An electric arc melting furnace comprises a furnace shell (1) with an electrode (3) for melting scrap by heat of arc, an air blasting port (20) for blasting air, oxygen or oxygen-enriched air into the furnace shell (1) through an air control valve (19), a carbon blasted quantity indicator (CI) for measuring quantity of carbon to be charged into the furnace shell (1), a scrap charged quantity indicator (SI) for measuring quantity of the scrap charged into the furnace shell (1), an oxygen blasted quantity indicator (OI) for measuring quantity of oxygen blasted into the furnace shell (1) and an arithmetic processor (7) for computing quantity of air required for complete combustion of carbon monoxide (23) in the furnace shell (1) in response to measured value from the indicators (CI)(SI)(OI) to control a degree of opening of the air control valve (19). Air with quantity in proportion to the carbon monoxide (23) is blasted through the air blasting port (20), which enables control of combustion temperature in the furnace shell (1) and control of temperature in the scrap preheating device.
A fume extraction system includes a combustion zone coupled with an exhaust outlet of a furnace to receive an exhaust gas stream emerging from the furnace outlet during system operation, where the exhaust gas stream includes explosive gases that undergo combustion reactions within the combustion zone. A duct section is aligned downstream from the combustion zone to deliver the exhaust gas stream toward a venting outlet. A suction unit establishes a negative pressure within the system so as to draw the exhaust gas stream from the furnace outlet and through the fume extraction system during system operation. An exhaust damper is further provided within the system between the combustion zone inlet and the suction unit. A control system selectively controls the negative pressure applied to the furnace, combustion zone and duct section based upon a measured concentration of at least one gas constituent within the exhaust gas stream.
The present invention uses narrow-band monobit receivers after a digital filter bank to separate simultaneous signals in one channel. The invention improves the capability of wideband digital receivers.
An electric arc furnace comprises a closed melting vessel and includes means for charging metal to be molten into the melting vessel. At least one electrode extends into the melting vessel and generates an electric arc and forms a molten metal bath. At least one oxygen lance can be extended into the melting vessel for injecting oxygen into the molten metal bath and create a reaction where the carbon monoxide is generated. Gas is exhausted from the melting vessel and the carbon monoxide gas concentration of the exhaust gas is measured. A post combustion chamber receives the exhaust gas and provides post combustion of the exhaust gas. Post combustion oxygen is injected into the melting vessel in an amount sufficient to provide post combustion based on the amount of oxygen necessary for post combustion of the exhaust gas and the post combustion chamber.
An electric arc furnace includes a closed melting vessel and includes an opening that can be closed where metal to be molten is charged into the melting vessel. At least one electrode extends into the melting vessel and generates an electric arc and forms a molten metal bath. At least one oxygen lance can be extended into the melting vessel for injecting oxygen into the molten metal bath and create a reaction where the carbon monoxide is generated. Gas is exhausted from the melting vessel and the carbon monoxide gas concentration of the exhaust gas is measured. A post combustion chamber receives the exhaust gas and provides post combustion of the exhaust gas. Post combustion oxygen is injected into the melting vessel in an amount sufficient to provide post combustion based on the amount of oxygen necessary for post combustion of the exhaust gas and the post combustion chamber.
An oxygen injector for a post combustion system used in an electric arc furnace includes a housing formed of a concave configured front wall and a spaced rear wall. The housing has a width greater than the spacing defined between the front wall and spaced rear wall. An oval configured conduit wall is located medially in the housing and extends from the rear to front wall to form an oval configured oxygen chamber and a water chamber with the oxygen chamber bound internally by the conduit wall. Orifices are formed in the front wall within the oxygen chamber.
