CA1173308A - Method of producing a tubular filter element having high permeability - Google Patents
Method of producing a tubular filter element having high permeabilityInfo
- Publication number
- CA1173308A CA1173308A CA000187474A CA187474A CA1173308A CA 1173308 A CA1173308 A CA 1173308A CA 000187474 A CA000187474 A CA 000187474A CA 187474 A CA187474 A CA 187474A CA 1173308 A CA1173308 A CA 1173308A
- Authority
- CA
- Canada
- Prior art keywords
- producing
- filter element
- support
- suspension
- element according
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
- B01D71/02—Inorganic material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D39/00—Filtering material for liquid or gaseous fluids
- B01D39/14—Other self-supporting filtering material ; Other filtering material
- B01D39/20—Other self-supporting filtering material ; Other filtering material of inorganic material, e.g. asbestos paper, metallic filtering material of non-woven wires
- B01D39/2068—Other inorganic materials, e.g. ceramics
- B01D39/2072—Other inorganic materials, e.g. ceramics the material being particulate or granular
- B01D39/2075—Other inorganic materials, e.g. ceramics the material being particulate or granular sintered or bonded by inorganic agents
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
- B01D61/14—Ultrafiltration; Microfiltration
- B01D61/145—Ultrafiltration
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
- B01D61/14—Ultrafiltration; Microfiltration
- B01D61/147—Microfiltration
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D63/00—Apparatus in general for separation processes using semi-permeable membranes
- B01D63/06—Tubular membrane modules
Abstract
"METHOD OF PRODUCING A TUBULAR FILTER
ELEMENT HAVING HIGH PERMEABILITY"
ABSTRACT OF THE DISCLOSURE
This invention relates to tubular filter elements formed from at least one thin coating of at least one metallic oxide and/or one metallic fluoride deposited on a ceramic or metallic support.
The invention provides a method of producing such a filter element having both high permeability and very small pores which comprises the steps of bringing the inner and/or the outer wall of the support into contact with a liquid containing in suspension the mineral powder which is required to form the porous coating. The support is then drained and after drying the support is subjected to an isostatic compression and then heat treatment.
'.
ELEMENT HAVING HIGH PERMEABILITY"
ABSTRACT OF THE DISCLOSURE
This invention relates to tubular filter elements formed from at least one thin coating of at least one metallic oxide and/or one metallic fluoride deposited on a ceramic or metallic support.
The invention provides a method of producing such a filter element having both high permeability and very small pores which comprises the steps of bringing the inner and/or the outer wall of the support into contact with a liquid containing in suspension the mineral powder which is required to form the porous coating. The support is then drained and after drying the support is subjected to an isostatic compression and then heat treatment.
'.
Description
3~
This invention relates to Mineral tubular filter elements and more par-ticularly to filters formed from at least one thin coating of at least one metailic oxide and/or at least one metallic fluoride deposited on a , . . . .
ceramic or metallic support~
Accordin~ to a known process, filter elements ... .
; of this kind are generally tubular and are made by moulding ; pulverulent inorganic material and heat treatment to :~`
make the assembly mechanically strong, in accordance with techniques which are now conventional ~n the ceramics and powder metallurgy industries. ~hese elements may be made from various metals and alloys such as steel, bronæe and nickel or from oxides such as alumina, magnesia and silicates, or compounds which are substantially refractory, such as the fluorides, carbides, nitrides and borides.
To produce tubes, these pulverulent materials are mixed with an organic binder and extruded under pressure through an annular no~zle. The tubes are then dried and heat treated to eliminate the binders and ensure cohesion oE the powder particlesO
- This technique is very suitable for the production of relatively thick tubes, for example of a thickness of several millimetres.
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These porous supports or filters, however, must in most cases have a permeability which is as high as possible to permit maximum flow and very srnall pressure ` drop in the fluids passing through them.
; 5 In view of these requirement~, therefore, an attempt has been made to make such tubeswith ~ery small thicknesses, but their industrial production is difficult and complex and these tubes have a very low mechanical strength,. Filter elements are thereore conventionally made with an appreciable flow, i.e. relatively hi~h pore dimensions, i~e. using powders ha~ing coaxse particles~
It is9 however, freqtlently necessary, particularly ~or the separatlon of gaseous isotopes or for checking very fine particles, that the said elements should have a very fine `~ 15 teX-ture with very small pore radii. Such a requirement ~ is not compatible with the requirement of hiqh permeability, `~ which is a prime requirement for the filter ele~ents in .
question.
,.......................................................... .
To produce fiIter elements which satisfy these requirements, it is now con~entional practice to make multi-layer materials, i.e. materials which in respect ; of thickness are formed from a high-permeability layer and large pore radii, and low-permeability layers with ~ery fine pore radii.
.
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,3~8 In actual fact~ and in the most usual cases 9 these filter elements are formed from a high-permeability , .
tubular support providing the mechanical strength of the ,:.
;~ assembly, on which a very thin coating is deposited, . 5 generally inside the tube and which imparts its own '.~ characteristics as to flow and given pore radii. The .
radius of the tubular support pores is usually between 1 and 20 microns~ ' Of course the coating must be as thin as possible in order not to reduce the permeability of the assembly excessively.
Since the inside diameter o* the high-.: permeability support is oftensmall t it is not possible to ~.
deposit the fine coating by spraying a suspended powder, whether electro-statically or otherwise, as is conventional ; 15 practice in painting. Various coating processes have therefore been proposed, for example: spraying dry powder . inside a porous tube previously impregnated with a volatile liquid. Because of the difficulty of feeding a nozzle with a dry powder, this pL-OCeSS results in het~rogeneous 20 deposits of non-uniorm thickness~ said deposits particularly .. belng very fragile. In practi.ce ~t is impossible to : handle these elements after coating without damaging them and this very slow process is not an industrial process.
In another coating method, a suspension.of the mineral powder for deposition in a volatile liquid ~Jhich , ' ' .
.~' ' .
' -..
.. ~ .
~' ', . I
3~8 is inert ~lith respect to said powder is filtered through .
the porou~s supportin~ tube.
.- The thickness of.the coating can be adjusted given an equal suspension concentration, by the filtering time or by measuring the volume of filtered liquid. As a result of turbulence phenomena during filtering, it is not possible with this method to obtain very thin coatings such as are required ~or the production of el.emenets havin~ a high rate of flowO Also~ this process uses heavy and complex equipment and very appreciable quantities of suspension~
, Other methods which are still more complex may be used, fbr example deposition by centrifugation;
- the tube filled with a suspension of the powder in a liquid is r o tated about its axis so that the powder is deposited . on the inner wall of the support; alternatively there is -. coating by b~ushing of a paste formed from the powder .1. and a solvent, and so on. All these techniquesrequire .,~, .. . .
relat~vely complex apparatus which does not readily lend ; . 20 itself to large scale production of composite porous elements and none o these techniques results in the required characteristics, i~eO a very thin deposited coating and an absence of faults in said coating.. The i~ present invention provides considerable improvements in the construction of these separator elements~
... : 5_ ... .. .
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. The invention relates to a met~od o:E producing a tubular filter element ha~ing both high permeability.
and very small pores, from a rigid metal or ceramic support and at least one thin mineral. porous coat.ing, the or each porous coa~ing having pores smaller than those o~ the said support, said method comprislng the steps of bringing the inner and/or outer wall of the support in-to contact , with a liquid containing in suspension a mineral powder which is required to form the porous coa~ing, said liquid ensuring transport of the mineral powder and its adhesion I . to the support, draining the support, drying it.,~compressin~
.`~ it and heating itL The resulting coating may be compressed on its support by ~eans o a resilient diaphragm to compact it and give it greater mechanical strength and, if required, reduce the pore size which is between 0.001 and 1 micron.
It may also be heat-treated so as to be mechanically ~; consolidated~ The suspension of mineral powder in a liquid adapted to ensure deposition on the porous suppo.rt ~ay contain a small proportion of one or more orgaI~ic products which can act as a temporary binder to ensure coheslon of the particles of mineral powder after elimina-tion of the liquid, or as an agent to facilitate dispersion or defloculation o said mineral powder or alternatively - which can favourably modify the rheological characteristics of the suspension.
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In this wa~ the nature, concentration of the organic binder used~ and the pH of the suspension determine the viscosity o said suspension and its yield value~
which have a great influence on the regulation of the thick~ess of -the deposit and on the homogeneity of the latter along the support. Using suspensions having a Ne~nian flow, during draining o-~ the liquid the top part of the support is stripped while the base is loaded ?
and this results in appreciable heterogeneity of the deposit~ By selecting the constituents of the suspension and, in particular~ the organic binder so that it has a yield value or minimum stren~th point, the deposit can on the other hand be perfec~ly homogeneous~ In this connection see "Ceramique Génerale - Notions de Physico-Chimie", Vol~ II, pa~es 137 to 144, by C. A. Jouenne~
According to one simple process, the filter elements according to the invention may be constructed .
by filling the support or supports with the suspension, by leaving them in contact therewith for a given time, emptying out the suspension and allowing the element coated in this way to drain and dryO This filter is then subjected to a heat treatment adapted to eliminate the organic binder or binders or volatile or chemical . . . .
products and consolidate the deposited mineral film.
The invention also relates to apparatus for . performing the method according to the invention9 said ... . .
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apparatus comprising a closed container formed with an orifice f~or the supply of mineral powder suspension, a venting conduit and a conduit for connecting the interlor of the container to pressure, a supportinq tube imrnersed 5 to near the bottom of the container and adapted to support the tubular element, and a control unit for the level of the suspension at a tube surmounting the tubular element.
According to a specific embodiment of this apparatus, the ends o the tubular elements are provided 10 with sealing-tight gasketsg the top part comrnunicating with atube which, as a result of its transparency, allows the suspension level to be monitored, and which is el-~tr.'c~l provided with a photoelectric cell or~probe system which . ensures that coating stops when the level of the suspension 15 reaches said transparent part~ The bo-ttom end of each tu~ular element communicates with a supporting tube immersed in. he.suspension in a sealed tank to which excess ~ir pressure is appliedO This excess pressure . causes the suspension to rise in the support and results 20 in its coating~
One embodiment of the apparatus will now be . ~ described by way.of example of the invention with reference . to the accornpanying ~awlngs, in which the single figure . is a.sectional ~iew of said apparatus~
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A tubular filter element 1, the ends of ~Jhich are provided with two sealing-tight gaskets 2 and 3, ls kept in communication with a glass tube 4 at the top and with a metal supporting tube 5 at the bottom, the tube 5 . 5 being connected to a tank 6. The latter is provided with .-~. a T-tube 7, the limbs.of which are provided with a valve 8 and a val~e 9 which r.especti~ely allow the ad~ission o~ a compressed gas and connection to atmospheric pressureg The supp~ting tube 3 is immersed al~ost to ~0 the bottom of the tank which is filled with liquid .: suspension 10, fillin~ being via the sealed orifice 11 ~ The suspension level is mon.itored by the photoelectric - cell 12, its receiver 13 and a control unit 14. Coating is effected by placing the filter element 1 between the : 15 tu~es ~ and 5, closing the atmospheric pressure venting :;. valve 9 and opening the pressure gas admission valve 8.
., j .
. This pressure, which is applied to the liquid suspension 10, ~: causes the latter to rise in the supporting tube. When ` ~ the suspension level reaches the detection zone of the photoelectric cell 12 and 13, the latter closes the ,: . valve 8 and opens the valve 9 via the control unit 14.
.~ The suspen~ion falls back into the tank 6. After .~ d~aining, the support is disconnected from the machine and : .. . .
`~: the operation can be re-commenced with a new support.
.; . 25 Of course, instead of using a pressure on the . ~ .
~.~ liquid suspension, a negative pressure could be produced ~,.. . .
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via the tube 4 so as to cause the suspension to rise in the same way ln the support9 and this adaptation is within the scope of the invention~
The invention is illustrated with the aid of the following examples, which are given by way of example only.
Exam~le 1: A tubular refractory ceramic support having an outside diameter o-E 20 mm, a thickness of 2 mm, a length of 500 mm and pores having radii of 5 microns, ~s filled with the suspension prepared as below:-300g of electrically melted alumina powder having a grain size very close to 5 microns, are suspended in a well-homogenised solution of:
15g of carboY~ymethyl cellulose lS 30g o glycerine 500cc of ethyl alcohol ... .
;~ 500cc of water~
This suspension is introduced into the support ~; ~ by means of the apparatus as described. After draining and drying at ambient temperature and then in an oven the element obtained in this way is provided with two inner , and outer polymer diaphragms and subjected to an isostatic compression of 1500 bars in a water-filled press pot~
.
The ob;ect of this compression is to make the deposited layer very compact and anchor said layer in the support, : ', ' ' .
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After this operation the layer is subjected to heat treatment at 1800C ~or one hour. The resulting filter has a very high permeability and the radius of the pores of the deposited layer or coating is 1 micron~
Example 2: A tubular support identical to that in Example 1 is coated by means of the following suspension:
300q of a calcined alumina powder of a grain siz~
between 1 and 15 microns and a specific s~rface of 8m per gram are added to X litre of an aqueous gel containing 0.2% of ethyl methyl cellulose. The suspension is agitated and then left for two days , and finally screened on a 40 micron cloth. The - coating vbtained has a thickness of 20 microns and ` ~ is compressed, as in Example 1, between two diaphragms - 15 at a pressure of 800 bars. After heat treatment in . .
air at 1500c,~the resulting element has pores of a ;;` radius of 0.~ micron on average~
~ ~ : A sintered nickel tube having an outside ~ ,.
` ~ diameter of 15 mm, a thickness of 0.5 mm and a length of 500 mm is coated with a suspension formed rom the ~"' follol,Jing:
, . .
;'~ 250g of calcium fluoride of a grain size of the order of 3 microns
This invention relates to Mineral tubular filter elements and more par-ticularly to filters formed from at least one thin coating of at least one metailic oxide and/or at least one metallic fluoride deposited on a , . . . .
ceramic or metallic support~
Accordin~ to a known process, filter elements ... .
; of this kind are generally tubular and are made by moulding ; pulverulent inorganic material and heat treatment to :~`
make the assembly mechanically strong, in accordance with techniques which are now conventional ~n the ceramics and powder metallurgy industries. ~hese elements may be made from various metals and alloys such as steel, bronæe and nickel or from oxides such as alumina, magnesia and silicates, or compounds which are substantially refractory, such as the fluorides, carbides, nitrides and borides.
To produce tubes, these pulverulent materials are mixed with an organic binder and extruded under pressure through an annular no~zle. The tubes are then dried and heat treated to eliminate the binders and ensure cohesion oE the powder particlesO
- This technique is very suitable for the production of relatively thick tubes, for example of a thickness of several millimetres.
. -- . .
; ' - ~
'~ .
~ 3~3~
These porous supports or filters, however, must in most cases have a permeability which is as high as possible to permit maximum flow and very srnall pressure ` drop in the fluids passing through them.
; 5 In view of these requirement~, therefore, an attempt has been made to make such tubeswith ~ery small thicknesses, but their industrial production is difficult and complex and these tubes have a very low mechanical strength,. Filter elements are thereore conventionally made with an appreciable flow, i.e. relatively hi~h pore dimensions, i~e. using powders ha~ing coaxse particles~
It is9 however, freqtlently necessary, particularly ~or the separatlon of gaseous isotopes or for checking very fine particles, that the said elements should have a very fine `~ 15 teX-ture with very small pore radii. Such a requirement ~ is not compatible with the requirement of hiqh permeability, `~ which is a prime requirement for the filter ele~ents in .
question.
,.......................................................... .
To produce fiIter elements which satisfy these requirements, it is now con~entional practice to make multi-layer materials, i.e. materials which in respect ; of thickness are formed from a high-permeability layer and large pore radii, and low-permeability layers with ~ery fine pore radii.
.
~ --3 ; , . .
.:
... .
. . ' ' , ~ .
:', .
.. ;- .
,3~8 In actual fact~ and in the most usual cases 9 these filter elements are formed from a high-permeability , .
tubular support providing the mechanical strength of the ,:.
;~ assembly, on which a very thin coating is deposited, . 5 generally inside the tube and which imparts its own '.~ characteristics as to flow and given pore radii. The .
radius of the tubular support pores is usually between 1 and 20 microns~ ' Of course the coating must be as thin as possible in order not to reduce the permeability of the assembly excessively.
Since the inside diameter o* the high-.: permeability support is oftensmall t it is not possible to ~.
deposit the fine coating by spraying a suspended powder, whether electro-statically or otherwise, as is conventional ; 15 practice in painting. Various coating processes have therefore been proposed, for example: spraying dry powder . inside a porous tube previously impregnated with a volatile liquid. Because of the difficulty of feeding a nozzle with a dry powder, this pL-OCeSS results in het~rogeneous 20 deposits of non-uniorm thickness~ said deposits particularly .. belng very fragile. In practi.ce ~t is impossible to : handle these elements after coating without damaging them and this very slow process is not an industrial process.
In another coating method, a suspension.of the mineral powder for deposition in a volatile liquid ~Jhich , ' ' .
.~' ' .
' -..
.. ~ .
~' ', . I
3~8 is inert ~lith respect to said powder is filtered through .
the porou~s supportin~ tube.
.- The thickness of.the coating can be adjusted given an equal suspension concentration, by the filtering time or by measuring the volume of filtered liquid. As a result of turbulence phenomena during filtering, it is not possible with this method to obtain very thin coatings such as are required ~or the production of el.emenets havin~ a high rate of flowO Also~ this process uses heavy and complex equipment and very appreciable quantities of suspension~
, Other methods which are still more complex may be used, fbr example deposition by centrifugation;
- the tube filled with a suspension of the powder in a liquid is r o tated about its axis so that the powder is deposited . on the inner wall of the support; alternatively there is -. coating by b~ushing of a paste formed from the powder .1. and a solvent, and so on. All these techniquesrequire .,~, .. . .
relat~vely complex apparatus which does not readily lend ; . 20 itself to large scale production of composite porous elements and none o these techniques results in the required characteristics, i~eO a very thin deposited coating and an absence of faults in said coating.. The i~ present invention provides considerable improvements in the construction of these separator elements~
... : 5_ ... .. .
.
~ ~ .
, .. ,. ,~,. . .
...... .
... .
... . .
.;. .
~ 3 ~'`'"
. The invention relates to a met~od o:E producing a tubular filter element ha~ing both high permeability.
and very small pores, from a rigid metal or ceramic support and at least one thin mineral. porous coat.ing, the or each porous coa~ing having pores smaller than those o~ the said support, said method comprislng the steps of bringing the inner and/or outer wall of the support in-to contact , with a liquid containing in suspension a mineral powder which is required to form the porous coa~ing, said liquid ensuring transport of the mineral powder and its adhesion I . to the support, draining the support, drying it.,~compressin~
.`~ it and heating itL The resulting coating may be compressed on its support by ~eans o a resilient diaphragm to compact it and give it greater mechanical strength and, if required, reduce the pore size which is between 0.001 and 1 micron.
It may also be heat-treated so as to be mechanically ~; consolidated~ The suspension of mineral powder in a liquid adapted to ensure deposition on the porous suppo.rt ~ay contain a small proportion of one or more orgaI~ic products which can act as a temporary binder to ensure coheslon of the particles of mineral powder after elimina-tion of the liquid, or as an agent to facilitate dispersion or defloculation o said mineral powder or alternatively - which can favourably modify the rheological characteristics of the suspension.
. . .
.' ' .
~ -6- ~
... . . .
. ,:
, ",~, , . .
3~)~
In this wa~ the nature, concentration of the organic binder used~ and the pH of the suspension determine the viscosity o said suspension and its yield value~
which have a great influence on the regulation of the thick~ess of -the deposit and on the homogeneity of the latter along the support. Using suspensions having a Ne~nian flow, during draining o-~ the liquid the top part of the support is stripped while the base is loaded ?
and this results in appreciable heterogeneity of the deposit~ By selecting the constituents of the suspension and, in particular~ the organic binder so that it has a yield value or minimum stren~th point, the deposit can on the other hand be perfec~ly homogeneous~ In this connection see "Ceramique Génerale - Notions de Physico-Chimie", Vol~ II, pa~es 137 to 144, by C. A. Jouenne~
According to one simple process, the filter elements according to the invention may be constructed .
by filling the support or supports with the suspension, by leaving them in contact therewith for a given time, emptying out the suspension and allowing the element coated in this way to drain and dryO This filter is then subjected to a heat treatment adapted to eliminate the organic binder or binders or volatile or chemical . . . .
products and consolidate the deposited mineral film.
The invention also relates to apparatus for . performing the method according to the invention9 said ... . .
. ~ -7_ .
. .
'.` ., ' '~ . .
-^ i .
~;
., .
33~)~
apparatus comprising a closed container formed with an orifice f~or the supply of mineral powder suspension, a venting conduit and a conduit for connecting the interlor of the container to pressure, a supportinq tube imrnersed 5 to near the bottom of the container and adapted to support the tubular element, and a control unit for the level of the suspension at a tube surmounting the tubular element.
According to a specific embodiment of this apparatus, the ends o the tubular elements are provided 10 with sealing-tight gasketsg the top part comrnunicating with atube which, as a result of its transparency, allows the suspension level to be monitored, and which is el-~tr.'c~l provided with a photoelectric cell or~probe system which . ensures that coating stops when the level of the suspension 15 reaches said transparent part~ The bo-ttom end of each tu~ular element communicates with a supporting tube immersed in. he.suspension in a sealed tank to which excess ~ir pressure is appliedO This excess pressure . causes the suspension to rise in the support and results 20 in its coating~
One embodiment of the apparatus will now be . ~ described by way.of example of the invention with reference . to the accornpanying ~awlngs, in which the single figure . is a.sectional ~iew of said apparatus~
. . . . .
. "~
, -8-", .
. ~, .
-' ,.i~, . . .
:`:
, ,~ ' .
.`.: ' ... .
33~
A tubular filter element 1, the ends of ~Jhich are provided with two sealing-tight gaskets 2 and 3, ls kept in communication with a glass tube 4 at the top and with a metal supporting tube 5 at the bottom, the tube 5 . 5 being connected to a tank 6. The latter is provided with .-~. a T-tube 7, the limbs.of which are provided with a valve 8 and a val~e 9 which r.especti~ely allow the ad~ission o~ a compressed gas and connection to atmospheric pressureg The supp~ting tube 3 is immersed al~ost to ~0 the bottom of the tank which is filled with liquid .: suspension 10, fillin~ being via the sealed orifice 11 ~ The suspension level is mon.itored by the photoelectric - cell 12, its receiver 13 and a control unit 14. Coating is effected by placing the filter element 1 between the : 15 tu~es ~ and 5, closing the atmospheric pressure venting :;. valve 9 and opening the pressure gas admission valve 8.
., j .
. This pressure, which is applied to the liquid suspension 10, ~: causes the latter to rise in the supporting tube. When ` ~ the suspension level reaches the detection zone of the photoelectric cell 12 and 13, the latter closes the ,: . valve 8 and opens the valve 9 via the control unit 14.
.~ The suspen~ion falls back into the tank 6. After .~ d~aining, the support is disconnected from the machine and : .. . .
`~: the operation can be re-commenced with a new support.
.; . 25 Of course, instead of using a pressure on the . ~ .
~.~ liquid suspension, a negative pressure could be produced ~,.. . .
_g_ , ' ' ' ' ' , ' ... . .
.~ . . .
~' ~
. .
.: .
. . .
33~
via the tube 4 so as to cause the suspension to rise in the same way ln the support9 and this adaptation is within the scope of the invention~
The invention is illustrated with the aid of the following examples, which are given by way of example only.
Exam~le 1: A tubular refractory ceramic support having an outside diameter o-E 20 mm, a thickness of 2 mm, a length of 500 mm and pores having radii of 5 microns, ~s filled with the suspension prepared as below:-300g of electrically melted alumina powder having a grain size very close to 5 microns, are suspended in a well-homogenised solution of:
15g of carboY~ymethyl cellulose lS 30g o glycerine 500cc of ethyl alcohol ... .
;~ 500cc of water~
This suspension is introduced into the support ~; ~ by means of the apparatus as described. After draining and drying at ambient temperature and then in an oven the element obtained in this way is provided with two inner , and outer polymer diaphragms and subjected to an isostatic compression of 1500 bars in a water-filled press pot~
.
The ob;ect of this compression is to make the deposited layer very compact and anchor said layer in the support, : ', ' ' .
:, ' .
: . ~
. ~ ' '' . ' ` `~ ~
` .
~ ~t7~
After this operation the layer is subjected to heat treatment at 1800C ~or one hour. The resulting filter has a very high permeability and the radius of the pores of the deposited layer or coating is 1 micron~
Example 2: A tubular support identical to that in Example 1 is coated by means of the following suspension:
300q of a calcined alumina powder of a grain siz~
between 1 and 15 microns and a specific s~rface of 8m per gram are added to X litre of an aqueous gel containing 0.2% of ethyl methyl cellulose. The suspension is agitated and then left for two days , and finally screened on a 40 micron cloth. The - coating vbtained has a thickness of 20 microns and ` ~ is compressed, as in Example 1, between two diaphragms - 15 at a pressure of 800 bars. After heat treatment in . .
air at 1500c,~the resulting element has pores of a ;;` radius of 0.~ micron on average~
~ ~ : A sintered nickel tube having an outside ~ ,.
` ~ diameter of 15 mm, a thickness of 0.5 mm and a length of 500 mm is coated with a suspension formed rom the ~"' follol,Jing:
, . .
;'~ 250g of calcium fluoride of a grain size of the order of 3 microns
2 g of polyvinyl aicohol ~ 25 1 litre of water.
,''~.'~ , ,,, ' -11-:.. ' . , ' ' ` ~ .
;- .
1~'7~33~?~3 A-Eter deposition, dryin~, comp~resion at 500 bars and heat treatment at 550C, the resulting element has a ~ery high permeability and a pore radius of approximately 0O3 microns~
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1~'7~33~?~3 A-Eter deposition, dryin~, comp~resion at 500 bars and heat treatment at 550C, the resulting element has a ~ery high permeability and a pore radius of approximately 0O3 microns~
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Claims (13)
1. A method of producing a tubular filter element having both high permeability and very small pores, from a rigid metal or ceramic support and at least one thin mineral porous coating, the or each porous coating having pores smaller than those of the said support, said method comprising the steps of bringing the inner and/or outer wall of the support into contact with a liquid con-taining in suspension a mineral powder which is required to form the porous coating, said liquid ensuring transport of the mineral powder and its adhesion to the support draining the support, drying it, compressing it and heating it.
2. A method of producing a filter element according to claim 1, characterised in that the mineral powder suspension contains a small proportion of an organic binder adapted to modify the rheological properties of the suspension so as to ensure good mechanical solidity of the thin coating after drying and good adhesion of the thin coating on the said support.
3. A method of producing a filter element according to claim 2, characterised in that the organic binder is a cellulose ester.
4. A method of producing a filter element according to claim 2, characterized in that the organic binder is polyvinyl alcohol.
5. A method of producing a filter element according to claim 1, characterised in that a mineral porous coating is formed from at least one metallic oxide.
6. A method of producing a filter element according to claim 1, characterised in that a mineral porous coating is formed from at least one metallic fluoride.
7. A method of producing a filter element according to claim 1, characterised in that the radius of the pores of the filter coating is between 0.001 and 1 micron.
8. A method of producing a filter element according to claim 1, characterised in that the radius of the pores of the sup-port is between 1 and 20 microns.
9. A method of producing a filter element according to claim 1, characterised in that the deposited and dried coating is compressed isostatically by means of two diaphragms disposed on the inner and outer walls of the element, the assembly being dis-posed in a liquid-filled press pot and subjected to a pressure of between 500 and 3,000 bars.
10. A method of producing a filter element according to claim 9, characterised in that heating is carried out between 500 and 1800°C for about one hour.
11. An apparatus for producing a tubular filter element having high permeability and very small pores, said apparatus com-prising a closed container formed with an orifice for the supply of mineral powder suspension, a venting conduit and a conduit for connecting the interior of the container to pressure, a supporting tube immersed to near the bottom of the container and adapted to support the tubular element, and a control unit for the level of the powder suspension at a tube surmounting the tubular element.
12. An apparatus according to claim 11, characterised in that the suspension level control unit comprises an electrical pro-be and a control unit which controls the venting and pressurizing of the interior of the container.
13. An apparatus according to claim 11, characterised in that the suspension level control system comprises a photo-electric cell, a receiver and a control unit which controls the venting and pressurizing of the interior of the container.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR7300494 | 1973-01-08 | ||
| FR7300494A FR2527092B1 (en) | 1973-01-08 | 1973-01-08 | PROCESS FOR THE PREPARATION OF HIGH-PERMEABILITY FILTER ELEMENTS |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1173308A true CA1173308A (en) | 1984-08-28 |
Family
ID=9112986
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000187474A Expired CA1173308A (en) | 1973-01-08 | 1973-12-06 | Method of producing a tubular filter element having high permeability |
Country Status (6)
| Country | Link |
|---|---|
| BE (1) | BE807638A (en) |
| CA (1) | CA1173308A (en) |
| DE (1) | DE2359505C1 (en) |
| FR (1) | FR2527092B1 (en) |
| GB (1) | GB1605214A (en) |
| IT (1) | IT1062795B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5364586A (en) * | 1993-08-17 | 1994-11-15 | Ultram International L.L.C. | Process for the production of porous membranes |
| US6524421B1 (en) * | 2000-09-22 | 2003-02-25 | Praxair Technology, Inc. | Cold isopressing method |
Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2575459B1 (en) * | 1984-12-28 | 1991-10-04 | Commissariat Energie Atomique | PROCESS FOR THE MANUFACTURE OF POROUS AND PERMEABLE MINERAL MEMBRANES |
| JPS61238315A (en) * | 1985-04-12 | 1986-10-23 | Ngk Insulators Ltd | Preparation of double-layered filter |
| JPH0634956B2 (en) * | 1987-08-06 | 1994-05-11 | セントラル硝子株式会社 | Thin film coating method and apparatus |
| NL8702759A (en) * | 1987-11-19 | 1989-06-16 | Hoogovens Groep Bv | METHOD FOR MANUFACTURING A MICRO-PERMEABLE MEMBRANE AND APPARATUS FOR APPLYING THIS MEMBRANE TO A CARRIER |
| GB8812217D0 (en) * | 1988-05-24 | 1988-06-29 | Alcan Int Ltd | Composite membranes |
| DE3840137C1 (en) * | 1988-11-29 | 1990-03-29 | Feldmuehle Ag, 4000 Duesseldorf, De | |
| EP0537929B1 (en) * | 1991-10-07 | 1995-08-16 | Texaco Development Corporation | Membrane and method of separation |
| DE4328295C2 (en) * | 1993-08-23 | 1998-03-26 | Hermann Johannes Pro Schloemer | Method for producing a ceramic sieve filter and sieve filter produced according to this method |
| DE19503703A1 (en) * | 1994-02-07 | 1995-08-10 | Cerasiv Gmbh | Ultrafiltration membrane prodn. |
| US6180168B1 (en) * | 1999-02-01 | 2001-01-30 | Air Products And Chemicals, Inc. | Process for the manufacture of a membrane device with internal sweep |
| DE10123199B4 (en) * | 2001-05-12 | 2005-02-24 | Gkn Sinter Metals Gmbh | Process for producing at least partially internally coated tubular bodies with a coating of a sinterable material |
| CN104475307B (en) * | 2014-11-10 | 2016-09-14 | 华玉叶 | A kind of Mechanical Method spray membrane process |
Family Cites Families (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR949280A (en) * | 1940-03-27 | 1949-08-25 | Gen Motors Corp | Manufacturing process for porous metal parts and resulting products |
| US2392229A (en) * | 1943-01-26 | 1946-01-01 | Wheelco Instr Company | Control apparatus for coating machines |
| US2449783A (en) * | 1943-09-30 | 1948-09-21 | Westinghouse Electric Corp | Apparatus for coating the inside surfaces of tubular vitreous envelopes |
| GB832317A (en) * | 1957-04-05 | 1960-04-06 | Degussa | Process for the production of fine-pore metal filters, membranes and diaphragms |
| NL126633C (en) * | 1958-02-24 | 1900-01-01 | ||
| FR1238354A (en) * | 1959-06-30 | 1960-08-12 | Commissariat Energie Atomique | Process for manufacturing porous elements by sintering metal powders, and porous elements obtained by this process |
| BE625893A (en) * | 1961-03-27 | |||
| US3331772A (en) * | 1965-08-03 | 1967-07-18 | Atlantic Refining Co | Desalting water by reverse osmosis through novel semipermeable membranes |
| BE756838A (en) * | 1969-10-03 | 1971-03-01 | Commissariat Energie Atomique | MONOBLOC HOMOGENEOUS POROUS ALUMINA FILTER ( |
| GB1265132A (en) * | 1970-01-14 | 1972-03-01 | ||
| BE787964A (en) * | 1971-08-24 | 1973-02-26 | Montedison Spa | PROCESS FOR PREPARING POROUS COMPOSITE MEMBRANES OR BARRIERS FOR GAS DIFFUSION SYSTEMS |
-
1973
- 1973-01-08 FR FR7300494A patent/FR2527092B1/en not_active Expired
- 1973-11-19 GB GB53533/73A patent/GB1605214A/en not_active Expired
- 1973-11-22 BE BE0/138018A patent/BE807638A/en not_active IP Right Cessation
- 1973-11-29 DE DE2359505A patent/DE2359505C1/en not_active Expired
- 1973-11-29 IT IT70498/73A patent/IT1062795B/en active
- 1973-12-06 CA CA000187474A patent/CA1173308A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5364586A (en) * | 1993-08-17 | 1994-11-15 | Ultram International L.L.C. | Process for the production of porous membranes |
| US6524421B1 (en) * | 2000-09-22 | 2003-02-25 | Praxair Technology, Inc. | Cold isopressing method |
Also Published As
| Publication number | Publication date |
|---|---|
| FR2527092A1 (en) | 1983-11-25 |
| DE2359505C1 (en) | 1985-12-05 |
| BE807638A (en) | 1983-07-15 |
| GB1605214A (en) | 1984-08-30 |
| FR2527092B1 (en) | 1985-10-25 |
| IT1062795B (en) | 1985-01-31 |
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