Improvements in Means or Apparatus for Obtaining Brine from Rock Salt.
Year: 1892

page_text: Date of Application, 10th Oct., 1892
Complete Specification Left, 7th July, 1893-Accepted, 19th Aug., 1893
PROVISIONAL SPECIFICATION.
Improvements in Means or Apparatus for Obtaining Brine from
Rock Salt.
I THOMAS WILSON STUART of 15 Windsor Terrace Newcastle upon Tyne
Manager of Chemical Works do hereby declare the nature of this invention to be
as follows:-
In the known methods of producing brine on the top surface of a bed of rock
salt, a cavity is formed which causes or is liable to cause subsidence of the surface
immediately overlying this cavity. The object of my invention is to prevent or
postpone this subsidence for which purpose I dissolve the bed of rock salt from
below instead of at the upper portion which upper portion remains as a roof to
support the overlying strata.
In carrying out my invention a pipe technically known as a "drive pipe" is
driven from the surface into the bed of rock salt and a borehole is then drilled'
through the drive pipe from the surface to the bottom of the bed of rock salt.
The drill is then withdrawn and a lining tube perforated for any desired distance
from its lower end is inserted. Inside this lining is inserted the suction tube of a
pump the said tube being perforated for any desired distance from its lower end
and the relative diameters of the pump tube and the lining tube being such as to
provide between them an annular space in which is placed another tube perforated
at the bottom. In this tube is a float having attached to it a wire cord or the like
reaching to above the top surface, where an indicator may be fixed in order to
shew the position of the float and consequently the depth of water in the well.
When the brine well is thus fitted ready for working, water is conducted to the
mouth of the well through a pipe provided with a valve or stop cock by which the
water may be admitted as required into the annular space whereby only the lower
portion of the salt bed may be dissolved leaving the upper portion of the bed of
any desired thickness as a roof to prevent subsidence of the surface. Suppose for
example it is desired to produce brine from a bed of rock salt 400 feet thick and it is
intended to dissolve the lower portion to the extent say of 100 feet thick and leave
say 300 feet as a roof, the supply of water to the annular space between the pump
and lining tubes should be so regulated by the aid of the float that it will only come
It will thus be
in contact with the lower 100 feet in height of the rock salt.
obvious that if the upper level of the water is kept by the aid of the float at a
point not exceeding 100 feet (or any other convenient distance from the bottom of
the bed) the upper portion of the rock salt above the water line will not be
dissolved, and will always remain as a roof to prevent subsidence of the surface.
The inflow of water from the surface through the annular space between the
lining tube and pump tube, and the withdrawal of saturated brine through the
pump tube are easily adjusted to each other, and the level of the water kept at
the desired distance from the bottom of the bed by means of the float and '
indicator already described.
Dated this 10th day of October 1899
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, London, W.C., Agents.

page_text: Improvements in Means or Apparatus for Obtaining Brine from
Rock Salt.
I, THOMAS WILSON STUART of 15 Windsor Terrace Newcastle upon Tyne
Manager of Chemical Works do hereby declare the nature of my invention and
in what manner the same is to be performed to be particularly described and
ascertained in and by the following statement :-
In the known methods of producing brine on the top surface of a bed of rock
salt a cavity is formed which causes or is liable to cause, subsidence of the surface
immediately overlying this cavity. The object of my invention is to prevent, or
postpone this subsidence for which purpose I dissolve the bed of rock-salt from
below instead of at the upper portion, which upper portion remains as a roof to
support the overlying strata.
In carrying out my invention a pipe, technically known as a "drive-pipe"
is driven from the surface into the bed of rock-salt and a bore hole is then
drilled through the drive pipe from the surface to the bottom of the bed of
rock-salt.
The drill is then withdrawn and a lining tube, perforated for any desired
distance, from its lower end, is inserted. Inside this lining tube (constituting an
Artesian well) is inserted the suction tube of a pump, the said tube being perforated
for any desired distance, from its lower end, and the relative diameters of the
pump tube and the lining tube being such as to provide between them, an annular
space in which is placed another tube perforated at the bottom. In this tube is a
float having attached to it a wire, cord or the like, reaching to above the top
surface where an indicator may be fixed in order to shew the position of the float,
and consequently the depth of water in the well.
In cases where water or rock head brine is found in drilling the well it is
necessary to fill up the space between the inside of the borehole, and the outside of
the lining pipe with cement, which effectually prevents either the water or rock
head brine from passing down outside the lining tube. In this manner any solution
of the rock salt on the surface of the bed, and any subsidence of the surface, are
effectually prevented.
The accompanying drawing will illustrate the way in which the apparatus may
be arranged for the purposes of my invention.
A is the surface of the ground and B the saliferous bed, C is the lining tube or
well perforated at c. D is the suction tube of the pump the said tube D being
perforated at d. E is a tube perforated at bottom and containing a float e con-
nected by a wire with an indicator moving over the scale e*. F is a water
supply pipe provided with a valve f. shews the drive pipe.
When the brine well is fitted ready for working as hereinbefore described, water
is conducted to the mouth of the well through the pipe F and valve or stop-cock f
by which the water may be admitted as required into the annular space between the
well C and tube D whereby only the lower portion of the salt bed may be dissolved
leaving the upper portion of the bed of any desired thickness as a roof to prevent
subsidence of the surface. Suppose, for example, it is desired to produce brine
from a bed of rock-salt 400 feet thick, and it is intended to dissolve the lower
portion to the extent say of 100 feet thick and leave say 300 feet as a roof the
supply of water to the said annular space should be so regulated by the aid of the
indication of the position of the float e that the water will only come in contact with
the lower 100 feet in height of the rock-salt. It will thus be obvious that if the
upper level of the water be kept, by the aid of the indication of the position of the
float, at a point not exceeding 100 feet (or any other convenient distance) from
the bottom of the bed the upper portion of the rock-salt above the water line will

page_text: not be dissolved and will always remain as a roof to prevent, or postpone, subsidence
of the surface.
。
The inflow of water from the surface through the annular space between the
lining tube and pump tube and the withdrawal of saturated brine through the pump
tube are easily adjusted to each other and the level of the water kept at the
desired distance from the bottom of the bed by the aid of the float and indicator
already described.
I have described the application of my invention to the case of Artesian wells but
it is obvious that the invention is applicable in other cases as for example the bed
of rock-salt may be dissolved from below in the following manner. A shaft is
sunk to the bottom of the bed, and from the bottom of this shaft at or near the
bottom of the bed, a horizontal gallery is cut in the solid rock-salt to any required
length. A borehole is then drilled from the surface into the end of the said
gallery, and water is introduced which flows down and along the said gallery
and becoming saturated with brine is pumped up from the shaft. When it is
intended to dissolve the lower portion of the bed 100 feet from the bottom
or any other convenient height for the purpose of leaving a thick roof of
rock salt it is obvious that the above described float arrangement is applicable for
the purpose of enabling the level of the water to be maintained at any desired
height from the bottom of the bed. The arrangement of the float apparatus in the
borehole down which the water is bored, in this case is precisely similar to that in
the Artesian well already described.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed 1 declare that what I
claim is :-
1. In obtaining brine from rock-salt means, substantially as hereinbefore described
for dissolving only the lower portion of the saliferous bed leaving the upper portion
of such bed undissolved.
2. In apparatus for obtaining brine from rock-salt an arrangement of float and
indicator for enabling the level of water or brine at the lower part of the saliferous
bed to be regulated substantially as herein before described.
3. An apparatus for obtaining brine from rock salt the said apparatus being
constructed or arranged substantially as hereinbefore described and illustrated in
the accompanying drawing.
Dated the 7th day of July 1893.
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, London, W.C., Agents.