IMPROVE- MENTS IN THE MANUFACTURE OF PLASTER OF PARIS, LAMP BLACK, AND COKE
Year: 1846

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, PARFAIT
GROUT, of Rouen, in the Kingdom of France, and late of Leicester Street,
Leicester Square, in the County of Middlesex, Doctor in Medicine, send
greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her.
Royal Letters Patent under the Great Seal of Great Britain, bearing date at
Westminster, the Eleventh day of March, in the ninth year of Her reign,
did, for Herself, Her heirs, and successors, give and grant unto me, the said
Parfait Grout, my exors, adiñiors, and assigns, Her especial licence, full
power, sole privilege and authority, that I, the said Parfait Grout, my
exors, admors, and assigns, or such others as I, the said Parfait Grout, my
exors, admors, 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 "IMPROVE-
MENTS IN THE MANUFACTURE OF PLASTER OF PARIS, LAMP BLACK, AND COKE;"
in which said Letters Patent is contained a proviso that I, the said Parfait
Grout, shall cause a particular description of the nature of my said Invention,
and in what manner the same is to be performed, to be inrolled in Her

page_text: as in and by the same, reference being thereunto had, will more fully and at
large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Parfait Grout, do hereby declare that the nature of my said Invention, and the
manner in which the same is to be performed, are fully described and ascer-
tained in and by the following statement thereof, reference being had to the
Drawings hereunto annexed, and to the figures and letters marked thereon,
that is to say:-
DESCRIPTION OF THE DRAWINGS.
No. 1, plan of the kilns for coke, plaster of Paris, and of the heated
chamber. The black lines shew the ground plan of the kilns for coke, the
red lines shew the kilns for plaster of Paris, and the heated chamber, which
are placed over the kilns for coke. No. 2, section of the line X, Z, of the
plan No. 1.
No. 3, section of the line C, D, of the same plan. No. 4,
section of the line P, Q, of the same place.
Explanation of the letters marked in the plan No. 1. A, A¹, coke
kilns. A", vault forming the lower floor of the heated chamber. B, B', kilns
(or reverberating furnaces) for baking or burning the plaster. B", heated
chamber made of brick for baking or burning the plaster. c, c, c, c¹, three
close chambers, where the lamp black is deposited. d, d', d", chimneys
through which the chrystallized water of the stone from which the plaster is
made escapes in vapour. E, E', chimneys which conduct the smoke from the
coke kilns A, A', into the closed chambers c, c, c, c¹, after the same smoke has
passed through the chimneys 8, 8. F, F, F, F¹, four air pipes to the coke
kilns, which serve to keep up the combustion, and prevent the coke adhering
to the bottom of the kilns. These air pipes are placed in each kiln one above
the other, two being on a line with the floor and two on a line with the
springing of the vault. ff.f.ƒ ƒ`ƒ³‚ƒ`, ƒ³‚ƒ", f", f", f", exterior and
interior openings or conduits for the hot-air currents, which serve to expel the
chrystallized water contained in the stone for making plaster through the
chimneys d, d', d". G, G, G¹, G₁,. chimneys for drawing up the smoke.
II, H', bags made of coarse linen or canvass with a rough and shaggy surface,
distended at top and bottom by iron hoops, and fastened at the open ends to
the floor, and at the closed ends suspended by small chains passing through
two pullies. I, I, I, I, circular inclosure or space (contrived round the heated
chamber) in which circulate the heat, flame, smoke, and all the products of

page_text: combustion. J, J', conduits through which the heat, flame, smoke, and other
products of combustion pass under the vault A", which serves as a floor for the
heated chamber. K, K¹, moveable iron plates or traps covered with fire tiles,
which form a floor to the upper part of the openings L, L', by means of
which the orifices 0, 0, 0, 0, are opened and shut. L, L', openings;
M, M', other openings made in the thickness of the vaults of each coke kiln,
and which afford access to open and shut the capped flues S, S, S, S, S, and
S¹, S¹, S¹, S¹, S. N, N, N, N, N', N', N', N³, cast-iron plates arranged above
the extrados of the vaults of the two coke kilns, and supported at a distance
of a few inches from the summit of the vaults by haunch piers or circular
supports of masonry or fire brick. 0, 0, 0, 0', openings through which the
heat, flame, smoke, and all the products of combustion circulate round the
heated chamber B", in the circular inclosure or space I, I, I, I. P, P,
moveable cast-iron plates cased with fire brick to close or open the conduits
J, J. These plates move in grooves by means of handles with which they
are furnished. T, T¹, doors of coke kiln. u, u, u, u, u, u, u', u', u¹. u¹, u', u',
haunch piers or circular supports of fire brick, which allow the free
passage of
the exterior air let in by the openings or conduits fƒƒƒƒ^ƒ‹ƒ^ƒ³, and
allow the air to heat itself, and pass through the openings or conduits
ƒ› ƒ ƒ ƒ ƒ³‚‹ƒ³‚‹ƒ, f, into the reverberating furnaces B, B¹. V, V¹, cast-iron
doors for the reverberating furnaces B, B'. V", exterior cast-iron door to
heated chamber B". V, a door of stone of plaster of Paris worked in
masonry in the interior circular wall of the heated chamber B". Y, Y',
wrought-iron dampers, with long handles, used for opening and shutting the
interior chimneys 8, 81. 8, 8¹, two exterior chimneys in the circular inclosure
or space I, I, I, I, which allow of the heat, flame, smoke, and all the products
of combustion received in the space I, I, I, I, to slowly pass into the extrados
of the vault of the heated chamber. 10, 10, a ring of masonry round the top
of the circular inclosure or space I, I, I, I, to prevent the heat, flame, smoke,
and all the products of combustion from passing into the chimnies E, E', and
to force them through the lower openings of the two interior chimnies 8, 8¹.
101, 101, a second ring, with openings, for the same purpose.
parts
Explanatory statement of manipulations and operations of the several
of the apparatus. Before commencing operations it is necessary to know that
both coke kilns must not be heated at the same time, but one after the other.
One half only of the apparatus is set at work at the commencement. The other:
half is not set at work. Supposing I wish to commence working the right
side of the apparatus, my operations would be as follows:-I charge the
coke kiln A with coal to within five or six inches of the springing of the arch

page_text: or vault of the kiln. The reverberating furnace B and the heated chamber B
I also charge with stone for making plaster, but so as to leave access to the
openings of the capped flues S, S, S, S, S, of the coke kiln A, which I had
previously closed. I then fill up close with the same stone the doorway or
opening through the circular wall of the heated chamber V; and I well
cover with mortar of plaster of Paris the whole doorway or opening, so as to
exclude the air, and to prevent the flame and smoke from passing into the
heated chamber. I then close the iron doors V, V". I shut the opening J by
sliding into it the iron plate P by means of the iron bandle with which it is
furnished. I shut with the dampers Y the opening of the interior and invi-
sible chimney 81, but which is placed above the opening O, O. Through the
openings L' and traps K', I shut with fire plugs the openings 01, 01, but I
take care not to shut the opening of the second interior chimney 8. I then
shut the traps K and K', which I lute over with clay. I then shut with an
iron plate the chimney E¹ of the chamber for lamp black, as well as the chim-
ney G¹ for attracting the smoke by means of a groove, as I have explained in
the plan No. 1, whilst on the other side I keep open the chimney E and the
opening G. These precautions taken, I open the air pipes F, F, of the coke
kiln A, and I then set fire to the coal contained in this kiln. The flame,
smoke, a portion of the heat, and all the products of the combustion pass
through the conduit J, under the vault A", and by the opening O, O, into the
circular inclosure or space I, I, I, I, round the heated chamber, and are there
retained by the rings of masonry 101, 101, 10, 10; but the draught of the
chimney E soon carries off the flame, smoke, a portion of heat, and all the
other products of combustion, by means of the tube of the other interior
chimney 8, the opening of which is placed above but at an intermediate dis:
tance between the orifices O¹, 0¹, and so introduces the flame, smoke, portions
of heat, and products of combustion into the (extrados) or exterior curve of
the vault, and thence conducts them into the chambers for lamp black C, C,
C, C, where the flame cannot reach. The openings G, G, keep up the draught,
and give a passage to the different gaseous substances produced by the com-
bustion, while the coarse linen or canvas bag H retains the lamp black, of
which a portion has been already deposited upon the walls of the lamp black
chambers C, C, C, covered or lined over with coarse canvass. So soon as the
entire mass of coal placed in the coke kiln A is in a perfect state of combus-
tion, I shut the lower air pipe F, to prevent the coke becoming cinder or
diminishing. Whilst these operations are going on, the air pipes of the
opening for the passage of the hot-air currents f, f, fff", f", f", are
constantly kept open, and the chrystallized water which is contained in the

page_text: stone for making plaster, being reduced into vapour, is forced to issue by the
chimneys d, d". It will be necessary frequently to shake the canvass bag H.
by means of the cord to which it is suspended, in order to cause the lamp
black to fall, and allow the current of air to pass, so as to keep up the fire.
When this operation has been carried on for a certain time, and the plaster is
almost baked or burnt, and no more smoke issues from the coke kiln A, I
take a long iron rod with a hook at one end, introducing it through the
opening M and the door V, previously opened for that purpose. I remove
the plugs which closed the capped flues S, S, S, S, S, shutting the conduit J.
At this stage of operation I finish by means of the radiant heat of the red-
hot coal the baking or burning of the plaster in the reverberating furnace B,
and I leave the coke to complete itself, it requiring almost as much time to
effect its completion as I have already spent in baking or burning the plaster.
To accomplish this, when I think the plaster in the reverberating furnace. B
perfectly baked or burned, I replace the plugs in the capped flues by the same
means I have already indicated, and there leave them until the coke is per-
fectly made. Whilst the process of completing the coke is thus going on, I
empty the reverberating furnace B, and charge it afresh with stone for
making plaster of Paris; but I do not touch the heated chamber B", which
requires to receive the heat of the other coke kiln A', in order that the stone
for plaster which it contains should be baked or burned. I proceed with the.
apparatus of the left side in the same manner as I have already described
with regard to the right side; that is to say, I charge with stone for making
plaster of Paris the reverberating furnace B¹, and the kiln (A') for making
coke with coal. I open the conduit J' by withdrawing the iron plate P. I also
close the orifices O, O, and I unstop the interior chimney 8¹, which is placed
above or over them, by withdrawing the damper. I then, through the opening
L', unstop the openings O¹, O', and I push in the damper Y', in order to shut
the chimney 8. The traps K, K', are then replaced, and luted with clay. I
then proceed to the chamber for making lamp black, and I remove the
cast-iron plate from the chimney E', and I stop the chimney E'.
I again
close the chimnies G, G, and I open those G¹, G'.
kiln A', and I follow the same mode of operations
with regard to the right side of the apparatus.
ceased to emit flame and smoke, the plaster in
entirely baked or burned, and needs no further heat. I then proceed to open
the capped flues S¹, S¹, S¹, S¹, S¹, with the long iron rod hooked at one end, as
before described, and introduced successively through the opening M¹ and the
door V', and shutting the conduit J' by means of the iron plate P. The baking.
I then set fire to the coke
I have already described
When the coke kiln A' has
the heated chamber B" is

page_text: or burning of the plaster in the reverberating furnace B' requiring to be com-
pleted by means of the rays of heat produced from the coke kiln A', I replace
the plugs in the capped flues, and I leave the coke to be completely made.
During this time I discharge the heated chamber B" and the reverberating
furnace B', and I then recharge them immediately with fresh stone for making
plaster. At this period the coke in the first coke kiln A is completely made.
I withdraw it, and I recharge it with fresh coal; and as I had already taken
care to empty and recharge the reverberating furnace B, it is only necessary,
first, to withdraw the iron plate P₁, and to close the openings 0, 0¹;
secondly, to draw out the damper Y', in order to open the chimney 8; thirdly,
to shut the opening L', and to lute or close with clay the iron plate K';
fourthly, to proceed to the opening L, already unclosed, and to unstop the
openings O, O, then to shut the opening L, and to lute or close carefully with
clay the trap K; fifthly, to push in the damper Y in order to close the
chimney 81; sixthly, to unstop the chimney E, and to stop the chimney E';
seventhly, to open the groove G after having closed the grove G¹; eighthly,
to light the fire in the coke kiln A, and recommence the series of operations
before explained. By having the heated chamber B" made of cast or wrought
iron instead of brick, as before described, and which cast or wrought iron
chamber I am entitled to adopt as preferable to the brick one, the heat
produced by one coke kiln will be sufficient to bake or burn the stone con-
tained in the heated chamber B" and reverberating furnace B to plaster
simultaneously. The course I follow when I use a cast or wrought iron
heated chamber is, I charge the reverberating furnaces B and B' and the
heated chamber B, as before described, with stone; I then set fire to the coke
kiln A, by means of the heat of which I bake or burn the stone in the
reverberating furnace B and the heated chamber B", simultaneously to plaster;
I then withdraw the plaster from the reverberating furnace B and the heated
chamber B, recharging with stone the heated chamber B"; I then set fire
to the coke kiln A', by means of the heat of which I bake or burn the stone
in the reverberating furnace B' and the heated chamber B" simultaneously to
plaster.
The advantages of my mode of manufacturing plaster of Paris are:-
First, a superior quality, inasmuch as the smoke or lamp black flame and the
gaseous products of the combustion of the coal do not come in contact with,
blacken, or affect the calcareous salt; second, a great saving, inasmuch as
the burning or baking of my plaster costs nothing, as I receive in coke the
same value of the coal employed, and I also obtain twenty per cent. of the
value of the coal in lamp black. In manufacturing coke, I produce a superior

page_text: quality by reason of the proportions and forms of my kilns, and of the pre-
cautions I employ for their ventilation, which gives me an article in all its
parts alike and perfectly purified. The proportions of my coke kilns are
calculated with reference to the capacity of my kilns for burning plaster. By
means of the precautions employed, and described in the plans for ventilating
the coke kilns and the vaults upon which they are constructed, I obtain coke
equally burned and perfectly free from all impure matter. I do not claim to
be the Inventor of the ordinary means employed in making coke and lamp
black, nor do I confine myself to the precise details herein given; so long as the
character of the Invention be retained; but what I claim is, the mode of
manufacturing plaster in the way described; that is to say, I take or burn
stone to plaster of Paris, at the same time that I make coke and lamp black.
This plaster is of a pure white color, is equally and perfectly baked or burned,
and consequently possesses all the qualities appertaining to good plaster.
In witness whereof, I, the said Parfait Grout, have hereunto set my
hand and seal, this Fifth day of September, in the year of our Lord
One thousand eight hundred and forty-six.
Taken and acknowledged by Parfait
Grout (party hereto), at Rouen, in
the Kingdom of France, this Fifth
day of September 1846, before me,
PARFAIT (L.S.) GROUT.
DEA British Vice Consul
In the matter of the Patent of Parfait Grout.
. I, Victor Delassaux, of Leicester Sreet, Leicester Square, in the County of
Middlesex, Architect, make oath and say, that I did see Parfait Grout, of
Rouen, in the Kingdom of France, Doctor in Medicine, sign and seal the Spe-
cification or Parchment Writing hereunto annexed, marked with the letter (A),
and that the signature Parfait Grout subscribed at the foot of the said Specifi-
cation is of the proper handwriting of the said Parfait Grout; and I further
make oath and say, that I was also present and did see the said Parfait Grout

page_text: acknowledge the said Specification before Edouard Decaën, Her Majesty's
Vice-Consul at Rouen aforesaid, and that the signature E. Decaen subscribed
to the said acknowledgment, and the words "British Vice-Consul," written
underneath the said signature, are in the proper handwriting of the said
Edouard Decaën, and that he held the said office of British Vice-Consul at
the time of his taking the said acknowledgment.