Device to inject solid material into a bath of liquid metal, and corresponding method

Abstract

Device and method for injecting solid material in particles, powder or granulated form, of varying grain size. The device comprises a tubular pipe which can be applied on a lateral wall of a melting furnace so as to dispose its exit end inside the volume of the melting furnace and above the meniscus of the liquid metal. The device also comprises a chamber or tank to contain the solid material and emitter means comprising valve means which can be selectively opened for an opening time in the range of tenths of a second, to introduce an impulsive jet of pre-compressed gas or air which, in coordination with the opening of an exit valve which can be selectively opened, disposed at one end of said pipe, determines the emission of an impulsive flow of the solid material contained in said chamber or tank, with high kinetic energy and quantity of motion.

1 .- 13 . (canceled) 
     
     
         14 . An injection device for injecting a discrete amount of solid material in particle, powder or granulated form, comprising:
 a melting furnace having walls defining a liquid metal retaining area,   a first pipe having a lower end, an upper end and mounted through a lateral wall of the melting furnace wherein the lower end of the first pipe is disposed inside the furnace and configured to be above a meniscus of liquid metal contained within the liquid metal retaining area,   a chamber configured to store the solid material and having an upper part and a lower end,   an exit valve connecting the upper end of the first pipe to a lower end of the chamber wherein the exit valve is configured to be selectively opened for a period between about 0.2 seconds and about 0.8 seconds,   a second pipe connecting the upper part of the chamber to introduce the solid material into the chamber,   a third pipe connecting to the upper part of the chamber to introduce a pre-compressed fluid into the chamber,   a fluid valve connecting the third pipe to the upper part of the chamber wherein the fluid valve is configured to be selectively opened for a period less than about 0.4 seconds, wherein by rapidly and sequentially opening the exit valve and the fluid valve, the exit valve emits an impulsive flow of the solid material into the furnace.   
     
     
         15 . The injection device according to  claim 14 , wherein the impulsive flow of the solid material is higher than about 4 m/s. 
     
     
         16 . The injection device according to  claim 15 , wherein the impulsive flow of the solid material is higher than about 8 m/s. 
     
     
         17 . The injection device according to  claim 16 , wherein the impulsive flow of the solid material is higher than about 9-10 m/s. 
     
     
         18 . The injection device according to  claim 14 , wherein the opening period of the fluid valve is less than about 0.3 seconds. 
     
     
         19 . The injection device according to  claim 18 , wherein the opening period of the fluid valve is less than about 0.2 seconds. 
     
     
         20 . The method according to  claim 14 , wherein the pressure of the pre-compressed fluid is higher than about 5 bar. 
     
     
         21 . The method according to  claim 20 , wherein the pressure of the pre-compressed fluid is higher than about 7 bar. 
     
     
         22 . The method according to  claim 21 , wherein the pressure of the pre-compressed fluid is higher than about 8-10 bar. 
     
     
         23 . The method according to  claim 14 , wherein the flow rate of material emitted is higher than about 2 kg/s. 
     
     
         24 . The method according to  claim 23 , wherein the flow rate of material emitted is higher than about 3 kg/s. 
     
     
         25 . The method according to  claim 24 , wherein the flow rate of material emitted is higher than about 4-5 kg/s. 
     
     
         26 . The method according to  claim 14 , wherein the opening period of the exit valve is between about 0.3 seconds and about 0.7 seconds. 
     
     
         27 . The method according to  claim 26 , wherein the opening period of the exit valve is between about 0.4 seconds and about 0.6 seconds. 
     
     
         28 . The injection device according to  claim 14 , wherein the chamber is aligned axially to the first pipe. 
     
     
         29 . The injection device according to  claim 14  wherein further comprising an entering valve connecting the second pipe to the upper part of the chamber. 
     
     
         30 . The injection device according to  claim 14 , wherein the upper part of the chamber directly connects to the second pipe so that the solid material is directly introduced into the chamber at a pressure between about 1 bar and about 2 bar. 
     
     
         31 . A method for injecting a discrete amount of solid material in particle, powder or granulated form, comprising
 mounting a first pipe through a lateral wall of a melting furnace, wherein the melting furnace has walls defining a liquid metal retaining area, the first pipe has a lower end and an upper end, the the lower end of the first pipe is disposed inside the furnace and configured to be above a meniscus of liquid metal contained within the liquid metal retaining area,   connecting the upper end of the first pipe to a lower end of a chamber via an exit valve, wherein the chamber is configured to store the solid material and has an upper part, the exit valve is configured to be selectively opened for a period between about 0.2 seconds and about 0.8 seconds,   connecting a second pipe to the upper part of the chamber to introduce the solid material into the chamber,   connecting a third pipe to the upper part of the chamber to introduce a pre-compressed fluid into the chamber via a fluid valve, the fluid valve is configured to be selectively opened for a period less than about 0.4 seconds, and   by rapidly and sequentially opening the exit valve and the fluid valve, the exit valve emits an impulsive flow of the solid material into the furnace.   
     
     
         32 . The method according to  claim 31  wherein further comprising a filling step comprising
 disposing the chamber aligned axially to the first pipe, 
 connecting the second pipe to the upper part of the chamber via a entering valve, 
 closing the exit valve, 
 opening the entering valve to feed the solid material into the chamber, and 
 closing the entering valve when the solid material in the chamber reaches its desired amount.