Fluid control valve

A fluid control valve comprising:

• a valve body defining an outer wall for a curved flow path through the fluid control valve, the outer wall defining a throat point;
• a valve element, rotatable relative to the valve body about a pivot point, through a rotatable travel, between a closed position in which the flow path is closed, and a range of open positions in which an outlet is defined between the valve element and valve body;
• wherein the valve element defines a first inner wall configured to oppose a downstream portion of the outer wall when in the range of open positions to define a restrictor portion of the flow path, a second inner wall configured to oppose an upstream portion of the outer wall when in the range of open positions, and a closure point where the first inner wall meets the second inner wall configured to engage the throat point on the outer wall when the in the closed position;
• wherein a separation between the first inner wall and the outer wall along the restrictor portion of the flow path varies through the range of open positions;
• wherein the separation is defined as the distance between the first inner wall and the outer wall for each open position included in the range of open positions,
• wherein the restrictor portion of the flow path is defined between the throat point on the outer wall and the closure point on the first inner wall for each open position included in the range of the open positions;
• and
• wherein the first inner wall and the outer wall are cooperatively defined so that, for at least some open positions included in the range of open positions, the separation between the first inner wall and the outer wall is constant along the restrictor portion of the flow path.