Method for applying a slurry coating onto a surface of an inner diameter of a conduit

• US 10,520,265 B2
• Filed: 10/15/2015
• Issued: 12/31/2019
• Est. Priority Date: 10/15/2015
• Status: Active Grant

• Current Assignee: Praxair Technology Incorporated (Linde Plc)
• Original Assignee: Praxair Technology Incorporated (Linde Plc)
• Inventors: Kwark, Sang Muk, Lu, Zigui, Potempa, David P., Shelat, Maulik R.
• Primary Examiner(s): Fletcher, III, William P
• Application Number:
  US14/884,171
• Publication Number:
  US 20170108296A1
• Time in Patent Office: 1,538 Days
• Field of Search: 427233, 427236, 4273722, 427425, 4274722, 4274723, 427231, 118688, 118300, 118318, 118321, 118323, 165133, 165177
• CPC Class Codes: B05C 7/02 the liquid or other fluent material being projected
• CPC Class Codes: B05D 1/002 the substrate being rotated
• CPC Class Codes: B05D 1/02 performed by spraying
• CPC Class Codes: B05D 1/40 Distributing applied liquids or other fluent materials by members moving relatively to surface
• CPC Class Codes: B05D 2254/04 Applying the material on the interior of the tube
• CPC Class Codes: B05D 2401/10 Organic solvent B05D2401/21 takes precedence
• CPC Class Codes: B05D 2401/20 Aqueous dispersion or solution
• CPC Class Codes: B05D 2401/21 Mixture of organic solvent and water
• CPC Class Codes: B05D 2401/40 where the carrier is not clearly specified
• CPC Class Codes: B05D 3/065 After-treatment
• CPC Class Codes: B05D 3/066 involving also the use of a gas
• CPC Class Codes: B05D 7/22 to internal surfaces, e.g. of tubes
• CPC Class Codes: B05D 7/222 of pipes
• CPC Class Codes: B22F 3/22 for producing castings from a slip
• CPC Class Codes: B22F 5/00 Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product
• CPC Class Codes: C09K 5/14 Solid materials, e.g. powdery or granular
• CPC Class Codes: F28F 1/10 Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses crimped or corrugated elements F28F1/06, F28F1/08
• CPC Class Codes: F28F 13/185 Heat-exchange surfaces provided with microstructures or with porous coatings
• CPC Class Codes: F28F 13/187 especially adapted for evaporator surfaces or condenser surfaces, e.g. with nucleation sites

Abstract

A method for creating a coating onto an inner diameter of conduit, whereby an injection nozzle is moved in a forward direction until its tip is aligned with the end of the conduit. Slurry is pumped from a reservoir into the injection nozzle and then is discharged through the tip of the injection nozzle. The slurry flows, distributes and spreads onto the surface of the conduit. The conduit is rotated and the nozzle is retracted as slurry continues to discharge from the nozzle to coat the remainder of the conduit.

Claims

1. A method for applying a coating onto a surface of an inner diameter of a heat exchanger conduit, comprising:

feeding a pre-mixed slurry formulation into a slurry reservoir, said slurry reservoir operably connected to an injection nozzle;

introducing the injection nozzle in a forward direction into the heat exchanger conduit, said heat exchanger conduit defined, at least in part, by a longitudinal length extending between a first end and a second end;

configuring the injection nozzle to a first position within the heat exchanger conduit, said first position defined as a first end of the injection nozzle being substantially aligned with the first end of the heat exchanger conduit;

pumping said pre-mixed slurry formulation from said slurry reservoir and through said injection nozzle so as to discharge said pre-mixed slurry formulation from the first end of the injection nozzle towards the inner surface of the heat exchanger conduit;

detecting the discharged pre-mixed slurry formulation and, in response thereto;

rotating said heat exchanger conduit, thereby allowing the discharged pre-mixed slurry formulation to be spread and distributed substantially uniformly along the inner surface of the heat exchanger conduit; and

retracting at a predetermined feed rate said injection nozzle, said retracting occurring in a reverse direction opposite to said forward direction.

2. The method of claim 1, further comprising:

retracting the injection nozzle to a second position relative to the heat exchanger conduit, said second position defined as the first end of the injection nozzle being substantially aligned with the second end of the heat exchanger conduit.

3. The method of claim 2, further comprising:

deactivating the step of pumping said pre-mixed slurry formulation;

introducing air through the heat exchanger conduit;

heating said heat exchanger conduit; and

evaporating solvent from the coating applied onto the inner surface of the heat exchanger conduit.

4. The method of claim 3, wherein said air is introduced at about 10-50 standard cubic feet per hour (SCFH).

5. The method of claim 1, wherein said rotating occurs from about 100 to about 400 rpm.

6. The method of claim 1, wherein said first position is further defined as having a second end of the injection nozzle being substantially aligned with the second end of the heat exchanger conduit.

7. The method of claim 1, wherein said predetermined feed rate is about 0.6 to about 0.9 inches/sec of nozzle movement in the reverse direction.

8. The method of claim 1, further comprising pumping said pre-mixed slurry formulation at a rate of about 47-67 mL/min.

9. The method of claim 1, wherein said heat exchanger conduit is a tube having an inner diameter of about 1 inch or less.

10. The method of claim 1, wherein said predetermined feed rate is about 0.6 to about 0.9 inches/sec of nozzle movement in the reverse direction, said pre-mixed slurry formulation is pumped at a rate of about 47 to about 67 mL/min, and said predetermined feed rate is at about 0.6 to about 0.9 inches/sec of nozzle movement in the reverse direction.

11. The method of claim 1, wherein said steps of retracting and rotating occur simultaneously.

12. The method of claim 1, wherein said injection nozzle is substantially coaxially aligned with the heat exchanger conduit.

13. The method of claim 1, further comprising sintering the coating.

14. The method of claim 1, wherein said pre-mixed slurry formulation is discharged so as to create a coating thickness of from about 12 to about 16 mils.

15. A method for applying a coating onto a surface of an inner diameter of a heat exchanger conduit, comprising:

feeding a pre-mixed slurry formulation into a slurry reservoir;

introducing an injection nozzle in a forward direction into the heat exchanger conduit;

configuring the injection nozzle to a first position within the heat exchanger conduit;

pumping said pre-mixed slurry formulation from said slurry reservoir and through said injection nozzle so as to discharge said pre-mixed slurry formulation towards the inner surface of the heat exchanger conduit;

detecting the discharged pre-mixed slurry formulation and, in response thereto;

rotating said heat exchanger conduit, thereby allowing the discharged pre-mixed slurry formulation to be spread and distributed substantially uniformly along the inner surface of the heat exchanger conduit; and

retracting at a predetermined feed rate said injection nozzle while rotating said heat exchanger conduit, said retracting occurring in a reverse direction opposite to said forward direction.

16. The method of claim 15, wherein said heat exchanger conduit and said nozzle have substantially the same longitudinal length.

17. The method of claim 15, wherein about 60 to about 84 g of coating is applied onto the surface of the inner diameter so as to attain a maximum thickness variation along the heat exchanger conduit of no greater than about 2.0 mils.