Reagent tank normalizing system

1. A reagent injection system for reducing emissions from an engine, the system comprising:

a reagent container;

a heating element positioned in a heat transfer relationship with reagent stored within the container; and

an interchange tube having a first end in receipt of a recirculated liquid reagent and a second open end positioned in the container, the interchange tube including a bleed-off tube branching off of the interchange tube between the first and second ends, wherein a terminal end of the bleed-off tube is positioned within a vapor dome above a surface of the reagent.

2. The system of claim 1 , wherein the interchange tube includes a plurality of transversely extending apertures.

3. The system of claim 2 , wherein the second end of the interchange tube is proximate the heating element.

4. The system of claim 3 , wherein the terminal end of the bleed-off tube is positioned to direct a stream of recirculated liquid reagent toward a frozen portion of reagent.

5. The system of claim 4 , wherein the interchange tube provides a plurality of passageways through the container to equalize the pressure between spaced apart zones in the container.

6. The system of claim 1 , wherein the heating element is positioned proximate the bottom of the container.

7. The system of claim 1 , further including a pump drawing liquid reagent through a supply line in fluid communication with the container.

8. The system of claim 7 , further including a return line supplying the pumped and recirculated reagent that has not been injected into the engine exhaust to the first end of the interchange tube.

9. The system of claim 8 , further including an injector positioned at the junction of the supply line and the return line, the injector injecting reagent into the engine exhaust.

10. The system of claim 7 , wherein the supply line includes an inlet positioned proximate a bottom of the container.

11. The system of claim 10 , wherein the heating element is positioned within the container between the second end of the interchange tube and the inlet.

12. A reagent injection system for reducing emissions from an engine, the system comprising:

an injector;

a reagent container;

a pump for pumping liquid reagent from the container;

a supply line connecting the pump and the injector;

a return line for recirculating reagent from the injector to the container;

a heating element positioned in a heat transfer relationship with reagent stored within the container; and

an interchange tube having a first end in communication with the return line for receipt of the recirculated liquid reagent and a second open end positioned in the container, the interchange tube including a bleed-off tube branching off of the interchange tube between the first and second ends, wherein a terminal end of the bleed-off tube is positioned within a vapor dome above a surface of the reagent.

13. The system of claim 12 , wherein the interchange tube includes a plurality of axially spaced apart and transversely extending apertures.

14. The system of claim 12 , wherein the second end of the interchange tube is proximate the heating element.

15. The system of claim 12 , wherein the terminal end of the bleed-off tube is positioned to direct a stream of recirculated liquid reagent toward an outer surface of the interchange tube.

16. The system of claim 12 , wherein the interchange tube provides a plurality of passageways through the container to equalize the pressure between spaced apart zones in the container.

17. The system of claim 12 , wherein the supply line includes an inlet positioned proximate a bottom of the container.

18. The system of claim 17 , wherein the heating element is positioned within the container between the second end of the interchange tube and the inlet.