GB2301660A

GB2301660A - Buffer furnace

Info

Publication number: GB2301660A
Application number: GB9611433A
Authority: GB
Inventors: Ralph Gladwin Haynes
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-06-01
Filing date: 1996-05-31
Publication date: 1996-12-11
Anticipated expiration: 2016-05-31
Also published as: GB2301660B; GB9611433D0

Abstract

A furnace capable of storing a plurality of elongate workpieces 5 comprises a first 1 part with a plurality of fixed horizontal shelves 3 in uniform vertical spaced apart relation. A second part has a plurality of fixed horizontal shelves but with the shelves 3 movable in unison relative to the shelves of the first part. Entry 7 and exit 15 means by which the workpieces enter and then leave the furnace are provided, one in each of the two parts of the furnace.

Description

ImProvements In Furnaces This invention relates to furnaces and in particular to furnaces in which a plurality of elongate metal workpieces can be stored. A particular application of the invention is to a furnace in which a plurality of elongate metal bars or slabs produced in a continuous caster can be accommodated whilst awaiting their turn to be rolled in a hot strip rolling mill.

It is known to produce steel bar or slab from molten metal in a continuous caster and for the bar or slab to be rolled into metal strip. It is usual to shear the bar or slab into convenient lengths and for each length in turn to be rolled in the rolling mill. To obtain strip of satisfactory uniform quality it is necessary to ensure that the temperature of the bar or slab is substantially uniform along its length and at a predetermined rolling temperature before it enters the rolling mill. It is usual therefore to retain each length of bar or slab in a furnace to allow its temperature to equalise along its length to the predetermined value before the bar or slab enters the mill.

If the casting rate is greater than the rolling rate for any significant period of time, some form of buffer has to be provided to accommodate the lengths of cast bar or slab as they wait their turn to be rolled. Particularly, if the rolling mill is stopped for maintenance or due to a fault, it is essential to provide a buffer so that the casting does not have to be stopped. Since it is important that the cast bar or slab does not lose too much heat before it enters the rolling mill, it is convenient to make the furnace also serve as a buffer.

According to the present invention a furnace capable of storing a plurality of elongate workpieces comprises first and second parts each having a plurality of horizontal shelves therein, the shelves being arranged in uniform vertical spaced apart relation and each being able to accommodate an elongate workpiece, the corresponding shelves of the two parts being alignable in end-to-end relation and means for raising and lowering the shelves of the second part in unison relative to the shelves of the first part by a distance equal to the vertical separation of the shelves, entry means in one part by which workpieces enter the furnace and exit means in the other part by which the workpieces leave the furnace.

It is convenient for each part of the furnace to comprise a housing with the horizontal shelves fixed therein, an open end of one of the housings being in communication with an open end of the other housing and the housing of the second part being raised and lowered with the shelves therein.

In order that the invention may be more readily understood it will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a sectional side elevation of a furnace in accordance with the invention; and Figure 2 is a chart showing operation of the furnace shown in Figure 1.

A furnace comprises a fixed housing 1 having a plurality of horizontal shelves 3 arranged in it. Each shelf is of a length capable of supporting an elongate workpiece 5 and the shelves are located in uniform vertical spaced apart relation. An inlet 7 at the left hand end of the fixed housing is aligned with the lowest shelf 3 in the housing.

The right hand end of the fixed housing is open and is in communication with the open left hand end of a movable housing 9 which also has horizontal shelves 3 in it. The shelves can be aligned with the corresponding shelves in the fixed housing 1 and each shelf can accommodate an elongate workpiece 5. The shelves 3 in the two parts of the furnace comprise a multiplicity of rollers arranged with their longitudinal axes horizontal and some of the rollers of each shelf are driven by means not shown.

The movable housing 9 with the shelves 3 in it can be raised and lowered relative to the fixed housing by means of a lifting device 11 acting on the underside of the housing.

The device 11 conveniently comprises a plurality of hydraulic means 13 acting against a foundation and the floor structure of the housing. An outlet 15 at the closed end of housing 9 is aligned with the upper shelf. Means (not shown) are provided in both housings to keep the temperature of workpieces stored therein at a predetermined level.

As an alternative, the housing 9 could be fixed but with the shelves 3 raised and lowered in unison relative to the fixed housing by means of the lifting device 11.

Operation of the furnace is shown in Figure 2.

Referring to the figures, a workpiece such as a cast bar or slab 5 passes through a shear 17 and is cut to a required length. This length continues through the entry inlet 7 and comes to rest on the lowest shelf 3 of the fixed housing.

It is then displaced by the rollers to the lowest shelf of the movable housing 9. [Figure 2.2].

The lifting device 11 is then operated to raise the shelves in the movable part by a distance equal to the vertical separation between the shelves [Figure 2.3). The workpiece 5 is then driven back to the second lowest shelf in the fixed housing [Figure 2.43. At the same time, the next workpiece 5A is entering the lowermost shelf of the housing [Figure 2.5). Both of the workpieces 5.5A are then driven to the corresponding shelves in the movable housing which has been lowered back to its original position [Figure 2.6).

Figure 2.7 shows the shelves of the movable housing raised relative to those in the fixed housing and the workpieces are moved back into the fixed housing as shown in Figure 2.8.

The sequence of operations is continued until workpieces 5,5A are located on the upper two shelves respectively of the fixed part of the furnace as shown in Figure 2.12. At the same time one or more additional workpieces are allowed to enter the furnace until 50-60% of the shelves in the fixed part of the furnace accommodate a workpiece. During their stay in the furnace the temperature of each workpiece is being equalised along its length and it is being raised to the required rolling temperature. The workpiece 5 on the uppermost shelf in the furnace is now ready for rolling. The movable part of the furnace is lowered to its original position and the workpieces in the shelves of the fixed part are transferred to the corresponding shelves of the movable part and the workpiece 5 is driven out of the exit 15 of the furnace and into the stands of the finishing mill. At the same time a new workpiece 5B is entering the furnace [Figure 2.14].

After the furnace has 50-60% of its shelves accommodating workpieces, it is desirable that each time a workpiece leaves the furnace to be rolled another workpiece enters the furnace. If for any reason the rolling mill is stopped and workpieces cannot be taken from the furnace, the furnace can still accommodate additional workpieces from the caster for a period of time before casting has to be stopped. In most cases of mill maintenance or roll change the furnace can accommodate all the incoming workpieces.

Claims

Claims:

1. A furnace capable of storing a plurality of elongate workpieces comprising first and second parts each having a plurality of horizontal shelves therein, the shelves being arranged in uniform vertical spaced apart relation and each being able to accommodate an elongate workpiece, the corresponding shelves of the two parts being alignable in end-to-end relation and means for raising and lowering the shelves of the second part in unison relative to the shelves of the first part by a distance equal to the vertical separation of the shelves, entry means in one part by which workpieces enter the furnace and exit means in the other part by which the workpieces leave the furnace.

2. A furnace as claimed in claim 1 in which each part of the furnace comprises a housing with the horizontal shelves fixed therein, an open end of one of the housings being in communication with an open end of the other housing and the housing of the second part being raised and lowered with the shelves therein.

3. A furnace as claimed in claim 2, in which the entry means and exit means to the furnace are aligned with the lowermost shelf of the first part and the uppermost shelf of the second part respectively.

4. A furnace substantially as hereinbefore described with reference to the accompanying drawings.