Follower plate for sealing containers for viscous materials, and method for maintaining said follower plate

Abstract

Follower plate for sealing containers for viscous materials, and method for maintaining said follower plate. A follower plate (10) is used to seal a container for viscous materials, open at the top and having a bottom from which a wall extends upwards. Said follower plate, applied against an inner surface of said wall of the container, is movable towards said bottom of the container and is provided with a body (12) in which are located an outlet, expelling the viscous material, and at least one ventilation orifice (20) for expelling air from said container. A sealing seat (26) for a ventilation valve (24), rigidly connected to the body (12) of the plate, is disposed in each ventilation orifice (20). Figure to be published with the abstract: Fig. 2

Description

Title of the invention: Follower plate for sealing containers for viscous materials, and method for maintaining said follower plate

[0001] The present invention relates to a follower plate for sealing upwardly open containers.

[0002] A follower plate of the aforementioned type is known, for example, from DE 10 2020 127 440 A1. It is an integral part of a device for discharging a viscous material from barrel-type containers, open at the top. To discharge said material, the follower plate is inserted from top to bottom into a container and is moved towards the bottom of said container, pressing in a sealed manner against the inner surface of the wall of said container, resting on the surface of the material located in the latter and following the level of said material which decreases during the emptying of said container, until the latter is emptied. Upon completion of the emptying of said container, the plate is removed from the latter and is introduced into another full container.Said plate is provided with a body, the underside of which rests on the material located in the container, and in which there is a material outlet through which said material is discharged from the drum by means of a discharge pump. At least one ventilation orifice is made in the body of the plate to allow air, trapped between the surface of the material and the underside of said body, to be evacuated before the discharge process begins. When no more air volume is enclosed by the container, said ventilation orifice must be sealed in such a way that no viscous material escapes therefrom, or air does not re-enter said container. For this purpose, each ventilation orifice is provided with a ventilation valve capable of closing and clearing said orifice. Very often, a vacuum pump is also connected to said orifice.

[0003] Since, however, viscous material may enter the ventilation orifice in small quantities during ventilation, it is necessary to regularly clean the ventilation valves to remove fouling caused by said material. This operation is complex and expensive.

[0004] Consequently, the invention aims to improve a follower plate of the type mentioned in the introduction, so as to allow simpler cleaning.

[0005] The characteristics of the invention will emerge more precisely on reading the developments below.

[0006] The invention is based on the idea of ​​integrating a valve seat (or closure seat) into each ventilation orifice, and rigidly connecting it to the body of the plate. In this way, said seat does not constitute a part of a distribution unit removably mounted on said body, but is an integral part of said body. In this case, preferably, each of the shutter seats is force-fitted into the body of the plate, by positive engagement, in such a way that it is retained therein by a frictional connection (press-fit mounting). Each of said shutter seats is conveniently made of a plastic material, so that it is flexible, on the one hand, and can be produced favorably on the other hand. Contaminated seats can then be removed from the body of the plate in a simple manner by a chip removal process, in particular by means of a boring tool. Preferably, moreover, each of the shutter seats is provided with a frustoconical contact surface dedicated to a shutter needle.This allows for a good seal provided, in particular, by a hard metal shutter needle.

[0007] In order to seal, in a sealed manner, the ventilation orifice with minimal or at least present presence, it is provided that a distribution or valve unit, assigned to each ventilation orifice, comprises a shutter needle designed to seal said orifice against the closing seat of the latter, and an actuating device designed to move said shutter needle between a closed position in which it is applied, in a sealed manner, against the closing seat integrated in the ventilation orifice, and an open position in which it is raised away from said closing seat. Each distribution or valve unit is judiciously provided with a casing traversed by a ventilation channel opening into the ventilation orifice concerned, casing beyond which the shutter needle projects, at least in the closed position.Preferably, in particular, the distance by which the shut-off needle protrudes beyond the valve housing, in the closed position, represents at least one third, preferably at least half of the thickness of the body of the plate, between the lower face of the latter and an upper face on which said housing rests, which housing is then located at a distance from the shut-off seat, so that it is less contaminated by the viscous material. Each shut-off needle is suitably manufactured from hard metal which has a high hardness, is chemically resistant and is easy to clean. By the term "hard metal" is meant a metal matrix composite material in which the cohesion of hard substances, present in the form of particles, is ensured by a metal matrix.Metal carbides or metal nitrides, such as, for example, tungsten carbide, titanium carbide, titanium nitride, niobium carbide, tantalum carbide or vanadium carbide, are used as hard substances. Each distribution or valve unit is, in particular, removably attached to the plate body in such a way that it can be removed from said body as a whole without damaging it. Following these . measures, the expensive components of the valve concerned, assembled in the distribution unit, namely the shut-off needle, the valve housing and the actuating device, can be separated without great complexity from the body of the plate, as a unitary assembly, and then cleaned. The shut-off seat, designed as an inexpensive wearing part, on the other hand, remains in said body and is separated from the ventilation orifice in which it is integrated, being then preferably destroyed.When maintaining the follower plate, it is judiciously carried out in such a way that each distribution unit, or even the distribution unit, with minimal or at least present presence, is separated from the body of said plate, and cleaned if necessary; that each of the closure seats, or even the closure seat with minimal or at least present presence is, if necessary, separated from the ventilation orifice in which it is integrated, to then be replaced by a new closure seat; and that, finally, each of the distribution units, or even said distribution unit with minimal or at least present presence is, again, removably fixed to the body of said plate.

[0008] The invention is commented on in more detail below, with the support of an exemplary embodiment illustrated schematically in the attached drawings, in which:

[0009] [Fig-1] is a perspective representation of a follower plate to which a container pump is connected;

[0010] [Fig.2] is a fragmentary section of the follower plate according to [Fig.l];

[0011] [Fig.3] is a perspective illustration of a distribution or valve unit; And

[0012] [Fig.4] is a section of the distribution or valve unit according to [Fig.3].

[0013] A follower plate 10 shown in the drawings is used to discharge a viscous material such as an adhesive, a sealing material, an insulating material or a heat-conducting paste, for example, from a container of the barrel type open at the top, not shown in the drawings. The plate 10 is introduced into said container via the open upper face of the latter. It is provided with a body 12 and exerts, via a lower face 14 of said body 12, pressure on the surface of the material enclosed by said container. Said plate 10 is further provided with two sealing and wiping rings 16 which run along the periphery of a surface of the casing of the body 12 and are applied, in a sealed manner, against the inner surface of the wall of the container facing the internal space thereof in order to prevent material from escaping from said container, between the wall of the latter and the plate 10.During the discharge process, said plate 10 is moved towards the bottom of the container, following the decreasing level of material in the latter, until said container is emptied. The material is discharged by means of a . pump 18 equipping the container, using a material outlet not shown in detail, made in said body 12.

[0014] Several ventilation orifices 20, pierced in the body 12 of the plate, extend between the lower face 14 and an upper face 22 of said body 12 which is turned away from said face 14. At each orifice 20, the plate 10 is provided with a ventilation valve 24 made in the form of a needle valve. Each of the valves 24 comprises a closure seat 26 made of plastic material, force-fitted into the body 12 by positive engagement, as well as a distribution or valve unit 28 removably connected to said body 12 by means of screw connections. Each of the units 28 is provided with a casing 30 and a shutter needle 32 which, capable of sliding linearly in said casing 30, projects beyond said casing 30 and is applied in a sealed manner, in a closed position, against a frustoconical contact surface 34 of the shutter seat 26 concerned.Each unit 28 is furthermore equipped with an actuating device 36 urging the shutter needle 32 in order to move it, from said closed position, to an open position in which it is raised away from the shutter seat 26. The casing 30 is furthermore traversed by a ventilation channel 38 which communicates with the ventilation orifice 20 in question, and to which a vacuum pump can be connected.

[0015] When the follower plate 10 is introduced into a container filled with viscous material, the ventilation valves 24 are opened by moving their shut-off needles 32 to the open position. Air enclosed by the container can then escape through the ventilation orifices 20, or it is actively pumped out by means of a vacuum pump. When no more air volume is trapped between the surface of the material and the plate 10, the valves 24 are closed and said material is forced out of the container by means of the pump 18 fitted thereto. During ventilation, contact of the viscous material with parts of said valves 24 is regularly established. In the long term, therefore, the latter can become clogged by said viscous material following fouling, and undergo wear.Therefore, during maintenance of the follower plate 10, the distribution units 28 are separated from the body 12 of said plate, then removed. The shut-off needle 32, projecting beyond the valve casing 30 both in the closed position and in the open position, is then easily accessible and can be cleaned by removing adhering deposits of viscous material. The shut-off seats 26 which, unlike the units 28, cannot be separated from said body 12 without destruction, or even without damaging them, can also be cleaned. As a general rule, however, they are for example removed from said body 12 by rectification boring, then replaced by new seats 26.

[0016] In summary, the following should be noted: the invention relates to a follower plate 10 for sealing a container open at the top, dedicated to a viscous material and comprising a bottom and a wall extending upwards from said bottom, which plate, applied against an inner surface of the wall of the container facing the internal space thereof, is movable in the direction of said bottom of the container and is provided with a body 12 in which there is a material outlet, assigned to the discharge of said viscous material from the container, and at least one ventilation orifice 20 designed to evacuate air from said container. According to the invention, it is provided that a closure seat 26 of a ventilation valve 24, rigidly connected to said body 12 of the plate, is arranged in each ventilation orifice 20.

[0017] It is understood that numerous modifications may be made to the invention as described and illustrated, without departing from the scope of the content disclosed herein.

[0018] Of course, the invention is not limited to the embodiment described and shown in the attached drawings. Modifications remain possible, in particular from the point of view of the constitution of the various elements or by substitution of technical equivalents, without departing from the scope of protection of the invention.

Claims

Claims

1. Follower plate (10) for closing an upwardly open container, dedicated to a viscous material and comprising a bottom and a wall extending upwards from said bottom, said follower plate, applied against an inner surface of the wall of the container facing the internal space thereof, being movable towards said bottom of the container and being provided with a plate body (12) in which there is a material outlet, assigned to the discharge of said viscous material from the container, and at least one ventilation orifice (20) designed to evacuate air from said container, follower plate characterized in that a valve or closure seat (26) of a ventilation valve (24), rigidly connected to the plate body (12), is arranged in each ventilation orifice (20).

2. Follower plate according to claim 1, characterized in that each of the closure seats (26) is an integral part of the body (12) of said plate.

3. Follower plate according to claim 1 or 2, characterized in that each of the closure seats (26) is force-fitted, by positive engagement, into the body (12) of said plate.

4. Follower plate according to any one of the preceding claims, characterized in that each of the closure seats (26) is made of a plastic material.

5. Follower plate according to any one of the preceding claims, characterized in that each of the closure seats (26) is provided with a frustoconical contact surface (34) dedicated to a closure needle (32).

6. Follower plate according to any one of the preceding claims, characterized in that a distribution or valve unit (28), assigned to each ventilation orifice (20), comprises a shutter needle (32) designed to close said orifice (20) against the closing seat (26) of the latter, and an actuating device (36) designed to move said shutter needle (32) between a closed position in which it is applied, in a sealed manner, against the closing seat (26) integrated in the ventilation orifice (20), and an open position in which it is raised away from said closing seat (26).

7. Follower plate according to claim 6, characterized in that each distribution or valve unit (28) is provided with a casing (30) traversed by a ventilation channel (38) opening into the ventilation orifice (20) concerned, casing beyond which the shutter needle (32) projects, at least in the closed position.

8. Follower plate according to claim 7, characterized in that the distance, by which the shutter needle (32) projects beyond the valve housing (30) in the closed position, represents at least one third, preferably at least half of the thickness of the body (12) of said plate, between the lower face (14) thereof and an upper face (22) on which said housing (30) rests.

9. Follower plate according to any one of claims 6 to 8, characterized in that each shutter needle (32) is made of hard metal.

10. Follower plate according to any one of claims 6 to 9, characterized in that each distribution or valve unit (28) is removably fixed to the body (12) of said plate.

11. Method for maintaining a follower plate (10) according to claim 10, characterized in that the distribution unit (28), at least present, is dissociated from the body (12) of the plate; in that the closure seat (26), at least present, is separated from the ventilation orifice (20) in which it is integrated, to then be replaced by a new closure seat (26); and in that said distribution unit (28) at least present is, again, removably fixed to the body (12) of said plate.

12. Method according to claim 11, characterized in that the minimally present closure seat (26) is destroyed when it is separated from the ventilation orifice (20) in which it is integrated.

13. Method according to claim 12, characterized in that the minimally present closure seat (26) is separated, by a chip removal process, from the ventilation orifice (20) in which it is integrated.

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