Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates to d method and apparatus for mixing solid
and liquid substances.
Mixing solid and liquid substances is mostly accomplished in
a stirring apparatus which usually comprises a tank wherein a stirrer rotates.
Solid substances and liquids are, for example, mixed when a sugar solution
is prepared.
Ilowever, it is a disadvantage of such a simple stirring apparatus
that the centrifugal forces tend to drive the solid particles to the wall
of the tank where they settle in a compact mass. This makes the mixing pro-
cedure slow and not sufficiently efficient. Moreover, aEter mixing the tank
has to be emptied ~ind refilled completely.
The production oE such a solutiorl is thereEore discoll~inuous
which entails a severe loss oE time.
It is thereEore all object oE a broacl aspect oE l:hiS illVellt iorl tcl
provide a method and apparatus for mixing solicl substances with liquids in
such a way that the ready mixture is obtained in a continuous flow.
By one broad aspect oE this invention, a method is provided Eor
mixing and dissolving solid and liquid substances in a mixing/reactor zone
having an inlet zone at one end thereof and an outlet zone at the opposite
end thereof, the method comprising the steps of: keeping both the solicl
and liquid substances to be mixed continuously in a constant circulation in-
side an in-line mixing zone within the mixing/reactor zone, using an exter-
nal source of mixing energy to
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maintain a mixture or solution; continuously internally recirculating a
portion of the mixture or solution along with an addition portion of the
mixture or solution from an external source in a separate concentric
circulating zone within the mixing/reactor zone; continuously withdrawing a por-
tlon of the recirculating mixture or a portion of the solution from the concen~ric
zone through an annular outlet connection zone leading to the mixing/reac-
tor zone and thence through an annular inlet connection zone leading to the
concentric zone; continuously discharging a solution from the mixing/
reactor zone through a separate annular discharge zone and through outlet
zones to a level-controlling discharge zone; and (e) continuously and con-
trollably supplying an amount of both the solid ancl the lLquLcl suL~tances to
the mixing/reactor æone, tha supplied amount baing ec~ l to the dischargad
solution withdrawn throucJh the discharga zono.
By another aspect of this invention, a loop reactor is provided
comprising a substantially horizontal cylindrical vessel; a conduit
arranged in the vessel concentrically therewith and provided with means
defining an annular space which communicates with a mixing space between the
conduit and vessel and with at least one outlet opening at one end of the
, conduit; an outlet duct connected to each outlet opening; liquid inlet means
arranged at the other end of the conduit concentrically therewith; filling
means arranged at an upper portion of the vessel; and a pump for circulat~
ing liquid through the reactor, the pump being connected externally of the
vessel at one side to the outlet duct and at the other side to discharge
means to a return duct connected to the inlet means to provide a recircu-
latory flow from the conduit, through apertures to an outlet annular zone
at the end of the vessel to the mixing space and thence to an inlet
annular zone back to the conduit, and a discharge flow from the mixing space
to the annular-space-defining means and thence to outlet tubes connected to
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the discharge means.
By a variant -thereof, the loop reactor includes level regulating
means associated with the filling means and operatively connected to the
discharge means to co-ordinate the rates of filling and discharge.
By anothe.r aspect of this invention, a loop reactcr is provided
for mixing and dissolving solid and liquid substances, .the reactor compris-
ing: a tube-shaped reactor housing supported horizontally on a foundation;
inlet means at one end and outlet means at the opposite end of the reactor
housing; a guide tube in the reactor housing providing the sole connection
to the inlet means and also defining an outer annular mixing chamber between
the guide tube and the inner wall o:E the reac-tor housing; a tube portion
surrounding a por-tion of the guide -tube and being connected to the guide
tube at the end adjacent the out:Let means, the ~ube porti.on ancl the gu:ide
tube defining an inner ann~Llar chalrlber between them, the :Lnner annul.a:r space
being connected to the mix:ing chamber.by :inlet open:ings t.hro~lgll wh:i.c}l tlle
solid and liquid substances enter into the inner annular chamber and bei.ng
the sole connection to the outlet meansi a filling socket connected to the
upper side of the r.eactor housing for filling both the solid and the liquid
substances into the reactor housing; at least one level con-trol indicator
in the filling socket for opening and closing -the socket and thereby
regulating the level oE the solid and liquid subs-tances i.n -the reactor; a
PiPe connec-tion between -the inner annular chamber and the reac-tor housing
outlet means; a circulating pump in the pipe connection :Eor pumping the mix-
ture of the solid and liquid from the outlet means to the inlet means and
for providing internal recirculation from the discharge zone of -the guide
tube to flow around the pipe connection and through apertures directly
connecting the discharge zone of the guide tube to the outer annular mixing
char~ber recirculation at the end of the tube-shaped reactor being enabled
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by annular spaces between the tube por-tion and the internal surface of
the tube-sha ed vessel; and a level controlling discharge valve connected
to the pipe connection for discharging the final solution.
By a variant thereof, the reactor fur-ther includes means connecting
the discharge valve and the ~evel control indicator so that upon opening of
the discharge valve for discharging the ~inal solution, the level control
indicator is simultaneously operated to feed a corresponding quantity of
substances into the reactor.
One type of reactor which, aEter slight modifications, is
basically suited for performing the invented method is, for example,
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described in the U.S. Patent No. 4,037,~25 issued July 26, 1977 to Herwig
Burgert.
Such a reactor which would be slightly modified to provide an
appara-tus of an aspect of this invention comprises a tube-shaped reac-tor
housing supported horizontally on a foundation. The housing has inlet
means in -the form of an injec-tion nozzle at one end and outlet means at
the opposite end. A guide tube in the reactor housing defines a mixing
and dissolving chamber between the guide tube and the inner wall of the
reactor housing. A further short tube surrounds the guide tube and is
connected to the guide tube at one end adjacent to the reac-tor outlet
means. A filling socket is connected to the upper side of the reac-tor
housing for filling the substances into the reactor. A pipe line inter-
connects the reactor housing outlet means and inlet means. A circulating
pump is part oE the pipe connac-tion for pumping the mixture ~rom the out-
let: means back to the inlet means. A dischar~Je va:Lve is p~rt o~ t:he p;pe
connection Eor withdraw:inc~ part of the ready mixture from the reLIctor, ar
a control valve is part of the filling socket. The discharge valve and
the control valve are so interconnected -that the same quantity of sub-
stances is always fed to the reactor tha-t is withdrawn by way of the dis-
charge valve.
In the accompanying drawing, -the single figure shows schematical-
ly a loop-type reactor according -to one aspect of -this inven-tion for per-
forming the method of another aspect oE-this invention.
Referring now to the drawing, the reactor comprises a cylindri-
cal reactor housing 1, within which a guide tube 2 is concentrically
arranged. Through part of its length, the guide tube 2 is provided with a
double wall having an inner wall 4 and an outer wall 3. Both walls de-
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fine between them an annular hollow space with an inlet 6 at one end of theouter wall 3. The other end of the outer wall 3 is conneeted to the inner
wall 4. mrough this connection tubes 7 extend to the reactor ou-tlet 10.
On ~he upper side of the reactor housing 1 a filling soeket 8 is
provided. A pipe 9 ends in this filling socket. Through the filling
socket the solid substances to be mixed and dissolved are introduced into
the reactor while the liquid substances enter through the pipe 9. A control
valve 17 is part of the socke-t 8. By means oE this control valve 17, the
quantity of substances filled in-to the reactor is regulated.
On the left-hand side of the drawing there is an inlet opening
in the reactor housing 1, including an injec-tion nozzle 1~. Pipe connee-
tions 12, 13 interconneet -the outlet 10 of the reactor with the inlet. In
pipe connections 12, 13 a pump 11 is arrancjed which ca~lses the solut:ion to
eireulate eonstantly through the reaetor and pipes 12, L3.
A diseharge valve 16 is eonneeted with pipe :L5 to thc pi~?e L3
Eor emptying the ready so]ution into appropriate tanks, bottles or pipes
(not shown).
A suitable connection 19 (shown in broken lines) exists be-tween
the discharge valve 16 and the con-trol valve 17.
When -the reactor is filled and in operation the circulating pump
drives the substances through the reaetor and from there through the pipe
connections 12, 13, back into the reactor by way of -the nozzLe 1~. This
causes the substances to be thoroughly mixed and dissolved.
Upon opening c>f the discharge valve 16, the Final sol-ltion flows
into the discharge pipe 15. The control valve is so regulated through
connection 19 that, at the same time, new substances are admitted -to the
reac-tor to an extent that they will replace the discharged quantity of the
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final solution.
A faucet 18 is provided at the lower side of the reactor housing
for completely emptying the reac-tor, if desired.
In o,her words, in operation pump 11 becomes operational the
moment all of the reactor housing 1 is filled and pump 11 then injects
the mixture or solution -through the nozzle 14 into the guide tube 2. This
initiates the circuiation of the mixture or solution because the mixture
or solution, as shown by the arrows, is forced at the right of the tube 2
between the walls 1 and 3. Pipes 7 pass through the cover and the mixture
or solution can move through besides the pipes 7. Thereupon the mixture
or solution between l and 2 at the le~t end is a~ain i-orced into
tube 2. At tl-e same tLme, th~` rnixtur~ or sr-lution nlso (ullc'ls al 6 nrld is
sucked :in through 7 and 10 by tho motor and ~lgain is mcldo to cixclllat:c
through the nozz:Le 1~ as long as valve 16 is closed. ~Ic~n~ aEtor !;C)lllC!
time of circulation the mixture is a -true solution in which the solids
are completely dissolved in the liquid solvent, the discharge valve 16 is
opened to drain off the final solution. Depending on how much valve 16 i5
opened, the solution can be simultaneously pumped through the pipe 13.
