Improvements in the Manufacture of Disinfecting, Deodorizing, and Bleaching Agents, and in Apparatus therefor.
Year: 1896

page_text: Date of Application, 4th July, 1896.
Complete Specification Left, 3rd Dec., 1896-Accepted, 23rd Jan., 1897
Improvements in the Manufacture of Disinfecting, Deodorizing, and
Bleaching Agents, and in Apparatus therefor.
I, MIDDLETON CRAWFORD, of 37 New Oxford Street, in the County of
Middlesex, Electrical Engineer, do hereby declare the nature of this invention to
be as follows:-
This invention relates to the manufacture of disinfecting deodorizing and
bleaching agents from sea-water or other saline solution by subjecting it to the
action of an electric current. The effect of this treatment of the sea-water is to
more or less charge it with hypochlorites and other compounds of a similar
nature.
Heretofore it has not been possible to satisfactorily and economically manufacture
disinfecting and similar agents from sea-water in this manner. One of the
difficulties experienced in the above process relates to charging the solution
with the hypochlorites. A further difficulty relates to keeping the said solution
stable; that is to say to keep it in its charged condition until brought into contact
with the infected or other substances required to be acted upon.
I have discovered that the chief cause of failure has been due to the considerable
rise in temperature which the sea-water or other saline solution experienced during
the electrolytic action; and one of the objects of my invention is to so manufacture
the disinfecting agents that this considerable rise in temperature will be avoided,
and, as a consequence, to enable the manufacture to be carried on more economically
than heretofore, to enable the solution to be charged with a much greater quantity
of the hypochlorites and to cause such hypochlorites to remain more permanently
in the solution.
In carrying out my invention I may employ any suitable form of electrolyzing
vat which is preferably made of wood. In this vat I arrange electrodes of any
appropriate construction.
I prefer to separate the anodes and cathodes of the electrodes by means of
porous partitions which may be composed of earthenware or other suitable
substance. The intermingling of the gases generated at the opposite poles of the
electrodes and of the solution or electrolyte in the vicinity of the said opposite
poles is thus prevented and the neutralising effect of such intermingling is
therefore avoided.
The gases generated during the exercise of the electrical energy at the anode or
positive pole are known to be free oxygen and free chlorine and at the cathode or
negative pole, free hydrogen. The volume of hydrogen gas resulting from the
decomposition of the water (H2O) is double the volume of oxygen, and when the
oxygen and hydrogen are not kept apart the hydrogen rushes to the surface,
produces violent agitation of the electrolyte, and carries with it the oxygen,
thereby causing the electrolyte contiguous to the anode to intermingle with and
neutralize the electrolyte contiguous to the cathode thus producing a waste of
electrical energy and of the desired products. I find that the more freely the
oxygen is generated and the more effectually it is prevented from mingling with
the bydrogen the more economically will the desired quality of electrolyte be
produced and the more permanent will be the suspension of the gases therein.

page_text: By this means the entire volume of available oxygen operates on the salts in the
solutions and acts to increase the electrical conductivity of the solution, to
facilitate the development of the hypochlorites, hypobromites, hypoiodites and
such like compounds, and to aid in their concentration.
vat.
For the purpose of keeping the solution in the electrolyzing vat cool I may
employ any appropriate means such as cold compressed air admitted into the said
Or the vat may be surrounded with ice, or may have a jacket through which
very cold water can be caused to flow. Or cylinders or vessels containing ice or a
freezing liquid may be situated within the solution in the vat. Or if I am treating
liquid effluent the latter may be conducted in a cool condition, into and through
the said electrolyzing vat. I wish it to be understood that any convenient
refrigerating means may be employed for my purpose.
Practical experience demonstrates that the higher the temperature of the
electrolyte becomes after it reaches 60 F., the greater is the waste of electrical
energy. It will also be evident that the continuous inflow of electrical energy
tends to cause a marked and continuous increase in the temperature of the
electrolyte, and that unless some method be employed to prevent this, it is quite
impracticable to manufacture hypochlorites from saline solutions on an economical
scale, or to cause the generated gases to remain in suspension in the solution, or to
concentrate the same so that a large number of grains of hypochlorite per imperial
gallon can be developed.
I have found that the saline solution, while being operated upon by the electric
current, should be maintained at a moderately low temperature, say 50 F. or less.
The nearer the temperature of the electrolyte approximate 100 F. the greater
the waste of electrical energy and the destruction of the electrolyte. After it
reaches that point it is practically impossible to retain the hypochlorites at all, as
the heat drives off the chlorine. The importance of retaining the chlorine (or
hypochlorite) in the electrolyte for as long a period as possible cannot be over
estimated, particularly when the disinfectant is to be employed in the treatment of
sewage. The effect of the hypochlorites upon organic matters is to oxidise the
same, and convert the nitrites, which are noxious and valueless substances for
fertilising purposes, into nitrates which are highly valuable manurial substances.
Should the chlorine (hypochlorite) be driven off from the electrolyte or be too
volatile, a great loss in the commercial value of the product results when
treating sewage or sludge in bulk. Hence the importance of not only being able
to manufacture the hypochlorites economically but also under such conditions as
to ensure its least volatility, both of which ends are obtainable by cooling the
electrolyte.
I also find it practicable and economical to manufacture a highly concentrated
hypochlorite solution as described, and apply small quantities to bleaching
Bolutions, sewage or sewage effluents, or other uses as described.
The electrodes that I prefer to employ are preferably so constructed that the
anode possesses a large area; that the conductors or the portions of the electrodes
that convey the electric current directly to the said electrodes are protected
from the corrosive action of the electrolyte so that I can employ an inexpensive
metal for such purpose; and that the electrodes can be immersed to any desired
extent into the electrolyte without detrimentally affecting the said inexpensive
metal.
For these purposes the said electrodes may be carried in holders or frames
of copper coated with india-rubber which is vulcanised after its application to
the said bolders or frames. The electrodes may be supported from a convenient
overhead beam by means of an adjustable rod or cord so that the extent to
which the electrodes are immersed into the electrolyte can be readily controlled.
By my invention 1 obtain a highly economical method of manufacturing bypo-
chlorites on a commercial scale whereby it is possible to manufacture a solution
of hypochlorites possessing a known and regular number of grains of available
hypochlorites per imperial gallon; and whereby the manufacture may be carried

page_text: on in such a way that the hypochlorites will remain in suspension in the solution
for an indefinite period and in a condition to exercise their beneficial potency in
the presence of organic matter. Moreover, a solution can be manufactured which
can be conveniently and commercially transported and which will retain its powers
wherever it may be used and after any reasonable lapse of time; furthermore the
hypochlorites may be manufactured in such a form that the manurial values of
crude sewage treated therewith will be greatly improved and thus lessen the
expenses of sewage operations.
Dated this 2nd day T... 100
Improvements in the Manufacture of Disinfecting, Deodorizing, and
Bleaching Agents, and in Apparatus therefor.
I, MIDDLETON CRAWFORD, of 37 New Oxford Street, in the County of
Middlesex, Electrical Engineer, 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 relates to the manufacture of disinfecting deodorizing and
bleaching agents from sea-water or other saline solution by subjecting it to the
action of an electric current. The effect of this treatment of the sea-water or
ealine solution is to more or less charge it with hypochlorites and other compounds
of a similar nature.
Heretofore it has not been practicable to satisfactorily and economically
manufacture disinfecting and similar agents from sea-water or saline solutions in
this manner, one reason being the difficulty experienced in satisfactorily charging
the solution with the hypochlorites. A further difficulty relates to keeping
developed compounds in the said solution stable, that is to say to keep the solution
in its charged condition until brought into contact with the infected or other
substances required to be acted upon.
I have discovered that the chief cause of failure has been due to the considerable
rise in temperature which the sea-water or other saline solution experiences during
the electrolytic action; and one of the objects of my invention is to so manufacture
the disinfecting agents that this considerable rise in temperature will be avoided,
so that the manufacture can be effected more economically than heretofore; another
object is to enable the solution to be charged with a much greater quantity of the
hypochlorites and other compounds and to cause them to remain more permanently
in the solution than heretofore.
In carrying out my invention I may employ any suitable form of electrolyzing
vat which is preferably made of wood or slate and in this vat I arrange electrodes
of any appropriate construction.
I prefer to separate the abodes and cathodes of the electrodes by means of
porous partitions which may be composed of earthenware or other suitable porous
substance. The intermingling of the gases generated at the opposite poles of the
electrodes and the intermingling of the electrolyte in the vicinity of the said
opposite poles is thus prevented and the neutralising effect of such intermingling is
therefore avoided.
The gases generated during the exercise of the electrical energy at the anodes
are known to be free oxygen and free chlorine and at the cathodes free hydrogen

page_text: The volume of hydrogen gas resulting from the decomposition of water (H2O) is
double the volume of oxygen, and when the oxygen and hydrogen are not kept
apart the hydrogen rushes to the surface of the liquid, produces violent agitation of
the electrolyte, and carries with it the oxygen, thereby causing the electrolyte
contiguous to the anodes to intermingle with and neutralize the electrolyte contiguous
to the cathodes; a considerable waste of electrical energy and of the desired
products therefore ensues. I find that the more freely the oxygen is generated
and the more effectually it is prevented from mingling with the hydrogen, the more
economical will be the production of the desired quality of disinfectant and the
more permanent will be the suspension of the disinfecting agents therein. By my
invention the entire volume of available oxygen operates on the salts in the
electrolyte and acts to increase the electrical conductivity of the electrolyte so that
the development of the hypochlorites, hypobromites, hypoiodites and such like
compounds is facilitated and their concentration aided.
I also find that there is a loss of electrical energy in ordinary electrolyzing processes,
owing to the absence of proper agitation of the electrolyte and the consequent
wide differences of temperature in different parts of the electrolyte. In order to
obviate this, as well as to secure the requisite cooling of the electrolyte, I introduce
a jet of compressed air at a suitable point in the electrolyzing vat, the said jet
being preferably directed towards the field of electrical energy. By these means
a current or currents in the electrolyte is established with the result that every
portion of the electrolyte is brought within the field of electrical energy and a
comparatively uniform temperature is maintained throughout all parts of the
electrolyte.
If desired I may employ other means than the cold compressed air for keeping
the electrolyte cool. For instance the vat may be surrounded with ice, or may
have a jacket, through which very cold water can be caused to flow. Or cylinders
or vessels containing ice or a freezing liquid may be situated within the electrolyte
in the vat. Or if I am treating liquid effluent the latter may be conducted, in a
cool condition, into and through the said electrolyzing vat. I wish it to be
understood that any convenient refrigerating means inay be employed for my
purpose.
The electrodes that I employ are preferably so constructed that the anodes
possess a large area. The conductors or the portions of the electrodes that convey
the electric current directly to them may be protected from the corrosive action
of the electrolyte so that I can employ an inexpensive metal for such purpose.
The electrodes are also advantageously so arranged that they can be immersed to
any desired extent in the electrolyte without detrimentally affecting the said
inexpensive metal.
For these purposes the said electrodes may be carried in holders or frames which
may be coated with indiarubber vulcanised after its application to the said holders
or frames. The electrodes may be supported from a convenient overhead beam by
means of an adjustable rod or cord so that by operating said rod or cord the
extent to which the electrodes are immersed into the electrolyte can be readily
controlled.
In order that my said invention may be more fully understood and readily
carried into effect I will proceed to describe the drawings hereunto annexed, in
which
Figure 1 is a vertical section of the electrolyzing vat shewing the, electrodes and
the pipe for conveying cool air under pressure to the vat.
Figure 2 is a plan of Figure 1.
:
Figure 3 is an elevation and Figure 4 a plan of one of the cathodes and a porous
cell in which it is contained.
Figure 5 is an elevation and Figure 6 a cross section of one of the anodes.
A is the vat containing the saline solution, such as sea-water, to be electrolyzed
and thereby charged with hypochlorites and other compounds of a similar nature.
B is the pipe for conducting the cool compressed air to the vat from a suitable

page_text: compressing apparatus thereby keeping the electrolyte cool and agitating it.
CC are the cathodes and D D the anodes.
The aforesaid cathodes consist of sheets of zinc bent into the forin represented
in Figure 4 so as to present a comparatively large area to the electrolyte without
occupying much space. To each of these cathodes are connected arnice having
bent upper ends which rest upon cross pieces e forming part of a frame E from
which all the electrodes are suspended.
Each of the said cathodes is contained in a porous cell F having lugs fat its
mouth for resting upon the aforesaid cross pieces e and supporting the cells in
position. These porous cells serve as partitions to separate the anodes and cathodes
so that the intermingling of the generated gases and of the electrolyte in the
immediate vicinity of the electrodes is prevented.
The anodes D consist of thin plates of platinum mounted in ebonite or other
suitable frames dd, to which are rigidly secured a pair of vertical ebonite or other
suitable strips d¹. The said strip di cover and insulate a two-part vertical metallic
bar or electric conductor d' which is in contact with the platinum plates of the
anode and which is tightly held by the strips d. The upper parts of the bar d
and strips d'have horizontal arms d³ d by which the anode is suspended from the
cross bars e of the aforesaid frame E. The said arms d³ and the arms c of the
cathodes have depending pieces d* c* respectively, which dip into mercury
troughs el formed in the cross bars e whereby the said electrodes are put into
electric connection with the conductors ay leading from a dynamo electric
machine or other source of electric supply, the said conductors dipping into the
mercury troughs e¹ e².
The frame in which the electrodes are suspended may be supported by any
convenient meaus, such as a rope attached to the eye E' and passing over a pulley
carried by an overhead beam so that such electrodes can be readily immersed. into
or withdrawn from the electrolyte, or their position therein be adjusted as may be
required.
The part of the aforesaid pipe B by which the compressed cool air is conveyed
to the electrolyte is advantageously made curved as shewn in Figure 2 and.is
formed with an outlet at 6 through which the cool air is ejected into the electrolyte
so as to have both a cooling and an agitating effect thereon. Obviously this pipe
may be made of other shape if desired. B is a valve for regulating the passage
of the compressed air through the pipe B. The aforesaid cooling of the electrolyte
is of much importance because practical experience demonstrates that the higher
the temperature of the electrolyte becomes after it reaches about 60° F., the
greater is the waste of electrical energy. It will be evident that the continuous
inflow of electrical energy tends to cause a marked and continuous increase in the
temperature of the electrolyte, and that unless some method be employed to prevent
this, it is quite impracticable to manufacture hypochlorites from saline solutions on
an econonical scale, or to cause the generated gases to remain in suspension in the
solution, or to concentrate the same so that a large number of grains of hypochlorites
per imperial gallon can be developed.
I have found that the saline solution, while being operated upon by the electric
current, should be maintained at a moderately low temperature, say 50° F. or less.
The nearer the temperature of the electrolyte approximates 100° F. the greater is
the waste of electrical energy and the less effective is the disinfecting agent
produced. After the temperature reaches that point it is practically impossible to
retain the hypochlorites at all, as the heat drives off the chlorine. The importance
of retaining the chlorine (or hypochlorite) in the electrolyte for as long a period as
possible cannot be over-estimated, particularly when the disinfectant is to be
employed in the treatment of sewage. The effect of the hypochlorites upon organic
matters is to oxidise the same, and convert the nitrites, which are noxious and
valueless substances for fertilizing purposes, into nitrates which are highly valuable
manurial substances.
Should the chlorine (hypochlorite) be driven off from the electrolyte or be too

page_text: volatile, a great loss in the commercial value of the product results when treating
sewage or sludge in bulk. Hence the importance of not only being able to
manufacture the hypochlorites economically but also under such conditions as to
ensure their least volatility, both of which ends are obtainable by cooling the
electrolyte in the manner stated.
I also find it practicable and economical to manufacture a highly concentrated
hypochlorite solution as described, and to apply small quantities thereof to bleaching
solutions, sewage or sewage effluents, or to other uses as described.
By my invention I obtain a highly economical method of manufacturing hypo-
chlorites on a commercial scale whereby it is possible to manufacture a solution of
hypochlorites possessing a known and regular number of grains of available hypo-
chlorites per imperial gallon; and the manufacture may be carried on in such a way
that the hypochlorites will remain in suspension in the solution for an indefinite
period and in a condition to exercise their beneficial potency in the presence of
organic matter. Moreover, a solution can be manufactured which can be
conveniently and commercially transported and which will retain its powers wherever
it may be used and after any reasonable lapse of time. Furthermore the hypo-
chlorites may be manufactured in such a form that the manurial values of crude
sewage treated therewith will be greatly improved and thus lessen the expenses of
sewage operations.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I would here state that
I am aware that it has before been proposed to cool an electrolyte whilst being
-subjected to the action of an electric current and to such cooling I lay no claim,
but what I do claim is :-
1. A method of economically manufacturing a solution charged with hypo-
chlorites and other compounds of a similar nature, for the purposes specified,
consisting in treating a saline solution electrolytically by electrodes, that are
separated from one another by porous cells or partitions, and simultaneously
agitating and cooling the said solution substantially as described.
2. Apparatus comprising a vat containing the electrolyte, means for keeping the
electrolyte cool and agitating it, and means such as porous cells or partitions for
separating the anodes from the cathodes, all substantially as described and for the
purpose specified.
3. The manufacture of disinfecting deodorizing and bleaching agents by
electrolytically treating a saline solution in the manner and by the means herein-
.before stated.
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.