| 摘要 |
The lawn disclosed in the parent Specification is modified in that heating elements are disposed in the drainage openings. The elements may be embedded in the filler material in the openings and may be in the form of electrically heated wires. In a modification the heating elements are located in drainpipes laid adjacent to the bottom of the openings. In a further modification the heating elements comprise drainpipes, which preferably have openings in their shell, and which are adapted to be supplied with steam or warm air.ALSO:The lawn disclosed in the parent Specification is modified in that heating elements are disposed in the drainage openings. The elements may be embedded in the filler material in the openings and may be in the form of electrically heated wires. In a modification the heating elements are located in drainpipes laid adjacent to the bottom of the openings. In a further modification the heating elements comprise drainpipes which preferably have openings in their shell and which are adapted to be supplied with steam or warm air. |
