IMPROVEMENTS IN THE SOFTENING OF WATER
Year: 1878

page_text: LETTERS PATENT to Alfred Ashby, of Grantham, in the County. of Lincoln,
Surgeon, for the Invention of "IMPROVEMENTS IN THE SOFTENING OF
WATER
"
Sealed the 9th May 1879, and dated the 29th November 1878.
PROVISIONAL SPECIFICATION left by the said Alfred Ashby at the Office
of the Commissioners of Patents on the 29th November 1878.
ALFRED ASHBY, of Grantham, in the County of Lincoln, Surgeon.
MENTS IN THE SOFTENING OF WATER."
" IMPROVE-
The process is more particularly useful for manufacturing and industrial purposes,
but may also be employed for removing the whole or a part of the hardness from
water which is used for drinking or domestic purposes. It can also be employed
for removing permanent hardness from water even if it contains very little or no
temporary hardness.
After the temporary hardness, which is due to the presence of bicarbonates of
lime and magnesia and salts of iron has been removed from the water by the
addition of lime or lime water (the well known Clark's process) by boiling or by
any other known method I add for the purpose of removing the permanent hard-
ness which is due to the presence of soluble salts of lime, magnesia, and iron, other
than those which cause the temporary hardness a sufficient quantity of carbonate
or bicarbonate of soda or potash or of any other soluble carbonate or bicarbonate
which will decompose and effect the precipitation in an insoluble form of these sub-
stances which produce the permanent hardness either with or without the aid of
heat, which may be applied either by means of a fire or by passing steam through
coils of pipes placed in the water which is being softened or by blowing steam
directly into the latter.
Or I remove the magnesia, which may wholly or partially cause the permanent
hardness, by the addition of an excess of lime during the removal of the temporary

page_text: hardness whereby the water is rendered alkaline, and the magnesia is precipitated
in an insoluble form, the excess of lime being subsequently removed by the addition
of a sufficient quantity of carbonate or bicarbonate of soda, or potash, or of any
other soluble carbonate or bicarbonate, and when necessary, by the addition of
some free carbonic acid gas after the addition of the soluble carbonate, whereby
any caustic alkali which may have been formed is converted into a carbonate.
In the process I have described the free and half combined carbonic acid gas is
first removed so that the subsequent removal of the permanent hardness is rendered
both practicable and easy.
The process may be used in conjunction with the Clark's process, but I prefer to
use it in conjunction with the Porter-Clark process (described in the Specification
of a Patent No. 1697, in the year 1876) which removes the temporary hardness
from water.
After water has been treated by my process it is devoid of all hardness so that
it is equal to distilled water for washing and many manufacturing purposes.
I prefer to carry out my process by first determining the proper quantities of
soluble carbonates or bicarbonates which are required for exactly removing the
permanent hardness from any water, and in doing so I use as an indicator
mercurous nitrate, mercuric nitrate, calcic chloride, turmeric, litmus, or any other
suitable reagent, either before or after heating a definite quantity of the water to
which has been added a known quantity of a solution of the carbonates or
bicarbonates of a previously ascertained strength.
The proper proportions are then easily regulated by making a saturated solution
of the carbonates or bicarbonates, and adding a measured quantity of it to a known
quantity of water in a tank or any other suitable receptacle, or by using a weighted
quantity of the salts. It is then run from that into the mixed hard water and
lime water in a mixing tank, the proper flow being determined by regulating
valves or floats, and the water is then agitated in the mixing tank by stirring gear
or by any other method.
I prefer to have a separate mixing tank in which the water may be mixed with
the solution of the carbonates or bicarbonates after the lime water has been pre-
viously added in another mixing tank. The second mixing tank should be of
somewhat larger dimensions than the first one in which the lime is added to the
hard water. Heat is applied to the water in the second mixing tank if necessary
in the manner already described, waste or exhaust steam from an engine or any
other apparatus being a very economical way of applying the heat, and the steam
may, with great advantage, be carried through a second coil of pipes placed in the
first or lime water mixing tank so as to utilize as much as possible of the heat, and
then to obtain the condensed steam as distilled water which can then be mixed
with the softened water or used separately from it.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Alfred Ashby in the Great Seal Patent Office on the 28th May
1879.
ALFRED ASHBY, of Grantham, in the County of Lincoln, Surgeon. "IMPROVE
MENTS IN THE SOFTENING OF WATER."
;
The process is more particularly useful for manufacturing and industrial pur-
poses, but may also be employed for removing the whole or a part of the hardness
from water which is used for drinking or domestic purposes.
After the temporary hardness, which is due to the presence of bicarbonates of
lime and magnesia and salts of iron has been removed from the water by the
addition of lime or lime. water (the well known Clark's process) by boiling or by
any other known method I add for the purpose of removing the permanent hard-
ness which is due to the presence of soluble salts of lime, magnesia, and iron, other
than those which cause the temporary hardness, a sufficient quantity of a solution
of carbonate or bicarbonate of soda, or potash, or of any other soluble carbonate or
bicarbonate from a tank or reservoir of any description which will decompose and
effect the precipitation in an insoluble form of the substances which produce the
permanent hardness either with or without the aid of heat, which may be applied
either by means of a fire or by passing steam through coils of pipes placed in the
water which is being softened or by blowing steam directly into the latter. The
waste or exhaust steam from a steam engine may be employed as an economical
source of heat. Or I remove the magnesia, which may wholly or partially cause
the permanent hardness by the addition of an excess of lime during the removal of
the temporary hardness whereby the water is rendered alkaline, and the magnesia
is precipitated in an insoluble form, the excess of lime being subsequently removed
by the addition of a sufficient quantity of carbonate, or bicarbonate of soda, or
potash, or of any other soluble carbonate or bicarbonate, and when necessary by
the addition of some free carbonic acid gas after the addition of the soluble car-
bonate whereby any caustic alkali which may have been, formed is converted into
a carbonate.
I prefer to have a separate mixing tank, in which the solution of carbonate or
bicarbonate may be added after the lime water has been previously added to the
hard water in another mixing tank, and to have the second mixing tank of larger
dimensions than the first. Where there is steam or other power, stirring gear
should be placed in each tank.
In the process I have described the free and half combined carbonic acid gas is
first removed so that the subsequent removal of the permanent hardness is rendered
both practicable and easy.
The process may be used in conjunction with the Clark's process; but I prefer to
use it in conjunction with the Porter-Clark process (described in the Specification
of a Patent No. 1697, in the year 1876) which removes the temporary hardness
from water or any other method of filtering the turbid water.
After water has been treated by my process it is devoid of all hardness so that
it is equal to distilled water for washing and many manufacturing purposes.
When determining the proper proportion of soluble carbonate or bicarbonate to
be used I proceed as follows:-
After a sufficient quantity of lime or lime water has been added to combine with
the free and half combined carbonic acid, or if required sufficient also to remove
magnesia in an insoluble form I take a measured quantity, say a quarter or half
litre, of the water (which will now have assumed a milky appearance owing to the
deposition of insoluble matters) and drop into it from a graduated glass measure
(e.g., a burette divided into cubic centimetres and parts of cubic centimetres) some

page_text: solution of soluble carbonate or bicarbonate of one per cent. strength, or of any other
strength that may be found to be most convenient, and preferably some of the same
solution that is going to be used in the process of softening, and then raise the
water to as nearly as can be the same temperature as that to which it will be.
subjected during the process.
In order to ascertain when just a sufficient quantity of the solution as been
added I make use of turmeric paper or reddened litmus paper so as to avoid having
an alkaline reaction in the water, or I add a little solution of calcic chloride to
some of the water after it has been filtered into a glass vessel when no turbidity
ought to be produced in the water, or I add some of the filtered water to a few
drops of a solution of mercurous nitrate or of mercuric nitrate placed in a white
basin, when no change of colour ought to take place, or I use any other convenient
chemical reaction as an indicator. If a slight degree of alkalinity in the softened
water is of no consequence so much care need not be bestowed on this point.
Should it be desired to remove only a portion of the permanent hardness a
smaller quantity of the solution of carbonate than is indicated above may be added,
and the resulting hardness of the partially softened water may then be ascertained
by the standard solution of soap in ordinary use.
Having now determined the relative proportions of the water which is to be
softened, and of the solution of soluble carbonate or bicarbonate which must be
used in order to effect the desired amount of softening the size of the orifices of
the rectangular valves or openings through which either flows into the second
mixing tank must be adjusted in like proportions. For example, if 1000 measures
(say one litre) of the water required 10 measures (say 10 cubic centimetres) of the
solution of carbonate the two orifices must have the relative areas of 1000 and 10.
I effect this adjustment by having a slide plate fitting into one or both of the
rectangular openings, which is moved by a screw so as to increase or diminish the
size of the openings. A graduated scale is placed either by the side of the sliding
plate or on a circular plate at the end of the screw, which is used for turning it,
or in both positions combined.
In this manner the relative areas of the openings can be readily and accurately
adjusted. I take care that the fluid issuing from each opening has as nearly as
possible the same head of pressure; a float can be arranged so as to cut off the
orifices in equal proportions as the mixing tank becomes filled.
I prefer to use a similar arrangement for accurately adjusting the relative propor-
tions of the original hard water and the lime water when flowing into the first
mixing tank.
Having now set forth the nature and modes of carrying out my Invention I may
observe that water having temporary and permanent hardness may be softened by
the addition of soluble carbonates and applying heat, but this is an uncertain
manner of effecting the desired result, requiring often a large quantity of the
carbonate, and leaving the softened water with a strongly alkaline reaction
which is objectionable for many purposes, as for instance, in the washing of
woollen, linen, and colored articles, and in dyeing, it is also a very wasteful way
of using the carbonates.
Now in my Invention it is not attempted to remove the permanent hardness
until all the free and half combined carbonic acid which was originally present in
the water has been removed, when it becomes an easy matter to add just sufficient
soluble carbonate or bicarbonate to remove the whole or just so much as may be
desired of the permanent hardness, thereby effecting a great saving in the
quantity of the carbonate used, and yielding a water almost entirely free from
any hardness, and having no alkaline reaction, which is of so great importance in
many processes.
What I claim is my process, substantially as described, of softening water,
consisting in the addition in suitably adjusted proportion of carbonate of soda or
other soluble carbonate or bicarbonate to water, from which the free and half

page_text: combined carbonic acid, and consequently the temporary hardness has already
been removed.
I also claim as a novelty in my process of softening water and as a part of
my Invention the use of slides with graduated scales for accurately adjusting
in the requisite relative proportions the size of the several openings through
which the hard water and solutions employed are made to pass before being
mixed together so as to readily and accurately proportion their necessary relative
quantities.
In witness whereof, I, the said Alfred Ashby, have hereunto set my hand
and seal, this Twenty-third day of May, in the year of our Lord One
thousand eight hundred and seventy nine..
ALFRED ASHBY. (L.S.)