| 主权项 |
1) A safety flow obstruction holder for connecting to a tank for storing a liquid, comprising:
a supply passageway for connecting to the tank; a ball valve for connecting to the supply passageway; a first drainage passageway for connecting to the ball valve; a second drainage passageway for connecting to the ball valve and being connected in parallel to the first drainage passageway; a connecting passageway to connect the first drainage passageway to the second drainage passageway; a first shut off valve to selectively shut off the first drainage passageway; and a second shutoff valve to selectively shut off the second drainage passageway. |
