DE2658867A1 - INDUSTRIAL FURNACES, IN PARTICULAR LIFTING FURNACES - Google Patents

Description

KLÖCKNER-WEBKE AKTIENGESELLSCHAFT, Mülhe. \ Mer Str. 50, 41 Duisburg Λ

Industrial furnace, especially lifting hearth furnace

The invention relates to an industrial furnace, in particular a lifting hearth furnace, with components through which a coolant flows.

Lifting hearth furnaces, also known as walking beam furnaces, are used to heat slabs, plates, sheets, etc. for further processing. Here, for example, the slab is through repeated lifting, advancing and lowering in the longitudinal direction promoted by the furnace. Serve for lifting and anterior Movable components that can be put together to form pairs of walking beams and alternately open the slab in the furnace set down the stationary components.

A coolant flows through these components, both the movable and the fixed, with cold water cooling generally being used and the movable cooling elements being connected to the fixed line system via flexible hose connections. With cold water cooling, the heat dissipated with the water is lost. Hot cooling systems are also known, the cooling heat being advantageously used. Here, the treated cooling water is passed through these components and other parts to be cooled, for example door frames, for example in a cooling circuit under a pressure of 32 bar with a boiling temperature of 280 ^° C. in forced circulation from a steam drum, with part of the water evaporating. The steam-water mixture enters the steam drum

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back where water and steam separate. The water will fed back into the cooling system, while the steam is fed into the works network. One that corresponds to the amount of steam The amount of treated boiler feed water must be fed back into the steam drum.

The movable cooling elements are in this case via drilling swivel joints hinged to the fixed pipe system. The disadvantage of this solution is that the high Pressures and temperatures, sealing difficulties occur at the Eohr swivel joints. In addition, each The static friction to be overcome with each movement section puts the sealing material under extreme stress.

The invention is based on the object of industrial furnaces to be designed in such a way that, on the one hand, the advantages of hot cooling (use of cooling heat) and, on the other hand, the problem-free hose connections for cold water cooling can be used.

This object is achieved in that the movable components and the fixed components are each arranged in a separate cooling circuit and the coolant seal and temperatures in the cooling circuit for the movable elements are kept lower than those of the cooling circuit for the fixed components. This is based on the knowledge that at constant pressure the enthalpy increase of the coolant does not increase in temperature as long as all the liquid does not evaporate. According to the invention, the pressures and temperatures of the cooling

means so low in the circuit for the moving elements,

that there are no problems with the hose connections and operational safety is guaranteed. The high pressure required for a steam consumer is run in the second fixed cooling circuit. Every cycle works here according to the invention with its own circulation pump.

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Klöckner-Werke AG file 174-8

In an advantageous development of the invention, the cooling circuit for the fixed components is also included fed by the water / steam mixture of the cooling circuit for the movable components. Through these measures takes place Compensation for the amount of steam released by the cooling circuit for the fixed components to the plant network, a corresponding amount of feed water is fed into the cooling circuit for the movable components.

Advantages and features of the invention are explained in more detail using an exemplary embodiment in the drawing.

Show it:

Fig. Λ a lifting hearth furnace in cross section in schematic

table representation 5

2a, 2b a swivel joint for a movable component in a schematic representation}

3 shows the block diagram of the exemplary embodiment.

In Fig. 1, 1 denotes a walking beam furnace in cross section. The slab 2 to be heated is within the off refractory material existing and heated chamber 3 arranged, in which, for the sake of clarity, the burners for the heating gas are not shown. In the bottom of the chamber are those fixed structural elements 4, and protrude into the tree 5 by the arrows 6 and 7 is shown schematically, that the stationary components are traversed by a coolant. They are used in their entirety as a fixed hearth designated. The bottom of the chamber has through openings which guide the movable components 8. You are on The lower end is arranged in a movable frame that moves in the direction perpendicular to the plane of the drawing can be that thereby lifted the slab, proceed

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and can be lowered back onto fixed components. In this way the slab is moved in time to the outlet of the lifting hearth furnace.

The entirety of the movable components, including the transport systems connected to them, is considered to be movable Called stove. A coolant also flows through the movable components. This is shown schematically by arrows 9 and 10. The movable component designated by 11 is shown in section and shows the direction of coolant flow.

The piping system for the fixed stove and the movable stove is housed in room 5 and for the sake of clarity not shown for the sake of

In Fig. 3, the movable cooling elements are denoted by 8 and the fixed cooling elements by 4, the schematic are grouped together for a better overview. The movable connections of the cooling elements 8 hose connections 15 and 16 are shown in their associated cooling circuit. These hose connections are much simpler than the tube swivel joints in Fig. 2. Via a check valve 17, the feed water fed to the cooling system for the movable components. In line 18 between these check valves i? "and the hose connections 15, the pressure control valve 19 is arranged, the pressure in the part of the circuit that is provided with hose connections, keeps constant at a relatively low value. A circulation pump 20 provides for maintaining the coolant flow in this circuit via a throttle 21 and for the purpose of being more effective Cooling for a high flow rate of the cooling water. On the other hand, the circulation pump 20 promotes that in the cooling elements 8 resulting water / steam mixture as required

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Via a control valve 22 into the steam drum 23 of the cooling circuit of the fixed hearth. The control valve 22 is part of the water level control of the steam drum 23- In the cooling circuit of the plague stove, which is maintained by means of circulation pumps 24 is, the cooling elements 4, in which steam is generated. In the steam drum 23, saturated steam escapes from the Water / steam mixture, which is fed to the plant network via a pressure control valve 26 and steam superheater 25.

In Fig. 2a is a known pipe swivel joints 12, 13, 14 made connection for a movable component on the cooling system, showing the intricacy of such connections. The arrows indicate the direction of flow of the coolant. Fig. 2b shows the movement diagram of the tube swivel joints during the transport of a slab to the next heating station in a walking beam furnace.

The scope for interaction between the two cycles lies between the enthalpy of the feed water and the enthalpy of the steam at a pressure of 3 bar. This means that the heat access in the two circuits may be different and their relationship to one another is allowed to change. This is the interaction of the cooling circuits and the balance the heat transfer in both parts is possible in the manner according to the invention.

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Claims (2)

- it - Klöckner-Werke AG Act 1--48 Expectations \\ jt Industrial furnace, in particular lifting hearth furnace with components through which a coolant flows, characterized in that the movable components (8) and the fixed components (4-) are each arranged in their own cooling circuit and the coolant pressures and temperatures in the cooling circuit for the movable elements are kept lower than those of the cooling circuit for the fixed components. 2. Industrial furnace according to claim 1, characterized in that the cooling circuit for the fixed components is fed with the water / steam mixture of the cooling circuit for the movable components. 809826/0381 OR / _{G / NAL}