IE83898B1 - Manufacturing a foam board - Google Patents

Description

“MANUFACTURING A FOAM BOARD” Introduction The invention relates to the manufacture of a rigid polymeric insulating foam board of the type comprising a lower substrate, an upper substrate and a foam layer between the substrates.

In manufacturing such panels, liquid foam reactants are laid down on a lower substrate, an upper substrate is applied over the foam reactants and the sandwich thus formed is treated in an oven. During the process, the liquid foam reactants expand by a factor of about forty times and cells are formed as the foam structure develops. The foam structure is generally uniform across the main body of the panel. However, at the side edges there is disconformity in foam structure. Thus, the side edges of panels are always trimmed resulting in substantial wastage. The trim can be shortened, but generally at the expense of uniform foam structure adjacent to the panel side edges.

This invention is directed towards providing a method and apparatus which will address these issues.

Statements of Invention According to the invention there is provided a method for manufacturing a rigid polymeric insulating foam board of the type comprising a lower substrate, an upper substrate and a foam layer between the substrates, the method comprising the steps of:— leading a lower substrate of a substantially self supporting material such as foil from a reel onto a conveyor bed; guiding side edges of the lower substrate progressively upwardly as the substrate is led along the conveyor bed to form upturned side lips; applying liquid foam reactants to the lower substrate, some of the liquid foam reactants impinging on the upturned side lips of the base substrate; leading an upper substrate over the foam reactants to form a panel sandwich; heating the panel sandwich in an oven; cutting away the side edges of the panel; and cutting the panel to a desired length.

In one embodiment of the invention the liquid foam reactants are applied to the base substrate through a spray bar extending longitudinally of the lower substrate and having a plurality of longitudinally spaced-apart outlet holes, the spray bar being slidably movable and the method comprising moving the spray bar to and fro across the lower substrate while applying a stream of liquid foam reactants across the lower substrate.

Preferably the guide means are adjustably mounted and the method comprises adjusting the position of the guide means to correspond with a desired foam board. The guide means may be adjustable to correspond to a lower substrate width.

In one embodiment the guide means comprises an outer guide member and an inner guide member between which the substrate is led to turn up the side edge of the substrate. Preferably the inner guide member is movable from an engaged position in which the lower substrate is led between the guide member to a release position.

The invention also provides an apparatus for manufacturing a rigid polymeric insulating foam board comprising a conveyor bed for receiving a lower substrate of a substantially self supporting material such as foil, guide means for guiding the side edges of the lower substrate progressively upwardly as the substrate is led along the conveyor bed to form upturned side lips, means for applying liquid foam reactants to the lower substrate, some of which impinge on the upturned side lips of the base substrate, means for leading an upper substrate over the foam reactants, and means for heating the board sandwich of upper and lower substrates with foam layer therebetvveen.

In a preferred embodiment the guide means is adjustably mounted for adjustment of the guide means to correspond with a desired width.

Preferably the guide means comprises an outer guide member and an inner guide member between which a side edge of a lower substrate is led to turn up the side edge and form a side lip. The inner guide member advantageously comprises a roller wheel.

In one embodiment the outer guide member comprises a plough with a leading edge against which the lower substrate is engaged and a progressively inwardly projecting face against which the lower substrate is raised.

Preferably the inner guide member is mounted for movement between a released inactive position and an engaged active position.

Brief Description of the Drawings The invention will be more clearly understood from the following description thereof given by way of example only, with reference to the accompanying drawings in which:- Fig. 1 is a plan view of apparatus used in a method for manufacturing a foam board according to the invention; Fig. 2 is a side cross-sectional View of the apparatus of Fig. l; Fig. 3 is a view of a detail of a foam laydown step in the method of the invention; Fig. 4 is a perspective view of a guide means used in the method and apparatus of the invention; Fig. 5 is an end view of the guide means, in use; Figs. 6(a) and 6(c) are cross-sectional views illustrating various steps in the method of the invention; and Fig. 7 is a cross-sectional View of a finished foam board.

Detailed Description Referring to the drawings there is illustrated in Fig. 7 a finished rigid polymeric insulating foam board l which is manufactured using the method and apparatus of the invention. The board 1 comprises a lower substrate 2, an upper substrate , and a foam layer 4 between the substrates 2, 3. In this case the lower substrate 2 is of a substantially self supporting material such as a foil which can be manipulated into a shape and which will generally retain the formed shape.

The lower substrate 2 is first led from a supply reel onto a conveyor bed 8 on a support frame 9. The lower substrate 2 has side edges 10, ll which are guided progressively upwardly by a guide means 15 on each side as the substrate 2 is led along the conveyor bed 8 to form upturned side lips l0a, lla. Liquid foam reactants are then applied to the lower substrate through a longitudinally arranged laterally movable spray bar 20. On application, some of the liquid foam reactants impinge against the inner faces of the upturned side lips lOa, lla to optimise the filling of the foam reactants in the region of the side lips l0a, lla.

The upper substrate 3 is led over the foam reactants to form a panel sandwich which is heated in a fixed gap oven. The foam reactants expand in the oven forming a continuous length of panel which is side trimmed by side edge cutting saws 25 and cut to desired length by a transversing saw.

Referring in particular to Figs. 4 and 5 each guide means 15 comprises an outer guide member 30 and an inner guide member 31 between which the lip lO(a) is formed. The outer guide member 30 comprises a plough with a leading edge 35 against which the side edge 10 of the substrate 2 is engaged. The plough 30 has a lip engaging face 36 against which the side edge 10 is progressively engaged as the substrate 2 moves along the conveyor 8 to form the raised side lip 10a. The plough 30 is adjustable in position to accommodate varying widths of lower substrate 2. The plough 30 is fixed to an arm 37 which is slidable over a rod 38 by turning a handle 40 of a screw 39 to move the plough 30 relative to the rod 38.

The inner guide member 31 comprises a roller which is rotatably mounted on a pin 41 fixed to a bracket 42. The bracket 42 is pivotally mounted about a pivot pin 43 for movement from an extended position illustrated by full lines in Fig. 5 in which the roller 31 is engaged against the substrate 2 to an inactive position swung away from the substrate 2 as illustrated by interrupted lines in Fig. 5 and by full lines in Fig. 4.

In use, the guides 15 are first set to a substrate width and, with the leading edge of the plough extending forwardly, the side edge 10 of the substrate 2 is turned up to form a lip 10a. The bracket 42 is then pivoted until the roller 31 is engaged against the substrate. In this arrangement the substrate lip l0(a) is formed between the plough 30 and the roller 31. As the conveyor 8 is driven the substrate side edges 10, ll are thereby continuously formed into the side lips l0a, lla on both sides. In this configuration the substrate 2 forms a tray (Fig. 6a) which is presented to the lay-down at which the spray bar 20 is traversed across the substrate 2. The spray bar 20 does not traverse completely up to the edges defined by the side lips l0a, lla but rather terminates a short distance from the side edge, the spray partially impinging against the side lips 10a, lla and liquid foam reactants flowing down to fill the side end regions. An upper substrate 3 is then led over the liquid foam reactants and the panel sandwich thus formed is led to a fixed gap oven (Fig. 6b). It will be noted, especially from Fig. 6b that the upper substrate 3 is narrower than the lower substrate 2 leaving a small gap through which excess foam can escape. After heating in an oven the side edges are trimmed (Fig. 6c) to form a continuous panel board which is cut to a desired length.

The formation of the side lips optimises the usage of foam reactants with minimum wastage and optimum foam cell consistency at the side edges of a board.

The invention is not limited to the embodiments hereinbefore described which may be varied in detail.

Claims (15)

1. A method for manufacturing a rigid polymeric insulating foam board of the type comprising a lower substrate, an upper substrate and a foam layer between the substrates, the method comprising the steps of:- leading a lower substrate of a substantially self supporting material such as foil from a reel onto a conveyor bed; guiding side edges of the lower substrate progressively upwardly as the substrate is led along the conveyor bed to form upturned side lips; applying liquid foam reactants to the lower substrate, some of the liquid foam reactants, an application impinging on the upturned side lips of the base substrate. leading an upper substrate over the foam reactants to form a panel sandwich; heating the panel sandwich in an oven; cutting away the side edges of the panel; and cutting the panel to a desired length.
2. A method as claimed in claim 1 wherein the liquid foam reactants are applied to the base substrate through a spray bar extending longitudinally of the lower substrate and having a plurality of longitudinally spaced- apart outlet holes, the spray bar being slidably movable and the method comprising moving the spray bar to and fro across the lower substrate 8 while applying a stream of liquid foam reactants across the lower substrate.
3. A method as claimed in claim 1 or 2 wherein the guide means are adjustably mounted and the method comprises adjusting the position of the guide means to correspond with a desired foam board.
4. A method as claimed in claim 3 wherein the guide means is adjustable to correspond to a lower substrate width.
5. A method as claimed in any preceding claim wherein the guide means comprises an outer guide member and an inner guide member between which the substrate is led to turn up the side edge of the substrate.
6. A method as claimed in claim 5 wherein the inner guide member is movable from an engaged position in which the lower substrate is led between the guide members to a release position.
7. A method for manufacturing a rigid polymeric insulating foam board substantially as hereinbefore described with reference to the accompanying drawings.
8. Apparatus for manufacturing a rigid polymeric insulating foam board comprising a conveyor bed for receiving a lower substrate of a substantially self-supporting material such as foil, and guide means for guiding the side edges of the lower substrate progressively upwardly as the substrate is led along the conveyor bed to form upturned side lips, means for applying liquid foam reactants to the lower substrate, some of which impinge on the upturned side lips of the base substrate; means for leading an upper substrate over the foam reactants; and means for heating the board sandwich of upper and lower substrates with foam layer therebetween.
9. Apparatus as claimed in claim 8 wherein the guide means is adjustably mounted for adjustment of the guide means to correspond with a desired width.
10. Apparatus as claimed in any preceding claim wherein the guide means comprises an outer guide member and an inner guide member between which a side edge of a lower substrate is led to turn up the side edge and form a side lip.
11. Apparatus as claimed in claim 10 wherein the inner guide member comprises a roller wheel.
12. Apparatus as claimed in claim 10 or ll wherein the outer guide member comprises a plough with a leading edge against which the lower substrate is engaged and a progressively inwardly projecting face against which the lower substrate is raised.
13. Apparatus as claimed in any of claims 10 to 12 wherein the inner guide member is mounted for movement between a released inactive position and an engaged active position.
14. Apparatus for manufacturing a rigid polymeric insulating foam board substantially as hereinbefore described with reference to the accompanying drawings. 10
15. 15. A rigid polymeric insulating foam board whenever manufactured by a method as claimed in any of claims 1 to 7 and/ or utilising an apparatus as claimed in any of claims 8 to 14.