Improvements in the Methods of and Apparatus for Water Purification."
Year: 1896

page_text: Date of Application, 19th Dec., 1896-Accepted, 18th Dec., 1857
COMPLETE SPECIFICATION.
"Improvements in the Methods of and Apparatus for Water
Purification."
I, ISAAC SIIMWELL MCDOUGALL, of High Bank, Didsbury, in the County of
Lancaster, Manufacturer, 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:-
My Invention relates to the purification of water by precipitation, and my
object is to provide precipitants of such nature as to render oily or greasy matters
insoluble for one class of water; to provide precipitants for precipitating lime in
solution in another class of water, and to carry out the reactions in a suitable
apparatus so arranged as to enable the water to be kept at or near the boiling
point.
Part of my invention consists in the application of calcium chloride or a
mixture of calcium chloride and caustic lime for the purpose of
precipitating oily matters in water. Another part consists in the
application of a mixture of caustic soda and carbonate of soda for the precipitation
of lime or magnesia; and a third part of my invention consists in heating the
water to or near the boiling point while these reactions proceed in a special forin
of apparatus.
In carrying my invention into effect as applied to impure or oily water, such
water for example as condensed water from a marine engine or other condensing
engine, I pass the said water into a suitable tank, and raise it to the boiling point.
I then add to the water a solution coutaining calcium chloride or a mixture of
calcium chloride and caustic lime. The solution has the effect of causing a
separation of fatty matter at the boiling point in a condition easily removed by
filtration.
In carrying my invention into effect for a water either with or without oil, but
containing lime or other metallic salts in solution, either as carbonate or sulphate,
I also raise the water to the boiling point in a suitable tank, and add to it a
mixture of caustic soda and carbonate of soda. A precipitate is formed, which is
filtered off.
In both cases I so proportion the addition of my precipitating solutions that he
water 18 left slightly alkaline, or is at least neutral after the complete
precipitation.
My invention can be carried into effect with many different modifications of
apparatus, but I prefer an apparatus which I will now describe.
Referring to the accompanying sheet of drawings.
Figure 1 shows in longitudinal section one modification, and-
Figure 2 another modification.
The accompanying drawing Figure 1 shows a longitudinal section through such
an apparatus which consists of a tank A having a steam coil D), water supply pipe
E, and water discharge pipe B. My precipitant solution is contained in a small
tank C, and the large tank A has a partition F and a mud cock G.
The water to be purified is supplied by the pipe E. It is heated up to the

page_text: boiling point by the coil D. The partition F so acts as to practically divide the
large tank A into a small tank containing the coil D, which highly heats the
water in that part of the tank, and so produces the deposition of the precipitant
above the mud-cock where shown. The purified water then passes the partition
into the larger part of the tank, and is withdrawn for use by the pipe B."
The coil may be open at the end within the tank to enable steam to be blown
directly into the water in the tank.
As an alternative method, instead of employing the tank C sufficient of the
calcium chloride or mixture of calcium chloride and caustic lime may be passed
directly into the steam boiler, so as to saturate the water in the boiler to say about 2
degrees Twaddel. This saturated water is then passed from the boiler to the tank
A (see Figure 2) by means of a pipe and tap adjustment, in sufficient quantity
to heat the water, and give sufficient chemical to render fatty acids insoluble and
ready for filtration. By this method the process becomes continuous as long as
the herein before mentioned chemicals in the boiler are kept at the required
strength, and whenever it is found deficient a little more only requires to be
added. In practice it is found that the chemicals used act chiefly as a means of
separating the fatty matter from the water, and in so doing are not exhausted,
but pass through the filter in solution to the boiler ready for use again. This
application is inore especially intended for the purification of waters containing
fatty matter.
In Figure 2 a modificaion is shown carrying the system into effect. The tank
C is used to add the chemicals to the water in A to keep up the strength of the
solution in the boiler. The pipe or coil D is open at the tank end, and com-
municates with the boiler by a cock H too small to incur any danger of blowing
too much water out of the boiler.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is.
1. A separator or precipitant for oily or greasy water consisting of calcium
chloride or a mixture of calcium chloride and caustic lime substantially as
hereinbefore described.
2. A separator or precipitant for waters containing dissolved lime or other
metallic salts either as carbonate or sulphate, consisting of a mixture of caustic
soda and carbonate of soda, the said precipitant being applied to the water to be
purified while the water is at or near the boiling point substantially as herein-
before described.
3. The process of separating or precipitating the oily or greasy matter in
water by the addition of calcium chloride or a mixture of calcium chloride and
caustic lime at or near the boiling point of the water substantially as herein before
described.
4. The apparatus hereinbefore described and illustrated in the accompanying
drawings for carrying out the separating or precipitation of impurities in water
at or near the boiling temperature substantially as hereinbefore described.
Dated this 19th day of December, 1896.
MARKS & CLERK
18 Southampton Buildings, London. W.C. &
13 Temple Street, Birmingham. Agents for the Applicant.