FR2545374A1 - APPARATUS FOR FILTERING PLASTIC MATERIAL WITH LEVEL RECORDS - Google Patents

Abstract

FILTERING APPARATUS IN TRANSPARENT PLASTIC MATERIAL PROVIDED WITH FILLING LEVEL MARKS. THE UPPER TRANSPARENT PART 5 IS OF A TRUNCONIC SHAPE WITH FOUR STAGES 1, 2, 3, 4. THE STEPPED DISCHARGES FORM THREE LEVEL MARKS M1, M2, M3 OVER THE ENTIRE PERIOD. THE LOWER STAGE M1 HAS A CAPACITY OF APPROXIMATELY 50ML, THE TWO STAGES M1, M2 HAVE A TOTAL CAPACITY OF APPROXIMATELY 75ML AND THE TOTAL CAPACITY OF THE THREE STAGES M1, M2 AND M3 IS ABOUT 100ML, THE UPPER STAGE 4 HAVING A CAPACITY OF 10 TO 30ML. USE IN PARTICULAR FOR STERILE FILTERING, STERILIZATION CONTROL AND INCUBATION OF LIQUID SAMPLES.

Description

The invention relates to a device for filtering plastic material with a

  an upper transparent box-shaped body and an inlet manifold and a plurality of filling level markers formed in the wall of the chamber for measured filling volumes and a filter element which separates the upper part of the box into two chambers; a part

  lower box with outlet, hermetically fixed to the

superior.

  According to the state of the art according to the German patent,

  2 334 375 and the German utility model 80 14 162, such devices are used for example to concentrate liquid media, so as to, for example, push the concentration of aqueous solutions far enough to allow to perform on these solutions microbiological research In order to be able to also control from the outside by optical means

  different degrees of concentration- it is foreseen in the

  king of the filtering container mark marks that are either printed, or directly embedded in the plastic or made in relief in the form of graduation lines While it is true that these marks facilitate optical control, they require because of their and their size to carry out their direct observation at a very short distance. In the normal practice of laboratory

  person is responsible for monitoring several batteries of

  such considerations, which, given the different

  chronological differences in the concentration process, represents a heavy burden for the staff of the

service or supervision.

  Such containers and filter sets are also used for sterile filtering and sterilization control

  of liquid substances Devices and examples of use

  Such applications have already been described in US Pat. No. 3,448,011, German Offenlegungsschrift No. 2,549,835 and German Patent Application No. 3,012,085. The closed cylindrical boxes made of transparent plastics material are provided with inlet and outlet ports. exit, are fulfilled in

  sterile conditions with the liquid to be filtered and after

  preliminary concentration of the liquid, it is chosen a height of

  determined level which itself corresponds to a specific level

  born and makes it possible to draw conclusions on the content of germs or impurities of the liquid when the residue remaining on the filtering agent is studied qualitatively and quantitatively in the laboratory To detect any microorganisms that may have remained on the filtering agent, the procedure is usually to fill the sterile closure-filled cans with culture broth, and then the sample is incubated directly

  boxes under aerobic or aneorobic conditions; because of

  of the cylindrical shape of the dishes, the surface of the liquid is the same in the case of aerobic incubation and anaerobic incubation, whereas it would be desirable for the aerobic incubation of the surface of the oxygen-absorbing liquid to be as large as possible and, on the contrary, as small as possible for the anaerobic incubation Incubation of the samples is carried out simultaneously in several boxes under different conditions and with different culture broths in order to facilitate the control and to be able to ascertain more easily whether there are

  microorganisms and germs and, if so, to determine

  what are these microorganisms and germs.

  In an apparatus for filtering (DE-U 81 010 7) according to a prior art, the upper part of the box-shaped body has an outside diameter of about 50 mm and a height of 90 mm. The level marks are directed in the direction of the longitudinal axis of the box and are arranged in a

  as a marking block on the front half of the

  on the other hand on the posterior half of the envelope or on the entire envelope Two or three identical filtering devices of this kind are connected by flexible connections and by a common injection cannula to form a unit of sale and use so that when the operator installs these boxes in series on a nozzle device, he must take care that the level marks are visible at least on the front side, which is not always ensured by following

  stiffness in the hose system.

  It is an object of the invention to create with simple means a filtering apparatus provided with level marks which, in the circumferential direction of the transparent box, are not

  not attached to isolated peripheral segments-and are

  visible, and which share the contents of the upper part of the device body in volumes having liquid-free surfaces of different sizes. In addition, the invention also proposes to facilitate as much as possible the handling and

  to improve other qualities of functioning, such as

air-conditioning and de-aerating.

  This result is obtained by the invention thanks to a

  filtering apparatus made of plastics material with a higher

  a box-shaped transparent body and inlet manifold and a plurality of fill level marks formed in the wall of the chamber for measured filling volumes and a filter element which separates in two chambers the upper part of the box from a lower part of a box with an outlet, hemertically fixed to the upper part, characterized in that the transparent top box part is made up of a hollow truncated four-storey cone whose stepped recesses form peripheral filling level marks on the first floor frustoconical lower neighbor of the large ba E having a filling capacity from the filtering plane

  from the filter to the first step stall of about 50 ml.

  the second and first frustoconical stages together having a total capacity of about 75 ml, the third, second, and frustoconical first stage together having a total capacity of about 100 ml or alternatively about 110 ml; and the capacity of the last frustoconical floor up to the ceiling of the

can being about 10 to 20 ml.

  The advantages of this form of container lie in the fact that, on the periphery of the box, the level marks are everywhere visible as well and with a relatively large filter area in the area of the base of the box, the free liquid surface decreases in steps as the hat is approached, so that in aerobic incubation, with a reduced height level, the free surface size grading better gas exchange and that in the case of anaerobic incubation, with a height of more than 70 ml, a smaller free surface is available, which is a barrier to gas exchange and absorption. As a result of a possible reinforcement of the container in the area of the fill level steps and the magnification shape given to the transitions, it is possible, on the one hand, to increase the strength of the container and, on the other hand, to on the other hand, to improve optical control

in the landmarks area.

  For vacuum filtration and incubation under aerobic conditions, the filtering structure of the ventilation and de-aerating filter in the upper part of the box is designed in such a way as to exclude any risk of blockage.

  complete the hydrophobic filter membrane if, when filling

  the hand mixture of the broth, liquid coming out of the upper part of the box had to penetrate

  the lower plane of the hydrophobic filter membrane.

  Thanks to the shape given by the invention to the filter support, to its free spaces and to the connecting channels with

  the gas chamber of the liquid reservoir is prevented from

  The filling of the free spaces with liquid when, for example to intimately mix the contents of the box, the box-shaped filtering device with the contained liquid and the integrated gas filter is carefully stirred according to standard laboratory methods. However, it happens in fact that under extreme conditions or as a result of improper handling of the apparatus to be filtered, liquid reaches the plane of the hydrophobic membrane, the mobile membrane provided between the two filter supports caused by its pumping motion at alternative pressures the emptying of the free spaces of the support of

  filter, so that ventilation and

  even under extreme conditions.

  The features and advantages of the invention

  will come out from the following description, as a

  for example, with reference to the accompanying drawing in which: Figure 1 shows in vertical section the filter apparatus hermetically sealed and sterilized; Figure 2 shows in detail a section of the junction zone between the upper part of the box and the lower part of the box, and a step recess variant; Figure 3 is a vertical sectional view along the line 3/4 of Figure 5 of a small separate filter in three parts for filtering gas; FIG. 4 is a vertical sectional view along line 3/4 of FIG. 5 of a small filter for aerating and de-aerating a closed filter box, integrated into a large filter body; FIG. is a view from above in the line of FIGS. 3 and 4 of the lower filter support located on the gas and liquid tank side, the filter blank and the upper part of the box being removed; FIGS. 6 and 7 show in top view respectively two kit variants each composed of three filtering apparatus connected so as to form a unit, which are

set in a shop.

  The filtering apparatus consists essentially of the box-shaped upper part S, made of transparent plastic, preferably clear, of the lower part of the

  box 14 with porous filter support 18 with lower chamber

  15, and the filter element 19 of 50 mm diameter sandwiched between the upper part and the lower part 14 The upper part of the body or upper part of the box 5 has the shape of a trunk

  of four-storey hollow cone with grained

  din with a draft of 1 form peripheral filling level marks Ml, M 2, 113, the first frustoconical lower stage 1 associated with the large base and the lower body part or lower part of the box 14 having a capacity of about 50 ml from the plane of

  filtering the filter 19 to the first truncated recess

  Ml, the second frustoconical floor and the first floor

  together having a capacity of about 75 ml, and the three first

  first frustoconical floors 1, 2 and 3 having a total capacity

  about 100 ml, or alternatively about 110 ml.

  cited the last frustoconical floor 4 up to the ceiling of the

box 6 is about 10 to 20 ml.

  The inlet tubing 7 which protrudes out of the ceiling of the body 6 is disposed against the inner body wall

  of the upper frustoconical stage 4 and, by its other extreme

  7 ', goes up to a level of about 5 ml maximum.

  above the last level mark M 3 inside the upper level stage 4 which acts as a sort of gas collecting chamber when the level of filtered liquid introduced reaches the third level mark M 3 II As a result, the filling liquid flows along the inner wall of the can without causing too much splashing when the liquid exits the hose.

  filling it under the effect of the pressure of the pump.

  In the ceiling of the body 6 is disposed another tubular

  The connection piece 8, which is hermetically connected to a sterile ventilation and de-aerating filter by means of a luer cone 9 'and a thread 10 ". The filtering plane of the hydrophobic filter 10' is located much higher than the level of the filter. highest filling in the upper part of the

  which, as a result, even when

  In the upper part 5 of the box, the liquid can not wet the hydrophobic filter membrane 10 and therefore can not obstruct it.

  venting and de-aerating filter 10 can be closed hermetically

  with such a closure 13 Such a small filter is

  shown more clearly in Figure 3.

  The inlet tubing 7 is a flexible tubing connector for a refill hose 11 which in turn terminates in an injection cannula 21 or other junction adapter commonly used in the laboratory, and is provided with A peelable protective film 22 With the aid of commercial type hose clamps 20, the filling hose 11 can be closed by throttling in any desired manner.

  where the filling hose can be inserted

  in a flexible roller tube pump so that the apparatus to be filtered can be pressurized, or

  Instead of using a flexible tube pump, the tubing of

  16 which is in the lower part of the box 14 can be connected to a vacuum source The connection pipe 16 is also closed by means of a cap

  closure 17 and forms the filtrate outlet.

  As shown in Figure 2, following a mode of

  different from that shown in Figure 1, it is possible to obtain in the zone level

  M 3 a wall thickening 50 thanks to the fact that the dia-

  meters of adjacent frustoconical stages overlap in the area of the level markers Ml, M 2, M 3 by an equal amount

  to 1 to 2 times the wall thickness In addition to a reinforcing effect

  in the area of this connecting site which, like a corset, can stabilize and reinforce relatively thin-walled boxes, it is also possible to obtain

  to a suitable curvature shape a magnifying glass effect which

  cilite the observation of the plane of the filling level.

  In the particular case of the sterilization control, the best results have been obtained with hydrophilic membrane filters 19 which have a hydrophobic marginal zone 19 'and, with this marginal zone, form the actual sealing zone of the filtering element 19 As shown in FIGS. 1 and 2, the hydrophobic marginal zone 19 'is wedged between the upper part 5 of the box and the lower part 14 of the box, and more specifically by the peripheral flanges 5', 14 ' taking place

  In order to ensure also the resistance to the pressure of the

  like to filter along the longitudinal axis, one of the two

  edges 5 "of the two box parts 5, 14 fit together with

  the outer edge 14 'of the other box part 14 in the axial direction and possibly in addition in the radial direction to further improve this resistance to pressure, so that

  the hydrophobic marginal zone 19 'of the filter element 19

  The bottom is kept airtight and shielded from the atmosphere surrounding the body 5, 14 by the edge of one of the body parts 5 which fits axially and optionally radially. over the edge of the other

  body portion 14 being welded or glued thereon.

  This is a preferred binding mode if it is anticipated at first sight to use the apparatus to be filtered as a lost article.

  the one shown in Figure 2 is the lower part

  box 14 which has the flange engaging by means of

  on the other, so that the lower box portion 14 is bowl-shaped. Such an embodiment is also

  to be adopted when the upper part 5 and the lower part

  14 must be separably assembled using a bayonet socket or a screw lock.

  With elastic sealing washer With

  Likewise, the truncated conical shape with peripheral level marks according to the invention also provides

the benefits described.

  Due to the fact that the small filter 10 used as a filter

  The ventilation and de-aerating head is attached to the coupling 8 but can be separated from it if necessary, it is advantageous, after the end of the incubation and after having withdrawn the small filter 10, to take the connecting pipe 8 syringe or pipette of the samples, and the

  consider for quantitative and / or qualitative analysis.

  According to FIGS. 3 and 4, the upper part 12 of the body of the small filter 10 provided with a gas inlet / outlet 12 'is constituted by a one-piece plastic molded part whose side adjacent to the filter membrane 10' has a plurality of ribs 28 which form the support of the filter itself, and a plurality of free spaces

  29 which are connected to the input / output 12 '.

  28 which supports the flat filter blank 10 'is generally convex in the shape of a meniscus (concave) with respect to the flat face and the closed surface of the lower support

  filter 31 of the lower box portion 9 and 6 of

  that the flat filter blank 10 'which is sandwiched between the peripheral flanges 34, 34' of the two box parts 12 and 9 or 12 and 6 can move axially between the two filter supports 28, 31 flat filter blank

  'can therefore perform under the effect of

  alternating a kind of pumping movement between the two filter supports 28, 31 The two box parts

  12.9 or 12.6 are connected to their periphery in a totally

  sealed by gluing or ultrasonic welding by a

  collar 35 'or 35 standing vertically.

  The lower part of the box 9 according to FIG. 3 and the cap 6 of the box-shaped filtering device according to FIG.

  Figure 4 show respectively in relation to the

  upper section of the box 12 a small concentric piercing 27 ", 27 'whose size is determined according to the viscosity of the liquid F contained in the liquid reservoir

  4, so that only a drop of liquid F 'relatively

  This small hole can fill this bore 27 ", 271 as shown in FIG. 4 if, when the liquid F is shaken, splashing reaches the cap 6 or reaches

  the tubing 9 'If, for example, the liquid F is a solution

  aqueous injection for infusion, this piercing 27 ', 27 "preferably

  diameter of 2 m M over a total length of 2 mm.

  The filter support 31 itself for a relatively low specific clean flat filtering blank forms a planar surface and is interrupted only by a single annular channel 33 in the region of the periphery of the flat filter blank 10 'and by at least one

  connecting channel 32 which establishes the link between the

  nular 33 and the hole 27 ', 27 "with the collector channel.

  As seen in Figure 5, the filter support 31 is interrupted by four junction channels 32 which cloverleaf share the filter support 31 forming four

annular segments.

  The collecting channel 27 ', 27 "terminates substantially on the channel bottom at the inlet 30 of the secondary channels 32 which, starting from an inlet width 30 of 1 mm, go into

  widening towards the annular channel 33 to reach

  dre a width of 3 to 5 m depending on the diameter of the filter.

  With a filter with a total diameter of 25 mm, the bottom

  the canal, starting from a depth of 0.5 mm, falls

  rection of the annular channel to a depth of 1.3 mm.

  Here too, the parameters indicated are adapted to the viscosity

of an aqueous solution.

  In the area of the collecting channel 27 ', 27 ", the bottom of the connecting channel 32 is located at about 0.3 to 0.8 mm and preferably at 0.5 mm below the filter support plane,

  and, in the direction of the annular channel 33, it lowers and

  It has a depth of up to 1.1 to 1.6 mm, preferably 1.3 mm. For a total diameter of 25 mm, the annular channel is at least 2 mm wide and 1.3 mm deep. 30 of the connecting channels opening into the collecting channel 27 ', 27 "is narrower than the opening of the collecting channel 27', 27" in this zone and is narrower than the diameter of a

  drop of liquid F 'from the liquid reservoir which is itself

  same function of the viscosity of the liquid The top of the

  concavity formed by the curved filter support 28 of the

  upper tie 12 is located about 0.5 to 2 mm above the flat filter blank 10 'resting on the support

  lower filter 31 and, in the marginal part, the

  holds upper filter 28 is located from 0.1 mm to 0.2 mm

  above the plane of the flat filter blank 10 'With the

  lume box indicated, the filter membrane 10 'has the advantage

  advantageously a diameter of between 10 and 25 mm.

  According to FIGS. 3 and 4, the flat filter blank 10 '

  is shown applied against the upper filter support.

  This case occurs when the pressure of the gas in the tubulu-

  9 'or in the gas and liquid tank 4 according to

  gures 1 and 4 is greater than the gas pressure in the

  connection pipe 12 'or respectively in the atmosphere.

  This situation occurs for example when the large filter body 5, 14 according to FIGS. 1 and 4 is pressurized, the outlet pipe 12 'being closed, to discharge the liquid F as quickly as possible through the membrane. hydrophilic filter 19 in the bottom of the device 14, 15, 18 On the other hand, the flat filter blank 10 'is applied against the flat lower filter support 31 when, the tube 12' being open, the liquid F is sucked through the filter membrane 19 by a source of

  vacuum connected in the bottom of the box 14, 15, 18.

  If one or more drops F 'actually penetrated

  in the free spaces 32, 33, the drop of liquid F 'se-

  divided at the link channel inputs 30 and distributed

  in the connecting channels 32 and the annular channel 33 without the entire surface of the flat filter blank 10 'being wetted by the drop of fractionated liquid F' or

  this surface remains wet in places.

  days of the regions of the flat filter blank 10 'in the area of the free spaces 27', 27 ", 32 and 33, and also in the area of the flat filter support 31 itself which are free of liquid, so that the membrane hydrophobic filter is assured of being able to play its functional role even in

boundary conditions.

  For flat filter blanks with relatively high intrinsic strength, that is to say those which are reinforced by fibers or fabric, the flat filter blank 10 'according to FIG. 4 is supported only upwards. by the party

  upper box 12 of the small filter 10, that is to say

  The pressure coming from the upper part of the box 5 when the apparatus is pressurized by the inlet pipe 7, 7 'The bore 27' according to FIG. 4 is enlarged to the edge of the annular channel 33 (see 27 "') so that

  the free filter surface is completely unobstructed for

  change of gases There is no lasting wetting of 1 '

  hydrophobic filter element The charge of the filter element

  10 'which occurs as a result of the necessary ventilation

  the tubing 12 'remains weak when the application

  like to filter works by aspiration (by the exit 16)

  or must be ventilated for aerobic incubation.

  selected box, the flat filter blank has

  a diameter of between 10 and 25 mm.

  For the particular case of a sterilization check, the whole of the filter unit represented by the figures

  1 to 4 is sterilized, closed and sterile packed.

  According to FIG. 6, three filtering apparatuses according to FIG. 1 are connected in a functional unit equipped with a common injection cannula 21, by the flexible filling tubes 11, the branch 24 and the filling hose segment. 1 the, the whole being maintained in the

  store 25, 26 The store 25, 26 is constituted by a

  Bottom-shaped cup-shaped tie 25 adapted to the shape

  outside of the apparatus to be filtered, and by a

  cover 25 connected to flanges of the lower part 25 which forms a hermetically sealed envelope, sterilized,

  for apparatus and parts of apparatus which are also

  his. According to FIG. 7, and in a similar manner to the figures

  1 and 6, it is shown as a unit of

  positive according to Figure 4 with small filter integrated in the cover 6 With the exception of the connecting adapter 23,

  there is a concordance with the hoses and the world store

  in FIG. 6 For a set consisting of: 2

  boxes with flexible hoses 11, 24 reduced in con-

  sequence, the magazine 25, 26 is of reduced width.

Claims (13)

  1 Filtering apparatus made of plastics material with a   upper body transparent box-shaped tie and a   inlet manifold and several fill level markers   formed in the wall of the chamber for measured filling volumes and a filter element which separates in two   chambers the upper part of the box of a lower part   box with outlet, hermetically fixed to the upper part   characterized in that the transparent upper box portion (5) is constituted by a four-stage hollow cone frustum whose stepped recesses form peripheral fill level markers (M1-X3), the frustoconical first stage. (1) lower neighbor of the great   base having a filling capacity from the thread plane   trage of the filter (19) until the first step stall   (Mi) of approximately 50 ml, the second and first   (1 and 2) together having a total capacity of about   75 ml, the third, the second and the first   truncated cone (1, 2, 3) together with a total capacity of   100 ml viron or alternatively about 110 ml; and the capacity of the last frustoconical stage (4) up to the ceiling of the box (6) being from about 10 to 20 ml.   Filtering apparatus according to claim 1, characterized   in that the inlet pipe (7, 7 ') protruding   out of the hat (6) of the box is arranged directly   the inner box wall of the frustoconical upper stage (4) and protrudes inside the box in this stage to a level of about 5 ml maximum above the   highest fill mark (143).   Filtering apparatus according to claim 1 or 2,   characterized in that the stepped recesses are chamfered at least on the inside of the upper part of the box (5) and connect progressively with the   surface of the adjacent frustoconical stage (1, 2, 3, 4).   Filter apparatus according to any of the claims   cations 1 to 3, characterized in that the diameter of   The steps in steps differ from a frustoconical one (1 to 4) to the next frustoconical one (1 to 4) of an amount equal to   one to two times the wall thickness of the box.   Filtering apparatus according to any one of claims 1 to 4, characterized in that the frustoconical stages (1 to 4) by a thickening (50) of the box wall at the transition locations between a frustoconical stage (1 to 4 ) and the following, form in the manner of a corset a strengthening of the box, which can be positively and negatively charged by the pressure along the length of the box.   Filtering apparatus according to any one of the   cations 1 to 5, characterized in that the filtering diameter of the filter (19) in the lower part (14) of the box is between 40 and 60 mm and that the body of the part   upper part of the box (5) makes an angle of 0.5 to 2 port to the vertical axis.   Filtering apparatus according to claim 1, characterized rised in that it comprises:   a) a lower boot portion (14) provided with a tubular   the exit lure (16) which can be closed and a support   filter element (18) forming a small chamber (15) and   carrying a hydrophilic filter membrane (19) having a   between 0.2 and 0.45 pm, which has a zone   hydrophobic peripheral (19 '), hermetically sealed   sandwiched between the lower edge (5 ') of the part   upper box (15) and the upper edge (14 ') of the   bottom tie (14) between flanges and ribs   Circumferential (5 ', 14'), the diaphragm (19) forming   selective permeability ration between the upper (5) and lower (14) limb parts, the edge (5 ") of one of the two   box parts (5 ') interlocking axially, and optionally   additionally radially over the edge (14 ') of the other   part (14) so that the marginal part (19 ') is   metically isolated, against any diffusion, the atmosphere outside the boot, the axially nested edges and possibly radially being welded or glued together; b) a small filter (10) equipping the boot hat (6)   and constituting a ventilation filter and de-aerating, with a membrane   hydrophobic plane (10 '), with a pore thickness between 0.2 and 0.45 im, wedged by its edge between a casing part   upper bracket (12) comprising filter support (28)   (29) and connecting pipe (12 '), and a part   lower case (6,9), these two parts (12; 6,9)   linked together by their lateral edges;   a flexible hose for filling the upper part of the   box re (5) which upstream ends either in a cannula   injection nozzle (21) or in a connecting adapter (23).   Filtering apparatus according to claim 7, characterized   in that the membrane (10 ') of the small filter is made   the lower housing part (6) forms an integral part   hat (6) and consists of an opening   circular in this one, with a surface corresponding to   to that of the free surface of the filter membrane te (10 ').   Filtering apparatus according to claim 7, characterized   in that: dl) the lower part of the small filter housing (6, 9) has a filter support (31) with a flat face and a closed surface and the free spaces of the filter support are formed by a single channel annular (33) of at least 3   mm wide in the area of the periphery of the filament blank   flat tracing (10 ') and at least one connecting channel (32) which connects the annular channel (33) to the collecting channel (27', 27 ") leading to the inside of the box; d 2) the channel link (32) widens from the outlet of the collector channel where it preferably has a width of 1 mm in the direction of the annular channel (33) where it reaches a width preferably of 3 mm, for a filter diameter which can up to 25 mm; d 3) in the area of the collecting channel (27 ') the bottom of the connecting channel is 0.3 to 0.8 mm, preferably 0.5 mm below the plane of the filter support and then down towards the annular channel (33) to a depth of 1.1 mm to 1.6 mi, preferably 1.3 mm d 4) the passage section of the collecting channel (27 ') is going   narrowing from its wide base towards the reservoir   see liquid (4) inside the box, directly in the area of the filter support (31), thus passing over a   length preferably 2 mm, with a diameter of preferably equivalent to 2 mm.   Apparatus according to claim 9, characterized in   what the top hat (6) of the upper part (5)   carries a second connecting pipe (8) with a cone   luer or net, for the tight connection, but de-   mountable if necessary, the small filter (10). 11 Apparatus according to claim 9, characterized in that the lower casing part (6) of the small filter   (10) is an integral part of the hat (6).   Filtering apparatus according to claim 8 or 9,   with a small filter (10) as a filter for ventilation and   erage, characterized in that the channel width of at least 2 to 4 mm.   Apparatus for filtering according to a cation 8 to 10, characterized in that (32) diametrically opposed share (31) of the lower portion of the box or annular segments.   Apparatus for filtering according to a cation 8 to 11, characterized in that (31) of the lower part of the cloverleaf bundle by three or four annular (33) has a any of the claims   two connecting channels the filter support (6,9) in any two sectors the support (6, 9) is channels of: claims   shared filter in Link (32),   forming three or four ring segments, the collector channel   tor (27 ', 27 ") being arranged centrally.   Apparatus for filtering according to any one of   8 to 12, characterized in that the supporting plane of the filter support (28) in the upper part of the box (12) is curved in the shape of a meniscus (concave) with respect to the filter support (31) of the lower part of box   (6, 9) and at the top is about 0.5 to 2 mm below   above the flat filter blank (10 ') resting on the lower filter support (31), and in the marginal zone of the support is just above the plane of the flat filter blank, or in this plan.   Filtering apparatus according to any of the claims   8 to 13, characterized in that the inlet (30) of the connecting channels (31) opening into the collecting channel (27 ', 27 ") is narrower than the opening of the collecting channel (27', 27"). ) in this area, and smaller than the diameter of a drop   liquid (F ') from the liquid reservoir (4).   17 Set or set of double or multiple units   filtering according to any one of claims 9 to 10,   characterized in that, a current divider (or   (24) being interposed between the flexible hoses of   pleating (16 'from the top of the box of   each of the apparatuses and a flexible hose 1 connected to it   nule (21) or the adapter (23), the unit forms a unit   of closed and sterile use which is fixed in a   sin (25, 26) sterilized and hermetically closed