IMPROVEMENTS IN FURNACES, BOILERS, PANS, AND THEIR ACCESSORIES AND APPLIANCES USED FOR THE MANUFACTURE OF SALT
Year: 1881

page_text: LETTERS PATENT to Thomas Barrow, of Rock Ferry, in the County of Chester,
for an Invention of "IMPROVEMENTS IN FURNACES, BOILERS, PANS, AND
THEIR ACCESSORIES AND APPLIANCES USED FOR THE MANUFACTURE OF
SALT."
PROVISIONAL SPECIFICATION left by the said Thomas Barrow at the Office
of the Commissioners of Patents on the 25th August 1881.
THOMAS BARROW, of Rock Ferry, in the County of Chester. "IMPROVEMENTS
IN FURNACES BOILERS, PANS, AND THEIR ACCESSORIES AND APPLIANCES USED
FOR THE MANUFACTURE OF SALT."
This Invention relates
Firstly, to improvements in furnaces to be used under pans for the manufacture
of salt, such furnaces being also applicable to boilers, and for purposes other than
the manufacture of salt, namely, in most cases where surface evaporation by heat
in practised.
Secondly, to improvements in boilers in connection with the furnaces under the
first part.
Thirdly, to improvements in pans for concentrating brine in connection with the
furnaces under the first part.
Fourthly, to improvements in scraping or raking appliances in connection with
pans under the third part.
Fifthly, to improvements in apparatus for condensing smoke and noxious vapours
given off from furnaces under the first part.
Sixthly, to a method of and appliances for granulating lump salt produced from
pans of the third part.
Seventhly, to a method of and appliances for separating, purifying, and grading
salt granulated by the appliances under the sixth part.
Under the first part I construct a furnace consisting of a circular flue in which
is fitted a system of travelling fire bars or fire brick slabs. The fire bars are carried
by bearers and brackets or frames, which latter travel along a rail placed in the
bottom of the circular flue, the brackets or bearers being provided with rollers or
[Price 8d1

page_text: wheels, and with a continuous toothed band or ring which connects the several
brackets or bearers together, and is constructed so that a pinion at the side of the
furnace which gears into the teeth of the ring can be used for rotating the furnace.
The furnace is thus a continuous circular fuel receptacle, which is arranged to
slowly rotate in the flue past the firing door, next to which is a damper preferably
of a fire brick slab perforated, and a flue that leads the heat, smoke, and gaseous
products of combustion from the furnace and through flues arranged under other
portions of the salt pan or boiler, as the case may be.
A modification of this circular or ring arrangement of furnace consists in forming
the fuel receptacle stationary and in the form of a straight tunnel or flue of
concave fire brick slabs, and providing therein a series of rotating screws, the upper
portion only of which are exposed to the fuel as the screws revolve, which revolving
motion is imparted to them by suitable gearing under the furnace.
The object
attained by the rotary or screw construction of furnace is the working of the
incandescent fuel away from the supply of fresh or green fuel, so that the gases and
smoke from the green fuel have to pass over the incandescent or burning fuel and
are thereby consumed.
"
Furnaces thus constructed are placed under one end or side of the salt pan, and
the flues ramify under the salt pan to the other end or side, and are finally led to a
stove and then to other pans, and to the chimney.
Under the second part I construct a boiler of vertical cylindrical form with a
dome top, the interior of which is constructed of concentric chambers, being water
spaces and heating spaces. The boiler is arranged to fit over the furnace described
under the first part, and is provided at its lower part with a flue corresponding
with the flue of the circular -furnace. This flue ramifies concentrically in one or
more tiers through the interior of the boiler, forming therein concentric chambers
which are heating chambers, and concentric spaces which are water spaces.
Under the third part I construct pans for concentrating brine (to be placed over-
the furnaces under the first part) of about fifty feet in length by twelve feet in
width and of the usual depth, with straight sides and bevel ends. Fitting within
the pans and running longitudinally therewith I form a wooden covering supported
by wooden pontoons which float the covering on the surface of the brine. This
covering may be conveniently made in four widths, leaving a space between them
to allow for a scraper. I provide the pans with funnels or shafts to remove the
steam or vapour.
Under the fourth part I construct a raking or scraping appliance of a flat vertical
board, or iron or steel plate, with a handle or stale which runs in the space between
the covering boards. The stale is provided with two wheels, which support the
scraper and run on the covering or supporting boards. The operator in use walks
on the covering boards and scrapes the salt lengthways of the pan instead of
crossways, as at present practised, and up against the brine supply, which tends to
wash the salt.
Under the fifth part I construct an apparatus to which the smoke and noxious
gases from the furnace and pans is led. This apparatus consists of a conical tower,
within which I construct shelves or trays and an interior cylindrical shaft, into
which certain of the spaces formed by the shelves or trays open. The spaces
between the shelves or trays form flues through which the smoke and noxious gases
pass. The bottom of each alternate tray or flue is perforated, and each alternate
Hue is connected by an uptake, at the mouth of each of which is a small water
wheel or distributor. The smoke and noxious gases find their way up between
and through the alternating flues, and are treated and condensed by water
showering through and down the flues from the top of the apparatus.
The
apparatus is also applicable as a condenser for noxious smokes, fumes, and gases of
chemical works other than salt works.
Under the sixth part, when the salt has been moulded into lumps after
concentration in the pans of the third part, I granulate the lump salt by an
apparatus which consists of a reciprocating board or band or an endless band which

page_text: carries lateral blades or plates, the edges of which are serrated. The rubbing or
friction of these serrated edges against the lump salt separates and breaks the
crystals and grains of the salt without deadening them, which is the result of
crushing the salt by rollers or beaters.
Under the seventh part, after the salt has been granulated by the apparatus
described under the sixth part, I pass such granulated salt through a series of
trays placed one over the other, the bottoms of which are formed of wire, silk, or
other gauze. From each of these trays I lead shoots, and within the trays I
provide revolving brushes which brush the salt through the trays, which may be
of different meshes so as to deliver different grades of salt. The upper tray is the
coarsest, and is used for removing panscale and other impurities.

page_text: Invention.
Figure 14 is a sectional plan through Y, Y, Figure 13.
Figure 15 is a modification of Figure 13.
Figure 16 is a sectional plan through Y, Y, Figure 15.
Figure 17 is a sectional elevation showing the application of this Invention to
brewers' pans.
Figures 18, 19, and 20 illustrate the method of granulating and sifting salt
according to this Invention.
Under the first part I construct a furnace consisting of a circular flue A (see
Figures 1, 2, 3, 4, 5, 10, 13, 15, and 17). In the circular flue A I provide a system
of travelling fire bars or fire brick slabs B, which constitute the furnace. The fire
slabs B are carried by the bearers or frames C, which latter are tied together by
the ring bars D and the toothed ring rack D¹. The frames C are provided with
the wheels E, and together with the slabs B form a continuous furnace, which
travels round on the circular rail F in the flue A, the plate G forming the ash pan.
An alternative for the wheels E and rail F is shown at Figure 6. In this case the
gutter rail F is used, and rolling balls E are substituted for the wheels. A circular
furnace being thus constructed it is rotated in the flue A by the gearing H, which
may consist of a system of toothed wheels gearing into the circular rack D¹; worm
gearing may if desired be substituted for the toothed wheel gearing. The furnace
constitutes a continuous circular fuel receptacle, which is arranged to be inter-
mittently rotated in the flue A, past the firing door J, next to which is a damper K,
preferably of a fire clay slab perforated. There are flues from the circular furnace
that lead the heat, smoke, and gaseous products of combustion from the furnace,
and through flues arranged under other portions of the salt pan or boiler, as may
be desired. I is a door for withdrawing the spent fuel and clinkers. In Figures
1, 2, 3, 4, 5, and 10 the circular furnace is shown in connection with the salt pan,
the flues ramnifying thereunder. After leaving the salt pan the flues L (see
Figures 10 and 11) open out into a series of flues L' which are spaced with
drying ditches M, the flues and ditches being covered with a floor over which
there is a drying stove N. The flues L' lead into the flue L¹, from whence they
pass through the pipe L to the smoke condensing apparatus P hereafter described.
The pipe L is led through the brine gutter or trough O, which conveys the brine
to the salt pan.
As an alternative to the circular furnace I form the furnace of straight tunnels
or flues, and I provide therein a series of rotating blades or screws, preferably of
fire brick b (see Figures 7 and 8). The upper portion of the blades 6 are exposed
to the fuel as the screws revolve, which revolving motion is imparted to them by
suitable gearing.
The object aimed at by the circular or the screw construction of furnace is the
working of the incandescent fuel away from the supply of fresh or green fuel, so
that the gases and smoke have to pass over the incandescent or burning fuel and
are thereby consumed.
Under the second part (see Figures 13, 14, 15, and 16) I construct the boiler Q
with a vertical cylindrical shell, having a dome top. The interior of the boiler Q
is constructed of concentric chambers, R being the water spaces, and S being the
heating spaces or flues. The boiler is mounted over the circular flue A, similar to
that described under the first part, provided with a rotating fire grate, the furnace
crown being formed by the flue a of the boiler, J being the firing door and T the
outlet to the chimney or to the smoke condenser P. The sides of the interior
water spaces are perforated so that the water has free circulation therethrough,
the shells being provided with suitable doors for access and cleaning. The current
of combustion and the gases is indicated by the arrows in Figures 14 and 16,
namely, the current or draught after passing round the flue 1 is arrested by a
damper and passes through a side flue into the flue 2; after passing round flue 2-it
is again arrested by a damper and passes through an up flue into flue 3, round

page_text: which it passes, and is again arrested by a damper and passes through a side flue
into flue 4 round which it passes, and is again arrested by a damper and is led
through the flue T to the chimney. The alternative arrangement of Figures 13
and 14, shown at Figures 15 and 16, will be understood upon reference to the
Drawings. In Figure 17 a circular brewers' pan R with. a rotating stirrer R' is
shown over the flue A.
Under the third part salt pans according to my Invention are constructed as
shown at U, Figures 3 and 9, namely, the pan U may be about fifty feet in length
by twelve feet in width, and of the usual depth with slanting ends, as shown at
Figure 3; and straight sides, as shown at Figure 9.. Fitted within the pan U and
running longitudinally therewith I form a wooden covering of planks V, supported
by buoyant pontoons W, of wood or suitable material. The covering or planks V
thus float on the surface of the brine in the pan U. The covering may be con-
veniently made in four widths, leaving a space between them to allow for the
scrapers in manner as shown at Figure 9. The pans may be provided with funnels
or shafts to lead away the steam or vapour.
Under the fourth part I construct a raking or scraping appliance for the salt
pans of a flat board, or iron, or steel plate d (see Figures 3 and 9). The board d
is provided with a stale or handle e, which runs in the space formed between the
planking V (see Figure 9). The handle e is provided with two wheels f, which
support the scraper and run on the planks V. The operator in using the scrapers
walks on the covering planks V, which, are strong enough to support him and
scrapes the salt lengthways of the pan, namely, up to the part U' instead of
crossways as at present practised. The salt is thus scraped as concentrated into the
coolest part of the pan and up against the brine supply through the cock g, which
brine supply tends to wash the salt. After concentration the salt is removed from
the pan and formed into blocks, or loose and placed in the trucks h, such as shown
at Figure 10. The trucks are then wheeled down an incline, pass through the
- ditches. M, and from thence up an incline and into the sho N, as shown at
Figures 10 and 11.
Under the fifth part I construct an apparatus such as illustrated at P, Figures 1
and 12, to which the smoke and noxious gases from the furnaces of the salt pans
or boilers is led, the apparatus being also suitable for condensing the noxious gases
of chemical works. The apparatus consists of a conical tower P constructed of any
suitable material. The interior of the tower is provided with shelves or trays,
which divide the tower into alternate cisterns i and condensing chambers k. The
central shaft is also provided for supplying ventilation. The chambers k com-
municate with each other through the uptakes m, such uptakes being provided
with dash plates n'and the uptakes m, open at the bottom into the cisterns i as
well as into the chambers k. The smoke and gases enter the lowest condensing
chamber k, and pass up to the higher chambers k through the uptakes m. A
stream of water is led into the higher cistern from whence it showers down into
the top chamber k. The water then passes through the top uptake m and is
diverted by the dash plates n into the next cistern i, and so on to the bottom of
the tower. In case there is not sufficient natural draught in the tower an
artificial draught may be obtained by the use of a fan or blower, placed between
the flue or flues in the furnace and the bottom of the condensing tower.
The water after falling into the lower chamber k is led away through the
outlet pipe p.
Under the sixth part, when the salt has been concentrated in the pans under the &
third part and dried in lumps in the stoves as described, I granulate the lump salt
by means of the apparatus illustrated at Figures 18 and 19. This apparatus
consists of a reciprocating frame 5, operated by the crank 6 through the connecting
rod 7. The frame 5 carries a duplex system of horizontal blades or plates 8.
These plates have their edges serrated or saw toothed. The blocks of salt are 5
conducted down the shoots 9 by the rotation of the spike rollers 10, and the
rubbing or friction of the serrated edges of the plates 8 caused by the up and down

page_text: movement thereof against the lump salt, separates and breaks the crystals and
grains of salt. After being granulated the salt passes into the hopper 11 from
which it is sacked or passed to the apparatus under the seventh part.
Under the seventh part I pass the salt that has been granulated in the apparatus
under the sixth part into the apparatus shown in sectional elevation at Figure 20,
which consists of the circular box 12 provided with a series of fixed trays 13
placed one over the other, the bottoms of which are formed of wire, network, silk,
or gauze of different meshes, the coarset mesh being on the top tray. Within the
trays I provide the revolving brushes 14 which brush the salt through the trays
and delivers the different grades to side spouts from each tray; the upper tray is
preferably considerably coarser in its mesh, and serves to remove the coarser
particles of panscale and other impurities.
Having now described my Invention, and shown how the same may be put into
practical operation, I claim,-
Under the first part,—
First. The particular arrangement and construction of circular travelling
furnace, as herein described and shown at Figures 1, 2, and 3 of the Drawings
hereto annexed.
Second. The particular arrangement and construction of circular travelling
furnace, as herein described and shown at Figure 6 of the Drawings hereto
annexed.
Third. The particular arrangement and construction of continuous screw furnace
for salt pans, as herein described and shown at Figures 7 and 8 of the Drawings
hereto annexed.
Under the second part,―
First. The arrangement and construction of steam boiler and circular furnace,
as herein described and shown at Figures 13 and 14 of the Drawings hereto
annexed.
Second. The arrangement and construction of steam boiler and circular furnace,
as herein described and shown at Figures 15 and 16 of the Drawings hereto
annexed.
Third. The arrangement of brewer's pan, herein described and shown at Figure 17
of the Drawings hereto annexed.
Under the third part,-
First. Constructing pans for concentrating brine with inclined ends and straight
sides, so that the concentrated salt may be scraped the lengthways of the pan,
substantially as herein described and shown in the Drawings for the purposes set
forth.
Second. Providing salt pans with a floating covering, substantially as herein
described and shown at Figures 3 and 9 of the Drawings hereto annexed.
Under the fourth part,—
The arrangement and construction of the scraping appliances, substantially as
herein described and shown at Figures 3 and 9 of the Drawings hereto annexed.
Under the fifth part,―
The arrangement and construction of the apparatus P for condensing smoke and
noxious gases, substantially as herein described and shown in Figures 10 and 12 of
the Drawings hereto annexed.
Under the sixth part,-
The arrangement and construction of apparatus for granulating lump salt,
substantially as herein described and shown at Figures 18 and 19 of the Drawings
hereto annexed.
Under the seventh part,-
The arrangement and construction of apparatus for dressing and sifting salt,'
substantially as herein described and shown at Figure 20 of the Drawings hereto
annexed.
Lastly, I claim,-
The general arranged system of furnaces, salt pans and appliances, stoves and

page_text: smoke condensing apparatus herein described and shown at Figures 10, 11, and 12,
of the Drawings hereto annexed.
In witness whereof, I, the said Thomas Barrow, have hereunto set my
hand and seal, this Eighteenth day of February, in the year of our Lord
One thousand eight hundred and eighty two.
RWAUULA
BADDAM