Low spill high flow quick coupling valve assembly

A coupling valve assembly, comprising:

• a female coupling including a first movable piston, wherein in an uncoupled state, the first movable piston is sealed by a first seal having a first sealing diameter and a second seal having a second sealing diameter which is smaller than the first sealing diameter, an internal pressure exerts a force on a first annular area of the first movable piston which is defined between the first and second sealing diameters;
• a male coupling including a second movable piston, wherein in an uncoupled state, the second movable piston is sealed by a third seal having a third sealing diameter and a fourth seal having a fourth sealing diameter which is smaller than the third sealing diameter, an internal pressure exerts a force on a second annular area of the second movable piston which is defined between the third and fourth sealing diameters, and wherein the first sealing diameter is the same as the third sealing diameter, the second sealing diameter is the same as the fourth sealing diameter;
• and
• wherein when the female and male couplings are coupled in a coupled state, the first movable piston is sealed by the first seal and the third seal such that the first movable piston is pressure balanced under an internal fluid pressure, and the second movable piston is sealed by a fifth seal and the fourth seal such that the second movable piston is pressure balanced under the internal fluid pressure, the fifth seal has the same sealing diameter as the second seal.