APPARATUS AND METHOD FOR DISPENSING A MIXTURE OF A GAS AND A FLUID MATERIAL

• US 20080197209A1
• Filed: 11/13/2007
• Published: 08/21/2008
• Est. Priority Date: 02/16/2007
• Status: Active Grant

• Current Assignee: Nordson Corporation
• Original Assignee: Nordson Corporation
• Inventors: Ganzer, Charles P.
• Granted Patent: US 7,703,705 B2
• Time in Patent Office: Days
• US Class Current: 239/8
• CPC Class Codes: B05B 7/0416 with arrangements for mixing one gas and one liquid
• CPC Class Codes: B05B 7/0483 with gas and liquid jets intersecting in the mixing chamber
• CPC Class Codes: B05B 7/1254 the controlling means being fluid actuated
• CPC Class Codes: B05B 7/32 the fed liquid or other fluent material being under pressure
• CPC Class Codes: B29B 7/726 Measuring properties of mixture, e.g. temperature or density B29B7/724 takes precedence
• CPC Class Codes: B29B 7/7409 with supply of gas
• CPC Class Codes: B29B 7/7419 with static or injector mixer elements
• CPC Class Codes: B29B 7/7621 involving introducing a gas or another component in at least one of the components
• CPC Class Codes: B29B 7/7642 Adjustable feed orifices, e.g. for controlling the rate of feeding
• CPC Class Codes: B29B 7/823 Temperature control
• CPC Class Codes: B29B 7/826 Apparatus therefor
• CPC Class Codes: B29C 44/3446 Feeding the blowing agent
• CPC Class Codes: B29C 44/461 dispensing apparatus, e.g. dispensing foaming resin over the whole width of the moving surface

Abstract

Apparatus and methods for generating and dispensing a mixture containing a pressurized gas and a fluid material. The apparatus includes a mixing device having a mixing chamber and a mixer inside the mixing chamber. A gas injection device, which is coupled with the mixing device, injects the pressurized gas into the fluid material in the mixing chamber. The mixer operates to combine the pressurized gas with the fluid material to form a mixture, which is subsequently dispensed from a dispenser coupled with the mixing device.

Claims

1. A gas injection device comprising:

a main body having an inlet configured to receive a pressurized gas, an outlet configured to exhaust the pressurized gas, a gas passage connecting said inlet and said outlet, and a control orifice in said gas passage, said control orifice configured to meter a flow rate of the pressurized gas to said outlet; and

a flow control element in said gas passage, said flow control element having a first condition in which the pressurized gas can flow in said gas passage from said inlet through said control orifice to said outlet and a second condition in which the pressurized gas is blocked from flowing to said outlet.

2. The gas injection device of claim 1 wherein said flow control element is located in said gas passage between said control orifice and said outlet.

3. The gas injection device of claim 1 wherein said flow control element includes a plunger, a seat between said outlet and said control orifice, and a biasing element applying a biasing force that urges said plunger into contact with said seat, said plunger movable relative to said seat to provide the first and second conditions of said flow control element.

4. The gas injection device of claim 3 wherein said plunger is movable relative to said seat to provide the first condition when a fluid pressure between said plunger and said inlet exceeds a sum of the biasing force and a fluid pressure between said plunger and said outlet, and said plunger movable to provide the second condition when the fluid pressure between said plunger and said outlet exceeds the sum of the biasing force and the fluid pressure between said plunger and said inlet.

5. The gas injection device of claim 4 wherein said plunger has a non-contacting relationship with said seat in said first condition of said flow control element, and said plunger has a contacting relationship with said seat in said second condition of said flow control element.

6. The gas injection device of claim 3 wherein said main body further includes a gas chamber between said seat and said control orifice.

7. The gas injection device of claim 6 wherein said gas chamber has a volume of about one cubic centimeter or less.

8. The gas injection device of claim 1 wherein said body includes a sealing seat in said gas passage between said inlet and said outlet, and further comprising:

a needle tip movable relative to said sealing seat between an open position in which said needle tip is separated from said sealing seat to permit the pressurized gas to flow past said sealing seat and a closed position in which said needle tip contacts said sealing seat to block a flow of the pressurized gas; and

an actuator mechanically coupled with said needle tip, said actuator adapted to move said needle tip relative to said sealing seat between said open and closed positions.

9. The gas injection device of claim 8 wherein said control orifice is located between said sealing seat and said outlet.

10. The gas injection device of claim 1 wherein said control orifice has an effective diameter of about 0.001 inches to about 0.002 inches.

11. An apparatus for dispensing a mixture of a pressurized gas and a fluid material, the apparatus comprising:

a mixing device including a mixing chamber confining a stream of the fluid material and a mixer inside said mixing chamber, said mixer configured to combine the pressurized gas with the stream of the fluid material to form the mixture;

a dispenser coupled in fluid communication with said mixing chamber, said dispenser configured to receive and dispense the mixture; and

a gas injection device having an inlet configured to receive the pressurized gas, an outlet coupled with said mixing chamber of said mixing device, and a gas passage between said inlet and said outlet, said gas injection device configured to communicate the pressurized gas from said inlet through said gas passage to said outlet and from said outlet into said mixing chamber.

12. The apparatus of claim 11 wherein said gas injection device further includes a sealing seat in said gas passage between said inlet and said outlet, a needle tip, and an actuator coupled with said needle tip, said actuator configured to move said needle tip relative to said sealing seat between an open position in which said needle tip is separated from said sealing seat to permit the pressurized gas to flow past said sealing seat and a closed position in which said needle tip contacts said sealing seat to block a flow of the pressurized gas.

13. The apparatus of claim 12 further comprising:

a control system electrically coupled with said actuator of said gas injection device, said control system configured to cause said actuator to move said needle tip from the closed position to the open position when said dispenser is operated to dispense the mixture.

14. The apparatus of claim 11 wherein said gas injection device includes a flow control element includes a plunger, a seat between said outlet and said control orifice, and a biasing element applying a biasing force that urges said plunger into contact with said seat, said plunger movable relative to said seat to provide a first condition in which the pressurized gas can flow in said gas passage from said inlet through said control orifice to said outlet and a second condition in which the pressurized gas is blocked from flowing to said outlet.

15. The apparatus of claim 14 wherein said plunger is movable relative to said seat to provide the first condition when a fluid pressure of the pressurized gas between said plunger and said inlet exceeds a sum of the biasing force and a fluid pressure of the fluid material between said plunger and said outlet, and said plunger movable to provide the second condition when the fluid pressure of the pressurized gas between said plunger and said outlet exceeds the sum of the biasing force and the fluid pressure of the fluid material between said plunger and said inlet.

16. The apparatus of claim 11 wherein said injection device includes a control orifice located in said gas passage between said inlet and said outlet, said control orifice configured to meter a flow rate of the pressurized gas to said outlet.

17. The apparatus of claim 11 further comprising:

a control system electrically coupled with the dispenser and with said gas injection device, said control system operative to regulate injection of the pressurized gas from said gas injection device into the fluid material in said mixing chamber.

18. A method for dispensing a mixture of a fluid material and a pressurized gas, the method comprising:

injecting the pressurized gas into a stream of the fluid material flowing through a mixing chamber;

combining the pressurized gas with the fluid material inside the mixing chamber to form the mixture; and

dispensing the mixture.

19. The method of claim 18 further comprising:

discontinuing the dispensing of the mixture to interrupt the stream of the fluid material so that the fluid material is static inside the mixing chamber; and

discontinuing the injection of the pressurized gas into the static fluid material when the stream of the fluid material is interrupted.

20. The method of claim 18 wherein injecting the gas further comprises:

actuating a gas injection device to selectively cause the pressurized gas to be injected into the mixing chamber.

21. The method of claim 20 wherein injecting the gas further comprises:

metering a flow rate of the pressurized gas with a control orifice when the gas injection device is selectively actuated to an open condition in which the pressurized gas is injected into the stream of the fluid material.

22. The method of claim 21 further comprising:

preventing back flow of the fluid material to the control orifice of the gas injection device when the gas injection device is selectively actuated to a closed condition to interrupt the injection of pressurized gas into the fluid material.

23. The method of claim 20 further comprising:

interrupting the stream of the fluid material through the mixing chamber; and

discontinuing the injection of the pressurized gas into the fluid material by causing the gas injection device to selectively actuate to a closed condition when the stream of the fluid material is interrupted

24. The method of claim 18 wherein injecting the gas further comprises:

controlling a flow rate of the pressurized gas into the fluid material.

25. The method of claim 18 further comprising:

preventing back flow of the fluid material into a gas injection device configured to inject the pressurized gas into the mixing chamber.