Improvements in Salt Purifiers.
Year: 1893

page_text: Date of Application, 9th May, 1893-Accepted, 18+ July, 1893
COMPLETE SPECIFICATION.
Improvements in Salt Purifiers.
I, THOMAS CRANEY, of 624 Harrison Street, Bay City, County of Bay State
of Michigan, United States of America, 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 :-
This invention relates more particularly to an apparatus for purifying common
salt; and the object of my invention is to produce chemically pure salt by purifying
the common salt as produced by the known processes and sold in the market. This
salt contains often from 2 to 5 per cent. of impurities which are made up generally
of different chlorides, soluble in water, such as chloride of calcium and chloride of
magnesium and insoluble substances, such as earthy matter contained in the brine
from which the salt has been manufactured or foreign substances which has become
admixed incidentally in the course of manufacture.
To this end I have designed an apparatus in which I subject the salt to a
mechanical treatment which is generally sufficient to remove all the impurities
commonly found in salt and by means of which I have succeeded at a slight
expense to make salt almost chemically pure. At the same time my apparatus
enables me to make a fine grade of market salt from the large amount of waste
salt which owing to coloring matter or other foreign impurities is graded low and
applicable only to a commercial or agricultural uses.
My apparatus is based upon the fact that the impurities found in common salt
are not contained in the salt crystals but adhere only mechanically to the surfaces
of the crystal and may be removed by a process of washing accompanied by
mechanical agitation and separation by gravity, all as more fully hereinafter
described in connection with the accompanying drawings, in which―
Fig. 1 is an elevation of my apparatus embodying my invention.
Fig. 2 is a vertical central section through the purifying tank, showing the
devices for agitating.
Fig. 3 is a horizontal section on line x-x in Fig. 2.
Fig. 4 is an enlarged horizontal section on line y-y in Fig. 2.
A is the stand pipe preferably constructed of iron in a number of superimposed
sections bolted together to form a tight vessel for containing liquid. B is the
revolving shaft journaled in the axis of the vessel, which to this end is provided
with suitable cross-trees C at necessary intervals to form suitable bearings therefor,
the lower one of such cross-trees having a suitable step in which the shaft is
supported.
On the upper end of this shaft outside the vessel are applied means for revolving
the shaft, such as the pulley D on one side below the top of the vessel, the inlet
opening E is provided through which the salt to be purified is introduced, and some
distance above this inlet opening the overflow outlet F is located, which overflow
outlet is intended to keep the liquid in the vessel to the height thereto.
To the shaft B are secured the vertical series of agitators preferably formed of
radially arranged arms secured to a hub G, one of these hubs being shown in
detail in Fig. 4, in which a are the arms and b a set screw for holding the hub upon
the shaft.
Between the arms of the revolving agitators are secured stationary arms H
which project from the wall of the vessel towards the center and which arms pre-
ferably in number and form correspond with the arms of the agitator and are
secured at equal distances apart to vertical ribs I, formed or secured on the inside
of the vessel.

page_text: At the bottom this vessel communicates with a vertical trunk J which is pre-
ferably of less diameter than the vessel and which communicates at the bottom with
the lower end of the inclined conveyor. pipe K.
This inclined conveyor pipe extends from the bottom of the trunk J to some
distance above the level of the liquid in the vessel and contains a carrier or con-
veyer for removing the salt from the bottom of the trunk.
To this end I preferably employ an endless bucket chain L passing around
suitable sprocket wheels to the upper one of which power is conveyed in any
suitable manner, and which is also provided with means for tightening the bucket
chain. A similar bucket chain is arranged in the inversely inclined trunk or
carrier flue M to convey the salt from the place of delivery N to the top of the
inlet pipe O from which it is adapted to fall through said inlet pipe and opening E
at the bottom thereof into the vessel.
This bucket chain is also provided with suitable means for conveying power
to it.
P is a pipe for conveying brine or other washing solution into the trunk K from
a suitable source of supply.
In practice, the parts being arranged and constructed substantially as shown and
described, the mode of operation is intended to be as follows:
I preferably use for the washing solution common salt brine, such as is procured
from the wells and this I introduce through the pipe P, preferably by a continuous
feed. The course of flow is then down through the trunk K and through the
communication at the bottom thereof into the trunk J from whence it flows in an
upward direction through the whole pipe of the vessel to overflow again through
the opening F to a receiver. At the same time the salt to be treated is carried
by the conveyor device from the place of delivery at N into the top of the pipe O
from which it falls into the top of the vessel where it becomes suspended in the
brine which is contained therein to a distance above that opening. By its specific
gravity the salt is then compelled to gravitate towards the bottom of the vessel,
but during such passage it is caught up by the agitating device and given a
thorough treatment of washing during its descent to the bottom of the vessel.
The agitators produce an intimate mixing of the salt crystals with the washing
liquid which is thereby enabled to dissolve or absorb the soluble matter adhering
to the salt crystals and also hold the earthy matter or other admixtures thoroughly
in suspension, and as the direction of the washing fluid is in the direction opposite
to the course of the gravitating salt they will become separated and carried by the
flow to the top of the vessel and out through the discharge pipe, while the salt
freed from its foreign substance finally drops into the bottom of the vessel and is
carried out by the conveyor devices, during which time it is acted on by the
contrary flow of the washing liquid down through the trunk K. At the time it is
then brought to the surface above the washing liquid at the top it has practically
all the impurities eliminated and a superior grade of salt is obtained.
While have described no other washing liquid but brine I want it distinctly
understood that I do not intend to confine myself as the kind of liquid best adapted
depends conditionally upon the impurities which may be contained in the salt and
therefore the use of certain chemicals embodied in the washing liquid is within the
spirit of my invention.
It will be obvious that the washing liquid overflowing from the vessel need not
be wasted but after suitable treatment may be used anew.
The vessel is provided at the bottom with suitable discharge openings for the
purpose of cleaning or washing out the vessel when necessary.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :
1. In an apparatus for purifying salt, the combination of a vessel containing a
body of washing fluid and provided with an overflow, a supply for the washing

page_text: fluid, communicating with the vessel for maintaining a supply of fresh washing
fluid and circulating the same upward through the vessel and mechanical feed
devices for feeding the salt into the top of the vessel, mechanical devices for
removing the salt from the bottom of the vessel and a stirring device in the vessel.
2. In an apparatus for purifying salt, the combination of the vessel adapted to
contain a body of the washing fluid, an overflow for the same near the top of the
vessel, a settling chamber at the bottom of the vessel, an inclined trunk com-
municating with said settling chamber and extending above the level of the fluid
in the vessel, a conveyor in said trunk for removing the salt from the settling
chamber, a feed connection for the washing fluid into said vessel, means for feeding
the salt into the top of the vessel and an agitator submerged in the body of the
washing fluid in the vessel, substantially as described.
3. In an apparatus for purifying salt, the combination of the cylindrical vessel,
the agitator having arms secured to a revolving shaft and intermediate fixed arms
secured to the walls of the vessel, the settling chamber (J) at the bottom of the
vessel, the inclined conveyor trunk (K) communicating therewith and containing
the conveyor (L) the inlet (P) into said conveyor trunk for the washing fluid, the
overflow (F) from the vessel, and the feed for introducing the salt into the top of
the vessel, all arranged to operate substantially as described.
THOMAS CRANEY.
Haseltine, Lake & Co.,
45, Southampton Buildings, London, Agents for the Applicant.