Waterworks Technology Development Organization Co., Ltd.

Atsushi Sakai

Akihito Totsugi

To enable efficient and easy attachment of a shutoff operation cover at a proper attaching position relative to two joining flange portions and also to restrict deformation in a leading end portion of a gate plate valve. A shutoff operation cover B is attached to two pipe portionsjointed and fastened together with a fastener. The shutoff operation cover B is capable of surrounding outer peripheries of the two joining flange portionsA,A under a sealed condition, and there is provided a gate plate valvein the form of a thin plate, the valve being insertable and withdrawable for shutting off conduits of the two pipe portions. As the gate plate valveis inserted to a conduit shutting position through a gap S formed between the two joining flange portionsA,A in association with a loosening operation of the fastener, the conduit is shut off between the two joining flange portionsA,A. When the shutoff operation cover B is attached to the two pipe portions, a leading endof the gate plate valvelocated at a conduit opening position is advanced into an annular gapformed on the outer peripheral sides of opposing faces of the two joining flange portionsA,A.

Method of shutting off conduit and pipe conduit shutoff apparatus

A pipeline closing apparatus comprises a lid member attachable to a downstream end portion of a sluice valve, a first control shaft extending through the lid member, a second control shaft extending through the first control shaft, an elastic annular member disposed between pressing plates and provided on inward end regions of the control shafts and elastically deformable to a diameter-increased position by being clamped and pressed, thereby to block between an inner peripheral surface of a branch pipe and the pressing plates, and a retaining device. The retaining device includes engaging link pairs flexing and bulging to a diameter-increased position in response to outward sliding movement of the second control shaft relative to the first control shaft. The apparatus further comprises a reversal preventing device F which, contacts and limits the engaging link pairs and to an outwardly bent position where flexing pivotal portions of the engaging link pairs project radially outward.

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Sasayama, Japan

Atsushi Sakai