Outer wall-heated two-phase flow detector

(canceled)

3:

• The apparatus of claim 1, wherein the hollow tube is at least 1 inch in inner diameter.

4:

• The apparatus in claim 1, wherein the hollow tube is secured to the pipe by a threaded coupling fitting.

5:

• The apparatus in claim 1, wherein at least a portion of the hollow tube is covered by a thermal insulation material.

6:

• The apparatus in claim 1, wherein the wiring of the thermocouple is aligned with the longitudinal axis of the hollow tube and flush with the interior wall of the hollow tube.

7:

• The apparatus in claim 1, wherein the wiring of the thermocouple is insulated.

8:

• The apparatus of claim 1, further comprising an external thermocouple located outside of the hollow tube and within the interior of the pipe, which measures the external temperature of the tube.

9:

• The apparatus of claim 1, which has at least 4 thermocouples.

10:

• The apparatus of claim 1, wherein the heat flux source produces at least 0.5 kW of power.

11:

• The apparatus in claim 1, further comprising an electronics housing unit comprising the potentiometer connected to the thermocouples and a heat flux controller connected to the heat flux source.

12:

• The apparatus in claim 11, further comprising:
• a computer connected to the potentiometer and the heat flux controller.

13:

• The apparatus of claim 1, wherein the two-phase liquid-gas mixture is selected from a hydrocarbon, a heat transfer fluid, an aqueous fluid, or a combination thereof.

14-17. (canceled)