SILO

Abstract

A silo for storing bulk material, the silo comprising: a container defining an inner space, at least one supply opening for receiving bulk material, an insert located in said inner space, the insert having the shape of a capped cone, the bottom rim of the insert being mechanically coupled to the inner surface of the container, the insert having one or more openings, along its bottom rim for allowing bulk material to pass from the upper inner space to the lower inner space, a first group of discharge openings near or at the lower side of the container in the surface of the container for discharging bulk material from the lower inner space, the top rim is provided with a second group of discharge openings comprising at least one discharge opening for discharging bulk material from the upper inner space, a recirculation system coupled to the discharge openings of one of the first and second group of discharge openings, for transporting bulk material from said discharge openings to said supply opening, and an extraction system being coupled to the discharge openings of the other of the first and second group of discharge openings for extracting bulk material towards the exterior of the silo.

Claims

1. A silo for storing bulk material comprising: a container defining an inner space; at least one supply opening for receiving bulk material, the at least one supply opening being disposed near or at an upper side of the container; an insert disposed within the inner space, the insert having a shape of a capped cone with a top side having a top rim and a bottom side having a bottom rim, wherein: the top side of the insert is oriented towards the upper side of the container, the bottom rim of the insert is mechanically coupled to an inner surface of the container thereby defining, within the container, an upper inner space above the insert and a lower inner space below the insert, and the insert defines one or more openings, such as one or more slits, along its bottom rim for allowing bulk material to pass from the upper inner space to the lower inner space; a first group of discharge openings comprising at least one discharge opening, the openings of the first group of discharge openings being provided near or at the lower side of the container in the surface of the container for discharging bulk material from the lower inner space below the insert, wherein the top rim is provided with a second group of discharge openings comprising at least one discharge opening for discharging bulk material from the upper inner space above the insert; a recirculation system coupled to the discharge openings of one of the first and second group of discharge openings, for transporting bulk material from said discharge openings to said supply opening; and an extraction system being coupled to the discharge openings of the other of the first and second group of discharge openings for extracting bulk material towards the exterior of the silo.

2. A silo according to claim 1, wherein, the container defines the inner space by having an upper cylindrical portion and a lower conical portion that define the inner space.

3. A silo according to claim 2, wherein the bottom rim is mechanically coupled to the inner surface of the container at the transition between the upper cylindrical portion and the lower conical portion.

4. A silo according to claim 2, wherein the bottom rim is mechanically coupled to the inner surface of the container at a position along the conical portion.

5. A silo according to claim 2, wherein the extraction system comprises an extraction duct coupled to the upper rim.

6. A silo according to claim 2, wherein the upper cylindrical portion has a diameter in the range of 6 feet to 12 feet.

7. A silo according to claim 1, wherein the silo comprises a supply duct for supplying fresh bulk material.

8. A silo according to claim 1, wherein the volume of the upper inner space above the insert is more than 10 times the volume of the lower inner space below the insert.

9. A silo according to claim 1, wherein the openings along the bottom rim of the insert have a total surface area of 4 to 15 feet.sup.2.

10. A silo according to claim 1, wherein the opening defined by the top rim is 5 to 20% of the surface of the cross section of the inner space defined by the plane with which the opening defined by the top rim is coplanar with.

11. A silo according to claim 1, wherein a height of the container above a mechanical coupling of the insert to the inner surface of the container is between 30 and 60 feet.

12. A silo according to claim 1, wherein a height of the container below a mechanical coupling of the insert to the inner surface of the container is between 1 and 5 feet.

13. A silo according to claim 1, wherein the recirculation system is coupled to the discharge openings of the first group of discharge openings, and the extraction system is coupled to the discharge openings of the second group of discharge openings.

14. A silo according to claim 1, wherein the recirculation system coupled to the discharge openings of the second group of discharge openings, the extraction system being coupled to the discharge openings of the first group of discharge openings.

15. A method to extract bulk material from a silo, the method comprising the steps of: providing a silo according to claim 1; feeding fresh bulk material to said silo via a supply opening; simultaneously discharging bulk material via the discharge openings of the first and second group of discharge openings; and recirculating the bulk material discharged via recirculation system to the silo via a supply opening.

16. A method according to claim 15, wherein a volume per hour of bulk material extracted via the extraction system substantially equals the volume per hour of the fresh bulk material fed to the silo via the supply opening.

17. A method according to claim 15, wherein a silo according to claim 13 is provided, and a volume per hour ratio of a volume of bulk material extracted via the extraction system to a volume of bulk material recirculated via the recirculation system is in the range of 1/1 to 1/25.

18. A method according to claim 15, wherein the bulk material are PET flakes.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0103] Having described various embodiments in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:

[0104] FIGS. 1-3 are schematic diagrams of silos according to the first aspect of the invention.

[0105] The same reference signs refer to the same, similar or analogous elements in the different figures.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0106] Various embodiments will now be described in greater detail. It should be noted that the term comprising, used in the claims, should not be interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It is thus to be interpreted as specifying the presence of the stated features, steps or components as referred to, but does not preclude the presence or addition of one or more other features, steps, or components, or groups thereof. Thus, the scope of the expression a device comprising means A and B should not be limited to devices consisting only of components A and B. It means that with respect to the claimed embodiment, the only required components of the device are A and B.

[0107] Throughout this specification, references to one embodiment or an embodiment are made. Such references indicate that a particular feature described in relation to the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases in one embodiment or in an embodiment in various places throughout this specification are not necessarily all referring to the same embodiment, though they could.

[0108] Furthermore, the particular features or characteristics described may be combined in any suitable manner in one or more embodiments, as would be apparent to one of ordinary skill in the art.

[0109] A silo 100 for storing bulk material, in this case PET flakes 900, is shown in FIG. 1. The silo 100 comprises a container 110 defining an inner space. The container 110 is closed at its top side by means of a closing lid 112.

[0110] The container defines the inner space 114 by having an upper cylindrical part 116 and a lower conical part 118. The lower conical part 118 is oriented with its top of the conical shape downwards. The silo 100 has a hopper-like shape. As an example, the cylindrical part has a diameter of 8 feet. In an example, the height of the cylindrical part may be, for example, 56 feet. The height of the conical part may be 7 feet and the inclination angle is 30.

[0111] The container 100 has at least one supply opening 120 for receiving PET flake being provided at the upper side of the container and is centrally positioned. As such the supply opening is coaxial with the axis of the cylindrical and conical part of the container. The silo comprises a supply duct 121 for supplying fresh PET flakes. The supply duct for supplying the fresh and recirculated PET flakes is situated at the top of the silo 100, in this embodiment in the lid 112 of the container.

[0112] A first group of four discharge openings 122 are provided on the lower side of the container 110 in the surface of the container, in this embodiment in the conical part 118 of the container 110. The four openings are equally distributed at the conical part 118 of the container 110. Via a recirculation ducting system 124, the discharge openings 122 are coupled to the supply opening 120. In particular embodiments, this system is provided with means (not shown) to transport the flakes using air current. Each discharge opening 122 is coupled to its own discharge duct 126. In particular embodiments, all discharge openings 122 and the supply duct 121 are coupled to one supply opening 120. The discharge openings 122 may have a circular shape with diameter of, e.g., 12 inches and the ducts 126 coupled to these openings may have the same diameter.

[0113] The silo 100 further comprises an insert 130 located in the inner space 114, which insert 130 has the shape of a capped cone with a top side 132 having a top rim 134 and a bottom side 136 having a bottom rim 138. The top side 132 of the insert 130 is oriented towards the upper side of the container 110. The capped cone has an inclination angle between its surface and its axis of about 55. The top rim circumscribes the one discharge opening 133 of the second group of discharge openings.

[0114] The bottom rim 138 of the insert 130 is mechanically coupled to the inner surface of the container 100 by means of a limited number of studs, e.g. 4 studs. As such an upper inner space 142 above the insert 130 and a lower inner space 144 below the insert 130 is defined. The bottom rim 138 is mechanically coupled to the inner surface of the container 100 at the transition between the upper cylindrical part 116 and the lower conical part 118.

[0115] In particular embodiments, the whole container and the ducting systems are made of steel. The mechanical coupling may be a welding.

[0116] In particular embodiments, the volume of the inner space 142 above the insert 130 is about 14 times of the volume of the inner space 144 below the insert 130.

[0117] The insert 130 has a plurality of openings 150 along its bottom rim 138 for allowing PET flakes to pass from the upper inner space 142 to the lower inner space 144.

[0118] The discharge opening 133 at the top rim 134 is coupled to the duct of an extraction system 160 for extracting PET flakes from the upper inner space 142 towards the exterior of the silo. The extraction system 160 comprises an extraction duct 162 coupled to the upper rim 134 of the insert 130 while the extraction duct 162 intersects with the lower conical part 118 of the container 110 at the top of the conical shape of the conical lower part 118.

[0119] In particular embodiments, the discharge opening 133 defined by the top rim 134 has a diameter of 12 inches and the duct 162 coupled to this opening 133 has the same diameter.

[0120] The capped conical shape of the insert 130, the cylindrical 116 and conical part 118 of the silo, the supply opening 120, and the extraction duct of the extraction ducting system 160 may be coaxially mounted.

[0121] As an alternative, the bottom rim may be mechanically coupled to the inner surface of the container at a position along the upper cylindrical part, such that the distance between the transition between conical and cylindrical part and the mechanical coupling is between 0 and 3 feet.

[0122] In various embodiments, the bottom rim 138 of the insert 130 is coupled to the container with four studs positioned radially equidistant one from the other. The openings 150 along the bottom rim 138 of the insert 130 have a slit shape with width of about 6 inches. The total surface area of these openings is about 12 feet.

[0123] In steady state operation, the container may be filled with PET fakes. Fresh PET flakes, e.g. flakes of PET obtained by recycling PET bottles, are provided to the container 100 via opening 120 and duct 121. At the bottom of the container, PET flakes are extracted via opening 134 and duct 162, in some embodiments at the same volume rate per hour as is applicable for the fresh PET flake feed.

[0124] PET flakes may be recirculated by extraction through the discharge openings 122 and recirculated to the supply opening 120.

[0125] In particular embodiments, the volume per hour ratio of the volume of PET flakes extracted via the top rim opening 133 to the volume of PET flakes extracted via the one or more discharge openings 122 is in the range of between 1/25 and 1/1, in some embodiments in the range of between 1/20 and 1/1.25. For example, the volume per hour ratio of the volume of PET flakes extracted via the top rim opening 133 is about 40000 pound per hour, whereas the volume of PET flakes extracted via the discharge openings 122 is 8000 pounds per hour.

[0126] Another silo 1000 for storing PET flakes 900 is shown in FIG. 2. The silo 1000 comprises a container 1010 defining an inner space 1014. The container 1010 is open at its top side.

[0127] The container defines the inner space 1014 by having an upper cylindrical part 1016 and a lower conical part 1018. The lower conical part 1018 is oriented with its top of the conical shape directed downwards. The silo 1000 has a hopper-like shape. In particular embodiments, the cylindrical part has a diameter of 8 feet. The height of the cylindrical part may, e.g., be 46 feet. The height of the conical part may, e.g., be 4 feet and the inclination angle may, e.g., be 45.

[0128] In various embodiments, the open top of the container 1000 provides one supply opening 1020 for receiving PET flake being provided at the upper side of the container. The silo comprises a supply duct 1021 for supplying fresh PET flakes. The supply duct for supplying the fresh and recirculated PET flakes is situated at the top of the silo 1000.

[0129] One discharge opening 1022 is provided at the lower side of the container 1010, in this embodiment at the top of the conical part 1018 of the container 1010. Via a recirculation system 1024 comprising a bucket conveyor system 1026, the discharge opening 1022 is coupled to the supply opening 1020, being the open top of the cylindrical part 1016. In particular embodiments, the discharge opening has a circular shape with diameter of 12 inches.

[0130] The silo 1000 further comprises an insert 1030 located in the inner space 1014, which insert 1030 has the shape of a capped cone with a top side 1032 having a top rim 1034 and a bottom side 1036 having a bottom rim 1038. The top side 1032 of the insert 1030 is oriented towards the upper side of the container 1010. In particular embodiments, the capped cone has an inclination angle between its surface and its axis of 45.

[0131] In various embodiments, the bottom rim 1038 of the insert 1030 is mechanically coupled to the inner surface of the container 1000 with four studs radially equally distant one from the other. As such, an upper inner space 1042 above the insert 1230 and a lower inner space 1044 below the insert 1030 is defined. The bottom rim 1038 is mechanically coupled to the inner surface of the conical part 1018 of the container 1000 at a height along the axis of the conical part. In particular embodiments, such a height is about 50% of the total height of the conical shape of the conical part 1018.

[0132] In particular embodiments, the whole container and the ducting systems are made of steel. The mechanical coupling may be a welding.

[0133] The insert 1030 has 4 slit-shaped openings 1050 along its bottom rim 1038 for allowing PET flakes to pass from the upper inner space 1042 to the lower inner space 1044.

[0134] The one discharge opening 1033 of the second group of discharge openings is circumscribed by the top rim 1034, which may be coupled (e.g., on its turn) to an extraction duct system 1060 for extracting PET flakes from the upper inner space 1042 towards the exterior of the silo. The extraction duct system 1060 comprises an extraction duct 1062 coupled to the upper rim discharge opening 1033 of the insert 1030, where the extraction duct 1062 intersects with the lower conical part 1018 of the container 1010 along the side of the conical part 1018.

[0135] In particular embodiments, the opening 1033 defined by the top rim 1034 has a diameter of 12 inches and the duct 1062 coupled to this opening 1038 initially has the same diameter, broadening to 24 inches further downstream.

[0136] In particular embodiments, the capped conical shape of the insert 1030, the cylindrical 1016 and conical part 1018 of the silo, the supply opening 1020, the discharge opening 1022 of the recirculation ducting system 1024, and the extraction duct 1062 of the extraction ducting system 1060 are coaxially mounted.

[0137] In particular embodiments, the openings 1050 along the bottom rim 1038 of the insert 1030 have a slit-like shape with width of about 6 inches.

[0138] In steady state operation, the container is filled with PET fakes. Fresh PET flakes, e.g., flakes of PET obtained by recycling PET bottles, may be provided to the container 1000 via the opening 1020 at the top of the container and duct 1021. At the bottom of the container, PET flakes may be extracted via opening 1033 and duct 1062, in some embodiments at the same volume rate per hour as is applicable for the fresh PET flake feed.

[0139] In various embodiments, via discharge openings 1022, PET flakes are recirculated by extraction through these openings and recycled to the supply opening 1020.

[0140] The volume per hour ratio of the volume of PET flakes extracted via the top rim opening 1033 to the volume of PET flakes extracted via the discharge openings 1022 may be in the range of between 1/25 and 1/1, for example, in the range of between 1/20 and 1/1.25. In particular embodiments, the volume per hour ratio of the volume of PET flakes extracted via the top rim opening 1033 is about 40000 pound per hour, whereas the volume of PET flakes extracted via the discharge openings 1022 is 8000 pounds per hour.

[0141] It should be understood that these silos 100 and 1000 may be used for bulk material other than PET flakes.

[0142] A further silo 2000 for storing bulk material 2900, is shown in FIG. 3. The silo 2000 comprises a container 2110 defining an inner space. The container 2110 is closed at its top side by means of a closing lid 2112.

[0143] The container defines the inner space 2114 by having an upper cylindrical part 2116 and a lower conical part 2118. The lower conical part 2118 is oriented with its top of the conical shape downwards. The silo 2000 has a hopper-like shape. In particular embodiments, the cylindrical part has a diameter of 8 feet. The height of the cylindrical part may be, e.g., 56 feet. The height of the conical part may be, e.g., 7 feet and the inclination angle may be, e.g., 30.

[0144] The container 2000 has at least one supply opening 2120 for receiving bulk material being provided at the upper side of the container and is centrally positioned. As such, the supply opening may be coaxial with the axis of the cylindrical and conical part of the container. The silo comprises a supply duct 2121 for supplying fresh bulk material. The supply duct for supplying the fresh and recirculated bulk material may be situated at the top of the silo 2000, in this embodiment in the lid 2112 of the container.

[0145] In various embodiments, a first group of four discharge openings 2122 are provided on the lower side of the container 2110 in the surface of the container, in this embodiment in the conical part 2118 of the container 2110. The four openings are equally distributed at the conical part 2118 of the container 2110.

[0146] The discharge opening 2122 are coupled to the duct of an extraction system 2160 for extracting bulk material from the lower inner space 2144 towards the exterior of the silo. The extraction system 2160 comprises extraction ducts 2162 coupled to the discharge openings 2122.

[0147] The silo 2000 further comprises an insert 2130 located in the inner space 2114, which insert 2130 has the shape of a capped cone with a top side 2132 having a top rim 2134 and a bottom side 2136 having a bottom rim 2138. The top side 2132 of the insert 2130 is oriented towards the upper side of the container 2110. The capped cone has an inclination angle between its surface and its axis of about 55. The top rim circumscribes one or more discharge openings 2133 of the second group of discharge openings.

[0148] Via a recirculation ducting system 2124, the discharge opening 2133 is coupled to the supply opening 2120. This system is provided with means (not shown) to transport the flakes using air current. The discharge opening 2133 is coupled to a discharge duct 2126. In particular embodiments, the discharge openings 2133 have a circular shape with diameter of 12 inches and the ducts 2126 coupled to these openings having the same diameter.

[0149] In various embodiments, the bottom rim 2138 of the insert 2130 is mechanically coupled to the inner surface of the container 2000 by means of one or more studs, e.g., 4 studs. In this way, an upper inner space 2142 above the insert 2130 and a lower inner space 2144 below the insert 2130 may be defined. The bottom rim 2138 may be mechanically coupled to the inner surface of the container 2000 at the transition between the upper cylindrical part 2116 and the lower conical part 2118.

[0150] In particular embodiments, the whole container and the ducting systems are made of steel. The mechanical coupling may be a welding.

[0151] In particular embodiments, the volume of the inner space 2142 above the insert 2130 is about 14 times of the volume of the inner space 2144 below the insert 2130.

[0152] The insert 2130 may have a plurality of openings 2150 along its bottom rim 2138 for allowing bulk material to pass from the upper inner space 2142 to the lower inner space 2144.

[0153] In particular embodiments, the discharge opening 2133 defined by the top rim 2134 has a diameter of 12 inches and the duct 2126 coupled to this opening 2133 has the same diameter.

[0154] In particular embodiments, the capped conical shape of the insert 2130, the cylindrical 2116 and conical part 2118 of the silo, the supply opening 2120, and the part of the duct 2014 where it is coupled to the opening 2133 are coaxially mounted.

[0155] In various embodiments, the bottom rim may be mechanically coupled to the inner surface of the container at a position along the upper cylindrical part, such that the distance between the transition between conical and cylindrical part and the mechanical coupling is, for example, between 0 and 3 feet.

[0156] In particular embodiments, the bottom rim 2138 of the insert 2130 is coupled to the container with four studs positioned radially equidistant one from the other. The openings 2150 along the bottom rim 2138 of the insert 2130 have a slit shape with width of about 6 inches. The total surface area of these openings is about 12 feet.

[0157] In steady state operation, the container may be filled with bulk material. Fresh bulk material is provided to the container 2000 via opening 2120 and duct 2121. At the bottom of the container, bulk material is extracted via openings 2122 and duct 2160, in some embodiments at the same volume rate per hour as is applicable for the fresh PET flake feed.

[0158] In various embodiments, bulk material is recirculated by extraction through discharge openings 2133 and recirculated to the supply opening 2120.

[0159] It is to be understood that although specific embodiments and/or materials have been described herein, various modifications or changes may be made without departing from the scope and spirit of this invention.