MULTI-STAGE PROCESS CHALLENGE DEVICE, INDICATOR SYSTEM AND PROCESS CHALLENGE DEVICE SYSTEM

Abstract

Process challenge device (2), especially for simulating the worst-case penetration conditions of a load inside a sterilization chamber, comprising a detector volume (90) for housing a biological, chemical or physical indicator (140), whereby said detector volume (90) is arranged at a dead end of a series of gas volumes (110, 14, 118), whereby said process challenge device (2) comprises two parts (6, 14), namely a housing part (6) and an insertion part (14), whereby said insertion part (14) is at least partially insertable into said housing part (6) in such a way that said detector volume (90) is arranged without any seal inside said both parts (6, 14).

Claims

1. Process challenge device (2), especially for simulating the worst-case penetration conditions of a load inside a sterilization chamber, comprising a detector volume (90) for housing a biological, chemical or physical indicator (140), whereby said detector volume (90) is arranged at a dead end of a series of gas volumes (110, 114, 118), characterized in that said process challenge device (2) comprises two parts (6, 14), namely a housing part (6) and an insertion part (14), whereby said insertion part (14) is at least partially insertable into said housing part (6) in such a way that said detector volume (90) is arranged without any seal inside said both parts (6, 14).

2. Process challenge device (2) according to claim 1 , whereby said two parts (6, 14) fit into each other without sealing and form, combined together, in series connected volumes (110, 114, 118) for providing specific penetration characteristics for sterilization agents where the gas entrance inlet/outlet is between the connection of the housing and insertion part.

3. Process challenge device (2) according to claim 1, whereby said series of volumes (110, 114, 118) provides connected channels, whereby one end of said channels is connectable to a sterilization chamber and the other end is connected to said detector volume (90) which is configured to house, alternatively one or more chemical, biological, or physical indicators for detecting the presence of a sterilizing agent.

4. Process challenge device (2) according to claim 1, whereby said two parts (6, 14) comprise means (120-132; 150) for a force-fit and/or form-fit connection, especially by clicking or snapping together by mechanically fixing their positions.

5. Process challenge device (2) according to claim 4, whereby adjusting means (120-132) are provided for positioning said two parts (6, 14) with respect to each other in a plurality of defined positions with respect to each other by mechanically fixing the position.

6. Process challenge device (2) according to claim 1, whereby said housing (6) and/or said insertion part (14) are made of metal, plastic, or metal-plastic-bonded system.

7. Process challenge device (2) according to claim 1, whereby from an entrance region to said dead end said in series connected gas volumes (110, 114, 118) decrease in volume and/or cross section.

8. Process challenge device (2) according to claim 1, whereby at least one of said parts (6, 14) comprises a round, oval, rectangular, or multi-edge shape.

9. Process challenge device (2) according to claim 1, whereby said series of gas volumes (110, 114, 118) are partially or totally filled with porous material.

10. Process challenge device (2) according to claim 1, whereby said detector volume (90) has a volume of less than 200 microliters, a length between 3 and 6 cm and a cross section between 3 and 5 mm2.

11. Indicator system (144), comprising a process challenge device (2) according to one of the previous claims and at least one chemical, biological, or physical indicator (140) arranged in said detector volume (90).

12. Indicator system (144) according to claim 11, with a biological indicator (140), whereby a carrier of said biological indicator (98, 140) is made from paper, metal, glass fiber, plastic, stainless steel, any plastic foil, Tyvek or any combi-nation, especially in addition being covered with at least one of said materials.

13. Indicator system (144) according claim 11, whereby said indicator (98, 140) is a self-contained biological indicator (SCBI) or a biological indicator strip, whereby a carrier of spores is made of paper, metals, glass, glass fiber, plastic or any combination of said materials.

14. Indicator system (144) according to claim 12, whereby the indicator (98, 140) is a chemical indicator using various carriers like paper, glass fiber, stainless steel or plastic foil like PET, PP or others and is surface-protected or covered on both sides with different chemical indicator colours to be used to monitor different sterilization processes.

15. Process challenge device combination (200), comprising as components two or more insertion parts (14), and two or more housing parts (6), whereby said components are built in such a way that each insertion part (14) can be combined with each housing part (6) for providing a process challenge device (2) according to claim 1, whereby said insertion parts (14) and/or housing parts (6) are built differently such that each combination of insertion part (14) and housing part (6) differs from each other combination in its air removal and sterilant penetration characteristics, which preferably allows to make several different PCD with only a few housing and insertion parts.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0068] Further features and advantages of the present invention shall become clearer from the following detailed description of some of its preferred embodiments, made with reference to the attached schematic drawings and given as an indication and not for limiting purposes.

[0069] In particular, the attached drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification. The drawings together with the description explain the principles of the invention.

[0070] In the drawings, corresponding characteristics and/or components are identified by the same reference numbers. In these drawings:

[0071] FIG. 1 shows a process challenge device with a housing part and an insertion part in a preferred embodiment in a perspective view;

[0072] FIG. 2 shows the housing part in a perspective way;

[0073] FIG. 3 shows a cross section through the housing part and the insertion part in an assembled state;

[0074] FIG. 4 shows the insertion part in a perspective way;

[0075] FIG. 5 shows a cross section through the housing part and the insertion part in an assembled state;

[0076] FIG. 6 shows a cross-sectional view with the insertion part inserted into the housing part;

[0077] FIG. 7 shows another cross-sectional view of the both parts fitted together;

[0078] FIG. 8 shows a housing part of a process challenge device in a second preferred embodiment in a perspective view;

[0079] FIG. 9 shows a cross section through the housing part and the insertion part in an assembled state;

[0080] FIG. 10 shows an insertion part of process challenge device in a further preferred embodiment;

[0081] FIG. 11 shows a cross section through the housing part and the insertion part in an assembled state;

[0082] FIG. 12 shows the insertion part of FIG. 10 fully inserted into a housing part;

[0083] FIG. 13 shows a cross section of the configuration according to FIG. 12;

[0084] FIG. 14 shows the process challenge device according to FIG. 12 with the insertion part loosely inserted into housing part;

[0085] FIG. 15 shows a cross section through the configuration of FIG. 14;

[0086] FIG. 16 shows a detailed view of the insertion part with adjustment means;

[0087] FIG. 17 shows a configuration with the insertion part fully inserted into housing part;

[0088] FIG. 18 shows a first configuration with the insertion part in a first adjusted position;

[0089] FIG. 19 shows a second configuration with the insertion part in a second adjusted position;

[0090] FIG. 20 shows the configuration with an indicator inserted into the detector volume;

[0091] FIG. 21 shows another cross-sectional view of the device;

[0092] FIG. 22 shows a process challenge device in a third preferred embodiment in a perspective view;

[0093] FIG. 23 shows the device of FIG. 22 in a side view;

[0094] FIG. 24 shows a cross-sectional view through the device of FIG. 22;

[0095] FIG. 25 shows a housing part of the device of FIG. 22 in a perspective view;

[0096] FIG. 26 shows the housing part in a cross-sectional view;

[0097] FIG. 27 shows the insertion part of the device of FIG. 22 in a perspective view;

[0098] FIG. 28 shows the inner part in a cross-sectional view;

[0099] FIG. 29 shows a process challenge device in a first cross-sectional view;

[0100] FIG. 30 shows the process challenge device of FIG. 29 in a second cross-sectional view;

[0101] FIG. 31 shows the process challenge device of FIG. 29 in a third cross sectional view;

[0102] FIG. 32 shows three components of a process challenge device system components in a preferred embodiment;

[0103] FIG. 33 shows three further components of a process challenge device system;

[0104] FIG. 34 shows a housing part of the process challenge device according to FIG. 29;

[0105] FIG. 35 shows the component of FIG. 34 in a sectional view;

[0106] FIG. 36 shows the component of FIG. 34 in a further sectional view;

[0107] FIG. 37 shows an insertion part of the process challenge device according to

[0108] FIG. 29 in a first view;

[0109] FIG. 38 shows the component of FIG. 37 in a further view;

[0110] FIG. 39 shows the component of FIG. 37 in a first sectional view; and

[0111] FIG. 40 shows the component of FIG. 37 in a second sectional view.

DETAILED DESCRIPTION

[0112] In FIG. 1, a process challenge device 2 in a preferred embodiment is shown. The process challenge device 2 displayed in FIG. 1 shows a construction scheme de-signed to test the penetration characteristics of a sterilization agent. The knowledge achieved during the use of the test device 2 may be used especially for the verification or testing steam in a sterilization process. Using such a steam sterilization process the instruments or materials to be sterilized are put into a sterilization chamber not specified. At first the sterilization chamber is removed from air. The air removal process can be carried out by a downward gravity displacement process, super- or sub-atmospheric air removal cycles or their combinations. The process challenge device 2 is especially designed to test sterilizing properties of a sterilizing routine. The process challenge device 2 comprises a first or housing part 6 which provides an outer housing or casing 10. Partially and/or fully insertable into the first part 6 is a second or insertion part 14 which comprises a cover 18 for the casing 10.

[0113] Casing 10 has an oval shape which leads a reduced height needed when the process challenge device 2 is arranged in a sterilization chamber. In casing 10, an opening 22 is provided which is an entrance region for a multi-staged gas volume/series of gas volumes in which gas is transported in two opposing directions during the sterilization process and which are arranged in a spatially nested way inside casing 10. Casing 10 preferably comprises a part 26 with a recessed region 30. Casing 10 is closed at a first end 34 and provides an opening 36 at a second end 38 at which cover 18 is arranged on casing 10.

[0114] FIG. 2 shows the housing part 6 with the insertion part 14 removed. Housing part 6 comprises a second duct 42 or shell/hull which is shaped concentric to a common middle axis 48 of duct 42 and casing 10 and comprises an opening 44. Duct 42 is cylindrically shaped and is fixed to a bottom 52 from the inside of casing 10. An interior space of duct 42 is closed at the first end 34. A cross section through housing part 6 and insertion part 14 is shown in FIG. 3.

[0115] In FIG. 4, insertion part 14 which in the mounted position is at least partially insert-ed in housing part 6 is shown in a perspective view. Cover 18 is built as an oval-shaped piece with an end part 60 and an insertion part 64. In a fully inserted state, insertion part 64 is fully inserted in housing 10. In the fully inserted state, a rim 68 (see FIG. 2) of casing 10 serves as a seat for end part 60, which in lateral direction has a larger extension than insertion part 64. Second part 14 comprises a first duct 70 with an oval shape 72. First duct 70 in a mounted position extends into casing 10 in an axial direction 76 and leaves a passage region in the inside of casing 10 at first end 34. Inside first duct 70, a third duct 80 is arranged which has an outer circular shape. In axial direction 76, third duct 80 extends farther than first duct 70. A detector volume 90 with a detector holder 94 is arranged at the part of third duct 80 which preferably projects beyond first duct 70. A top view of second part 14 is shown in FIG. 5.

[0116] In a preferred method of manufacturing a process challenge device 2, the duct 42 is a part separate and separately manufactured from the casing 10. It preferably is cylinder-shaped piece which is put on a corresponding socket in the inside of casing 10. Third duct 80 of insertion part 14 is preferably a part separate and separately manufactured from duct 70. It is preferably inserted into duct 70 and put on a corresponding socket inside of duct 70.

[0117] The detector volume 90 is arranged at a dead end and closed end of casing 10 and is built in a sealing-less way, i.e. it does not comprise any sealing element and/or gasket. This has the advantage that no sealing element is necessary which in known devices needs regular checks and maintenance since a gas leak would render the measurement invalid. A sealing element is typically needed for an opening of the detector chamber for inserting and removing the detector. In the process challenge device 2 shown here, the detector volume 90 is arranged at an end of third duct 80 which is part of second or insertion part 14. When second or insertion part 14 is fully extracted from the first or housing part 6, the indicator/detector can be inserted into the detector volume 90. A separate sealed access to the detector volume 90 is not needed. Moreover, the detector volume 90 is only accessible by gas which has traversed the series of gas volumes provided in casing 10. The design with two parts 6, 14 and the location of detector volume 90 at an end part of second part 14 allows the reliable and sealing-less design shown.

[0118] In FIGS. 6 and 7, two sections through process challenge device 2 are shown in perpendicular orientations of device 2. When the process challenge device 2 is placed in a sterilization chamber, sterilizing agent and/or gas/steam can enter through the opening 22 and flow/move/stream in a direction 100 between first duct 70 and casing 10. More precisely, it will flow between an inner wall of casing 20 and an outer wall of first duct 70 by which a first gas volume 110 is defined. It will then continue to flow inside casing 10 to the first end 34. It will then flow in a direction 102 and continue its way in direction 102 between first duct 70 and second duct 42, i.e. between an inner wall or surface of first duct 70 and an outer wall of second duct 42 and continue in a second gas volume 114. It will then turn around and continue to flow in a direction 104 between first duct 42 and third duct 80 in a third gas volume 118 until it reaches the detector volume 90. In this way, a zig-zag path or passage is defined for the sterilizing agent. The described travel for gas

[0119] describes its way from opening 22 to detector volume 90. In a sterilization process, gas will move in both directions in gas volumes 110, 114, and 118.

[0120] The first passageway or volume 110 or first stage of the gas collection volume in the preferred embodiment has a volume of ca. 50 cm3. The second passageway or volume 114 or second stage of the gas collection volume in the preferred embodiment has a volume of ca. 15 cm.sup.3. The third passageway or volume 118 or third stage of the gas collection volume in the preferred embodiment has a volume of ca. 7 cm.sup.3.

[0121] Only if the sterilizing agent has passed through the whole passage from the entrance of the gas collection volume to the detector volume 90, an indicator/detector 98 placed in detector volume 90 will react to the sterilizing agent. Since the detector volume 90 is only accessible in this way, a high reliability of result if provided. The detector volume 90 does not have to be sealed in order to prevent direct access from sterilizing agent as it is the case in other test devices where the detector chamber has to be opened to insert the detector and has to be closed again, whereby a sealing element/gasket is provided for preventing direct entry of sterilizing agent.

[0122] A housing part 6 of a process challenge device 2 in a second preferred embodiment is shown in FIG. 8. In contrast to the embodiment shown in the previous FIGs, the embodiment according to FIG. 8 does not provide an opening 22 as an entrance for gas. An entrance for gas to enter the series of volumes is made possible in a circumferential gap between both parts 6 and 14. In FIG. 9, first part 6 and second part 14 are shown in a cross section. As shown in FIG. 10, insertion part 14 in axial direction 76 comprises on duct 72 a series of engagement/adjustment elements 120, 122, 124, 126, 128, 130, 132. Adjustment elements 120-132 are preferably arranged equally spaced from each other and preferably comprise respective labels. The respective label preferably indicates a distance by which second part 14 is extracted from second part 14 compared to a fully inserted state.

[0123] Preferably, additional labels 140, 142 are provided which indicate extraction distances. In the present preferred embodiment, labels 140 and 142 indicate the numbers “20” and “10”, respectively, which denote an extraction distance of 20 or 10 millimeters. Adjustment elements 120, 124, 126, 128, 130, 132 are provided with the labels “60”,“50”,“40”,“30”, which again indicate extraction distances in millimeters. Adjustment elements are in the present embodiment build as ramps or teeth which protrude from duct 72 with increasing distance.

[0124] In FIG. 12, insertion part 14 is fully inserted into housing part 6. FIGS. 11 and 13 show cross sections through the parts 6, 14 fitted into each other.

[0125] FIG. 14 displays insertion part 14 adjusted at a specified extraction length in housing part 6. In FIG. 14, end part 60 is tilted by 90 degrees compared to a configuration in which part 14 is engaged with housing part 6 at a specified extraction distance. Preferably, on opposite sides of insertion part 14, adjustment elements 126-132 and labels 140, 142 are provided. In this way, the engagement of insertion part 14 with housing part 6 is symmetric, leading to a better distribution of forces. Additionally, the handling for the user is improved. FIG. 15 shows a cross section of both components and FIG. 16 shows a detailed view of end part 60,

[0126] As can be seen in FIG. 17, on its inner side facing insertion part 14 in the mounted position, housing part 6 comprises protrusions 150 which can engage with adjustment elements 120-132. Preferably, protrusions 150 are arranged on opposite sides of the inner surface of first element 6. Protrusions 150 only cover a semi-circle of the inner circumference of element 6. In this way, when turning the insertion part 14 by a specified angle, protrusions 150 and adjustment elements 120-132 are disengaged.

[0127] In this configuration, insertion part 14 can be freely removed from housing part 6, for example for removing the present indicator and/or inserting a new indicator into detector volume 90 which is essentially built as a slot. Also, in the disengaged position, the extraction length of insertion part 14 with respect to housing part 6 can be chosen. Once the desired extraction length has been chosen and which can be inferred from the corresponding label, insertion part 14 can be turned for an engagement of the corresponding adjustment elements 120-132 with the protrusions 150. In the preferred embodiment, the fully engaged position of insertion element 14 in housing element 6 and the fully disengaged position are reached by a 90-degree rotation of insertion element 14 within housing element 6.

[0128] In FIG. 18, a configuration of insertion part 14 and housing part 6 is shown in which adjustment element 132 is engaged with protrusion 150 in a force-fitting manner. Due to the adjacent adjustment element 130, a movement of insertion part 14 to larger extraction lengths is blocked by protrusion 150.

[0129] FIGS. 19 and 20 show the process challenge device 2 in a second engaged position. In FIG. 20, the inserted indicator 140 is shown. Process challenge device 2 and indicator 144 build an indicator system 144. In FIG. 21, a view of the process challenge device rotated by 90 degrees is shown. With each additional distance by which the insertion part 14 is extracted from the housing part 6, the length of all three volumes which are arranged in series increases.

[0130] In FIGS. 22-28, a process challenge device 2 in further preferred embodiment is shown. In this embodiment, the housing part 6 has circular cross section. Preferably, also this embodiment is built with two parts 6, 14 as described in relation to the previous embodiment and provides a series of three gas volumes. Also, preferably, the design of the two parts 6, 14 in relation to casing and ducts is built as describe above.

[0131] When the insertion part 14 is only partially inserted into housing part 6, the entrance region for gas/steam is provided via a circular gap between end part 60/cover 18 and casing 10. The process challenge device can provide aligning means which allow entering the insertion part 14 into the housing part 6 only in a number of set of directions. If insertion part 14 and housing part 6 are then rotated with respect to each other by a certain angle, the insertion part 14 cannot be extracted from housing part 6. In this way, it can be reliably assured that the insertion part 14 is not released from housing part 6 during the sterilization process. In a preferred variant, in the inside of casing 10/housing part 6, at least one protrusion is arranged and whereby insertion part 14 comprises a collar with at least one recess which allows the passing of the protrusion when the insertion part 14 is inserted into housing part 6.

[0132] The collar is then arranged in a longitudinal direction arranged below said protrusion. When insertion part 14 is turned by a defined angle, the protrusion blocks the collar, thereby preventing in a form-locking manner the release of insertion part 14. Preferably, three protrusions are arranged equally spaced along an inner circumference and the collar comprises three recesses.

[0133] FIGS. 29-31 and 37 to 40 show a process challenge device in a further preferred embodiment. In this embodiment, an inner hull 170 of housing part 6 in an axial direction 176 extends further than an outer hull 172 of casing 6. In this way, the size of at least one gas volume formed between ducts/walls of parts 6/14 is altered in volume compared to the case in which both hulls 170, 172 have the same axial extension.

[0134] In FIG. 32 three different housing elements or housing parts 6 are shown. These housing parts 6 all comprise an identical outer hull 172. They also comprise, respectively, an inner hull 170 which in an assembled state with three insertion parts 14 shown in FIG. 33 form ducts or gas passages for gas which enters the process challenge device. The housing parts 6 shown in FIG. 32 differ in the length of inner duct or hull 170 in an axial direction 176. The housing part 6 shown on the left comprises the longest, the housing part 6 shown on the right comprises the shortest hull 170.

[0135] The three insertion parts 14 shown in FIG. 33 differ by the extension in axial direction 176 of an inner part 180 in which at one end 186 the detection volume 90 is formed.

[0136] Housing parts 6 according to FIG. 32 and insertion parts 14 according to FIG. 33 constitute a process challenge device system 200. Each insertion part shown in FIG. 33 can be inserted in each housing part 6. In this way, nine different process challenge devices 2 can be built which differ from each other in at least one dimension, especially length and/or cross section of a gas volume. This set of process challenge devices therefore allows simulating different sterilization sensitivities. This modular system saves material needed for components. If nine process challenge devices would have to be built separately, nine instead of three housing and insertion parts would be necessary. This system can also be extended easily by adding one or more housing parts 6 and/or insertion parts 14.