Valve with shuttle for use in a flow management system

1. A valve for use in a flow management system comprising:

a valve body with a spill port;

a shuttle located in a chamber of the valve body;

the shuttle having a through hole extending between a shuttle closure end and a shuttle spring end;

a valve center line shared by the valve body and the shuttle;

a first seat located on a first face of the shuttle; a first seat closure;

the first seat closure having a central bore for accepting a rotatable shaft extending through the valve body;

the first seat closure for translating along the rotatable shaft;

a second seat located in the valve body chamber and a second seat closure located on a second face of the shuttle;

a spring located substantially between the shuttle spring end and a valve body support; and,

the valve operable to pass a flow entering the through hole at the shuttle spring end and to spill a flow that closes the first seat closure.

2. The valve of claim 1 wherein the first seat is about radially oriented with respect to the valve center line.

3. The valve of claim 2 wherein the second seat is about radially oriented with respect to the valve center line.

4. The valve of claim 3 wherein the second seat is formed on an inwardly projecting surface of the valve body.

5. The valve of claim 4 wherein a spill port is bounded by the first closure, the shuttle closure end and the valve body when the spill port is open.

6. The valve of claim 5 wherein the spring tends to close the spill port.

7. The valve of claim 6 wherein the difference between the radii of the first and second seats is limited by a shuttle wall thickness.

8. The valve of claim 7 wherein rotation of the shaft operates a pump causing flow through the valve to lift the first closure free of the shuttle.

9. A method of protecting a pump comprising the steps of:

providing a fluid to be lifted and a pump for lifting the fluid;

providing a valve downstream of the pump, the valve including

a valve body with a spill port;

a shuttle located in a chamber of the valve body;

the shuttle having a through hole extending between a shuttle closure end and a shuttle spring end;

a valve center line shared by the valve body and the shuttle;

a first seat located on a first face of the shuttle; a first seat closure;

the first seat closure having a central bore for accepting a rotatable shaft extending through the valve body;

the first seat closure for translating along the rotatable shaft;

a second seat located in the valve body chamber and a second seat closure located on a second face of the shuttle;

a spring located substantially between the shuttle spring end and a valve body support and,

passing a flow entering the through hole at the shuttle spring end; and,

spilling a flow that closes the first seat closure.