The roofs of membrane connected greenhouses are divided into circular arch and pointed roof types, and some are flat roof types. The water on the roof will flow to the sink area, so we only need to make a slope in the direction of the gutter. The slope in the sink direction is generally around 2.5 ‰, which is about 1cm in the direction of a 4-meter bay.
The film multi span greenhouse should have a slope. If there is no slope in the gutter of the film multi span greenhouse, it is easy for rainwater to flow back into the interior of the greenhouse during a heavy rainstorm. If there is no slope in the gutter of the film multi span greenhouse, it is easy to leave water in the sink during a light rain. If the water soaks the sink for too long, it will accelerate the rusting of the sink and affect the service life of the sink.
If the distance between the compartments of the greenhouse exceeds 40 meters, a bidirectional slope is generally adopted, which means that the sink is high in the middle and low on both sides, and water flows to both sides. If the distance between the compartments of the greenhouse is less than 40 meters, a unilateral drainage can be used, which means that one side of the sink is blocked and only the other side is drained. In addition, the distance in the gutter direction of the film multi span greenhouse is too long, and the drainage on both sides cannot meet the drainage index in rainstorm, so it is necessary to add an internal drain in the middle of the sink, that is, select the middle position, and open an opening at the bottom of the sink, so that the rainwater in the middle can flow into the greenhouse.
