Positive hub seal

A method of using a valve, the method comprising:

• rotating a valve disc of the valve, the valve comprising:
• a valve body defining a shaft bore and an interior cavity, an axis of the shaft bore defining a vertical axis;
• a valve shaft positioned within and configured to rotate within the interior cavity of the valve body;
• the valve disc coupled to the valve shaft;
• and
• a valve seat positioned within the valve body, the valve seat comprising an outer surface in contact with the valve body and an inner surface in contact with the valve disc, the inner surface of the valve seat defining a sealing ridge extending radially inward, the sealing ridge having an annular shape about the valve shaft, the sealing ridge concentric with the valve shaft;
• contacting the sealing ridge of the valve seat with an axial end of the valve disc, the axial end of the valve disc defined with respect to the vertical axis;
• and
• compressing the sealing ridge.