Improvements in or connected with the Manufacture of Acetic Acid, and in Apparatus therefor.
Year: 1889

page_text: Date of Application, 22nd Aug., 1889
Complete Specification Left; 13th May, 1599-Accepted, 14th June, 1890
PROVISIONAL SPECIFICATION.
Improvements in or connected with the Manufacture of Acetic Acid,
and in Apparatus therefor.
I, JOHN FARMER, of 147 St. Andrew's Road, Pollokshields, Renfrewshire;
Engineer, do hereby declare the nature of my invention to be as follows
-
My Invention has reference to improvements connected with the manufacture of
acetic acid, and consists especially in the arrangement and combination of the
parts of apparatus for the distillation of acetic acid from any of the acetates most
commonly used, such as the acetate of lime And the object of the Invention is
to produce acetic acid in a purer state and in a simpler and more efficient manner
than heretofore.
rr
To effect this, I form in the inside of a metal or other pot or still, near to the
top, a cavity, recess, or gutter capable of holding any suitable purifying liquor,
and I place over the still and partly over this recess or gutter, a cover or lid of
gun-metal, stone, or other suitable material which will resist the action of the gas,
having its edge or rim turned down to dip a few inches into the liquor, which
forms a seal" through which the vapour as it ascends from the still below must
pass under the turned down edge before it reaches to the top part of still above
the sealing cover, which is closed in by a usual upper stone or other cover, to the
top of which cover, a copper, delf, or other suitable pipe is Inted to convey the
gas direct to the condenser, from whence it issues as finished commercial acetic
acid. The gas
in the still under this last cover referred to (after it has passed
through the seal) being in free communication with the atmosphere through the
condenser, and it having little or no pressure, a putty or clay joint is all that is
required to keep this cover tight; thus the trouble, expense, and waste through leakage,
of keeping the large still cover tight under the pressure of an acid gas, as when still's
are used with the old style of small purifiers or traps placed outside and independent
of the still, is entirely avoided. The liquor in the gutter of my still from its position
inside is kept heated sufficiently by the gas from the still itself, and the necessity of
keeping the purifying liquor heated by extra heating pipes or steam jackets, as here-
tofore, is dispensed with. I screw an open-mouthed stand pipe from the outside of the
still up through the gutter, and reaching a little above its top, for emptying or
reducing the liquor within it; this I do by screwing the pipe downwards the distance,
according to the amount of liquor desired to be drained off. The liquor-so run off
may he let direct into still through a pipe fitted near to bottom of still, but having an
open mouth directly under the draining pipe, or the liquor may be run into a separate
vessel for subsequent use. The still is provided with door or doors at bottom for
drawing the residual charge after acid has all been extracted and should also have
glass sight holes or gauges to ascertain height of charge in the still. The still
may be heated by an open fire, but preferably by a steam copper coil placed
inside, with suitable steam cocks and condensed steam connections.
To prepare the still for starting, a charge say of common acetate of lime and
muriatic acid is introduced into the still at an opening or door near top. The charge
should cover the heating coil. A purifying liquor composed of a mixture of a very
pure acetate of lime and marine acid and having the tar carefully skimmed off, is run
into the gutter through a suitable opening in the top cover and forms the
seal ".;
and should it be important, for instance, to remove most of the tar from the acetic
acid being distilled, paraffin wax may be put into the outer division of the "seal" in
gutter and will float on the top of the liquor already introduce.l. Paraffin wax makes
64
a good separator for the tar and has been worked in these old outside and separate
purifiers or traps already referred to, but with in different success owing greatly to the
:

page_text: choking up of pipes and difficulty of cleaning and recovery of the paraffin. The large
area of this new purifier causes a slow speed of the gases passing through it, and the
absence of small pipes allows this purifying agent to be easily used when desired.
Other purifiers than those named may be used in this new or improved trap the nature
of which will depend upon circumstances. Steam being admitted into the coil, acetic
acid gas is liberated from the "charge" and passes up and through the purifying
liquor in the trap, thence by the large pipe to condenser, all as before described.
To expedite the process of distillation, towards the end it is a common practice to
inject live steam directly into the still as near to bottom as possible; this is generally
done through an open-mouthed copper pipe fitted in still, but this does not permeate
the mass sufficiently owing to the steam being confined to one part. When the pipe
is perforated with small holes to distribute the steam, these holes very often choke up
during the time they are lying in the still out of action. To remedy this I screw to
the side of still at bottom, a small gun-metal stuffing-box of say one or two inches
diameter, which has a round pin passing through it tightly with a head on the
inside to prevent it being drawn out accidentally from still and stuffing-box, and
outside of the stuffing-box a stop is inserted to prevent it being accidentally pushed
inwards; the point of the pin projects a few inches beyond the stuffing-box and is
screwed about a quarter of an inch or so less in diameter than the body. A copper
pipe a little longer than the diameter of still and of the same external diameter as the
pin, is prepared by having its surface perforated with small holes nearly its whole
length, and the open end of this pipe is screwed to fit the screwed part of the pin
above mentioned, while the other end has a coupling and india-rubber steam hose pipe
attached to it. When live steam is required to be let into the still this perforated
pipe is simply screwed on to the end of pin and pushed through the stuffing-box and
charge in the lower body of the still and the steam being turned on now passes up
through the perforations and charge in the still; and the pipe can be drawn
backward and forward from time to time.
It will be seen that instead of the top stone cover going right across the still, narrow
segments of stone, fireclay, or other equivalent may be jointed over the upper edge
of the still, and the outer top edge of trap which forms the seal; when this is done
the gas is taken from the outer diameter of the still just over the seal and not from
the centre of the still as may be done in the first arrangement.
Dated the 21st day of Anonst 1400
COMPLETE SPECIFICATION.
Improvements in or connected with the Manufacture of Acetic Acid,
and in Apparatus therefor.
I, JOHN FARMER, of 147 St. Andrew's Road, Pollokshields, Renfrewshire, Engineer,
do hereby declare the nature of my invention and in what manner the same is to
be performed to be particularly described and ascertained in and by the following
statement in writing, reference being had to the accompanying four Sheets of
Drawings, and to the letters and figures marked thereon, that is to say
:
My Invention has reference to and comprises improvements in and connected with
the manufacture of acetic acid, and consists especially in the arrangement and com-
bination of the parts of apparatus for the distillation of acetic acid from any of the
acetates most commonly used, such as the acetate of lime. And the object of the
invention is to produce acetic acid in a purer state and in a simpler and more efficient
manner than heretofore."
And in order that my said invention and the manner of performing or carrying the
same into effect or practice may be properly understood I have hereunto appended:
four explanatory Sheets of Drawings in which the same reference letters are used to
indicate corresponding parts in all the figures where shown.
1 . ,
Figure 1 on Sheet 1 is a sectional elevation, and Figure 2 on Sheet 2 a' plán

page_text: corresponding to Figure 1, both showing an acetic acid still as constructed in
accordance with my invention and embodying and illustrative of one arrangement
and combination of the improvements thereof. Figures 3 and 4 on Sheet 3 are
respectively a sectional plan and a sectional elevation of another modification, or
arrangement and combination of the parts of an acetic acid still and improvements of
my said invention, from that shown in Figures 1 and 2. Figure 5 on Sheet 4 is a
sectional elevation showing the application of my improvements to an ordinary acetic
acid still.
Referring to Figures 1 and 2, A is the lower body of the still, preferably formed
of cast iron, and cylindrical in shape, lined internally at A' with segmental fireclay
tiles or bricks or other equivalent to resist the action of the distilled off acid vapours
or gases, especially at the upper part of the still A. B B2, is the steam heating worm.
coil pipe fitted in the lower part of the vessel for heating and boiling the material
under treatment; and C C¹ are the pipes for drawing the distilled off vapour or gas
from the top, and leading it down through the condensing worm D fitted within the
cold water condenser D₁, which may be of any ordinary construction, supplied by.
water from the pipe D" from any overhead source of supply and run off by the over-
flow branch D².
By my improvements I form in the inside of the metal or other equivalent close
heating pot or still A, near the top and outside, a cavity, recess, or gutter chamber a
below and rising above the top A" of the still vessel A, and either jointed at a¹ as
shown in Figure 1, or formed in one with the outer case A of the still, as shown in
Figures 3 and 4, and preferably annular as shown in the Drawings, capable of holding
any suitable purifying liquor filled into it at a" below the top A" of the body of the
still A, and I place over the still and partly over this recess or gutter a a cover or
lid 6 of gun-metal, stone, or other suitable material, which will resist the action of
the gas, and supported at its vertical lip b' on bricks or other equivalent at 6", and
having its lower outer edge or rim 6' turned down to dip a few inches into the said
liquor, which forms a seal" through which the vapour or gas as it ascends from the
still below must pass under the turned down edge and through the liquor a" before it
reaches to the top closed in part A2 of the still A, above the said sealing cover band
which is closed in by a usual upper stone or other cover A³ jointed over the whole
top at A as shown in Figures 1 and 2, or it might be only over the outer annular
part a as hereinafter described in reference to Figures 3 and 4. To the top of this
cover A³, a copper, delf, or other suitable pipe C is luted to convey the gas distilled
off direct by the knee branch C¹, to the worm D of the condenser D', and from the
lower part of the worm D, it issues as finished commercial liquid acetic acid at D*..
The gas in the still A under this last upper cover A³ referred to (after it has passed
through the sealing cover b and liquid a¹) being in free communication with the
atmosphere through the condensing worm D, and it having thus little or no pressure
outside the seal and lip of the cover b, a putty or clay joint at A is all that is
required to keep this cover and its gas pipe C tight, thus the trouble, expense, and
waste through leakage of keeping the ordinary large still covers tight under the
pressure of an acid gas, as when stills are used with the old style of small purifiers or
traps placed outside and independent of the still is entirely avoided. The liquor a¹¹
in the gutter a of my still A from its position inside is generally kept heated
sufficiently by the gas from the still itself, and the necessity of keeping the
purifying liquor heated by extra heating pipes or steam jackets as heretofore
inay be dispensed with, or, when desired it might be heated by a single steam coil
pipe Figure 1 taken by a branch from the main supply steam pipe B', leading
the steam to the heating worm B. I screw an open-mouthed stand or drawing
off branch pipe c¹ from the outside of the still up through the sealing gutter or
chamber trap a and reaching a little above the level for emptying or reducing
the liquor within it; this I do by screwing the pipe downwards the distance,
according to the amount of liquor desired to be drained off from, or level to be
maintained in the trap a. The liquor so run off may be let direct into the still

page_text: through a branch pipe c" fitted near to the bottom of the still A, but having an open
Diouth directly under this draining pipe ', or the liquor.inay be run into a separate.
vessel for subsequent use. The still A is provided with door or doors C" at bottom.
for drawing off the residual charge after acid has all been extracted, and would also:
have glass sight holes or gauges at C² to ascertain the height of charge in the still.
The still A may be heated by an open fire, but preferably by the steam copper.
coil B B2 placed inside, with suitable steam cocks and condensed steam con-
néctions B B and drawing off condensed water pipe B¹¹. To prepare the
still A for starting the distillation, a charge say of common acetate of lime. and:
muriatic acid is introduced into the still at the opening or door pipe E near the top
fitted with a portable closing lid E'. This charge should cover the steam heating
coil B to about the level indicated at e. A purifying liquor composel preferably of
a mixture of a very pure acetate of lime and marine acid and having the tar carefully
skimmed off, is run into the trap gutter a through a suitable plug opening at a² in
the top cover A³ to form the "seal" with the inner cover b, through which the gas
has to pass, in escaping to the pipes C C¹ and condensing worin D, and should it be.
important, for instance, to remove most of the tar from the acetic acid being distilled,
paraffin wax may be put into the outer division of the "seal" in gutter a and will
float on the top of the liquor already introduced on the outside A2 of the cover bas
indicated at a Figure 1. Paraffin wax makes a good separator for the tar and has
been worked in these old outside and separate purifiers or traps already referred to,
but with indifferent success owing greatly to the choking up of pipes and difficulty
of cleaning and recovery of the paraffin. The large area of this new purifier causes a
slow speed of the gases passing through it, and the absence of small pipes allows this
purifying agent to be easily used when desired. The use of the mixture of acetate of
lime and muriatic acid, paraffin, or other equivalent liquid with this mode of trapping
the gases at the top a of the still relieves the pressure on the escaping gas and enables
the distillation to be continued for much longer periods than heretofore without
removing the tops of the stills. Other purifiers than those named may be used in
this new or improved trap a the nature of which will depend upon circumstances.
Steam being admitted into the coil B B² acetic acid gas is liberated from the "charge"
and passes up and through the purifying liquor a" in the trap a thence by the large
pipe C, C to condenser D D, all as indicated by the arrows in Figure 1 and
as before described.
وو
To expedite the process of distillation, towards the end, it is a common practice to
inject live steam directly into the still as near the bottom as possible; this is generally
done through an open-mouthed copper pipe fitted in still, but this does not permeate
the mass of acetate of lime sufficiently owing to the steam being confined to one part.
When the pipe is perforated with small holes to distribute the steam, these holes very
often choke up during the time they are lying in the still out of action. To remedy
this I joint and screw to a branch A at the side of the still A at bottom, a flanged
gland gun-metal stuffing box f, of say one or two inches diameter shown in separate
end view in Figure 2 A Sheet 2 and which has a round pin f passed liquid tight
through it, with a head on the inside to prevent it being drawn out through the
stuffing-box, and outside of the stuffing-box a stop or cotter f is inserted in the
pin "to prevent it being accidentally pushed inwards; the point of the pin f¹ projects
a few inches beyond the stuffing-box f, and is screwed about a quarter of an inch or
so less in diameter than the body. A copper pipe fa a little longer than the diameter
of still A and of the same external diameter as the pin ", is prepared by having its
surface perforated with small holes nearly its whole length, and the inner close end of
this pipe is screwed to fit the outer screwed end of the pin f', while the other outer
open end of the pipe has a coupling and india-rubber steam hose pipe f³ attached to
it, led from the main supply steam pipe B', fitted with a stop valve or cock B. This
perforated pipe is shown in its outmost position in Figures 1 and 2 and in its inner
acting position in Figures 3, 4, & 5. When live steam is required to be let into the
still A this perforated pipe f is simply screwed on to the end of the pin and pushed

page_text: through the stuffing-box and charge of material in the lower body of the still, and
the steam being turned on by the valve B³ now passes up through the perforations in
the pipe, and charge in the still; and the pipe 2 can be drawn backward and
forward from time to time. The lower coils B2 of the steam heating worm B B
where they lead to the drain pipe B are undulated and fitted in the form of a horse
shoe, as indicated in dotted lines in Figure 2, so as to allow of the perforated steam
pipe being inserted and withdrawn as described.
Referring to the acetic acid still shown on Figures 3 and 4 on Sheet 3; the main
improvements in this still are all substantially the same as described in reference to
Figures 1 and 2, and lettered to correspond, so that I need now only describe the
features of the improvements of this modification in so far as they are different from
Figures 1 and 2. In this arrangement the annular liquid trapping chamber a is
shown as formed or cast in one with the upper part of the body of the still A; and
made wider and all lined with segments of firebrick a* on the inside and covered at
the upper top A" of the body of the still A, with segmental fireclay blocks Ax. The
trapping rim in this case is formed as a deep annular ring resting on bricks at b
with interstices between then for the escape of the gas in the centre of the trapping
chamber a, and is also lined on both sides with segmental fire bricks or blocks b*, to
protect the iron from the corrosive action of the gases, and has an annular stepped or
Hanged part near the top at 6 on which a permanent stone or other cover A³ is jointed
nearly level on the top with the outer flange A.
Thus it will be seen that instead of carrying the top stone cover A³ right
across the still A, narrow segments A³ of stone, fireclay or other equivalent are
jointed over the upper outer edge of the cover A³ and the flange A at the
top of the trapping chamber a to cover the outer annular top part of this trap a,
which forms the seal; when this is done, the gas is taken from the outer
diameter of the still A, by the branch C and pipe through a hole in one of the
slabs As, just over the outer part of the seal as shown particularly on the right of
Figures 3 and 4 and not from the centre of the top A³ of the still as shown in the
first arrangement, which thus dispenses with the necessity of removing the large
cover A³ as in Figures 1 and 2, as the trapping annular chamber a can be cleaned
out from time to time by merely lifting out the small segmental tiles A over this
chamber a. In this arrangement the acetate of lime and muriatic acid, or other
material to be treated is filled into the still A through a central hole or deor E" in
the stone top A³ covered in by a portable fireclay or other block E2 jointed over this
door E. The drawing off branche is shown as inserted laterally through a stuffing
box in the bottom of the trap chamber a formed with a sight glass at c, so that
this branch may be turned upwards to observe and regulate the level of the liquid a¹
in the trap a or to fill in the liquid or be turned downwards to any angle to draw off
the trapping liquid to any level when desired.
Referring to Figure on Sheet 4, this shows the application of my improvements
to an ordinary acetic acid still A. In this arrangement an additional piece B₁ is
fitted and bolted by flanges B' to the top of the still A, and the trap wall is formed by
adding a conoidal rim a of copper, brass, or other sheet metal screwed liquid-tight
between the said flanges B5 of the top piece B and still, and the luting or trapping
arrangement is formed by cementing and securing a correspondingly formed conoidal
rim in a groove at in the upper cover stone, and jointing the gas branch Cover
an opening in the cover above the escaping part A2 of the trap a, and in filling into
it the luting purifying liquid a", which in this case is preferably paraffin scale,
through the plug hole a over this said recess A² at the opposite side of the gas
drawing-off pipe C. For ensuring that the level of the paraffin or other trapping and
puritying liquid a" shall not flow over the upper inner lip of the trap a, a trap
drawing off branch c', c', is fitted by a liquid-tight screw gland or stuffing box, which
can be turned round or inverte from the position shown in Figure 5, to draw off all
the liquid from the trap A when désired. The perforated steam blowing off pipe/"
is in this figure fitted with a hollow pin on its inner end, and shown as inserted in
its inward acting position.

page_text: Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, 1 declare that what I
claim is.
First. The construction, or arrangement and combination of the parts of stills and
their fittings, for the distillation or manufacture of acetic acid, substantially as and in
the manner berein described in reference to and shown in the accompanying Drawings.
· Second. In stills for the distillation or manufacture of acetic acid, the construction
and use of a liquid trapping chamber and inner cover or division fittings round the
upper part of the body of the still, for causing the gas to pass through and be
purified, and relieving the pressure outside, substantially as herein described in
reference to and shown in the accompanying Drawings.
Third. In stills for the distillation or manufacture of acetic acid, the construction
and use of a portable perforated steam tube with stuffing box and fittings for its
insertion and withdrawal at the lower part of the still, substantially as and for the
purposes herein described in reference to and shown in the accompanying Drawings.
Dated the 12th May 1890.
W. R. M. THOMSON & Co.,
96, Buchanan Street, Glasgow, Agents.