| 主权项 |
1. Shutter with automatically expanding sealing ring adapted to close a duct and mobile along a vertical axis and substantially perpendicular to the longitudinal axis of the duct, comprising:
at least one abutment block adapted to support the pressure inside; and at least one head adapted to make a seal to a pressure inside duct, said head assuming a rest position outside the duct wherein it is coaxial with the abutment block along a vertical axis, and an operating sealing position inside the duct along a longitudinal axis of the duct; wherein the head makes the pressure seal through a compression of a sealing ring with trapezoidal section compressed by a mobile flange against a fixed flange the head being equipped with mobile sectors which automatically go out during their insertion operation in order to contain and protect the sealing ring, wherein, starting from a rest position in which the head is aligned with the abutment block along the vertical axis, to get to its sealing position in the duct, when a chute placed at the lower end of the head touches the bottom of the duct, the head is adapted to start rotating till it gets coaxial with the duct and substantially at 90° with respect to the abutment block, in such position, the small interchangeable block fastened to the abutment block being resting on the bottom of the duct, the sectors going out of their seat due to the contact of wheels onto the convex surface of the abutment block, such wheels being adapted to push, through an axle, an assembly composed of two cylinders between which a pack of belleville washers is interposed, the assembly pushing in turn a frustum-of-cone which, through its lateral surface, transfers the compressing force to the mobile sectors which thereby go out, if the internal diameter of the duct is smaller than the diameter of the circumference intercepted by the sectors in a maximum expansion position, the compressing force being discharged onto the pack of belleville washers, compressing them. |
