; N is the super-
heated steam pipe in which the thermostat would be placed; O is safety
valve for steam chest; A, Figure 1, water supply pipe with pressure greater
than that at which the generator is to be used; B, water regulating and
. shut off valve, actuated by a thermostat; C, pipe conveying adjusted supply
of water to furnace end of generator; D, generator enclosed in a flue through
which the products of combustion pass in the direction of the arrows;
E, stops in the generator perforated in the centre with small holes about
th of an inch area for each horse power, so that for one horse power the
orifice would be nearly 4th of an inch diameter; F, thermostat made of the
ordinary brass and iron bars rivetted together and twisted round a spindle so
that the spindle will revolve in the one or other direction by every change of
temperature; f, arm or spindle of thermostat, through which its movements
regulate the water supply, or other forms of thermostats may be used; G,solid

page_text: piston passing through stuffing box, and pressed down with a spring or
loaded with a weight equal to that at which the pressure of the steam in
the boiler is to be maintained; H, spring or weight pressing on the head of
the solid piston; I, steam reservoir; J, ordinary safety valve; K, supply
pipe to engine; L, rod connecting piston G with furnace damper. For
the convenience of explanation the generator is shown in the form of a
straight tube, but the practical one is intended to pass and repass through a
heating chamber, and where it passes through the walls of such chamber it
will be furnished with plugs at each bend which can be periodically with-
drawn for the purpose of removing any sediment that may collect in the
tubes. In practice it is intended that each tube shall have a heating surface
of 4 horse power, and in large engines, whatever number of tubes may be
necessary for the required horse power, each tube will have to be furnished
with an independent thermostat and water supply, but onlyonepressureplunger,
as the prearranged pressure is common to all the tubes, and they are
connected through the steam reservoir. Suppose the working pressure at
which the furnace damper begins to shut the 50 lbs. above the atmospheric
pressure and the thermostat is so arranged that before the temperature of the
steam by which it is surrounded falls to 350° the water supply will be com-
pletely cut off, that before it rises to 450° it admits a supply of water greater
than the heating-surface of the generator can evaporate and raise to that
temperature.
These conditions being understood the action of the generator is as
follows:-Suppose the engine at work, the necessary supply of water will be
passing into the generator at the ordinary temperature of feed water, say, 60°,
and that the heating surface of the first division D is equal to raise the
quantity of water passing through it 100° higher, it is clear that the water
will pass through the orifice into the second division D¹ at a temperature of
at least 160°. If a corresponding accession of heat takes place in the next
division D" a temperature of 260° would be reached before the water would
pass through the orifice into the third division D", and if a similar further
accession of heat be communicated in that division it would pass into the
fourth in the condition known to engineers as "primed," that is, a mixture of
steam and water, the temperature of saturated steam at the working pressure
having been reached. As the steam passes through the following divisions it
becomes superheated, but can never, even as superheated steam, exceed the
prearranged temperature of 450°, as before reaching that temperature the
thermostat admits a greater quantity of water than the generator can heat
up to that temperature. On the thermostat's admitting a greater quantity of

page_text: water than the requirements of the engine the pressure would increase in the
reservoir I, and the solid plunger G would shut the furnace damper and
lessen the intensity of the combustion; the steam would immediately pass
into the thermostat chamber at a lower temperature and the thermostat
would shut off the excess of the supply of water as it could not admit any
water when the temperature is as low as 50°, and an excess of water would
be admitted at the other extremity of its range. Suppose through fluctuations
in the work the requirements of the engine are diminished, the pressure rises
in the steam reservoir and the action of the solid plunger G shuts the damper
and lessens the intensity of the combustion; on the intensity of the com-
bustion being lessened the steam would flow into the thermostat chamber at a
lower temperature and the excess of water would be shut off. Suppose on the
other hand that the load on the engine,and consequently its requirements, were
increased, the pressure in the reservoir would be lowered. The furnace
damper would be opened to a greater extent and the intensity of combustion
increased, the superheated steam would pass into the thermostat chamber
at a higher temperature, and the action of the thermostat would immediately
admit additional water corresponding to the increased load on the engine,
and, so to speak, the equilibrium of the whole apparatus would be again
established. In examining the action of the generator the fact must not be
overlooked that the water cannot pass faster out of any compartmentthan it
is admitted into it.
The great peculiarity of this generator is that it renders practicable the
working of the pressure of superheated steam and its temperature as two
independent quantities. The pressure, which is the measure of power,
regulates the combustion of the furnace and the temperature regulates the
quantity of water introduced. Mere temperature is not power, although the
increase of all matter from a lower to a higher temperature is, of which
power the pressure of the expansive agent is the measure.
One of the great difficulties with superheated steam hitherto has been its
extreme fluctuations of temperature and the impossibilit of controling them.
It is imperative that an engine cylinder be kept nearly constant in tempe-
rature, as the expansions and contractions due to variations soon destroy both
piston and cylinder and render it impossible to keep them steam-tight.
The advantages of this steam generator are,-
First, perfect safety in working, as even the rupture, though improbable,
of a compartment could not produce an explosion, the area and rupture
being small and there being no quantity of water and steam in the generator.
Second, great economy of fuel, as, the superheating being constant and

page_text: certain, the steam can be wrought expansively without any objectionable
condensation in the cylinder.
Third, the possibility of working with perfect safety when advisable at very
high pressures, thus reducing the weight and bulk of the engine to a minimum.
Fourth,lowness of cost, the generator not costing half as much as a common.
boiler of corresponding power.
Fifth, great lightness and portability, the generator and its contents
certainly not weighing more than twenty or twenty-five per cent. of those
of a corresponding boiler.
Sixth, the possibility of repairing or replacing any part of it with very
little trouble, a very great advantage over common boilers.
Seventh, no loss of time in getting up steam, there being no bulk of water
to heat, the thermostat would admit water, and consequently the engine
be ready to start a few minutes after the fire is lighted.
In witness whereof, I, the said George Tomlinson Bousfield, have hereunto
set my hand and seal, this Seventeenth day of January, in the year
of our Lord One thousand eight hundred and sixty-seven.
GEO. T. BOUSFIELD. (L.S.)