Barrel follow plate with spindle pump

Description

[0001] The present invention relates to a device for removing a pasty mass from a barrel.

[0002] It is a well-known process engineering task, for example in plastics production and processing, to pump viscous materials that are filled into cylindrical containers or barrels, usually made of sheet metal or plastic, for storage, transport and direct removal during a dosing process, from the barrels during further processing.

[0003] So-called "drum follower plates" are used. The feed pumps can be mounted on them. These follower plates are assemblies with cylindrical rings or plates that retract into the drum with a seal, with sealing rings sealing the assembly to the drum wall. They are inserted into the drum (after removing the actual drum lid) and are equipped with sealing rings that completely seal the drum follower plate to the drum wall. Thus, they form a hermetically sealed, rigid cover over the liquid and, together with the drum, completely and tightly enclose the liquid. The drum follower plates are then actively pressed (guided and driven) onto the material. In other known processes, they slide downwards under their own weight or due to negative pressure when the material is removed.For this purpose, the containers used in this context are usually barrels whose interior has a cylindrical, in particular circular-cylindrical, inner contour (possibly with stiffening longitudinal or circumferential beads), whereby the inner contour usually opens outwards without tapering into an outer opening of the interior, namely into the barrel opening.

[0004] A plastic mass for creative modeling is so-called clay.

[0005] 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 for this purpose.

[0006] Clay is a plastically deformable mass, usually wax-based, at certain temperatures. 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 shape, especially for the designer to check it during modeling.

[0007] For example, before the market launch of a new car, the design process for its new body is lengthy and complex: sketches, drawings, and 3D CAD are used first. 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 truly assessed both as a whole and in detail. The shapes and proportions of the clay model can also be finely and precisely 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, whereby the clay is heated, for example, 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 and forms a substantially homogeneous bond with clay material of approximately the same temperature that is applied on top. Once cooled, the area supplemented by the application regains its shape, forming a substantially homogeneous transition area with careful processing. Clay can also be painted using well-known processes or covered with colored foils. In this way, a model can be created from clay that is extremely close to, or even identical to, the intended product in terms of shape and surface.

[0008] 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 - usually in layers to create a desired clay layer thickness - and thus to form a preliminary model, if possible at least the size of the final model everywhere.

[0009] 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, within the aforementioned temperature range of the clay, in which it can be plastically deformed and thus adheres well to the frame panels. Various known measures exist for improving adhesion, such as applying a sealant (e.g., as a paint or spray), particularly to bind 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.

[0010] 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 part, by plastic shaping or at least prepared by appropriate pre-shaping and contouring.

[0011] However, mechanical devices and methods are also known, for example, from DE 10 2016 109 816. Here, clay is plasticized using an extruder and conveyed through a hose, where it is then applied by an application head – guided manually or robotically. A device according to the preamble of claim 1 is known from EP 1 897 849 A1.

[0012] The current state of the art presents difficulties in mechanical processing using such a device: handling clay ingots when feeding them into such an extruder is a technical challenge. Clay pieces, such as chips, have been tested as an alternative, but they require a corresponding preliminary crushing step because clay is regularly produced and traded in ingots.

[0013] The present invention is based on the object of creating a device for the mechanical conveying of clay, in particular for the production of models, which simplify and accelerate model making using clay as a molding material.

[0014] This object is achieved by a device having the features of claim 1. Preferred embodiments are specified in the subclaims.

[0015] The device according to the invention serves for removing clay or another pasty mass from a barrel with a cylindrical inner contour. For this purpose, it is equipped with a barrel follower plate assembly (in particular a so-called barrel follower plate) adapted to seal an opening of a barrel in a vacuum-tight manner. The device according to the invention has a pump configured to pump mass from the barrel, into which the barrel follower plate assembly is inserted, from the bottom thereof (in the intended arrangement) through a line connection into a connecting device. The connecting device is arranged on the outside or (in the intended arrangement) top side of the barrel follower plate assembly and is configured for connecting a clay conveying hose.

[0016] According to the invention, the pump is a spindle pump according to the characterizing part of claim 1.

[0017] According to the invention, this makes it possible to draw even extremely viscous, almost non-flowable substances or masses such as clay into the pump and then to convey them through the pump, in that the non-enclosed area of ​​the conveying spindle is in direct contact with the conveyed material, particularly over as large an area as possible and with the conveying groove immersed in the latter.

[0018] The pump has (at least) two such feed screws, which are then preferably all arranged parallel to one another. The pump has a drive screw arranged parallel to the at least one feed screw and has (at least) one helical drive tooth that meshes with the feed groove of the at least one feed screw.

[0019] It is furthermore particularly preferred that the underside of the follower plate has a heating device in order to heat the conveyed material at least in the region of contact with the at least one conveying spindle and thus to make it at least somewhat less viscous.

[0020] It is also particularly preferred that the interior of the barrel to which the device is adapted (in particular a smooth-walled cylindrical steel sheet lidded barrel with a clamping ring closure or a cylindrical plastic container) has a cylindrical inner contour, and that the barrel follower plate assembly has a follower plate with a seal which is arranged on a circumference of the follower plate and is adapted to be inserted into the cylindrical inner contour of the barrel in a circumferentially sealing manner, and that the follower plate assembly is adapted to be guided and driven by a drive so as to be movable translationally vertically downwards in the direction of the cylinder axis of the barrel oriented in such a way that the follower plate can be lowered downwards in the direction of the cylinder axis to a liquid level (of the mass in the barrel) or has the drive which guides and drives the follower plate so as to be movable translationally vertically downwards in the direction of the cylinder axis of the barrel oriented in such a way that the follower plate can be lowered downwards in the direction of the cylinder axis to a liquid level (of the mass in the barrel).

[0021] The device according to the invention can also comprise an evacuation device, in particular with an evacuation pump, and be operated in conjunction with the latter. For example, the follower plate then also comprises a connection device arranged on the outside or top of the barrel follower plate assembly and configured for connecting an evacuation pump. This evacuation pump or vacuum pump can be used to place the interior of the barrel under the greatest possible negative pressure (a so-called vacuum). This can cause air pockets in the liquid to be sucked out (particularly during refilling of the barrel), and the stronger the negative pressure, the more completely this effect will be.

[0022] The drum follower plate can then be controlled and slowly lowered under the "vacuum" that can be created by the evacuation device on the underside of the follower plate, finally resting on the liquid surface. This prevents disruptions in the subsequent extraction process caused by air between the surface of the mass or clay and the drum follower plate. The feed pump according to the invention (which is located in particular on the follower plate) is now filled by pressing the follower plate onto the material (using pneumatic or hydraulic cylinders or electrical units). Material is pressed into the at least one feed groove of the at least one feed pump – and this occurs without air pockets, because the space above the liquid (through which the follower plate is lowered) is evacuated before and during the lowering process, thus preventing air from entering the feed pump.

[0023] These and other advantages and features of the invention are further described with reference to the following figures of an embodiment of the invention. Figure 1 shows a cross section through a device according to the invention and Figure 2 shows a bottom view of the device according to the invention from Figure 1 .

[0024] The figures show a device 2 for removing clay 4 from a barrel 6 with a cylindrical inner contour. For this purpose, it is equipped with a barrel follower plate 8, which is adapted to close an opening of a barrel 6 in a vacuum-tight manner. The device 2 has a pump 10, which is configured to pump clay 4 from the barrel 6, into which the barrel follower plate 8 is inserted as shown, from its underside 12 (in the intended arrangement shown), i.e. from inside the barrel 6, through a line connection 14 into a connecting device (not shown). The connecting device is arranged on the outer side 16 of the barrel follower plate 8 and is configured to connect a clay conveying hose (not shown) in order to apply the clay 4 therethrough onto a surface of an automobile model blank (not shown).

[0025] The pump 10 is a spindle pump with two parallel delivery screws 18, each having a helical delivery groove 20. The pump 10 also has a drive spindle 22, which is arranged in a plane parallel to the two delivery screws 18 and has a similarly helical drive tooth 24 with the same helical pitch. The drive tooth 24 of the drive spindle 22 meshes with the delivery groove of each of the two delivery screws 18.

[0026] The two conveyor spindles 18 have an unenclosed outer surface 26 for conveying the clay 4 out of the barrel 6, each in an area 26 accessible from the underside 12 of the barrel follower plate 8. The two conveyor spindles 18 protrude downward from the underside 12 of the barrel follower plate 8 with their lower, unenclosed end 26.

[0027] This makes it possible according to the invention to draw even extremely viscous, almost non-flowable materials or even the plastic masses 4 described above, and in particular clay 4, into the pump 10 and then to convey them through the pump 10. The unenclosed area 26 of the two conveyor spindles 18, in the embodiment shown, their unenclosed lower end 26, is immersed over a large area in the conveyed material 4 and is in direct contact with it, so that the conveying groove 20 comes into direct contact with the clay 6 over the length of the unenclosed area. Under the pressure in the drum 6, built up by the driven drum follower plate 8, clay 4 is pressed into the conveying groove 20 and conveyed upwards (through an otherwise enclosed area 28 of the conveyor spindles 18) into the line connection 14, which leads through the follower plate 8 to the outside of the drum 6 for further transport (not shown).

[0028] It is particularly preferred that the underside 12 of the follower plate 8 has a heating device 30 with star-shaped arranged heating fins 32 in order to immerse into the conveyed material 4 and to heat it at least in the area surrounding the lower non-housed ends 26 of the conveyor spindle 18 and thus to make it at least somewhat less viscous. Reference symbol

[0029] Device 2 for removing clay 4 Barrel 6 with cylindrical inner contour Barrel follower plate 8 Pump 10 Underside 12 of the barrel follower plate 8 Line connection 14 into a connection device (not shown) Outside 16 of the barrel follower plate 8 Conveyor spindles 18 Helical conveyor groove 20 Drive spindle 22 Helical drive tooth 24 Shell surface area 26 of the conveyor spindles 18, not enclosed and accessible on the underside 12 of the barrel follower plate 8; lower, unenclosed end 26 of the conveyor spindles 18 Enclosed area 28 of the conveyor spindles 18 Heating device 30 Heating fins 32

Claims

1. A device (2) for withdrawing clay (4) or another pasty mass from a barrel (6) having a cylindrical inner contour, comprising a barrel follower plate assembly adapted to seal an opening of a barrel in a negative-pressure-tight way, comprising a pump (10) adapted to pump mass from the bottom side (12) of said barrel follower plate assembly through a line connection (14) into a connecting device that is provided on the outside of said barrel follower plate assembly, wherein said pump (10) is a spindle pump, characterized in that said spindle pump (10) includes at least two conveying spindles (18) that have (at least) one helical conveying groove (20) and are provided parallel to another, and - which have a non-encased lateral surface (26) in a region that is accessible from the bottom side (12), and / or - which protrude downwards in a non-encased manner from the bottom side (12) of said barrel follower plate assembly, and comprising a driving spindle (22) provided between the two conveying spindles (18) in a plane and having a similarly helical driving tooth (24) that meshes with the conveying groove of each of the two conveying spindles (18) with the same helical pitch.

2. The device (2) according to the preceding claim, characterized in that said pump (10) has a driving spindle (22) that is provided in parallel with said at least one conveying spindle (18) and has (at least) one helical driving tooth (24) that meshes with the conveying groove (20) of said at least one conveying spindle (18).

3. The device (2) according to any of the preceding claims, characterized in that said bottom side (12) has a heating device (30).

4. The device (2) according to any of the preceding claims, characterized in that the interior space of said barrel (6), to which the device (2) has been matched, has a cylindrical inner contour, and that said barrel follower plate assembly has a follower plate (8) having a seal provided on the circumference of said follower plate (8) and being adapted for insertion into the cylindrical inner contour of the barrel (6) in a circumferentially sealing manner, and that said barrel follower plate assembly - is adapted for being guided and driven by a drive vertically downward in the direction of the cylinder's axis of the thus oriented barrel (6) moveably in such a way that the follower plate (8) can be lowered in the direction of the cylinder's axis downward to a liquid level (of the mass in the barrel (6)), or - has a drive that guides and drives the follower plate (8) translationally vertically downward in the direction of the cylinder's axis of the thus oriented barrel (6) moveably in such a way that the follower plate (8) can be lowered in the direction of the cylinder's axis downward to a liquid level (of the mass in the barrel (6)).