Improvements in Apparatus for Concentrating Sulphuric and other Acids.
Year: 1891

page_text: Date of Application, 14th Nov., 1891
Complete Specification Left. 12th Aug.. 1892-Accepted. 12th Nov.. 1892
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Concentrating Sulphuric and other
Acids.
I, CHRISTOPHER JAMES SCHOFIELD of Clayton, near Manchester, Chemical
Manufacturer, do hereby declare the nature of this invention to be as follows:-
This invention consists in improvements in the form and construction of the glass
and other vessels, commonly called retorts, and in the furnaces and other apparatus
used for the concentration of sulphuric and other acids.
The retorts are usually made with dome-shaped tops formed in one piece with
the lower part, with an outlet of small diameter, at the apex or crown, from which
the gases and vapour, which arise during the concentration escape, by a connecting
tube, to the chimney.
In the ordinary mode of operation the retort is only partially filled with acid,
leaving a considerable portion of its surface to the cooling influence of the
atmosphere, so that there is an unequal temperature between that part of the retort
which is filled with acid and the part, above the surface of the acid, which is filled.
with vapour. This inequality of temperature is increased as the concentration:
progresses, owing to the greater density, and consequent higher temperature of the:
acid, and again during the subsequent cooling down of the retort before the acid
can be removed for sale and distribution in glass vessels (carboys), and is a frequent,
cause of fracture of the retorts.
To prevent fracture of the retorts I make these vessels without the upper dome-
shaped portion, in place of which I use a separate hood or cover, made of any.
suitable material, which is connected by a tube with the draught or chimney and
may be made to take off the vapour and gases more effectually than by the methods
hitherto in use, as a stronger draught may be employed owing to the absence of
the danger to the safety of the retort which is caused by unequal heating and
cooling.
On each separate hood or cover I provide one or more sight-holes fitted with
glass, so that the state of ebullition in the vessel or retort may be watched and
controlled by the workmen or attendants.
When the process of evaporation or concentration is in a series of vessels I
construct each of them with a lip or spout for the overflow of the liquid into a shoot
or gutter, of suitable material, so that the acid will flow thereby and by means of
a funnel or tube supported by the hood covering each vessel, from any one vessel
into the next succeeding one. Or I employ two or more syphons communicating
between any two of the vessels, so that if one or more of the syphons should cease
to act, as is not unusual, the flow of acid may be maintained by the other or others.
In the former case, when the lipped vessels are used, it is necessary that they should
be placed at varying elevations; but in the latter case, when the syphons are
employed, the vessels may be placed at practically the same level.
Again, in the former of these two cases I arrange the position of the lips or
spouts so that shoots or gutters of varying lengths may be used, with the object
of conveying the acid, in case of breakage or accident, past any vessel or vessels.
that may be out of use into a further one of the series.
Another part of my invention is the provision of a gutter, channel or tube in the
brickwork, near each vessel, whereby, in the event of breakage, the contained acid,
which would otherwise leak away and be lost or rendered valueless, may be
conducted into a receptacle provided for its recovery.
The vessels may be placed in iron pans, as is usually done, or they may be directly,
exposed to the flame of the open fire, in which case I close the top of the fire

page_text: chamber or chambers in which the vessels are inclosed by means of small circular
segments, of suitable material, lying on an incline so that their own gravity will
cause them to maintain a slight pressure against the sides of the vessels, whilst not
forcibly limiting their expansion, when required, and so that there is no risk of
breaking the fragile material of which the vessels are made.
The two last-named improvements are adapted for use with either the continuous
or the intermittent method of working.
I prefer to have a separate fire to each vessel or retort, but this may be varied
in accordance with the needs and circumstances of each case.
Dated this 13th day of November 1891.
CHRISTOPHER JAMES SCHOFIELD.
COMPLETE SPECIFICATION.
Improvements in Apparatus for Concentrating Sulphuric and other
Acids.
We, MARY ANN SCHOFIELD of Whalley Villa, Whalley Range, Manchester,
Widow, HARRY NORTON SCHOFIELD of Newbridge Barracks, County Dublin,.
Lieutenant in the Royal Horse Artillery and WALTER WHITEHEAD of 17 Market
Street, Manchester, Surgeon, the executrix and executors of the late Christopher
James Schofield, deceased, do hereby declare the nature of this invention and
in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
This invention consists in improvements in the form and construction of the glass
and other vessels, commonly called "retorts," and in the furnaces and other,
apparatus used for the concentration of sulphuric and other acids."
The retorts are usually made with dome-shaped tops formed in one.
piece with
the lower part, with an outlet of small diameter at the apex or. crown, from which
the gases and vapour which arise during the concentration escape, by a connecting
tube to the chimmey.
In the ordinary mode of operation the retort is only partially filled with acid,
leaving a considerable portion of its surface to the cooling influence of the
atmosphere, so that there is an unequal temperature between that part of the retort
which is filled with acid and the part, above the surface of the acid, which is filled.
with vapour. This inequality of temperature is increased as the concentration,
progresses, owing to the greater density, and consequent higher temperature of the
acid, and again during the subsequent cooling down of the retort before the acid
can be removed for sale and distribution in glass vessels (carboys), and is a
frequent cause of fracture of the retorts.
To prevent fracture of the retorts I make these vessels without the upper dome-
shaped portion, in place of which I use a separate hood or cover, made of any
suitable material, which is connected by a tube with the draught or chimney
and may be made to take off the vapour and gases more effectually than by the
methods hitherto in use, as a stronger draught may be employed owing to the
absence of the danger to the safety of the retort which is caused by unequal heating,
and cooling.
"On each separate hood or cover I provide one or more sight holes fitted with
glass, so that the state of ebullition in the vessel or retort may be watched and
controlled by the workmen or attendants.
When the process of evaporation or concentration is in a series of of vessels I'
construct each of them with a lip or spout for the overflow of the liquid into.
a shoot or gutter of suitable material so that the acid will flow thereby and by
means of a funnel or tube supported by the hood covering each vessel from any
one vessel into the next succeeding one. Or I employ two or more syphons
communicating between any two of the vessels, so that if one or more of the syphons

page_text: should cease to act,. as is not unusual the flow of acid may be maintained by the
other or others. In the former case, when the lipped vessels are used, it is:
necessary that they should be placed at varying elevations; but in the latter,
when the syphons are employed, the vessels may be placed at practically the same!
level.
Again, in the former of these two cases I arrange the position of the lips ora
spouts so that shoots or gutters of varying lengths may be used, with the object
of conveying the acid in case of breakage or accident past any vessel or vessels
that may be out of use into a further one of the series.
Another part of my invention is the provision of a gutter, channel. or. tube
in the brickwork near each vessel, whereby, in the event of breakage, the
contained acid, which would otherwise leak away and be lost or rendered valueless:
may be conducted into a receptacle provided for its recovery.
The vessels may be placed in iron pans, as is usually done, or they may be
directly exposed to the flame of the open fire in which case I close the top of
fire chamber or chambers in which the vessels are inclosed by means of small
circular segments, of suitable material, lying on an incline so that their own
gravity will cause them to maintain a slight pressure against the sides of the
vessels, whilst not forcibly limiting their expansion, when required, and so
that there is no risk of breaking the fragile material of which the vessels are
made.
.
The two last named improvements are adapted for use with either the continuous
or the intermittent method of working.
I prefer to have a separate fire to each vessel or retort, but this may be varied
in accordance with the needs and circumstances of each case.
The annexed drawing shews our invention, being marked with letters of
reference indicating like parts in the various figures.
Figure 1 shews an elevation of a series of five retorts or vessels all marked A,
each retort being provided with a lip for the overflow of the acid into the
gutter.
The covers B are each provided with a tube C communicating with the draught
by which the vapour from the acid is to be conveyed away.
The funnels, the tubes of which are shewn by dotted lines, by which the acid
is supplied to the retorts are marked D; the sight holes are marked E.
The gutters which convey the acid are marked F1, F2 and F3. Those marked F¹
shew an arrangement by which the acid is conveyed from one retort to the next
lower one in the series, that marked F2 an arrangement by which the acid is
conveyed from one retort past one or more lower retorts to a further one; F3 shews
a gutter by which the concentrated acid is discharged.
Figure 2 shews a section of a similar series of retorts fitted with syphons
which may be arranged to convey the acid from one retort to any following one
in the series, the horizontal part of the syphon being made of suitable length.
Figure 3 shews a section through the setting of a retort in which the flame
from the fire comes in direct contact with the retort. The fire grate is marked L
and the flue is marked M. In the event of the fracture of a retort containing
acid, the acid would fall into the space marked H, H, and would flow away
thence by the pipe marked J, and from that into another pipe marked K,
discharging at one or both ends into vessels designed to save the acid from being
wasted or spoiled.
The circular segments by which the products of combustion are to be prevented
from passing between the retort and the surrounding brickwork are marked N. N.
These are also shewn in Figure 4.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is
1. The construction of retorts for concentrating acids with
onen tone and a

page_text: separate hood or cover to each, the hood having a tube by which the vapour from
the acid is conveyed away.
2. The construction of the above named covers or hoods with a sight hole or
holes; each hole being fitted with a glass cover.
3. The use of a shoot or gutter to convey the acid from any retort or vessel to
a funnel or tube in the above named separate hood or cover of any other retort
situated lower down in the series.
to
4. The use of two or more syphons to convey the acid from any retort or vessel
any
other situated lower down in the series.
5. The construction of the brickwork setting or furnaces of the retorts or
vessels with gutters, channels or tubes to convey away the acid in the event of the
breakage of a vessel or retort.
6. The construction of sliding pieces surrounding the retorts or vessels, when
these are exposed to the action of the flame from the fire, to prevent the escape
of the products of combustion between the sides of the retorts or vessels and the
surrounding setting furnace or brickwork.
* Dated this Eleventh day of August 1892.
WALTER WHITEHEAD.