H_ M_ WElR
`Oct. 18, 1949.«
`PROCESS AND APPARATUS FOR MANUFACTURING GELS
`
`2,485,249
`
`Filed‘Feb. 19, 1944
`
`2 Sheets-Sheet l
`
`346/
`/
`
`5750/1
`
`T410
`
`20'0"
`
`44
`
`6mm/wifi
`
`l
`
`SNF Exhibit 1025, Page 1 of 7
`
`

`
`Oct. 18, 1949.
`
`.
`
`H_ M_ WElR
`
`2,485,249
`
`PROCESS AND APPARATUS FOR MANUFACTURÍNG GELS
`
`Filed Feb. `19, 1944
`
`2 Sheets-Sheet 2
`
`é .
`
`if
`
`46
`
`@gm @fh-b VÁW
`
`SNF Exhibit 1025, Page 2 of 7
`
`

`
`Patented Oct. 18, 1949V
`
`2,485,249
`
`OFFICE
`
`UNITED STATES PATENT
`2,485,249
`PROCESS AND APPARATUS FOR
`MANUFACTURING GELS
`Horace M. Weir, Wynnewood, Pa., assignor to
`Chemical Corporation, Baltimore,
`The Davison
`Md.
`Application February 149, 1944, Serial No. 523,163
`(Cl. 23--182)
`3 Claims.
`
`2
`ñcation and illustrated in the accompanying
`drawings.
`In practicing the invention, the selected in
`gredients, such as solutions of sodium silicate and
`sulfuric acid, are fed under pressure to a mixing
`zone where they are mixed to form a hydrosol.
`The hydrosolis forced under pressure to a setting
`or gelling zone and caused to travel through said
`zone while undergoing the process of setting or
`gelling. The hydrogel product from the zone is
`extruded through a sizing grid and subjected to
`means for cutting the extruded filaments in a
`direction at right angles to the direction of ex
`trusion. The discrete particles of regular form
`are caused to move downward through a washing
`zone against a slowly rising flow of wash water.
`Gel particles which ultimately reach the lower
`portion of the washing zone are continuously re
`moved therefrom or are removed intermittently
`at short intervals. The salt and acid-ladened
`wash water forced through the moving gel bed
`to the top thereof is continuously discarded at a
`point near the location where the gel particles
`enter the washing zone.
`An important feature of the process resides
`in extruding the hydrogel from the setting or
`gelling chamber directly into and beneath the
`level of the wash water of the washing zone or
`into other suitable washing liquids. I thus obtain
`the cushioning eñ'ect of a liquid on the gel frag
`ments and thus prevent the fragile sized hydrogel
`from being abraded or reduced by shock below
`the optimum size which has been imparted by
`the sizing mechanism.
`In order to facilitate an understanding of the
`present invention, reference is made to the ac
`companying drawings, in which:
`Figure 1 is a diagrammatic illustration of one
`form of apparatus which may be used to carry
`out the process in accordance with the present
`invention.
`Figure 2 is a plan view of a modified form of
`extrusion grid.
`Figure 3 is a sectional view taken on line 3-3
`(cid:173) of Figure 2, and is an exaggerated showing of the
`taper of the grid plates.
`Figure 4 is a plan view of a grate employed in
`the washing tank.
`Figure 5 is a sectional view of the grate taken
`transversely of the movable shafts thereof.
`Figure 6 is a sectional view of a setting or gell
`ing tank embodying a modified form of the pres
`ent invention.
`In the following description of the present in
`vention reference is made to the preparation of
`
`l
`This invention relates to the manufacture of
`gels, and more especially to a process and ap
`paratus suitable for the continuous manufacture
`of oxide gels.
`Oxide gels, such as silica gel, can be made, for
`instance, by reacting solutions of an alkali metal
`silicate, such as sodium silicate, with an acid,
`such as sulphuric acid, to produce a hydrosol
`which upon setting will form a hydrogel. It is
`possible to effect the setting of the hydrosol to
`form a hydrogel either in batches or continuous
`ly. In the latter procedure the hydrosol may be
`passed through a setting zone, in which setting of
`the hydrosol to a hydrogel will take place during
`'passage therethrough.
`The present invention resides in the treatment
`and regulation of the gel-forming materials, the
`control of the gelling operation, treatment and
`handling of the hydrogel formed, washing of the
`gel, and control and handling of the gel during
`and after washing. In addition, the present in
`vention embraces apparatus suitable for effecting
`the manipulations above mentioned.
`An object of this invention is to control the
`flow of a hydrosol and a hydrogel resulting from
`the setting or gelling thereof through a setting
`or gelling zone.
``
`A further object of this invention is to control
`the ñow of a hydrosol and a hydrogel resulting
`from the setting or gelling thereof through a
`setting or gelling zone by regulating the admis
`sion of hydrosol or gel forming materials to the
`gelling zone.
`It is also an object of this invention to re
`strict the discharge of the hydrogel from the gell
`ing zone by extruding the same through tapered
`orifices.
`An additional object of this invention is to ex
`trude or discharge the hydrogel from the gelling
`.zone directly beneath the surface of a wash liquid.
`Another object of the present invention is to
`provide a process and apparatus for continuous
`ly forming and washing a hydrogel to produce a
`uniformly sized product under conditions which
`are controllable and can be held constant.
`The present invention also has for an object a
`method and apparatus for the control, treatment
`and handling of hydrogel forming materials be
`fore, during, and after gelling and washing.
`Still another object of the invention is to pro- .
`duce washed hydrogel with minimum labor costs.
`With these and other objects in view which
`will appear more fully hereinafter, the present
`invention resides in the steps and procedures, and
`. the parts and combinations described in the speci
`
`10
`
`15
`
`30
`
`40
`
`SNF Exhibit 1025, Page 3 of 7
`
`

`
`2,485,249
`
`15
`
`20
`
`10
`
`silica gel from solutions of sodium silicate and
`sulphuric acid by way of example, but it should
`be understood that the process and apparatus
`may be adapted to the production of any oxide
`gel.
`As illustrated diagrammatically in Figure 1 of
`the drawings, apparatus suitable for carrying out
`the present invention may comprise tanks I and
`2 for the storage of aqueous solutions of sodium
`silicate of predetermined concentrations.
`Tanks I and 2 are connected by means of
`suitable valve conduits with a source. of sodium
`silicate which is fed to the tanks as required.
`The discharge outlets of the tanks I and 2 are
`connected by suitable valve conduits with the in
`take of a pump 3 which forces the silicate solu
`tion under pressure through a‘valved conduit 4
`through a coil 5 of a heat exchanger 6 and thence
`into a mixer l. Means are provided for the flow
`of the silicate solution through the conduit 4 so
`that the same may by-pass the coil 5 and the heat
`exchanger 6.
`As illustrated in,the drawings, the apparatus
`also includes storage tanks 3 and S in which may
`be stored suitable supplies of an aqueous sul
`25
`phuric acid solution of desired concentration. As
`indicated, sulphuric acid solution may be Sup
`plied to the tanks through suitable valved inlets
`and withdrawn from the tanks'through valved
`conduits connected with the intake of a pump
`Iii. Sulphuric acid solution Withdrawn from the
`tanks by the pump It is forced upwardly through
`the valved conduit II through a coil I2 in the
`heat exchanger `6 and thence to the mixer 'I. As
`in the case of the coil 5, coil I2 may also be by
`passed in the passage of the acid solution up
`through the conduit II. The by-pass valves in
`the conduit 0l for the flow of the silicate solu
`tion and in-the conduit II for the flow of the
`acid solution may be adjusted as desired to
`properly distribute the flow partially through the
`coils 5 and I2 and partially through the by
`passes.
`The heat exchanger 6 may be of any desired
`construction and vmay be equipped with means
`for heating or cooling the solutions passing
`through the coils 5 and I2. This heat exchanger
`may be of the evaporative type in which the tem
`peratures of the solutions in the coils 5 and I2
`are raised or lowered as desired. This unit may,
`if desired, be replaced by a heating or a com
`bination heating and cooling unit of any selected
`type.
`Pumps 3 and I0 may be of the metering type
`so that predetermined proportions of sodium '
`silicate and acid solutions may be pumped to the
`mixer l'. As indicated, the mixer 1 is provided
`with an impeller I3 which is driven by an out
`side source of power, not indicated. The solu
`tions introduced into the mixer ‘I are thoroughly
`agitated so that intimate mixing is eifected to
`produce a hydrosol.
`As an example of a satisfactory operating pro
`cedure, the ratio of silicate solution to acid may
`be 1 part by weight of 25° Be. aqueous sodium
`silicate solution to 1.05 parts by weight of 23° Bé.
`aqueous sulphuric acid solution. It is convenient,
`but not necessary, to use metering type pumps
`to maintain the above ratio of reagents or any
`other desired constant ratio. I may, however,
`choose to use ñow controllers, or other instru
`' ments well known in the art and adapted to the
`maintenance of a specified ratio of reagents.
`After mixing of the solutions, the resulting
`hydrosol may be forced by the combined pres
`
`4
`sure of the pumps 3 and Il) through a line I4 to
`a second heat exchange unit I5, thence through
`line lâ into the upper part of the setting or gelling
`chamber Il. Heat exchange unit I5 is of the
`type well known in the art in which a heating
`fluid is arranged to flow in heat exchange rela
`tionship with the material stream being proc
`essed.
`In the heat exchanger I5 the hydroso1 is
`brought to a temperature which is favorable to
`the setting or gelling action which takes place
`in the zone or chamber I'I.
`If desired, the flow of the hydrosol through
`conduit Iii to the gelling Zone I'I ¿may be effected
`by the pumps 3 and IIB or a third pump I8 may
`be provided in conduit IAi to effect and control
`the iiow of the hydrosol. This pump I8 also may
`be of the metering type so that a predetermined
`quantity of hydrosol may be supplied to the
`gelling or setting zone I‘I within a given time to
`control the flow of hydrosol and hydrogel through
`the zone. Other means of flow control (not
`shown) may be used in place of and in conjunc
`tion with pump I8.
`The gelling or setting zone or chamber com
`prises a vertical tank having a closed upper end
`and an open lower end or base. A valve con
`trolled vent it communicates with the closed
`upper portion of the chamber I'I for discharging
`air or other gas from the chamber I1 when the
`latter is initially filled with hydrosol at the be
`ginning of the process operation. Thereafter the
`vent is maintained closed. The lower end of the
`tank Il is provided with a grid 20 which serves
`to cut the hydrogel discharged from the lower
`end of the gelling or setting zone into elongated
`endless bodies.
`Grid 2@ acts as a cutter through which the set
`hydrogel is extruded as the result of the pres
`sure exerted by the pumps 3, Il) and I8 and the
`force of gravity acting on the mass of hydrosol
`and hydrogel in the gelling Zone I1. As shown,
`the grid 2@ consists of a heavy wire screen or
`intersecting plates with rectangular mesh by
`means of which the gel is cut vertically into rec
`tangular columns, but it may be of different con
`struction.
`In Figures 2 and 3, a modified form of grid 22
`is shown in which the cross section of the open
`ings 23 decrease downwardly, 'I‘he taper of the
`grid segments may be of the order of 2%, and it
`will be appreciated that the taper of the plates
`depicted in Figure 3 is exaggerated. This type
`of grid serves to restrict the extrusion of the gel
`to prevent too rapid movement of the gel in the
`gelling zone. The openings 23 may obviously be
`other than rectangular.
`Referring again to Figure 1, it will be noted
`that immediately below the grid 2U is a horizontal
`cutting »means 2d driven by an actuator 25. The
`cutter actuator 25 may be driven or regulated by
`the flow of either or both the liquid reactants,
`either before or after admixture, towards the
`setting or gelling Zone I 1. The cutting means
`214, which may be a single wire, is designed to
`pass at intervals through the mass of hydrogel
`being extruded through the grid 20, thereby cut
`ting the rectangular shaped columns at right
`angles to the ñrst division into portions of opti
`mum size. If the rate of travel of the cutting
`means 2d is governed by the amount of solution
`entering the setting or gelling vessel I'I, the hy
`drogel will be cut into portions of the same length
`irrespective of the time required to form the hy
`drogel in the setting chamber I'I. Further re
`
`30
`
`35
`
`40
`
`45
`
`75
`
`SNF Exhibit 1025, Page 4 of 7
`
`

`
`2,485,249
`
`6
`the liquid level in tank 36 at a region above the
`grid 20.
`,
`As the hydrogel is extruded through grid 20 and
`out by cutter 24, the small particles are suspended
`in the washing medium in tank 36 and settle
`downwardly through the up-fiowing washing me
`dium to form a bed of hydrogel on the grate 33.
`As shown in Figures 4 and 5, the grate 39 is
`formed of a plurality of ñxed grate bars 45 and
`a plurality of rotatable grate bars 46. The latter
`are provided with gears or sprockets 41 which are
`driven by actuating means (not shown). It will
`be noted that the rotatable bars 4B are provided
`with arms 4S’ extending radially thereof at 90°
`
`10'
`
`15
`
`.
`5
`duction in the size of the brittle gel portions is
`prevented by conducting the cutting operations
`While the gel is immersed in water.
`It is also within the concept of the present in
`vention to effect cutting of the gel mass in the
`setting or gelling chamber l1 transversely there- .
`of prior to extrusion through the grid. An ap
`paratus embodying this feature of the invention
`is shown in Figure 6 in which the setting or gel
`ling chamber is indicated by reference character
`26. This chamber as indicated has a slot 21 in
`the Wall thereof through which a cutting wire
`28 is moved. Wire 23 is carried by an annular
`toothed member 23 supported between rollers 30
`and guided Vby rollers 3l. Toothed member 2S
`is rotated about the chamber 23 being driven
`through a pinion 32 by a motor 33. A housing
`34 encases the toothed member 29 and associated
`mechanism and serves to join together the sec
`tions of the tank severed by the slot 21.
`In operation, the downwardly moving mass of
`gel is severed into a helical body which on extru
`sion through the grid 33 is cut into small bodies,
`which are discharged through the bottom of the
`Vessel 26.
`’ It has been found that by tapering the setting
`or gelling chamber I1 or 26 inwardly, at least at
`its lower portion so that the tank has a taper 0f
`about 5%, any cracks which may form in the Set
`hydrogel as the hydrogel moves downwardly
`through the tank are pushed together or closed.
`This prevents seepage of the hydrosol through the
`set hydrogel in the lower portion of the tank. It
`also retards in cooperation with the grid 2l, the
`movement of the set gel.
`In lieu of tapering the sides of the setting or
`gelling tank to decrease the cross section thereof
`at the lower portion, it is Within the concept of
`this invention to employ a rod or other body posi
`tioned centrally within the tank, which rod or
`body increases in cross section toward the bottom
`of the tank, thus decreasing the effective cross
`section of the tank at the bottom thereof even
`though the tank is truly cylindrical.
`It has been found advantageous to discharge ~‘
`the hydrogel into a liquid bath to avoid further
`reduction of size of the small bodies into which
`the gel is cut. Furthermore, as mentioned in con
`nection with Figure 1, by cutting the hydrogel
`columns under liquid, there is less breakage of
`the small bodies. In View of the foregoing it is
`desirable to have the lower end of the gelling
`chamber l1 or 25 immersed in a liquid bath. As
`illustrated in Figure 1, the chamber I1 extends
`down into the open upper portion of a tank 36
`which also serves as a means for washing the gel
`particles discharged therein to remove the water
`soluble reaction products such as sodium sulphate
`therefrom.
`Wash tank 36 is provided with a tapered bot
`tom 31 which terminates in a discharge conduit
`38, and with a grate 39 upon which a bed of hy
`drogel collects.
`A washing medium, such as plain or acidulated
`water, is introduced into the lower portion of the
`washer through conduit 40 and hows upwardly
`through the bed of hydrogel formed in the washer.
`The washing medium escapes through an over
`flow goose neck 4l which is adjustable to vary
`the level of liquid in tank 36. From the goose neck
`4l the water is discharged into a waste pipe 42
`together with vthe discharge from trap 43 of the
`heater l5 and ñows through the jacket of a heat
`exchanger 44 on'the way to disposal. In'normal
`operation the goose neck is adjusted to maintain
`
`intervals.
`
`Y
`
`Y
`
`Y
`
`,
`
`Y
`
`Alternately, a series of hinged louvers may be
`employed. These louvers should be arranged in
`such a manner that the louvers when closed form
`a substantially continuous plane but when moved
`individually, in sequence, or simultaneously on the
`individual hinge arrangement provided for each
`member, form one or more slots or openings for
`the passage of the gel. Another equivalent may
`consist of a series of bars, elliptical or oval in
`cross section so that the longitudinal axis of each
`bar is horizontal and parallel to the axis of the
`adjoining bar. Each of these bars should be ar
`ranged to allow rotation about a longitudinal axis
`parallel to, but also eccentric with, its central
`longitudinal axis. Such a series of bars could be
`arranged to provide a substantially continuous
`plane for support of the gel bed and by rotation
`of the bars about individual axes provide slots
`for the passage of the gel downward. Other simi
`lar arrangements may be designed to perform
`these functions, as, for instance, a series of spaced
`grates.
`In all of these arrangements, the grate will sup
`port the gel bed which will be in the neighborhood
`of 25 feet in depth, and then permit a selected
`portion of the bed to pass downward through the
`original plane of support. There is little or no
`agglomeration of the gel particles, and in this
`connection it is to be noted that the wash water
`exerts a buoying effect so that the mass does not
`tend to compact or become torn upon rotation of
`the grate. It is also to be noted that the succes
`sive rotation of the grates subjects the entire bed
`of(cid:173)a gel to a continuous, though limited, motion,
`which not only serves to prevent agglomeration
`but also insures a uniform discharge of the washed
`gel.
`Moreover, the supporting grate may be elimi
`nated and the gel bed supported by providing a
`cone or wedge-shaped base for the wash tank.
`Ordinarily, this is undesirable since such an ar
`rangement tends to reduce the equal distribution
`of wash water through the gel bed and the positive
`and regular removal of the washed gel from the
`washer 36.
`'
`As indicated in Figure 1 of the drawings, con
`duit 38 is provided with a pair of gates 43 and 43.
`These gates are so ñtted into the conduit 38 .that
`when moved to a closed position they completely
`shut off the conduit to form a compartment or
`lock 5D intermediate the same. The lock provided
`in the conduit 38 by the pair of gates 48 and 49
`serves to permit the discharge of the washed
`hydrogel from the wash tank 36 in small quanti
`ties without undue loss of the washing medium.
`As illustratedy the conduit 38 is submerged in a
`liquid contained in a well 5l. The lower end of
`the conduit 38 discharges into an elbow 52, the
`inlet end of which is of larger diameter than the
`
`25
`
`70
`
`15
`
`SNF Exhibit 1025, Page 5 of 7
`
`

`
`2,485,249
`
`10
`
`15
`
`20.
`
`25
`
`per .f’
`end of the discharge conduit 38 so as to provide a
`spacing 53 between the exterior wall of the con
`duit 33 and the interior wall of the elbow 52,
`thereby affording communication between the in
`terior of the elbow 52 and the liquid within the
`well 5|. This enables the liquid contained inthe
`well 5| to flow into the elbow 52 after the gate 45
`has been closed and enables the discharge of the
`gel from elbow 52 up through the worm drive
`conveyor 54 onto a conveyor belt 55 by means of
`which the washed hydrogel is conveyed to a region
`out of the liquid contained in the well 5|.
`After a portion of the divided gel has passed
`through the grate 39, it settles against the gate
`48. This gate is periodically opened and admits
`the gel into the compartment 5l). When this
`compartment is full, the gate 48 closes and thel
`gate 49 opens. The gel is then drawn through the
`elbow 52 by the wor-rn conveyor 54 and discharged
`upon the belt 55 by which it is transported for
`further treatment such as drying and activation.
`During this action, washing liquid is free to pass
`through the peripheral slot 53 of elbow 52. The
`gate 59 is then closed and the removal procedure
`repeated.
`The liquid in the well 5| may be the same as
`that used for Washing the gel in wash tank 36.
`In this instance, a washing medium, such as
`water, may be introduced through conduit 56
`into the well 5| to-gether with a supply of acid
`from conduit 51. Valves are provided to regulate
`the proportions of water and acid introduced into
`the well 5|. From the Well 5|, the washing- me
`dium is withdrawn by pump ‘58 and passed
`through the heat exchange unit dd where the
`temperature is raised by reason of the heat eX
`change relation existing between the saine and
`the water passing through the waste conduit d2.
`From the heat exchanger Ml the washing medium(cid:173)
`is introduced through conduit ¿i6 into the lower
`portion of the washer 36 beneath grate 39. If
`desired, the washing medium discharged by the
`pump 58 may be introduced directly into the
`lower portion of the washer 36 without passing
`through the heat exchanger 4M. Steam may be
`introduced with the washing medium through
`the conduit 53, or, if desired, steam may be in
`jected into the bottom of the washer 36 through
`the jet.66 which communicates with the steam
`pipe 516.
`The interior surfaces of the chamber il and
`wash tank 36 are treated to withstand the action
`of sulphuric acid. In practice, the interior sur
`faces of the setting tank I1 can be suiiiciently
`protected by the application of a layer of lead or
`tar or equivalent substance. A tar layer is pref
`erable because it prevents the unset gel from
`wetting and sticking to the surfaces. It will be
`advantageous to have all the interior surfaces of
`the washer 36 made of a material which is re
`sistant to dilute sulphuric acid, and the same
`applies to the well 5| and its associated appa
`ratus, in the event a weak -acid solution is used
`in the well.
`When initiating the process, a layer of molten
`paraiiin, or other material immiscible with water
`and easily congealed and melted, is provided on
`the surface of the wash liquid and the level is
`raised to approximately the upper surface of the
`grid 26. This layer then hardens and ñlls the
`interstices oi the grid to support the hydrosol
`initially introduced into the setting tank |1. To
`effect and maintain solidification of the paraffin,
`a coil 6| is provided in the upper portion of the
`Washer 36 adjacent the grid and is supplied with
`
`8
`cold water through conduit 62. After the hy
`drosol sets to a gel to a substantial depth in the
`setting tank and is suñ‘ìcient to support the body
`of unset hydrosol thereabove, the parafûn is
`melted by injection of steam through jet 63 or
`by passage of steam through the coil 6l previ
`ously used for cooling. Such molten parafün in
`the base of setting tank |‘| is forced out by the
`descending mass of gel, which latter is now free
`to be extruded through the grid 20. The wash
`water may then be adjusted to the normal level
`and the paraffin layer either left upon the body
`of wash water or removed and stored until the
`next time operations have to be initiated. If
`desired, a trough can be placed around the upper
`edge of the wash tank 36, and, to remove the
`paraflin, the level of the wash liquid may merely
`be raised until the molten paraffin overiiows into
`said trough.
`y
`The gelling or setting tank I'I is of a sufûcient
`length and the rate of discharge of the hydrogel
`from the lower portion of the'setting tank is so
`controlled that the passage of the gel-forming
`material through the tank will require a time
`adequate for the setting of the hydrogel. The
`flow of the hydrogel through the gelling zone l1
`is controlled yby the hydraulic pressure on the
`supply of hydrosol to< the upper portion of the
`gelling Zone. Normally this pressure is suliicient
`to accelerate the movement of the gel through
`the zone, but in some instances the amount of
`hydrosol admitted to the top of the tank l1 may
`not be enough to compensate for the movement
`of the gel toward the discharge end under the
`action of gravity, and in this event a suction will
`be established in the top of tank |'| (vent |9
`being closed). Therefore, a low pressure of the
`hydrosol may actually serve to retard the move
`ment of the hydrogel. Consequently, the hy
`draulic pressure of the hydrosol can effect any
`desired rate of movement of the hydrogel through
`the zone.
`By so controlling the rate of discharge and
`having the tank of the proper length, a body of
`set hydrogel will be formed a given distance from
`the bottom of the tank and will slide as a body
`down through the tank. This will serve to sup
`port the hydrosol in the upper portion of the
`setting tank.
`Ordinarily, considerable time is required to
`effect proper washing of a hydrogel such as a
`silica hydrogel formed by the reaction of solu
`tions of sulphuric acid and sodium silicate. In
`order to provide ample time for the washing of
`the gel bodies discharged from the lower end of
`the setting tank |'| into the washer 36, the washer
`is made of a suñicient depth and the rate of dis
`charge of the washed gel from the lower portion
`thereof is so controlled that the gel will be sub
`jected to the action of the washing medium for
`a predetermined required time.
`` It is believed apparent from the above descrip
`tion that a uniform and improved hydrogel can
`be produced by the process and apparatus of the
`present invention with a distinct saving of labor,
`time and materials. Although this invention has
`been described in connection with the production
`of a silica gel, the process and apparatus may be
`readlly adapted to the production of any hydrogel
`by the employment of suitable temperatures and
`by effecting any necessary changes in the size
`and shape of the equipment.
`I claim:
`1. A process of forming a hydrogel within an
`elongated gelling zone having an upper inlet end
`
`35
`
`40
`
`50
`
`60
`
`65
`
`70
`
`75
`
`SNF Exhibit 1025, Page 6 of 7
`
`

`
`9
`and a lower outlet end having a grid associated
`therewith comprising forming a liquid-tight plug
`in the lower end of the gelling zone about said grid
`by cooling and solidifying molten parañîn, sub
`sequently introducing gel-forming material into
`said. ‘zone and maintaining it there under the
`constraint of said liquid-tightplug to form a gel,
`melting the aforementioned plug, and removing
`the gel thus formed.
`2. A process of forming a hydrogel within an
`10
`elongated gelling zone having an upper inlet end
`and a lower outlet end having a grid associated
`therewith comprising depositing a layer of molten
`parafñn on the surface 0f a body of water, rais
`ing the surface of the body of water about the
`lower end of said gelling zone to raise the layer
`of paramn up into the zone about said grid, cool
`ing and solidifying the layer of paraiñn to form
`a plug in the lower end of the gelling zone, sub
`sequently introducing gel-forming material into
`said zone and maintaining it there under the
`constraint of said liquid-tight plug to form a gel,
`melting the aforementioned plug, and removing
`the gel thus formed.
`3. Apparatus for gelling sols and for washing
`and producing a gel product comprising an elon
`gated chamber, an inlet at the top thereof, an
`outlet at the bottom thereof, a second elongated
`chamber of greater cross sectional dimension sur
`rounding said outlet, a washing liquid inlet near
`the bottom of said second elongated chamber, a
`washing liquid outlet near the top of said second
`elongated chamber, and a ventline having a valve
`
`15
`
`20
`
`25
`
`30
`
`2,485,249
`
`10
`therein communicating with the upper end of
`said ñrst named chamber.
`
`HORACE M. WEIR..
`
`REFERENCES CITED
`The following references are of _record in the
`file of this patent:
`UNITED STATES PATENTS
`Number
`Name
`Date
`838,658
`Silvera __________ __ Dec. 18, 1906
`1,088,635
`Stevens __________ __ Feb. 24, 1914
`1,393,383
`Linebarger ________ -_ Oct.`11, 1921
`1,438,048
`Marsh __________ __ Dec. 5, 1922
`1,457,977
`Kitsee ____________ __ June 5, 1923
`1,612,167
`Beardsley et al. ____ Dec. 28, 1926
`1,665,453
`Grunert __ ________ __ Apr. 10, 1928
`1,884,618
`Downard ________ __ Oct. 25, 1932
`2,006,586
`Downard __________ __ July 2, 1935
`2,063,663
`Downard __________ __ Dec. 8, 1936
`2,232,727
`Peterkin et al _____ __ Feb. 25, 1941
`2,284,435
`Lowe et al. ______ __ May 26, 1942
`2,303,340
`Dreyfus __________ __ Dec. 1, 1942
`2,323,583
`Wilson __________ __ July 6, 1943
`2,326,523
`Connolly et al _____ __ Aug. 10, 1943
`2,336,734
`Jellinek __________ __ Dec. 14, 1943
`2,358,202
`Behrman ________ __ Sept. 12, 1944
`2,370,200
`Shadbaker ______ __ Feb. 27, 1945
`FOREIGN PATENTS
`Date
`Country
`Great Britain ____________ __ 1913
`Great Britain ____ __ June 3, 1943
`
`Number
`28,789
`553,736
`
`SNF Exhibit 1025, Page 7 of 7