MXPA97007637A - An ac transfer system - Google Patents

Abstract

The present invention relates to a heat transfer system in which a continuous mesh of material is carried beyond a surface of the hot plate with one face of the mesh in contact therewith, there being means applying a load on the opposite face of the mesh to maintain said contact between the mesh and the surface of the hot plate, and transport means to transport the mesh beyond the surface of the plate, wherein the means of application of the load are static and in contact direct sliding surface with the mesh as it is transported beyond the surface of the hot plate and where the means of transport are arranged completely beyond the surface of the hot plate in the direction of transport of the wrong

Description

A SYSTEM OF HEAT TRANSFER This invention relates to heat transfer systems in which a continuous mesh of material must be transported across the surface of one or more hot plates whereby the mesh is subjected to said elevated temperature for a period of time. determined period.

Particularly, although not exclusively, the invention relates to corrugation machinery in which a continuous mesh of single-sided corrugated cardboard with glue applied to the exposed tips of the corrugated sheet is attached to a liner which is therefore bonded to the tips with glue to form a double-sided board and the mixed board is carried back from a bank of heaters that help in the union of the lining to the corrugated tips of the board of a single face. A system of this kind usually incorporates means to impose a load on the opposite face of the mesh from that which is in contact with the heaters to thereby maintain uniform contact between the board and the hot surface, in order to ensure heat transfer adequate Therefore, with such equipment, there is a tendency for the hot plate surfaces to deform, the load application means being designed so as to have a flexible surface such that the mesh is maintained at a substantially uniform pressure on all its width against the surfaces of the hot plate as it travels through the system. Various different arrangements have been proposed for this purpose such as fluid-filled containers and spring-loaded or pivotal shoes. In order to transport the mesh over the hot plates, a pulling device is provided consisting of a pair of pull bands disposed respectively on opposite faces of the mesh. The upper traction band usually carries the mesh through the heat transfer system and therefore travels with the mesh on the hot plate surface. This leads to using the upper traction band as it passes through the heating section, particularly when the band is wider than the mesh and therefore in its regions of the edge is in sliding contact with the hot surface. Patent specification FR 1351264 describes a system which attempts to avoid excessive wear of the pull band by replacing it with a downwardly held cap which maintains pressurized air on the upper surface of the mesh as it travels over the hot surface. However, this system suffers from a disadvantage that it can not maintain sufficient pressure particularly when the mesh is formed of lightweight papers. A further disadvantage is that the cap traps moisture inside the mesh. Therefore a more positive downward maintained system is required but one that avoids excessive wear of the means to provide traction for the mesh to pass over the hot surface.

According to the present invention there is provided a heat transfer system in which a continuous mesh of material is carried after a hot plate surface with one face of the mesh in contact therewith, having means imposing a load on the opposite face of the mesh to maintain said contact between the mesh and the surface of the hot plate and conveying web means to transport the mesh after the surface of the hot plate; characterized in that the means applying the load are in direct contact with the mesh as it travels after the surface of the hot plate, and in that the conveying means are disposed completely beyond the surface of the hot plate in the direction of the transport of the mesh. Preferably, the transport means comprises a pair of traction bands disposed respectively on opposite faces of the mesh, each of said strips being disposed completely beyond the surface of the hot plate in the direction of transport of the mesh. One embodiment of the invention will now be described, by way of example only, with reference to the accompanying schematic drawing illustrating a heat transfer system made in accordance with the invention. The system comprises a heating section 10 and a transport section 11. The heating section 10 comprises a bank or series of heating drawers having a common upper hot plate surface 12. In this example, a single corrugated board with one single face 13 is fed to the left or input end of the transfer system as illustrated in the drawing, having an adhesive applied to the corrugated tips of the board that must be combined with a flat sheet of the liner 14 and transported through the hot plate surface 12 so that the adhesive can be cured. Located above the heating drawers is a series of fluid filled containers 15 a combined end of which is to apply a substantially constant load on the double sided board thus holding it firmly down against the hot plate surface of the heating drawers without consider any ripple thereof, so as to transfer heat substantially uniformly to the board. The double-sided board is transported beyond the heating drawers by the traction section 11 which effectively consists of a pair of traction bands 16 and 17 arranged respectively on the upper and lower faces of the board and these are driven by a system of common drive to thus transport the board at a substantially uniform speed through the system. Beneath the lower band 17 there is a fixed platform 18 on which the band travels and above the upper band 16 there is a short series of fluid-filled containers 19 similar to the containers 15 in the heating section 10. These containers 19 they serve to maintain adequate impulse contact between the bands 16 and 17 and the corrugated board. By placing both upper and lower traction bands completely beyond the heating section 10 this serves to minimize the wear of the web, and, when compared to a known system in which a superior traction web also passes through. of the heating section, not only band wear is reduced further but the length of the upper band is also reduced by minimizing manufacturing costs to a minimum. It is not intended to limit the invention to the previous example. In particular, fluid filled containers 15 can be replaced by a flexible axle surface of, for example, pivoted or spring-loaded individual shoes, the overall purpose of which is to maintain uniform contact between the mesh and the hot surface.

Claims (6)

1. CLAIMS 1. A heat transfer system in which a continuous mesh of material (13, 14) is carried beyond a surface of the hot plate (12) with one face of the mesh in contact therewith, having (15) applying a load on the opposite face of the mesh to maintain said contact between the mesh and the hot plate surface and conveying means (16, 17) to transport the mesh past the surface of the plate; characterized in that the means for applying the load (15) is in direct contact with the bad (13, 14) as it is transported beyond the surface of the hot plate (12) and in that the means of transport (16). , 17) is disposed completely beyond the hot surface (12) in the transport direction of the mesh.
2. 2. A heat transfer system according to claim 1, wherein the transport means comprises a pair of traction bands (16, 17) disposed respectively on opposite sides of the mesh (13, 14), each of said bands being arranged completely beyond the hot plate surface (12) in the transport direction of the mesh.
3. 3. A heat transfer system according to claim 1 or claim 2, wherein the means for applying the load comprises a series of containers filled with fluid (5) adapted to apply a substantially constant load on the mesh (13). , 14) thus holding down firmly against the surface of the hot plate (12) without considering any ripple thereof.
4. 4. A heat transfer system according to claim 2, wherein the traction bands (6, 17) disposed respectively on the upper and lower faces of the mesh (13, 14) are driven by a common drive system arranged to transport the mesh through the system at a substantially uniform speed.
5. 5. A heat transfer system according to claim 4, including a fixed platform (18) located below the bottom of said traction bands (17) and on which the web travels and one or more filled containers of fluid (10) located above the top of said traction straps (16) to thereby maintain contact between the traction straps and the mesh. A heat transfer system according to claim 1 or claim 2, wherein the load applying means comprises a flexible surface consisting of individual pivoted or spring-loaded shoes, the overall effect of which is to maintain uniform contact between the mesh and the hot surface.