IMPROVEMENTS IN APPARATUS FOR THE MORE ECONOMICAL MANUFACTURE AND SUPPLY OF ILLUMINATING GAS
Year: 1875

page_text: LETTERS PATENT to George Anderson, of 4, Cannon Row, in the City
of Westminster, for the Invention of " IMPROVEMENTS IN APPARATUS
FOR THE MORE ECONOMICAL MANUFACTURE AND SUPPLY OF ILLUMINATING
GAS."
Scaled the 16th October 1875, and dated the 12th August 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
ANDERSON, of 4, Cannon Row, in the City of Westminster, send
greeting.
WHEREAS I am in possession of an Invention for "IMPROVEMENTS IN
APPARATUS FOR THE MORE ECONOMICAL MANUFACTURE AND SUPPLY OF ILLUMINATING
GAS," and have petitioned Her most Excellent Majesty Queen Victoria
to grant unto me, my executors, administrators, and assigns, Her Royal
Letters Patent for the same, and have made solemn Declaration that I

page_text: am the true and first Inventor thereof, and that the same is not in use
by any other person or persons to the best of my knowledge and
belief.
NOW KNOW YE, that I, the said George Anderson, do hereby declare
the nature of the said Invention, to be as follows, reference being had
to the accompanying Drawings and to the letters and figures marked
thereon, that is to say :-
Anderson's Improvements in Apparatus for Gas Making.
am the true and first Inventor thereof, and that the same is not in use
by any other person or persons to the best of my knowledge and
belief.
NOW KNOW YE, that I, the said George Anderson, do hereby declare
the nature of the said Invention, to be as follows, reference being had
to the accompanying Drawings and to the letters and figures marked
thereon, that is to say :-
These improvements consist, —
Firstly. In the construction of retort houses.
Secondly. In the construction of condensers.
Thirdly. In the construction of washers.
Fourthly. In the construction of wet purifiers.
Fifthly. In the construction of dry purifiers.
And, Sixthly. In the construction of houses for the revivification of
the metallic oxides used in dry purifiers.
'
The Construction of Retort Houses.-Hitherto the practice has been
to construct a house of brick or stone, on the floor of which the retorts
stand, and when a second or third range of retorts have been required
to build a second or third house for such retorts. It has also been
customary to build coal stores immediately in connection with those
retort houses with openings in the retort house walls through which to
fetch the coal from the stores to the retorts where it has to be made into
gas. This repetition of houses is very expensive, and the coal stores
adjoining them prevent ventilation and make the retort houses, where
great heat is produced, very sultry and uncomfortable for the men.
A cross section of retort houses and coal stores for two ranges, accor-
ding to the existing mode, is shewn at Fig. 4 for the purpose of shewing
the ground space occupied in comparison with that necessary according
to my proposed mode. To remedy those evils it is proposed to construct
only one house for any number of ranges of retorts. Drawing No. 1
shews such a house into which three ranges of retorts have been already
placed, Figs. 1, 2, and 3. The end walls of those retort houses being
those at the extreme ends of the settings of retorts, it is proposed to
build of masonry, as has hitherto been practiced, but there will be no

page_text: walls between the several ranges of retorts, only columns to carry
girders on which the roofs will rest; and it is convenient to have them
in number of one column opposite the division wall of every third setting
of retorts. Fig. 3 shews a longitudinal section of such a house, there
being 20 settings of retorts, and the roof supported on a lattice girder
resting on the masonry of the house at each end and on 8 columns
between. The last row of columns at any time being those outside the
last range of retorts erected will have brickwork filled in between them
for the comfort of the men, which brickwork will be removed and
similarly placed when another range of retorts and necessarily another
line of columns have been erected, which in ordinary cases will be about
once in every five years.
The distance between the several ranges of retorts will be sufficient to
hold a considerable quantity of coal, that shewn on the Drawing, Fig. 2,
being equal to that required in a week; but this can be increased to any
quantity desired by merely setting the ranges of retorts farther apart
and making the roofs wider or of greater span.
Fig. 1 represents retorts worked from stages; Fig. 2 represents them
as worked from the floor.
The roofs covering the retort house may be of the usual width, as shewn
in Fig. 2, or they may be of only one half of that width and double the
number, as shewn at Fig. 1, in which case they can be made of much
lighter scantling and consequently at considerably less cost. In this latter
case the columns that support the roofs shewn close to the front of the
retorts may be placed one opposite the division wall of every third setting
of retorts, and within the line of the retort mouth fastenings so as not to
interrupt the passage in front of the retorts. Advantage may be taken
of that line of columns to support the hydraulic main from brackets
attached to the columns, and the pipes from the retorts to the hydraulic
main bent over in an opposite direction to what they usually are when
the hydraulic main is placed on the retort beds, giving the hydraulic
main a permanent and non-shifting foundation, and not liable to
breakage or getting out of level, which it is when subject to the
expansion and contraction of the retort beds, besides keeping it cooler
and preventing deposition of pitch within it, all which defects happen
with hydraulic mains set on top of the retort beds. The benefits
derivable from this mode of constructing retort houses are,-
-
First. The building of the houses can be done at much less cost than

page_text: in the present plan of building a separate house for each range of
retorts.
Second. The greater portion of all the coals used, being put within
the retort house they will be subjected to the current of warm dry air
continually passing through it, and become much drier than when placed
in coal stores, which will save fuel and add to the yield of gas obtained
from the coal.
Third. The cost of manual labour will be less when coal is placed
before the retorts than when placed in a store, from whence they must
be brought before they can be converted into gas.
Fourth. There will be a more thorough ventilation through the wide
open space formed in such a house, and without those cutting currents
which are usual in single houses, of much narrower dimensions, and
therefore be more healthful to the men employed.
Second. Improvements in Condensers.-The end desired to be attained
here is to give the gas manufacturers a ready means of keeping the tem-
perature of the gas gradually reducing without getting too low, when as
in frosty weather it is apt to throw out a portion of the light giving
elements and so reduce the illuminating power of the gas. Figs. 5
and 6 show how this is to be effected; Fig. 5 being an end, and Fig. 6,
a side elevation of the apparatus.
The condenser may either be of the vertical or horizontal form, but
I prefer the latter as being by far the cheaper and more effective. It
consists of a double row of pipes which may be as as often repeated or of
any convenient length required, according to the quantity of gas to be
purified, or in ordinary phrase condensed.
The Drawing shews 10 double rows of pipes, to the lower six rows of
which are attached three of "Anderson's Patent four-way valves."
The gas is allowed to pass through the upper rows of pipes in the
ordinary manner, and while its temperature, as shewn by a thermometer
is not below 50 degrees Fahrenheit, equal to 11 degrees centigrade. At
the outlet the valves are set to permit the gas to pass along all the pipes
in succession, but on any appearance of a lower temperature one or
more of the valves are turned, as shewn on the upper valve A, Fig. 5,
by which the gas will only pass through two of the four pipes to which

page_text: it is attached; thus if all three valves were so set the gas would only
pass through six out of the twelve pipes.
In cold countries the whole of the pipes might be similarly valved, in
which case the cooling power of the condenser could be reduced one
half.
Cleaning doors are bolted to the pipes at each end, and by the use of
the valves a portion of the condenser can be thrown out of action and
cleaned out without by passing the whole condenser or stopping the
manufacture of the gas while cleaning it out. A series of slide valves
or any other kind of valve can be employed to perform the same
function, but those shewn are considered the best for the purpose.
Fig. 6 shews a side elevation of the condenser; the arrows indicate the
direction in which the gas flows, entering at the top row of pipes and
issuing at the lower row of pipes.
When the condenser is erected of the vertical form, the four-way
valves will be of the ordinary kind, as shown, but when erected of the
horizontal kind the four-way valves will be of the form shown in section
at Fig. 7, with pipe B, as shewn below, to permit of the flow of condensed
liquids.
Third. Improvements in the Construction of Washers.-My improve-
ments consist in the use of a vessel very much smaller than an ordinary
scrubber, containing a series of shallow pans or tanks to contain the
purifying liquid, each having a drum C, the circumference of which
throughout its whole length is fitted with a brush D of whalebone or
other coarse fibre. This brush drum is made to closely fit to the chamber
in which it is placed, and the lower edge of it dips into the purifying
liquid; motion is given to these drums from the outside in the contrary
direction to that in which the gas (shown as arrows in Fig. 8) is passing,
by which the brush licks up the liquid, and the gas having to pass
through the fibres of the brush a large amount of wet surface is presented
to the gas on which it deposits its impuritics which are washed off by
the revolving of the drums.
The gas is caused to pass into the vessel below round each brush in
succession until it passes off at the top. The liquid is poured in at the
top and wets the top brush, thence it descends in the pipe in which the

page_text: :
the same direction as the gas, and its purifying efficiency will be
impaired.
The plates in the end of the vessel are constructed to be removed for
the examination or replacement of the brushes as they wear out. The
drum must be constructed so that the gas cannot pass from the inlet
pipe on one side to the outlet pipe on the opposite side without passing
round the upper part of the brush. This is effected either by having the
drum close at the circumference and lower edge, dipping into the water,
or bars may be attached across the drum, say 6 in the circumference, so
that before one leaves the water at least one other will have entered,
and thus formed a partition across the vessel sealed in the liquid to
prevent the gas passing under the drum.
Fig. 8 shews the brushes 5 in number, placed virtically over each
other, but they may be placed horizontally to each other with only
sufficient elevation, the one over the other, for the liquid to pass from
the highest to the lowest brush, and the number of brushes may be
increased or diminished, and their dimensions altered according to the
quantity of gas to be purified, but I prefer to have the brushes placed,
as shewn on the Drawing. The fibre of which the brush is made should
not be too fine, whalebone such as is used in stable brushes does very
well, and it must be fixed by a suitable cement which is not acted
on by the solvent properties of the gas. A continuous band is fitted
zig-zag round driving pullies carried on the shafts that pass through the
drums, and at such end or at both if thought desirable pass through a
stuffing box formed in the end of the vessel, by which when the band
is moved motion will be given to the drums, which should be a slow
motion of 2 revolutions more or less per minute; but this may be
increased according to the quantity of gas passing through.
It is desirable in the case of imperfect condensation to pass the gas
through a vessel constructed and generally known as Anderson's washer

page_text: before it enters the brush washer just described, and a part of which is
shewn at E, Figs. 8, 9, and 10.
Fourth. Improvements in the Construction of Wet Purifiers or
Washers. These wet purifiers are not intended to be charged with any
substances that throw down a precipitate, such as chlorides of the metals
as lime does, but for such liquids as maintain within them in solution
the impurities which they extract from the gas, or that drive certain
impurities forward to other purifiers, while they retain a portion in
solution, as ammonia, and some other alkalies and sulphuric and some
other acids do. The vessel is shown at Fig. 13, being a plan through
the line F, G, Fig. 12.
Figure 12 is a vertical section through the line H, I, in plan with an
elevation of a similar vessel, Fig. 11, placed over it on columns or other
supports for the economization of ground room, and other reasons to be
more particularly referred to when I come to treat of the manner of
working these vessels in the purification of gas. The gas is caused to
enter at the upper surface of the lower dash plate which is in many
respects similar to the dash plate in an ordinary wet lime purifier which
is well understood; but instead of entering at the centre of the vessel
and issuing at the circumference the gas is caused to enter at the
circumference, pass all round, and from thence down through the dash
plate which is perforated with numerous small holes which need not be
more than 3 or th of an inch in diameter. Thence it flows under
the dash plate, being again numerously broken up into small particles
by projections formed on the under side of the whole of the dash plate,
one portion of which is shewn on plan at J, Fig. 13, turned upside
down. The gas thus finds its way to a central chamber into which it
passes, and the walls of which chamber form a central bearing to the
girders which support the lower dash plate, as well as the next above it,
and to a convex hood, all shewn in the section, Fig. 12.
the
The gas having found its way to the centre passes upwards within the
central chamber and thence radiates outwards to the circumference,
where it is once more broken up into small particles by passing up
through numerous holes cut in the outer portion of the second dash
plate; thence, it passes up and again finds its way to the centre, this
time passing immediately under the cover of the purifier and off at the
outlet on top at one or more pipes, as may be desired. Each of these

page_text: dash plates may or may not have projections formed on their lower
surface, as may be found requisite, and the gas after having gone
through this vessel may at once pass to the station meter or to
another purifier according to the system of purification that has been
adopted.
The vessel is charged with a fluid up to each dash plate so that the
gas has to pass through that fluid in its passage from the inlet to the
outlet of the vessel.
Exterior pipes and valves are provided for running off the fouled
liquid from the lower vessel, for running the liquor of the middle
portion into the lower, and the upper into the middle portion.
The upper portion may be served with liquid from a tank above, and
descend from thence to the next portion below; thus the foul gas will
enter the foulest liquid and pass out through the cleanest, or in some
instances a constant or intermittent stream may be run in at the top,
finding its way through pipes always open, and communicating between
the several compartments of the vessel, as is now done in some
washers.
The arrows show the direction which the gas is made to take on
entering beneath the first or lower dash plate at the circumference, and
issuing at the top in the centre, and to effect this, it necessarily follows
that the several horizontal compartments into which the vessel is divided
must cach be constructed water-tight, so that water or fluid cannot
pass from a higher to a lower one, except through the pipe passages
provided for that purpose; it also follows, that the compartments for
the gas must be made gas-tight so that the gas cannot flow unless under
the several dash plates, as shewn.
Fifth. Improvements in the Construction of Dry Purifiers.-These im-
provements consist in making them very much deeper than they usually
are, putting in a much greater depth of purifying material than is usual
by which three or four times as much gas can be purified in one vessel
as has hitherto been the case, and occupying proportionately less ground;
also in reducing the size of the hydraulic sealed cover in purifiers of large
dimensions, which makes it much easier to lift while giving abundant
space for the men to discharge and charge the purifier.
Figs. 14, 15, 16, and 18, shew various views of how one or other of
those improvements are effected.

page_text: Figure 14 shews a vertical section, and Figure 15 a plan of such a
purifier, and as such improvements are chiefly intended for gas works of
the largest magnitude, or where ground is scarce; the purifier is shewn
of the dimensions of thirty feet in diameter, and calculated to hold as
much purifying material as will purify one hundred million feet of gas
to the extent of purification that is usual at one operation.
The purifier is fitted with twelve trays for purifying material in the
usual manner, but as the total weight of the purifying material when
fouled or saturated with impurities when using oxide of iron, will amount
to 600 tons, the trays are borne on columns and girders, chiefly obtaining
their support from the bottom of the vessel, which I prefer should be
made of masonry or concrete, and finished on the upper surface in
cement, and thus made gas and water-tight, but the bottom may be
made of iron as is usual.
The girders for supporting the trays are so constructed that every
alternate one is securely fastened to the sides of the purifier to give
great strength to the whole and make it next to impossible that it can
alter its form, while every alternate one can be lifted out, as is now
usual with the whole of the girders, and thus much less labour will be
required, while ample room is provided for the men doing their work.
The columns which support the tray girders are carried up to and
attached to the under side of the roof of purifier, to which they afford
support.
The tray supports, shown in plan, within the circle of the columns
are wholly removed when cleaning out the vessel, by which a
central passage is formed through which the material can be passed.
The stream of gas is shewn divided into two, one being let in at the
bottom the other at the top, see Fig. 14, and both streams meet in the
middle of the purifier and there unite and pass off at the outlet K,
which may be at one or more pipes, as may be desired.
When the layers of purifying material on the three lower trays or on
the three upper trays, being in each case as much depth of material as is
usually put into a purifier, has become fouled, it will give an increased
resistance to the gas passing through it and will have become inert.
The valves to admit the gas to the fourth tray from the bottom and the
fourth from the top are now to be opened, on which the increased
pressure will be found to diminish, and the vessel is to be worked until

page_text: the last six trays or middle half of the material has become fouled, when
the gas will be turned into another purifier, as is usual with purifiers of
ordinary depth and construction.
A purifier so constructed will therefore purify double the quantity of
gas for the same amount of surface that an ordinary purifier will, from
the fact of the stream of gas being divided into two, each obtaining the
whole surface of the purifying material, but it will purify four times the
quantity of gas that an ordinary purifier will do for the same amount of
ground occupied by the aid of the two valves which admit the gas to
the middle half of the vessel after the portion at top and bottom are
saturated or fouled.
By the increased pressure which the fouled material gives, also by the
reduced temperature of the gas, as also by chemical tests in the ordinary
manner will be found the proper time to shut off the purifier from the
passage of the gas.
It has hitherto been usual to have the purifier lid of dimensions
slightly larger than the upper surface of the purifier.
Before the purification of gas was so well understood as now, noxious
gases were given off from the fouled material and it was necessary in
the interests of the men to have the lids of the full size of the purifier
to give them fresh air and prevent them being suffocated; but since the
quantity of gas manufactured has become so great that these vessels
are already made of 30 to 50 feet in diameter, the lids have become so
heavy that they amount in weight to several tons, and expensive lifting
gear of great power has to be provided, which may be only employed
for a few minutes once or twice in a week, thus involving, from its lying
idle, a waste of capital. Moreover, in any well regulated gas works
now the chemistry of gas is sufficiently understood to prevent any but
the slightest smell passing off from the purifiers, the noxious gases
having being previously removed in the ordinary scrubber, or in such a
vessel as that seen in Figures 8, 9, and 10, or fixed in the material used
in the dry purifiers now being described. It is therefore no longer
necessary to have the lids larger than is requisite to give light and air to
the men, and enable them to put the material into and remove it from
the purifier. The lid for the improved purifier therefore is shewn of the
size to suit an opening of only 10 feet in diameter or such a size as
will be sufficient for the removal of the contents of the purifier.

page_text: The Drawings shew the trays at the distance I consider best when
using metallic oxides in purification, but they may be put at greater
or lesser distances if thought desirable, or when other substances, such
as lime, are employed.
The material may be hoisted through the top, or it may be sent
through doorways in the sides of the purifier, as many as may be con-
venient, each fitted with a gas-tight door, and the purifier may also
be charged through those same doorways.
These purifiers may be solely above the ground, as purifiers usually
are, or they may with the revivifying house, to be afterwards described,
be sunk either wholly or partly in the ground, as gasholder tanks now
are, and they may be built of masonary or in iron, as may best suit each
locality.
Fig. 16 shews the gas admitted at 3 places and always passing up
through the purifying material, the lower valve being first opened and
the others in succession as the material becomes foul, as already
described for purifier shewn at Fig. 14.
Figs. 20 and 21 show a rhomboidal form of purifier without any
moveable water lute, but having a number of doors in lieu of a
removable cover; the trays are set at such an angle as may be considered
best for the material employed; and the vessel is divided vertically into 3
separate gas-tight compartments, so that any one may be shut off and
cleaned out while the rest of the purifier can be in action; and the gas
may be passed first through one part of the vessel and then through
other sections of it by pipes and valves, as may be desired.
Openings with luted doors are provided at each side, those on the one
side for discharging, those on the other side for pushing through the spent
and for the introduction of fresh material. It will be found convenient
to divide this vessel in its length by internal vertical partitions at such
convenient distances as will enable them to have bearers fixed to them,
on which to rest the trays that support the purifying material. Such
partitions will give strength to the vessel, and should have numerous
holes cut in them to permit the gas to circulate freely in the lower
portion of each compartment before it passes up through the purifying
material, and as shewn at Fig. 20. The gas may be passed into and out
of each of the three compartments into which the vessel is divided, as
shewn, or it may only pass into one at a time, and thence into the others,

page_text: girders resting one end in the wall of the building the other in a step
formed on the side of the purifier.
The slope to which these floors may be built should be a little below
the angle of repose at which the material will lie, they are shown to stop
short of both the outside wall and the purifier, thus leaving a space,
down which the material can be shot both in filling the floors and in
the process of revivification.
These floors may slope towards the purifier, as in Fig. 16, or from it,
as in Fig. 14, or if thought more convenient in any instance they may
be level and have trap doors in them, through which the material can
be passed.
A series of platforms outside the houses serves the men to stand on
while pulling or pushing the upper strata of revivified material through
the openings in the floor to the basement.
The floors round the purifier should be of sufficient capacity to contain
a charge for one purifier, so as to save second handling.
The roof of the house will contain a number of openings or dormer
windows, up through which the material will be hoisted when a purifier
has to be charged, and a space for ventilation at top, as shewn,
which from the form of the house will cause an inflow of an upward
current of air that will hasten the process of revivification, while it will
carry the effluvia high over the heads of people and disperse it in the
atmosphere, the lower doors of the building as well as the windows
round the platforms to have means of admitting or closing out the air,
and so as to regulate the same.
When the material is discharged through the top, and the floors
sloping as in Fig. 16, it will be convenient to have a tramway revolving
on a circular railway, the outer end of which tramway will describe a
circle round the purifier, on which a waggon will run, delivering the
materials to every part of the floors below, see Fig. 18.
The manner of filling the different floors will be by filling the lower
one first, and so on in succession to the uppermost, shutting off the
space between the floor and the wall before each one is filled.
The lower floor space of all is for the revivified material, and should

page_text: be of sufficient depth to
at equal distances from
hold a charge, from the four doors of which
each other it can be filled for conveyance
above, and its floor may either be at the general level of the ground
or it may be sunk in the ground where the purifiers arc, as before
described.
When the floors are sloped as shewn as in Fig. 14 it may not be
necessary to have the revolving railway, but the spent material may be
hoisted up through the top and shot direct, and allowed to fall on the
several floors; or it may be sent through openings formed in the
vertical sides of the purifiers on to those floors, and the same may take
place where the floors are set level, or where the floors are level one
above the other.
The spent material may also be hoisted up through the top and shot
on to any of those floors through trap doors formed in each floor for
that purpose.
Also in all those cases, whether the floors slope to or from the
purifiers, or are level, the floors may be supported at the inner end by
the purifier as shewn, or they may be supported in some independent
manner, and clear of the purifier or not, as may be desired.
In carrying out these improvements I prefer,-
First. Retort Houses.-In laying out new works I select a portion of
the ground offering the greatest advantage for extending the ranges of
retorts as described, taking care to place no permanent buildings in the
way, leaving a large open space all round the retort house for the
placing of coke, as well as in some places for the storing of coal.
I prefer that the whole of the purifying apparatus (with the exception
of the slow condensing pipes carried along the walls and through the
retort house) shall be placed at the most convenient extremity of the
ground, and in working them I proceed as follows:-The gas being
properly condensed as before described and freed from all tarry matters
is introduced either into the brush washer, Fig. 8, or into the wet
purifier or washer, Fig. 11, where it will be treated with pure water or
with ammoniacal or other suitable liquid, or by both, always finishing
with pure cold water so as to extract the last vestiges of ammonia
before the gas enters the oxide of iron or other such purifiers. According
to the quality of the ammonia employed in these vessels so will be the

page_text: quantity of carbonic acid and sulphuretted hydrogen, and other com-
pounds of sulphur that will be removed by those vessels from the
gas.
By preference common ammoniacal liquor and pure water to finish
with should be employed in the first vessel or vessels; this will take out
a large quantity of CO2 and SH2.
Afterwards the gas should be passed through a similar vessel or
vessels charged with ammoniacal liquor, from which CO2 and SH2 has
been removed, but especially the former, in other words containing free
ammonia, in which the whole of CO2 will be removed in this vessel or
vessels, when the gas should be sent into a third vessel also containing
free ammonia, which will be converted into a sulphide of ammonium,
in which state it will remove the other compounds of sulphur not being
SH2, when the gas may be forwarded to the last vessel an oxide of iron
purifier, where the final purification will take place from the only
impurity contained, namely, SH2.
The ammonia to be used in those vessels may be obtained from the
ammoniacal liquor made in the process of condensation, and from that
made in the first washer and scrubber, and the free ammonia may be
obtained by the process of Mr. Hill's, of Deptford, namely, by heating
the liquor in a vessel and driving off the CO2 and $ H2 through an
oxide purifier, where the S H2 will be fixed and the CO2 liberated and
thrown away until such time as a profitable use can be made of it, or
the heat for doing this may be obtained from the waste hot gases
passing from the retort furnaces, in either case taking care that the
gases and vapours passing off by the heating process are sufficiently
cooled before entering the oxide purifier to condense all the ammonia
before it enters that vessel.
When it is desired to continue the use of lime for the removal of
CO2, and the other compounds of sulphur not being S H2, and finishing
by the use of oxide to remove $ H2 the process of purification may be
as follows:-The whole of the gas after condensation may be passed
either through the brush washer or the wet purifier, or through both in
the order here stated, and may be passed through common ammoniacal
liquor, purified ammoniacal liquor, and lastly, through clean water, or
by preference through all three liquids, beginning with the common.

page_text: ammoniacal liquor of the gas works, either in vessels, Figs. 8 or 12, and
finishing in one of those vessels with purified ammonia first and clean
water last, when the gas may be sent into the ordinary dry lime purifiers
by preference worked in the manner described in the Patent of
R. H. Patterson, namely, that the first lime purifier or purifiers shall be
devoted to the removal of CO2 only; that the S H2 driven out by the
CO2 shall go forward into the next lime purifier or purifiers and convert
it into sulphide of calcium, when the sulphur impurities not being S H2
will be removed; thence the gas will pass into the dry purifiers, Figs. 14
or 16, whichever of these may be adopted, where the purification will be
completed by the removal of SH2. By the adoption of these various
means space and the expenditure of material may be greatly diminished,
thereby decreasing the capital to be employed, while from the arrange-
ment of the different parts, manual labour is so considerably reduced
that the gas produced through the agency of these improvements may be
supplied far more economically than has hitherto been the practice.
Having now described and particularly set forth the nature of this
Invention and the manner in which the same is or may be used or
carried into effect, I would observe in conclusion that I do not confine
or restrict myself to the precise details or arrangements which I have
described or referred to, as variations may be made therefrom without
deviating from the principles or main features of this Invention; but
what I consider to be novel and original, and therefore claim as my
Invention is,-
Firstly. The construction of retort houses in such a manner as will
allow of the greatest number of retorts being set within a given area,
and thus economize space and material, as herein described and shown
on the Drawings, Figs. 1, 2, and 3.
Secondly. In forming condensers so that one, two, three, or more
portions of the apparatus may be employed at one time, as and for the å

page_text: Fifthly. In the construction of dry purifiers, whether for oxides of the
metals or lime, as herein described and shewn on the Drawings, as
Figs. 14, 15, 16, 18, 20, and 21.
Sixthly. In the construction of purifying houses, as herein described
and shewn on the Drawings, as Figs. 14, 15, 16, 17, 18, and 19.
In witness whereof, I, the said George Anderson, have hereunto
set my hand and seal, this Twelfth day of August, in the year
of our Lord One thousand eight hundred and seventy-five.