Vapor phase decontamination of containers

• US 20020159915A1
• Filed: 02/15/2002
• Published: 10/31/2002
• Est. Priority Date: 02/16/2001
• Status: Active Grant

• Current Assignee: American Sterilizer Company (Steris Corporation)
• Original Assignee: Steris Corporation
• Inventors: Hill, Aaron L., McDonnell, Gerald E., McVey, Iain F., Zelina, Francis J., Buczynski, Peter J., Mielnik, Thaddeus
• Granted Patent: US 7,186,374 B2
• Time in Patent Office: Days
• US Class Current: 422/3
• CPC Class Codes: A61L 2/186 Peroxide solutions
• CPC Class Codes: A61L 2/208 Hydrogen peroxide
• CPC Class Codes: A61L 2202/23 Containers, e.g. vials, bottles, syringes, mail
• CPC Class Codes: B65B 55/025 Packaging in aseptic tunnels
• CPC Class Codes: B65B 55/10 by liquids or gases
• CPC Class Codes: B67C 7/0073 Sterilising, aseptic filling and closing B67C3/2642 takes precedence

Abstract

A flash vapor generator (10) provides a constant flow of vaporized hydrogen peroxide for rapidly sterilizing a large decontamination tunnel (11) with a high container throughput. The vaporizer includes a heated block which defines an interior bore or bores. The conditions within the decontamination tunnel are carefully monitored to avoid condensation of the vapor while maintaining the vapor as close as possible to the saturation limit.

Claims

1. A vapor decontamination system for decontaminating a plurality of items, the system comprising:

a flash vaporizer for vaporizing into a vapor a liquid which includes an antimicrobial;

a means for introducing the liquid from a source to the flash vaporizer;

a first duct along which a carrier gas passes, the first duct being fluidly connected with at least one fill line which selectively supplies vapor and carrier gas to at least one of the items;

a second duct, fluidly connected with an outlet of the vaporizer, for supplying the vapor into the first duct for mixing into the carrier gas passing through the first duct.

2. The system of claim 1, wherein the items include containers defining an interior space and a discharge outlet of the at least one fill line is selectively positionable such that the interior space of each of the items receives the vapor.

3. The system of claim 2, wherein the discharge outlet of the at least one fill line is selectively positionable in the interior space of each of the items.

4. The system of claim 2, further including a means for withdrawing the vapor from the container interior space.

5. The system of claim 4, further including:

an enclosure which receives the items; and

the means for withdrawing includes a vacuum pump which draws a vacuum on the enclosure, such that vapor is drawn from the container interior space.

6. The system of claim 4, wherein the means for withdrawing includes:

an exhaust line having an inlet which is selectively receivable in the interior space; and

a vacuum pump for applying a vacuum to the exhaust line to withdraw the vapor from the interior space.

7. The system of claim 6, further including:

a means for selectively fluidly connecting the vacuum pump with the exhaust line, whereby the vapor is allowed to remain in the interior space for a period of time sufficient to effect microbial decontamination before withdrawal.

8. The system of claim 3, further including:

a cap associated with the fill line which selectively closes an opening to the interior space of the item during supply of vapor and carrier gas to the interior space.

9. The system of claim 8, wherein the cap receives the fill line and an exhaust line therethrough.

10. The system of claim 1, further including a conveyor system which conveys the items past the at least one fill line.

11. The system of claim 10, further including a reciprocating manifold which sequentially raises and lowers the at least one fill line as the items pass by.

12. The system of claim 1, further including a vapor withdrawal system, the vapor withdrawal system including at least one exhaust line which is selectively

positioned within the at least one item, whereby vapor is withdrawn from the item.

13. The system of claim 1, wherein:

the items are partially set parisons;

the system further includes a mold in which the parison is formed into a container; and

the carrier gas is supplied at sufficient pressure to mold the parison.

14. The system of claim 1, wherein the antimicrobial compound includes hydrogen peroxide and the flash vaporizer includes:

a metal block;

at least one heater for heating and maintaining the metal block at or above a vaporization temperature of hydrogen peroxide and below a hydrogen peroxide disassociation temperature; and

a passage extending through the block from an inlet to the outlet.

15. The system of claim 14, wherein the passage expands in cross section between the inlet and the outlet.

16. The system of claim 14, wherein the passage turns at least 180°

between the inlet and the outlet.

17. The system of claim 16, wherein the passage includes at least two turns of approximately 90°

and a wall therebetween, such that the liquid in the passage strikes the wall, thereby increasing a vaporization rate of the liquid antimicrobial compound.

18. The system of claim 16, wherein the passage includes:

a plurality of interconnected bores extending back and forth through the block between the inlet and the outlet.

19. The system of claim 1, further including:

a heater and a dehumidifier connected with the first duct upstream from the second duct.

20. The system of claim 1, further including:

a source of carrier gas connected with the flash vaporizer inlet for supplying a stream of carrier gas to the vaporizer.

21. The system of claim 1, further including:

a plurality of fill lines;

at least one additional flash vaporizer and means for introducing liquid fluidly connected with at least one of the plurality of fill lines.

22. The system of claim 1, further including:

a monitor for monitoring concentration of the antimicrobial in an environment around the item; and

a controller connected to the monitor for controlling the means for introducing liquid in accordance with monitored conditions.

23. The system of claim 1, wherein the means for introducing includes a metering pump.

25. The method of claim 24, wherein the antimicrobial vapor includes hydrogen peroxide and further including:

heating a block which has an internal passage to a temperature sufficient to vaporize liquid hydrogen peroxide but which temperature is lower than a temperature which disassociates hydrogen peroxide;

passing liquid hydrogen peroxide into the passage through the block to vaporize the liquid hydrogen peroxide;

passing the hydrogen peroxide vapor from the passage into the mixing zone; and

mixing the hydrogen peroxide vapor into the carrier gas flow.

26. The method of claim 25, further including:

blowing carrier gas through the passage with the hydrogen peroxide.

27. The method of claim 26, wherein a flow rate of carrier gas through the passage is less half of the flow rate of carrier gas in the duct.

28. The method of claim 24, further including:

pulling carrier gas with antimicrobial vapor from the defined region.

29. The method of claim 24, further including:

monitoring a concentration of the antimicrobial compound in the vapor in the defined region; and

controlling a rate at which the vapor is supplied to the defined region in accordance therewith.

30. The method of claim 24, further including:

selectively positioning at least one fill line fluidly connected with the duct in an interior space of the containers such that the interior space of the containers receives the vapor.

31. The method of claim 24, further including, selectively positioning at least one exhaust line fluidly connected with a source of vacuum in the interior space of the containers such that the vapor is withdrawn from the interior space.

32. The method of claim 30, further including:

sealing an opening of the container during the step of selectively positioning the at least one fill line to inhibit flow of vapor from the enclosed space through the opening.

33. The method of claim 30, further including:

sequentially raising and lowering the at least one fill line as the containers pass by.

34. The method of claim 24, further including:

heating the containers prior to the step of conveying the coontainers through the defined region, whereby condensation of the vapor on the containers is reduced.

36. The method of claim 35, wherein the flow rate of the first stream is less than 10% of the flow rate of the second stream.

24. A method of decontaminating containers in an defined region, the method comprising:

conveying the containers through the defined region;

pumping a carrier gas through a duct to the defined region;

injecting an antimicrobial vapor into the duct at a mixing zone upstream of the defined region.

35. A method of decontaminating items comprising:

conveying the items through a defined region;

providing a first carrier gas stream and a second carrier gas stream, the first stream having a lower flow rate than the second stream;

introducing the first stream to a passage;

introducing a flow of an aqueous solution of an antimicrobial into the passage, the aqueous solution mixing with the first stream, walls of the passage being heated to vaporize the aqueous solution;

mixing the vaporized aqueous solution and first carrier gas stream with the second carrier gas stream in a mixing zone downstream of the passage;

introducing the mixed vaporized aqueous solution and first and second carrier gas streams to the defined region; and

contacting the items with the antimicrobial.