FIELD OF THE INVENTION:
The present subject matter described herein, relates to an automatic device for
condensing solvent vapours in soxhlet apparatus, or in particular to a fully
automatic device with closed loop water circulating system and also a
methodology to nullify the requirement of using running live water for the
separation of soluble components from solid part of test samples.
BACKGROUND OF THE INVENTION:
The soxhlet extraction apparatus is a laboratory apparatus and is used for
extracting solvent soluble components from any material. This apparatus is
used to separate different components for example resin & accelerator from any
test sample.
The solvent is heated to reflux. The solvent vapour travels up a distillation arm,
and floods into the chamber housing the thimble of sample material. The
condenser ensures that all the solvent vapour cools, and drips back down into
the chamber housing the sample material. The chamber containing the sample
material slowly fills with warm solvent. All soluble components of the material
dissolves in the warm solvent. When the Soxhlet chamber is almost full, the
chamber is emptied by the siphon. The solvent is returned to the distillation
flask. The thimble ensures that the rapid motion of the solvent does not
transport any solid material to the distillation flask. This cycle may be allowed
to repeat many times, over hours or days.
During each cycle, a portion of soluble component dissolves in the solvent.
After many cycles the desired compound is concentrated in the distillation
flask.
Conventionally the method of operation of earlier Soxhlet extractor was manual
in nature. The solvent vapours were condensed by continuously flowing live
running water through the condenser, due to which huge amount of water
(~90Lt/hr) was flushed away in to the sewage and got wasted. The system was
water supply dependent and could not be run in case of water supply is cut off.

The system also needs periodic monitoring in order to avoid any fire accident or
sample burn in case of faults.
Fig 5 illustrates the conventional soxhlet extractor wherein the live running
water is required for condensation of solvent vapour.
In this method of the operation of soxhlet extraction apparatus, the vapours
were condensed by flowing a continuous flow of live running water through the
apparatus, due to which huge amount of water got wasted. As the extraction
process is long time taking process of about 6 hrs to 12 hrs, due to which
approximately 90 Lt per hour of water (Approx. 1080 Lt in one test) was wasted
during the operation.
Hence, it can be concluded that the extraction process was completely
dependent on the supply of live running water. In the absence of supply of live
water, the system cannot be used for conducting the test.
Generally, the extraction process continues for 6 to 12 hrs and constant
manual monitoring is required during the time period as the conventional
testing is manually operated.
Sometimes, in case of any faults, the supply of live water got stopped during
the test and hence, the extraction process got interrupted.
The consequence of sudden interruption of test is very critical. In this case the
solvent vapours will not get condensed and all the solvent gets evaporated
completely due to which sample got burnt or damaged and eventually can even
catch fire if not monitored well in time.
Further, the duration of test run could not be recorded.
Hence, there is always a long felt need to develop an innovative device utilizing
a fixed amount of stored water to condense solvent vapours in soxhlet
apparatus which can reduce the wastage of water substantially and where the
manual dependency can also be nullified.

The present invention meets the long-felt need by providing a device which is
completely automatic and removes the dependency on live running water for
performing any essential test.
SUMMARY OF THE INVENTION:
A device for water cooling in soxhlet extraction apparatus comprising: a cooling
unit; and a control unit; wherein said cooling unit further comprises: a
reservoir tank for storing water; a submersible pump placed in the tank; a
cooling tower along with a helical copper tube for cooling down of hot water
coming from Soxhlet Apparatus; two water sensing probes; characterized in
saving water and cooling the hot water coming out from the condenser of
Soxhlet Apparatus by dissipating approx. 69% of the heat pickup during the
solvent condensing process, wherein the control unit further comprises of one
water sensing circuit, timer circuit, time counter and contactor; characterized
in providing the safety features to the system developed by controlling the
heaters and timer as per the electrical signals received from the water sensing
circuit.
OBJECTS OF THE INVENTION:
It is therefore the principal object of the present invention to provide a novel
device for solvent condensing system in soxhlet apparatus, where requirement
of continuous flow of live running water is nullified and thereby saves huge
amount of water.
Another objective of the present invention is to provide a novel device for water
cooling system in soxhlet apparatus, where all the operations are fully
automatic, circuit controlled and thereby diminishes the risk of catching fire
and sample burning in case of any faults.
Yet another object of the present invention to provide a novel device for soxhlet
apparatus, wherein the extraction process may be performed overnight in a
single day and hence, the duration of whole testing has been reduced.

Further object of the present invention is to provide a novel method for soxhlet
apparatus, where all the compounds like heater and time are electronically
controlled.
Another object of the present invention is to provide a novel method for soxhlet
apparatus, which does not need any external water source during extraction of
sample.
Yet another object of the present invention to provide a novel method for
soxhlet apparatus, where manual monitoring is not required.
Further object of the present invention to provide a novel device for soxhlet
apparatus, which records the duration of test run.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING:
It is to be noted, however, that the appended drawings illustrate only typical
embodiments of the present subject matter and are therefore not to be
considered for limiting of its scope, for the invention may admit to other equally
effective embodiments. The detailed description is described with reference to
the accompanying figures. Some embodiments of system or methods in
accordance with embodiments of the present subject matter are now described,
by way of example, and with reference to the accompanying figures, in which:
Fig 1 illustrates the fully automatic device for water cooling in Soxhlet
apparatus.
Fig 2 illustrates the control unit block diagram.
Fig 3 illustrates the snapshot of the control unit.
Fig 4 illustrates the snapshot of the new system developed for Soxhlet
extraction apparatus.
Fig 5 illustrates the conventional arrangement used for condensing solvent
vapous in Soxhlet apparatus.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS:
The subject matter disclosed herein relates to an automatic closed loop water
circulating system for condensing solvent vapours in soxhlet extraction
apparatus and methodology associated therewith. Two important units such as
a cooling unit (1) and a control unit (2) are provided alongwith the basic
structural components of the soxhlet extraction apparatus (as shown in fig 1).
Soxhlet Extraction is used to separate soluble components from a solid. The
basic objective of soxhlet extraction processes is to dissolve as much of the
soluble components as possible with a specific amount of solvent. This is
achieved by constantly vaporizing the solvent and allowing it to drip into the
sample from a condenser. The extracted component accumulates in the
distillation flask (15).
Basic components of soxhlet extraction apparatus also comprises a condenser
(13), an extractor (14) and a distillation flask (15).
The Condenser (13) cools the solvent vapour and causes it to condense. The
ring type condenser is used to increase the surface area of condenser tube for
heat transfer.
Extractor (14) is used to hold the solid sample and allow the condensed solvent
to saturate and pass through, thereby extracting the solute present in the
sample.
The distillation flask (15) holds the solvent pool and serves as a reservoir for the
extracted solute material present in the sample.
The cooling unit (1) is basically a closed chamber, which comprises a reservoir
tank (3) where water is stored at room temperature. A water submersible pump
(4) is placed in the reservoir tank (3). A cooling tower (5) is also present in
which a helical copper tube (6) is embedded. The helical copper tube (6) acts as
a heat exchanger during the travelling of hot water and often helps maximizing
the heat loss during the travel.

The copper coil (6) is wrapped with a cotton jacket outside. The water exiting
the coil is showered over the top of the heat exchanger through a recirculation
pipe (7).
Fig 4 also illustrates a snapshot of the soxhlet extraction apparatus as claimed
hereinafter.
According to an implementation of the present subject matter a control unit (2)
is also provided to take care the safety aspects of the system.
Fig 2 and 3 illustrate the control unit (2) which comprised of water sensing
circuit (9), timer circuit (10) and timer counter (11) and a contactor (12). The
timer will measure the time during which the Heaters were in ON condition.
As the water sensing circuit (9) receives electrical signals from the probes, the
circuit actuates the contactor (12). When the contactor (12) is switched ON it
further actuates the timer unit and both the heaters.
In other embodiment of the present subject matter, when the water
submersible pump (4) is switched on, the room temperature water, stored in
the reservoir tank (3) moves from the tank to the outer portion of the condenser
tube through inlet pipe (16) and condense the solvent vapours.
After condensing, the hot water comes out of the condenser (13) and enters into
the inlet of cooling tower (5).
The hot water is first passed through a helical copper tube (6) of cooling tower
(5). During this stage, the hot water travels approx.10 meter starting from inlet
to the outlet of the coil.
A calculation of approximate distance travelled by water in the copper coil is
given below:
No of turns: 27
Circumference of one helical coil = 40 cm
Total water travel in coil of cooling tower (5) = 24 x 40 = 1080 cm (~10 m)

Further, two water sensing probes are mounted in the path of falling water. The
water sensing probes gives electrical signal to the water sensing circuit (9) and
actuates the circuit and thereby actuation of contactor (12) occurs leading to
further switch on mode on both heaters and timer unit.
When the water is at the highest altitude in showering position of cooling tower,
both the heaters (17) and the time counter are switched ON.
Hence, the heaters will get ON only when the water is circulated through the
soxhlet condenser tube in order to avoid fire accident or sample burn and
thereby enhancing the safety aspect of the whole soxhlet apparatus.
The showering of water takes place on the top of the heat exchanger and
facilitates travelling of water all over the surface of cotton jacket and eventually
cools down the hot water inside the coil.
The purpose of cotton jacket is to maximize the time of travel of water from top
to the bottom of the jacket. More will be the time of travel and more will be the
heat transferred as a result faster will be the water cooling.
During this stage the water drips drop by drop between the cotton mesh,
thereby increasing the surface area of water. Due to this slow movement of
water and more water surface area exposure to atmosphere, the efficiency of
heat exchanger unit is increased substantially.
The water flowing through the cotton jacket is cooled naturally through air
convection. The cooled water is then collected in the base portion of cooling
tower (5) and then is passed down to water reservoir through sieve. The sieve
will filter the solid impurities from the water. The water finally returns back to
the reservoir tank (3), thus completing its cycle. Reservoir tank (3) is having
water Leven Indicator feature to show the level of water in tank as the tank is
opaque in nature.
Hence it can be asserted that the new device for water cooling system for
soxhlet apparatus saves precious water which was preciously got wasted during

the operation of test as the new system of water cooling already comprises
stored water source and does not dependent on live water supply.
Further, all the components of the novel water cooling device such as heater,
submersible pump and timer are electronically controlled and thereby resolves
the issue of human dependency.
As the device is automatically controlled, it enhances the safety requirement by
minimizing the risk of catching fire and burning of samples in case of faults.
CALCULATION OF PERCENTAGE OF HEAT DISSIPATED BY COOLING
TOWER
Rate of Enthalpy rise of reservoir tank (3) water per hour (without using the
cooling tower)

_
Cp = Speafic heat of water (Unit: J/kg'Q
ti = Initial Time (tl = 0 for Initial measurementeJ
t2 = Time LAirdtkvi ufiTitsdturtjrneil
~2 = Temprrature at wattt at flnv: r?
~1 = Temp«at