COOLING OF SHEET MATERIAL

Abstract: Successive strips of sheet material are each loaded onto respective trolleys (3) so as to extend longitudinally thereon, and the trolleys (3) are each loaded into one end (10) of a gas cooling tunnel (8) in which they are conveyed one after the other laterally of themselves along the length of the tunnel (8) to the other end (11) thereof from which they are removed. The trolleys (3) run on rails (12) in the tunnel (8) which can be raised and lowered at each end (10, 11) to engage and disengage each trolley (3) and to incline the rails (12) so that the trolleys (3) run along them. The flow of cooling gas is in the opposite direction to the movement of the trolleys (3) through the tunnel (8).

Description: COOLING OF SHEET MATERIAL This invention relates to the cooling of sheet material in the form of an elongate strip, for example, a strip of sheet rubber produced by a mill. Various cooling systems are known including water cooling systems in which the sheet rubber is immersed in chilled water. However, the contact with the cooling water impairs the quality of the rubber. Air cooling systems are also known in which the sheet rubber is loaded onto a conveyor which indexes the sheet along the length of a cooling tunnel. However, this equipment is bulky and expensive. Batch cooling systems are also known in which articles such as bricks are loaded onto a series of trolleys which travel the length of an air cooling tunnel. An object of the present invention is to provide an improved batch cooling system for sheet material. This is achieved according to the present invention by providing a cooling system in which SUBSTITUTESHEET successive strips of sheet material are each loaded onto respective trolleys so as to extend longitudinally thereon, and the trolleys are each loaded into one end of a cooling tunnel in which they are conveyed one after the other laterally of themselves along the length of the tunnel to the other end thereof from which they are removed. The advantage of this system is that the tunnel need only be relatively short to accommodate a long length of strip sheet material. Further, preferably, each strip is cooled by air or other cooling gas which flows laterally across its width, thereby allowing uniform cooling of the strip. Preferably, the air flow is from said other end at which trolleys are removed to said one end at which trolleys are loaded so that cooling occurs more evenly with progressively cooler air throughout the tunnel. The invention will now be described by way of example with reference to the accompanying SUBSTITUTESHEET drawings in which: Figure 1 is a schematic plan of a cooling system according to the invention, Figure 2 is a side elevation of a trolley for use in carrying strip sheet material in the system of Figure 1, Figure 3 is a plan view of the rail system for carrying the trolleys laterally of themselves within the cooling tunnel in the system of Figure 1, and Figure 4 is a side elevation of the rail system of Figure 3. Rubber stock is mixed and blended in a mill 1 and then rolled into a strip of sheet material. A continuous conveyor 2 elevates the strip and discharges it off the end so that it falls onto a trolley 3 which is simultaneously moved forward so that the strip is draped over a series of cross bars 4 spaced along the length of the trolley (see Figure 2). The trolley is supported on a pair of SUBSTITUTESHEET fixed wheels 5 at one end and a pair of castors 6 at the other end so that it can be wheeled longitudinally and steered. Two pairs of wheels 7 on transverse axes are also provided on the underside of the trolley, but these are above the level of the wheels and castors 5, 6 and do not touch the ground. Their function will be described later. Successive trolleys 3 are each loaded with a strip of sheet material that is cut from a continuous strip produced by the mill 1. Typically, ten trolleys can be loaded in this way and each in turn during a continuous operation loaded into a cooling tunnel 8. The cooling tunnel 8 comprises an enclosure with a longitudinal side wall 9 having a loading entrance 10 at one end and an unloading exit 11 at the other end. The entrance and exit 10, 11 are each the width of a trolley. The enclosure itself is wide enough to accommodate a trolley's full length. A pair of rails 12 extend the full length of the enclosure and comprise a fixed central section 12', which is inclined downwards slightly from the entrance 10 towards the exit 11, and end sections 12" which are supported at each end of SUBSTITUTESHEET the central section 12' on a pair of pivot arms 13 so that each end section 12" can be independently raised and lowered. Pneumatic actuators 14 are connected to each end section 12" to control its vertical position. At the loading end, trolleys are wheeled into the enclosure over a loading floor 15 having recesses that receive the rails 12. Once in place over the loading floor, the end section 12" of the rails is raised to engage the transverse wheels 7 on the underside of the trolley so that the trolley is lifted off the floor 15 and runs laterally on the rails 12. Successive trolleys are loaded onto the rails in this way and each runs laterally and engages the last trolley to be loaded. Typically, ten trolleys can be loaded in this way in an enclosure 5 metres long. These trolleys run down the rails towards the unloading end because of the inclination of the rails 12. At the unloading end, an unloading floor 16 similar to the floor 15 is provided to receive each trolley as the end section 12" of the rails is lowered at this end to allow the trolley to be unloaded through the exit 11. SUBSTITUTE SHEET Cooling air is ducted into cooling tunnel 8 at the exit end of the enclosure and is extracted at the entrance end. Typically, the air flow is 4,000 cu.ft/minute and the air temperature increases 5°C from one end to the other. The cooling time in the tunnel is about 20 minutes. Once cooled, the strips are unloaded from the trolleys by a motorised take-off drum 17 as the trolley moves longitudinally. SUBSTITUTESHEET

Claims: CLAIMS 1. A cooling system comprising a plurality of elongate mobile trolleys (3) each adapted to support a strip of sheet material longitudinally thereon, a cooling tunnel (8) which is adapted to receive the trolleys (3) at one end (10) thereof and to have the trolleys removed from the other end (11) thereof, and which is adapted to pass a flow of gas therethrough to cool the strips of sheet material on the trolleys, and conveying means (12) which serves to move the trolleys from said one end (10) to the other end (11) of the tunnel, characterised in that the conveying means (12) is such that the trolleys (3) are arranged laterally of their direction of movement through the tunnel (8) . 2. A cooling system as claimed in claim 1 further characterised in that the conveyor means comprises rails (12) on which trolleys (3) are guided. SUBSTITUTE SHEET 3. A cooling system as claimed in claim 2 f rther characterised in that the rails (12) are adapted so that they can be raised and lowered at each end (10, 11) of the cooling tunnel to engage and disengage each trolley at said ends (10, 11). 4. A cooling system as claimed in claim 3 further characterised in that the rails (12) at each end (10, 11) are received in recesses in a floor (15) over which the trolleys run into and out of the cooling tunnel. 5. A cooling system as claimed in claim 4 further characterised in that the rails (12) cooperate with wheels (7) on the underside of the trolleys (3) which are clear of the floor (15). 6. A cooling system as claimed in any one of the preceding claims further characterised in that the rails (12) are inclined downwards from said one end (10) to the other end (11) to cause the trolleys to run along the rails (12). SUBSTITUTESHEET 7. A cooling system as claimed in any one of the preceding claims further characterised in that the cooling tunnel (8) is such that the flow of cooling gas is substantially along the line of movement of the trolleys (3). 8. A cooling system as claimed in claim 7 further characterised in that the cooling tunnel (8) is such that the flow of cooling gas through the tunnel is in substantially the opposite direction to the direction of movement of the trolleys (3) through the tunnel (8). 9. A method of cooling sheet material in the form of elongate strips comprising loading the strips onto elongate mobile trolleys (3) so as to extend longitudinally of the trolleys (3), and conveying the trolleys (3) through a cooling tunnel (8) which has a flow of gas passing through it to cool the strips, characterised in that the trolleys (3) are arranged laterally of their direction of movement through the tunnel (8). SUBSTITUTE SHEET 10. A method as claimed in claim 9 further characterised in that the flow of cooling gas through the cooling tunnel (8) is substantially along the line of movement of the trolleys (3). 11. A method as claimed in claim 10 further characterised in that the flow of cooling gas through the cooling tunnel (8) is in substantially the opposite direction to the direction of movement of the trolleys (3) through the tunnel (8). 12. A cooling system substantially as herein described with reference to the accompanying drawings. 13. A method of cooling sheet material in the form of elongate strips substantially as herein described with reference to the accompanying drawings. SUBSTITUTESHEET

Inventors: MONKS JEFFERY ANDREW, MONKS, JEFFERY, ANDREW
Applicants: DOWTY SEALS LTD, DOWTY SEALS LIMITED
Application year: 1990
Main classification: F26B15
IPC codes: B29C35, F25D13, F26B15