IMPROVEMENTS IN THE MANUFACTURE OF SALT
Year: 1844

page_text: AFE
THESE TREDERIC
GREENSHIELDS, of Oxford, Architect, send greeting.
HOMAS
WHEREAS Her present most Excellent Majesty Queen Victoria, by
Her Letters Patent under the Great Seal of Great Britain, bearing date
at Westminster, the Sixth day of August, in the eighth year of Her reign,
did, for Herself, Iler heirs and successors, give and grant unto me, the
said Thomas Greenshields, Her especial licence, full power, sole privilege
and authority, that I, the said Thomas Greenshields, my exors, adñiors, and
assigns, or such others as I, the said Thomas Greenshields, my exors,
adiñors, or assigns, should at any time agree with, and no others, from
time to time and at all times during the term of years therein expressed,
should and lawfully might make, use, exercise, and vend, within England,
Wales, and the Town of Berwick-upon-Tweed, my Invention of "IMPROVEMENTS
IN THE MANUFACTURE OF SALT;" in which said Letters Patent is contained a
proviso that I, the said Thomas Greenshields, shall cause a particular descrip-
tion of the nature of my said Invention, and in what manner the same is to
be performed, to be inrolled in Iler Majesty's High Court of Chancery
within six calendar months next and immediately after the date of the said
in part recited Letters Patent, as in and by the same, reference being there-
unto had, will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso. I, the said
Thomas Greenshields, do hereby declare that the nature of my said Invention,
and in what manner the same is to be performed, are fully described and ascer-
tained in and by the following statement thereof, reference being had to the

page_text: My Invention relates,--
Firstly, to a method of withdrawing the steam (from a covering forming a
chamber to collect it) that rises from the brine in making salt to accelerate
the evaporation.
Secondly, to a method of using the steam so withdrawn to make salt or heat
brine as may be required.
And thirdly, to a method of preventing currents of cold air from entering
between the bottom of the pan and its seat or bearing on the outside wall; that
is to say, the heat applied to the pan bottom to make salt causes an expan-
sion, the weight of heated brine depresses the centre of the pan, causing the
sides to rise from its seat in several places, leaving considerable spaces through
which the cold air rushes, not only acting prejudicially to the durability of
the pan, but also effects the arrangements for insuring a proper combus-
tion of the fuel and prevents the possibility of maintaining a regular tempera-
ture so essential for obtaining the best results.
Having now described the nature of my Invention, I will now proceed to
shew the manner in which the same may be performed by the following
description, reference being had to the Drawings annexed. The same letters
denote the same parts throughout the Drawings.
DESCRIPTION OF THE DRAWINGS.
No. 1, portion of the ground floor of a salt-pan house. A, front pan, made
in the usual manner for making stoved or fine salt. B, back pan, made in
the usual manner for making common salt. C, C, taps for supplying the
pans with brine, connected with pipes leading to the reservoir or tanks.
No. 2, portion of the first story, being over the portion shewn by the
Drawing No. 1. D, D, pans for making common salt, which I prefer made
of elm plank, see description to the Drawing No. 9. E, fan-blowing machine
(see description to the Drawings Nos. 6, 7, and 8, for withdrawing the steam
from the chamber J of the pan A, as fast as it is generated, and forcing it
into the steam pipe F, under pressure, to heat the brine in the pan D, to make
common or other description of salt having large crystals. F, F, steam pipe
for receiving the steam from the blowing machine E, constructed of rolled
sheet iron one quarter of an inch thick, and rivetted in the same way as salt
pans usually are; for section on a larger scale, see Drawing No. 9. G, escape
pipe, connected with the opening left in the end of the steam pipe F, by means
of a flanch joint, having a tap 9, for regulating the escape of the steam, the

page_text: heat communicated to the brine through the steam pipe F being greatest
when the opening or way in the tap g is nearly closed, and the heat can be
further augmented by decreasing the size of the driving pulley Q, on the shaft
o, o, of the blowing machine E, see description to Drawing No. 7. The
steam that escapes can be conducted in iron steam pipes in a similar manner
as shewn in the pan D for making salt or for heating brine to supply the
pans A, B, D. H pipes to convey away the water from the condensed steam,
having a descending pipe connected that must descend to the ground floor, and
turn up four feet, with a tap on the end to regulate the escape of the condensed
>water, to retain sufficient water in the pipe H to prevent the escape of the
steam, as is well understood; the waste water may be collected in a suitable
tub for use, or conveyed into the nearest drain. I, I, portions of the pan
removed, two feet long, and the whole depth of the side, and the opening
closed with sheet lead in a curved form, thus
"
well and
securely nailed with copper nails (the heads leaded) to the sides and bottom of
the pan to form a flexible piece to allow for the expansion and contraction of
all the pipes passing through the sides of the
pan.
No. 3, section of the line 1, 2, on the Drawings No. 1 and 2, shewing
the covering of the pans to form chambers to collect the steam, and the
blowing machine E connected to withdraw the steam. J covering to the
pan A, constructed with yellow pine timber and boards, see also Drawing
No. 4 and 5, j, j j, &c., being apertures in the sides four feet long and three
inches wide to admit the handle of the rake used in collecting the salt, and
draw it to the side in the usual manner; these apertures are closed by doors
when not in use, that is to say, one only at a time need be opened. K, covering
to the back pan B, i, i, i, &c., being folding doors for drawing the common
salt made in the pan B, closed when not in use. , an clm pipe to connect
the chamber K with the chamber J, regulated by a slide, and that completely
shuts the opening in the pipe when the salt is being drawn from the pan B.
L, driving wheel, connected by the driving band I, I, to the driving pulley Q, to
drive the wings or fans s, s, of the blowing machine E. The driving
wheel L is connected by shafting and gearing to a steam engine to drive it.
No. 4, section on the line 3*, 4*, on the Drawing Nos. 1 and 2, shewing
the mode of constructing the covering to form the chamber to collect the
steam, also the posts, beams, and framing to support the elm joists m, m, to
carry the pans D, D.
x, a, gutters made of tinned copper, to collect the con-
densed water from the roof forming the covering to the pans A, B, connected
with similar pipes, as described by letter H, Drawing 2.

page_text: No. 5, end view of the pan A, shewing the mode of connecting the blowing
machine E, with the covering J, to the pan A, and connecting the blowing
machine E with the pans D, D, sec also Drawing. No. 3, the dotted line
shewing the pipe q for taking the condensed water from the body of the
machine E to the gutter a.
No. 6, side elevation of the blowing machine E to a larger scale. M, cast-
iron pipes connecting the centre opening in the side of the machine with the
chamber J, see also Drawing No. 7. N, the sides of the machine E, made of
east iron five eighths of an inch thick, having a groove n, m, n, to receive a
rim of rolled sheet iron, a quarter of an inch thick and nine inches wide, the
rim being secured to the sides by screw bolts passing through each side and
across the back of the rim, having thin leather and white lead round the edge
of the rim, to make it air-tight in the groove.
No. 7, section shewing the internal construction of the blowing machine E.
C, O, stuffing boxes for the shaft o, o, to pass through steam-tight to carry
the wings or fans s, s. P, carriages with brasses to carry the shaft o*, o*.
P, p, ledge and bracket to carry the carriages P. Q, driving pulley keyed
upon the shaft to drive the wings or fans &, s; this pulley can be readily
removed by withdrawing the key, and a larger or smaller one keyed upon the
shaft to regulate the speed of the fans s, s, as may be required in conjunction
with the tap g, see description to Drawing No. 2. q a pipe to convey the
water from the condensed steam in the machine E to the gutter a, as shewn
in Drawing No. 5.
No. 8, side elevation, shewing the number of wings or fans. R, cast-iron
centre and arms, the centre to be keyed on the shaft o*, o*, and the sheet-
iron wings s, s, are secured by proper screw bolts to the cast-iron arms.
No. 9, section on a larger scale, shewing the section of a steam pipe F,
supported on r, elm brackets cut to the sweep of the steam pipe, and also
shewing the construction of the elm pan D. m, m, elm joists to carry the
pan D to be cross strutted every two feet along their length. t, the bottom,
v, v, being cross tongues of beech let into plough grooves. y, the side of the
pan tongued into the bottom of the pan. a, a, a, pins or pegs made from
black sally poles, one inch and a quarter round, and driven tight into the
holes accurately bored with a 1 auger. The side y is to be secured every
three feet in length with a screw bolt, and passing through the side of the
pan through the bottom and screwed up on the under side of the bottom.
No. 10, section to a larger scale, shewing the third part of my improvements.
A, front pan; 5, a cast-iron trough or gutter, having flange joints to connect
them. 6, a piece of rolled pan-plate, rivetted to the side of the pau A, and;

page_text: passing into the trough 5. 7, a lid or flap of half inch yellow pine hinged to
the piece 6, and resting on the edge of 5, that rises and falls with the pan and
prevents the brine or salt from entering the trough 5, where it would soon
crystallize and impede the action of the piece 6. 8, water, shewn by the blue
color, into which the piece 6 enters and forms what is termed the water lute.
9, the walls supporting the bottom of the pan near the outer edge. 10, a brick
let into the wall 9, and set in cement to carry the trough 5.
Having thus described the nature of my Invention, and the best method of
applying the same, I will now describe the mode of working. If the object is
only to make fine salt, or what is called butter salt, I prefer working with
eight inches of brine in the pan, and running in constantly heated brine from
the back pan equal to quantity evaporated. The bottom of the covering to
the
pan may be six inches above the surface of the brine, and the steam that
is withdrawn may be passed through brine in iron pipes to heat it to supply
the back pan. I prefer drawing the salt from the pan often, if it is required
light (every two hours), and not so often if it is required heavy (every three
hours), and thus constantly continue the operation for five days, or until the
pan requires picking. If the object is to make fine salt, and afterwards use
the steam for making common salt, I prefer working with eight inches of
brine in the pan, and running in cold brine from the supply tap constantly to
supply the quantity evaporated. The bottom of the covering to the pan must
be kept from one to two inches below the surface of the brine, and the blowing
machine regulated to withdraw the steam as fast as it is generated, to relieve
the surface of the brine from pressure; the withdrawn steam to be forced
through the iron steam pipes, as before described; and I prefer drawing the
salt, as herein-before described, as it may be required light or heavy. I would
further observe that the steam from the pans making common salt may be col-
lected in the same manner as described to the pan B, having a pipe from cach
covering leading to and communicating with a chamber, on which is fixed one
blowing machine, by the action of which the evaporation will be accelerated
and the withdrawn steam used, as before described.
Having thus described the nature of my Invention, and the best means I
am acquainted with for performing the same, I would wish it to be understood
that I do not confine myself to the precise details herein stated, provided the
peculiar character of either part of my Invention be retained. I wish it to
be understood that I make no claim to having discovered iron or wooden pans,
or the covering the same, or to the iron steam pipe, the same having been
used before. What I do claim is,-

page_text: Firstly, the method of withdrawing steam from the covering to salt pans, to
accelerate evaporation.
Secondly, I claim the method of using the steam so withdrawn for heating
brine and making salt, as described.
Thirdly, I claim the method of preventing currents of cold air from entering
between the bottom of the pan and the wall, as described.
In witness whereof, I, the said Thomas Greenshields, have hereunto set
my hand and seal, this Thirty-first day of January, in the year of our
Lord One thousand eight hundred and forty-five.