EP4433643A1

EP4433643A1 - Vessel having internal vibrator body

Info

Publication number: EP4433643A1
Application number: EP22803395.7A
Authority: EP
Inventors: Lars ANTONSSON
Original assignee: Valmet Oy; Valmet AB
Current assignee: Valmet Technologies Oy; Valmet AB
Priority date: 2021-11-15
Filing date: 2022-11-03
Publication date: 2024-09-25
Also published as: SE2151392A1; WO2023085993A1; CN118202113A

Abstract

A vessel (10) for holding lignocellulosic material (2) comprises a wall (12) enclosing an interior volume (14) for holding the lignocellulosic material (2),and an outlet (50) arranged in the wall (12), preferably in a bottom wall (20), for discharging the lignocellulosic material (2) from the interior volume (14). A vibrator body (60) is positioned within the vessel (10) in the interior volume (14) and is provided with a vibrator (100), the vibrator body (60) being configured to be movable within the vessel (10) when the vibrator (100) is actuated to cause the vibrator body (60) to vibrate. Actuation of the vibrator (100) prevents or breaks up bridging of the lignocellulosic material (2) and facilitates discharge thereof. A method of discharging lignocellulosic material and a method of modifying a vessel for holding lignocellulosic material are also disclosed.

Description

VESSEL HAVING INTERNAL VIBRATOR BODY

TECHNICAL FIELD

The present invention relates to a vessel having an internal vibrator body.

BACKGROUND

Vessels are commonly used for holding lignocellulosic material within the field of producing pulp from the lignocellulosic material. Such vessels may in particular hold lignocellulosic material such as wood chips prior to the treatment of the lignocellulosic material in a treatment vessel such as an impregnation vessel, a digester, and a prehydrolysis vessel.

Vessels for holding lignocellulosic material typically comprise an inlet for entry of lignocellulosic material into the vessel and an outlet for discharging lignocellulosic material. The inlet and outlet may be combined in a combined inlet and outlet but are typically separate and placed at opposing ends of the vessel. The outlet is typically provided at an outlet end of the treatment vessel which may be dome-shaped or conical.

Discharging the lignocellulosic material may involve challenges in that lignocellulosic material exhibits significant friction between individual pieces (wood chips) of lignocellulosic material, and between the lignocellulosic material and the inner surface of the vessel. Such friction may lead to bridging, i.e. where part of the lignocellulosic material arranges itself similar to an inverted cup, i.e. like a vaulted arch bridge or ceiling. This leads to blockages where the lignocellulosic material above the bridged lignocellulosic material cannot move past the latter. The result is that the lignocellulosic material in the vessel cannot be properly discharged.

The risk and occurrence of bridging can be decreased by increasing the diameter and decreasing the height of the vessel, such that the bridging cannot form effectively. Such re-dimensioning of the vessel may however be problematic due to space restrictions in the plant in which the vessel is used, the increased material usage to construct the vessel, and due to the difficulty of discharging lignocellulosic material positioned a significant distance from the outlet.

Other attempts to decrease the risk and occurrence of bridging include increasing the diameter of the outlet, however such measures are only partially effective.

There is accordingly a need for a vessel for holding lignocellulosic material which provides for an efficient discharge of the lignocellulosic material. There is further a need for method of more efficiently discharging lignocellulosic material from a vessel for holding lignocellulosic material.

SUMMARY

At least one of the abovementioned needs or at least one of the further needs which will become evident from the below description, are according to a first aspect of the present invention obtained by a vessel for holding lignocellulosic material, the vessel comprising: a wall enclosing an interior volume for holding the lignocellulosic material, an outlet arranged in the wall for discharging the lignocellulosic material from the interior volume, and a vibrator body positioned within the vessel in the interior volume and being provided with a vibrator, the vibrator body being configured to be movable within the vessel when the vibrator is actuated to cause the vibrator body to vibrate.

The present invention is accordingly based on the recognition by the present inventors that positioning a vibrator body with a vibrator inside the vessel ensures that the vibrations are efficiently transferred to the lignocellulosic material. This provides a more efficient breakup of blockages and bridging, and also causes the lignocellulosic material to flow faster out through the outlet. The vibrator body thus represents a throughput enhancer as it enhances throughput of lignocellulosic material through the vessel. Due the increased efficiency, the energy requirements for the vibrator decreases compared to if the vibrator had been used to vibrate the wall of the vessel or the whole vessel. This allows the use of a smaller vibrator, and also decreases noise that would otherwise arise. Additionally, it is not necessary to mount or suspend the vessel on springs or other devices to allow the whole vessel to vibrate. Vibrating the wall of the vessel or the vessel itself would further place significant strain and stress on the vessel and the wall.

Preliminary studies performed by the present inventors indicate a significant advantage of the vessel according to the first aspect of the present invention. In particular it was found in an example implementation of the vessel in a plant for treating lignocellulosic material that the previous once-an-hour occurring blockages of the vessels in the plant could be avoided completely by using the vessel according to the first aspect of the present invention.

The vessel may alternatively be referred to as a bin, e.g. as a chip bin. The vessel is preferably constructed for holding lignocellulosic material at or near atmospheric pressure. The vessel may have an interior volume of 30- 200 m³, and/or a diameter of up to 6 m, and/or a height of 3- 15 m. The vessel is generally placed vertically when used such that the vessel comprises a top end or top wall and an opposite bottom end or bottom wall. The top end and the bottom end may be dome shaped, cupola shaped, conical, or frustoconical. The vessel may further comprise an inlet for admitting lignocellulosic material into the treatment vessel. The inlet is preferably arranged in the top end or in a side wall of the vessel. The vessel may be configured with a jacket for holding a heating or cooling medium in order to heat the vessel. The vessel is preferably made of metal such as stainless steel.

The vessel may have a generally cylindrical shape, such as a shape comprising cylindrical sections and conical or frustoconical sections. The vessel may in particular comprise alternating cylindrical and frustoconical sections so as to have a diameter that varies along the length axis of the vessel. The vessel may alternatively be referred to as a holding vessel.

The vessel is suitable for holding lignocellulosic material. The vessel may hold the lignocellulosic material prior to, or following, the lignocellulosic material being treated in a treatment vessel such as an impregnation vessel for impregnating lignocellulosic material, a digester for cooking chip slurry to obtain pulp, and a prehydrolysis vessels for treating agricultural residues at acid conditions. Preferably, however, the vessel holds the lignocellulosic material prior to the lignocellulosic material being treated in a treatment vessel. The vessel is preferably suitable for holding dry lignocellulosic material or washed (steam-treated) lignocellulosic material.

The term lignocellulosic material is used herein to mean materials containing lignin, cellulose, and hemicellulose. One example of such materials is wood, others include other agricultural or forestry wastes such as bagasse and wheat straw. Preferably the lignocellulosic material comprises wood chips, in particular dry wood chips or washed or heated (steam treated) wood chips.

The wall is preferably made of metal, such as steel. The wall separates the interior volume from the exterior of the vessel. The wall is preferably dimensioned to hold the lignocellulosic material at or near atmospheric pressure. The wall may comprise a side wall, a top wall at a top end of the vessel, and a bottom wall at a bottom end of the vessel. The wall may further comprise cylindrical wall sections and/or conical or frustoconical wall sections.

The wall encloses, or expressed differently, defines, the interior volume. The interior volume is the volume in which the lignocellulosic material can be held. Generally, the entire interior volume is suitable for holding the lignocellulosic material, however, alternatively, only a part of the interior volume is suitable for holding the lignocellulosic material.

The outlet is preferably an opening or aperture arranged in the wall. The outlet thus establishes a communication between the interior volume and the exterior of the vessel. The outlet is further preferably arranged in a bottom wall at a bottom end of the vessel. More preferably the outlet is centered in the bottom wall, and further centered with a central longitudinal axis of the vessel. The outlet preferably comprises a circular aperture. A conduit for receiving the discharged lignocellulosic material may be connected to the outlet, or the lignocellulosic material may be allowed to fall from the outlet into a receiving vessel arranged below the outlet opening. The outlet is suitable for discharging lignocellulosic material from the treatment vessel by comprising an opening or aperture having a diameter and/or area suitable for allowing the lignocellulosic material to pass through the outlet. The outlet may be provided with a valve or gate for selectively allowing the lignocellulosic material to be discharged from the vessel.

The vibrator body may have any shape. Preferably, however, the shape of the vibrator body is configured to limit the friction between the lignocellulosic material and the vibrator body and to prevent or at least decrease the risk of lignocellulosic material collecting on the vibrator body. The vibrator body is preferably spherical, conical, or pyramidical. More preferably the vibrator body is configured as two cones or pyramids joined base to base. The vibrator body is preferably made from stainless steel.

The vibrator body is positioned within the vessel in the interior volume. The vibrator body will thus be in contact with lignocellulosic material held in interior volume. The vibrator body is preferably suspended within the vessel in the interior volume. The vibrator body may be positioned, e.g. suspended, using one or more cables, chains, or rods running between the vibrator body and one or more mounting surfaces. The mounting surfaces are preferably provided on an inner surface of the wall of the vessel, such as the inner surface of the side wall or top wall of the vessel. Preferably the vibrator body is positioned, e.g. suspended, within the vessel such that it does not contact the wall of the vessel. More preferably the vibrator body is positioned, e.g. suspended, within the vessel such that a central longitudinal axis of the vessel runs through, preferably through the center of, the vibrator body.

The vibrator body is provided with a vibrator. The vibrator is any device capable of vibrating when actuated. The vibrator preferably comprises an electrically or pneumatically driven motor and an unbalanced wheel driven by the motor to provide vibration. Alternatively, the vibrator may comprise an electromagnet and a spring biased iron element configured to move from a first position to a second position when the electromagnet is energized, and to move back to the first position under the action of the spring when the electromagnet is de-energized. A similar arrangement may be obtained by replacing the electromagnet with a pneumatically driven cylinder. Electromagnets or pneumatic cylinders may further be used to move a weight back and forth so as to cause vibrations.

The vibrator is preferably positioned within the vibrator body to separate it from the lignocellulosic material. The vibrator body may thus be considered to comprise or contain the vibrator. The vibrator body is thus further at least partly hollow to be able to accommodate the vibrator within the vibrator body .Additionally, the vibrator body may consist of the vibrator. The vibrator is attached to the vibrator body in such a way that vibrations from the vibrator are transferred to the vibrator body for causing the vibrator body to vibrate. The vibrator body may be provided with a plurality of vibrators to amplify the force of the vibrations or to provide variations in different dimensions, e.g. up, down, left, right, back, forth.

The vibrator body is configured to be moveable within the vessel. This means that the vibrator body is configured to be movable at least a distance within the vessel corresponding to the amplitude of the vibrations of the vibrator body. The vibrator body is preferably configured to be moveable within the vessel by being suspended and/or supported by one or more cables, chains, or rods running between the vibrator body and one or more mounting surfaces on the interior surface of the vessel. The extent of movement allowed can be for example determined by adjusting the length of the cables, chains, or rods running between the vibrator body and the one or more mounting surfaces, as well as varying the position of the endpoints of the cables, chains, or rods. A cable, chain or rod extending generally vertically within the vessel from a mounting surface to the vibrator body may be used to limit the extent of vertical movement of the vibrator body. The introduction of an elastic element between such a cable chain or rod and the vibrator body, or between such a cable, chain or rod and its mounting surface, may be used to increase the allowed extent of vertical movement. A similar effect is obtained by using an elastic cable, chain or rod.

A cable, chain or rod extending generally horizontally within the vessel from a mounting surface to the vibrator body may be used to limit the extent of horizontal movement of the vibrator body. The extent of horizontal movement of the vibrator body may be configured by adjusting the length of the cable or chain so as to allow slack, by inserting an elastic element between the vibrator body and the cable, chain or rod or between the cable, chain or rod and the mounting surface, or by using an elastic cable, chain or rod. Multiple cables, chains or rods, running from different points of the vibrator body in different directions to different mounting surfaces on the inner surface of the vessel, may be used to define the allowed extent of movement of the vibrator body.

Typically, the vibrator body is configured to be movable a distance corresponding to no more than the largest dimension of the vibrator body, preferably no more than 1 /2 of the largest dimension of the vibrator body. The vibrator body is preferably configured, so as to be moveable in a plane perpendicular the longitudinal axis of the vessel, i.e. in a horizontal plane. The vibrator body may however alternatively or additionally be configured, so as to be moveable along the longitudinal axis of the vessel, i.e. in a vertical direction.

Actuation of the vibrator causes the vibrator to vibrate. As the vibrator is comprised by the vibrator body, these vibrations are transferred to the vibrator body, which then begins to vibrate. The vibrations are transferred from the vibrator body to the lignocellulosic material and thus interferes with the lignocellulosic material's capability to form bridging. This facilitates discharge of the lignocellulosic material from the vessel

Preferably the vessel is a chip bin. A chip bin is used for holding wood chips.

Preferably the vibrator body is configured as two cones or pyramids joined base to base, and preferably the vibrator body is positioned such that the vertex of one of the cones or pyramids points towards the outlet.

This is advantageous because such a vibrator body provides low resistance and friction towards lignocellulosic material passing it in the vessel when the lignocellulosic material is discharged through the outlet or filled into the vessel via the inlet. When the vibrator body is positioned such that the vertex of one of the cones or pyramids points towards the outlet, e.g. downwards towards the bottom end of the vessel, then the vertex of the other of the cones or pyramids points upwards, e.g. towards the inlet or the top end of the vessel.

The two cones or pyramids joined base to base comprise a first cone or pyramid having a first base and a first vertex, and a second cone or pyramid having a second base and a second vertex. The first and second bases are joined. The first and second bases may define a common base, i.e. a base common to both the first and the second cone or pyramid. The two cones or pyramids, i.e. the first cone or pyramid and the second cone or pyramid, preferably have similar dimensions. In other words the two cones or pyramids, i.e. the first cone or pyramid and the second cone or pyramid, preferably have similar base areas, similar base diameters, similar heights, and/or similar volumes.

Similar base areas encompass that the base area of one of the two cones or pyramids, such as the first cone or pyramid, is 75- 125% of the base area of the other one of the two cones or pyramids, such as the second cone or pyramid.

Similar base diameters encompass that the base diameter of one of the two cones or pyramids, such as the first cone or pyramid, is 75- 125% of the base diameter of the other one of the two cones or pyramids, such as the second cone or pyramid. For pyramids, the base diameter is represented by the longest side of the base of the pyramids.

Similar heights encompass that the height of one of the two cones or pyramids, such as the first cone or pyramid, is 75- 125% of the height of the other one of the two cones or pyramids, such as the second cone or pyramid. The height is measured from the vertex or point of the cone or pyramid to the base thereof.

Similar volumes encompass that the volume of one of the two cones or pyramids, such as the first cone or pyramid, is 75- 125% of the volume of the other one of the two cones or pyramids, such as the second cone or pyramid.

More preferably each of the base area, base diameter, height, and volume of one of the two cones or pyramids, such as the first cone or pyramid, is 90- 110%, preferably 95- 105%, more preferably 98- 102%, of each of the base area, base diameter, height, and volume of the other one of the two cones or pyramids, such as the second cone or pyramid. Most preferably the base area, base diameter, height, and volume of the two cones or pyramids, i.e. of the first and second cones or pyramids, are the same.

For cones, it is preferred that the base is circular. Similarly, it is preferred that the base of pyramids comprise a like-sided polygon, such as a like-side triangle, square, pentagon, or hexagon.

For cones, it is preferred that the cones are right circular, i.e. where the axis of the cone (which extends from the vertex of the cone to the center of its base) falls perpendicular on the plane of the base. Correspondingly it is preferred for pyramids that the axis of the pyramid (which extends from the vertex of the pyramid to the central point of the base), falls perpendicular on the plane of the base.

Preferably the vibrator body has a maximum diameter which is 50% or less, such as 25-50%, of the diameter of the vessel. This is advantageous in that it provides a good balance between size of the vibrator body, and thus its ability to transfer vibrations into the lignocellulosic material, and the volume taken up by the vibrator body, which volume cannot be used for holding the lignocellulosic material in the vessel. The vibrator body may for example have a maximum diameter which is 30-40 %, such as 34 %, of the maximum diameter of the vessel.

The maximum diameter is measured in the direction perpendicular to the longitudinal axis of the vessel, i.e. horizontally. When the vibrator body is configured as two cones or pyramids joined base to base, then the maximum diameter of the vibrator body is the diameter of the largest base.

The diameter of the vessel is preferably the diameter of the vessel at the position where the center of the vibrator body is positioned. The vibrator body may alternatively have a maximum diameter which is 5-50 %, such as 10-50 %, for example 15-50 % or 10-45%, or 15-40 % such as 20-40 or 20- 30 %, such as in particular 10-35 % or 15-30 %, such a preferably 25 % of the diameter of the vessel. Preferably, the vibrator body is positioned along, preferably centered with, a central longitudinal axis of the vessel. This is advantageous in that it ensures a uniform dispersal of vibrations into the lignocellulosic material. The position along, preferably centered with, the central longitudinal axis of the vessel refers to the position of the vibrator body when the vibrator is not actuated. When the vibrator is actuated the vibrator body will vibrate and thus move, e.g. oscillate, turn and/or wiggle, from this position. Preferably the vibrator body and its positioning are configured such that the vibrator body oscillates, turns, and/or wiggles back and forth around the position it has when the vibrator is not actuated. The central longitudinal axis may also be considered to correspond to a central vertical axis.

Preferably the maximum diameter of the vibrator body is 50- 175 %, such as 75- 160 %, such as 100- 155 %, such as 125- 152 %, of the diameter of the outlet.

Preferably the vibrator body is configured to be movable within the vessel, in a horizontal plane perpendicular to a central longitudinal axis of the vessel, a distance from the central longitudinal axis that is at the most y₂, more preferably at the most i, of the diameter of the vibrator body. This is advantageous in that it ensures that the vibrator body, while being moveable within the vessel as it vibrates, does not move so far from an initial position at the central longitudinal axis that it provides an uneven application of vibrations to the lignocellulosic material, or so that it is pushed aside, and thus forced to provide an uneven application of vibrations to the lignocellulosic material, by the lignocellulosic material as the lignocellulosic material in filled into the vessel through an inlet or discharged from the vessel through the outlet.

This configuration of the vibrator body can preferably be obtained by configuring the vibrator body with cables, chains, or rods running between the vibrator body and one or more mounting surfaces, as described above. Preferably, the vibrator comprises an electrically or pneumatically drivable engine.

The electrically or pneumatically drivable, e.g. energizable, engine may be an electric motor or a pneumatic motor. The electrically or pneumatically drivable, e.g. energizable, engine is preferably configured and provided with an unbalanced wheel, whereby rotation of the unbalanced wheel gives rise to vibrations. Alternatively, the electrically or pneumatically drivable, e.g. energizable, engine may be configured and provided with a linkage for moving a weight back and forth in order to provide vibrations. Electric energy and compressed air, respectively, may be transferred to the vibrator via an electrical lead or a hose for compressed air extending from the vibrator to a valve or aperture arranged in the wall of the vessel. Used air, i.e. air that has been used to drive the pneumatically drivable engine, may be expelled through a one-way valve into the interior volume of the vessel, but may alternatively be evacuated from the vessel using a second hose extending from the vibrator to a second valve or aperture arranged in the wall of the vessel.

Preferably the vibrator (100) is configured to vibrate at a frequency of 5-200 Hz, preferably 10- 100 Hz, more preferably 15-60 Hz. These frequencies provide efficient prevention and / or removal of blockages and bridging.

Preferably the vibrator body is positioned at the outlet. This is advantageous in that bridging usually forms at or above the outlet. Preferably the vibrator body is positioned adjacent the outlet. The vibrator body may for example be provided from a position one diameter of the vibrator body above the opening or aperture of the outlet, to a position in which the lower end of the vibrator body extends reaches the plane defined by the opening or aperture of the outlet. Preferably, the vessel comprises a conical or frustoconical section wherein the vibrator body is positioned at the conical or frustoconical section. This is advantageous in that positions of changes in diameter of the vessel, such as at a conical or frustoconical section of the vessel, are positions at which bridging is liable to occur.

At the conical or frustoconical section encompasses a position directly above, a position within, and a position directly below, the conical or frustoconical section.

Preferably the vibrator body is positioned within the conical or frustoconical section, i.e. within the part of the interior volume defined by the conical or frustoconical section. The conical or frustoconical section preferably has an upper end having a first diameter, and a lower end having a second diameter which is smaller than the first diameter.

Preferably the outlet is arranged in the conical or frustoconical section. This is advantageous in that the conical or frustoconical section may provide a diameter decrease of the vessel at the outlet to simplify access to the outlet. The outlet is preferably arranged in a bottom end or bottom wall of the conical or frustoconical section.

The vessel preferably comprises a plurality of vibrator bodies positioned spaced apart along a central longitudinal axis of the vessel. This is advantageous because there may be multiple positions along the central longitudinal axis where bridging may occur, such an in particular at one or more conical or frustoconical sections and at one or more outlets. The vibrator bodies may have different dimensions, preferably depending on the diameter of the vessel at the position of the respective vibrator body.

When the vessel comprises one or more conical or frustoconical sections as described above, and when the vibrator body is configured as two cones or pyramids joined base to base, then the half angle of the vertex of the one of the cones or pyramids that points towards the outlet may be larger, equal, or smaller than the half angle of the conical or frustoconical section in which the vibrator body is positioned.

When the outlet is arranged in a conical or frustoconical section, and when the vibrator body is configured as two cones or pyramids joined base to base, then the half angle of the vertex of the one of the cones or pyramids that points towards the outlet is preferably smaller, such as 0.5-20° less or preferably 5- 15° less, such as 10° less, than the half angle of that conical or frustoconical section. This configuration allows for positioning the vibrator body closer to the outlet.

Preferably the vessel comprises a plurality of conical or frustoconical sections, and one of the plurality of vibrator bodies is positioned at each conical or frustoconical section. Preferably one of the plurality of vibrator bodies is positioned in the part of the interior volume defined by each conical or frustoconical section. This is advantageous in that it ensures that bridging can be prevented or decreased at each conical or frustoconical section.

One possible configuration of the vessel may thus comprise first and second cylindrical sections, having first and second diameters, spaced apart by a first frustoconical section providing a diameter reduction from the first diameter to the second, followed by a final second conical or frustoconical section in which the outlet is arranged. The diameter of the vessel thus generally decreases from the top end or top wall to the bottom end or bottom wall.

A further possible configuration of the vessel comprises first and second cylindrical sections, having first and second diameters, spaced apart by a first frustoconical section providing a diameter reduction from the first diameter to the second, followed by a final second conical or frustoconical section in which the outlet is arranged. In this configuration a vibrator body configured as two cones or pyramids joined base to base, is positioned in the first frustoconical section. The half angle of the vertex of the one of the cones or pyramids that points towards the outlet is in this configuration larger than the half angle of the first frustoconical section and smaller than the half angle of the second frustoconical section.

Preferably the vibrator body has an upper end, and the vessel further comprises a first cable, chain or rod extending from a side wall or top wall of the vessel to the vibrator body, preferably the upper end thereof, for suspending the vibrator body within the vessel in the interior volume, and preferably an elastic element is provided between the vibrator body, or the upper end thereof, and the cable, chain or rod. This is advantageous in that it provides a simple way of positioning the vibrator body within the vessel so that it is allowed to move when it vibrates.

More than one first cable, chain or rod may be used in combination to limit the horizontal movement of the vibrator body. In particular, three or more first cables, chains or rods, may extend from positions uniformly spaced apart on the inner surface of the side wall or on the inner surface of the top wall of the vessel to intersect at the central longitudinal axis of the vessel so as to limit the horizontal movement of the vibrator body. Alternatively, a single first cable, chain or rod, may extend from the inner surface of the top wall.

It is preferred to position an elastic element, such as a spring or elastic material, between the vibrator body and the first cable, chain or rod to limit the amount of vibrations, and hence noise, that is transferred to the vessel as well as to assist in providing the vibrator body with the freedom of movement required for it to vibrate. As an alternative to the elastic element, the whole or part of the first cable, chain or rod may be configured to be elastic. An elastic element may also be provided between the first cable, chain or rod and the side wall or top wall of the vessel. Preferably the vibrator body has a lower end and the vessel further comprises a second cable, chain or rod extending from a side wall or bottom wall of the vessel to the vibrator body, preferably the lower end thereof, for limiting the horizontal movement of the vibrator body, and preferably an elastic element is provided between the vibrator body, or the lower end thereof, and the cable, chain or rod.

The second cable, chain or rod may be configured as the first cable, chain or rod. In a particular embodiment the vibrator body is positioned using a single first cable, chain or rod extending from the center of the top wall of the vessel to the vibrator body, preferably the upper end thereof, in combination with either:

- a single second cable, chain or rod extending from the center of the bottom wall of the vessel to the vibrator body, preferably the lower end thereof, or

- three or more second cables, chains or rods, extending from positions uniformly spaced apart on the inner surface of the side wall or on the inner surface of the bottom wall to the vibrator body, preferably the lower end thereof.

In a further embodiment the vibrator body is positioned using one or more rods extending from a side wall or bottom wall of the vessel to the vibrator body, preferably the lower end thereof.

At least one of the abovementioned needs or at least one of the further needs which will become evident from the below description, are according to a second aspect of the present invention obtained by a system for holding lignocellulosic material, the system comprising one or more vessels according the first aspect of the present invention. Such a system is advantageous in that provides vessels that are easy to discharge with no or minimized risk of bridging or blockage, while limiting build height and maintaining efficient flow of lignocellulosic material. At least one of the abovementioned needs or at least one of the further needs which will become evident from the below description, are according to a third aspect of the present invention obtained by a method of discharging lignocellulosic material held in a vessel according to the first aspect of the present invention, the method comprising the step of:

- actuating the vibrator prior to or during discharge of the lignocellulosic material through the outlet.

Preferably the vibrator is actuated at a frequency of 5-200 Hz, preferably 10- 100 Hz, more preferably 15-60 Hz.

Whereas the vessel may be manufactured and installed in new plants for treating lignocellulosic material, it is further contemplated that also existing vessels may be retrofitted so as to obtain the benefits of the present invention also for such existing vessels. Accordingly, a fourth aspect of the present invention concerns a method of modifying a vessel for holding lignocellulosic material, the vessel comprising a wall enclosing an interior volume for holding the lignocellulosic material, and an outlet arranged in the wall, preferably in a bottom wall, for discharging the lignocellulosic material from the interior volume, the method comprising the step of:

- positioning a vibrator body according to the first aspect of the present invention within the vessel in the interior volume.

A vibrator body according to the first aspect of the present invention is to be understood as referring to a vibrator body as described above in relation to the vessel according to the first aspect of the present invention. The method may comprise further modifications in order to modify the vessel such that it corresponds to any vessel encompassed by the first aspect of the present invention.

A fifth aspect of the present invention relates to a vibrator body as described above, wherein preferably the vibrator body is configured as two cones or pyramids joined base to base. A sixth aspect of the present invention relates to the use of a vibrator body as described above in a vessel as described above for facilitating discharge and/or resolving and/or preventing bridging and blockages of lignocellulosic material held in the vessel.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the abovementioned and other features and advantages of the present invention will be apparent from the following detailed description of preferred embodiments in conjunction with the appended drawings, wherein:

Fig. 1 shows an embodiment of a vessel according to the first and aspect of the present invention, and

Fig. 2 show another embodiment of the vibrator body.

All the figures are schematic, not necessarily to scale, and generally only show parts which are necessary in order to elucidate the respective embodiments, whereas other parts may be omitted or merely suggested. Any reference number appearing in multiple drawings refers to the same object or feature throughout the drawings, unless otherwise indicated. One or more superscript appended to a reference number indicates that the feature so reference is a variant of the feature assigned that reference number.

DETAILED DESCRIPTION

Fig. 1 shows an embodiment of a vessel 10 according to the first aspect of the present invention. Vessel 10 comprises a wall 12 defining an interior volume 14 for holding lignocellulosic material 2. The vessel 10 further comprises a side wall 16, a top wall 18 (also referred to as a top end) and a bottom wall 20 (also referred to as a bottom end). The vessel 10 shown in Fig. 1 is further made up of cylindrical sections 22 and 24 positioned between frustoconical sections 26, 28 and 30. An inlet 40 is arranged in the top wall 18 for admitting lignocellulosic material 2 into the vessel 10. At the other end of the vessel 10, i.e. at the lower end, an outlet 50 is provided for allowing lignocellulosic material 2 to be discharged from the vessel 10.

Within the vessel 10, in the interior volume 14, a vibrator body 60 is provided. Vibrator body 60 is in Fig. 1 configured as two cones 62 and 64 joined base to base, defining an upper end 66 of the vibrator body 60 corresponding to the vertex of the upper cone 62, and a lower end 68 of the vibrator body 60 corresponding to the vertex of the lower cone. Vibrator body 60 is suspended from a first chain 80 having a first end 82 attached to a mounting surface 84 on the inner surface of the top wall 18. The second end 86 of the chain 80 is attached to the upper end 66 of the vibrator body 60 via an elastic element, in this case a spring 88. Three second chains, two of which are shown in Fig. 1 and designated the reference numerals 90a and 90b, have first ends 92a and 92b attached to corresponding three mounting surfaces, two of which are shown in Fig. 1 and designated 94a and 94b, spaced apart on the inner surface of the side wall 16 of the lower cylindrical section 24, the other ends 96a and 96b being attached to the lower end 68 of the vibrator body 60 via an elastic element in the form of a spring 98.

The first chain 80 suspends and positions the vibrator body 60 within the vessel 10, whereas the three second chains 90a, 90b, anchor the lower end 68 of the vibrator body 60 and together with the springs 88 and 98 limit the horizontal movement of the vibrator body 60 to preferably at the most % of the maximum diameter of the vibrator body 60, more preferably i or less of the maximum diameter.

The maximum diameter of the vibrator body 60, i.e. the diameter of the joined bases of the first and second cones 62, 64, is preferably, as shown here, 25-50 % of the diameter B of the vessel 10 at the point where the vibrator body is positioned. As also shown in Fig. 1, the vibrator body 60 is preferably positioned in a frustoconical section, such as frustoconical sections 28 and 30, and or at the outlet 50. An additional vibrator body, not shown, may for example be placed at the lowermost frustoconical section 30, i.e. at the outlet 50.

As also shown in Fig. 1, the two cones 62 and 64 have circular bases with the same base diameter, and hence the same base areas. The two cones 62 and 64 further have the same heights. Accordingly, the two cones 62 and 64 are identical.

The vibrator body 60 further comprises a vibrator 100 comprising an electric motor 102 configured to rotate an unbalanced wheel 104. Electrical power for powering the electric motor 102 is delivered from outside the vessel 10 via electrical cable 106. Electric motor 102 is further attached to the vibrator body 60 via supports, one of which is designated the reference numeral 108, such that vibrations of the electric motor 102, when rotating the unbalanced wheel 104, are transferred to the vibrator body 60, and from the vibrator body 60 into the lignocellulosic material 2 to break up and / or prevent the formation of bridging.

Although Fig. 1 shows the vibrator body being suspended using chains, other elongated elements such as cables and rods may be used to position the vibrator body 60 within the vessel. Further, whereas Fig. 1 shows the use of a single central first chain 80 and three second chains 90a, 90b, other configurations which position the vibrator body 60 in the vessel 10 are also possible. Such configurations inter alia include three or more first chains in combination with three or more second chains.

Fig. 2 shows, in perspective view, an alternative embodiment of a vibrator body 60’ configured as two pyramids 62’ and 64’ joined base to base.

The two pyramids 62’ and 64’ have square bases with the same base diameter (length of side), and have the same heights.

FEASABLE MODIFICATIONS The invention is not limited only to the embodiments described above and shown in the drawings, which primarily have an illustrative and exemplifying purpose. This patent application is intended to cover all adjustments and variants of the preferred embodiments described herein, thus the present invention is defined by the wording of the appended claims. Thus, the equipment may be modified in all kinds of ways within the scope of the appended claims.

It shall also be pointed out that all information about/ concerning terms such as above, under, upper, lower, etc., shall be interpreted/ read having the equipment oriented according to the figures, having the drawings oriented such that the references can be properly read. Thus, such terms only indicate mutual relations in the shown embodiments, which relations may be changed if the inventive equipment is provided with another structure / design.

It shall also be pointed out that even thus it is not explicitly stated that features from a specific embodiment may be combined with features from another embodiment, the combination shall be considered obvious, if the combination is possible.

Throughout this specification and the claims which follows, unless the context requires otherwise, the word “comprise”, and variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated integer or steps or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

Claims

1. A vessel (10) for holding lignocellulosic material (2), the vessel comprising: a wall (12) enclosing an interior volume (14) for holding the lignocellulosic material (2), an outlet (50) arranged in the wall (12), preferably in a bottom wall (20), for discharging the lignocellulosic material (2) from the interior volume (14), and a vibrator body (60) positioned within the vessel (10) in the interior volume (14) and being provided with a vibrator (100), the vibrator body (60) being configured to be movable within the vessel (10) when the vibrator (100) is actuated to cause the vibrator body (60) to vibrate.

2. The vessel (10) according to claim 1, wherein the vessel is a chip bin.

3. The vessel (10) according to any preceding claim, wherein the vibrator body (60, 60’) is configured as two cones (62, 64) or pyramids (62’, 64’) joined base to base, and wherein preferably the vibrator body (60) is positioned such that the vertex of one of the cones (64) or pyramids (64 j points towards the outlet (50).

4. The vessel (10) according to any preceding claim, wherein the vibrator body (60) has a maximum diameter which is 50 % or less, such as 25-50 %, of the diameter (B) of the vessel (10).

5. The vessel (10 according to any preceding claim, wherein the vibrator body (60) is positioned along, preferably centered with, a central longitudinal axis (A) of the vessel (10).

6. The vessel (10) according to any preceding claim, wherein the vibrator body (60) is configured to be movable within the vessel (10), in a horizontal plane perpendicular to a central longitudinal axis (A) of the vessel (10), a distance from the central longitudinal axis (A) that is at the most , more preferably at the most i, of the diameter of the vibrator body (60) .

7. The vessel (10) according to any preceding claim, wherein the vibrator (100) comprises an electrically or pneumatically drivable engine.

8. The vessel (10) according to any of the preceding claims, wherein the vibrator (100) is configured to vibrate at a frequency of 5-200 Hz, preferably 10- 100, more preferably 15-60 Hz.

9. The vessel (10) according to any preceding claim, wherein the vibrator body (60) is positioned at the outlet (50).

10. The vessel (10) according to any preceding claim, wherein the vessel (10) comprises a conical or frustoconical section (28, 30) wherein the vibrator body (60) is positioned at the conical or frustoconical section (28, 30).

11. The vessel (10) according to claim 10, wherein the outlet (50) is arranged in the conical or frustoconical section (30).

12. The vessel (10) according to any of the preceding claims, comprising a plurality of vibrator bodies (60) positioned spaced apart along a central longitudinal axis (A) of the vessel (10).

13. The vessel (10) according to claim 12, wherein the vessel (10) comprises a plurality of conical or frustoconical sections (28, 30) and one of the plurality of vibrator bodies (60) is positioned at each conical or frustoconical section (28, 30).

14. The vessel (10) according to any preceding claim, wherein the vibrator body (60) has an upper end (66), and wherein the vessel (10) further comprises a first cable, chain or rod (80a) extending from a side wall (16) or top wall (18) of the vessel (10) to the vibrator body (60), preferably the upper end (66) thereof, for suspending the vibrator body (60) within the vessel (10) in the interior volume (14), and wherein preferably an elastic element (88) is provided between the vibrator body (60), or the upper end (66) thereof, and the first cable, chain or rod (80).

15. The vessel (10) according to claim 14, wherein the vibrator body (60) has a lower end (68), and wherein the vessel (10) further comprises a second cable, chain or rod (90a, 90b) extending from a side wall (16) or bottom wall (20) of the vessel (10) to the vibrator body (60), or the lower end (68) thereof, for limiting the horizontal movement of the vibrator body (60), and wherein preferably an elastic element (98) is provided between the vibrator body (60), or the lower end (68) thereof, and the second cable, chain or rod (90a, 90b).

16. A system for holding lignocellulosic material (2), the system comprising one or more vessels (10) according to any of the preceding claims.

17. A method of discharging lignocellulosic material (2) held in a vessel (10) according to any of the claims 1- 13, the method comprising the step of:

- actuating the vibrator (100) prior to or during discharge of the lignocellulosic material (2) through the outlet (50).

18. A method of modifying a vessel ( 10) for holding lignocellulosic material (2), the vessel ( 10) comprising a wall (12) enclosing an interior volume (14) for holding the lignocellulosic material (2), and an outlet (50) arranged in the wall (12), preferably in a bottom wall (20), for discharging the lignocellulosic material (2) from the interior volume (14), the method comprising the step of:

- positioning a vibrator body (60) according to any of the claims 1- 13 within the vessel (10) in the interior volume (14).