Year: 1887

page_text: Date of Application, 19th Apr., 1887
Complete Left, 19th Jan., 1888
Complete Accepted, 24th Feb., 1888
I, GEORGE EDWARD DAVIS of 101 Great Clowes Street, Manchester in the county
of Lancaster, Chemical Engineer do hereby declare the nature of this invention to
he as follows:-
The amount of lime salts present in many sources of water supply, renders such
water very unfit for washing and cleansing, for feeding steam boilers, and many other
purposes of trade.
I have found that if tribasic phosphate of soda be added to such a water, the whole
well mixed and allowed to stand at rest for some time, that most of the lime and
magnesia salts are precipitated and may be removed.
In carrying out this invention the tribasic phosphate of soda is dissolved in a small
quantity of water, and added with agitation to the bulk of the water to be purified.
After the lapse of a few hours the lime and other impurities are precipitated and the
clear softened water may be drawn off for use.
The proportions to be used, must necessarily vary with the amount of lime salts
present in the water, but it may be stated that for such a water as the London supply
from the chalk about half-an-ounce will be sufficient to purify ten gallons of the
water.
The precipitate from the purified water may be collected & forms a valuable manure.
In several experiments I have made I find the moist precipitate contains about
forty per centum of tribasic phosphate of lime and about sixteen per centum of
carbonate of lime.

page_text: COMPLETE SPECIFICATION.
Softening and Purifying Water for Domestic and Trade Purposes.
I GEORGE EDWARD DAVIS of 301 Great Clowes Street Manchester, in the County
of Lancaster, Chemical Engineer and Consulting Chemist, 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 :-
Most natural waters contain lime or other substances which render some of them
unfit for use for trade purposes, and inconvenient for domestic use.
River-water, or brook-water, or rain water is of course an exception, and it is the
object of this invention to climinate most of the lime and other interfering substances,
so that well-water, or water containing lime and other substances may be used for
domestic or trade purposes with almost the same ease as the water from rivers or
brooks, or rain water.
In carrying out my invention I add to the water to be treated, tribasic phos-
phate of soda, preferably in a state of solution in water, & I mix this solution with
the water undergoing treatment until the one is well incorporated with the other.
The mixture made as beforementioned is then allowed to settle, whereupon the
lime salts fall to the bottom of the vessel mixed with other substances & the clear
water may be drawn off for use, or pumped away into a store tank.
The residue remaining in the tank or other vessel, may be used as a manure as
it contains a large quantity of phosphate of lime.
The quantity of tribasic phosphate of soda required will vary with the hardness of
each water to be treated; but a good guide for the proportion required to each
gallon of the water, will be, five times the amount in grains, of the hardness of the water
by Clark's scale, of crystallized tribasic phosphate of soda, that is to say a water of
ten degrees of hardness would require about fifty grains of tribasic phosphate of
soda per gallon, but where the hardness is of the quality called " permanent
hardness," about one half of this quantity only is necessary, or even less than this.
Having now particularly described and ascertained the nature of my said Invention
& in what manner the same is to be performed, I declare that what I claim is:
The treatment of water by means of tribasic phosphate of soda for the purpose
of softening and purifying the same, for domestic and trade purposes, substantially
as hereinbefore described, and the use of tribasic phosphate of soda for that
purpose.
Dated this 18th day of January 1888