A NEW AND IMPROVED APPARATUS FOR PURIFYING GAS USED FOR ILLUMINATION
Year: 1819

page_text: TO ALL TO WHOM THESE. PRESENTS SHALL COME, I, JOHN'
GRAFTON, Engineer to the Edinburgh Gas Light Company, send greeting.
WHEREAS His present most Excellent Majesty King George the Third
did; by His Royal Letters Patent under the Great Seal of the United King-
dom of Great Britain and Ireland, bearing date at Westminster, the
Eighteenth day of November, in the sixtieth year of His reign, give and grant
unto me, the said John Grafton, my executors, administrators, and assigns,
His special licence, full power, sole privilege and authority, that I, the
said John Grafton, my executors, administrators, and assigns, during the
term of years therein expressed, should and lawfully might make, use,
exercise, and vend, my Invention of "A NEW AND IMPROVED APPARATUS FOR
PURIFYING GAS USED FOR ILLUMINATION," within England, Wales, and the
Town of Berwick-upon-Tweed, in such manner as to me, the said John
Grafton, my executors, administrators, and assigns, should in our discretion
seem meet; in which said Letters Patent is contained a proviso that if I,
the said John Grafton, should not particularly describe and ascertain the
nature of my said Invention, and in what manner the same is to be performed;
by an instrument in writing under my hand and seal, and cause the same to
be inrolled in His Majesty's High Court of Chancery within two calendar
months next and immediately after the date of the said recited Letters
Patent, that then the said Letters Patent, and all liberties and advantages
whatsoever thereby granted, should utterly cease, determine, and become void,
as in and by the said recited Letters Patent, relation being thereunto bad
may more fully and at large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
John Grafton, do hereby declare that the nature of my said Invention, and in
what manner the same is to be performed, are particularly described and
ascertained in manner following (that is to say):-
My new and improved method of purifying gas for purposes of illumination
consists, first, in preparing or compounding the lime which is used for purifying
the with
gas pot or pearl ashes, and charcoal or coke may be added. Thus I
take lime recently burned and unslacked, and I pour upon it a strong solution
of pot or pearl ashes in water, the quantity of the said solution to be such as
will make the lime slack or fall into powder; I then add a fifth part by weight
(more or less) of dry potashes or pearlashes, and also a fourth part by weight
(more or less) of wood charcoal, or coal coke in small pieces may be added,
these materials to be very perfectly mixed together. This compound of lime
and alkali, either with or without charcoal or coke, I call my purifying
material.
The second part of my new and improved method of purifying gas consists
in certain additions to, and arrangements of, the parts of the purifying appara-
tus, wherein the gas is to be subjected to the action of the purifying material.
By the said additions and improvements the purifying apparatus is adapted to
take in the purifying material, and spread the same in a layer or stratum of
even thickness upon a surface or web of wire cloth, or other suitable material,
through which gas can freely pass, which is extended in an horizontal plane
within the purifying vessel in such manner as to divide the internal capacity
one above the wire surface and stratum
thereof. into two compartments (viz¹),
The said upper and
of purifying material, and the other below the same.
lower compartments are subdivided by vertical partitions, which are so
arranged that those partitions which subdivide one compartment are situated
the other compartment. The
opposite the intervals between the partitions
object of this arrangement is to cause the gas to pass repeatedly thro' the
stratum of purifying material by alternately ascending and descending thro'
the different parts of the said stratum. For example, if the gas is first intro-
duced into one of the subdivisions of the lower compartment it will ascend
thro' the interstices of the wire cloth, and also thro' the stratum of purifying
material which lies upon it. The gas which so passes will enter into one of
the subdivisions of the upper compartment, from which it will escape by
descending thro' another part of the stratum into another of the lower sub-
divisions; from this it will again ascend thro' a different part of the stratum
into another upper subdivision, and so on to any required extent. The said
surface or web of wire cloth upon which the purifying material is spread can

page_text: be moved occasionally in order to remove the purifying material when it
becomes saturated with impurities, and to spread a fresh stratum thereon.. For
this purpose the web is extended between two horizontal rollers, one situated
at each end of the purifying vessel, and the two ends of the web being carried
over the said rollers are returned to meet each other, and are united together
so as to form an endless band or web, which being extended over the said
rollers, it will move or advance when the rollers are turned, and thereby the
stratum of purifying material will be carried forwards with it. The partitions
which subdivide the upper compartment can be removed or raised up to
permit the stratum to pass away with the moving web without interruption;
but when the purifying material is carried with the web round one of the
rollers it falls off, and is received in a refuse receptacle or chamber situated at
one end of the apparatus beneath the said roller, whilst that part of the web
which the purifying material has quitted continues to move towards the other
roller. To effectually clear away the stratum from the wire and open the
interstices thereof, revolving rollers, covered with hair bristles or other similar
substances, are applied near that part of the web where the purifying material
is intended to quit the same, and they act in the manner of circular or cylin-
drical revolving brushes to brush and clear out the interstices of the wire.
The fresh purifying material is put into a feeding receptacle chamber at one
end of the apparatus (viz.), at the opposite end to the before-mentioned refuse
chamber, which is for the purifying material which has already been used. The
feeding chamber is situated just above one of the rollers round which the
revolving web passes, and there is a sliding valve or door in the bottom of the
said chamber, which, being opened, the fresh purifying material is let down
upon the web, and when the same is put in motion, as before mentioned, it
carries forwards this fresh purifying material with it, and the partitions in the
upper compartment being raised up, as before mentioned, to a certain height
above the wire, in order to let the old purifying material pass away, the lower
edge of one the said partititions (viz), that which is nearest to the feeding
chamber, scrapes away or levels the surface of the fresh material, which is
carried along upon the wire so as to reduce it to a stratum of an even thick-
ness. The top or cover of the upper compartment of this purifying apparatus
is made to open, in order to give access to the interior; this cover may be
made to shut down into an hydraulic grove, or any other means by which a
close joint can be made. To render this my Specification more clear and
explicit, I have hereunto annexed Drawings of an apparatus for purifying
gas acccording to my improved method.
Fig. 1 is the outside view, sideways, of the whole purifying apparatus, placed

page_text: upon supports, which raise it two feet, more or less, from the ground. Fig. 2
is the outside view of the vessel, viewed at one end, shewing the feeding
chamber. Fig. 3 is an outside view of the other end of the vessel, shewing
the refuse chamber, which.. descends below the horizontal part of the vessel.
Fig. 4 is the inside longitudinal section of the whole vessel. seen sideways, to
shew the internal parts. Fig. 5 is a perpendicular section of the feeding
chamber. Fig. 6 is a plan of the vessel with the covers removed; and shews
the hydraulic groves' into which the edges of the covers descend. Fig. 7 is a
longitudinal view of the revolving brushes. The feeding chamber A, Figs. 1;
4, and 5, contains the purifying material. At the bottom of this chamber is
an aperture, provided with a sliding valve marked B, Figs. 4.and 5. When
this valve is slided horizontally in the direction from N. towards B, Fig. 4,
it opens about, one half of the breadth of the feeding chamber, and allows
the purifying material to descend into the chamber beneath. This valve
is opened or shut at pleasure by racks affixed to it, which racks are moved
by pinions attached to a-spindle passing thro' a stuffing .box, and turned
by a handle on the outside. See b, Fig. 1. The edges of the sliding valve B
are guided in groves fixed at the sides of the feeding chamber. An inclined
partition B, D, Fig. 4, is fixed in the lower part of: the feeding chamber.to
conduct the material into the aperture in the bottom of: the feeding chamber.
is
This sloping partition is not joined to the bottom of the chamber, but a space
left beneath it for the movement of the sliding valve, which retreats beneath the
sloping partition, when it is slided open. Within the feeding chamber an agitator
E, Figs. 4; 5, and 6, is placed; it is an axis, with a number of projecting arms or
radij, which extend nearly to the sides of the chamber, and the end of the axle
comes thro' the side of the chamber thro' a stuffing box, and can be turned by
a handle on the outside to agitate the purifying material and make it descend
freely. The feeding chamber is closed at top by a cover; the upper edge is
surrounded by an hydraulic grove, into which the edge of the cover descends.
The feeding chamber is situated over one end of a long horizontal vessel in
which the gas is purified. The upper part of this vessel is closed by two
or more moveable lids or covers fitted into a common hydraulic grove of a
sufficient depth, according to the pressure of the gas, say from five to twelve
inches, which grove extends all round the top edge of the vessel, forming. a
projection outside, and therefore does not diminish. the space within the vessel.
At one end of the purifying vessel, just beneath the feeding chamber, is a roller
G, Fig. 4, of wood or other suitable material.. It is about fifteen inches more
or less in diameter in the centre, and gradually lessening in a small degree
towards the extremities, like a wine cask. This roller extends across the

page_text: vessel, and turns round freely on pivots at the extremities of its axis. Near
the opposite end of the vessel is another roller H, Fig. 4, in all respects
the same as the former; it extends across the vessel immediately over the
refuse chamber F, but a foot more or less from the extremity of the vessel.
The two rollers-G and F are precisely on the same level. The roller: H is
turned round by its axle, which passes thro a common stuffing box to the
outside of the vessel, and has a handle H, Fig. 1, fixed on it. A web of wire
cloth, of brass or other suitable metal, or of chainwork of suitable...metal,
or any other suitable flexible material, is passed roundi both rollers, and
the two ends of the web are sewed or united together, so as to form
what is called an endless web. When the roller H, Fig. 4, over the refuse
chamber is turned, the circulating motion of the web will turn the other
roller G, Fig: 4. The web is marked in Fig. 4 by dotted lines, and is seen in
the Plan, Fig: 6. The web is about of, an inch at each side narrower than
the purifying vessel in which it is situated. The web is extended and
stretched by means of moveable sockets, in which the pivots of the axle
of the roller G, Fig. 4, are received. These sockets have shanks, see Fig. 8,
which come thro' the end of the vessel, and are adapted to receive screws,
which are fitted into stuffing boxes, and have a projecting head-on-the out-
side, whereby the roller G may be drawn back from the other roller H to
stretch the web at pleasure. At a few inches from the bottom of the purifying
vessel an inner bottom of iron or other suitable material is fixed, as shewn
at K, K, Fig. 4; it joins to the two sides of the vessel, but does not extend
further lengthways than to within six or eight inches of the rollers. From
this inner bottom three or four (more or less) partitions of wood or other
suitable material, as L, L, Fig. 4, are carried up to within one inch and a half
of the web. There is one of these partitions at each extremity of the.inner
bottom; they all extend quite across the purifying vessel, and are joined both
to the sides and to the inner bottom. Immediately beneath the upper part of
the web is an oblong frame M, M, Fig. 4, of wood or other suitable material;
the rails are three inches, less or more, broad, by one inch and a half, less or
more, thick. This frame is made to fit close to both sides of the purifying
vessel; and it has any number of cross bars of the same dimensions as the rim or
sides; there is one cross bar over each-fixed partition L, and these cross bars
are fastened to the upper edges of the fixed partition. The two extreme cross
bars of the frame are carried almost to touch the two rollers, and are hollowed
to the form of the rollers. Three sliding partitions or valves N, N, Figures 5
and 6, are fitted across the purifying vessel above the web and wooden frame!
When these partitions N, N, are shut down they touch the web, but when they

page_text: are drawn up their under edges rise four or six inches above the web. These
sliding partitions are placed close to the sides of the hydraulic groves, which
extend across the vessel to receive the edges of the covers. The middle parti-
tion N is placed over a cross bar of the wooden frame M, but in the intervals
between the fixed partition L, L, which are below the wooden frame. The
sliding partitions N, N, at the two extremities, are shut down on the web just
over those cross bars of the frame which rest on the top of the fixed parti-
tions L, L. The sliding partitions are raised by means of racks fixed to
them, worked by pinions; the axles of which go through stuffing boxes in
the sides of the vessel, and are turned by the handles applied on the outsides.
On the ends of these axles are ratchets with clicks, which prevent the pinions
turning back till intended. Each subdivision or chamber formed by the fixed
wooden partitions L on the inner bottom can be opened by a door at one side,
fixed by hinges, and shut up fast by a wedge or key; the doors to be luted.
The refuse chamber F is opened by a door at the bottom. The gas is intro-
duced thro' the pipe P in the side of the vessel, and enters into a subdivision
of the lower compartment formed between the web and the inner bottom K,
Fig. 4. The gas is first introduced into that subdivision which is next to the
refuse chamber F, Figure 4, and the pipe Q, thro' which the gas passes off
purified, is in the side of the vessel, and communicates with that subdivision of
the lower compartment which is at the other extremity of the apparatus.
R, R, Figures 4 and 7, are two cylindrical brushes formed with hair bristles
all round; they are five inches more or less in diameter, and extend all across
the breadth of the vessel. These brushes are placed under that roller which
is over the refuse chamber. These two brushes are made to revolve rapidly
by means of pinions fixed on the extremities of their axles at the outside of the
vessel, from a toothed wheel which is fixed on the end of the axle of the
roller H, as shewn at R, S, Fig. 1. To prepare this apparatus for work, the
feeding chamber is filled with the purifying material; the moveable parti-
tions N, N, Figure 4, which extend across the upper compartment of the
purifying vessel, are all drawn up clear from the web; the sliding valve or
door B, Fig. 4, at the bottom of the feeding chamber, is opened and the
purifying material is thereby let down upon that part of the web which is
immediately under it; the roller H, Figure 4, which is situated over the refuse
chamber, is then turned, and causes the upper part of the web to move in
the direction from the feeding chamber towards the opposite end of the appa-
ratus, and carries the purifying material with it; the thickness of the stratum
of the material is regulated from two to six inches, as is required, by the lower
edge of the first moveable partition N, beneath which it passes immediately

page_text: after quitting the feeding chamber, and, the moveable partition is drawn up
more or less accordingly. In this manner the web is moved forwards till
the whole upper part is covered with the purifying material (viz'), from the
feeding chamber to the roller H. The moveable partitions are then carefully
shut down, and the gas introduced by the pipe P, Figures 1 and 6, into that
subdivision of the lower compartment of the purifying vessel which is next to
the refuse chamber, which subdivision I will call the first. The gas.passes up
thro' the web and purifying material, as shewn by the arrows in Fig. 4, that
subdivision of the upper compartment which is immediately above (viz.) that
which is formed between the two moveable partitions N, nearest to the refuse
chamber. From this subdivision (which I call the second), the gas passes down
again thro' the web and purifying material into the next lower subdivision
(which call Number 3), and from this it passes up into the next upper chamber
Number 4, and so alternately ascending and descending any required number
of times thro' the wire and purifying material, according to the number of
subdivisons or chambers, as is clearly indicated by the arrows shewn in Fig. 4.
The gas finally passes off purified through the pipe Q, Fig. 1 and Fig. 6, from
the last subdivision of the lower compartment. That part of the layer of
purifying material which is in the subdivision No. 2, or nearest to the refuse
chamber, which will be first rendered impure, because the raw gas passes first
thro' that part, and therefore communicates the greatest portion of its impu-
rities. When this part of the purifying material has become useless it is
changed in the following manner, (viz):-The sliding. valve B, Fig. 4, is
opened, and the moveable partitions N are all raised up, and the roller H, over
the refuse chamber, is turned by its handle; and it should be so. constructed
that one revolution will carry the web forwards just so much as to throw the
charge of purifying material contained in the subdivision No. 2 over into
the refuse chamber. By the same movement of the web that part of the
stratum of purifying material which was in the upper subdivision No. 4 will
be brought into the subdivision No. 2; or if there were a greater number
of subdivisions each portion would be brought forward one subdivision towards
the refuse chamber, and fresh materials will be supplied from the feeding
chamber to that subdivision which is nearest to the same. When the mate-
rial has been changed in this manner the moveable partitions are all shut
down, the valve B is closed, and the purifying process is renewed, and so on
as long as the apparatus is kept at work.
From the aforesaid description it is obvious that by this manner of renewing
the purifying material the raw gas which is most impure is first passed thro'
that portion of the material which has already served once, and therefore has

page_text: attracted some portion of impurities; but this raw gas being loaded with such
impurities: will leave a portion thereof in the impure material. The gas being
then in a purer state is next passed through a fresher part of the material,
which will therefore extract more impurities, and, finally, the gas is passed
thro' the fresh material which has the greatest power to absorb the remaining
impurities. For large gas works the purifying vessel may be extended to any
number of subdivisions or compartments as is found requisite...
In witness whereof, I, the said John Grafton, have liereunto set my hand
and seal, this Eighteenth day of January, in the year of our Lord One
thousand eight hundred and twenty.
JOHN (L.S.)
GRAFTON.
AND BE IT REMEMBERED, that on the Eighteenth day of January,
in the sixtieth year of the reign of His Majesty King George the Third, the
said John Grafton came before our said Lord the King in His Chancery,
and acknowledged the Instrument aforesaid, and all and every thing therein
contained and specified, in form above written. And also the Instrument
aforesaid was stamped according to the tenor of the Statute made in the fifty-
fifth year of His said Majesty's reign.