Variable orifice rotary valve for controlling gas flow

A variable orifice rotary valve for controlling gas flow, comprising:

• a housing of the valve including a substantially cylindrical interior passage, and a housing opening extending from the interior passage through the housing;
• a rotatable valve element comprising a sidewall having a cylindrical external sidewall surface and an internal wall surface, the valve element having a main opening;
• at least one slot in the sidewall, the at least one slot varying in depth along a circumferential length of the at least one slot and terminating in an opening in the sidewall,
• the valve element rotatably received within the interior passage of the housing such that a rotation of the valve element within the interior passage determines a circumferential length and a depth of a portion of the slot that overlaps with the housing opening.

A method of operating a medical ventilator having a valve in which a valve element comprising slots rotates within a housing, the method comprising:

• rotating the valve element such that a first slot is configured to provide a range of gas flow rates suitable for neonates without making use of the second slot and such that as the valve element is rotated the depth of the first slot, aligned with a housing opening, varies;
• and
• further rotating the valve element such that a wider second slot is configured to provide a range of gas flow rates suitable for adult without making use of the first slot,
• wherein the first slot and the second slot are circumferentially spaced from one another.