Method for coating an interior surface of a pipe

1. A method of coating an interior surface of a pipe, comprising:

spraying, with a robotic multi jet system present inside the pipe, a composition comprising a photocatalyst onto the interior surface of the pipe to form a sprayed interior surface, then

drying, with the robotic multi-jet system present inside the pipe, the sprayed interior surface to form a coated interior surface;

wherein the robotic multi jet system comprises:

a robot having a spray section, a drier section, and a catalyst section;

wherein the drier section comprises a warm air blower;

the catalyst section comprises a photocatalyst tank, and

the spray section comprises a plurality of jet extensions, wherein each jet extension terminates in one or more jets;

wherein the photocatalyst tank contains a submersible pump; and

wherein a first jet extension is fluidly connected to the photocatalyst tank through the submersible pump and is configured to spray a uniform layer of a photocatalyst contained in the photocatalyst tank through a first set of jets, and a second jet extension is mechanically connected to the drier section in fluid communication with the blower and is configured to blow a gas onto the interior surface of the pipe through a second set of jets;

wherein the first and second jet extensions are made of stainless steel;

wherein the drier section and the catalyst section are separate sections that are connected by a metal bend chain link;

wherein both the drier section and the catalyst section are separately mounted on wheels configured to support and move the robotic multi jet system on the interior surface of the pipe;

wherein the spray section, the drier section, and the catalyst section are laterally connected with the drier section at a first end, the spray section at a second end and the catalyst section in between the first and second ends;

wherein the first set of jets are located at a terminal end of the second end;

wherein the second set of jets are located in between the first set of jets and the catalyst section; and

a motor that is electrically connected to a battery mounted within the robot, wherein the motor is pivotally mounted to the wheels and configured to move the robotic multi jet system on the wheels across the interior surface of the pipe.

2. The method of claim 1 , wherein each jet extension of the plurality of jet extensions of the robotic multi jet system comprises at least 4 jets.

3. The method of claim 1 , wherein the first set of jets of the robotic multi jet system comprises at least 2 jets.

4. The method of claim 1 , wherein the second set of jets of the robotic multi jet system comprises at least 2 jets.

5. The method of claim 1 , wherein the submersible pump of the robotic multi jet system is completely disposed within the photocatalyst tank to supply the photocatalyst to the first set of jets.

6. The method of claim 1 , wherein each jet of the plurality of jets of the robotic multi jet system is in a shape of a disc.

7. The method of claim 1 , wherein individual jets of the first set of jets of the robotic multi jet system are connected in parallel with neighboring jets.

8. The method of claim 1 , wherein individual jets of the second set of jets of the robotic multi jet system are connected in parallel with neighboring jets.

9. The method of claim 1 , wherein the individual jets of the first and second set of the robotic multi-jet system are configured to oscillate 180°during spraying.

10. The method of claim 1 , wherein the pipe is a cylindrical glass tube.

11. The method of claim 1 , wherein the uniform layer has a thickness of from 10 nm to 5 μm.

12. The method of claim 1 , wherein the blower is electrically connected to the battery and comprises a plurality of resistive heating elements electrically connected to the battery such that the blower blows warm air.

13. The method of claim 12 , wherein the blower is disposed perpendicular to the battery within the drier section.