The invention discloses a
snow-proof external sun-shading
system applied to a Venlo type multi-span glass
greenhouse. An
aluminum foil bubble curtain with a sun-shading rate of 70 percent is adopted, and moves along the direction of a
ridge. Double-layer plastic-coated [PE / PET / PA (
polyethylene /
polyethylene terephthalate /
polyamide)] steel wire ropes with supporting and windproof functions are adopted, and are fixedly arranged on a
metal structural net rack on the roof of the
greenhouse at transverse intervals of 30 to 100cm which are determined by the material of the curtain. The
metal structural net rack is fixedly arranged on roof gutters, and is higher than roof glass. The
aluminum foil bubble curtain for sun shading is driven to move by a pulling roller. The
aluminum foil bubble curtain can be reeled under the transmission of the pulling roller according to the magnitude of snowfall on snowy days,
snow on the curtain can be transmitted to the ground on the outer side of the
greenhouse at a certain time interval, the
snow bearing time of the curtain can be set in advance, and the curtain returns to the roof to continue bearing the snow, so that pressure of snow loads on the roof of the greenhouse is greatly reduced (by over 80 percent). The external sun-shading
system has the functions of regulating the
illuminance, reducing the temperature, preserving heat and reducing the influence of natural disasters such as hailstones and blizzards; the accumulated snow on the roof can be removed in a timing way, so that a lightweight material can be selected for the steel structural design of the greenhouse, and the construction cost is lowered.