DEVICE TO OVERLAP AN APERTURE OF AN EXHAUST SHAFT Russian patent published in 1995 - IPC

FIELD: fire-fighting equipment. SUBSTANCE: device has body 1 with aperture 2, plates 3 to overlap aperture 2. The plates are installed to enable revolving around axle 4, and their bent ends form labyrinth seal. The outer upper plate is linked to electromagnet 5 by drive tie rod in the form of rack 7 and pinion 8 as a gear pair. The outer lower plate is linked to additional electromagnet 6 by similar drive tie rod. Plates 3 are connected to each other by pinions 11. EFFECT: wider operating opportunities. 3 dwg