IMPROVEMENTS IN MAKING SALT FROM BRINE
Year: 1872

page_text: LETTERS PATENT to William Bull, of Chancery Lane, in the County
of Middlesex, Civil Engineer, for the Invention of "IMPROVEMENTS
IN MAKING SALT FROM BRINE."
PROVISIONAL SPECIFICATION left by the said William Bull at the
Office of the Commissioners of Patents, with his Petition, on the
19th June 1872.
I, WILLIAM BULL, of Chancery Lane, in the County of Middlesex,
Civil Engineer, do hereby declare the nature of the said Invention for
“IMPROVEMENTS IN MAKING SALT FROM BRINE," to be as follows:-
In the ordinary process of making salt from brine an oblong shallow
pan is used, under one end of which the furnaces are placed, so that the
fire there plays directly against the bottom of the said pans, and causes
a rapid deposit of "scale" therein over the said fires. This deposit of
scale (which frequently accumulates to a considerable thickness in a
few hours, adheres firmly to the bottom of the pans, and through which
the heat has to pass to the brine) greatly increases the consumption of
fuel and necessary heat in the furnaces, which causes the pan bottom
to burn away and be otherwise rapidly destroyed.
By heating the brine in the manner above described it is almost
impossible to maintain that uniformity of temperature in the pans

page_text: necessary to insure uniformity of crystallization upon which the quality
of the salt produced mainly depends.
The object of my present Invention is to make or produce salt of a
more uniform grain or crystal, and consequently of a higher commercial
value with a reduced consumption of fuel, and a greatly reduced expen-
diture in the repairs and renewal of the evaporating pans; which object
I attain by the following means, viz. :—
In order to insure a greater uniformity of heat in the brine contained
in the evaporating pan, I propose to interpose between the fires and the
said pans at one end thereof a boiler of sufficient depth for a man to
work therein when needed, and to place the furnaces under such boiler.
The steam from this boiler is free (but it may be applied under pressure
if so desired), so that the under side of the said evaporating pans can
never be heated beyond the heat of the steam. The length of the boiler
is so adjusted to the length of the pan that the heated air which passes
through the furnaces with other gases and products of combustion after
passing under and heating the said boiler, becomes so modified as not
to injuriously affect the remaining portion of the said pan, thus pro-
ducing and maintaining throughout the whole under surface of the
pans and in the brine contained therein the required uniformity of
heat by which alone regular crystals of salt, or the best quality thereof,
can be produced, and which will, in the ordinary course, command a
higher value as an article of conimerce.
My improved method of securing a uniform and moderate heat over
the whole surface of the pan, and consequently in the brine therein,
prevents that serious deposit of scale previously described, by which
a saving of about one half (more or less) the usual quantity of fuel is
effected, two furnaces doing the duty of four, as hitherto arranged.
It will be easily perceived that by my improved plan the "
wear and
tear" and renewals of the evaporting pans will thereby be very con-
siderably diminished, so much so that the bottoms of the said pans
. can never be burnt, nor be brought to so great a heat as to decompose
a portion of the salt or its scale and set free the chlorine thereof, as is
now frequently the case, which chlorine unites with and completely
destroys the iron of the said pans in a comparatively short period of
time. I estimate the saving in pans at the least of one-half the present
cost of such repairs and renewals.
1- „HRning the weste stoom of the id

page_text: boiler in the following way:-Opposite that end of the evaporating
pan under which the boiler and furnaces are placed, and at a con-
venient distance therefrom I fix another evaporating pan having a
steam-tight chamber under its bottom; the waste steam from the said
boiler is conducted to this chamber by a suitable pipe or tubes, and
the steam after parting with a portion of its heat becomes condensed,
and flows back by the same or another channel into the said boiler,
the bottom of the said chamber and the return pipe being laid to a
slight incline towards the said boiler for that purpose. By this process
much heat, which would be otherwise wasted, is fully utilized, partly
in evaporating the brine in the second or additional pan, and partly in
returning the whole of the condensed steam or water hot to the said
boiler, thus effecting a further reduction in the consumption of fuel.
I thus work two evaporating salt pans with only two fires in lieu of six
or eight such fires whon the pans are heated in the ordinary way.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Bull in the Great Seal Patent Office on
the 19th December 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
BULL, of Chancery Lanc, in the County of Middlesex, Civil Engineer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Nineteenth day of June, in the year of
our Lord One thousand eight hundred and seventy-two, in the thirty-
sixth year of Her reign, did, for Herself, Her heirs and successors, give
and. grant unto me, the said William Bull, Her special licence that I,
said William Bull, my executors, administrators, and assigns, or such
others as I, the said William Bull, 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 Islc
of Man, an Invention for "IMPROVEMENTS IN MAKING SALT PROM BRINE,”
upon the condition (amongst others) that I, the said William Bull, my
executors or administrators, by an instrument in writing under my,
or their, or one of their hands and seals, should particularly describe and

page_text: 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 Bull, 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, that is to say :-
The object of my present Invention is to make or produce salt of a
more uniform grain or crystal, to reduce the consumption of fuel, and to
save a great portion of the expense of the repairs and renewals of the
evaporating pans when constructed and heated according to the general
plan hitherto adopted.
In order to insure a greater uniformity of heat in the brine contained
in the evaporating pan I propose to interpose between the fires and the
said pans at one end thereof a boiler of sufficient depth for a man to
work in it when needed, and to place the furnaces under such boiler.
The steam from this boiler is free (but it may be applied under pressure
if so desired), so that the under side of the said evaporating pans can
never be heated beyond the heat of the steam. The length of the boiler
is so adjusted to the length of the pan that the heated air which passes
through the furnaces with other gases and products of combustion after
passing under and heating the said boiler, become so modified as not to
injuriously affect the remaining portion of the said pan, thus producing
and maintaining throughout the whole under surface of the pans and in
the brine contained therein the required uniformity of heat, by which
alone regular crystals of salt or the best quality thereof can be produced,
and which will in the ordinary course command a higher value as an
article of commerce.
My improved method of securing a uniform and moderate heat over
.the whole surface of the pan and consequently in the brine therein
prevents that serious deposit of scale previously described, by which a
saving of about one-half (more or less) of the usual quantity of fuel is
effected, two furnaces doing the duty of four as hitherto arranged.
It will be easily perceived that by my improved plan the "wear and
tear" and renewals of the evaporating pans will thereby be very con-
siderably diminished, so much so that the bottoms of the said pans can
never be burnt nor be brought to so great a heat as to decompose a

page_text: portion of the salt or its scale, and set free the chlorine thereof, as is
now frequently the case, which chlorine unites with and completely
destroys the iron of the said pans in a comparatively short period of
time. I estimate the saving in pans at the least of one-half the present
cost of such repairs and renewals.
I effect a further saving by utilizing the waste steam of the said boiler
in the following way :-Opposite that end of the evaporating pan under
which the boiler and furnaces are placed, and at a convenient distance
therefrom (or on the side or sides thereof) I fix another evaporating pan
(or pans) having a steam-tight chamber under its bottom; the waste
steam from the said boiler is conducted to this chamber by a suitable
pipe or tubes, and the steam, after parting with a portion of its heat,
becomes condensed and flows back by the same or another channel into
the said boiler, the bottom of the said chamber and the return pipo
being laid to a slight incline towards the said boiler for that purpose.
By this process much heat, which would be otherwise wasted, is fully
utilized, partly in evaporating the brine in the second or additional pan
and partly in returning the whole of the water hot to the said boiler,
thus effecting a further reduction in the consumption of fuel. I thus
work two or more evaporating salt pans with only two fires, in lieu of
six or eight of such fires when the pans are heated in the ordinary way.
The accompanying Drawing is intended to illustrate the means by
which I propose to effect the said improvements in practice.
EXPLANATION OF THE DRAWING.
Fig. 1 is a longitudinal section through the centre of a salt pan with
a boiler and furnace fitted thereto; Fig. 2 is a similar section of a
second salt pan as worked by steam from the said boiler.
a, a, a, a, is an ordinary open evaporating pan, about 60 feet long and
20 feet wide (more or less) for containing the brine; b, b, b, b, a boiler
extending nearly the full width of the brine pan, and from 12 to 20 fcet
in length (more or less) and about 2 feet 6 inches (more or less) in
depth, the depth being sufficient for a man to work in when repairs are
necessary. This boiler is fed from a reservoir or tank, not shewn in the
Drawing, with soft or pure water. c is the furnace for heating the water
and converting it into steam. The bottom of the brine pan from A to
B forms the top of this boiler, which must be well stayed to the bottom
by a sufficient number of internal plates and flanges rivetted thereto.

page_text: d, d, is a chamber formed under the said boiler and brine pan, provided
for the circulation of the heat from the furnace c and the passage of the
hot gases and products of combustion from the furnace through the end.
flue e to the main fluefconnected with the chimney. The bottom of
the brine pan from A to B is heated by the direct action of the steam in
the boiler, and from B to C by the circulation of the products of com-
bustion from the furnace C, two of the latter being sufficient for a brine
pan of the dimensions specified. is an opening in the side or end of the
boiler for the escape of the steam; from this opening a tube or pipe is
carried to a similar opening in a steam-tight chamber is formed under a
second brine pan i, i, i, i, Fig. 2, set upon the side and end walls j, Ì‚ Î‹
built or lined with cement or asphalte. The bottom of this steam-tight
chamber is formed with a dip from the sides to the centre, and with an
incline in all directions to the point where the steam enters, so that the
hot water from the steam when condensed may flow rapidly thereto, and
thence through the tube back into the boiler at a heat something, but
not much, less than the boiling point. The entire consumption of fuel
being thus reduced to that necessary for keeping the water in the boiler at
212° Fart. or the steam therein up to the required pressure. This tube
and the sides of the brine pan should be felted or covered so as to
prevent the loss of heat by radiation; and in all cases I recommend the
brine pans thus licated to be placed within a building covered with a
properly constructed ventilating roof.
In place of supporting brine pans by longitudinal or cross walls
directly upon which the bottoms of which such pans are set in the usual
way, and by which a large amount of heating surface is lost, I propose
to support the bottoms of such pans by stout hollow cylinders, as shewn
at Figs. 3 and 4, placed upon dwarf walls, placed at from 3 feet to 5 feet
apart transversely under the pans, and having openings alternately at
the centre and sides so as to cause a regular circulation of the heat from
the furnace under the whole surface of the bottom of the pan, and thus
obtain as near as possible a uniform temperature of brine.
On reference to Figs. 3 and 4 it will be seen that the bottom of the
pan d rests upon the upper rim of the cylinders A, A, the centre 6 being
hollow and the sides being formed with perforations c, c, for the heat to
enter, and these cylinders being formed of iron all diminution of heating
surface caused by walls or with ordinary iron column supports and top
caps or flanges is saved, and the entire bottoms of the pans (except

page_text: where they rest upon the side and end walls) are exposed to the action
of the heat.
Fig. 5 is a longitudinal section through the centre of a brine pan
formed in the ordinary way, and shews the mode of applying my said
Invention thereto without otherwise altering the same.
a, a, a, a, is the
pan, and b, b, b, b, the boiler, made separate from the pan and placed
between the furnace and bottom of the said pan. This boiler, fed as
before described, is formed with a number of vertical tubes c, c, c, c,
therein, through which the hot gases and products of combustion from
the furnace d pass into the chamber e, e, e, between the top of the said
boiler and under surface of the pan from A to B, and thence circulate
as before described, from B to C. In this case the opening shewn at
the inner end of the boiler (at Fig. 1) is closed by the wall d, so that the
heat from the furnaco may impinge upon the whole of the under
surface of the said boiler as well as pass through the tubes c, c, c, c.
Fig. 6 shews another modification of my said Invention, combining
the two plans shewn at Figs. 1 and 5, and also shews the general arrange-
ment of furnace heated and duplicate steam heated pans which I
recommend for adoption. a is an ordinary open brinc pan; b, b¹,
duplicate steam heated pans or two such pans (similar to that shewn at
Fig. 2; c, a boiler (for water only), placed under one end of the brine
pan; c, c, c, c, tubes through the said boiler opening into chambers d, d,
where the products of combustion impinge against a portion of the
bottom of the brine pan, the other portion of this part of the said pan
being heated by the direct action of the steam at e, e, e. The hot
air chamber under this boiler beyond furnaces is closed or partially
closed by a wall, as shewn at Fig. 5, while the hot gases and products of
combustion circulate under the brine pan and heat the brine therein
beyond the boiler, as before described at the said Fig. 5. The
hurdles h, h, on to which the salt is drawn, are placed between the
pans, as here shewn.
Fig. 7 is another modification of my said Invention, and is intended
to shew its application to an ordinary range or row of salt pans a', a², a³,
&c. In this case I take out the whole of the furnaces and form steam-
tight chambers under the pans a² and a³, as at Fig. 2, or capable of
resisting pressure when necessary, between the pans and under the
burdles c, c, I place boilers or steam generators h, h, with one furnace
under each. These boilers or steam generators and the steam tubes

page_text: therefrom, I propose to cover with felt or otherwise enclose, so as to
prevent as far as possible the waste of heat from radiation. The brine
pan a³ is heated by the steam from b³, and the brine pan a³ by the steam
from b. The brine pan a¹ is heated by the waste furnace heat from the
steam generators band b'. It will be seen that any required numbers of
pans can be worked in sets in this way.
The steam generators may be of a cylindrical or other form, and may
be placed either horizontally or vertically, preference being given to that
form of generator in which the consumption of fuel is found to be most
economical. In the application of this plan to new pans intended for
the production of common or fine salt, the generators, tubes, and steam
chambers are made of sufficient strength to work with high-pressure
steam, and by the application of ordinary lever valves this pressure and
the working temperature of the brine pans can be regulated as required,
and the formation of salt scale so destructive of the pans is almost if
not entirely avoided, the expense of repairs of renewals saved, and a
continuous and uninterrupted working of each pan insured.
For the production of rough and fishery salt, the plan shewn at Fig. 1
insures a regular and uniform heat, and consequently the production of
crystals of a regular and uniform size in all parts of the pan, a result
which it is almost impossible to obtain in furnace heated pans when
constructed and worked in the ordinary way.
Without restricting myself to the precise details shewn upon the
Drawing, I claim the several improvements thereby illustrated, and as
described in the foregoing Specification.
In witness whereof, I, the said William Bull, have hereunto set
my hand and seal, this Nineteenth day of December, in the
year of our Lord One thousand eight hundred and seventy-two.
WILLIAM BULL. (L.S.)