Patent ID: 6971398

Claim:
A flow controller for releasably blocking a flow of liquid in a flow path defined by a closed perimeter, the flow controller comprising: a rigid self-supporting panel configured to overlap the closed perimeter, the panel being provided with a first hinge member configured to mount the panel in a normal orientation overlapping the closed perimeter to substantially block the flow path, the first hinge member being further configured to allow the panel to move from the normal orientation to release the flow of the liquid, the panel being further configured with a torque member to define an amount of a normal process force of the flow of the liquid to be substantially blocked by the panel and an amount of a hydrodynamic force of the flow of the liquid to be released by the panel, the panel being further configured with a series of offsets to define channels configured to resist the amount of the normal process force of the flow of the liquid to be substantially blocked by the panel, the channels comprising a top channel section; the first hinge member being configured in the top channel section; and the torque member being configured with a weight having a selected value which when acting around the first hinge member defines the amount of the normal process force of the flow of the liquid to be substantially blocked by the panel and the amount of the hydrodynamic force of the flow of the liquid to be released by the panel.