Flow control valve having a motion conversion device

A method for opening and closing a valve, comprising:

• providing a valve having a flow passage along an axial flow axis and a closure member;
• providing a housing positioned within the valve body and arranged to allow fluid to flow around the housing, the housing including defining a closed fluid circuit having a first bore in line with an external linear actuator, and a second bore, the first and second bores angled with respect to one another;
• providing a linear third bore to permit fluid communication between the first bore and the second bore, the third bore forming a portion of the closed fluid circuit and extending at an angle relative to the first and second bores
• positioning a first double-acting cylinder in the first bore;
• positioning a second double-acting cylinder positioned in the second bore;
• operatively connecting second double-acting cylinder to the closure member;
• moving the first double-acting cylinder under fluid pressure in one direction along a first axis to push the second double-acting cylinder in a first direction along a second axis, thereby moving the closure member in the first direction along the second axis to a closed position where the closure member prevents fluid flow through the flow passage;
• moving the first double-acting cylinder under fluid pressure in another direction along the first axis to push the second double-acting cylinder in a second direction opposite the first direction, thereby moving the closure member in the second direction along the second axis to an open position where the closure member permits fluid flow through the flow passage;
• and
• wherein the first and second double-acting cylinders include, respectively, first and second pistons possessing equal diameters such that a ratio of movement between the first piston along the first axis and the second piston along the second axis is 1:1.