An assembly for separating selected defective objects from a group of objects used in tobacco industry, the group comprising regular objects having a form of substantially spherical external surface of a determined diameter and the remaining objects being defective objects, the assembly comprising a sieve element (105) having through channels (106) or holes and a generally flat blocking element (107) located under the sieve element, the blocking element having an upper surface/107B) and through holes (108), the sieve element and the blocking element being displaceable in a direction parallel and/or perpendicular with respect to each other at least between a first configuration and a second configuration. In the first configuration the channels or holes of the sieve element, and the holes of the blocking element enable the regular objects and selected defective objects to enter the upper parts of the channels and they enable the regular objects to fall through the lower parts of the channels and through the holes of the blocking element, while they hold said selected defective objects. In the second configuration the channels or holes of the sieve element and the holes of the blocking element enable said defective objects held in the first configuration to fall through the assembly. A method of separating selected defective objects from a group of objects used in tobacco industry using the assembly according to the invention.

In a sieve apparatus, a housing (1) is provided with an inlet section with a feed inlet for material to be sifted and a discharge section including at least one outlet. Means are provided for vibrating the screen mesh. The housing has two substantially vertical side walls(2), and a screen mesh (5) having at least one side edge (51) is supported by a support structure (6, 7) connected to the respective side wall (2). The support structure includes a support element (7) along each side wall and adapted to support the screen mesh (5). Each support element is provided as a support profile (7) having an inclined support surface (73) for the side edge (51) of the screen mesh and constituting a V-shaped structure protruding into the housing, said support surface (73) meeting a lower surface (74) in an apex (75) located at a distance from the side wall (2) inside the housing (1). Specifically, each V-shaped support profile (7) is formed as an integral part of the respective side wall (2).

In a sieve apparatus, a housing (1) is provided with an inlet section with a feed inlet for material to be sifted and a discharge section including at least one outlet. Means are provided for vibrating the screen mesh. The housing has two substantially vertical side walls(2), and a screen mesh (5) having at least one side edge (51) is supported by a support structure (6, 7) connected to the respective side wall (2). The support structure includes a support element (7) along each side wall and adapted to support the screen mesh (5). Each support element is provided as a support profile (7) having an inclined support surface (73) for the side edge (51) of the screen mesh and constituting a V-shaped structure protruding into the housing, said support surface (73) meeting a lower surface (74) in an apex (75) located at a distance from the side wall (2) inside the housing (1). Specifically, each V-shaped support profile (7) is formed as an integral part of the respective side wall (2).

A method for cleaning of a roller screen transporting and screening particles by means of at least three rotating rollers. The rollers are installed in succession at given clearances and arranged transversally in relation to the transport direction of the particles to screen a desired range of particle sizes. At least one roller changes its circumferential velocity and/or its rotational direction over time at defined time intervals for defined time periods such that for this defined time period for at least one pair of neighbored rollers one roller has a higher circumferential velocity than the other and/or both rollers roll in opposite rotational directions.

A method for cleaning of a roller screen transporting and screening particles by means of at least three rotating rollers. The rollers are installed in succession at given clearances and arranged transversally in relation to the transport direction of the particles to screen a desired range of particle sizes. At least one roller changes its circumferential velocity and/or its rotational direction over time at defined time intervals for defined time periods such that for this defined time period for at least one pair of neighbored rollers one roller has a higher circumferential velocity than the other and/or both rollers roll in opposite rotational directions.

A device for separating the constituents of a fluid medium includes an element for separating the constituents, helping to define, upstream and/or downstream from the separation element, a closed chamber, to which at least one conduit is connected. The conduit includes at least one activatable sealing device, the activation of which is capable of at least partially closing and opening the conduit. The device also includes a controller for the activation of the sealing device, controlling the closing and opening, at least partially, of the conduit cyclically, at a frequency greater than 0.008 Hz.

A device for separating the constituents of a fluid medium includes an element for separating the constituents, helping to define, upstream and/or downstream from the separation element, a closed chamber, to which at least one conduit is connected. The conduit includes at least one activatable sealing device, the activation of which is capable of at least partially closing and opening the conduit. The device also includes a controller for the activation of the sealing device, controlling the closing and opening, at least partially, of the conduit cyclically, at a frequency greater than 0.008 Hz.

Screening media for screening material includes a main body and a plurality of openings extending through the main body between a contact face and back face. The openings are of a shape of a convex and non-regular polygon, and are arranged in an orientation such that a line through the most proximal vertex of the polygon and parallel to a defined material flow direction divides the most proximal interior angle of the polygon. Such a configuration allows the openings to not easily get pegged and to improve screening performance.

Screening media for screening material includes a main body and a plurality of openings extending through the main body between a contact face and back face. The openings are of a shape of a convex and non-regular polygon, and are arranged in an orientation such that a line through the most proximal vertex of the polygon and parallel to a defined material flow direction divides the most proximal interior angle of the polygon. Such a configuration allows the openings to not easily get pegged and to improve screening performance.

Disc screen for separating solid residues, which includes multiple parallel rotation shafts, each of which carries a plurality of discs fixed thereto. In addition, the disc screen includes multiple shaped rings, which are each constituted by multiple sectors removably mounted around the rotation shafts, and they are placed between the discs in order to simply and easily vary the screening section. The external edge of each shaped ring is provided with thrust sections, which are adapted to intercept the material to be screened in order to subject the latter to a greater stress, which facilitates a more efficient separation of the materials, and push upward components of light and filamentous material so as to prevent possible entangling and obstructions of such materials at the rotation shafts.