Dense phase powder pump and corresponding operating method

Patent metadata

Field	Value
Publication number	US-10112787-B2
Application number	US-201414782298-A
Country	US
Kind code	B2
Filing date	Mar 18, 2014
Priority date	Apr 3, 2013
Publication date	Oct 30, 2018
Grant date	Oct 30, 2018

Abstract

The invention relates to a method and a dense phase powder pump ( 1 ) for conveying coating powder from a first powder reservoir ( 101 ) to a second downstream powder reservoir or to a downstream powder spray-coating gun ( 102 ) or the like installation for spraying coating powder. In order to reduce the number of components of the dense phase powder pump ( 1 ) that require maintenance, the dense phase powder pump ( 1 ) is designed as a single-chamber dense phase powder pump and has only a single powder conveyor chamber ( 4 ) for conveying coating powder.

First claim

The invention claimed is:

1. A dense phase powder pump for conveying coating powder in a powder path from a first powder reservoir to a second downstream powder reservoir or a downstream powder spray-coating gun or similar device for spraying coating powder disposed downstream of the dense phase powder pump, wherein the dense phase powder pump is designed as a single-chamber dense phase powder pump and comprises just one single powder conveyor chamber for the conveying of coating powder, wherein:
at least one auxiliary compressed air inlet device opens into at least one location in the powder path after a powder outlet valve of the dense phase powder pump to supply auxiliary compressed air as additional conveying compressed air as needed,
wherein the dense phase powder pump further comprises:
a powder inlet connected or connectable to the first powder reservoir; and
a powder outlet connected or connectable to the second reservoir or to the powder spray-coating gun or other such mechanism for spraying coating powder,

wherein the powder inlet is arranged at a first end region of the dense phase powder pump and the powder outlet at an oppositely situated second end region of the dense phase powder pump, and
wherein the single powder conveyor chamber is arranged between the powder inlet and powder outlet of the dense phase powder pump,
wherein the single powder conveyor chamber has a chamber powder inlet on a first end region and a chamber powder outlet on an oppositely situated second end region,
wherein the dense phase powder pump further comprises:
a powder inlet valve by means of which the chamber powder inlet of the single powder conveyor chamber can be fluidly connected or connectable to the powder inlet of the dense phase powder pump, and
a powder outlet valve by means of which the chamber powder outlet of the single powder conveyor chamber can be fluidly connected or connectable to powder outlet of the dense phase powder pump, and

wherein the powder outlet of the single powder conveyor chamber is or can be fluidly connected to the powder outlet of the dense phase powder pump by means of the powder outlet valve.

2. The dense phase powder pump according to claim 1 , wherein a control unit is further provided to actuate the powder inlet valve and/or powder outlet valve as well as alternatingly apply a negative pressure and an excess pressure in the single powder conveyor chamber.

3. The dense phase powder pump according to claim 2 ,
wherein the single powder conveyor chamber comprises at least one air exchange vent in order to alternatingly subject the single powder conveyor chamber to excess pressure or negative pressure; and
wherein the control unit is designed to alternatingly connect the air exchange vent of the single powder conveyor chamber to a vacuum line or vacuum source to suction coating powder into the single powder conveyor chamber through the open powder inlet valve while the powder outlet valve is closed, and to a compressed air supply line or compressed air source to pneumatically discharge a portion of powder from within the single powder conveyor chamber through the open powder outlet valve while the powder inlet valve is closed.

4. The dense phase powder pump according to claim 3 , wherein the at least one air exchange vent of the single powder conveyor chamber opens into the intermediate chamber, wherein the excess pressure and the negative pressure can be transmitted into the single powder conveyor chamber through the filter.

5. The dense phase powder pump according claim 1 , wherein the powder inlet valve and the powder outlet valve can be actuated separately from each other.

6. The dense phase powder pump according to claim 1 , wherein the powder inlet valve and the powder outlet valve are each designed as a pinch valve having a flexible elastic tube as a valve channel which can be squeezed by actuating compressed air in a pressure chamber surrounding the tube to close the respective valve.

7. The dense phase powder pump according to claim 6 , wherein application of a negative pressure in the pressure chamber of the respective valve causes opening of the powder inlet valve and/or powder outlet valve.

8. The dense phase powder pump according to claim 1 , wherein the single powder conveyor chamber comprises at least one air exchange vent in order to alternatingly subject the single powder conveyor chamber to excess pressure or negative pressure.

9. The dense phase powder pump according to claim 8 , wherein the dense phase powder pump comprises a compressed air/ vacuum source, and wherein the at least one air exchange vent of the single powder conveyor chamber is or can be connected to the compressed air/vacuum source.

10. The dense phase powder pump according to claim 9 ,
wherein the single powder conveyor chamber comprises at least one air exchange vent by means of which the single powder conveyor chamber can be intermittently subjected to conveying compressed air for discharging portions of powder out of the single powder conveyor chamber,
wherein the at least one auxiliary compressed air inlet device is designed such that the pneumatic resistance which occurs when auxiliary compressed air is fed into the powder path is substantially equal to the pneumatic resistance distributed when conveying compressed air is fed into the single powder conveyor chamber, and
wherein the at least one auxiliary compressed air inlet device comprises a chamber wall formed by a filter over at least part of its length which surrounds the powder path and separates the single powder conveyor chamber from an intermediate chamber surrounding the filter and formed between the filter and a housing, wherein the filter of the auxiliary compressed air inlet device is structurally identical to the filter of the single powder conveyor chamber.

11. The dense phase powder pump according to claim 1 ,
wherein the dense phase powder pump further comprises:
a powder inlet connected or connectable to the first powder reservoir;
a powder outlet connected or connectable to the second reservoir or to the powder spray-coating gun or other such mechanism for spraying coating powder;
a powder inlet valve by means of which the chamber powder inlet of the single powder conveyor chamber can be fluidly connected or connectable to the powder inlet of the dense phase powder pump; and
a powder outlet valve by means of which the chamber powder outlet of the single powder conveyor chamber can be fluidly connected or connectable to powder outlet of the dense phase powder pump;
wherein the powder inlet is arranged at a first end region of the dense phase powder pump and the powder outlet at an oppositely situated second end region of the dense phase powder pump;

wherein the single powder conveyor chamber is arranged between the powder inlet and powder outlet of the dense phase powder pump, and has a chamber powder inlet on a first end region and a chamber powder outlet on an oppositely situated second end region;
wherein the powder outlet of the single powder conveyor chamber is or can be fluidly connected to the powder outlet of the dense phase powder pump by means of the powder outlet valve; and
wherein the single powder conveyor chamber comprises a chamber wall, wherein the chamber wall of the single powder conveyor chamber is formed at least over part of its length by a filter which surrounds the single powder conveyor chamber and separates it the single powder convey or chamber from an intermediate chamber surrounding the filter and formed between the filter and a powder conveyor chamber housing, wherein the filter is permeable to gas but not to coating powder.

12. The dense phase

Assignees

• Gema Switzerland Gmbh

Inventors

• Mauchle Felix
• Vieli Hanspeter
• Lüthi Hans-Peter

Classifications

• B65G53/60

  Devices for separating the materials from propellant gas · CPC title

• B65G53/18

  through a porous wall · CPC title

• B05B7/1404

  Arrangements for supplying particulate material · CPC title

• B65G53/30

  Conveying materials in bulk through pipes or tubes by liquid pressure · CPC title

• F04F1/02

  using both positively and negatively pressurised fluid medium, e.g. alternating · CPC title