Rotary disc valve

A rotary disc valve, comprising:

• a guide assembly comprising a ring-shaped member having a groove disposed in an inner surface thereof;
• a valve disc assembly rotatably coupled to the guide assembly, the valve disc assembly comprising:
• a valve disc,
• a projection received within the groove of the guide assembly;
• and
• a chimney support coupled to the guide assembly, the chimney support including a seal member for selectively sealing against the valve disc;
• wherein the groove has a main portion oriented perpendicular to a longitudinal axis of the rotary disc valve, and an angled portion oriented at an oblique angle with respect to the longitudinal axis;
• and
• wherein when the rotary disc valve is moved from a closed position toward an open position the valve disc assembly is rotated in a first direction with respect to the guide assembly, which moves the projection along the angled portion of the groove, thereby moving the valve disc away from the seal to decompress the seal;
• and
• wherein when the valve disc assembly is moved from the open position to the closed position the valve disc assembly is rotated in a second direction with respect to the guide assembly, which moves the projection along the angled portion of the groove, thereby moving the valve disc toward the seal to compress the seal.