Filter assembly for a reprocessor

• US 7,569,182 B2
• Filed: 07/27/2006
• Issued: 08/04/2009
• Est. Priority Date: 08/01/2003
• Status: Active Grant

• Current Assignee: American Sterilizer Company (Steris Corporation)
• Original Assignee: American Sterilizer Company (Steris Corporation)
• Inventors: Burke, Peter A., Zelina, Francis J., Kral, Jude A., Ludwig, Karl F.
• Primary Examiner(s): McKane; Elizabeth L
• Application Number:
  US11/494,341
• Publication Number:
  US 20060280647A1
• Time in Patent Office: 1,104 Days
• Field of Search: None
• US Class Current: 422/28
• CPC Class Codes: A61L 2/022 Filtration
• CPC Class Codes: A61L 2/16 using chemical substances
• CPC Class Codes: A61L 2/18 Liquid substances or solutions comprising solids or dissolved gases
• CPC Class Codes: C02F 1/001 Processes for the treatment of water whereby the filtration technique is of importance C02F1/44 takes precedence; construction of filters in general B01D24/00 - B01D41/00
• CPC Class Codes: C02F 1/02 by heating methods of steam generation F22B; preheating boiler feed-water or accumulating preheated boiler feed-water F22D
• CPC Class Codes: C02F 1/32 with ultraviolet light
• CPC Class Codes: C02F 1/44 by dialysis, osmosis or reverse osmosis general membrane separation processes B01D61/00, membrane modules B01D63/00, electrodialysis C02F1/4693, combination of membrane modules and bioreactors C02F3/1268
• CPC Class Codes: C02F 1/444 by ultrafiltration or microfiltration
• CPC Class Codes: C02F 1/50 by addition or application of a germicide or by oligodynamic treatment C02F1/4606, C02F1/467, C02F1/76 take precedence
• CPC Class Codes: C02F 1/688 Devices in which the water progressively dissolves a solid compound
• CPC Class Codes: C02F 1/722 Oxidation by peroxides
• CPC Class Codes: C02F 2301/08 Multistage treatments, e.g. repetition of the same process step under different conditions
• CPC Class Codes: C02F 9/00 Multistage treatment of water, waste water or sewage
• CPC Class Codes: C02F 9/20 Portable or detachable small-scale multistage treatment devices, e.g. point of use or laboratory water purification systems

Abstract

The present invention provides a method of operating a reprocessor that has a chamber for receiving items to be sterilized. The reprocessor is filled with water that has passed through a first and a second filter element that both comprise a filtration system. A liquid sterilant is generated by mixing the water with dry chemical reagents. The liquid sterilant is circulated through a fluid circulation system and the filtration system wherein a portion of the liquid sterilant is directed through a bypass conduit and another portion is directed through the first and second filter elements. After a predetermined exposure time, the reprocessor is drained. Then the reprocessor is filled with water for rinsing that has passed through the first and the second filter elements. The water for rinsing is heated prior to being introduced into the reprocessor.

Claims

1. A method of operating a sterilizer having a chamber for receiving items to be sterilized, a fluid circulation system for circulating fluids through said chamber, means for generating a liquid sterilant from dry chemical reagents by mixing water therewith, and a water filtration system for filtering water entering said sterilizer, said filtration system including:

a fluid feed line that is attached to said chamber, a directional valve disposed in said fluid feed line, a first filter element in said fluid feed line, for filtering fluids therethrough, said first filter element located between said directional valve and said chamber and downstream of said directional valve, a second filter element in said fluid feed line for filtering fluids flowing therethrough, said second filter element located between said first filter element and said chamber, a water line connected to said fluid feed line at an intersection located between said directional valve and said first filter element, and a bypass line connected to said fluid feed line to define a fluid path that bypasses said directional valve and said first and second filter elements, said method of operating comprising the steps of;

filling said sterilizer with water from a water source, by passing said water through said first and second filter elements;

generating a liquid sterilant by mixing water filtered by said first and second filter elements with said dry chemical reagents;

circulating said liquid sterilant through said fluid circulation system and said filtration system wherein a portion of said liquid sterilant is directed through said first and second filter elements, and a portion is directed through said bypass conduit;

draining said sterilizer after a predetermined exposure time;

passing water for rinsing from said water line through said first and second filter elements;

heating said water for rinsing after said water for rinsing has passed through said first and second filter elements; and

introducing said water for rinsing into said chamber.

2. A method of operating a sterilizer as defined in claim 1, wherein said second filter element is capable of filtering smaller particles than said first filter element.

3. A method of operating a sterilizer as defined in claim 1, further comprising the step of exposing said water for rinsing to UV radiation before said water for rinsing passes through said first and second filter elements.

4. A method of operating a sterilizer as defined in claim 1, further comprising the step of testing the integrity of said filter elements after each sterile processing phase.

5. A method of operating a sterilizer as defined in claim 1, wherein said water for rinsing is heated to a temperature of from about 40°

C. to about 95°

C.

6. A method of operating a sterilizer as defined in claim 1, wherein said water for rinsing is heated to a temperature of from about 55°

C. to about 85°

C.

7. A method of operating a sterilizer as defined in claim 1, wherein said water for rinsing is heated to a temperature of from about 75°

C. to about 85°

C.

8. A method of operating a reprocessor having a chamber for receiving items to be microbially deactivated, a fluid circulation system for circulating fluids through said chamber, means for generating a microbial deactivation fluid from dry chemical reagents by mixing water therewith, and a water filtration system for filtering water entering said reprocessor, said filtration system including:

a fluid feed line connectable to a source of pressurized water, a first filter element and a second filter element in said fluid feed line, said second filter element disposed in said fluid feed line downstream from said first filter element, and a bypass line connected to said fluid feed line to define a fluid path that bypasses said first and second filter elements, said water filtration system being connected to said fluid circulation system, said method of operating comprising the steps of;

filling said reprocessor with water from a water source, by passing said water through said first and second filter elements;

generating a microbial deactivation fluid by mixing water filtered by said first and second filter elements with said dry chemical reagents;

circulating said microbial deactivation fluid through said fluid circulation system and said filtration system wherein a portion of said microbial deactivation fluid is directed through said fluid feed line and another portion is directed through said first filter element and said second filter element;

draining said reprocessor after a predetermined exposure time;

filling said reprocessor with water for rinsing, by passing said water for rinsing through said first and second filter elements; and

heating said water for rinsing prior to introduction of said water for rinsing into said chamber.

9. A method of operating a reprocessor as defined in claim 8, wherein said second filter element is capable of filtering smaller particles than said first filter element.

10. A method of operating a reprocessor as defined in claim 8, further comprising the step of exposing said water to UV radiation before said water for rinsing passes through said first and second filter elements.

11. A method of operating a reprocessor as defined in claim 8, further comprising the step of testing the integrity of said filter elements after each microbially deactivated processing phase.

12. A method of operating a reprocessor as defined in claim 8, wherein said water for rinsing is heated to a temperature of from about 40°

C. to about 95°

C.

13. A method of operating a reprocessor as defined in claim 8, wherein said water for rinsing is heated to a temperature of from about 55°

C. to about 85°

C.

14. A method of operating a reprocessor as defined in claim 8, wherein said water for rinsing is heated to a temperature of from about 75°

C. to about 85°

C.

15. A method of operating a reprocessor having a chamber for receiving items to be microbially deactivated, a fluid circulation system for circulating fluids through said chamber, means for generating a microbial deactivation fluid from dry chemical reagents by mixing water therewith, and a water filtration system for filtering water entering said reprocessor, said filtration system including:

a fluid feed line connectable to a source of pressurized water, a first filter element and a second filter element in said fluid feed line, said second filter element being downstream from said first filter element, a heater being downstream of said first and said second filter elements and a bypass line connected to said fluid feed line to define a fluid path that bypasses said first and second filter elements and said heater, said water filtration system being connected to said fluid circulation system, said method of operating comprising the steps of;

filling said sterilizer with water from a water source, by passing said water through said first and second filter elements;

generating a liquid sterilant by mixing said filtered water with said dry chemical reagents;

circulating said liquid sterilant through said fluid circulation system and said filtration system wherein a portion of said liquid sterilant is directed through said fluid feed line and another portion is directed through said first filter element and said second filter element to produce filtered liquid sterilant; and

operating said heater during said circulating step.

16. A method of operating a sterilizer as defined in claim 15, wherein said second filter element is capable of filtering smaller particles than said first filter element.

17. A method of operating a reprocessor as defined in claim 15, further comprising the step of exposing said water to UV radiation before said water passes through said first and second filter elements.

18. A method of operating a reprocessor as defined in claim 15, further comprising the step of testing the integrity of said filter elements after each microbially deactivated processing phase.

19. A method of operating a reprocessor as defined in claim 15, wherein said water for rinsing is heated to a temperature of from about 40°

C. to about 95°

C.

20. A method of operating a reprocessor as defined in claim 15, wherein said water for rinsing is heated to a temperature of from about 55°

C. to about 85°

C.

21. A method of operating a reprocessor as defined in claim 15, wherein said water for rinsing is heated to a temperature of from about 75°

C. to about 85°

C.

22. A method of operating a reprocessor as defined in claim 15, wherein said heater is operated to heat said filtered water during said step of filling said sterilizer.

23. A method of operating a reprocessor as defined in claim 22, further comprising the step of exposing said water to UV radiation before said water passes through said first and second filter elements.

24. In a reprocessor having a circulation system for circulating a liquid sterilant or microbial deactivation fluid through a chamber that forms a part of said circulation system, a water filtration system for filtering water used in said reprocessor, said water filtration system, comprising:

a fluid feed line forming a portion of said circulation system, one end of said fluid feed line in fluid communication with said chamber;

a directional valve disposed in said fluid feed line;

a first filter element disposed in said fluid feed line for filtering fluids flowing therethrough, said first filter element located upstream from said chamber;

a second filter element disposed in said fluid feed line for filtering fluids flowing therethrough, said second filter element located between said first filter element and said chamber;

a water line connectable to a source of pressurized water, said water line connected to said fluid feed line at a location between said directional valve and said first filter element; and

a bypass line connected to said fluid feed line to define a fluid path that bypasses said first and second filter elements, said bypass line connected at one end to said fluid feed line upstream of said directional valve and connected at another end to said fluid feed line between said second filter element and said chamber.

25. A reprocessor as defined in claim 24, further comprising valve means operable to isolate said first and second filter elements from said circulation system and from each other.

26. A reprocessor as defined in claim 24, further comprising means for determining the integrity of said first and second filter elements.

27. A reprocessor as defined in claim 26, wherein said means for determining the integrity of said first and second filter elements includes a first differential pressure sensing device operable to sense a pressure differential across said first filter element, and a second differential pressure sensing device operable to sense a pressure differential across said second filter element.

28. A reprocessor as defined in claim 27, wherein said means for determining the integrity of said first and second filter elements includes:

means for isolating each filter element from said filtration system,

means for pressurizing the upstream side of each of said isolated filter elements, and

means for determining the integrity of each filter element based upon the rate of the pressure drop through said isolated filter element over time.

29. A reprocessor as defined in claim 24, wherein said first and second filter elements are disposed within a single filter housing.

30. A reprocessor as defined in claim 24, wherein said first and second filter elements are disposed within separate filter housings and said second filter housing is downstream from said first filter housing.

31. A reprocessor as defined in claim 24, wherein said second filter element is capable of filtering smaller particles than said first filter element.

32. A reprocessor as defined in claim 24, wherein all water entering said reprocessor from said water line first passes through said filter elements, and a portion of all fluid circulated through said circulation system passes through said fluid feed line and said filter elements.

33. A method of operating a sterilizer having a chamber for receiving items to be sterilized, a fluid circulation system for circulating fluids through said chamber, means for generating a liquid sterilant from dry chemical reagents by mixing water therewith, and a water filtration system for filtering water entering said sterilizer, said filtration system including:

a fluid feed line that is attached to said chamber, a directional valve disposed in said fluid feed line, a first filter element disposed in said fluid feed line for filtering fluids therethrough, said first filter element located between said directional valve and said chamber and downstream of said directional valve, a second filter element disposed in said fluid feed line for filtering fluids flowing therethrough, said second filter element located between said first filter element and said chamber, a water line connected to said fluid feed line at an intersection located between said directional valve and said first filter element, and a bypass line connected to said fluid feed line to define a fluid path that bypasses said directional valve and said first and second filter elements, said method of operating comprising the steps of;

filling said sterilizer with water from a water source, by passing said water through said first and second filter elements;

generating a liquid sterilant by mixing water filtered by said first and second filter elements with said dry chemical reagents; and

circulating said liquid sterilant through said fluid circulation system and said filtration system wherein a portion of said liquid sterilant is directed through said first and second filter elements, and a portion is directed through said bypass conduit.

34. A method of operating a sterilizer as defined in claim 33, further comprising the step of exposing said water to UV radiation before said water passes through said first and second filter elements.

35. A method of operating a sterilizer as defined in claim 33, wherein a step of testing the integrity of said filter elements follows the circulating step.

36. A method of operating a sterilizer as defined in claim 33, wherein said second filter element is capable of filtering smaller particles than said first filter element.

37. In a reprocessor having a chamber for receiving items to be microbially deactivated or sterilized, a fluid circulation system for circulating fluids through said chamber, means for generating a microbial deactivation fluid from dry chemical reagents by mixing water therewith, and a water filtration system for filtering water entering said reprocessor, said filtration system including:

a fluid feed line connectable to a source of pressurized water, a first filter element and a second filter element in said fluid feed line, said second filter element being downstream from said first filter element, a method of checking the integrity of at least one of said filter elements, comprising the steps of;

a) establishing a first known pressure on the upstream side of said filter element;

b) allowing pressure on said upstream side of said filter element to dissipate through said filter element and through a leak orifice of known dimensions;

c) monitoring over time the change in pressure on the upstream side of said filter;

d) establishing a second known pressure on the upstream side of said filter element;

e) allowing pressure on said upstream side of said filter element to dissipate through said filter element;

f) monitoring over time the change in pressure on the upstream side of said filter; and

g) determining a flow rate through said filter based on the changes in pressure determined in steps c) and f).

38. A method as defined in claim 37, further comprising the step of conducting a pressurized leak test prior to step a).

39. A method as defined in claim 37, further comprising the step of conducting a test on said leak orifice prior to step a).

40. A method as defined in claim 37, wherein the change in pressure on the upstream side of said first and second filter elements is accomplished by using a first and second differential pressure sensing device, said first differential pressure sensing device measuring the difference in the pressure between the upstream side of said first element and the pressure in a control pressure zone, said second differential pressure sensing device measuring the difference in the pressure on the upstream side of said second element to the pressure in said control pressure zone.

41. A method as defined in claim 37, wherein said second filter element is capable of filtering smaller particles than said first filter element.