| 摘要 |
A method of isolating a hydrant having a riser pipe 1 connected to a head 3, an outlet pipe 11 extending from the head, and a jumper 8 comprising a bonnet 5 and plug 7 which seals the outlet from said riser. The method comprises: attaching to the outlet a closure device comprising a cap 12 and sealing means 14, to securely close the outlet pipe; opening the jumper so that water may flow from the supply via the riser into the head; positioning the sealing means within the riser and activating the sealing means e.g. a bagging off inflatable bladder such that it extends across the riser pipe to close the supply to the hydrant head. The bonnet and plug may be removed for refurbishment or replaced with a deployment head 15 for introduction of e.g. a camera or hydrophone 16 to the main and the sealing means removed. |
