| 摘要 |
<p>PURPOSE: A backflow prevention device is provided to prevent an opening and closing member from being leaned to one side by supplying elasticity to the center of the opening and closing member. CONSTITUTION: A backflow prevention device(100) comprises a housing(110), an opening and closing member(120), and a coil spring(130). The inside the housing is empty. The opening and closing member is arranged inside the housing and is reciprocated. The coil spring is arranged inside the housing and elastically supports the center of the opening and closing member.</p> |
