CERTAIN IMPROVEMENTS IN PURIFYING COAL GAS, AND INCREASING ITS ILLUMINATING POWER, AND PREVENTING THE CIRCULATION OF IT BEING IMPEDED BY FROST
Year: 1844

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
MALAM, of Huntingdon, in the County of Huntingdon, Gas Engineer, send
greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Letters Patent under the Great Seal of Great Britain, bearing date at
Westminster, the Twenty-sixth day of September, in the eighth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said James Malam, my exors, adñiors, and assigns, Her especial
licence, full power, sole privilege and authority, that I, the said James
Malam, my exors, adñiors, and assigns, and such others as I, the said James
Malam, my exors, adñiors, or assigns, should at any time agree with, and no
others, from time to time and at all times thereafter, during the term of years
therein expressed, should and lawfully night make, use, exercise, and vend,
within that part of Her said Majesty's United Kingdom of Great Britain
and Ireland called England, Her Dominion of Wales, and the Town of
Berwick-upon-Tweed, my Invention of "CERTAIN IMPROVEMENTS IN PURIFYING
COAL GAS, AND INCREASING ITS ILLUMINATING POWER, AND PREVENTING THE
CIRCULATION OF IT BEING IMPEDED BY FROST;" in which said Letters Patent
there is contained a proviso that I, the said James Malam, shall cause a
particular description of the nature of my said Invention, and in what
manner the same is to be performed, under my hand and seal, to be inrolled
in Her said Majesty's High Court of Chancery within six calendar months

page_text: next and immediately after the date of the said in part recited Letters Patent,
as in and by the same, reference being thereunto had, will more fully and
at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
James Malam, hereby declare that the nature of the said Invention, and
in what manner the same is to be performed, are fully described and ascer-
tained in and by the present Specification thereof, reference being had to
the Sheets of Drawings. hereunto annexed, marked A, B, C, D, E, F, G, H,
that is to say:-
My Invention consists,--
Firstly, in an improved means of purifying coal gas from the sulphuretted
hydrogen with which it is commonly impregnated, and by which its illumi-
nating power is more or less impaired. Lime has been hitherto usually
employed for this purpose either in a wet or dry state; but as the lime
absorbs at the same time a certain portion of carbonic acid, which is also
present in the gas (becoming thereby converted into carbonate of lime), and
loses its capability of taking up the sulphuretted hydrogen in precisely the
same proportion as it becomes charged with the carbonic acid, it com-
¡monly happens that after a lime purifier has been a considerable in use it
ceases to absorb even the smallest portion of the sulphuretted hydrogen.
Now, my improvement consists in subjecting the gas to the agency of sulphate
of iron, commonly called green vitriol, before passing it through the lime puri-
fier. The sulphate of iron combines with the hydro-sulphurate of ammonia,
with which the sulphuretted hydrogen is always found in conjunction, producing
sulphate of ammonia and sulphuret of iron, and leaving the lime little more
to do afterwards than to absorb the carbonic acid. For this purpose I intro-
duce an apparatus, such as is represcuted in Sheet A of the Drawings
hereunto annexed, between what is commonly called "the washer" and the
lime purifiers, and which, for the sake of distinction, may be denominated the
"green vitriol-purifier."
Figure 1 is a perspective elevation of this. machine; Figure 2 a, top plan,
Figure 3, a front elevation, and Figure 4, a section of the body. part. of the
apparatus. A is case for containing the green vitriol, which is more or less
diluted with water, according as the gas is more or less charged with hydro-
sulphuret of ammonia. A good average proportion is one and, a, half of
green vitriol to one of water. The case being filled to near the top with this
solution, the gas is made to pass through, it on its way to the lime purifiers
entering by the pipe B and escaping through the opposite pipe. C.. D is, the
shaft of an agitator by which the vitriolic solution is kept in a continual whirl

page_text: into D, from which it escapes into the main service pipe G. The internal
arrangements of the cylinders, which are exactly the same in all four, are
particularly shewn in Figures 4, 5, and 6, Sheet C. H is an upright shaft
which is stepped at bottom in a boss K, formed in the bridge L, and passes
out at the top of the cylinder through a stuffing box I; M, M, M, are a
number of light wheels firmly keyed to the upright shaft II, one of which is
shewn in section in Figure 7, Sheet C; N, N, N, are scrapers jointed to pro-
jections upon the periphery of the wheels M, M, and acted on by the springs
0, 0, which cause them to press against the inner surface of the cylinder,
for the purpose to be presently explained. As the gas passes from the gas
holder through these cylinders, and comes in contact with their cold metallic
surfaces, the aqueous vapour contained in it is precipitated on the sides of
the cylinder in a number of icy particles resembling hoar frost. And in order
that this effect may be the more certainly produced, the cylinders are made
of more than double the dimensions of the inlet main E, which necessarily
retards the onward flow of the gas, and allows little, if any, of it to escape
without coming into contact with the sides of the cylinders. The ice, as it
accumulates on the sides, must of course be removed from time to time, and
to do this is the office of the scrapers N, N, N, before mentioned. A rotary
motion is given to them, when required, by means of the wheel gearing
exhibited in the Drawings. P, P, P, P, are bevil wheels fixed to the
upright shafts H, I, H, H; R, R, R, R, pinions on the laying shaft S which
drive the bevil wheels P; T and U shafts which drive the pinions R; and V,
a fly wheel which actuates the shaft U, and derives its own motion from some
convenient first mover. The ice, as it is scraped or loosened from the sides
of each cylinder, falls to the bottom, where there is a trap valve for its removal.
Thirdly, my Invention consists in still further desiccating coal gas after it
has been subjected to the preceding processes, and thereby still more improving
it in point of quality. For this purpose I cause the gas, after it comes from
the freezing cylinders, to pass through another set of cylinders, where it is
exposed to the absorbing action of alcohol (or any other strong spirit), and
which I call the spirit cylinders.
Figure 1, Sheet D, is an external elevation of these cylinders; and Figure 2,
a vertical section through the centre of the apparatus. A and B are the
cylinders which are mounted on a hollow basement C, which is separated into
two compartments by the partition D; H, H, are two upright standards
stepped in the bottom of the basement C, which carry three guide rings I, I, I,
placed at equal distances apart, a plan of one of which rings is given sepa-
rately in Figure 3; L, L, are two open spirit holders attached to the top

page_text: and presents an ever-changing surface to the passing volumes of gas; E, E;
are the arms of this agitator; and F, a stuffing box in the top of the chamber
through which the shaft D passes. Motion is given to this agitator by the
combination of means shewn in Figures 1 and 2. G is a cross lever which
is firmly secured to the top of the shaft D; II, II, two side rods which aro
connected at one end to the ends of the lever G, and at the other to the
upper ends of two small working beams I, I, which turn on axes fixed in the
framework of the chamber A; K, K, are two rods which connect the lower
ends of the two reciprocating working beams I, I, with two cranks L and M,
which are attached on the ends of a shaft N, which has its bearings in the
top of the case A; and O is a toothed wheel keyed to one end of the shaft N,
into which works a pinion P affixed to the end of another shaft R, which is
also mounted on the top of the case A, and carries on its opposite end the
fly wheel W. A rotary motion being communicated to the shaft R from
any first mover, it causes the cranks L and M also to revolve, and these impart
through the medium of the parts K, I, II, and G, a semicircular or alternating
motion to the shaft and arms (D.and E) of the agitator.
Secondly, my Invention consists in an improved means of freeing coal gas
from the aqueous vapours with which it is commonly charged, and preventing
any deposit thereof from impeding the circulation of the gas. During the
manufacture of gas from coal, there is always a large quantity of aqueous
vapour which comes off along with it from the retorts, to which considerable
accessions are afterwards sure to be made, either from the lime purifiers (if
on the wet principle) or from the water in the gas holder. The more of this.
aqueous vapour there is in the gas, the less is its illuminating power, and the
more smoky the flame with which it burns. The greater too is the risk.
of the pipes being stopped by the water becoming condensed and frozen. To
obviate these evils, I cause the gas, after it comes from the, gas holder, to pass
through a series of condensing or precipitating vessels called freezing cylinders,
constructed as represented in Sheets B and C of the Drawings hereunto
annexed.
Figure 1 (Sheet B) is an external front elevation of a series of these cylin-
ders; Figure 2, a plan thereof; Figure 3, a vertical section of the base of
the cylinders; Figure 4 (Sheet C), an external end elevation; Figure 5,
another vertical section, shewing more of the internal arrangements; and
Figure 6; a transverse section. A, B, C, D, are the freezing cylinders. The
gas is admitted. by the gas holder by the pipe E into the first cylinder A; at
the bottom from A it flows over at the top into B, descending which it passes
into C by an opening F (see Figure 3), rises to the top of C and flows over

page_text: its illuminating powers. V, V, are doors by which admission is obtained to
the inside of the cylinders, in order to adjust or renew the threads from time
to time. These doors are fixed by means of the pinching screws W, W,
which are screwed into the bridges X, X, which abut against the doors on the
outside, and are inserted at their ends into lugs Y, Y, projecting from the sides
of the cylinders.
Fourthly, and lastly, my Invention consists in certain improvements in the
valves and other parts of gas lime purifiers. These improvements are repre-
sented in Sheets E, F, and G, of the Drawings hereunto annexed.
Figure 1, Sheet E, is a sectional elevation, showing the construction of the
valves I employ and the means by which they are opened and closed; Figure 2
is a cross section on the line a, b, of Figure 1. A is the pipe leading from
the common washers which open into the lower division B of the valve chest.
The upper division C of the valve chest is subdivided into four compartments
D, D, D, D. In each of these compartments there is placed a valve E, of
the peculiar construction shewn in Figure 1, where it is represented both as
it appears when closed and when open. This valve is of a cylindrical form,
and is raised and depressed so as to be fixed in any required position by means
of a hand wheel W, which is fitted as a nut on to the top of the valve spindle,
which has a screw cut on it for its reception. G is an air-tight stufling box
through which the valve spindle passes upwards; I is a cup or pipe which
surrounds the openings which form the communications between the lower and
divisions of the valve chest, and must be equal in height to a column
upper
of water that will balance the pressure under which the gas may at any time
come from the washers. This cup is filled with water into which the valves
dip when depressed, forming thereby a hydraulic joint which prevents any
passage of the gas between the two divisions of the chest.
In Sheets F and G a complete set of purifiers provided with these improved
valve chests are represented; Figure 1 (Sheet F) being a ground plan;
Figure 2 (Sheet G) an end elevation in section; and Figure 3 (Sheet G)
an external elevation of the same. A, A, A, are the lime riddles, of which there
are five in each compartment; B, B, are the covers or lids which are made
air-tight by means of hydraulic joints, as represented at C, C, Figure 2. For
the sake of greater convenience in lifting off these covers when access is
required to be had to the purifiers in order to change the lime, the arrange-
iments separately represented in Sheet II of the Drawings hereunto annexed
are adopted. A, A, are coluinns which spring from the entablature of the
purifiers and support an intermediate rail C, on which runs a traversing block
or carriage D, from the lower end of which is suspended a screw jack E, by
means of which, when brought over any of the purifiers, the cover B can be

page_text: of the uprights II, II, consisting of two concentric chambers, the outer one
being much smaller than the inner; K, K, K, K, are lengths of cotton
thread, such as is used for wicks of lamps, which are drawn through rings
fixed at the bottom of the smaller of the spirit holders L, L, till the two ends
meet at an equal distance from the rings, the ends are then turned over the
edges of the spirit holder and drawn through the holes M, M, in the guide
rings I, I, I, reaching at bottoms to a little way below the undermost ring;
N, N, are two circular cups which surround the bottoms of the uprights H, II,
and communicate with one another by the horizontal pipe O; P is a force pump,
the induction valve of which opens into the pipe 0; Q is a pipe which leads
from the force pump to the top of the cylinders, where it communicates by
lateral branches with two close spirit reservoirs R, R, which have no other
communication with the rest of the apparatus, except through the pipes S, S,
and vent tubes T, T. Such being the construction of the apparatus, let us
suppose that the spirit holders L, L, are filled with alcohol to a little way
above the level of the under terminations of the vent tubes T, T, and that
the reservoirs R, R, are also partially filled with the same. The alcohol is
drawn up by the capillary attraction of the cotton threads K, K, out of the
holders L, L, and passes down those portions of them which are suspended
in the cylinders, keeping them constantly wet, and presenting large alcoholic
surfaces possessing great affinity for any aqueous vapours which may come in
contact with them. The alcohol which drops from the cotton threads is
collected in the cups N, N; and when it has accumulated there in a suflicient
quantity, it is pumped up by the force pump P into the close reservoirs R, R,
whence it flows down the pipes S, S, until the holders L, L, are again filled
to the level of the lower ends of the air tubes T, T, and as often as the
alcohol in the holder L, L, falls below the level of the air tubes T, T, the
air rushes up into the reservoirs R, R, and forces down a quantity of spirit
sufficient to raise the surface of the liquid in L, L, again above the level
of the lower ends of the air pipes T, T. U, U, are float valves, the spindles
of which are encased in glass tubes, by which the height of the alcohol in the
close reservoirs R, R, and consequently in the open holders, can always be
ascertained by inspection. The gas to be subjected to the action of the
alcohol is first admitted into the cylinder A through the pipe E, and ascending
to the top of that cylinder flows through a passage Fin the entablature into
the cylinder B, descending which it passes off into the main by the pipe G.
In making this circuit any aqueous vapour which may happen to be still
suspended in it is almost certain to be absorbed by the alcohol with which it
comes in contact; and should any portion of the alcohol itself become vapour-
ized, and pass off in combination with the gas, it can only tend to increase

page_text: laid hold of and lifted off. G is a hand wheel which is fitted on to the screw
rod II of the jack E, and by which it is raised or lowered; I, I, are studs
which project upwards from the covers B, and fit into recesses in the lower
end of the screw rod H, and are made fast there by means of a cotter
bolt J. The cover, when raised from its seat, is easily removed out of the
way by pushing the traversing block along the rail a little to one side or
other. The general result of the improvements described under this head is,
that much less space is occupied by the lime purifiers than usual, that there
are fewer bends in the pipes, that the valves are much less expensive, and
that this branch of the system of purification is altogether carried on with
greater dispatch and economy.
And having now described the nature of my said Invention, and in what
manner the same is to be performed, I declare that what I claim is,―
First, the purifying of coal gas from sulphuretted hydrogen by the applica-
tion of sulphate of iron or green vitriol to the purpose, as before described.
Second, the freeing of coal gas from aqueous vapours by means of freezing
cylinders, as before described, and thereby preventing the circulation of it from
being impeded by frost.
Third, the desiccation of coal gas by subjecting it to the action of alcohol or
any other strong spirit, as before described.
And, fourth, the improvements in the valves and other parts of lime purifiers,
before described.
In witness whereof, I, the said James Malam, have hereunto set my
hand and seal, this Twenty-sixth day of March, One thousand eight
hundred and forty-five.
AND BE IT REMEMBERED, that on the Twenty-sixth day of March, in
the year of our Lord 1845, the aforesaid James Malam came before our said
Lady the Queen in Her Chancery, and acknowledged the Specification afore-
said, and all and every thing therein contained and specified, in form above
written. And also the Specification aforesaid was stamped according to the
tenor of the Statute made for that purpose.