Method for expanding raw material in the form of sand grains

{
  "publication_number": "US9878945B2",
  "country": "US",
  "kind": "B2",
  "title": "Method for expanding raw material in the form of sand grains",
  "abstract": "The invention relates to a method for the expansion of sand grain-shaped raw material (1) in which the raw material drops downwards through a substantially vertical heated shaft (3) provided with means (2) for heating, in which a shaft flow (4) prevails and to a dosing element (6) which can be connected to a substantially vertical shaft (3) and a conveying line (7). In order to prevent the pressure fluctuations coming from the conveying line (7) in the area of the shaft (3), a dosing element (6) is attached between the shaft and the conveying (7) line, in which the quantity of granulate which goes over from the shaft (3) into the conveying line (7) is regulated via means for regulating so that a defined material collection of the granulate is formed as a buffer in the dosing element (6), which decouples the shaft flow (4) from the conveying flow.",
  "claims": [
    "1. Method for the expansion of sand grain-shaped raw material (1) in which the raw material (1) drops downwards through a substantially vertical heated shaft (3) provided with means (2) for heating, in which a shaft flow (4) prevails wherein as a result of the heat transfer in the shaft (3) the raw material (1) expands to expanded granulate (5) and the granulate (5) produced enters into a pneumatic conveying line (7) with a conveying flow (8) for further transport, characterized in that a dosing element (6) is attached between the shaft (3) and the conveying line (7), in which the quantity of granulate (5) which goes over from the shaft (3) into the conveying line (7) is regulated via means (9) for regulating so that a defined material accumulation (10) of the granulate (5) is formed as a buffer in the dosing element (6), which decouples the shaft flow (4) from the conveying flow (8).",
    "2. The method according to claim 1, characterized in that the material accumulation (10) which serves as a buffer is designed in such a manner that at least a first cross-section (11) of the dosing element (6) is filled completely with expanded granulate (5) from the shaft (3) over a defined height.",
    "3. The method according to claim 1, characterized in that the conveying flow (8) is produced by an extraction device (12).",
    "4. The method according to claim 1, characterized in that a separating device, preferably a gas cyclone (13) is provided in the conveying line (7) by means of which the expanded granulate (5) is separated from the conveying flow (8).",
    "5. The method according to claim 3, characterized in that the bulk density of the granulate (5) is determined as a quality feature of the expansion process in order to subsequently regulate the means for heating (2) or reduce the feeding of raw material (1).",
    "6. The method according to any one of claims 1 to 4, characterized in that the means (9) for regulating increases or reduces the conveyed quantity of expanded granulate (5) in the conveying line (7) by means of a local influencing of the conveying flow (8) in the dosing element (6).",
    "7. The method according to claim 1, characterized in that the height of the material accumulation (10) in the dosing element (6) is detected and this information is transmitted to the means (9) for regulating.",
    "8. The method according to claim 1, characterized in that process air (18) is extracted from the head region (16) of the shaft (3) in order to increase and thereby stabilize the part of the shaft flow (4) directed to the head region (16).",
    "9. The method according to claim 1, characterized in that process air (18) is blown in or sucked into the head region (16) of the shaft (3) in order to stabilize the part of the shaft flow (4) directed to the head region (16).",
    "10. System for performing a method according to claim 1 with a dosing element (6) which is connected to a substantially vertical heatable shaft (3) and a pneumatic conveying line (7), characterized in that the dosing element (6) comprises a material container (19) which is connected to the shaft (3) via a shaft connection (20) and has a longitudinal axis (21), a conveying section (22) which is connected to the conveying line (7) via a conveying connection (23) and means (9) for regulating which are configured so that a material accumulation (10) is produced in the area of the material container (19) when granulate (5) enters into the material container (19).",
    "11. The system according to claim 10, characterized in that the conveying section (22) is guided through the material container (19) transversely to the longitudinal axis (21) of the shaft (3).",
    "12. The system according to claim 10, characterized in that the conveying section (22) can be connected to the ambient atmosphere on the side opposite the conveying connection (23).",
    "13. The system according to claim 10, characterized in that on the side opposite the shaft connection (20), the conveying section (22) has at least one opening (24) to ensure transfer of expanded granulate (5) into the conveying section (22).",
    "14. The system according to claim 10, characterized in that a measuring device (15) is attached in the area of the material container (19) by means of which the height of the material accumulation (10) can be detected and which is coupled to the means (9) for regulating the conveyed quantity.",
    "15. The system according to claim 1, characterized in that the means (9) for regulating the conveyed quantity is designed as an inner tube (25) which is disposed inside the conveying section (22) with a butterfly valve (26) located therein.",
    "16. The system according to claim 15, characterized in that the butterfly valve (26) is configured so that it can be closed on the one hand and thereby reduces the cross-section (27) of the inner tube (25) through which flow takes place when an exceeding of a defined height of the material accumulation (10) is detected by the measuring device (15) in order to increase the conveyed quantity and thus reduce the height of the material accumulation (10) and on the other hand can be opened and thus increases the cross-section (27) of the inner tube (25) through which flow takes place when a falling below a defined height of the material accumulation (10) is detected by the measuring device (15) in order to reduce the conveyed quantity and thus increase the height of the material accumulation (10)."
  ],
  "description_excerpt": "The invention relates to a method for the expansion of sand grain-shaped raw material in which the raw material drops downwards through a substantially vertical heated shaft provided with means for heating, in which a shaft flow prevails and to a dosing element which can be connected to a substantially vertical shaft and a conveying line.\n\nA method for producing an expanded granulate from sand grain-shaped raw material is disclosed in WO 2013/053635 A1, where the object consists in adjusting a closed surface of the expanded granulate in a controllable manner so that the expanded granulate exhibits no hygroscopicity or hardly any hygroscopicity. In addition, the possibility of specifically influencing the surface structure of the expanded granulate and therefore the roughness is to be provided. To this end, this document proposes providing a plurality of independently controllable heating elements arranged along the drop section of the sand grain-shaped raw material and performing a temperature detection along the drop section, wherein the heating elements are controlled depending on the detected temperature below the region in which the expansion process takes place. Removal of the expanded granulate from the lower end of the drop section is ensured by means of a pneumatic conveying line into which the drop section opens.\n\nAs a result of the vertical alignment of the shaft and as a result of the additional introduction or extraction of process gases accompanying the expansion process, flows occur inside the shaft which act on the sand grain-shaped raw material.",
  "cpc": [
    "C04B 20/068",
    "B65G 53/58",
    "C04B 20/066",
    "F27B 1/21"
  ],
  "ipc": [
    "C04B 20/06"
  ],
  "assignees": [
    "Binder and Co AG"
  ],
  "inventors": [
    "Harald Tschernko",
    "Marcus Alfred Pusch",
    "Bernhard Neukam",
    "Ernst Erwin Brunnmair"
  ],
  "filing_date": "2015-06-05",
  "publication_date": "2018-01-30",
  "grant_date": "2018-01-30",
  "priority_date": "2014-06-05",
  "application_number": "US-201515315253-A",
  "family_id": "54398630",
  "cited_by_count": 0,
  "citations": [
    "US2625512A",
    "US4180185A",
    "DE19722906A1",
    "WO2009009817A1",
    "WO2013053635A1",
    "WO2015184481A1",
    "WO2015184482A1",
    "US20170107147A1"
  ]
}