Powder pipe coating booth

Patent metadata

Field	Value
Publication number	US-10226786-B2
Application number	US-201313967443-A
Country	US
Kind code	B2
Filing date	Aug 15, 2013
Priority date	Aug 15, 2013
Publication date	Mar 12, 2019
Grant date	Mar 12, 2019

Abstract

Apparatus for coating a heated pipe section with a fusible powder includes a booth enclosing a powder application volume, at least one powder dispensing device for dispensing powder supplied to the device in the direction of the heated pipe section as the heated pipe section passes through the volume, and a filter mechanism coupled to the booth for extracting from the booth a stream of air entraining fusible powder that does not stick to the heated pipe section and extracting the fusible powder that does not stick to the heated pipe section from the volume. The apparatus further includes an opening between the volume and the filter mechanism. The opening permits the mixing of cooler air into the stream of air entraining fusible powder that does not stick to the heated pipe section before the stream of air entraining fusible powder that does not stick to the heated pipe section reaches the filter mechanism.

First claim

What is claimed is:

1. Apparatus for coating a heated substrate in the form of a pipe with a fusible powder, the apparatus comprising:
a booth enclosing a powder application volume as part of a volume enclosed by the booth and smaller than the volume enclosed by the booth, the booth includes an inlet and an outlet for the pipe to pass longitudinally through the booth powder application volume between the inlet and the outlet;
at least one spray gun arranged in a single array only on a first side of the booth for dispensing powder supplied to the at least one spray gun in a direction substantially perpendicular to a passing direction of the heated substrate through the powder application volume from the inlet to the outlet,
a dust collector directly coupled to the booth at a first opening arranged in a second side of the booth opposite to the first side of the booth for extracting from the booth an overspray-laden airstream generated during the dispensing of the powder by means of the at least one spray gun, the overspray-laden airstream including a stream of air entraining at least a portion of fusible powder that does not stick to the heated substrate, and for extracting the portion of entrained fusible powder that does not stick to the heated substrate from the powder application volume, and
a second opening in the booth directly between the powder application volume and the dust collector, the second opening being sized and positioned to permit, during the dispensing of the powder by the at least one spray gun, the mixing of cooler room air from outside of the booth at essentially room temperature into the stream of air entraining fusible powder that does not stick to the heated substrate to lower the temperature of the portion of entrained fusible powder that does not stick to the heated substrate to a temperature below the fusion temperature of the fusible powder before the portion of entrained fusible powder reaches the dust collector;
wherein the dust collector comprises:
at least one fan adapted to pull the overspray-laden airstream from the booth through the first opening; and
a filter positioned adjacent to the first opening between the first opening and the at least one fan, the filter adapted to capture the portion of entrained fusible powder that enters the first opening such that the portion of entrained fusible powder is deposited on the outside of the filter;
wherein the dust collector is adapted to intermittently generate a pulse of air in a direction opposite the normal direction of airflow through the filter to dislodge the fusible powder from the outside of the filter such that the powder falls to the floor of the dust collector for recovery or recycling.

2. The apparatus of claim 1 , wherein at least one of the inlet and outlet is provided with sliding doors.

3. The apparatus of claim 1 , wherein at least one of the inlet and outlet is provided with a removable partition having an opening therethrough, the opening of a size corresponding to a diameter of the pipe so that the opening no larger than necessary to permit passage therethrough of the substrate to be coated.

4. The apparatus of claim 1 , wherein the at least one spray gun comprises a plurality of spray guns.

5. The apparatus of claim 1 further including an electrostatic power supply including a high magnitude terminal of the supply coupled to a charging electrode of the at least one spray gun and a low magnitude terminal coupled to the substrate as the substrate passes through the booth, electrostatically charged powder dispensed from the at least one spray gun forming a charged powder cloud surrounding the substrate, a charged powder coating from the powder cloud being attracted to the heated substrate.

6. The apparatus of claim 1 , wherein the second opening is adjustable to modulate the amount of cooler air at essentially room temperature for lowering the temperature of the fusible powder that does not stick to the heated substrate below the fusion temperature of the fusible powder that does not stick to the heated substrate.

Assignees

• Gema Switzerland Gmbh

Inventors

• Flasher Philip S

Classifications

• B05B13/0228

  the movement of the objects being rotative (B05B13/0242 takes precedence) · CPC title

• B05B14/43 Primary

  by filtering the air charged with excess material · CPC title

• B05B16/95

  the objects or other work to be sprayed lying on, or being held above the conveying means, i.e. not hanging from the conveying means · CPC title

• C21D9/08

  for tubular bodies or pipes · CPC title

• B05B5/081

  specially adapted for treating particulate materials · CPC title