Method for filling a cylindrical container with clay and a packaging unit of such a container filled with clay

Abstract

The invention discloses a method for filling a container of standardised geometry with clay, having the steps of: d) extruding the clay by means of an extruder, e) using a pump and / or the pressure built up in the clay by the extruder to pump the clay plasticised by the extruder from the extruder outlet through a conduit into an outlet opening on the underside of a piston element that is adapted to fit through an opening in the container and into its interior, which is substantially cylindrical with an interior cross-section and an opening cross-section which remain substantially constant along the cylinder axis, f) guiding the piston element in the direction of the cylindrical axis by means of a device with a drive system which is designed to exert pressure against the clay introduced under the piston element into the container.

Description

[0001] Method for filling a cylindrical container with clay and packaging unit of such a container filled with clay

[0002] The present invention relates to a method for filling a container and to such a container filled with clay.

[0003] A plastic mass for creative modeling is so-called clay.

[0004] Clay is a material used primarily for model making in automotive design. Character designers (for example, for films, cartoons, and video games), industrial designers, artists, and architects also use this material to model their three-dimensional designs. It is a special development of the well-known plasticine.

[0005] Clay is a typically wax-based mass that can be molded plastically at certain temperatures (usually above room temperature). Sulfur is used as a filler in most types. Clay is usually brownish or gray in color, which allows for easy visualization of a modeled form, especially for the designer to check it during modeling.

[0006] For example, before the market launch of a new car, the process of designing its new body is lengthy and complex: sketches, drawings, and 3D CAD models are created. But even today, models of the vehicle are ultimately built, usually in various scales from 1:10 and 1:4 to 1:1. Only then can the shapes and proportions be properly assessed both as a whole and in detail. The shapes and proportions of the clay model can also be finely and accurately reworked and finished. Because clay, with its high dimensional stability at room temperature, can be milled, planed, carved, or sanded, for example. Subsequent material application is also possible; for example, the clay is heated in the area of ​​the planned material application using a hot air blower or heat lamps (to temperatures no higher than in the double-digit Celsius range).In this upper temperature limit, particularly around 60 to 70°C, clay can be plastically deformed – without, however, becoming liquid or even flowing in a pasty manner – and forms an essentially homogeneous bond with clay material of approximately the same temperature that is additionally applied. Once cooled, the area supplemented by the application regains its shape, with an essentially homogeneous transition point if carefully processed, and can be reworked there, including by removal. Clay can also be painted using familiar processing steps. In this way, a model can be produced from clay that is extremely close to, or even identical to, the planned product in terms of shape and surface.

[0007] For such a model, a wooden or metal frame is usually first made, onto which panels (e.g. foam panels) made of polyurethane, for example, are attached, onto which clay is applied as the outer layer of the model, which can be modeled as described - to create a desired clay layer thickness, usually again in layers - and thus to form a preliminary model, if possible at least the size of the final model everywhere.

[0008] This application is still widely done by hand. Typically, the warmed clay (below 60°C) is applied with kneading hand movements and worked with spatula-like tools and blades – specifically in the aforementioned temperature range of the clay, in which it can be plastically deformed and thus adheres well to the frame plates. Various known measures exist to improve adhesion, such as applying a sealant (for example, as a paint or spray, especially for binding dust), and / or creating depressions and / or barbed structures, for example, by drilling holes or milling grooves, in which the clay can then adhere in a form-fitting manner.During and after this application, as long as the clay has not yet completely cooled down, the desired surface shape of the clay can also be created, at least in some areas, by plastic shaping or at least prepared by appropriate pre-shaping and contouring.

[0009] Devices for mechanically applying clay are now being developed on a widespread basis. Due to the significantly higher throughput of clay in this processing, it is advantageous to provide the clay not exclusively in the form of bars or rods, as has previously been the case, but in larger (and transportable) packaging units. Attempts have already been made to process clay from a barrel in this way. However, for this experimental process, the barrel was filled with clay by hand, because clay, as a plastic mass, cannot be pumped like a liquid using conventional methods.

[0010] The present invention is based on the object of providing clay in larger packaging units of reproducible quality and as free as possible from air inclusions. This object is achieved by a method having the features of claim 1 and by a product having the features of claim 10. According to the invention, there is a method for filling containers of standardized geometry (containers with essentially the same geometry) with clay, as well as a container filled with clay in this inventive manner.

[0011] According to the invention, the container to which the method according to the invention is applied has an opening and a substantially cylindrical interior with a cross-section that is substantially constant along the axis of the cylindrical shape, not only of the interior but also of the opening.

[0012] The method according to the invention comprises the steps of: a) extruding the clay by means of an extruder, b) pumping the clay plasticized by means of the extruder by means of a pump and / or by means of the outlet pressure built up in the clay by means of the extruder through a line into an outlet opening on the underside of a piston element which is adapted to fit through the opening of the container and into its interior, c) guiding the piston element in the direction of the cylinder axis by means of a device with a drive which is designed to exert pressure against the clay introduced under the piston element into the container.

[0013] An extruder is a device used in plastics processing that conveys, compacts, and extrudes plastically deformable masses using (at least) one screw. Initially developed for rubber processing, it has become widespread in the field of thermoplastics and now even for pasty food products. In a screw extruder, the varying geometry of the thread cross-section along the length of the extruder screw causes transport, compression, degassing, mixing, and homogenization of the material being processed in the extruder. According to the invention, however, an extruder is used to "knead" the clay and thus heat it, plasticize it, homogenize it, and, if necessary, degas it—in other words, make it pumpable—and to convey it under pressure into a pump and from there (or even, especially without a pump, only through the pressure built up in the clay by the extruder) through the line.The clay may be in the extruder during a process step, particularly the final one, of its production; however, it may also be fed into the extruder (i.e., particularly from intermediate storage, for example, in a known rod or ingot form) specifically for filling into the container according to the invention. Pre-processing steps, such as, for example, comminution and / or heating, are advantageously possible for this purpose.

[0014] The clay is then conveyed according to the invention into an outlet opening on the underside of a "piston element". This piston element is adapted according to the invention to fit through the opening of the container for which the invention is designed, namely in the sense of a cylindrical container already described, as well as into its interior:

[0015] When withdrawing high-viscosity liquids from cylindrical barrels in plastics processing, so-called "barrel follower plates" are used, particularly to prevent the pumping of air pockets. Such barrel follower plates, for example, are "piston elements" according to the invention, components according to the invention in the manner of a piston, which may fit through the cylinder opening into the barrel, i.e., into the cylindrical interior of the container, with a circumferential piston seal, whereby sealing rings can seal the assembly to the barrel wall. They are inserted into the barrel (after removal of the actual barrel lid) and may be provided with sealing rings that can completely seal the barrel follower plate to the barrel wall. Thus, they form a hermetically sealed, rigid cover over the liquid and, together with the barrel or container, completely and tightly enclose the liquid.During plastics processing, the drum follower plates are then actively pressed (guided and driven) onto the material. In known processes, they slide downwards under their own weight or under negative pressure when the material is removed. For this purpose, the containers used in this context are drums, whose interior has a substantially cylindrical, in particular circular-cylindrical, inner contour (possibly, for example, with stiffening longitudinal or circumferential beads or other deviations from the mathematical cylindrical shape, which do not conflict with this technical principle according to the invention), with the inner contour, again essentially, opening outwards into an outer opening of the interior, namely the drum opening, without any taper.According to the invention, however, the piston element is used to prevent air pockets (not during removal, but rather) during filling of the container by the inventive step c): Preferably, using a pneumatic cylinder as the drive, the piston element is guided in the direction of the cylinder axis of the container interior by means of a device with a linear drive. These are designed to exert pressure against the clay introduced into the container under the piston element.

[0016] According to the invention, the piston element can be adapted to the geometry of the container such that, in step c), an annular gap exists between the piston element and the inner surface of the cylinder jacket of the container. The annular gap can then be sealed with a seal, or it can serve for venting without a seal. Particularly (but not exclusively) with a seal, however, negative pressure can be created in the container and / or beneath the piston element using a vacuum pump for venting.

[0017] According to the invention, conveying the clay into the outlet opening on the underside of the piston element is possible using a twin arrangement: A switch in the supply line to the piston element leads into a second such supply line and to a second such piston element along with the drive device. Thus, according to the invention, a first container can be filled through the first supply line and by means of the first piston element, while in the vicinity of the second piston element, the filled container is removed, sealed, and transported further. To prepare for the next filling, a next container is then inserted into this second piston element for filling.This means that immediately after the filling of the container through the first supply line and the first piston element has been completed, the switch can be "switched" and the filling of the container already prepared there can begin through the second piston element, without having to wait for the removal of the filled container and the insertion of a new container to be filled in the vicinity of the first piston element.

[0018] The line between the pump and the piston element can have a (particularly rigid) pipe section in which a static and / or a dynamic mixer is arranged:

[0019] The mixing of fluid components, for example in the production of plastics, before introducing the plastic into the sprue of a casting mold or, for example, before applying it to a fiber fabric or woven fabric for the production of GRP or CFRP, is generally carried out using a tubular passage (mixer) with shaped elements (turbulence elements) in its interior, which variously redirect, deflect, locally dammed, create turbulence and / or swirl the fluid flowing through, and thus mix it. As is well known, feed lines lead into this mixer, particularly in quantities corresponding to the number of fluid components from which the plastic is to be mixed. For particularly uniform, thorough mixing of the components, it has proven advantageous and established practice to arrange the turbulence elements in the tubular passage not just in a fixed manner (static mixer), but in a rotating design (dynamic mixer).Known devices for mixing at least two fluid components by means of dynamic mixers then have at least two component feed lines and a rotary drive with a drive shaft, and the device is then adapted to place a tubular feed element in fluid-tight line connection with the component feed lines, and to place the drive shaft in rotary drive connection with the mixer insert by means of a rotary drive connection structure of a mixer insert (which has a support rod element with at least one swirling element and which is adapted for insertion into the feed element) when the mixer insert is inserted into the feed element and the feed element is placed in the line connection with the component feed lines.Such a rotary drive connection structure on known mixer inserts is generally an opening lying essentially radially to the axis of rotation, into which a hook at the end of the drive shaft is hooked to establish the drive connection. The mixer insert and the feed-through element can (also according to the invention) be single-use or disposable items. According to the invention, however, these (static or dynamic) mixers preferably do not serve to mix components, but rather additionally shear and / or homogenize the clay that has been plasticized to flow according to the invention. This prevents, for example, visual changes to the clay and a reduction in its quality due to demixing, for example in the form of streaking. The clay can also be sheared, for example by means of a device with a (static or dynamic) mixer, for example between the extruder and the pump.

[0020] In order to adjust the plasticity and thus the flowability of the clay in the extruder, pressure in the clay can be measured in the area of ​​the extruder outlet and the pump inlet, the pressure difference can be calculated by a computer, and the pressure in the extruder can be regulated using a control system. For this purpose, the control system can adjust the pump speed using this pressure difference - i.e. with the pressure difference as the controlled variable and the pump speed as the manipulated variable. To improve the flowability of the clay, the pump and / or a flange between the extruder and the pump and / or the line and / or the pipe section can be heated at least in sections and / or the piston plate and / or the base of the container and / or its outer surface can be heated at least in certain areas using a heating device.

[0021] In order to be able to check the condition of the clay, namely after the extruder, before and / or after the pump, if necessary before and / or after the mixer, and / or before the piston element, a line branch can be provided there (for example also from a bypass for this purpose), through which clay can be taken as a sample.

[0022] The pump is preferably a screw pump, which is suitable for pumping very high viscosity liquids (which Clay does not belong to), but possibly also a gear or piston pump.

[0023] These and other advantages and features of the invention are further described with reference to the following figure of an embodiment of the invention.

[0024] Figure is a schematic representation of a device for carrying out the method according to the invention.

[0025] The figure shows a method for filling a container 2 of standardized cylindrical geometry (namely in particular a barrel 2) with clay 4.

[0026] As can be seen, the container 2 has an opening 6 and a cylindrical interior 8 with a cross-section that remains constant along the cylinder axis 10 (the cylindrical shape) - not only of the interior 8, but also of the opening

[0027] The method shown comprises the steps of: a) extruding the clay 4 by means of an extruder 12, b) pumping the clay 4 plasticized and pressurized by means of the extruder 12 by means of a pump 14 through a line 16 into an outlet opening 18 on the underside of a piston element 20 which is adapted to fit through the opening 6 of the container 2 and into its cylindrical interior 8, c) guiding the piston element 20 in the direction of the cylinder axis 10 by means of a device 22 with a drive 24 which is designed to exert pressure against the clay 4 introduced under the piston element 20 into the container 2.

[0028] The extruder 12 is a device that conveys, compacts, and expels the clay 4 by means of a screw 26. The varying geometry of the thread cross-section along the length of the extruder screw 26 effects transport, compression, degassing, mixing, and homogenization of the clay 4 processed in the extruder 12. The clay 4 is in the extruder 12 in a final process step of its production (including, in particular, the mixing of its primary components (not shown), mixing, and homogenization - possibly also in other devices (not shown) in the line upstream of the extruder 12). Here, the extruder 12 is further used to "knead" the clay 4 and thus to heat it, plasticize it, homogenize it, degas it - thus making it pumpable, so to speak - and to convey it under pressure into the pump 14, a screw spindle pump 14, and from there through the line 16.

[0029] The clay 4 is then conveyed into the outlet opening 18 on the underside of the "piston element" 20. This, a so-called barrel follower plate 20, is adapted to fit through the opening 6 of the container 2, onto which the piston element 20 is thus arranged, as well as into its interior 8.

[0030] It is a piston-like component that, with a circumferential piston seal 26, fits through the cylinder opening 6 into the barrel 2, i.e., into the cylindrical interior 8. It is inserted into the barrel 2 (after removing the actual barrel lid - not shown). The seal 26 completely seals the barrel follower plate 20 to the barrel wall. Thus, the piston element 20 forms a hermetically sealed, rigid cover over the clay 4 in the barrel and, together with the barrel 2, completely and tightly encloses the clay 4. The barrel follower plate 20 is then actively pressed (guided and driven) onto the material 4.According to the invention, the piston element 20 is used to avoid air inclusions (not during removal, but) during filling of the container 2 by the above-mentioned step c): by means of a pneumatic cylinder as drive 24, the piston element 20 is guided in the direction of the cylinder axis 10 of the container interior 8 by means of a device 22 with linear bearings. These are configured to exert pressure against the clay 4 introduced into the container 2 under the piston element 20. For venting, a vacuum pump 28 also creates a vacuum in the container 2 under the piston element 22.

[0031] The line 16 between pump 14 and piston element 20 has a rigid pipe section 30 in which a (dynamic) mixer 34 is arranged, driven in rotation by a motor 32. Here, its swirling elements serve not so much to mix components, but also advantageously shear and / or homogenize the clay 4, which has been plasticized to flow according to the invention. This also prevents, for example, visual changes to the clay 4 and a reduction in its quality due to demixing, for example in the form of streaks. In order to adjust the plasticity and thus the flowability of the clay 4 in the extruder 12, pressure in the clay is measured in the area of ​​the extruder outlet 36 and the pump inlet 38. The pressure difference is calculated by an EDP 40 and the pressure in the extruder is regulated by a control system 40.

[0032] In order to further improve the flowability of the clay 4, the pump 14 and the line 16 and the pipe section 30 are tempered in sections and the piston plate 20 and the container 2 are tempered in regions by means of a heating device 42.

[0033] Reference numbers

[0034] Container, Barrel 2

[0035] Clay 4.

[0036] Container opening 6

[0037] Container interior 8

[0038] Cylinder axis 10

[0039] Extruder 12

[0040] Pump 14

[0041] Line 16

[0042] Outlet opening 18

[0043] Piston element 20

[0044] Linear guide device 22

[0045] Drive 24

[0046] Extruder screw 25

[0047] Piston seal 26

[0048] Vacuum pump 28

[0049] Pipe section 30

[0050] Engine 32

[0051] Dynamic Mixer 34

[0052] Extruder outlet 36

[0053] Pump inlet 38

[0054] IT and Control 40

[0055] Heating device 42

Claims

Claims 1. Method for filling a container (2) of standardized geometry with clay (4) comprising the steps of: a) extruding the clay (4) by means of an extruder (12), b) pumping (14) the clay (4) plasticized by means of the extruder (12) by means of a pump (14) and / or by means of the pressure built up in the clay (4) by means of the extruder (12) from the outlet of the extruder (12) through a line (16) into an outlet opening (18) on the underside of a piston element (20) which is adapted to fit through an opening of the container (2) and into its interior (8), which is essentially cylindrical with a cross-section of the interior (8) and the opening that remains essentially constant along the cylinder axis (10), c) guiding the piston element (20) in the direction of the cylinder axis (10) by means of a device with a drive (24), which is designed to exert pressure against the clay (4) introduced under the piston element (20) into the container (2).

2. Method according to claim 1, characterized in that the piston element (20) is adapted to the geometry of the container (2) such that in step c) there is an annular gap between the piston element (20) and the inner surface of the cylinder shell of the container (2).

3. Method according to claim 2, characterized in that the annular gap between the piston element (20) and the inner surface of the cylinder shell of the container (2) is sealed by a seal, or serves for venting without a seal.

4. Method according to claim 2, characterized in that the annular gap between the piston element (20) and the cylinder The inner surface of the container (2) is sealed by a gasket, and a vacuum is generated in the container (2) and / or under the piston element (20) for venting by means of a vacuum pump (28). A method according to one of the preceding claims, characterized in that the line (16) has a pipe section (30) in which a static and / or a dynamic mixer (34) is arranged. A method according to one of the preceding claims, characterized in that pressure in the clay (4) is measured at the extruder outlet (36) and at the pump inlet (38), and the pressure difference is calculated by a computer and the pressure in the extruder (12) is controlled by means of a control system with the pressure difference as the controlled variable and the pump speed as the manipulated variable.A method according to any one of the preceding claims, characterized in that, by means of a heating device (42), the pump (14) and / or a flange between the extruder (12) and the pump (14) and / or the line (16) and / or the pipe section (30) are at least sectionally heated and / or the piston plate and / or the bottom and / or the outer surface of the container (2) are at least area-wise heated. A method according to any one of the preceding claims, characterized in that the pump (14) is a screw pump. A method according to any one of the preceding claims, characterized in that the linear drive is a pneumatic cylinder. A cylindrical container (2) filled with clay (4) according to any one of the preceding claims.

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