A method of storing a material other than gaseous in shut-off condition in a container, which material is withdrawn portion-wise from the container, as well as an apparatus for performing the method

Abstract

 A method of storing a material other than gaseous in shut-off condition in a container, said material having a quality decreasing as a result of exposure to the atmosphere, in which the material is brought into the container, the container is shut off and the material is subsequently withdrawn in a number of stages portion-wise from the container, while in the periods between the withdrawal of the material from the container, the remaining material is kept in shut off condition in the container, wherein at least during the periods between the withdrawal of the material from the container, said material is prevented from interacting with the air column in the container.

Description

[0001] The invention relates to a method of storing a material other than gaseous in shut-off condition in a container, said material being of decreasing quality owing to exposure to the atmosphere, while the material is introduced in the container, the container is shut off and the material is withdrawn portion-wise in a number of stages from the container, while in the periods between the withdrawal of the material from the container, the remaining material is stored in shut-off condition in the container.

[0002] Various solid and liquid materials are known that - not being bulk materials - are made available or are stored in packing units of limited extent by the factory or the eventual user, the quality of these materials strongly depending on the presence in the material of certain volatile substances. These materials are often used in small portions,with the result that the package, which is normally fitted with a closure member, such as a cover, and wherein the materials are stored, is frequently opened and closed. When the package is opened, the volatile substances accummulated in the air column above the material in the package will escape in a quantity corresponding with the tendency of the volatile substance of attaining an equilibrium with the remainder thereof in the material to the atmosphere. According as the package becomes emptier and the volume of the air column above the material in the package increas the loss of volatile substances each time the package is opened will likewise increase and the quality of the material will accordingly decrease at an accellerated pace.

[0003] Examples of materials of the above-mentioned type can be found in the field of foodstuffs and luxury foods, e.g. coffee, tea, cocoa,(cut) tobacco. Such materials contain flavorants which easily volatilize in the atmospher₄ and/or should have a specific moisture content.

[0004] Within the group of technical materials can be mentioned for instance certain types of liquid lacquer and paint materials. These materials, as regards their processibility, should have specific rheological properties which are mostly set and obtained by means of a mixture of solvents. These solvents are each more or less volatile, partly for imparting the desired drying properties to the paint or the lacquer. For a good quality of the eventual hardened lacquer or paint layer it may moreover be important that the mutual quantity ratios of the various solvents in the paint or the lacquer are maintained within certain limits.

[0005] Moreover, certain components from the lacquer and paint materials, upon exposure to air, may react already in the package with e.g. the oxygen component from the air, so that also in this manner the quality of the respective lacquer or paint material is negatively influenced. Also wine can be mentioned as an example within this scope.

[0006] It is an object of the invention to provide a novel method and a novel apparatus for performing the method of storing in shut-off condition a material of any of the above mentioned types, by means of which the respective material can be maintained substantially in a fresh supply condition or at factory quality in a simple manner and with simple means during the consumption of the material by the eventual consumer or user.

[0007] To this effect according to the invention there is provided a method of the above described type which is characterized in that at least during the periods between the withdrawal of the material from the container, this material is prevented from interacting with the air column in the container.

[0008] The invention also relates to an apparatus for performing the method according to the invention, said apparatus comprising a hollow container fitted with a side wall closed all around, a closed bottom end and an open top end and which is characterized in that it comprises a follower to be installed in the container, functioning as a guards member with which the container in a cross-section thereof can be practically shut-off, while the follower is movable with the level of the material available in the container and furthermore is provided with fixing means through which the position of the follower can be fixed or removed.

[0009] According to a further embodiment of the apparatus according to the invention described in the above, the follower can be placed and fixed by means of the fixing means at an adjustable pressure against the surface of the material for confining the material under pressure between the bottom of the container and the follower.

[0010] By exposing the material to be stored in the container via the follower to pressure, also the air present in particular in the top layer between the particles, fibres or threads, in case the material is particulate, filamentary or fibrous is expulsed to a lesser or greater extent. This further reduces the chance that volatile substances pass from the material to be stored in the container into the air or the chance that the air acts on certain components in the material.

[0011] Although the container of the apparatus according to the invention is not restricted to a specific form and e.g. may be square in cross-section, it is effective to design the container as a straight cylinder and the follower as a piston, with the fixing means being a sealing cup projecting all around beyond the circumference of the follower and whose outer circumference is larger than the inner circumference of the container wall.

[0012] The material from which the sealing cup is made is tuned to the properties of the material from which the container is made. If the container is made of a material resulting in a sidewall of a, particularly radially, relatively slight flexibility, e.g. tin, then a material will be chosen for the manufacture of the cup of relatively large flexibility and vice versa. Naturally, care will be taken in the choice of the material from which the container and the other parts associated with the apparatus according to the invention are made, that these materials will not adversely affect the material to be stored in the apparatus.

[0013] The apparatus according to the invention can furthermore be designed in such a manner that the sealing cup forms part of a plate or ring and the piston-like follower is divided and is right-angled to the axis thereof, and is provided with clamping means through which the plate or ring can be clamped between the follower portions.

[0014] According to a further embodiment, the sealing cup forms part of an endless hollow hose of flexible material, which hose is adapted to be clamped with the clamping means between the follower portions along the edges thereof and which has an outer circumference which, owing to the clamping pressure between the follower portions, can be extended to a length larger than the inner circumference of the container wall. This embodiment has the advantage that by removal of the clamping pressure, the outer circumference of the sealing cup becomes so much shorter that the follower can easily move up and down in the container and thus be brought into the container or be removed therefrom, while in case the material in the container is pressed by means of the follower, the air expulsed from the material can easily escape between the container wall and the sealing cup to the atmosphere.

[0015] It will be clear that in the embodiment of the apparatus according to the invention wherein this is provided with a follower with sealing cup to be installed in the container, a cover with which the open top end of the container can be separately shut off can be dispensed with in principle. For the arrangement with the follower, via the fixing means and through the sealing cup clampingly fixed all around along the inner wall of the container, blocks an open communication of the material to be stored in the container and the surroundings. For esthetical reasons or for instance also for preventing intrusion of dust in the container, it may be advantageous to nevertheless fit the apparatus with a cover, the cover and the container being fitted with members to be urged into coaction,through which the open top end of the container can be closed or released by the cover. In such a case, it is preferred,from the viewpoint of an effective handling of the apparatus, that the follower,at the end facing away from the material to be stored in the container, is connected to a rod which is conducted via an opening in the cover through the cover in a manner movable within the opening. The position of the follower can thus be adjusted from the outside and be fixed via the fixing means from the outside. Moreover, in such a case the fixing means can also be urged to engage the rod exteriorly beyond the cover, e.g. by means of a clamping lever pivotally connected to the cover. The dimensions of the follower may be chosen in such a manner that the follower along its circumference precisely abuts against the inner circumference of the container wall. The follower itself may be made in its entirety of a more or less thick sheet material, while a sufficient rigidity can be obtained by using stiffening ribs.

[0016] It may be felt advantageous by the user of an apparatus according to the invention, e.g. a pipe smoker wishing to fill his pipe with tobacco from the tobacco stock stored in the container of the apparatus, if, for getting at the tobacco, he is not obliged to also first operate or remove the follower.

[0017] In such a case it is advantageous to replace the bottom of the container by or to design the same as the follower. The open top end of the container offering direct access to the tobacco store, is then fitted with a cover a part of which is thickened at the end facing towards the bottom, as is known per se, in such a manner that the thickening functions as a spacer for preventing the tobacco filling from extending to the upper edge of the container. As a result, spilling problems are prevented. In the latter embodiment, for reasons analogous to those necessitating the provision of a cover for the apparatus according to the invention, with which the top end of the container is closable, the apparatus according to the invention may be provided with a second cover, now to shut off the open bottom end.

[0018] A liquid such as wine is mostly filled in bottles made available to the consumer. It often occurs that the user considers the quantity of wine available in the bottom too large for consumption at one go. The wine in a bottle once opened, as is generally known, is perishable however partly owing to reactions that may occur between one or more components from the air and one or more substances in the wine affecting its taste. The wish of the consumer to put aside in such a case a bottle still partly filled with wine without affecting the quality of the wine, can be met within the scope of the apparatus according to the invention with a follower of an adjusted type to be installed in the bottle, said follower being composed of an inflatable balloon whose neck is connected to a tube by means of which the balloon can be inflated from outside the container.

[0019] When inflating the balloon, this normally swells up and, after having reached a given increase in volume, will lie against the inner wall of the bottle and against the liquid level, at more or less pressure. The balloon-shapalfollower can be maintained in this position in a very-simple manner by rotating the tube about its longitudinal axis, so that the inflatable neck is twisted and sealed up. The resilience of the inflatable neck of the balloon is too small to overcome the torsional force against the resistance offered by the much heavier tube. The position of the follower is thus fixed. For removing the follower, the tube need only be rotated in opposite sense until the passage through the inflatable neck of the balloon is again released and the air from the balloon can flow out to the atmosphere.

[0020] By applying the apparatus according to the invention, fitted with a follower as explained in the above, the possibility of an interaction between the material to be stored in the container and the air column in the container is practically inexistent, since the connection between the two is completely blocked. Such an interaction appears also inexistent, at least to have been reduced strongly, if in the absence of a follower, it is ensured that the air column in the container,after having been filled with a material to be stored, e.g. ground coffee, is blocked off from further contact with the surroundings by means of a guard member. It is assumed that in such a case, after insertion of the ground coffee in the container and e.g. closure of the open top end of the container with a cover, true, there will initially occur a certain interaction between the air column blocked off from the surroundings and the coffee, but that this interaction decreases in course of time and finally ceases when an equilibrium condition has been reached between the compositions of the air column and the coffee. In accordance with the above therefore a different embodiment of the apparatus according to the invention is that which comprises a hollow container fitted with a sidewall closed all around, a closed bottom end, an open top end and a guard member, in particular a cover, with which the open communication of the container with the surroundings can be closed or opened, and furthermore characterized in that the bottom of the container contains an opening which is blocked off from an open communication with the atmosphere by a gate. Preferably, the hollow container belonging to this embodiment of the apparatus according to the invention is cylindrical and the apparatus is furthermore characterized by a scraper member operable from the outside, comprising a rod conducted via an opening in the cover through the cover in a manner rotatable within the opening, said rod being fitted at the part extendable in the container- with one or more scraper blades; the connecting chamber of the gate is rotatable about the axis of the container as rotation axis and is divided in a plurality of sub-chambers of substantially equal volume; the operating means with which the connecting chamber is rotatable between a loading position or an unloading position, as well as a receptacle wherein the material can be unloaded in the unloading position of the connecting chamber.

[0021] In the apparatus according to the invention described in the preceding paragraph, the entire coffee stock present in the container can be discharged portion-wise to the outside without it being necessary to open the cover with which the container is shut off. By dividing the contents of the connecting chamber of the gate into a plurality, e.g. four, of chambers of equal size, each corresponding with a quantity of ground coffee for e.g. two cups of coffee, the apparatus according to the invention also functions as metering apparatus.

[0022] If desired, the climate of the air column above the material to be stored in the container, e.g. gromdcoffee, can be artificially adjusted in respect of e.g. the degree of humidity and/or the content of the volatile flavorants. In the space above the coffee there is installed to this effect an air-condition member containing a mixture of these components in a suitable package. The respective volatile flavorants in preferably concentrated form and in well chosen mutual quantity ratios and possibly moisture are given up . from the package to the surrounding air in the air column. Thus, the delivery of the corresponding components from the ground coffee is counter-acted and/or any leakage losses of these substances to the surroundings are compensated.

[0023] The air-condition member may have any desired form and e.g. comprise a loose reservoir or a reservoir to be attached e.g. to the follower, the cover or the container wall, said reservoir being internally provided with absorbing material for absorbing the respective components and a wall of which is provided with e.g. holes or a porous, sintered material through which said components can controllably escape to the surrounding air column. It is preferred if the reservoir can be opened, so that the mixture of substances escaped therefrom in course of time can be replenished.

[0024] A number of embodiments of the apparatus according to the invention will now be described, by way of example, with reference to the accompanying drawings, in which:

Fig. 1 diagrammatically shows a longitudinal section of a box containing a cover suitable for storing tobacco and fitted with a follower;

Fig. 2 diagrammatically shows a longitudinal section of a cover-containing box suitable for storing a liquid, such as a lacquer and fitted with a follower comprising a balloon;

Fig. 3 diagrammatically shows a longitudinal section of a storage box for coffee to be used as metering apparatus;

Fig. 4 is an exploded cross-sectional view of a metering member to be used in combination with a storage box according to Fig. 3;

Fig. 5 is a top view of the scraper as a component of the metering member shown in Fig. 4;

Fig. 6 is a part-sectional view of a follower to be used in a container of the apparatus according to the invention; and

Fig. 7 is an axial cross-section of a different embodiment of a follower to be used in a container of the apparatus according to the invention.

[0025] In the drawing, 1 shows a cylindrical box and 2 a cover with which the box can be closed and opened via a screw stopper, not further shown.

[0026] The combination of box 1 and cover 2, as shown in Fig. 1, is made of tin material and is suitable for storing cut tobacco. The follower 5 is made of sheet material, while the stiffening ribs 10 provide sufficient rigidity to the follower. The diameter of the follower 5 is chosen in such a manner that it abuts all around against the inner wall of the box 1. The follower 5 is connected to a metal push rod 3, which is divided. The push rod portions 3a and 3b are telescopically interconnected and can occupy two relative positions under the influence of the action of a coil spring, not further shown, i.e. the position in which the push rod portion 3b lies substantially entirely within the push rod portion 3a, and the position in which the push rod portion 3b is in a maximally extended position relative to the push rod portion 3a and in which this position is secured by means of the sliding bush 4 against collapse in the transition area between the push rod portions 3a and 3b. By means of the two thus adjustable lengths of the push rod, it is possible to bridge the entire height inside the box to the level of the ground coffee stored in the box.

[0027] The cover 2 is likewise provided with stiffening ribs 11 at the inside thereof. Through the cover there is centrally installed a guide bush 12 which is fixedly connected to the cover and the stiffening ribs 11. The push rod portion 3a is conducted through the guide bush 12, while the internal diameter of the guide bush 8 and the external diameter of the push rod portion 3a are tuned to each other in such a manner that the push rod portion 3a is slidable up and down with a sliding fit through the guide bush 8.

[0028] The end of push rod portion 3a situated beyond the cover 2 is fitted with control knob 7.

[0029] At 6 is indicated a strip-like clamping lever which is pivotally connected to the support 13, which in its turn is fixedly connected to the cover.

[0030] The push rod portion 3a is conducted through an opening provided in the clamping lever strip 6, said opening being dimensioned in such a manner that the assembly of push rod and follower pressed at a given pressure against the level of the coffee in the box, is fixed in that position by clamping action of the push rod in the lever opening.

[0031] The operation of the storage box in Fig. 1 is as follows. When the cover 2 is removed, cut tobacco deprived of the factory packing is loosely put in the box 1 as far as about 2 cm underneath the upper edge of the box. Subsequently, cover 2 provided with an injected compound ring for better sealing of the upper edge of the box 1, is screwed onto the bush after the push rod has been adjusted to the smallest length thereof. Via the push rod 3, the follower 5 is pressed against the tobacco, thereby compressing the same. Subsequently, the position of the push rod with follower is fixed by means of the clamping lever 6.

[0032] During the compression, the air escaping from the tobacco can escape upwardly along the circumference.

[0033] When a quantity of tobacco is to be withdrawn from the box, the clamping lever 6 is pressed downwards, thereby removing the clamping action of the push rod. The cover 2 is unscrewed and the assembly of cover with push rod and follower is removed, after which the tobacco is accessible, etc...

[0034] At 9 is shown a reservoir which is fixedly connected to the follower, and wherein a composite mixture of flavorants, water and possibly other desirable substances can be provided, which mixture can escape controllably via the perforated top end of the reservoir to the air column above the follower.

[0035] Fig. 2 shows a vessel 1 of circular cross-section which is closable by cover 2. The vessel 1 and cover 2 are fitted with screw thread, not further shown, allowing the cover 2 to be screwed onto or unscrewed from the vessel by a helical motion.

[0036] An access tube 15 is provided centrally through cover 2 and is fixedly connected to the cover.

[0037] In the vessel 1 there is stored a bottling stock of wine 20 from which selectively limited quantitiescan be poured out.

[0038] 16 Indicates an assembly of a balloon 17 serving as follower and an inflatable tube 19, the inflatable neck 18 of the balloon 17 being pushed about an end portion of the tube 19. The balloon 17, as shown in Fig. 1, is in the inflated condition, thereby abutting against the liquid level and the inner wall of the vessel 1. By rotation of the inflatable tube 19 about its longitudinal axis, the inflatable neck 18 of the balloon is twisted in the area 22 and is squeezed tight, so that the air under pressure in the balloon cannot escape.

[0039] In this condition the vessel can be left to itself without further aids.

[0040] If a quantity of wine is to be poured out, the following procedure is used. The inflatable tube 19 is rotated in a direction opposite to that for squeezing the neck 18, so that the torsion in the area 22 decreases and finally the passage through the neck 18 is released. The air accummulated in the balloon will escape to the atmosphere, after which the empty balloon of strongly reduced volume can be easily pulled outwardly through the access tube 15 at the inflatable tube 19: the stock of wine is accessible via the access tube 15, which can be used as pouring member After pouring out the desired quantity of wine, the balloon 17 is again pushed through the access opening 15 into the vessel 1 and inflated again via the inflatable tube 19. The air expelled thereby from the vessel 1 will escape to the atmosphere via the access tube 15 and via vent holes 21 especially provided for the purpose in the cover.

[0041] Finally, the inflatable tube 19 is again rotated until, through torsion in the area 22, the passage through the inflatable neck 18 is shut off.

[0042] In the storage box usable as metering apparatus for coffee, as shown in Fig. 3, the cylindrical box 1 is closable by cover 2. The reservoir 9 for the flavour extract is mounted against the inside of the cover 2.

[0043] At the bottom end in the container there is installed a funnel 25 with its upper edge all around against the inner wall of the box.-: The outlet opening 32 of the funnel is connected to a metering member. This metering member comprises two horizontally positioned cylinders of different diameters, the smaller diameter cylinder 33 being provided with sliding fit and rotatably in the larger diameter. cylinder 34.

[0044] The outer cylinder, i.e. the larger diameter cylinder 34, with an upper passage in the wall thereof situated opposite the outlet opening of the funnel, is fixedly connected thereto. At the other end opposite the upper passage, there is provided a second or lower passage in the wall of the cylinder 34.

[0045] In the wall of the inner, smaller diameter cylinder 33 there is also provided a passage in a place corresponding with the passages of the outer cylinder in such a manner that the passage of the inner cylinder, by rotation thereof about its horizontal longitudinal axis, can be placed opposite the upper passage or opposite the lower passage. In the first-mentioned position, the inner cylinder can be filled with coffee and is therefore in the filling position, whereas in the last-mentioned position - the unloading position - the coffee present in the inner cylinder can again be discharged in a subjacent receptacle 27 and be further processed.

[0046] The operating rod 35 is connected fixedly with the one end thereof via an opening in the head face of the outer cylinder 34 to the head face of the inner cylinder 33. The other end of the operating rod 35 projects outwardly via an opening in the wall of the bottom chamber 29 connected to the box 1 and within which there are provided a gate composed of cylinders 33 and 34 and the receptacle 27, and is fitted with knob 36. The operating rod 35 can be rotated by means of the knob 36 and through the operating rod, the inner cylinder 33 from the filling position to the unloading position and vice versa.

[0047] The filling of the box 1 with coffee can take place after cover 2 has been detached. During the entire process of the portion-wise withdrawal of coffee from the box via the metering member the cover remains closed.

[0048] The filling position and the unloading position can roughly be found by paying attention to the corresponding marks provided for the purpose on the knob 36, which can subsequently be exactly found via the spring-loaded warning mechanism 30.

[0049] Through the funnel 25 there is obtained a properly guided flow of coffee in the direction of the cylinders 33 and 34 associated with the gate. On the other end, a proper supply of coffee to the funnel is achieved by rotation of the agitator rod 23, which projects outwardly via guide bush 8 in the cover 2, and is provided with knob 24 and adjacent the other end of which there is provided a scraper blade 31 whose form of contour corresponds with that of an axial cross-section of the funnel 25.

[0050] The volume of the inner cylinder 33 can be chosen in such a manner that it corresponds with a dosage suitable e.g. for two cups of coffee.

[0051] The metering member shown in Fig. 4 differs from the metering member in the storage box shown in Fig. 3 in particular in that the connecting chamber associated with the gate is horizontally rotatable about the axis of the box as axis of rotation.

[0052] In the metering member shown in Fig. 4, 40 represents a scraper having four blades 41'(Fig. 5). Said scraper blades are arranged around central shaft 39 and, tangentially contacting the central shaft, are fixedly connected thereto so as to be right-angled to each other, in successive relationship. Upon rotation of the scraper, the scraper blades move closely over the bottom of the funnel 42, with 45 being the funnel opening.

[0053] The annular connecting chamber 45 is divided into four quadrants by two right-angled partitions, the volume of each of the quadrant chambers being chosen in such a manner that it corresponds with a quantity of coffee for e.g. two cups.

[0054] The connecting chamber 45 is rotatable about the axis of the apparatus as axis of rotation. The rotation is effected by means of the operating handle 44, having the form of a ring with ring opening 50 to which a handle 49 is attached, with the diameter of the ring opening 50 being chosen in such a manner that the connecting chamber fits precisely therein.

[0055] The rotation of the connecting chamber 45 by means of the operating handle 44 takes place in steps, while the manner of coupling between the ring of the operating handle 44 and the connecting chamber is such that while the connecting chamber - step-wise - rotates always in the same direction, the operating handle is reciprocated per each rotation step between two stops. At each step, the connecting chamber is rotated through such an angle that the quadrant chamber of the connecting chamber, filled with coffee, disposed underneath the funnel opening 43, is brought from that position at the end of the rotation step above the unloading opening 48 of the bottom chamber 46 and is discharged in the receptacle 47 pushed into the bottom chamber 46. At the end of the rotation step an empty quadrant chamber has simultaneously occupied the place of the filled quadrant chamber just moved away from underneath the funnel opening 43. By operation of the operating handle 44, the scraper 40 is rotated simultaneously and by means of the scraper blades 41, ground coffee is pushed towards the funnel opening 43, thus filling the empty quadrant chamber with the coffee. Subsequently, a new operating cycle can be initiated by means of the handle 44.

[0056] Since the scraper 40 is driven through the operating handle 44, and not through an agitator rod passed through the cover, it is possible, upon application of the metering member shown in Fig. 4, to install a follower in the container without additional provisions. This follower is of the type which, through gravity, automatically moves with the level of the coffee stored in the container. In the simplest case, it concerns a follower whose outer diameter is just smaller than the internal diameter of the container. Such a follower can indeed also be used in combination with the storage box shown in Fig. 3, be it that allowance should then be made for the presence of the agitator rod.

[0057] The follower 51 shown in Fig. 6 can be employed as such as separate guard member in a storage box without cover for storing one of the earlier mentioned materials, e.g. coffee or (cut) tobacco.

[0058] The follower 51 is composed of a first plate 52 and a second plate 53 which, centred, can be clamped onto one another by means of the nut-and-bolt connection 54/55. Along the circumference of and between the first and second plates 52,53, there is provided an endless rubber hose 56. In the position shown in Fig. 5, no clamping pressure is exerted by the plates. Upon tightening the nut-and-bolt connection 54/55, the plates move towards one another and the rubber hose 56 is flattened. The outer circumference of the hose is thereby displaced further outwardly and the hose is pressed against the inner wall of the box, so that the position of the follower is then fixed.

[0059] For the purpose of application in a box with cover, the nut-and-bolt connection 54/55 can be received in a rod construction analogous to the rod construction 3 in Fig. 1, so that the follower 51 can be operated also externally.

[0060] The follower shown in Fig. 7 offers the same possibilities as the follower shown in Fig. 6 and is likewise composed of a first plate 62 and a second plate 63 wherebetween there is provided circumferentially a ring 66. The ring is retained in position by the retaining stops 65,67. When the plates 62 and 63 are clamped onto one another by means of the knob 64, the ring 66, through its sectional shape, buckles in the central portion thereof in outward direction and is pressed along the circumference against the inner wall of the box.

[0061] Naturally, modifications can be made in the apparatus according to the invention, as described in the above and as explained in the drawings, without departing from the scope of the invention.

Claims

1. A method of storing a material other than gaseous in shut-off condition in a container, said material having a quality decreasing as a result of exposure to the atmos- ophere, in which the material is brought into the container, the container is shut off and the material is subsequently withdrawn in a number of stages portion-wise from the container, while in the periods between the withdrawal of the material from the container, the remaining material is kept in shut off condition in the container, characterized in that at least during the periods between the withdrawal of the material from the container, said material is prevented from interacting with the air column in the container.

2. An apparatus for performing the method according to claim 1, comprising a hollow container, fitted with a sidewall closed all around, a closed bottom end and an open top end, characterized in that the apparatus comprises a follower to be installed in the container as a guard member with which the container can be practically shut off in a cross-section thereof, while the follower is movable with the level of the material available in the container, and furthermore being provided with fixing means through which the position of the follower can be fixed or be removed.

3. An apparatus according to claim 2, characterized in that the follower can be placed and fixed at an adjustable pressure against the material surface through the fixing means for confining the material under pressure between the bottom of the container and the follower.

4. An apparatus according to claims 2-3, wherein the hollow container is formed as a straight cylinder, characterized in that the follower is designed as a piston and the fixing means is a sealing cup projecting all around beyond the circumference of the follower, the outer circumference of said cup being larger than the inner circumference of the container wall.

5. An apparatus according to claim 4, characterized in that the sealing cup forms part of a plate or ring and the piston-like follower is right-angled to the axis thereof and is divided, and furthermore being provided with clamping means through which the plate or ring can be clamped between the follower portions.

6. An apparatus according to claim 4, characterized in that the sealing cup forms part of endless hollow hose of flexible material, which hose can be clamped with the clamping means between the follower portions along the edges thereof, having an outer circumference which is extendable by the clamping pressure between the follower portions to a length larger than the inner circumference of the container wall.

7. An apparatus according to claim 5,characterized in that the axial cross-section of the ring wall,viewsd in the direction of the axis of the ring, is plano-concave.

8. An apparatus according to claims 4-7, likewise comprising a cover, the cover and the container being fitted with members to be brought in coaction with each other through which the open top end of the container can be closed or released by the cover, characterized in that the follower, at the end facing away from the material to be stored in the container, is connected to a rod conducted via an opening in the cover through the cover in a manner movable within the opening.

9. An apparatus according to claim 8, characterized in that the fixing means are operable by means of the rod.

10. An apparatus according to claim 8, wherein the cover is thickened at the end facing the bottom, characterized in that the bottom of the container is replaced by the follower.

1 1. An apparatus according to claim 10, characterized by a second cover with which the bottom end of the container can be shut off and opened.

1 2. An apparatus according to claim 2, characterized in that the follower to be installed in the container is composed of an inflatable balloon whose neck is connected to a tube by means of which the balloon is inflatable from outside the container.

13. An apparatus for performing the method according to claim 1, comprising a hollow container fitted with a sidewall closed all around, a closed bottom end, an open top end and a guard member, in particular a cover with which the open connection of the container with the atmosphere can be shut off or released, characterized in that the container is provided or not with a follower movable automatically, through gravity, with the level of the material available in the container and that there is provided in the bottom of the container an opening which is blocked'off by a gate from an open communication with the atmosphere.

14. An apparatus according to claim 13 with cylindrical container, characterized by an externally operable scraper member, comprising a rod conducted via an opening in the cover through the cover in a manner rotatable within the opening, said rod being fitted at the portion extendable into the container with one or more scraper blades; the connecting chamber of the gate is rotatable about the axis of the container as axis of rotation and is divided into a plurality of sub-chambers of substantially identical volume; operating means with which the connecting chamber is rotatable between a loading position or an unloading position, as well as a receptacle wherein the material can be discharged in the unloading position of the connecting chamber.

15. An apparatus according to claim 14, characterized in that the scraper comprises four scraper blades spaced about a central shaft and, tangentially contacting the central shaft, are affixed thereto, with the scraper blades being spaced about the shaft extending at right angles to each other.

16. An apparatus according to claims 2-11 and claims 13-16, characterized in that the apparatus likewise contains an air-condition member, comprising a reservoir whether or not provided with an absorbing material, said reservoir being furthermore fitted with means for controlled delivery of volatile materials stored in the reservoir to the surroundings.

17. A follower fitted with fixing means suitable for application in the container associated with the apparatus according to claims 2-7.

Drawing