DE1046083B - Method and device for heating continuous ovens for billets or the like. - Google Patents

Description

Method and device for heating continuous furnaces for billets or the like. When heating rolled stock, it is of minor importance whether the Well heated evenly or unevenly in the preheating oven. Matters only that the material at the end of the preheating zone is practically uniform, up to in the core, is heated.

In the continuous furnaces previously used for the heat treatment of metals, z. B. Billet pusher ovens, the oven space is usually in one for preheating the material serving shock hearth and a welding hearth serving as a glow space divided. So far the preheating of the material in such bfen using the exhaust gases from the welding hearth happened, these gases were hitherto in countercurrent to the one wandering through the shock source Well managed.

In a furnace in which the heating gases flow in countercurrent to that to be heated However, it cannot be achieved that the material is at the end of the preheating zone until the core is practically evenly heated, as there is always a temperature gradient must exist between good and heating gas in order to be able to operate during the preheating time to be able to heat the goods to the desired temperature. But then there is also at the end of the preheating room, a temperature gradient between the outer zone and the core of the pieces to be preheated.

This unevenness of heating over the entire cross-section of the warm goods makes the exhaust gas countercurrent preheating for many types of goods, in particular Stainless steels, unsuitable. Often it is even necessary to achieve the good at one Preheating temperature, e.g. B. 700 ° C, stand in the preheating room (shock stove) for a short time to allow full thermal penetration of the pieces at this temperature takes place and only then the material in the annealing room quickly to the appropriate rolling temperature bring to.

The invention achieves that the material at the end of the preheating zone until the core is practically evenly heated.

According to the proposal, the exhaust gas from the glow chamber is mixed in with its temperature influencing gases to a temperature suitable for preheating brought and this gas mixture then in cocurrent ini t the material through the preheating room guided.

According to the invention, the exhaust gas from the preheating zone serves as additional gas. In its place or as an additive, exhaust gas or gas from another source can also be used be used. Amount and temperature of that flowing through the E'orv; ärmraum Gas mixtures can thus be measured and regulated according to the respective requirements will.

By passing through the furnace in cocurrent with the material to be heated With hot gases, the goods are suddenly exposed to a high temperature. There is a large temperature gradient between heating gas and goods as well as between the outer zone of the individual pieces and their core. This makes the good very quickly on a proportionate basis heated high temperature. This decreases on the further way through the furnace Temperature gradient between the heating gas, the outer zone of the individual pieces and their core more and more until it is so low at the end of the preheating zone that it is practical is meaningless. At the end of the preheating room are the good pieces if the heating gases are passed through the furnace in cocurrent with the material to be preheated until in practically evenly heated the core, as has been determined by experiments. the Good pieces prepared in this way can then be passed through the following in the glow chamber The effect of high temperatures is quickly brought to the required rolling temperature will.

To carry out this process, the exiting from the glow chamber is used Exhaust gas withdrawn from the glow room at the transition point from the glow space to the preheating space and with the exhaust gases entering from the preheating room at the same transition point mixed. The two exhaust gas flows can be combined with their full exhaust gas quantities or only partial amounts of the two types of exhaust gas are mixed with one another. Possibly can also be another one that lowers the temperature of the exhaust gases from the same zone, suitable gas of any origin can be added. Depending on the quantity required of preheating gas and the desired temperature in the preheating room, the entire from both stove parts resulting amounts of exhaust gas or partial amounts of these for the Gas mixture flowing through the preheating chamber.

The gas mixture thus obtained, which has a certain temperature, e.g. B. 750 ° C, becomes the entry end of the preheating room and introduced into it as heating gas. It flows through the warming room in direct current with the goods wandering through this space. At the transition point from Before warming to the glowing room, mixing takes place again with that from the glowing room escaping exhaust gas. This creates a heating gas cycle in the preheating room, which is supplemented by constantly new hot exhaust gas. A subset of the The resulting total amount of gas is withdrawn from the circuit.

By optionally mixing larger or smaller proportions of the two Exhaust gas flows with one another can be used to determine the amount and temperature of the preheating gases adapt to the respective requirements.

The routing of the preheating gas mixture to the inlet end of the preheating room takes place outside the preheating room. However, this guidance is expedient in the furnace body near below the preheating stove. So the warmth of the gases comes to that Preheating room benefit; the stove top and the good pieces are even from below warmed up.

To mix the two exhaust gas streams, a special one, if necessary outside of the oven space arranged mixing chamber can be provided. The cliung can, but also in the guide channel located below the hotplate of the preheating space take place, if necessary a special one when entering this channel Mixing space for the gas mixture to be produced can be arranged.

It is known to be useful for heating the input material To achieve temperature distribution in the furnace, the combustion media are part of the furnace exhaust gases to add.

It has also been suggested for ovens with two or more Zones of different temperature the furnace exhaust gases through at the dividing points of the zones and, if necessary, inflow openings provided within one of these zones so strong pressure that the furnace zones without the arrangement of separating devices are sharply separated from each other.

Another suggestion is to use the Heating gases above the introduced goods in direct current and below the goods in countercurrent to the material through the furnace.

The advantages achieved by the invention can be however, this method does not achieve this.

The drawing illustrates an embodiment of one for implementation the billet pusher furnace designed according to the method according to the invention.

Fig. 1 shows a vertical longitudinal section through the furnace, Fig.2 a horizontal section through the stove with a top view of the stove.

The furnace used to heat billets is in preheating room 1 and the glow space 2 is divided. The oven goods are introduced into the oven at 3 and after wandering through the furnace chamber through the openings 4 brought out of the furnace.

On their way through the preheating room 1, the billets are pushed, moved on because paths through the glow chamber 2 by means of a walking beam. By In the event of an emergency, a number of sticks can be dropped into the collecting system 5 be withdrawn from the glowing room temperature.

The glow space 2 is lit with the aid of the burner 6. That in the glow space 1 exhaust gas occurs at the transition point 7 from the glow space to the preheating space.

Below the preheating stove, extending over its position, there is a gas duct 8, which is in open connection with the preheating stove at its end facing the transition point 7 via the duct 9 and at its end facing the material inlet 3 via the duct 10. A fan 11 is arranged in channel 8 when it crosses into channel 10. With the aid of the fan 11, a gas cycle is brought about through the channels 9, 8, 10 and the preheating chamber 1. Furthermore, the channel 10 is in open connection with the kauchkana112 at the bottom. In addition, an exhaust gas outlet via the channel 13 and flue gas channel 14 is provided at the transition point 7. The train in the flue gas duct 14 can be regulated with the aid of the slide 15, and in the flue gas duct 12 with the aid of the slide 16.

The exhaust gas entering the preheating chamber 1 at 7 from the glow chamber flows through the channels 9, 8, 10 and the with the help of the energy of the fans 11 Preheating space 1 in the circuit and gives its sensible heat to the flow material away. In the continuous furnace operation, the hot overflow from the glow chamber becomes hot Exhaust gas in channels 9 and 8 mixed with cooled exhaust gas from the preheating chamber and thereby influences the temperature of the gas sweeping the preheated material.

The proportions of the hot exhaust gas to be added to the preheating gas at 9 are from the glow chamber 2 by actuating the slide 15 and thus by diverting a part of the hot exhaust gas through the channels 13 is determined. The amount required Preheating gas is by actuating the slide 16 and thus by deriving a Partial amount of the preheating gas regulated through channels 10 and 12.

Claims (10)

PATENT CLAIMS: 1. Method for heating conveyor ovens for the Heat treatment of billets or the like with subdivision of the hearth space into a glow space and a preheating room as well as heating of the preheating room by the exhaust gases from the glowing room, characterized in that a mixture of exhaust gases from the glow space (2) and exhaust gases from the preheating room (1) in cocurrent with the migrating material through the preheating zone to be led. 2. The method according to claim 1, characterized in that the entire Exhaust gases from the glow space at the transition point (7) between the glow space (2) and preheating space (1) deducted and in full or in part with the full or part of the Preheating chamber exhaust gas are mixed. 3. The method according to claim 1 and 2, characterized characterized in that the exhaust gas of the glow chamber (2) also has another temperature regulating gas is added. 4. The method according to claim 1 to 3, characterized in that that the gas mixture is close below the preheater along to the point of introduction is fed into the preheating stove. 5. The method according to claim 1 to 4, characterized in that that the mixture of the two types of exhaust gas at the transition point (7) from the glow space (2) and preheating space (1) takes place by the confluence of the two gas streams. 6. Procedure according to claims 1 to 5, characterized in that the mixture of the two types of exhaust gas in a mixing chamber arranged outside the oven space is carried out. 7. Establishment for carrying out the method according to claim 1 to 6, characterized by a below the preheating over its length extending channel (8), the at its end towards the transition point (7) via a channel (9) and at its end to the material inlet (3) via a channel (10) with the Preheating space (1) is in open connection. B. Facility for carrying out the Method according to claim 1 to 6 and also according to claim 7, characterized by Arrangement of a fan (11) at the transition to the one below the preheating stove Channel (8) into the transfer channel (10) to the preheating space located at the material inlet (3) (1). 9. Device for performing the method according to claim 1 to 6 and according to Claim 7 and 8, characterized by an exhaust gas discharge duct (13, 14) from the transition point (7) to the chimney. 10. Device for carrying out the method according to claim 1 to 6 and according to claim 7 to 9, characterized by a closable exhaust gas discharge duct (10, 12) at the end of the diversion duct (8) arranged below the preheating stove. References considered: U.S. Patent No. 1530,239; German patent applications p 31330 VI a / 18 c D (published April 19, 1951); B 2798 VI / 18 c (announced on June 11, 1952).