Patent ID: 8186648
Filing Date: 2012-05-29
Classification: F16L,Y10T

Abstract:
1. A method of shutting off a conduit in a fluid piping system, the method comprising the steps of attaching a shutoff operation cover to two pipe portions fastened and joined together with a fastener, said shutoff operation cover being capable of sealingly surrounding outer peripheries of respective joining flange portions of the two pipe portions, with allowing a loosening operation of the fastener, said shutoff operation cover including a gate plate valve capable of shutting off conduits of the two pipe portions, the gate plate valve being provided in the form of a thin plate and insertable and withdrawable; and inserting the gate plate valve of the shutoff operation cover from a conduit opening position to a conduit shutting position through a gap formed between the two joining flange portions in association with the loosening operation of the fastener, thereby shutting off the conduit between the two joining flange portions; wherein when an attaching operation of the shutoff operation cover to the two pipe portions is to be started, a leading end portion of the gate plate valve protrudes within an annular gap formed on an outer peripheral side, which is a conduit shutting position side, of opposing faces of the two joining flange portions, and according as the leading end portion comes into contact with a portion of the pipe portion in the course of its movement into the annular gap during the attaching operation of the shutoff operation cover, the leading end portion of the gate plate valve is retracted toward a conduit opening position side, and when the shutoff operation cover is attached to the two pipe portions, the leading end portion of the gate plate valve at its conduit opening position is positioned into the annular gap relative to a contacting portion of the shutoff operation cover coming into contact with the outer peripheries of the two joining flange portions.