Electric heating – Heating devices – Combined with container – enclosure – or support for material...
Patent
1995-05-11
1997-03-11
Walberg, Teresa J.
Electric heating
Heating devices
Combined with container, enclosure, or support for material...
432202, 266121, F27B 912, F27B 936
Patent
active
056097859
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to a method for heating metal slabs in an elongated heating furnace. The invention relates also to an elongated heating furnace for heating metal slabs.
The purpose of heating metal slabs is to bring about a proper temperature for metal slabs to be rolled or otherwise moulded. For example, steel slabs are heated prior to a rolling operation to the temperature of appr. 1100.degree.-1200.degree. C. in order to make them sufficiently mouldable. For heating, the slabs are carried into a heating furnace by means of suitable equipment. The heating furnace is an elongated and usually a brickmasoned structure which is heated with suitable burners. The temperature profile of a heating furnace is selected to be such that, upon leaving the heating furnace, the slabs have a desired temperature. In this context, the term temperature profile is defined as referring to the temperatures of the furnace and slabs contained in the furnace at a certain instant of time. The furnace has its own temperature profile. Respectively, the slabs have their own temperature profile at each point in the direction of thickness. Thus, if the temperature profile of a heating furnace is known, the temperature at each point within the furnace is also known. If the temperature profile of a certain point, e.g. that of the surface of a slab, is known, the surface temperature of the slab will be known at each point in the longitudinal direction of the heating furnace.
A typical heating furnace for metal slabs is divided into three zones, the first zone being a so-called convection zone which is the first to take up the slabs. This is followed by a so-called heating zone which accommodates burners operating on a fossil fuel, i.e. gas or oil. The final zone in the traveling direction of the slabs is a so-called equalizing zone, wherein temperature of the slabs is allowed to equalize. The heating furnace operates in a manner that the combustion gases from burners firing in the heating zone are conveyed upstream relative to the traveling direction of the slabs from the heating zone to the convection zone. Thus, the burners are located in the rear section of the heating zone and a chimney in the front section of the convection zone. With an arrangement like this, a temperature difference between the combustion gas and the slab is significant at each point in the lengthwise direction of a furnace so as to provide a heat transfer as effective as possible from combustion gas to slab. In the convection zone, the transfer of heat from combustion gas to slab occurs through convection, as suggested by the name of this zone.
U.S. Pat. No. 4,299,565 discloses a heating furnace wherein metal slabs are heated by fuel combustion flames. Heat transfer converters each made of a heatresistant material are disposed downstream of the flow of the combustion flames in the convection zone of the furnace. These converters are heated through convection heat transfer from a high temperature and high speed flow of the combustion flames and combustion gas. The purpose of the converters is to raise the thermal efficiency of the furnace by utilizing the heat that otherwise would be lost along with the discharging combustion gases.
Patent application GB 2 048 440 discloses a heating furnace for metal slabs, wherein the metal slabs are heated by using a plurality of burners and radiant heaters located one below another and at equal distances over the entire furnace length. The cited heating furnace is primarily intended for use in the bright annealing of copper under a shielding atmosphere. In bright annealing, a copper product is heated in a reducing atmosphere for removing an oxide layer from the product surface and for producing a bright surface. The purpose of the burner is not only the production of heat but also the production of a reducing atmosphere. The fuel comprises e.g. natural gas or other pure hydrocarbon and the combustion is effected with depleted oxygen for the production of reducing gases, such as carbon
REFERENCES:
patent: 4125365 (1978-11-01), Nelson
patent: 4229163 (1980-10-01), Shinohara
patent: 4266932 (1981-05-01), Shinohara
patent: 4299565 (1981-11-01), Shinohara
patent: 4388068 (1983-06-01), Takeuchi et al.
patent: 4745252 (1988-05-01), Roth et al.
patent: 5156800 (1992-10-01), Buchet et al.
Mantyla Pekka
Sallinen Johannes
Acon Finland Oy Ltd.
Rautaruukki Oy
Walberg Teresa J.
LandOfFree
Method and apparatus for improving the performance of a heating does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for improving the performance of a heating , we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for improving the performance of a heating will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-440750