In the prior art, it is known to produce rigid foam products with or without various reinforcing materials or sheathing for use in building construction. These types of rigid foam products are desirable for their high structural strength, low density and superior insulating properties. In one method and apparatus for making these types of foam products, a partially expanded froth of foamable chemicals is continually applied to a moving substrate. Once applied to the moving substrate, the froth completely expands under controlled conditions including dimensional restraint, temperature, moving substrate speed, etc., to form the foam product. The foam product may also include a facing sheet attached to one or both surfaces depending on the intended use. The thus-formed foam product can then be cut to specified lengths.
FIG. 1 shows a prior art rigid foam laminating line. The laminating line includes material tanks 1 with agitators 3. The material tanks contain the foaming chemicals which are subsequently mixed as described hereinafter. Metering pumps 5 pump the foaming materials through the heat exchangers 7 to the mixing head 9. Adjacent the mixing head is a traversing assembly 11 which spreads the mixed foaming materials across the bottom facer 13. The bottom facer is fed from the bottom facer role 15 and alignment device 17.
Likewise, a top facer role 19 and alignment device 21 feed a top facer into the nip rolls 23. The facer materials and foaming materials proceed through the curing oven 25 disposed between an upper conveyor 27 which is adjustable in height and a lower conveyor 29. The foam product 31 expands between the upper and lower conveyors forming a rigid product 33. The rigid product 33 is side trimmed via the side-trim saws 35 and cut to length via the cut-off saw 37. The stacked foam panels 39 are then ready for packaging and use.
The upper and lower conveyors 27 and 29 can be any endless types, including a series of articulated platens supported and run over a roller assembly or chain. An endless conveyor of this type is disclosed in U.S. Pat. No. 4,043,719, the disclosure of which being incorporated herein by reference.
A similar method and apparatus is disclosed in U.S. Pat. No. 4,572,865 to Gluck et al. The teachings of this patent are also herein incorporated by reference in their entirety.
It is also known to produce foam products in different shapes and contours for construction use, in particular, roof insulation, by various processes. U.S. Pat. Nos. 5,069,950 to Crookston, Sr. and 4,712,349 to Riley et al both disclose a grooved foam panel for use in a roof insulating structure. However, the grooves are formed by cutting or laminating which contributes to increased product costs and lower manufacturing productivity due to the tedious nature of the groove formation process.
In U.S. Pat. No. 5,067,298 to Peterson, a grooved front panel is used in decking construction wherein the panel is extruded with the grooves therein.
Continuous formation of foam product methods and apparatus also impart different shapes to the foam product. In U.S. Pat. No. 4,087,501 to Moser, plastic foamed pipe sleeves are continuously formed using traveling molds. U.S. Pat. No. 3,553,300 to Buff discloses an apparatus and method for making continuously formed foamed product wherein a top pressure device is controlled to adjust the longitudinal contour of the foamed product.
However, the prior art methods and apparatus are disadvantageous in failing to teach or suggest an efficient, simple and low cost method or apparatus for forming grooves or venting channels in continuously-formed foamed product. Prior art methods of extruding, cutting or laminating are inefficient in cost, yield and productivity. As such, a need has developed to provide an improved apparatus, method and foamed product with venting channels therein as a building product which eliminates tedious or cost ineffective procedures for venting channel formation.
In response to this need, the present invention provides a method and apparatus for forming foam products with venting channels therein. The present invention permits the continuous formation of a plurality of venting channels in foamed product through the use of a forming plate in conjunction with upper and lower endless conveyors during product foaming.