Methods for making pre-fabricated insulated wall structures and apparatus for use in such methods

A method of making a pre-fabricated insulated wall structure comprising:

• (a) attaching a 1 to 2 inch thick foam panel to a front frame surface of a substantially horizontally positioned frame, wherein
• (i) the frame comprises a first member, a second member spaced apart from the first member;
• and connecting members extending between the first member and the second member, wherein the first member, the second member, and the connecting members are 2×4 or 2×6 members,
• (ii) the first member, the second member, and the connecting members each comprise a front surface and a rear surface that form the front frame surface and a rear frame surface, and
• (iii) the foam panel, the first members, the second member, and the connecting members define a cavity within the frame;
• (b) placing the frame having the foam panel attached thereto on a track conveyor configured to convey the frame in a substantially upright position in which the frame lies on rotating members of a substantially vertically positioned track and the foam panel lies on rotating members of a substantially horizontally positioned track;
• (c) conveying the frame having the foam panel attached thereto on the track conveyer in a substantially upright position to a spray foam application station;
• and
• (d) spray applying a spray foam composition into the cavity of the substantially upright positioned frame having the foam panel attached thereto in the spray foam application station to form a substantially upright positioned pre-fabricated insulated wall structure having a foam layer deposited in the cavity in which the foam layer adheres to the foam panel,
• wherein the track conveyor is configured so that, during the conveying, only the frame rests on the rotating members of the substantially vertically positioned track in cases where the foam panel covers the entire front frame surface.