VALLEY GUTTER DEVICE FOR GREENHOUSE, VALLEY GUTTER MATERIAL, AND METHOD OF STRETCHING PLASTIC FILM

摘要

A method of stretching plastic film capable of increasing the workability of a stretching operation for plastic film installed at the valley part of a multi-span greenhouse, comprising the steps of disposing a part of spacer members (30) on a valley bottom part (110), placing a valley gutter material (20) on the upper part of the spacer members (30), fixing the valley side end parts of the plastic films covering valley inclined parts (120, 130) by applying some tension to the film engagement parts (24, 25) of the valley gutter material (20) by using spring members and film fixtures, removing the spacer members (30), and tighten a screw member (40), whereby the bottom wall part (21) of the valley gutter material (20) positioned apart from the valley bottom part (110) by an amount of the thickness of the spacer member (30) approaches the valley bottom part (110) to fit onto a girder (111) forming the valley bottom part (110), and since the positions of the film engagement parts (24, 25) provided on inclined wall parts (22, 23) are moved, the valley side end parts of the plastic films are moved in a direction apart from ceiling side end parts to increase the tension of the plastic films.