Apparatus and method for feeding and preheating a metal charge in a melting furnace

Patent metadata

Field	Value
Publication number	US-2022099373-A1
Application number	US-202117487030-A
Country	US
Kind code	A1
Filing date	Sep 28, 2021
Priority date	Sep 29, 2020
Publication date	Mar 31, 2022
Grant date	—

Abstract

An apparatus for feeding and preheating a metal charge toward a melting furnace of a melting plant, comprising at least one conveyor channel for said metal charge, at least one hood disposed above said conveyor channel and scrap detection means able to identify the profile of the metal charge entering said conveyor channel. The present invention also concerns a plant for melting metal comprising said apparatus, and a method to feed and preheat a metal charge.

First claim

1 . An apparatus for feeding and preheating a metal charge toward a melting furnace of a melting plant, comprising:
at least one conveyor channel for said metal charge defining at least one support and advance surface, at least one hood disposed above said conveyor channel at a hood height, defining with it a tunnel along which a flow of fumes is able to pass in order to heat said metal charge, scrap detection means able to identify the profile of the metal charge entering said conveyor channel,
wherein it also comprises adjustment means associated with said at least one hood in order to move it vertically away from/toward said support and advance surface of the conveyor channel in order to vary said hood height as a function at least of the detected profile of said metal charge.

2 . The apparatus as in claim 1 , wherein at least one hood is mobile at least between a lowered position, in which the hood height is equal to a minimum hood height value, an intermediate position, in which the hood height is equal to an intermediate hood height value, and a raised position, in which the hood height is equal to a maximum hood height value.

3 . The apparatus as in claim 1 , wherein it comprises a plurality of hoods disposed and attached in succession by respective rigid mechanical joints and vertically movable in a coordinated manner.

4 . The apparatus as in claim 1 , wherein it comprises a plurality of hoods disposed and attached in succession by means of respective flexible mechanical joints, with each of said hoods there being associated a respective plurality of adjustment means configured to move the respective hood independently from the others.

5 . The apparatus as in claim 1 , also comprising a sealing unit associated with said at least one hood, on the opposite side with respect to the furnace entrance side, cooperating with said conveyor channel in order to define an initial segment of said tunnel, said sealing unit being provided with:
a frame having an upper wall and two opposite lateral flanks, and a plurality of bands, for example vertical ones, associated in a suspended manner with said upper wall and adjacent in order to form one or more rows disposed at a certain distance from each other in the direction of advance of the metal charge inside said tunnel,
wherein it also comprises movement means associated with said frame in order to move it vertically away from/toward said support and advance surface of said conveyor channel, varying its vertical distance so that said vertical bands are able to seal the metal charge in transit in a desired manner.

6 . The apparatus as in claim 5 , wherein said bands can be moved independently with respect to said frame.

7 . The apparatus as in claim 1 , wherein said conveyor channel comprises a bottom wall and two lateral channel walls, and said at least one hood comprises respective lateral hood walls opposite each other, and a covering wall located at the top, said lateral hood walls being associated with said lateral channel walls by means of adaptable sealing means.

8 . The apparatus as in claim 1 , wherein said adjustment means comprise a plurality of lifting devices selected from a group comprising at least one of either a jack, a linear actuator, sliding guides, chain mechanisms, rack or worm screw mechanisms.

9 . The apparatus as in claim 1 , wherein at least one hood, or the last hood, is terminally provided with a panel which projects vertically from the covering wall and is provided internally with a liquid cooling circuit.

10 . The apparatus as in claim 1 , wherein it comprises a processing and control unit configured at least to receive a first operating signal from the scrap detection means containing at least information relating to the profile of the metal charge, and to process and send respective control operating signals at least to said adjustment means.

11 . A plant for melting metal, comprising a melting furnace, continuously fed with a metal charge, a charging module, in which said metal charge is able to be deposited before being introduced into the melting furnace, and an apparatus for feeding and preheating said metal charge as in any claim 1 .

12 . A method to feed and preheat a metal charge to a melting furnace of a melting plant, wherein said method provides to:
detect continuously, or at pre-established intervals, the profile of the metal charge as it is gradually supplied, make said metal charge available on a conveyor channel which moves it toward the furnace, there being present, in cooperation with said conveyor channel, at least one hood at a hood height with respect to a support and advance surface of said conveyor channel,
wherein it also provides to vertically move, by means of adjustment means, said at least one hood away from/toward said support and advance surface in order to vary said hood height at least as a function of the detected profile of said metal charge.

13 . The method as in claim 12 , wherein it also provides to:
calculate the area of the section of the tunnel defined by said conveyor channel and by said at least one hood disposed above, based on knowledge of the current hood height, calculate the area of the metal charge corresponding to the area of the section occupied by the metal charge in transit on the basis of the profile detected, calculate the fumes passage area as the difference between said area of the section of the tunnel and said area of the metal charge, calculate the average passage speed of the fumes as the ratio between a current flow rate of fumes movement means and said difference between said area of the section of the tunnel and said area of the metal charge, compare the average fumes passage speed with a desired fumes passage speed value, dynamically modify said height of said at least one hood in order to obtain said desired fumes passage speed value.

14 . The method as in claim 13 , wherein it provides to vary said hood height at least as a function of an average scrap height of the metal charge in transit.

Assignees

• Danieli Off Mecc

Inventors

• Scubla Stefano
• Rondini Nicola
• Burin Paolo

Classifications

• F27D17/10

  Arrangements for using waste heat · CPC title

• Y02P10/20

  Recycling · CPC title

• C21C2005/5288

  Measuring or sampling devices · CPC title

• F27D13/002 Primary

  Preheating scrap · CPC title

• F27D2019/0059

  Regulation involving the control of the conveyor movement, e.g. speed or sequences · CPC title