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Abstract

The invention relates to a follower plate (10) for closing an upwardly open container for viscous material, which has a container bottom and a container wall extending upwards from the container bottom. The follower plate is movable towards the container bottom, resting against an inner surface of the container wall facing the interior of the container. The follower plate has a plate body (12) in which a material outlet for conveying the viscous material from the container and at least one vent opening (20) for venting air from the container are arranged. According to the invention, a valve seat (26) of a vent valve (24) is arranged in each vent opening (20), the seat being fixedly connected to the plate body (12).

Description

[0001] The invention relates to a follower plate for closing a container open at the top according to the preamble of claim 1.

[0002] A follower plate of the type mentioned above is known, for example, from DE 10 2020 127 440 A1. It is a component of a device for conveying viscous material from barrel-like, open-topped containers. To convey the material, the follower plate is inserted into a container from above and, resting on the surface of the material in the container, moves towards the bottom of the container, following the decreasing material level as the container is emptied, sealed against the inner surface of the container wall, until the container is emptied. Once the container is emptied, the follower plate is removed from it and inserted into another, full container. The follower plate has a plate body, the underside of which rests on the material in the container, and in which a material outlet is arranged, through which the material is conveyed from the barrel by means of a feed pump.To allow any air trapped between the surface of the material and the underside of the plate body to escape before the conveying process begins, at least one vent opening is provided in the plate body. Once the container is empty of air, the vent opening must be tightly closed to prevent viscous material from escaping and air from re-entering the container. For this purpose, each vent opening is equipped with a vent valve that can close and release the vent opening. A vacuum pump is usually also connected to the vent opening. DE 10 2017 215 706 A1 discloses a follower plate in which a valve seat is arranged in the plate body.

[0003] However, since small amounts of viscous material can enter the vent opening during venting, the vent valves must be regularly cleaned of contamination from the viscous material. This is a time-consuming process.

[0004] It is therefore an object of the invention to further develop a follower plate of the type mentioned at the outset in such a way that easier cleaning is possible.

[0005] This object is achieved according to the invention by a follower plate having the features of claim 1 and by the method according to claim 10. Advantageous developments of the invention are the subject of the dependent claims.

[0006] The invention is based on the idea of ​​integrating a valve seat into each vent opening and firmly connecting it to the plate body. The valve seat is therefore not part of a valve unit detachably mounted on the plate body, but an integral component of the plate body. It is preferred that each of the valve seats is pressed force-fittingly into the plate body so that it is held in the plate body by friction. Each of the valve seats is expediently made of a plastic so that it is both soft and inexpensive to manufacture. Contaminated valve seats can then be easily removed from the plate body using a machining process, in particular using a drilling tool. It is further preferred that each of the valve seats has a conical contact surface for a valve needle. This enables good sealing, in particular with a valve needle made of hard material.

[0007] To sealably close the at least one vent opening, it is expedient to provide that each vent opening is assigned a valve unit, which has a valve needle for closing the vent opening at its valve seat and an actuating device for moving the valve needle between a closed position, in which it sits sealingly on the valve seat accommodated in the vent opening, and an open position, in which it is lifted from the valve seat. Each valve unit expediently has a valve housing, through which a vent channel extends, opening into the respective vent opening, and from which the valve needle protrudes, at least in the closed position.In particular, it is preferred that the distance by which the valve needle protrudes from the valve housing in the closed position is at least one-third, preferably at least half the thickness of the plate body between its underside and an upper side on which the valve housing sits. The valve housing is then arranged at a distance from the valve seat so that it is less contaminated by the viscous material. The valve needle is expediently made of hard metal, which is very hard, chemically resistant and easy to clean. A hard metal is understood to be a metal matrix composite material in which hard materials in particle form are held together by a metal matrix. Metal carbides or metal nitrides, such as tungsten carbide, titanium carbide, titanium nitride, niobium carbide, tantalum carbide or vanadium carbide, are used as hard materials.In particular, each valve unit is detachably attached to the plate body, allowing it to be removed as a whole without damage. This allows the expensive components of the respective valve—namely, the valve needle, the valve housing, and the actuating mechanism—to be removed from the plate body and cleaned as a unit without great effort. The valve seat, however, which is designed as a cheap wear part, remains in the plate body and is removed from its vent opening, destroying it in the process.When servicing the follower plate, it is advisable to proceed as follows: each valve unit is removed from the plate body and cleaned if necessary, then each of the valve seats is removed from the vent opening containing it and replaced with a new valve seat, if necessary, and finally each of the valve units is removably attached to the plate body.

[0008] The invention is explained in more detail below using an exemplary embodiment schematically illustrated in the drawing. In the drawings: Fig. 1 a follower plate with connected container pump in perspective view; Fig. 2 a partial representation of the follower plate according to Fig. 1 on average; Fig. 3 a valve unit in perspective view and Fig. 4 the valve unit according to Fig. 3 on average.

[0009] The follower plate 10 shown in the drawing is used to convey viscous material such as an adhesive, a sealant, an insulating material or a thermal paste from a barrel-like container that is open at the top and not shown in the drawing. The follower plate 10 is inserted into the container via its upper, open side. It has a plate body 12 and presses the underside 14 of the plate body 12 onto the surface of the material contained in the container. The follower plate 10 also has two sealing and wiping rings 16 running around a lateral surface of the plate body 12, which sealingly bear against the inner surface of the container wall facing the interior of the container in order to prevent material from escaping from the container between the container wall and the follower plate 10.During the conveying process, the follower plate 10 is moved toward the bottom of the container, following the decreasing material level in the container, until the container is emptied. The material is conveyed through a material outlet (not shown in detail) in the plate body 12 by means of a container pump 18.

[0010] Arranged in the plate body 12 are a plurality of vent openings 20, which extend between the underside 14 and an upper side 22 of the plate body 12 facing away from the underside 14. At each vent opening 20, the follower plate 10 has a vent valve 24 designed as a needle valve. Each of the vent valves 24 has a plastic valve seat 26 pressed force-fittingly into the plate body 12 and a valve unit 28 detachably connected to the plate body 12 by means of screw connections. Each of the valve units 28 has a valve housing 30 and a valve needle 32 that is linearly displaceable in the valve housing 30, protrudes from the valve housing 30 and, in a closed position, bears sealingly against a conical contact surface 34 of the respective valve seat 26.Furthermore, each valve unit 28 has an actuating device 36 that acts on the valve needle 32 to move it from the closed position to an open position, in which it is lifted from the valve seat 26. A vent channel 38 also extends through the valve housing 30, communicating with the respective vent opening 20 and to which a vacuum pump can be connected.

[0011] When the follower plate 10 is inserted into a container filled with viscous material, the vent valves 24 are opened by moving their valve needles 32 to the open position. Any air contained in the container can then escape from the vent openings 20, or it is actively pumped out using a vacuum pump. When there is no more air in the container between the material surface and the follower plate 10, the vent valves 24 are closed and the material is pumped out of the container by the container pump 18. During venting, the viscous material regularly comes into contact with parts of the vent valves 24. These can therefore become clogged and worn over time due to contamination with the viscous material. During maintenance of the follower plate 10, the valve units 28 are therefore detached from the plate body 12 and removed.The valve needle 32, which protrudes from the valve housing 30 in both the closed and open positions, is then easily accessible and can be cleaned by removing any buildup of viscous material from it. The valve seats 26, which, unlike the valve units 28, cannot be removed from the plate body 12 without causing damage, can also be cleaned. Typically, however, they are removed from the plate body 12, for example, by drilling them out, and replaced with new valve seats 26. In summary, the following can be stated:

[0012] The invention relates to a follower plate 10 for closing an upwardly open container for viscous material, said container having a container bottom and a container wall extending upwardly from the container bottom. The follower plate 10 is movable toward the container bottom, resting against an inner surface of the container wall facing the container interior. The follower plate 10 has a plate body 12 in which a material outlet for conveying the viscous material out of the container and at least one vent opening 20 for discharging air from the container are arranged. According to the invention, a valve seat 26 of a vent valve 24, which is firmly connected to the plate body 12, is arranged in each vent opening 20.

Claims

[1] Follower plate for closing an upwardly open container for viscous material, which container has a container bottom and a container wall extending upwards from the container bottom, which follower plate is movable in the direction of the container bottom while resting against an inner surface of the container wall facing the container interior and which has a plate body (12) in which a material outlet for conveying the viscous material out of the container and at least one vent opening (20) for discharging air from the container are arranged, characterized by that in each vent opening (20) there is arranged a valve seat (26) of a vent valve (24) which is firmly connected to the plate body (12), is an integral part of the plate body (12) and cannot be detached from the plate body (12) without causing damage. [2] Follower plate according to claim 1, characterized by that each of the valve seats (26) is pressed force-fittingly into the plate body (12). [3] Follower plate according to claim 1 or 2, characterized by that each of the valve seats (26) is made of a plastic. [4] Follower plate according to one of the preceding claims, characterized by that each of the valve seats (26) has a conical contact surface (34) for a valve needle (32). [5] Follower plate according to one of the preceding claims, characterized by in that each vent opening (20) is assigned a valve unit (28) which has a valve needle (32) for closing the vent opening (20) at its valve seat (26) and an actuating device (36) for moving the valve needle (32) between a closed position in which it sits sealingly on the valve seat (26) accommodated in the vent opening (20), and an open position in which it is lifted off the valve seat (26). [6] Follower plate according to claim 5, characterized bythat each valve unit (28) has a valve housing (30) through which a venting channel (38) opens into the relevant venting opening (20) extends and from which the valve needle (32) protrudes at least in the closed position. [7] Follower plate according to claim 6, characterized by that the distance by which the valve needle (32) projects from the valve housing (30) in the closed position is at least one third, preferably at least half the thickness of the plate body (12) between its underside (14) and an upper side (22) on which the valve housing (30) sits. [8] Follower plate according to one of claims 5 to 7, characterized by that each valve needle (32) is made of hard metal. [9] Follower plate according to one of claims 5 to 8, characterized by that each valve unit (28) is detachably attached to the plate body (12). [10] Method for maintaining a follower plate according to claim 9, characterized bythat the at least one valve unit (28) is removed from the plate body (12), that the at least one valve seat (26) is removed from the vent opening (20) receiving it and is replaced by a new valve seat (26), and that the at least one valve unit (28) is releasably fastened to the plate body (12) again, wherein the at least one valve seat (26) is destroyed when removed from the vent opening (20) receiving it. [11] Method according to claim 10, characterized by that the at least one valve seat (26) is removed from the vent opening (20) receiving it by means of a machining process.

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