Improvements in the Manufacture of Bleaching Powder and in Apparatus for Effecting the same.
Year: 1886

page_text: Date of Application, 28th May, 1886.
Complete Left, 5th Jan., 1887.
Complete Accepted, 8th Feb., 1887.
Improvements in the Manufacture of Bleaching Powder and in
Apparatus for Effecting the same.
We, JOHN BROCK of Widnes in the County of Lancaster, Alkali Manufacturer, and
THOMAS MINTON of Widnes in the County of Lancaster, Alkali Works Manager do
hereby declare the nature of this invention to be as follows:-
Our process has specially for its object the absorption and conversion into bleaching
powder of certain residual chlorine which occurs in the existing process for
manufacturing bleaching powder, otherwise known as chloride of lime, or hypo-chlorite
of calcium.
In this well known process slaked lime is spread in a layer on the floor of chambers,
or boxes, constructed of lead, bricks, slates, flags, or other materials, and there treated
by simple contact "in situ" with chlorine gas until it has absorbed that quantity of
such chlorine which it is desired that it shall contain.
When this point has been reached, the atmosphere of the chamber in which the
process has been conducted still largely consists of chlorine, which the almost saturated
lime does not absorb, and until recently this residual chlorine found its way into the
air either by way of the chamber doors, or the works chimney to the annoyance of
the neighbourhood, and the loss of the manufacturer. Lately this evil has been dealt
with either by drawing this residual chlorine into a chamber containing fresh lime,
or through a tower down which milk of lime was flowing. The first of these
alternatives is cumbrous, and inefficient and the latter does not yield the chlorine as
bleaching powder, but as a liquid.
By our process as set forth below, we obtain this residual chlorine as bleaching
powder, and free the atmosphere of the chamber, box, etcetera, from chlorine, without
using chimney draughts, or necessarily opening the doors of the chamber until its
atmosphere is harmless.
In our process we treat the chlorine gas with lime, in the form of a fine powder
suspended in the atmosphere of the chamber containing chlorine, or in other words,

page_text: we cause the whole atmosphere of such bleaching powder chamber, box, etcetera,
to become charged with a dust of lime, and we find that if we so treat the atmos-
phere of the chamber, box, etcetera, containing chlorine, the chlorine present
is absorbed by the lime dust, and that the said dust is converted into bleaching powder,
provided that in quantity the dust and the chlorine have been properly proportioned
to each other, and that the said dust subsides to the floor of the chamber box etcetera
in great part.
Applying this process to the object of absorbing the residual chlorine in a finished
bleached chamber, or box, we cause to become suspended in the atmosphere of such
chamber or box such an amount of lime dust as is necessary to effect the complete,
or practically complete absorption of the chlorine present. We then allow this dust
_to subside on to the mass of the finished bleach on the floor of the chamber or box.
This subsided lime dust, now bleaching powder is packed along with the main part of
the bleach made by the ordinary process, adding but fractionally to its weight, and
making no sensible difference in the strength. The atmosphere of the chamber or
box has been rendered perfectly harmless, having been practically freed from unabsorbed
chlorine. The amount of lime dust to be added is determined very easily by testing
the chamber or box etcetera for chlorine in its atmosphere, and even with practice by
inspection only. The cubic contents of chamber or box being known, and a test
obtained of the amount of chlorine per unit of contents, the total chlorine present is
obtained by calculation, and the lime to be added deduced from this. The amount
used is in that proportion to the chlorine present that is used in making the main part
of the bleach, but with some excess which may be varied as greater or less rapidity of
absorption is desired.
We have devised apparatus for charging the atmosphere of the bleach chamber or
box etc. with lime dust, and generally for carrying out our process. This apparatus
consists of:
1st. A hopper to contain the lime to be used, with a valve for the purpose of
regulating its rate of 'flow.
2nd. Of a fan to throw the lime dust into the atmosphere of the chamber.
3rd. Of suitable gearing driven by any convenient power for causing the fan to
revolve with the required speed.
The whole of the gearing is enclosed in a cylindrical or other suitably shaped box,
except that part in the neighbourhood of the fan which falls inside the chamber below
the level of the roof of the chamber. In the neighbourhood of the fan the machine
is left open to enable the dust to be thrown into the atmosphere of the chamber. The
necessary support and strength required by the construction of the machine is obtained
at this open part by means of iron tubes, and these tubes have openings about level
with the roof of the chamber, but inside, when the machine is in position. These
tubes also conduce to the proper mixture of the lime dust and the gases of the chamber,
since the rotation of the fan causes the atmosphere of the chamber to flow up these tubes,
and issue at these holes meeting a descending stream of lime dust.
The manner of using the apparatus is as follows. There are luted holes in the top
of the bleach chambers or boxes, or if such exist not, they are to be made. We find
it preferable to have three of these in a 100 feet chamber at regular intervals. The
machine which has a luting flange is fitted to one of these luted holes, and as they are
made to suit one another, it remains in position without escape of chlorine..
The lime dust is filled into the hopper and allowed to slowly escape through the
valve thus falling on to the wings of the fan which being simultaneously kept revolving
at a rapid rate, throws it violently out into the atmosphere of the chamber in which it
becomes suspended, and acts as mentioned in the earlier part of the specification.
Admixture is promoted also by a current of gas which flows up the tubes and meets
the descending lime dust. One third of the total lime is usually introduced at each of
the three lute holes, but this is a matter of detail, and may be varied according to
circumstances.
For this process we claim the following advantages:
1st. That it practically completely stops nuisance and loss from the heretofore

page_text: escapes of chlorine into the air on the opening of finished or partially finished
bleach chambers or boxes.
2nd. That it accomplishes this end without removing the gas from the chamber or
box etc. in which it is, as has to be done when the gaseous contents of the chamber
or box etc. are either drawn by means of chimney or other draught into a freshly
lined chamber or box etc., or through wash towers, in either of which cases there is
constant liability to escape, the draught being constant whether the absorption of the
chlorine is perfect or not..
3rd. The chlorine is recovered as bleach of such strength as to enable it to be mixed
with the great bulk of the manufactured article without deteriorating the latter as a
commercial product.
4th. That the value of the extra bleach thus obtained more than pays for any labour
expended in obtaining it.
With a view to promote subsidence of particles, we sometimes apply electrification
to the lime or bleach dust.
CARPMAEL & Co.,
Agents for the Applicants.

page_text: Improvements in the Manufacture of Bleaching Powder and in
Apparatus for Effecting the same.
We, JOHN BROCK of Widnes in the County of Lancaster, Alkali Manufacturer,
and THOMAS MINTON of Widnes in the County of Lancaster, Alkali Works Manager
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:
Our process has specially for its object the absorption and conversion into bleaching
powder of certain residual chlorine which occurs in the existing process for
manufacturing bleaching powder, otherwise known as chloride of lime, or hypo-
chlorite of calcium.
In this well known process slaked lime is spread in a layer on the floor of chambers,
or boxes, constructed of lead, bricks, slates, flags, or other materials, and there treated
by simple contact "in situ " with chlorine gas until it has absorbed that quantity of
such chlorine which it is desired that it shall contain.
When this point has been reached, the atmosphere of the chamber in which the
process has been conducted still largely consists of chlorine, which the almost saturated
lime does not absorb, and until recently this residual chlorine found its way into the
air either by way of the chamber doors, or the works' chimney to the annoyance of
the neighbourhood, and the loss of the manufacturer. Lately this evil has been dealt
with either by drawing this residual chlorine into a chamber containing fresh lime, or
through a tower down which milk of lime was flowing. The first of these alternatives
is cumibrous, and inefficient and the latter does not yield the chlorine as bleaching
powder, but as a liquid.
By our process as set forth below, we obtain this residual chlorine as bleaching
powder, and free the atmosphere of the chamber, box, etcetera from chlorine, without
using chimney draughts, or necessarily opening the doors of the chamber until its
atmosphere is harmless.
In our process we treat the chlorine gas with lime in the form of a fine powder
suspended in the atmosphere of the chamber containing chlorine, or in other words,
we cause the whole atmosphere of such bleaching powder chamber, box, etcetera, to
become charged with a dust of lime, and we find that if we so treat the atmosphere
of the chamber, box, etcetera, containing chlorine, the chlorine present is absorbed by
the lime dust, and that the said dust is converted into bleaching powder, provided that
in quantity the dust and the chlorine have been properly proportioned to each other,
and that the said dust subsides to the floor of the chamber box etcetera in great
part.
Applying this process to the object of absorbing the residual chlorine in a finished
bleach chamber, or box, we cause to become suspended in the atmosphere of
such chamber or box-such an amount of lime dust as is necessary to effect the
complete, or practically complete absorption of the chlorine present. We then allow
this dust to subside on to the mass of the finished bleach on the floor of the chamber
or box. This subsided lime dust, now bleaching powder is packed along with the main

page_text: part of the bleach made by the ordinary process, adding but fractionally to its weight,
and making no sensible difference in the strength. The atmosphere of the chamber
or box has been rendered perfectly harmless, having been practically freed from
unabsorbed chlorine. The amount of lime dust to be added is determined very easily
by testing the chamber or box etcetera for chlorine in its atmosphere, and even with
practice by inspection only. The cubic contents of the chamber or box being known,
and a test obtained of the amount of chlorine per unit of contents, the total chlorine
present is obtained by calculation, and the lime to he added deduced from this.
The amount used is in that proportion to the chlorine present that is used in making
the main part of the bleach, but with some excess which may be varied as greater or
less rapidity of absorption is desired.
We have devised apparatus for charging the atmosphere of the bleach chamber or
box etc. with limé dust, and generally for carrying out our process. This apparatus.
consists of:
1st. A hopper to contain the lime to be used, with a valve for the purpose of
regulating its rate of flow.
2nd. Of a fan to throw the lime dust into the atmosphere of the chamber.
3rd. Of suitable gearing driven by any convenient power for causing the fan to
revolve with the required speed..
The whole of the gearing is enclosed in a cylindrical or other suitably shaped box,
except that part in the neighbourhood of the fan which falls inside the chamber below
the level of the roof of the chamber. In the neighbourhood of the fan the machine
is left open to enable the dust to be thrown into the atmosphere of the chamber. The
necessary support and strength required by the construction of the machine is obtained
at this open part by means of iron tubes, and these tubes have openings about level
with the roof of the chamber, but inside, when the machine is in position. These tubes
also conduce to the proper mixture of the lime dust and the gases of the chamber,
since the rotation of the fan causes the atmosphere of the chamber to flow up these
tubes, and issue at these holes meeting a descending stream of lime dust.
The manner of using the apparatus is as follows. There are luted holes in the top
of the bleach chambers or boxes, or if such exist not, they are to be made. We find
it preferable to have three of these in a chamber 100 feet long at regular intervals.
The machine which has a luting flange is fitted to one of these luted holes, and as they
are made to suit one another, it remains in position without escape of chlorine.
The lime dust is filled into the hopper and allowed to slowly escape through the
valve, thus falling on to the wings of the fan which being simultaneously kept
revolving at a rapid rate, throws it violently out into the atmosphere of the chamber
in which it becomes suspended, and acts as mentioned in the earlier part of the
Specification.
Admixture is promoted also by a current of gas which flows up the tubes and meets
the descending lime dust. One third of the total lime is usually introduced at each of
the three lute holes, but this is a matter of detail, and may be varied according to
circumstances.
For this process we claim the following advantages.
1st. That it practically completely stops nuisance and loss from the heretofore escape
of chlorine into the air on the opening of finished or partially finished bleach chambers
or boxes.
2nd. That it accomplishes this end without removing the gas from the chamber or
box etc. in which it is, as has to be done when the gaseous contents of the chamber or
box etc. are either drawn by means of chimney or other draught into a freshly lined
chamber or box etc. or through wash towers, in either of which cases there is constant
liability to escape, the draught being constant whether the absorption of the chlorine
is perfect or not.
3rd. The chlorine is recovered as bleach of such strength as to enable it to be mixed
with the great bulk of the manufactured article without deteriorating the latter as a
commercial product.

page_text: 4th. That the value of the extra bleach thus obtained more than pays for any labour
expended in obtaining it.
With a view to promote subsidence of particles, we sometimes apply electrification
to the lime or bleach dust.
In order that our said invention may be fully understood and readily carried into
effect we will proceed to describe the drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is an elevation of apparatus by means of which our invention may be
carried into effect. Figure 2 is a vertical section Figure 3 is a plan and Figure 4
is an horizontal section on the line N. N. in Figure 2.
A represents the top or roof of the bleach chamber. B is a box or casing inserted
into an aperture in the roof A. A gas tight joint is formed at B₁. C is a hopper at
the top of the casing, it is charged with quicklime in fine powder. D is a valve at the
bottom of the hopper, it is opened by means of a lever represented in the drawing to
permit the lime gradually to descend whilst the apparatus is at work. E is a toothed
wheel carried by a stud axis on the side of the casing; there is a crank handle upon
the wheel by means of which it is turned when the apparatus is in use. F is a pinion
on an horizontal axis which also carries a bevilled wheel G. The wheel G gears with
a bevilled pinion on a vertical axis H which is armed with blades I. I. forming a fan
or distributer. Bearings for the axes are provided upon the casing. The lower
bearing is supported by the tubes K. K. which are ranged around the fan or distri-
butor. The tubes are open at their lower ends and there are apertures in them
at K' K¹ these apertures are directed inwards and when the fan or distributor is in
motion an upward current is maintained through the tubes and out through these
apertures.
This current meets the lime descending from the hopper, passes with it to the fan or
distributer and then issues all around between the tubes K. K. In this way the finely
divided lime is caused to pervade and permeate every part of the bleach chamber.
It will be observed in the operation of introducing and distributing the lime dust
no air is introduced into the chamber from the outside; that put in motion by the fan
or distributer being the air or gas already in the bleach chamber; this is important as
the admission of air at this stage would be deleterious.
Other apparatus may be employed for projecting the powdered lime into the bleach
chamber but that described will be found very convenient.
Having now particularly described and ascertained the nature of our said invention
and in what manner the same is to be performed we declare that what we claim is
:-
1. Our improvement in the process for the manufacture of bleaching powder con-
sisting in projecting finely pulverized lime into the absorption chamber at the end of
the operation and thereby fixing the residual chlorine by which waste and nuisance is
avoided.
2. Apparatus to be used in the manufacture of bleaching powder consisting in a
casing or box inserted into a hole in the top of the bleach chamber and provided with
a hopper and a rotating fan or distributer; the whole so arranged that the lime
descending from the hopper is dispersed by the fan or distributer and caused to
permeate the bleach chamber substantially as described.
CARPMAEL & Co.,
Agents for the Applicants.