CA1324089C - Filtration apparatus - Google Patents
Filtration apparatusInfo
- Publication number
- CA1324089C CA1324089C CA000529802A CA529802A CA1324089C CA 1324089 C CA1324089 C CA 1324089C CA 000529802 A CA000529802 A CA 000529802A CA 529802 A CA529802 A CA 529802A CA 1324089 C CA1324089 C CA 1324089C
- Authority
- CA
- Canada
- Prior art keywords
- liquid
- filter element
- housing
- filtration apparatus
- filtered
- 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 - Fee Related
Links
- 238000001914 filtration Methods 0.000 title claims abstract description 112
- 239000007788 liquid Substances 0.000 claims abstract description 105
- 239000000706 filtrate Substances 0.000 claims description 27
- 238000007599 discharging Methods 0.000 claims description 15
- 239000006194 liquid suspension Substances 0.000 claims description 14
- 238000010926 purge Methods 0.000 claims description 14
- 239000000463 material Substances 0.000 claims description 13
- 239000000203 mixture Substances 0.000 abstract description 10
- 230000007547 defect Effects 0.000 abstract description 3
- 239000000725 suspension Substances 0.000 abstract description 2
- 239000007789 gas Substances 0.000 description 46
- 235000013405 beer Nutrition 0.000 description 16
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 14
- 238000000034 method Methods 0.000 description 13
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 12
- 230000015572 biosynthetic process Effects 0.000 description 11
- 235000006468 Thea sinensis Nutrition 0.000 description 7
- 235000020333 oolong tea Nutrition 0.000 description 7
- 239000001569 carbon dioxide Substances 0.000 description 6
- 229910002092 carbon dioxide Inorganic materials 0.000 description 6
- 239000005909 Kieselgur Substances 0.000 description 5
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 240000004808 Saccharomyces cerevisiae Species 0.000 description 3
- 239000012298 atmosphere Substances 0.000 description 3
- 238000010790 dilution Methods 0.000 description 3
- 239000012895 dilution Substances 0.000 description 3
- 235000020374 simple syrup Nutrition 0.000 description 3
- 238000004804 winding Methods 0.000 description 3
- 241000894006 Bacteria Species 0.000 description 2
- 229910010293 ceramic material Inorganic materials 0.000 description 2
- 230000000875 corresponding effect Effects 0.000 description 2
- 239000006185 dispersion Substances 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 238000004064 recycling Methods 0.000 description 2
- 239000002002 slurry Substances 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 239000004278 EU approved seasoning Substances 0.000 description 1
- 244000182691 Echinochloa frumentacea Species 0.000 description 1
- 235000008247 Echinochloa frumentacea Nutrition 0.000 description 1
- 235000013334 alcoholic beverage Nutrition 0.000 description 1
- 230000003466 anti-cipated effect Effects 0.000 description 1
- 235000013361 beverage Nutrition 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000009960 carding Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 239000008162 cooking oil Substances 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 235000011194 food seasoning agent Nutrition 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000011169 microbiological contamination Methods 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 235000019362 perlite Nutrition 0.000 description 1
- 239000010451 perlite Substances 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 239000002195 soluble material Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 235000013555 soy sauce Nutrition 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 235000000346 sugar Nutrition 0.000 description 1
- 235000021419 vinegar Nutrition 0.000 description 1
- 239000000052 vinegar Substances 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D37/00—Processes of filtration
- B01D37/02—Precoating the filter medium; Addition of filter aids to the liquid being filtered
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D29/00—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
- B01D29/11—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor with bag, cage, hose, tube, sleeve or like filtering elements
- B01D29/114—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor with bag, cage, hose, tube, sleeve or like filtering elements arranged for inward flow filtration
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D29/00—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
- B01D29/44—Edge filtering elements, i.e. using contiguous impervious surfaces
- B01D29/48—Edge filtering elements, i.e. using contiguous impervious surfaces of spirally or helically wound bodies
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D29/00—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
- B01D29/50—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor with multiple filtering elements, characterised by their mutual disposition
- B01D29/52—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor with multiple filtering elements, characterised by their mutual disposition in parallel connection
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D29/00—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
- B01D29/76—Handling the filter cake in the filter for purposes other than for regenerating
- B01D29/80—Handling the filter cake in the filter for purposes other than for regenerating for drying
- B01D29/84—Handling the filter cake in the filter for purposes other than for regenerating for drying by gases or by heating
- B01D29/843—Handling the filter cake in the filter for purposes other than for regenerating for drying by gases or by heating by direct contact with a fluid
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D35/00—Filtering devices having features not specifically covered by groups B01D24/00 - B01D33/00, or for applications not specifically covered by groups B01D24/00 - B01D33/00; Auxiliary devices for filtration; Filter housing constructions
- B01D35/16—Cleaning-out devices, e.g. for removing the cake from the filter casing or for evacuating the last remnants of liquid
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D36/00—Filter circuits or combinations of filters with other separating devices
- B01D36/001—Filters in combination with devices for the removal of gas, air purge systems
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2201/00—Details relating to filtering apparatus
- B01D2201/04—Supports for the filtering elements
- B01D2201/0469—Filter tubes connected to collector tubes
- B01D2201/0476—Filter tubes connected to collector tubes mounted substantially vertically on collector tubes at the lower side of the filter elements
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2201/00—Details relating to filtering apparatus
- B01D2201/04—Supports for the filtering elements
- B01D2201/0469—Filter tubes connected to collector tubes
- B01D2201/0484—Filter tubes connected to collector tubes suspended from collector tubes at the upper side of the filter elements
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2201/00—Details relating to filtering apparatus
- B01D2201/04—Supports for the filtering elements
- B01D2201/0469—Filter tubes connected to collector tubes
- B01D2201/0492—Filter tubes connected to collector tubes positioned between at least two collector tubes
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Filtering Materials (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
The filtration apparatus of the invention is of the type having one or more of upright tubular filter elements with the surface coated with a pre-coat layer of a filter aid through which a liquid is filtered. Different from conventional apparatuses, the filter element in the inventive apparatus is provided with a gas exhaust tube or liquid drain tube connected to the upper or lower part of the element. By virtue of this means, the liquid used for forming the pre-coat layer as the suspension medium can be completely discharged out of the apparatus prior to intro-duction of the liquid to be filtered so that the liquid in the apparatus can be switched from the pre-coat forming liquid to the filtered liquid without producing a mixture thereof causing no defects in the pre-coat layer.
The filtration apparatus of the invention is of the type having one or more of upright tubular filter elements with the surface coated with a pre-coat layer of a filter aid through which a liquid is filtered. Different from conventional apparatuses, the filter element in the inventive apparatus is provided with a gas exhaust tube or liquid drain tube connected to the upper or lower part of the element. By virtue of this means, the liquid used for forming the pre-coat layer as the suspension medium can be completely discharged out of the apparatus prior to intro-duction of the liquid to be filtered so that the liquid in the apparatus can be switched from the pre-coat forming liquid to the filtered liquid without producing a mixture thereof causing no defects in the pre-coat layer.
Description
1~2~:89 ., -. A FILTRATION APPARATUS
BACKGROUND OF THE INVENTION
The present invention relates to a filtration apparatus or, more particularly, to an improvement of a filtration apparatus in which a so-called pre-coat layer of a filter aid is formed on the surface of a filter element or filter ' r~ medium and the liquid is filtered through the thus formed ,, .~
pre-coat layer. Filtration apparatuses of this type are widely used in the manufacturing process of alcoholic drinks such as beer, wine, Japanese sake and the like, seasonings such as soy sauce, vinegar, sugar, cooking oil and the like, other beverages such as f~uit-based drinks, carbonated ¦~ drinks, mineral water, Oolong tea and the like, phanmaceuticals and so on.
` ~. As is known, a type of filtration procedures utilizes apre-coat layer which is formed of a filter aid such as -~ diatomaceous earth, perlite, cellulosic powder, active ~ carbon and the like on the surface of filter elements in a -i ~ substantial thickness and through which the liquid is `~ filtered.
~ 20 The most conventional material as the filter element, ,,.~ , :
~ ~ on which the pre-coat layer is formed, includes filter cloth, ., ~;, , ~ filter net, filtèr paper and the like although several more ~ .. ::
rigid materials are sometimes used including punched metal ,~
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1 tubes spirally wound with a wire, corrugated rectangular tubes (or tubes having an undulate polygonal cross section) spirally wound with a wire, ceramic-made cylindrical elements and so on. Different types of the filter elements may be 5 used either alone or as a combination of two types or more.
Various types of filtration apparatuses utilize one or more of cylindrical or polygonally tubular filter elements provided with a pre-coat layer in an upright disposition.
s These filtration apparatuses are classified into two classes 10 depending on the position at which the filtrate is taken out ~ of the filter element. Namely, the filtrate may be discharged -~ at an upper part or at a lower part of the filter element.
A problem in each of these filtration apparatuses is that, ~ since the pre-coat layer i8 formed on a vertical surface at .t~ 15 any rate, the pre-coat layer sometimes falls off the surface of the filter element not only in the course of the works for the formation of the pre-coat layer of a filter aid but also during the filtering works through the thus formed pre-coat layer, e3pecially, when the liguid flow through the 20 pre-coat layer is interrupted.
In connection with the works for forming the pre-coat ~, layer of a filter aid on the surface of a filter element, it is a possible way that the dispersion of the filter aid, -~ from which the filter aid should be deposited to form the 25 pre-coat layer on the surface of the filter element, is prepared by use of a liquid which i9 the liquid to be -~ filtered therethrough. This method, in which the filter , ;~s:
. . , 132~089 1 element and the filter aid are contacted from the very beginning by the liquid to be filtered, sometimes causes problems when the amount of certain soluble materials dis-solved out from the filter aid and entering the filtrate must be limited or when microbiological contamination of the filtration system must be avoided. It is a usual practice ~` in such cases that the pre-coat layer is formed using a dispersion of the filter aid in a liquid which is not the same one as the liquid to be filtered, such as cold or hot `~ 10 water, and thereafter the liquid passing through the pre-coat layer is gradually switched to the liquid to be filtered without interrupting the liquid flow therethrough.
.~
When a process of filtration is started with formation of a pre-coat layer in the above described manner, it is an :'~
~ ` 15 unavoidable consequence that a considerably large portion ..~..
of the liquid coming out of the filter element in the course .
of the above mentioned liquid switching is a mixture of the first liquid used as the dispersing medium of the filter aid to form the pre-coat layer and the second liquid which is :,~
the liguid to be subjeCted to the filtration treatment.
~ Such a fraction of liquid mixture naturally contains the .
desired filtrate const~tuent only in a low concentration so that it is discarded as a waste or stored in a separate reservoir from which it is returned bit by bit to the ~` 25 preceding step of the process.
The above mentioned way of discarding the transitive -~ filtrate is u~desirable when the filtered liquid is very `: , ,:.
, .,- .
,. .
~ `
-1 expensive or when certain detriment is anticipated by dis-carding the liquid while the alternative way of collecting the transitive filtrate in a separate reservoir before disposal or recycling is economically disadvantageous in respect of the investment for the facilities and consumption of large manpower and time.
; In order to solve the above mentioned problem concerning the transitive filtrate which is a mixture of the liquid . used for pre-coat forming and the liquid to be filtered, l 10 a method has been proposed in ~hich the space inside the filter apparatus is pressurized with a gas such as air, carbon dioxide and the like after completion of formation of ,', the pre-coat layer on the surface of the filter element so as to discharge the liquid used for pre-coat forming. This method also cannot provide a complete solution of the problem. For example, the pre-coat layer may fall off the surface of the filter element partly or wholly during the ~,~
discharge of the liquid under pressurization or in the course of filling the filter element with the liquid to be filtered therethrough and tiny holes are sometimes formed in the ; pre-coat layer so that it is a difficult matter to keep the .. .
pre-coat layer in a complete defect-free condition. This ~ problem is particularly serious in a filtration apparatus of ;~ the type in which the filtrate i8 taken out of the apparatus ! ~ 25 at an upper part thereof.
:`
` i32~089 Accordingly, the present invention has an object to provide a filtration apparatus in which the liquid is filtered through a pre-coat layer formed on the surface of a .~. 5 filter element without the problem by the transitive filtrate which is a mixture of the liquid used in the formation of the pre-coat layer and the liquid to be ~` filtered.
In one aspect, the present invention provides a filtration apparatus comprising at least one upright tubular ..~, i~
filter element mounted in a housing, and having an outer surface on which a pre-coat layer of a filter aid is to be formed such that a liquid to be filtered is passed through said pre-coat layer and through said filter element from said outer surface toward an inner surface thereof; means ~ for feeding a liquid suspension including a liquid carrying : ~ a pre-coat material into said housing and to said at least ; one tubular filter element for forming said pre-coat layer 1 on said surface of said at least one tubular filter element;
`~ 20 means for feeding a liquid to be filtered into said housing :
;. such that said liquid to be filtered passes through said at ~. . least one precoated filter element; means for discharging .. filtrate from said at least one filter element and fro~ said ~.~ housing; means for feeding a purging gas into said tubular -. 25 hou~ing for pressurizing the interior of said housing for - removing said liquid suspension carrying said pre-coat ;, .
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, - . .
132~0~9 1 material from said tubular filter element; means for . discharging said liquid suspension from said housing; and purging gas exhaust means including a purging gas exhaust tube coupled to an opening on an upper part of said at least , 5 one tubular filter element for removing said purging gas ,~ from the inner part of said at least one tubular filter element and from the filter apparatus prior to input of the ` liquid to be filtered.
~ In another aspect, the present invention provides -~ 10 a filtration apparatus comprising at least one upright tubular filter element mounted in a housing, and having an outer surface on which a pre-coat layer of a filter aid is to be formed such that a liquid to be filtered is passed , :, through said pre-coat layer and through said filter element ., ~. 15 from said outer surface toward an inner surface thereof;
:~ means for feeding a liquid suspension including a liguid carrying a pre-coat material into said housing and to said ~
~ at least one tubular filter element for forming said pre-coat layer on said surface of said at least tubular filter ~, 20 element; means for feeding a liquid to be filtered into said ;- housing such that said liquid to be filtered passes through ~ said at least one precoated filter element; means for ; discharging filtrate from said at least one filter element ~: and from said housing; means for feeding a purging gas into said tubular housing for pressurizing the interior of said housing for removing said liquid suspension carrying said pre-coat material from said tubular filter element; means 5~ -`-',. LV~.
1 coupled to said housing for discharging said liquid suspension from said housing; and liquid drain means including a liquid drain tube coupled to an opening on a lower part of said at least one tubular filter element for . 5 draining at least said liquid carrying the inner part of said pre-coat material from the inner part of said at least one tubular filter element and from the filter apparatus prior to input of the liquid to be filtered.
~- BRIEF DESCRIPTION OF THE DRAWING
FIGURE 1 is an illustration of a flow sheet of a filtration system having a filtration apparatus according to -~ the first embodiment of the invention built therein.
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1FIGURE 2 schematically illustrates an axial cross sectional view of a filtration apparatus according to the first embodiment of the invention.
FIGURES 3a and 3b are each a detailed illustration of a part of the filtration apparatus illustrated in FIGURE 2 showing the conjunction of the gas exhaust tube and the ,~ filter element.
, FIGURE 4 is an illustration of a flow sheet of a ;~ filtration system having a filtration apparatus according ~ 10 to the second embodiment of the invention built therein.
,, FIGURE 5 schematically illustrates an axial cross sectional view of a filtration apparatus according to the second embodiment of the invention.
i~ FIGURE 6 is a detailed illustration of a part of the ~ 15 filtration apparatus illustrated in FIGURE 5 showing the conjunction of the liquid drain tube and the filter element.
FIGURE 7 i8 a detailed illustration of a part correspond-ing to FIGURE 6 of a filter element formed by spirally ' winding a wire around a-tube of a punched metal or a .;, corrugated rectangular tube showing the conjunction of the liquid drain tube and the filter element.
DETAILED DESCRIP~ON ~F THE PREFERRE~ EMBODIMENTS
In the following, the filtration apparatus of the present invention i8 described in more detail with reference to the accompanying drawing.
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t l In FIGURE 1 which is an illustration of a flow sheet of ~ a filtration system having a filtration apparatus according ,` to the first embodiment of the invention, the filtration apparatus 1 has a plural number of tubular filter elements - 5 2 each having a circular or polygonal cross section in an , upright disposition inside thereof. The upper ends of these filter elements 2 are connected to a gas exhaust tube 3 opening to the atmospheric air through a valve lle. The ,~ .
liquid to be filtered is introduced into the filtration apparatus 1 from the liquid feed line 4 through the valve llc by means of a pump 10. The pre-coat slurry contained ~--;~ in the pre-coat tank 9 is introduced into the filtration ., , ~- apparatus 1 through the valves llb and llc also by means ., ~; of the pump 10. The filtrate coming out of the filter elements 2 is discharged through the filtrate discharge tube 5 while the liquid drain line 6 with a valve lld serves to empty the filtration apparatus 1. The filtration apparatus ` ~ 1 can be pressurized with a gas through the gas feed line 7.
~ by opening the valve llf and the pressurizing gas can be -^ 20 released to the ambient atmosphere through the primary gas vent tube 8 by opening the valve llg. The system has several more valves lla, llh, lli and llj.
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FIGURE 2 schematically illustrates an axial cross . sectional view of another model of the filtration apparatus 1 and the reference numerals 2, 3 and 5 each correspond to the resp~ctive part 2, 3 or 5 in FIGURE 1. Each of the filter elements 2 has an upper and a lower end member 12a . ,.
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., , ` 132~089 -~. 1 and 12b by which it is held inside the housing of the filtra-- tion apparatus 1 provided with a pair of flanges 13 at which :~ the covering can be disassempled from the body of the apparatus 1. In the apparatus illustrated in FIGURE 2, each :~ 5 of the filter elements 2 is composed of three unit members made of a ceramic material in a tandem arrangement by fastening with the upper and lower end members 12a and 12b.
~-~ FIGURES 3a and 3b are each a detailed illustration of a . part of the apparatus shown in FIGURE 2 to demonstrate the conjunction of the gas exhaust tube 3 having a gas outlet opening 3a or 3b, respectively, to the filter element 2 by means of a spindle 14 for positioning of the filter element ~, 2, a spring 15 and a nut 16.
~,~ In FIGURE 4 which is an illustration of a flow sheet of a filtration system having a filtration apparatus according to the second embodiment of the invention, the filtration . apparatus 1 has a plural number of tubular filter elements 2 each having a circular or polygonal cross section in an upright disposition inside thereof. The lower ends of these . 20 filter elements 2 are connected to a liquid drain tube 3' opening to the atmospheric air through a valve lle. The ; liguid to be filtered is introduced into the filtration apparatus 1 from the liguid feed line 4 through the valve x: llc by means of a pump 10. The pre-coat slurry contained ~1. 25 in the pre-coat tank 9 is introduced into the filtration ~: apparatus 1 through the valve~ llb and llc al~o by means ~..
::` of the pump 10. The filtrate coming out of the filter .: .;;
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1 elements 2 is discharged through the filtrate discharge tube 5 while the liquid drain line 6 with a valve lld serves to empty the filtration apparatus 1. The filtration apparatus 1 can be pressurized with a gas through the gas feed line 7 by opening the valve llf and the pressurizing gas can be released to the ambient atmosphere through the gas vent tube 8' by opening the valve llg. The system has several more ~, valves lla, llh, lli and llj.
FIGURE 5 schematically illustrates an axial cross ~ 10 sectional view of another model of the filtration apparatus i 1 according to the second embodiment of the invention. The -~ reference numerals 2, 3' and 5 each correspond to the respective part 2, 3' or 5 in FIGURE 4. Each of the filter , elements 2 has an upper and a lower end member 12a and 12b by which it is held inside the housing of the filtration apparatus 1 provided with a pair of flanges 13 at which the conical bottom member of the housing can be disassembled from the body of the apparatus 1. Each of the filter elements 2~ i8 a cylinder made of a ceramic material and held inside ~ 20 the housing of the apparatus 1 by means of the upper and `-~ lower ena members 12a and 12b. FIGURE 6 is a detailed illustration of a part of the apparatus shown in FIGURE 5 ~- to demonstrate the conjunction of the liquid drain tube 3' ~ having an opening 3'a by means of a spindle 14 for positioning ~ 25 of the filter element 2 and a nut 16. FIGURE 7 is a detailed illustration of a part corresponding to FIGURE 6 of a filter -,~ element formed by spirally winding a wire around a tube of g _ ;~, .~
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1 a puched metal tube or a corrugated rectangular tube showing the conjunction of the liquid drain tube 3' with a liquid drain opening 3'b and the filter element 2.
Usable filter element in the inventive filtration ap-. S paratus includes a variety of known tubular ones having a circular or polygonal cross section without particular limitations. Particularly preferable filter elements are ceramic-made cylindrical elements, those formed by spirally winding a wire around a punched metal tube or a corrugated lo rectangular. Dimensions of the filter elements such as height, wall thickness, inner diameter and the like as well as the number of the filter elements uprightly installed in the filtration apparatus of the invention are not limitative and can be suitably selected to comply with the intended 15 filtration process. When the filtration apparatus has a plurality of the filter elements, each of the filter elements may be connected to a gas exhaust tube or liquid drain tube through a gas exhaust opening or liquid drain opening independently from the other filter elements. Alternatively, ~ 2b it i8 preferable that each of the filter elements is con-.~- nected at the gas exhaust or liquid drain opening to one end ~.. ~ ,.
`~ of a separate gas exhaust tube or liquid drain tube while the other ends of the gas exhaust tubes or liquid drain tubes are `~ combined in a single collecting pipe through which the gas : .
25 or liquid i8 di~charged.
The inner diameter of the gas exhaust opening or liquid `~ drain opening may be sufficient when an appropriate volume ,;~ ,~.
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1324~89 , 1 of the qas or liquid can be taken out of the filter element by pressurizing or filling the filtration apparatus with the gas or liquid. According to the results of the ex-:~ periments undertaken by the inventors, the gas exhaust ~, 't; 5 opening should preferably have an inner diameter in the ~ range from one fifteenth to one third of the inner diameter -~ of the filter element while the liquid drain opening should .i preferably have an inner diameter which is not larger than - the inner diameter of the filter element but not smaller than one twentieth of the inner diameter of the filter element. When the inner diameter of the gas exhaust opening or the liquid drain opening is outside the above mentioned respective range, the gas exhaustion or liquid drain cannot be achieved with an efficiency as high as desired. The inner diameter of the gas exhaust tube or liquid drain tube adeguately selected in consideration of the cross sectional area of the gas exhaust opening or the liquid drain opening, the number of the filter elements in the filtration apparatus ~x and other parameters. The gas exhaust tube or liquid drain `~ 20 tube should be made preferably of a stainless steel in most cases although the material may be selected depending on ? the particularly intended filtration process in which the ~ inventive filtration apparatus is used.
-~ As is described above in detail, the most characteristic ~ 25 feature of the invention consists in the gas exhaust tube or -~ liguid drain tube connected to the filter element at the .. ~, upper part or lower part, respectively, thereof to give a ~.
1 possibility of filling the filtration apparatus with the liquid to be filtered or discharging the liquid for pre-coat forming keeping the once formed pre-coat layer in a defect-; free condition. Namely, the procedures of forming of the pre-coat layer, discharging of the liquid for pre-coat forming, interruption of the liquid flow and filling of the filtra-tion apparatus with the liquid to be filtered can be performed without the problem of falling of the pre-coat layer. Thus, the filtration process using the inventive filtration apparatus can be performed without the disadvantage due to the mixture of the liquid for pre-coat forming and the liquid to be filtered otherwise unavoidable in the transitive stage. This is because, in the inventive filtration ~ apparatus, different from conventional filtration apparatuses `~ 15 utilizing a pre-coat layer, formation of the pre-coat layer can be directly followed by complete discharge of the liquid ~ .
used for the formation of the pre-coat layer out of the filtration apparatus prior to introduction of the liquid to be filtered into the apparatus without falling of the once .:
formed pre-coat layer or formation of tiny holes therein.
~- Absence of the liquid mixture otherwise produced in the ' transitive stage of switching from the liquid for pre-coat forming to the liquid to be filtered provides great ad-~i~ vantages not only relative to the costs for the disposal or recycling treatment of such a liquid mixture but also in respect of improvements in the quality of the product produced in the process involving filtration.
.. - :, ~ - 12 -A
`` 132~089 1 In the following, the filtration apparatus of the ; invention is described in more datail by way of examples.
Example 1 The filtration apparatus used in this test had 19 ceramic-made cylindrical filter elements uprightly installed in the housing. Each of the filter elements was constructed of three unit elements each having a height of 500 mm, inner diameter of 70 mm and wall thickness of 25 mm in a tandem arrangement. The spindle for positioning of the filter element was provided with a gas exhaust opening of .. .
7 mm diameter at the upper end thereof so that the gas inside the apparatus could be discharged to the outer atmo-sphere through a gas exhaust tube connected to the opening.
A filtration system was constructed using this filtration apparatus according to the flow sheet illustrated in FIGURE 1.
The pre-coat tank 9 was filled with an aqueous suspen-.~:
sion of diatomaceous earth which was circulated along a path of valve llb, pump 10, valve llc, filtration apparatus 1, . ::
filtrate discharge tube 5, valve llj and pre-coat tank 9 so ~ 20 as to form a pre-coat layer of diatomaceous earth on the ;~ outer surface of the filter elements 2.
`~ When the pre-coat layer had been completed, the valves ~; llb and llj were closed with the pump 10 turned off and, simultaneously, carbon dioxide gas was introduced into the filtration apparatus by opening the valve llf so as to ~i discharge the water for pre-coat forming by opening the t -1 valve lli. When the liquid surface in the filtration ap-paratus 1 had reached the level of the filtrate discharge tube 5, the valve lld was opened to completely discharge the remaining water. Further, the water for pre-coat forming 5 remaining in the piping between the valves lla and lld was discharged by opening the valves lla and lld for a short while followed by closing.
Thereafter, the filtration apparatus 1 was filled with beer introduced thereinto through the valve lla, pump 10 and ~;` 10 valve llc. The air inside was discharged during this procedure through the secondary gas exhaust tube 3 by opening the valve lle. After completion of filling of the ap-paratus with the beer, the beer was filtered through a path of the valve lla, pump 10, valve llc, filtration apparatus ;~ 15 1 and valve llh by simultaneously closing the valve lle and opening the valve llh.
,~ The above described filtration of beer could be performed absolutely without producing a mixture of the water for pre-coat forming and the beer and removal of the yeast contained ~ 20 in the beer was complete. No defects were found at all in : ~' the pre-coat layer during the filtration procedure such as falling of the layer and formation of tiny holes therein.
Comparative Exam~le 1 The filtration system and filtration apparatus were ~ ~ubstantially the same as in Example 1 except that the s apparatus had no secondary gas exhaust tube ~. The ~ - 14 -: ~ .
~, 132~8~
. 1 filtration apparatus was filled with beer under gas dis-' charge by opening the valve llg or the valve lli. The results of filtration were not satisfactory due to partial falling of the pre-coat layer and formation of tiny holes in the upper part of the pre-coat layer.
, .
Example 2 The filtration system was constructed according to the ~,s flow sheet illustrated in FIGURE 1 using a filtration ap-x paratus in which a single ceramic-made cylindrical filter ,::
~': lo element was installed in an upright disposition. The filter .~ element was constructed of three unit elements each having .~ a height of 500 mm, inner diameter of 70 mm and wall thick-.,,.'~.
~ ness of 25 mm in a tandem arrangement and the upper end ;; ,~
.~ member 12a of the element was provided with a gas exhaust -.'~. 15 opening of 7 mm diameter to which a gas exhaust tube was ;~: connected.
~ The procedure of filtration using the above described n~ filtration system was substantially the same as in Example 1 :~ excepting replacement of the beer with a sugar syrup and :~` 20 carbon dioxide gas with air. The results were that the :~,- .
~:. sugar syrup could be filtered without dilution by inter-~:;: mixing of water and removal of the yeast contained in the sugar syrup was complete.
~' `r Example 3 The filtration system and filtration apparatus were ~: substantially the same as in Example 1 except that the '', , - i -- 1 5 , , .
.
~32~089 1 filtration apparatus had seven filter elements each formed of a corrugated rectangular tube having a height of 700 mm, inner diameter of 26 mm and wall thickness of 2 mm spirally wound with a wire. Oolong tea was filtered using this filtration apparatus in substantially the same manner as 2 in Example 1 excepting replacement of the carbon dioxide gas -~ with nitrogen. The results were that the Oolong tea could - be filtered without dilution by intermixing of water and removal of the bacteria contained in the Oolong tea was `~ 10 complete.
,.
.
~-~ Example 4 , . .
~he filtration apparatus had seven ceramic-made cylindrical filter elements uprightly installed in the housing. Each of the filter elements had a height of 700 mm, inner diameter of 20 mm and wall thickness of 5 mm and the spindle for positioning of the filter element was -~ provided witha liquid drain opening of 7 mm diameter at the lower end of the element so that the liquid inside the apparatus could be discharged to the outside of the ap-~ 20 paratus through a liquid drain tube connected to the ,~ opening. A filtration system was constructed using this ;~ filtration apparatus according to the flow sheet illustrated in FIGURE 4.
The pre-coat tank 9 was filled with an agueous suspension of diatomaceous earth which was circulated along a path of valve llb, punp 10, valve llc, filtration apparatus 1, ,~-i . 5 -132~089 . 1 filtrate discharge tube 5, valve llj and pre-coat tank 9 so -~ as to form a pre-coat layer of diatomaceous earth on the . ::
outer surface of the filter elements 2.
' When the pre-coat layer had been completed, the valves llb and llj were closed with the pump 10 turned off and, . ~
~, simultaneously, carbon dioxide gas was introduced into the `S~ filtration apparatus 1 by opening the valve llf so as to discharge the water for pre-coat forming by opening the ~ valve lle. When the liquid surface in the filtration ap-,~ .
paratus 1 had reached the level of the liquid drain tube S 3', the valve lld was opened to completely discharge the remaining water. Further, the water for pre-coat forming ~.,;
;~ remaining in the piping between the valves lla and lld was discharged by opening the valves lla and lld for a ~; 15 short while followed by closing.
Thereafter, the filtration apparatus 1 was filled with beer introduced thereinto through the valve lla, pump 10 and ~, valve llc. The air inside was discharged during this procedure by opening the valve lli. After completion of $~
;~ 20 filling of the apparatus with the beer, the beer was ~`~ filtered through a path of the valve lla, pump 10, valve ~, llc, filtration apparatus 1 and valve llh by simultaneously -~, ~¦; closing the valve lli and opening the valve llh.
The above described filtration of beer could be performed absolutely without producing a mixture of the x~
water for pre-coat forming and the beer and removal of the yeast contained in the beer was complete. No defects were .
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132~089 . , .
1 found at all in the pre-coat layer during the filtration , procedure such as falling of the layer and formation of ;
` tiny holes therein.
.
~ Com~ tive Example 2 . , .
~' 5 The system and apparatus for the filtration of beer ~.
`, were substantially the same as in Example 4 except that the filtration apparatus had no liquid drain tube 3' and the water for pre-coat forming was discharged by opening the valves llc and lld and/or the valve lli. The results of :,~
~ 10 filtration were not satisfactory due to partial falling of `~ the pre-coat layer and formation of tiny holes in the pre-coat layer.
Example S
~ The filtration system and filtration apparatus were .,~
substantially the sama as in Example 4 except that the ~, filtration apparatus had seven filter elements each formed of a corrugated rectangular tube having a height of 700 mm, inner diameter of 26 mm and wall thickness of 2 mm spirally , . . .
-~ wound with a wire. Oolong tea was filtered using this ." ~
filtration apparatus in substantially the same manner as in Example 4 excepting replacement of the carbon dioxide ''.~' ~- gas with nitrogen. The results were that the Oolong tea ~ could7ba filtered without dilution by intermixing of water ,.,~
and removal of the bacteria contained in the Oolong tea was complete.
., , - 18 -~. ~
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BACKGROUND OF THE INVENTION
The present invention relates to a filtration apparatus or, more particularly, to an improvement of a filtration apparatus in which a so-called pre-coat layer of a filter aid is formed on the surface of a filter element or filter ' r~ medium and the liquid is filtered through the thus formed ,, .~
pre-coat layer. Filtration apparatuses of this type are widely used in the manufacturing process of alcoholic drinks such as beer, wine, Japanese sake and the like, seasonings such as soy sauce, vinegar, sugar, cooking oil and the like, other beverages such as f~uit-based drinks, carbonated ¦~ drinks, mineral water, Oolong tea and the like, phanmaceuticals and so on.
` ~. As is known, a type of filtration procedures utilizes apre-coat layer which is formed of a filter aid such as -~ diatomaceous earth, perlite, cellulosic powder, active ~ carbon and the like on the surface of filter elements in a -i ~ substantial thickness and through which the liquid is `~ filtered.
~ 20 The most conventional material as the filter element, ,,.~ , :
~ ~ on which the pre-coat layer is formed, includes filter cloth, ., ~;, , ~ filter net, filtèr paper and the like although several more ~ .. ::
rigid materials are sometimes used including punched metal ,~
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1 tubes spirally wound with a wire, corrugated rectangular tubes (or tubes having an undulate polygonal cross section) spirally wound with a wire, ceramic-made cylindrical elements and so on. Different types of the filter elements may be 5 used either alone or as a combination of two types or more.
Various types of filtration apparatuses utilize one or more of cylindrical or polygonally tubular filter elements provided with a pre-coat layer in an upright disposition.
s These filtration apparatuses are classified into two classes 10 depending on the position at which the filtrate is taken out ~ of the filter element. Namely, the filtrate may be discharged -~ at an upper part or at a lower part of the filter element.
A problem in each of these filtration apparatuses is that, ~ since the pre-coat layer i8 formed on a vertical surface at .t~ 15 any rate, the pre-coat layer sometimes falls off the surface of the filter element not only in the course of the works for the formation of the pre-coat layer of a filter aid but also during the filtering works through the thus formed pre-coat layer, e3pecially, when the liguid flow through the 20 pre-coat layer is interrupted.
In connection with the works for forming the pre-coat ~, layer of a filter aid on the surface of a filter element, it is a possible way that the dispersion of the filter aid, -~ from which the filter aid should be deposited to form the 25 pre-coat layer on the surface of the filter element, is prepared by use of a liquid which i9 the liquid to be -~ filtered therethrough. This method, in which the filter , ;~s:
. . , 132~089 1 element and the filter aid are contacted from the very beginning by the liquid to be filtered, sometimes causes problems when the amount of certain soluble materials dis-solved out from the filter aid and entering the filtrate must be limited or when microbiological contamination of the filtration system must be avoided. It is a usual practice ~` in such cases that the pre-coat layer is formed using a dispersion of the filter aid in a liquid which is not the same one as the liquid to be filtered, such as cold or hot `~ 10 water, and thereafter the liquid passing through the pre-coat layer is gradually switched to the liquid to be filtered without interrupting the liquid flow therethrough.
.~
When a process of filtration is started with formation of a pre-coat layer in the above described manner, it is an :'~
~ ` 15 unavoidable consequence that a considerably large portion ..~..
of the liquid coming out of the filter element in the course .
of the above mentioned liquid switching is a mixture of the first liquid used as the dispersing medium of the filter aid to form the pre-coat layer and the second liquid which is :,~
the liguid to be subjeCted to the filtration treatment.
~ Such a fraction of liquid mixture naturally contains the .
desired filtrate const~tuent only in a low concentration so that it is discarded as a waste or stored in a separate reservoir from which it is returned bit by bit to the ~` 25 preceding step of the process.
The above mentioned way of discarding the transitive -~ filtrate is u~desirable when the filtered liquid is very `: , ,:.
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~ `
-1 expensive or when certain detriment is anticipated by dis-carding the liquid while the alternative way of collecting the transitive filtrate in a separate reservoir before disposal or recycling is economically disadvantageous in respect of the investment for the facilities and consumption of large manpower and time.
; In order to solve the above mentioned problem concerning the transitive filtrate which is a mixture of the liquid . used for pre-coat forming and the liquid to be filtered, l 10 a method has been proposed in ~hich the space inside the filter apparatus is pressurized with a gas such as air, carbon dioxide and the like after completion of formation of ,', the pre-coat layer on the surface of the filter element so as to discharge the liquid used for pre-coat forming. This method also cannot provide a complete solution of the problem. For example, the pre-coat layer may fall off the surface of the filter element partly or wholly during the ~,~
discharge of the liquid under pressurization or in the course of filling the filter element with the liquid to be filtered therethrough and tiny holes are sometimes formed in the ; pre-coat layer so that it is a difficult matter to keep the .. .
pre-coat layer in a complete defect-free condition. This ~ problem is particularly serious in a filtration apparatus of ;~ the type in which the filtrate i8 taken out of the apparatus ! ~ 25 at an upper part thereof.
:`
` i32~089 Accordingly, the present invention has an object to provide a filtration apparatus in which the liquid is filtered through a pre-coat layer formed on the surface of a .~. 5 filter element without the problem by the transitive filtrate which is a mixture of the liquid used in the formation of the pre-coat layer and the liquid to be ~` filtered.
In one aspect, the present invention provides a filtration apparatus comprising at least one upright tubular ..~, i~
filter element mounted in a housing, and having an outer surface on which a pre-coat layer of a filter aid is to be formed such that a liquid to be filtered is passed through said pre-coat layer and through said filter element from said outer surface toward an inner surface thereof; means ~ for feeding a liquid suspension including a liquid carrying : ~ a pre-coat material into said housing and to said at least ; one tubular filter element for forming said pre-coat layer 1 on said surface of said at least one tubular filter element;
`~ 20 means for feeding a liquid to be filtered into said housing :
;. such that said liquid to be filtered passes through said at ~. . least one precoated filter element; means for discharging .. filtrate from said at least one filter element and fro~ said ~.~ housing; means for feeding a purging gas into said tubular -. 25 hou~ing for pressurizing the interior of said housing for - removing said liquid suspension carrying said pre-coat ;, .
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132~0~9 1 material from said tubular filter element; means for . discharging said liquid suspension from said housing; and purging gas exhaust means including a purging gas exhaust tube coupled to an opening on an upper part of said at least , 5 one tubular filter element for removing said purging gas ,~ from the inner part of said at least one tubular filter element and from the filter apparatus prior to input of the ` liquid to be filtered.
~ In another aspect, the present invention provides -~ 10 a filtration apparatus comprising at least one upright tubular filter element mounted in a housing, and having an outer surface on which a pre-coat layer of a filter aid is to be formed such that a liquid to be filtered is passed , :, through said pre-coat layer and through said filter element ., ~. 15 from said outer surface toward an inner surface thereof;
:~ means for feeding a liquid suspension including a liguid carrying a pre-coat material into said housing and to said ~
~ at least one tubular filter element for forming said pre-coat layer on said surface of said at least tubular filter ~, 20 element; means for feeding a liquid to be filtered into said ;- housing such that said liquid to be filtered passes through ~ said at least one precoated filter element; means for ; discharging filtrate from said at least one filter element ~: and from said housing; means for feeding a purging gas into said tubular housing for pressurizing the interior of said housing for removing said liquid suspension carrying said pre-coat material from said tubular filter element; means 5~ -`-',. LV~.
1 coupled to said housing for discharging said liquid suspension from said housing; and liquid drain means including a liquid drain tube coupled to an opening on a lower part of said at least one tubular filter element for . 5 draining at least said liquid carrying the inner part of said pre-coat material from the inner part of said at least one tubular filter element and from the filter apparatus prior to input of the liquid to be filtered.
~- BRIEF DESCRIPTION OF THE DRAWING
FIGURE 1 is an illustration of a flow sheet of a filtration system having a filtration apparatus according to -~ the first embodiment of the invention built therein.
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1FIGURE 2 schematically illustrates an axial cross sectional view of a filtration apparatus according to the first embodiment of the invention.
FIGURES 3a and 3b are each a detailed illustration of a part of the filtration apparatus illustrated in FIGURE 2 showing the conjunction of the gas exhaust tube and the ,~ filter element.
, FIGURE 4 is an illustration of a flow sheet of a ;~ filtration system having a filtration apparatus according ~ 10 to the second embodiment of the invention built therein.
,, FIGURE 5 schematically illustrates an axial cross sectional view of a filtration apparatus according to the second embodiment of the invention.
i~ FIGURE 6 is a detailed illustration of a part of the ~ 15 filtration apparatus illustrated in FIGURE 5 showing the conjunction of the liquid drain tube and the filter element.
FIGURE 7 i8 a detailed illustration of a part correspond-ing to FIGURE 6 of a filter element formed by spirally ' winding a wire around a-tube of a punched metal or a .;, corrugated rectangular tube showing the conjunction of the liquid drain tube and the filter element.
DETAILED DESCRIP~ON ~F THE PREFERRE~ EMBODIMENTS
In the following, the filtration apparatus of the present invention i8 described in more detail with reference to the accompanying drawing.
~, - 6 -`~
:, ., 132~0~89 ;`
t l In FIGURE 1 which is an illustration of a flow sheet of ~ a filtration system having a filtration apparatus according ,` to the first embodiment of the invention, the filtration apparatus 1 has a plural number of tubular filter elements - 5 2 each having a circular or polygonal cross section in an , upright disposition inside thereof. The upper ends of these filter elements 2 are connected to a gas exhaust tube 3 opening to the atmospheric air through a valve lle. The ,~ .
liquid to be filtered is introduced into the filtration apparatus 1 from the liquid feed line 4 through the valve llc by means of a pump 10. The pre-coat slurry contained ~--;~ in the pre-coat tank 9 is introduced into the filtration ., , ~- apparatus 1 through the valves llb and llc also by means ., ~; of the pump 10. The filtrate coming out of the filter elements 2 is discharged through the filtrate discharge tube 5 while the liquid drain line 6 with a valve lld serves to empty the filtration apparatus 1. The filtration apparatus ` ~ 1 can be pressurized with a gas through the gas feed line 7.
~ by opening the valve llf and the pressurizing gas can be -^ 20 released to the ambient atmosphere through the primary gas vent tube 8 by opening the valve llg. The system has several more valves lla, llh, lli and llj.
. ~).
FIGURE 2 schematically illustrates an axial cross . sectional view of another model of the filtration apparatus 1 and the reference numerals 2, 3 and 5 each correspond to the resp~ctive part 2, 3 or 5 in FIGURE 1. Each of the filter elements 2 has an upper and a lower end member 12a . ,.
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., , ` 132~089 -~. 1 and 12b by which it is held inside the housing of the filtra-- tion apparatus 1 provided with a pair of flanges 13 at which :~ the covering can be disassempled from the body of the apparatus 1. In the apparatus illustrated in FIGURE 2, each :~ 5 of the filter elements 2 is composed of three unit members made of a ceramic material in a tandem arrangement by fastening with the upper and lower end members 12a and 12b.
~-~ FIGURES 3a and 3b are each a detailed illustration of a . part of the apparatus shown in FIGURE 2 to demonstrate the conjunction of the gas exhaust tube 3 having a gas outlet opening 3a or 3b, respectively, to the filter element 2 by means of a spindle 14 for positioning of the filter element ~, 2, a spring 15 and a nut 16.
~,~ In FIGURE 4 which is an illustration of a flow sheet of a filtration system having a filtration apparatus according to the second embodiment of the invention, the filtration . apparatus 1 has a plural number of tubular filter elements 2 each having a circular or polygonal cross section in an upright disposition inside thereof. The lower ends of these . 20 filter elements 2 are connected to a liquid drain tube 3' opening to the atmospheric air through a valve lle. The ; liguid to be filtered is introduced into the filtration apparatus 1 from the liguid feed line 4 through the valve x: llc by means of a pump 10. The pre-coat slurry contained ~1. 25 in the pre-coat tank 9 is introduced into the filtration ~: apparatus 1 through the valve~ llb and llc al~o by means ~..
::` of the pump 10. The filtrate coming out of the filter .: .;;
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1 elements 2 is discharged through the filtrate discharge tube 5 while the liquid drain line 6 with a valve lld serves to empty the filtration apparatus 1. The filtration apparatus 1 can be pressurized with a gas through the gas feed line 7 by opening the valve llf and the pressurizing gas can be released to the ambient atmosphere through the gas vent tube 8' by opening the valve llg. The system has several more ~, valves lla, llh, lli and llj.
FIGURE 5 schematically illustrates an axial cross ~ 10 sectional view of another model of the filtration apparatus i 1 according to the second embodiment of the invention. The -~ reference numerals 2, 3' and 5 each correspond to the respective part 2, 3' or 5 in FIGURE 4. Each of the filter , elements 2 has an upper and a lower end member 12a and 12b by which it is held inside the housing of the filtration apparatus 1 provided with a pair of flanges 13 at which the conical bottom member of the housing can be disassembled from the body of the apparatus 1. Each of the filter elements 2~ i8 a cylinder made of a ceramic material and held inside ~ 20 the housing of the apparatus 1 by means of the upper and `-~ lower ena members 12a and 12b. FIGURE 6 is a detailed illustration of a part of the apparatus shown in FIGURE 5 ~- to demonstrate the conjunction of the liquid drain tube 3' ~ having an opening 3'a by means of a spindle 14 for positioning ~ 25 of the filter element 2 and a nut 16. FIGURE 7 is a detailed illustration of a part corresponding to FIGURE 6 of a filter -,~ element formed by spirally winding a wire around a tube of g _ ;~, .~
.~, .
1 a puched metal tube or a corrugated rectangular tube showing the conjunction of the liquid drain tube 3' with a liquid drain opening 3'b and the filter element 2.
Usable filter element in the inventive filtration ap-. S paratus includes a variety of known tubular ones having a circular or polygonal cross section without particular limitations. Particularly preferable filter elements are ceramic-made cylindrical elements, those formed by spirally winding a wire around a punched metal tube or a corrugated lo rectangular. Dimensions of the filter elements such as height, wall thickness, inner diameter and the like as well as the number of the filter elements uprightly installed in the filtration apparatus of the invention are not limitative and can be suitably selected to comply with the intended 15 filtration process. When the filtration apparatus has a plurality of the filter elements, each of the filter elements may be connected to a gas exhaust tube or liquid drain tube through a gas exhaust opening or liquid drain opening independently from the other filter elements. Alternatively, ~ 2b it i8 preferable that each of the filter elements is con-.~- nected at the gas exhaust or liquid drain opening to one end ~.. ~ ,.
`~ of a separate gas exhaust tube or liquid drain tube while the other ends of the gas exhaust tubes or liquid drain tubes are `~ combined in a single collecting pipe through which the gas : .
25 or liquid i8 di~charged.
The inner diameter of the gas exhaust opening or liquid `~ drain opening may be sufficient when an appropriate volume ,;~ ,~.
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1324~89 , 1 of the qas or liquid can be taken out of the filter element by pressurizing or filling the filtration apparatus with the gas or liquid. According to the results of the ex-:~ periments undertaken by the inventors, the gas exhaust ~, 't; 5 opening should preferably have an inner diameter in the ~ range from one fifteenth to one third of the inner diameter -~ of the filter element while the liquid drain opening should .i preferably have an inner diameter which is not larger than - the inner diameter of the filter element but not smaller than one twentieth of the inner diameter of the filter element. When the inner diameter of the gas exhaust opening or the liquid drain opening is outside the above mentioned respective range, the gas exhaustion or liquid drain cannot be achieved with an efficiency as high as desired. The inner diameter of the gas exhaust tube or liquid drain tube adeguately selected in consideration of the cross sectional area of the gas exhaust opening or the liquid drain opening, the number of the filter elements in the filtration apparatus ~x and other parameters. The gas exhaust tube or liquid drain `~ 20 tube should be made preferably of a stainless steel in most cases although the material may be selected depending on ? the particularly intended filtration process in which the ~ inventive filtration apparatus is used.
-~ As is described above in detail, the most characteristic ~ 25 feature of the invention consists in the gas exhaust tube or -~ liguid drain tube connected to the filter element at the .. ~, upper part or lower part, respectively, thereof to give a ~.
1 possibility of filling the filtration apparatus with the liquid to be filtered or discharging the liquid for pre-coat forming keeping the once formed pre-coat layer in a defect-; free condition. Namely, the procedures of forming of the pre-coat layer, discharging of the liquid for pre-coat forming, interruption of the liquid flow and filling of the filtra-tion apparatus with the liquid to be filtered can be performed without the problem of falling of the pre-coat layer. Thus, the filtration process using the inventive filtration apparatus can be performed without the disadvantage due to the mixture of the liquid for pre-coat forming and the liquid to be filtered otherwise unavoidable in the transitive stage. This is because, in the inventive filtration ~ apparatus, different from conventional filtration apparatuses `~ 15 utilizing a pre-coat layer, formation of the pre-coat layer can be directly followed by complete discharge of the liquid ~ .
used for the formation of the pre-coat layer out of the filtration apparatus prior to introduction of the liquid to be filtered into the apparatus without falling of the once .:
formed pre-coat layer or formation of tiny holes therein.
~- Absence of the liquid mixture otherwise produced in the ' transitive stage of switching from the liquid for pre-coat forming to the liquid to be filtered provides great ad-~i~ vantages not only relative to the costs for the disposal or recycling treatment of such a liquid mixture but also in respect of improvements in the quality of the product produced in the process involving filtration.
.. - :, ~ - 12 -A
`` 132~089 1 In the following, the filtration apparatus of the ; invention is described in more datail by way of examples.
Example 1 The filtration apparatus used in this test had 19 ceramic-made cylindrical filter elements uprightly installed in the housing. Each of the filter elements was constructed of three unit elements each having a height of 500 mm, inner diameter of 70 mm and wall thickness of 25 mm in a tandem arrangement. The spindle for positioning of the filter element was provided with a gas exhaust opening of .. .
7 mm diameter at the upper end thereof so that the gas inside the apparatus could be discharged to the outer atmo-sphere through a gas exhaust tube connected to the opening.
A filtration system was constructed using this filtration apparatus according to the flow sheet illustrated in FIGURE 1.
The pre-coat tank 9 was filled with an aqueous suspen-.~:
sion of diatomaceous earth which was circulated along a path of valve llb, pump 10, valve llc, filtration apparatus 1, . ::
filtrate discharge tube 5, valve llj and pre-coat tank 9 so ~ 20 as to form a pre-coat layer of diatomaceous earth on the ;~ outer surface of the filter elements 2.
`~ When the pre-coat layer had been completed, the valves ~; llb and llj were closed with the pump 10 turned off and, simultaneously, carbon dioxide gas was introduced into the filtration apparatus by opening the valve llf so as to ~i discharge the water for pre-coat forming by opening the t -1 valve lli. When the liquid surface in the filtration ap-paratus 1 had reached the level of the filtrate discharge tube 5, the valve lld was opened to completely discharge the remaining water. Further, the water for pre-coat forming 5 remaining in the piping between the valves lla and lld was discharged by opening the valves lla and lld for a short while followed by closing.
Thereafter, the filtration apparatus 1 was filled with beer introduced thereinto through the valve lla, pump 10 and ~;` 10 valve llc. The air inside was discharged during this procedure through the secondary gas exhaust tube 3 by opening the valve lle. After completion of filling of the ap-paratus with the beer, the beer was filtered through a path of the valve lla, pump 10, valve llc, filtration apparatus ;~ 15 1 and valve llh by simultaneously closing the valve lle and opening the valve llh.
,~ The above described filtration of beer could be performed absolutely without producing a mixture of the water for pre-coat forming and the beer and removal of the yeast contained ~ 20 in the beer was complete. No defects were found at all in : ~' the pre-coat layer during the filtration procedure such as falling of the layer and formation of tiny holes therein.
Comparative Exam~le 1 The filtration system and filtration apparatus were ~ ~ubstantially the same as in Example 1 except that the s apparatus had no secondary gas exhaust tube ~. The ~ - 14 -: ~ .
~, 132~8~
. 1 filtration apparatus was filled with beer under gas dis-' charge by opening the valve llg or the valve lli. The results of filtration were not satisfactory due to partial falling of the pre-coat layer and formation of tiny holes in the upper part of the pre-coat layer.
, .
Example 2 The filtration system was constructed according to the ~,s flow sheet illustrated in FIGURE 1 using a filtration ap-x paratus in which a single ceramic-made cylindrical filter ,::
~': lo element was installed in an upright disposition. The filter .~ element was constructed of three unit elements each having .~ a height of 500 mm, inner diameter of 70 mm and wall thick-.,,.'~.
~ ness of 25 mm in a tandem arrangement and the upper end ;; ,~
.~ member 12a of the element was provided with a gas exhaust -.'~. 15 opening of 7 mm diameter to which a gas exhaust tube was ;~: connected.
~ The procedure of filtration using the above described n~ filtration system was substantially the same as in Example 1 :~ excepting replacement of the beer with a sugar syrup and :~` 20 carbon dioxide gas with air. The results were that the :~,- .
~:. sugar syrup could be filtered without dilution by inter-~:;: mixing of water and removal of the yeast contained in the sugar syrup was complete.
~' `r Example 3 The filtration system and filtration apparatus were ~: substantially the same as in Example 1 except that the '', , - i -- 1 5 , , .
.
~32~089 1 filtration apparatus had seven filter elements each formed of a corrugated rectangular tube having a height of 700 mm, inner diameter of 26 mm and wall thickness of 2 mm spirally wound with a wire. Oolong tea was filtered using this filtration apparatus in substantially the same manner as 2 in Example 1 excepting replacement of the carbon dioxide gas -~ with nitrogen. The results were that the Oolong tea could - be filtered without dilution by intermixing of water and removal of the bacteria contained in the Oolong tea was `~ 10 complete.
,.
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~-~ Example 4 , . .
~he filtration apparatus had seven ceramic-made cylindrical filter elements uprightly installed in the housing. Each of the filter elements had a height of 700 mm, inner diameter of 20 mm and wall thickness of 5 mm and the spindle for positioning of the filter element was -~ provided witha liquid drain opening of 7 mm diameter at the lower end of the element so that the liquid inside the apparatus could be discharged to the outside of the ap-~ 20 paratus through a liquid drain tube connected to the ,~ opening. A filtration system was constructed using this ;~ filtration apparatus according to the flow sheet illustrated in FIGURE 4.
The pre-coat tank 9 was filled with an agueous suspension of diatomaceous earth which was circulated along a path of valve llb, punp 10, valve llc, filtration apparatus 1, ,~-i . 5 -132~089 . 1 filtrate discharge tube 5, valve llj and pre-coat tank 9 so -~ as to form a pre-coat layer of diatomaceous earth on the . ::
outer surface of the filter elements 2.
' When the pre-coat layer had been completed, the valves llb and llj were closed with the pump 10 turned off and, . ~
~, simultaneously, carbon dioxide gas was introduced into the `S~ filtration apparatus 1 by opening the valve llf so as to discharge the water for pre-coat forming by opening the ~ valve lle. When the liquid surface in the filtration ap-,~ .
paratus 1 had reached the level of the liquid drain tube S 3', the valve lld was opened to completely discharge the remaining water. Further, the water for pre-coat forming ~.,;
;~ remaining in the piping between the valves lla and lld was discharged by opening the valves lla and lld for a ~; 15 short while followed by closing.
Thereafter, the filtration apparatus 1 was filled with beer introduced thereinto through the valve lla, pump 10 and ~, valve llc. The air inside was discharged during this procedure by opening the valve lli. After completion of $~
;~ 20 filling of the apparatus with the beer, the beer was ~`~ filtered through a path of the valve lla, pump 10, valve ~, llc, filtration apparatus 1 and valve llh by simultaneously -~, ~¦; closing the valve lli and opening the valve llh.
The above described filtration of beer could be performed absolutely without producing a mixture of the x~
water for pre-coat forming and the beer and removal of the yeast contained in the beer was complete. No defects were .
~' . ,.
'-:
~ '. .
132~089 . , .
1 found at all in the pre-coat layer during the filtration , procedure such as falling of the layer and formation of ;
` tiny holes therein.
.
~ Com~ tive Example 2 . , .
~' 5 The system and apparatus for the filtration of beer ~.
`, were substantially the same as in Example 4 except that the filtration apparatus had no liquid drain tube 3' and the water for pre-coat forming was discharged by opening the valves llc and lld and/or the valve lli. The results of :,~
~ 10 filtration were not satisfactory due to partial falling of `~ the pre-coat layer and formation of tiny holes in the pre-coat layer.
Example S
~ The filtration system and filtration apparatus were .,~
substantially the sama as in Example 4 except that the ~, filtration apparatus had seven filter elements each formed of a corrugated rectangular tube having a height of 700 mm, inner diameter of 26 mm and wall thickness of 2 mm spirally , . . .
-~ wound with a wire. Oolong tea was filtered using this ." ~
filtration apparatus in substantially the same manner as in Example 4 excepting replacement of the carbon dioxide ''.~' ~- gas with nitrogen. The results were that the Oolong tea ~ could7ba filtered without dilution by intermixing of water ,.,~
and removal of the bacteria contained in the Oolong tea was complete.
., , - 18 -~. ~
~' .,~
Claims (11)
1. A filtration apparatus comprising:
at least one upright tubular filter element mounted in a housing, and having an outer surface on which a pre-coat layer of a filter aid is to be formed such that a liquid to be filtered is passed through said pre-coat layer and through said filter element from said outer surface toward an inner surface thereof;
means for feeding a liquid suspension including a liquid carrying a pre-coat material into said housing and to said at least one tubular filter element for forming said pre-coat layer on said surface of said at least one tubular filter element;
means for feeding a liquid to be filtered into said housing such that said liquid to be filtered passes through said at least one precoated filter element;
means for discharging filtrate from said at least one filter element and from said housing;
means for feeding a purging gas into said tubular housing for pressurizing the interior of said housing for removing said liquid suspension carrying said pre-coat material from said tubular filter element;
means for discharging said liquid suspension from said housing; and purging gas exhaust means including a purging gas exhaust tube coupled to an opening on an upper part of said at least one tubular filter element for removing said purging gas from the inner part of said at least one tubular filter element and from the filter apparatus prior to input of the liquid to be filtered.
at least one upright tubular filter element mounted in a housing, and having an outer surface on which a pre-coat layer of a filter aid is to be formed such that a liquid to be filtered is passed through said pre-coat layer and through said filter element from said outer surface toward an inner surface thereof;
means for feeding a liquid suspension including a liquid carrying a pre-coat material into said housing and to said at least one tubular filter element for forming said pre-coat layer on said surface of said at least one tubular filter element;
means for feeding a liquid to be filtered into said housing such that said liquid to be filtered passes through said at least one precoated filter element;
means for discharging filtrate from said at least one filter element and from said housing;
means for feeding a purging gas into said tubular housing for pressurizing the interior of said housing for removing said liquid suspension carrying said pre-coat material from said tubular filter element;
means for discharging said liquid suspension from said housing; and purging gas exhaust means including a purging gas exhaust tube coupled to an opening on an upper part of said at least one tubular filter element for removing said purging gas from the inner part of said at least one tubular filter element and from the filter apparatus prior to input of the liquid to be filtered.
2. The filtration apparatus of claim 1, wherein:
said pre-coat is applied to an outer surface of said at least one tubular filter element; and said filtrate discharging means and said purging gas exhaust means are coupled to remove said filtrate and said purging gas, respectively, from the interior of said at least one tubular filter element.
said pre-coat is applied to an outer surface of said at least one tubular filter element; and said filtrate discharging means and said purging gas exhaust means are coupled to remove said filtrate and said purging gas, respectively, from the interior of said at least one tubular filter element.
3. The filtration apparatus of claim 2, wherein said filtrate discharging means is coupled to a lower part of said at least one tubular filter element.
4. The filtration apparatus of claim 2, further comprising a further gas exhaust means coupled to said housing for exhausting gas from said housing exterior of said at least one filter element.
5. The filtration apparatus of claim 1, further comprising a further gas exhaust means coupled to said housing for exhausting gas from said housing exterior of said at least one filter element.
6. A filtration apparatus comprising:
at least one upright tubular filter element mounted in a housing, and having an outer surface on which a pre-coat layer of a filter aid is to be formed such that a liquid to be filtered is passed through said pre-coat layer and through said filter element from said outer surface toward an inner surface thereof;
means for feeding a liquid suspension including a liquid carrying a pre-coat material into said housing and to said at least one tubular filter element for forming said pre-coat layer on said surface of said at least one tubular filter element;
means for feeding a liquid to be filtered into said housing such that said liquid to be filtered passes through said at least one precoated filter element;
means for discharging filtrate from said at least one filter element and from said housing;
means for feeding a purging gas into said tubular housing for pressurizing the interior of said housing for removing said liquid suspension carrying said pre-coat material from said tubular filter element;
means coupled to said housing for discharging said liquid suspension from said housing; and liquid drain means including a liquid drain tube coupled to an opening on a lower part of said at least one tubular filter element for draining at least said liquid carrying the inner part of said pre-coat material from the inner part of said at least one tubular filter element and from the filter apparatus prior to input of the liquid to be filtered.
at least one upright tubular filter element mounted in a housing, and having an outer surface on which a pre-coat layer of a filter aid is to be formed such that a liquid to be filtered is passed through said pre-coat layer and through said filter element from said outer surface toward an inner surface thereof;
means for feeding a liquid suspension including a liquid carrying a pre-coat material into said housing and to said at least one tubular filter element for forming said pre-coat layer on said surface of said at least one tubular filter element;
means for feeding a liquid to be filtered into said housing such that said liquid to be filtered passes through said at least one precoated filter element;
means for discharging filtrate from said at least one filter element and from said housing;
means for feeding a purging gas into said tubular housing for pressurizing the interior of said housing for removing said liquid suspension carrying said pre-coat material from said tubular filter element;
means coupled to said housing for discharging said liquid suspension from said housing; and liquid drain means including a liquid drain tube coupled to an opening on a lower part of said at least one tubular filter element for draining at least said liquid carrying the inner part of said pre-coat material from the inner part of said at least one tubular filter element and from the filter apparatus prior to input of the liquid to be filtered.
7. The filtration apparatus of claim 6, wherein:
said pre-coat is applied to an outer surface of said at least one tubular filter element; and said filtrate discharging means and said liquid drain means are coupled to remove said filtrate and at least said liquid of said liquid suspension, respectively, from the interior of said at least one tubular filter element.
said pre-coat is applied to an outer surface of said at least one tubular filter element; and said filtrate discharging means and said liquid drain means are coupled to remove said filtrate and at least said liquid of said liquid suspension, respectively, from the interior of said at least one tubular filter element.
8. The filtration apparatus of claim 7, wherein said filtrate discharging means is coupled to an upper part of said at least one tubular filter element.
9. The filtration apparatus of claim 7, further comprising a gas exhaust means coupled to said housing for exhausting purging gas from said housing exterior of said at least one filter element.
10. The filtration apparatus of claim 6, further comprising a gas exhaust means coupled to said housing for exhausting purging gas from said housing exterior of said at least one filter element.
11. The filtration apparatus of claim 6, wherein at least said liquid of said liquid suspension is removed from said at least one filter element by means of said filtrate discharging means during forming of said pre-coat layer.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5602686U JPS62170117U (en) | 1986-04-16 | 1986-04-16 | |
| JP56026/1986 | 1986-04-16 | ||
| JP68850/1986 | 1986-05-09 | ||
| JP1986068850U JPH0328888Y2 (en) | 1986-05-09 | 1986-05-09 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1324089C true CA1324089C (en) | 1993-11-09 |
Family
ID=26396939
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000529802A Expired - Fee Related CA1324089C (en) | 1986-04-16 | 1987-02-16 | Filtration apparatus |
Country Status (3)
| Country | Link |
|---|---|
| AU (1) | AU582297B2 (en) |
| CA (1) | CA1324089C (en) |
| DE (1) | DE3763365D1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116116108A (en) * | 2023-02-28 | 2023-05-16 | 深圳惠科新材料有限公司 | Diatomite filter and application method thereof |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU584743B2 (en) * | 1986-01-31 | 1989-06-01 | Schewitz, Jonathan | Filtering unit |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA1120867A (en) * | 1978-03-08 | 1982-03-30 | Robert E. Loudon | Two layer wound-on-core medium filter element |
| CA1110181A (en) * | 1978-05-04 | 1981-10-06 | Joseph F. Giannelli | Filter element with slotted precoat retainer sheet |
-
1987
- 1987-02-10 DE DE8787101791T patent/DE3763365D1/en not_active Expired - Fee Related
- 1987-02-16 CA CA000529802A patent/CA1324089C/en not_active Expired - Fee Related
- 1987-02-24 AU AU69173/87A patent/AU582297B2/en not_active Ceased
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116116108A (en) * | 2023-02-28 | 2023-05-16 | 深圳惠科新材料有限公司 | Diatomite filter and application method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| DE3763365D1 (en) | 1990-08-02 |
| AU582297B2 (en) | 1989-03-16 |
| AU6917387A (en) | 1987-12-03 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |