Abstract: A solar collector includes a transparent envelope and an absorber panel extending therethrough, the transparent envelope being constituted of a transparent plastic tube of smaller diameter than the width of the absorber panel such that the absorber panel supports the transparent plastic tube in an oval shape. In the described method of making the solar collector, a transparent plastic sheet is first bent into a right circular cylinder with its longitudinal edges secured together; and then a rigid absorber panel, having a width greater than the diameter of the cylinder, is inserted into the cylinder to deform it into an oval shape.

Abstract: A quickly-attachable pipe coupling comprises a flexible tube having an internal diameter approximately equal to the outer diameter of the pipe to be coupled, and a cylindrical spring overlying the flexible tube. The cylindrical spring includes a closely-wound coil of flat spring material having more than one turn, and having an inner diameter in its relaxed condition less than the outer diameter of the flexible tube. The coil spring is partially uncoilable under stress to open by increasing its inner diameter at least to the outer diameter of the flexible tube. Thus, the flexible tube and the cylindrical spring thereover, when in its stressed open condition, may be applied over the end of the pipe to be coupled, whereupon the cylindrical spring may be relaxed to close and to cause it to compress the flexible tube into tight engagement with the pipe for the complete length of the coil spring.