CERTAIN IMPROVEMENTS IN APPARATUS FOR GENERATING AND PURIFYING GAS FOR THE PURPOSES OF ILLUMINATION
Year: 1836

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAN
BARNETT, of Brighton, in the County of Sussex, Iron Founder, send greeting.
WHEREAS His most Excellent Majesty King William the Fourth, by His
Letters Patent under the Great Seal of Great Britain, bearing date at West-
minster, the Twenty-second day of June, in the sixth year of His reign,
did give and grant unto me, the said William Barnett, my exors, admors,
and assigns, His special licence, full power, sole privilege and authority, that
I, the said William Barnett, my exors, adñiors, and assigns, 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 "CERTAIN IMPROVEMENTS IN APPARATUS FOR GENERATING
AND PURIFYING GAS FOR THE PURPOSES OF ILLUMINATION;" in which Letters
Patent there is contained a proviso obliging me, the said William Barnett,
under my hand and seal, to cause a particular description of the nature of
my said Invention, and in what manner the same is to be performed, to be
enrolled in His Majesty's High Court of Chancery within six calendar months
next immediately after the date of the said recited Letters Patent, as in
and by the same (relation being thereunto had) will more fully and at large
appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
William Barnett, do hereby declare that my said Invention of "Certain
Improvements in Apparatus for Generating and Purifying Gas for the Pur-
poses of Illumination" is ascertained and described by these Presents, and by,

page_text: :
the Drawings hereunto annexed, and herein referred to by way of illustration
and example.
One part of my said Invention of Certain Improvements in Apparatus
for Generating and Purifying Gas for the Purposes of Illumination" is an
improved method of constructing the roof or arch of the oven or outer
chamber in which gas retorts are placed or set, and it consists in forming
such roof or arch in parts or sections, consisting of oblong cases or troughs
or frames of iron or other proper substance, to contain and surround the
bricks and other materials to be used in the formation of such roof or arch,
and in which troughs or frames such materials are compressed by plates of
iron or slides provided for that purpose, and are otherwise secured so as to
render the entire mass removeable without destroying or disturbing its parts.
The manner of constructing these troughs or frames is explained by the
Drawings hereto annexed, Figures 4, 5, 6, and 7, and by the references thereto
herein-after contained.
Another part of my I said Invention consists in an improved construction of
gas retorts. By the usual method of constructing gas retorts in one cylin-
drical or other plate of metal, the destruction of a part of a retort renders
the whole unfit for use. My improvement is designed to obviate this by
constructing such retorts in two parts, so flanched and cemented together that
when either part is destroyed it may be disunited, and another be substituted
without occasioning the loss of the whole. The construction of gas retorts
upon this improved formation is shewn by Figures 8 and 9, and explained
by the references thereto herein-after contained.
Another part of my said Invention consists in an improved apparatus for
the extrication and purification of inflammable gas produced by the distillation
of coal or other suitable substance, by means whereof I am enabled to
supply the gas. retort with successive half-charges of coal, to distribute it in
thin layers or ridges upon the interior surface of the bottom of the retort,-and-
afterwards to discharge it therefrom when completely carbonized without
admitting atmospheric air within, or permitting the escape of gas from the
retort, and also without interrupting the continuous process of distillation
during those processes. I am also enabled to compel the vapours evolved
from the coals newly introduced into the retort, to pass through steam over
the surface of the burning coals or coke in a more advanced state of
carbonization, by which means the tar and other carbonaceous products of
the earlier and incomplete distillation of the coals are precipitated upon 'the
heated surface beneath, where they are again distilled and converted into
elastic vapours. These objects I am enabled to effect by means of a feeder

page_text: to supply the coal, and a box to receive the coke, with proper contrivances
for the shutting off or preventing the escape of gas or the admission of
atmospheric air during their operation; and by an interior apparatus, con-
sisting of what I have herein denominated a "plougher" and "scrapers,"
worked by rods from the outside of the retort, or by other machinery, I
augment the useful, and separate therefrom the baneful gases, which are
discharged from the retort by passing them through a cylinder, which I have
herein denominated a " digester," divided into compartments or chambers,
subjected to the action of heat in all its parts, but in different degrees of
intensity, the chambers being charged or filled with coke, old iron, and limo
or other substances having affinities for and thereby separating, or partially so,
the ammonia, the carbonic acid, sulphuretted hydrogen, and other gases which
are prejudicial to the purposes of illumination from the gases which are
applicable to those purposes. The several parts, the form, construction, and
operation of this apparatus, are shewn and explained by Figures 1 to 3.
and 10 to 31 (inclusive), and by Figure 33 in the annexed Drawings, and
by the references thereto herein-after contained.
The last part of my said Invention consists in an improved modification of
the purifier, by means whereof the lime or other detersive and refining in-,
gredients used for the purpose of purifying gas is constantly charged and
changed without interrupting the process of purification, and without per-
mitting the escape of gas or the admission of atmospheric air. The form and
construction of my improved purifyer is shewn and explained by Figure 32
in the annexed Drawings, and by the references thereto herein-after
contained.
Having now ascertained the nature of my said Invention, I shall proceed
to describe the same, and to shew, by the assistance of the Drawings, in what
manner it is to be performed, first observing that the form, arrangements, and
construction of the several parts of the apparatus may be varied and modified
according to the size of the apparatus, the situation in which it is placed, and
the circumstances governing the same, without at all deviating from my Inven-
tion, as the same is hereby defined.
DESCRIPTION OF THE DRAWINGS.
Figures 4 and 5 are vertical sections of the roof or arch of the oven or
outer chamber constructed on my improved modification. 9, 9, 9, are cast-
iron oblong cases or troughs, containing and preserving the bricks and other
materials with which they are filled, and by which the roof or arch of the

page_text: Figure represents the interior face of one of those troughs when empty,
surrounded by an edge or rim (h), of sufficient depth, or nearly so, to
contain the materials with which it is to be filled, as herein-after described,
and having plates or slides of iron i, i (and Figure 7), placed at or near
cach end thereof, moveable by screws h, k, attached thereto, passing and
working in and through the end rims of the troughs. The troughs may
either be flat or level, as shewn in Figures 4 and 6, or they may be bent or
curved so as when united to form the figure of an arc, as shewn in Figure 5;
but their form is to depend upon that of the retorts to which they are to be
adapted, and their number and dimensions are to be determined by the magni-
tude of the work for which they aro intended to be used. The longitudinal
rims of the trough which are intended to rest on the side walls of the oven
or outer chamber of the apparatus should be sloped or bevelled, so as to describo
a horizontal line, the others being determined by the radius drawn from a
common centre to form proper junctions with each other. This construction
also tends to increase the colierence of the substances with which the troughs
are to be filled, and forms channels for and to preserve the position of the
ends of the interior plates or sliders. The plates or sliders are furnished at
one end with a tongue or projection to fit into but to slide freely within
apertures or grooves formed in the corresponding side rim of tho trough.
These plates or sliders are not made so deep by at least an inch as the
interior of the troughs, in order that a space of that extent may be left
between the lower edge of the sliders and the interior face of the troughs.
The troughs (as at m, Figure 6) are pierced for the reception and passage of
one or more bolts of iron, cross bars or ties, which are used to prevent the
mass of materials when formed from bulging, and which bolts are screwed up
by nuts on the outside of the troughs. The troughs are prepared for use in
the following manner:-First, fill the interior space or cavity of the trough with
a stratum or layer of sand and coke dust or any other suitable slow conductor
of heat, to the depth of one or two inches, and upon this place or build,
with fire-clay cement, a wall or course of brickwork of such solidity as the
extent of the apparatus may require. Then screw up the sliders at each end,
so as to press together and tighten the contained substances as firmly as
may be practicable (without forcing, bulging, or breaking up any portions
thereof), the office of these sliders being to give by pressure a greater co-
Lerence to the said preparation. In like manner the iron bars or ties are
next to be screwed up and tightened, and when that is accomplished fill
up with fire-clay cement the spaces or voids left between the sliders and
the frames, by the screwing in of the former pressing in the cement as

page_text: firmly as possible. Lastly, cover the entire superfices of the mass with a
layer of fire-clay cement to the depth of one or two inches or thereabouts.
The bricks required for the above purpose may be of the common description,
but should be closely cemented together with fire-clay cement, the composition
of which as generally made is well known to consist of fire clay, road dirt
or drift, and iron borings. The relative proportions thereof are not material,
but those usually adopted by me are two parts of fire clay, three parts of
road dirt, and one part of iron borings. When the whole of this preparation
has become dry, it will with the trough form a compact solid mass admitting
of removal, for facilitating which the end rims are externally furnished with
lugs or handles, by which any convenient tackle or power can be applied for
placing the trough in its proper position, or for removing it when necessary.
Roofs or arches upon this modification may be. constructed of various forms,
according to the nature and shape of the retorts employed, or other governing
circumstances; and instead of the troughs above described, a skeleton or
framework, composed of the rims merely, may be substituted and used with
the pressers or sliders, and having double braces or ties. I prefer, however,
the troughs as first described, because they protect the brickwork from outward
injury, and enable me to confine the heat by applying the slow conductor of
caloric before mentioned. But when the skeleton or framework is adopted,
I recommend that a tier or facing of fire bricks be employed in lieu of the
facing of fire-clay cement, before mentioned. When the troughs are placed
upon the side walls of the oven, and in juxta-position with each other, the
longitudinal rims should be joined and incorporated with each other, and
with the side walls, by fire-clay cement, in order to securo them in their
proper positions, and render the junctions air-tight, which object may also
be additionally secured by plates, by luting, or by any other of the usual
methods for effecting such purposes; and whenever it may be found requisite
to open the oven for repairing the retorts or otherwise, these troughs may be
easily detached and removed and afterwards replaced.
Figures 8 and 9 are vertical sections of my improved retort, constructed
in two parts or plates. The bottom plate o at its longitudinal edges is
furnished with a double rim p, p, as shown in the Diagrams, to form a
groove or socket for the reception of the upper plate 9. The depth of
theso rims is about two inches, and between them the longitudinal edges
of the upper plate are to be inserted, and securely fixed by iron or other
proper cement (the composition of which is well known). A perfect joint
can thus be made without the use of bolts or screws, and the plates can be
disunited when either the upper or lower plate has been damaged or destroyed,

page_text: and another plate substituted, without the whole being rendered useless. by the
injury of a part. The upper plate can be made of any figure, the mouth-
pieces being constructed conformably thereto, and fixed by the usual methods,
which are various, and too well known to require description.
Figures 1 and 2 represent perspective views or elevations of the front, back, and
side exteriors of the retort bed and contained apparatus. A, is the hopper; B; the
hopper valve. C, C, the open front mouth-picce of the retort. D, the digester.
E, the eduction pipe. F, the furnace and asbpit. G, G; G, the prepared roof
of the retort resting on the side, front, and back walls of the retort bed. H,
the back mouth-piece of the retort. I, the coke box. J, a pipe arising
from the back mouth-piece H into the cistern K. L, the pipe leading from
the cistern K to the digester D. M, the bent water-pipe. N; internal
apparatus of the digester. Figure 3 is a vertical section of the retort bed: m
represents the point of the introduction of the bent water-pipe Mo is a
section of the retort (the two parts being in connexion). p, the brick arch,
supporting portions of the bottom of the retort: q, qq, bricks placed.at
intervals in the flues of the apparatus, to prevent the bulging of the upper
sides of the retort. 7, 7, are walls enclosing the flues; s; s, s, shew the
course of the flues; and t, t, the side walls. The furnace being. of any
ordinary and proper construction need not be described further than by
observing that the flues in the illustrative Drawings annexed are formed by
the spaces between the interior surface of the roof and the exterior surface of
the retort, and may be carried out either above or below the retort, as circum-
stances or choice inay direct: The various parts of the apparatus; which are
shewn in the above Figures, as they as are hereafter more particularly
described, need not at present to be further explained: The retort, when fixed
in its proper position for operation, rests upon the front and back walls,
Figures 1 and 2, with its mouth-pieces projecting beyond those walls, which
are consequently protected or removed from the influence of the heat from
the furnace. The mouth-pieces are to be flanched to correspond with the plates
or lids, Figures 14 and 15, for closing the same, and which are to be fixed
by bolts or screws, and luting, or by any other of the various contrivances for
such purposes which are familiar to engineers. The lid or plate. (Figure
14) of. the front mouth-piece is furnished with a screw nozzle a, for the admis
sion and working of the rod or lever connected to the plougher, Figure 16;
and the lid or plate, Figure 15; of the back mouth-piece is also furnished
with three similar nozzles for the admission and action of similar rods connected
to scrapers heréin-after described, or of a screw or rod connected to the
sliding plate or valve, hercin-after also described, for the purpose of opening

page_text: and closing the passage or channel for the coke or other carbonized substanco;
from the retort into the coke box. Figure 10 represents the upper and
lower plates of my improved retort, in connexion with each other and with
the front mouth-piece of the retort, as constructed in its most simple form,..
for my improved apparatus. The upper plate q is supplied at both its ends.
with flanches y and w to form the necessary attachments to the mouth-pieces.
of the retort, and which flanches, when the upper and lower plates of tho,
retort are connected with each other, overlap the outer rims of the bottom.
plate o. The bottom plate o is constructed with rims, as before described, for
the reception and cementing therein of the upper plate, and this bottom,
plate is also furnished at both ends with flanches extending downwards
for its connexion to the corresponding flanches of the lower side of the front.
mouth-piece, and of the flanch 6 of the coke box herein-after described. The
front mouth-piece is a chamber designed for the reception and station of the
plougher herein-after described, and is formed with flanches z at one end for
its connexion to its lid or cover (Figure 14), and with a plate v arising from.
the other end (and extending itself as a flanch around the mouth-piece, the
whole corresponding in size and figure to the size and figure of the retort,
and being fixed to the flanches of the upper plate thereof by bolts, screws, or:
other suitable contrivances, so as to form an air-tight connexion in the usual
way. At v, in the upper plate of the front mouth-piece, a square hole is
formed, which is designed to accord with the appendage of the valve box of
the feeder herein-after described. Figure 11 is a representation of the lower.
plate of the retort, with its rims and flanches. Figure 12 represents the
back mouth-piece of the retort, which forms the upper part of the coke box,
and the receptacle for the scrapers and slide valve herein-after described.
This mouth-piece is similarly constructed to the front mouth-piece before
described, except that the lower plate of the mouth-piece does not extend
to the edge of the retort, but only so far as the line c, in order that when the
parts of the retort are brought into opposition an opening or space may bo
left (as shown in the Drawing) between the edge of the bottom plate of the
retort and the line c for the discharge of coke into the coke box next herein-
after described, and which space is intended to be covered and unsealed by
the plate or sliding valve, Figure 24 (herein-after described), so as to render
the whole of that part of the apparatus air and gas tight. The said mouth-
piece having been attached to the flanches w of the upper plate of the retort,
the coke box, Figure 13, is to be attached by its flanches a, a, a, to the
bottom plate of the mouth-piece, and by its flanch 6 to the flanch of the bottom
plate of the retort, with bolts or screws, and to be rendered air and gas tight

page_text: by the usual contrivances. Grooves or sockets for the reception and channe
of the plate or slider (Figure 14) are to be cast around the plate, and fixed
to the interior lower surface of tho mouth-piece, in the proper position for
securing the due operation of the plate or valve. The orifice h in the back
mouth-piece is intended for the insertion of the pipe conveying the gas
produced in the retort to the cistern K, Figure 2, and the small orifice w is
made for the reception of the bent water pipo M, Figure 2, designed to
convey a small stream or jet of water upon the shelf s, Figure 8 (the edges
of which ff, are flanched upwards), suspended from side to side of the retort
upon lidges r, r, Figure 8, cast for that purpose in the interior of the upper
plate of the retort. Figuro 14 represents the lid or cover of the front mouth-
piece of the retort, with its nozzle or stuffing boxes, for the passage and
working of the rod or lever of the plougher hercin-after described, and Figure
15 represents tho lid or cover of the back mouth-piece, with its three nozzles or
stuffing boxes for the admission and working of the levers or screw attached
to the scrapers and sliding valve herein-after also described. Figure 16
represents the plougher before mentioned, being a cross bar of iron extending
horizontally from side to sido of the interior of the retort, and connected with
the rod from the cross bar g. A number of wedge-like teeth t, t, project,
for the purpose of ploughing and arranging the coal in thin long strata, by
which means it may be completely exposed to the most intense action of the
heat on all its sides, and the gases it contains be quickly and effectually
extricated. Front and side Diagrams of the teeth of the plougher are shewn
in Figures 10 and 20. The number of teeth will depend upon the size of tho
retort, and they may be formed either single pointed, as shewn by Figure 20,
or triple pointed, as at Fig. 21, the side points in such latter case not being
so deep as the middle point. The side teeth are furnished with small wheels,
for the purpose of facilitating the motion of the plougher. This plougher is
designed to push forward and distributo the coal, when supplied to the retort,
in thin layers or ridges upon tho interior surface of one half longitudinally
or thereabouts of the bottom plate of such retort, and also to aid the scrapers
in the expulsion therefrom of the coke on the further and other half of
the retort from which the gases have been extricated, and also to replace the.
expelled coke by thrusting the partially carbonized coal still further forwards.
The scrapers are two in number, one of which is represented by Figures 22.
and 23. Their office is, with the assistance of the plougher, to distribute.
and withdraw the materials subjected in the retort to the distillatory process.
They may be composed of plates of iron of the figure represented in the said
Drawings, and are fixed to a rod, as herein-after described. Figure 24 is a

page_text: horizontal plate of iron, extending to nearly the whole width of the back
mouth-piece or chamber, Figure 12, intended to act as a sliding valve, and
close the passage into the coke box whilst the coke is being withdrawn
therefrom, and during the process of distillation, so as to preclude the admis-
sion of atmospheric air or the escape of gas when the cover with which the
coke box at its lower orifice is to be supplied is opened for discharging its
contents. The said plate or sliding valve is wedge-formed on its upper surface,
to slide and fit into grooves or channels made for its reception in the upper.
plate of the mouth-piece and coke box, as before described, and it should
be coated on its upper surface with a thin layer of fire clay, to preserve it from
oxidation, and great care should be observed in keeping the channel closed
at all other times than those of discharging the carbonized contents of the
retort. The cover for the lower orifice of the coke box may also be formed
by a plate sliding in a groove, or otherwise, as may be deemed most secure
or convenient, and great caution.should be observed to keep the same closed
whenever the upper valve of the coke box is open, and at all other times,
except for the necessary discharge of its contents. Figure 23 is a sectional
representation of one of the nozzles or stuffing boxes attached to the lids or
covers of the mouth-pieces of the retort, and with the rod or lever which:
imparts the necessary motions to the plougher and scrapers respectively inserted.
through the same, the several nozzles agreeing with each other in their.
construction and form. The present section will be sufficient to illustrate.
the whole. c is the lid or cover of the mouth-piece. a is the nozzle firmly.
attached thereto or constructed therewith, having a concavity formed at b for
the reception of the necessary stuffing, and which is pressed down and secured
by the perforated screw cap d. r is the rod in the present instance firmly
attached to the scrapers, but the rod or screw, which is connected either to.
the plougher or to the slide valve (both of which are intended to remain in.
their horizontal positions), must be permitted to revolve without impediment.
in the socket formed in those parts of the apparatus, and through which it.
is to be fixed by a collar or nut, or any other suitable contrivance. The.
exterior ends of the rods or levers severally connected with the plougher,
the scrapers, and the slide valve, are supplied with a female screw, as at f,
Figure 16, which is adapted to the male screw h, Figure 17, of the rods
attached thereto that are to move them in the retort. By this means
when the operation for which the plougher, the scrapers, and the slide
valve are respectively designed is completed, and those parts of the apparatus.
have been brought back to their original positions, the levers may be
unserewed and detached; and as a further protection against the escape of

page_text: gas or the admission of atinospheric air, when the long levers are detached
the nut Figure 18 may be screwed into the female screw of that part of the
rod which rests in the nozzle or stuffing boxes before described, the depth
of which should be such as to permit the surface of the nut to be brought
flush with the edge of the nozzle (or screw cap d) to which it is to be
applied.
But I declare that I do not claim any novelty in or limit myself to this
construction of the rods, nor in or to their modes of connexion or air-tight
admission to the machinery to which they are applied, neither do I claim any
novelty in the construction or use of the scraper herein-before described.
Figure 25 represents a hopper or feeder with my improved valve for supplying
the retort with the necessary charges of coal without admitting the atmospheric
air or permitting the escape of gas. The hopper h, Figures 25 and 26, is to bo
supplied with a sliding plate or other moveable cover or lid (not necessary to be
shewn) to be fitted air-tight thereto. p, p, is a bent plate of metal flanched at
its edges and springing out or expanding from the exterior sides of the hopper
just above the lower edges thereof. The flanches of the said bent plate are to
form attachments to the corresponding flanches of the channel piece c, and into
the combined circumference of which is fitted the cone valve v, hercin-after
described, the said channel piece being attached by its flanch d to the front
mouth-piece v, Figure 10. Figure 27 represents a hollow cylinder of metal,
slightly coned, with openings at o and p. The opening o is to be of sufficicent
capacity to receive the lower edges of the hopper h, Figures 25 and 26, and
to leave a small space around the same for the protrusion or insertion of
packing or stuffing; and the lower opening p should be of equal breadth and
length with the corresponding opening or channel through the solid coned
cylinder, Figure 28, with which it is to be fitted. The said solid cylinder
at its larger extremity is supplied with a short shaft s, from which arises a
square head t, to which is to be fitted a moveable spanner or key. The two
cones act upon the principle of the common cock, and form a valve by which
a communication between the hopper and the interior of the retort may be
shut off or opened at pleasure. The cones are made air-tight at the smaller
extremity by an annular collar a of lead or other soft medal, or by a packing or
stuffing confined and pressed by a solid cap c screwed up and secured by any
of the usual means for rendering such apparatus air-tight at the larger
extremity. This object is effected by means of an annular collar of metal,
enclosing between itself and that end of the cone packing or stuffing, aud
being itself secured by a cap d furnished with an orifice to fit upon the
shaft s. This cap is to be secured into or upon the hollow cylinder, and

page_text: furnished with screws, by which the required pressure may be applied to the
enclosed collar or ring and to the stuffing against which it is urged. These
screws may also be applied for the purpose of screwing up the solid tightly
into the hollow cone, by which means it can be made to fit without that
nicety of construction which would otherwise be requisite. Stuffing or
packing should also be applied to prevent the escape of gas between the
surfaces of the hollow cylinder and the plates of metal, before described, by
which it is surrounded, for which purpose a small portion of the upper surface
of the hollow cylinder, as shewn at e, e, Figure 25, is constructed with a bend
or concavity. The same object is also to be effected by a slight curvature in
the circular part of the channel piece, as shewn at ff. The stuffing or
packing for any of the purposes herein mentioned may be composed of cork,
tow, hemp, lead, or any of the packings or lutes usually employed for such
purposes, and rendered capable of resisting the action of heat; but that
which is generally adopted by me is composed of cork, tow, or other fibrous or
expansive material boiled in and saturated with a composition formed by the
following means (which I state merely for the purpose of explanation, and not
as claiming any novelty in the same or of confining myself thereto) :-Dissolvė
separately one pound of alum and two pounds of soda in sufficient quantity to
melt them; mix them together and a precipitate will be formed in white flakes ;
beat a pound of this precipitate together into one homogenous mass; add
thereto about a pound of sulphate of iron, and boil therewith and therein the
substance intended to be employed for the purpose of packing or stuffing.
The feeder above described may be supported by iron props, bars, or
staunchions, or by other appropriate means to support its weight. M;
Figure 2, is a bent pipe of small diameter opening into the back end of the
retort, to introduce a small stream or jet of water upon a plate of iron or
other suitable material, shewn at 8, Figure 8, about three inches in width;
with its edges f, f, flanched upwards, suspended from side to side of the
retort, near the back end thereof, upon small ledges or shelves 1, r, cast
with the upper plate of the retort. The water thus introduced is repelled
from the plate or converted into steam by the internal heat of the retort,
and the gases which are evolved from the coals in the earlier stages of
barbonization, being compelled to pass through the steam thus treated, the tar
and other carbonaceous products of the coal thereby become precipitated upon
the surface of the heated coke beneath, where they are again distilled and
converted into gas of a more elastic inflammable nature. The gas or gases
produced in the retort pass from thence through the pipe J, Figure 2, arising
out of the mouth-piece H, into the cistern K.. This cistern, as shewn at

page_text: Figure 29, is composed of cast iron or other suitable material closed on
all sides, except for the admission of the pipes for the entrance and discharge
of the gas, and divided into two compartments by a partition plate C, which
descends from the cover or lid of the cistern to within two or three inches of
the bottom thereof. The gases being introduced by the pipe J into the
compartment b, and above the surface of the liquid or semi-liquid deposits that
are formed therein by condensation, and then passing through those deposits
and under the partition C, make their escape by the pipe L, the orifice of
which being lower than the pipe J admits of the escape of the said products
when they accumulate beyond the surface of the said pipe, and which with
the gases descend into the digester D. The lid or cover of the cistern is made
of a plate of metal fixed by flanches and screws, or by other usual means, and
which may be removed for the purpose of cleansing the interior of the
cistern or the pipes, and then be re-applied, being rendered air-tight by luting
at its flanches or otherwise by any of the usual modes. Within the walls of the
oven, passing underneath one side of the retort and exposed to the lateral
action of the furnace, I insert the digester D. This digester in its best form
is composed of a large cylinder divided into compartments, as herein-after
described. The ends of the digester project beyond the said walls, and into
one of its outer extremities, upon the side most exposed to the action of
the furnace, descends the pipe L. From the other extremity of the digester
proceeds the eduction pipe E, through which the gas ultimately escapes into
the expansion chamber, Figure 30, containing water, to act as an intermediate
seal between the dip pipe e and the purifier, to which the gas is to be from
thence conveyed through the pipe f. The digester is divided into compart-
ments by an apparatus, represented by Figure 31, fitting its interior and
consisting of three plates (of equal length to the digester) radiating from
a common centre, two of which are cut in the manner thereby shewn, tho
other being an unbroken plane. The compartments thus formed in the
digester are designed for the reception of coke, old iron, and lime, or other
similar detersive and refining substances, over and through which the gas
travels before it gains its exit from the digester, the spaces left between
the tongues of the plates t, t, affording passages of intercommunication from
chamber to chamber, as indicated by the direction of the arrows, and
ultimately to the eduction pipo E. The digester may be formed either of
metal or of carthenware, but in the former case it should be lined with a
coating of fire-clay cement to preservo it from oxidation, and for receiving
which its interior surface should be cast unevenly or roughly. This coating of
cement will also prevent the passage of gas from one chamber to the other,

page_text: between the edges of the plates and the interior surface of the cylinder.
When the digester has been charged with the substances intended to bo
employed therein, it should be closed at both ends with air-tight lids or
covers screwed to a cross bar and luted, in a similar manner to that usually
adopted for retorts. The lids or covers should be furnished with interior
grooves or channels. for the reception of the edges of the plates of the digester,
and should contain a luting (of any ordinary description) to prevent the
passage of gas between the edges of those plates and the interior surfaces
of the lids or covers. I do not confine or limit myself to the form of the
digester, nor to the use thereof in conjunction with retorts of the nature above
described, as the same may beneficially be applied to gas retorts of every
description with proper modifications in its capacity, and for the setting or
fixing of the same, and for the introduction and discharge of the gases
thereto and therefrom, which modifications will suggest themselves to any.
practical man of moderate skill.
And I claim the digester divided into compartments, as above described,
and subjected to heat in all its applications, for the generating and purifying
of gas for the purposes of illumination, as part of my Invention secured to
me by the said Letters Patent.
Figure 82 represents my improved purifyer. p is a case or reservoir of an
inverted pyramidal figure, the upper portion of which is made air-tight by a.
flanched lid g, upon and opening into which is the feeder or hopper f, similarly
closed and supplied with a slide valve g to open or close the communication
between them. This hopper is designed to supply the purifier with the
necessary charges of lime or other detersive and refining ingredients to be
used as purifiers of gas. h. is a pipe to conduct the gas after it has passed
through the lime or other detersive substance contained in the purifier
to a washer, or if necessary to an additional purifier, and thence to the
gas holder. Over this pipe, in the interior of the purifier, falls a slightly
bent ledge to prevent the fall of lime therein. wis a bent pipe inserted
through the lid of the purifier (but the position of which may be varied)
for the injection of an occasional supply of water; if it should be found
requisite to facilitate the action of the lime. The circles represented at
are sockets for the reception of small cylindrical bars of iron or other suitable
material; the said bars being passed through air-tight nozzles or stuffing boxes
made for that purpose in the opposite side of the purifier or case p (which it
is not necessary to shew). These bars form a grating for the bearing and
downward passage of the lime or other detersivo substance supplied to tho
purifier by the feeder f; and for the upward passage of the gas passing through

page_text: the purifier. These nozzles permit the bars to be withdrawn separately or
together, for the purpose of cleansing the interior apparatus, or of introducing
new bars when the old ones become impaired. . is a chamber flanched or
otherwise fixed to the side of the purifier, and containing a slide with
oblong apertures for the regulation of the passage of the lime between
the bars of the grating, and forming, when inserted, an auxiliary grating
to diminish the apertures from the upper chamber p.to the lower chamber,
of the purifier to any required extent. This slide may be connected to a screw
or lever working air-tight through the end piece of the chamber y. The case
or reservoir p of the purifier opens into the chamber c and communicates with
the square pipe d, bent at its other extremity, so that it may dip into a
reservoir of water forming a seal to prevent the passage of the gas that
way, and into which the lime is to be discharged. e is an opening to
admit the passage of a rod for the occasional cleansing of the tube. d, but
closed whilst the process of purification is proceeding. m is the pipe by
which the gas to be purified is introduced; and n is a plate or slide
valve to work air-tight, for the purpose of closing the tube and precluding
the escape of gas when the. purifier is not in action, or during the time
that the reservoir into which that tube dips is being cleared out. To work
the apparatus above describe:l, after heating the retort to the requisite tem-
perature, and charging or filling the chamber of the digester, into which the
gas, first passes from the retort, with coke, and filling the. second chamber
thereof with old iron or old iron and lime, or lime only, and the third also
with old iron, or if applied to cylindrical or other retorts, in which the. gas is
not passed over the surfaces of heated coke therein, with coke, or filling, such
chambers with other ingredients having proper affinities, for the gases extri-
cated in its distillatory process and detrimental to the purposes of illumination,
the retort is to be charged with coal (or other material), to the extent of half
its length, by opening the cone valve of the hopper A, Figure 1, to the extent
of one quarter of its entire revolution, so that the coal or other material) may
fall into the bottom of the retort. This charge is dispersed-and-arranged-in
ridges or furrows over and throughout the first half division of the retort by
means of the plougher, which I move by, the extremity of its lever passing
through the air-tight nozzle or stuffing box, as before described; and when
this half charge has been subjected to the action of the retort for about an
hour, and is partially, decomposed, I move it forward to and distribute it over
the other or back half division of the retort by the action of the plougher in
front of the retort bed, assisted, if. necessary, by the scrapers at the other. or back
end of the retort, similarly operating by means of levers, as before described:

page_text: As soon as this is effected (the hopper having in the mean time been recharged.)
supply the first half of the retort with another half charge of coals, which
bus completes the full charge to the retort, so as to permit a continuous supply
of half charges therefrom as occasion requires. When the full charge of the
etort has been thus completed I admit a small stream of water by the pipe M,
Figure 2, which is immediately converted into steam, through which the gases
pass, as before explained, before they gain their exit by the pipe J into the
cistern K, from whence they are conveyed by the pipe L to the digester which
bas been previously charged, as before described. When the coal or coke at the
back end of the retort has been completely distilled or carbonized the injection
of water is to be suspended and the slide valve, Figure 24, is to be opened by
its lever or screw, when the coke must be raked into the coke box, Figure 13,
by means of the scrapers; the valve must be then again closed, the coal
partially decomposed brought forward, as before described, another charge be
introduced, and the injection of water again renewed; the coke in the box,
Figure 13, may then be withdrawn by opening its cover or slide, with which it
is provided at its lower orifice, and again closed when that operation has been
performed. The quantity of water to be admitted will depend on the quantity
of the coals employed, but a steam of one gallon and a half of water to a ton
of the best New Castle coals be sufficient. The plougher and scrapers, when
the service for which they are designed has been performed, are to be returned
to their stations in the mouth-pieces of the retort. The digester and its cor-
tents being beated by their contiguity to the furnace, their detersive, refining,
and productive operations upon the gases which flow through them is much
increased and facilitated, and after the gases have traversed the several
chambers of the digester it is conducted as before stated by the pipe E into
the expansion chamber, Figure 30, and thence to the purifier by the pipe f,
Figure 30, where it becomes submitted to the action of that portion of the
apparatus. By means of the hopper or feeder f, Figure 32, a sufficient
quantity of unslacked lime is furnished to the purifier p, and the gases
the pipe m,
intended to be purified being then admitted to the purifier
will pass upwards through the lime, causing the latter to fall in powder
between the bars x, and down the pipe d, contributing in its passage
downwards to the purification of the gases which are flowing over its surface
from the pipe m, on their way to the purifier. To facilitate the action
of the lime a small stream of water may be discharged into the purifier
through the pipe w, but it will not be requisite to introduce water when the
lime is sufficiently acted upon by the aqueous vapours, in combination with the
gases, so as to pass through the pipe d, and, which may be, ascertained, by
inspecting the water into which that pipe dips. The charge of lime or other

page_text: detersive material in the purifier is to be replenished before it is exhausted by
supplies from the feeder f, corresponding with the expenditure, and which may
be measured by the feeder f, and regulated by the slider n, herein-before
described. When the apparatus is applied to a different construction of retorts
than that above described, or in other positions, slight modifications in the
arrangements may be requisite to adapt it to its altered situation or form, but
it is unnecessary particularly to enter into detail of such modifications, or of the
dimensions applicable to various cases, as they will vary according to circum-
stances, attention to the remarks and the description given in the above
statement, and the Drawings referred to, being sufficient to lead any person
conversant with the manufacture of such apparatus generally to adopt the
dimensions and form to any particular case; and the arrangement, construction,
and connexions of many of the inner parts may be modified according to the
size of the apparatus, the situation in which it is placed, and the circumstances
governing the same, without at all deviating from my Invention as the same is
defined by these Presents and the Drawings hereto annexed. The various
parts may be constructed of such metals or substances as are suited to the
nature of the work to be performed, and the degree of strength, power, and
durability required.
Now whereas I, the said William Barnett, have, by these Presents and the
Drawings thereby referred to, in compliance with the said proviso, described
the nature of my said Invention of "Certain Improvements in Apparatus for
Generating and Purifying Gas for the Purposes of Illumination," and in what
manner the same is to be performed, I claim as my Invention the construc-
tion and application,-
First, of the said roofs or arches of ovens or retorts, beds for generating gas
for the purposes of illumination.
Secondly, of gas retorts formed in separate parts and united to each other
as above described.
Thirdly, of the digester divided into compartments as above mentioned,
and subjected to heat, for generating and purifying gas for the purposes of
illumination.
Fourthly, of the valves for feeding the retorts with and for discharging
therefrom, and the plougher for arranging therein the materials subjected to
distillation for the production of gas; and,
Fifthly, the purifier for purifying the gases obtained by distillation from coal
or other substances requiring such purification for the purposes of illumination.
I also claim, by virtue of the said Letters Patent, the exclusive use of the
said several improvements, either in combination with or apart from each other.
And such my Invention being, to the best of my knowledge and belief,

page_text: entirely new, and never before used in that part of His said Majesty's United
Kingdom of Great Britain and Ireland called England, His said Dominion of
Wales, and Town of Berwick-upon-Tweed, I do hereby declare this to be iny
Specification of the same, and that I do verily believe this my said Specifica-
tion doth comply in all respects fully, and without reserve or disguise, with the
proviso in the said herein-before in part recited Letters Patent contained.
Wherefore I do hereby claim to maintain exclusive right and privilege to my
siad Invention.
And lastly, I declare that I do not claim originality in the use of any of the
substances or fluids employed, either for the construction of the apparatus
(except the said roofs or arches), or for the production or for the purification
of gas, for the purposes aforesaid. And although I have described many
parts of the said apparatus, and means of connecting them, which are not new,
I have done so solely for the purpose of rendering my Invention clearly under-
stood, and shewing the different combination of the parts, and not as claiming
them (except the mode described for combining the upper with the lower
plates of gas retorts). And I accordingly disclaim the same, and do not
confine myself to the particular modes described.
In witness whereof, I, the said William Barnett, have hereunto set my
hand and seal, this Twenty-second day of December, One thousand
Landed and thirty-six.