Valve cartridge insensitive to installation load

1. A valve for controlling a flow rate of a fluid, the valve comprising:

an actuating mechanism including a ball portion and a projection extending from the ball portion;

a first fluid control disk including a recess operable to receive at least a portion of the projection;

a second fluid control disk; and

an annular spring having a central opening and a plurality of elastic flanges extending around a periphery of the central opening,

wherein an actuating force is operable to move the actuating mechanism,

wherein movement of the actuating mechanism moves the first fluid control disk relative to the second fluid control disk to vary the flow rate of the fluid,

wherein the annular spring is disposed between the actuating mechanism and the fluid control disks,

wherein the elastic flanges of the annular spring extend below an upper surface of the annular spring, away from the ball portion of the actuating mechanism and toward the fluid control disks,

wherein at least a portion of the ball portion including the projection extends through the central opening of the annular spring,

wherein the annular spring maintains contact with the actuating mechanism during movement of the actuating mechanism,

wherein the projection of the ball portion does not contact a lower surface of the recess of the first fluid control disk during movement of the actuating mechanism,

wherein the elastic flanges of the annular spring deform to exert a substantially uniform force on the ball portion of the actuating mechanism away from the fluid control disks,

wherein a first range of loading forces are operable to keep opposing surfaces of the first fluid control disk and the second fluid control disk in operative engagement,

wherein the first range of loading forces extends from a minimum loading force to a maximum loading force,

wherein a loading force less than the minimum loading force allows the fluid to leak from the valve,

wherein a loading force greater than the maximum loading force prevents movement of the first fluid control disk relative to the second fluid control disk,

wherein a threshold loading force is within the first range of loading forces,

wherein a second range of loading forces extends from the threshold loading force to the maximum loading force, and

wherein the actuating force remains substantially constant across a plurality of loading forces within the second range of loading forces.

2. The valve of claim 1 , wherein the range of loading forces corresponds to a range of torques of 25 to 200 lbs-in. applied to a retaining member for securing the valve in a valve body.

3. The valve of claim 2 , wherein the threshold loading force corresponds to a torque of 25 lbs-in. applied to the retaining member.

4. The valve of claim 2 , wherein the retaining member comprises:

a body for interfacing with the valve body, and

an annular flange formed on the body,

wherein the annular flange is operable to contact the valve body to limit a loading force applied to the valve by the retaining member.

5. The valve of claim 4 , wherein the retaining member is a nut.

6. The valve of claim 1 , further comprising a resilient member disposed between the actuating mechanism and the first fluid control disk,

wherein the resilient member exerts a preloading force on the actuating mechanism and away from the first fluid control disk.

7. The valve of claim 6 , wherein the resilient member is an annular spring.

8. The valve of claim 1 , wherein the first fluid control disk has a mixing chamber formed integrally therewith.

9. The valve of claim 1 , wherein the threshold loading force is closer to the minimum loading force than the maximum loading force.

10. The valve of claim 1 , wherein the threshold loading force is equal to the minimum loading force.