GB2321596A

GB2321596A - Sterilising apparatus

Info

Publication number: GB2321596A
Application number: GB9701963A
Authority: GB
Inventors: David Graham Scarr
Original assignee: WORDSWORTH HOLDINGS PLC
Current assignee: WORDSWORTH HOLDINGS PLC
Priority date: 1997-01-30
Filing date: 1997-01-30
Publication date: 1998-08-05
Also published as: GB9701963D0

Abstract

Sterilising apparatus comprises a container 3 which holds matter to be sterilised, means which supply steam to the container and means which cause movement of the container during at least part of the period when steam is in the container. The movement preferably involves rotating the container to and fro about an axis (see arrows) and is caused by a motor (16, Fig 2) driving a belt (17, Fig 2). The container may also be pressurised whilst the steam is present. Preferably the sterilising apparatus forms part of a plant (Fig's 5 and 6) comprising a first region where the matter to be sterilised is loaded into the container, a second region where the container is placed in an autoclave and the matter is sterilised, a third region where the matter is removed from the container and means to transport the container between these regions. Preferably the apparatus is used to treat clinical waste.

Description

STERILISER The present invention relates to sterilising apparatus and a method of sterilising as well as to a sterilisation plant. The present invention is particularly, although not exclusively, applicable to the sterilisation of clinical waste.

The present invention is concerned with the safe disposal of potentially hazardous waste materials (for example, clinical waste material) which cannot be disposed of using conventional methods and apparatus, due to the potentially hazardous properties of the waste products.

Clinical waste is conventionally collected in "yellow bags" in hospitals, which helps to identify the hazardous nature of the contents of the bags. This clinical waste may consist of contaminated "sharps" (for example, scalpel blades and syringe needles), used wound dressings and human tissue. The large volume of these potentially hazardous waste products produced by hospitals presents a problem in the safe disposal of clinical waste. Previous methods have used incineration techniques in order to dispose of clinical waste. However, the introduction of new laws governing the emissions from incinerators, will cause some existing incinerators to be inoperable.

The potential hazards which the emissions from incinerators products, and the present trends for restricting pollutants, suggests that a new technique is preferable to restricting the emitted pollutants.

According to one aspect of the present invention sterilising apparatus comprises a container arranged, in use, to contain matter to be sterilised and steam supply means arranged, in use, to supply steam to the container and container moving means arranged, in use, to cause the container to move during at least part of the period when steam is in the container.

By supplying steam to the container the matter in the container is easily sterilised. By moving the container the matter in the container is broken up and not allowed to form a hard lump that may be very difficult to remove later from the container. As movement of the container causes movement of the matter to be sterilised there need not be any mechanism that has hidden corners that require to be sterilised.

The container may include supporting walls for matter to be sterilised that all face towards a common region.

The internal supporting walls of the container may be unobstructed by inwards protrusions. The container may be arranged to be empty apart from matter to be sterilised.

The internal walls of the container may be substantially smooth.

The apparatus may include support means for the container. The container may be detachably mounted on the support means. The container may be slidably mounted on the support means. The container may be arranged to cooperate with the support means to resist relative movement about at least one axis of rotation. The container may be arranged to cooperate with the support means at at least two spaced locations and preferably three spaced locations. The support means may be arranged to provide a cover for an open region of the container and there may be a gap between the container and the cover of less than 30 mm or less than 20 mm or in the region of or less than 10 mm.

The moving means may be arranged to cause movement of the support means and thereby cause movement of the container. The moving means may be arranged to support the container either directly, or by supporting the support means which in turn support the container.

The moving means may be arranged to cause to and fro movement of the container.

The moving means may be arranged to cause movement of the container about an axis for instance to an extent in the region of 900 to each side of a datum point of that axis.

The moving means may include at least one rotatable driven member. The rotational axis of the driven member may be fixed. Rotation of the driven member in different senses about its axis may be arranged to cause movement of the container in different directions.

The rotatable member may cooperate with part of the apparatus arranged to be moved by the rotatable member to resist relative axial movement of the rotating member and the part that is so cooperated with.

The apparatus may include two rotatable driven members and those members may have any of the features of the rotatable driven member as herein described. A common drive means may be provided for the driven members.

The container may be arranged to be open at the top.

The container may be arranged to be emptied by being upturned. The container may be arranged to be emptied at a different location to the region where the matter in the container is arranged to be sterilised. The container may be arranged to be upturned by apparatus that has any one of the features as hereinbefore described.

The apparatus may include pressurising means arranged to pressurise the container during at least part of the sterilisation.

The volume of the container may be greater than lOm3 and may be in the region of 20m3.

According to another aspect of the present invention a method of sterilising matter comprises locating the matter in a container and supplying steam to the container and causing movement of the container whilst steam is located in the container.

The method may comprise agitating the material in the container during sterilisation.

The method may comprise moving the container to and fro during sterilisation, for instance about an axis.

The method may comprise pressurising the container during sterilisation.

According to a further aspect of the present invention a sterilisation plant includes a first region where matter to be sterilised is located in a container, transportation means arranged to move the matter from the first region to a second region where the matter within the container can be sterilised and transportation means arranged to move the container to a third location where matter in the container that has been sterilised can be emptied therefrom.

The sterilising apparatus at the second region may be as herein described and the method of sterilising the matter may be as herein described.

The method may include two second regions in which matter can be sterilised.

The present invention includes any combination of the herein referred to features or limitations.

The present invention can be carried into practice in various ways but one embodiment will now be described, by way of example and with reference to the accompanying diagrams, in which: Figure 1 is a cross-sectional end view of a roll over unit for load disturbance in an auto-clave; Figure 2 is a cross-sectional side detail view of the gearing mechanism to power the roll over unit for load disturbance in the auto-clave; Figure 3 is a cross-sectional view of the roll over unit showing the central drive wheel and the drive axles; Figure 4 is a side view of the driving wheels, drive axles and driven rings; Figure 5 shows an upper sectional side view and a lower side view of a clinical waste sterilisation plant, and Figure 6 is a plan view of a clinical waste sterilisation plant.

As shown in Figure 1, a cross section through a loaded auto-clave shows an outer cylindrical auto-clave chamber wall 1, a driven ring frame 2 located concentrically within the chamber 2 and a container 3 supported on the ring frame. In use, the ring frame 3 is able to rotate with the chamber and the container 3 is constrained to rotate with the frame 2.

The ring frame 2 is axially fixed in the chamber and is supported along each side by spaced parallel rotatable shafts 4. As shown in Figure 4, each shaft 4 includes axially spaced grooved rollers 5 within which grooves the rim 6 of annular rings 7 of the frame 2 are located and supported.

Each ring 7 of the frame includes top, bottom and side strengthening members 8 that join external parts of the circumference of the ring. Side rails 9 extend axially along the auto-clave to connect each side member 8 of each ring 7. The rails 9 and 10 define inwardly facing axially extending channels 11.

The container 3 includes projecting pins 12 at four spaced locations along each side each having wheels 11.

These wheels 11 locate in the channels of the ring frame to allow the container to be slid axially within the frame but to constrain the container to rotate within the frame.

The shafts 4 that support the ring frame are constrained to rotate in bearings (not shown) at each end region of the chamber. The shafts 4 are connected at their end by belts 14 that pass around a common roller 15, as shown in Figure 3. Rotation of the roller 15 in one direction causes simultaneous clockwise or anticlockwise rotation of the shafts 4 which in turn causes the ring frame to move about its longitudinal axis which in turn causes the container 3 to move.

Figure 2 shows a motor 16 that is connected to the roller 15 by a belt 17. The motor can cause the belt 17 to move in either direction at the required speed and for the required duration. The direction of movement of the belt is also able to be reversed in order to rock or oscillate the container within the chamber.

A typical sterilising process will now be described with the container full or substantially full of bags of clinical waste being located in the sealed chamber.

The chamber is pressurised to 2.6 atmospheres and heated to 1400C with steam being injected into the chamber from a generator having a capacity of 1000 Kg per hour.

These conditions are maintained for a period of 10 minutes during which time the ring frame and the container 3 are caused to rock and fro up to 900 in each direction in a rocking motion either relatively gently or quite vigorously to shake up or agitate the contents of the container. The conditions in the chamber also assist in the destruction of the bags containing the waste. This movement of the container assists in keeping the mass of clinical waste separate rather than allowing it to form one big lump and also assists in the steam being able to reach all of the waste relatively rapidly thereby ensuring complete sterilisation in a relatively short period of time. Alternatively or additionally the pressure being maintained throughout the sterilising process, vacuum and pressure may be alternately applied, for instance in pulses.

The sterilisation process reduces the volume of waste in the container by approximately 70% and typically, 78%.

The volume of the auto-clave chamber is 50m3 and the volume of the container is 20m3.

The process of putting clinical waste into the container, manoeuvring the container to the auto-clave and subsequently retrieving the container from the auto-clave and emptying the sterilised waste will now be described with reference to Figures 5 and 6.

An open topped container 3 is located at the base of a chute 18 in a loading bay 19. Clinical waste from a truck 20 at an average density of 90 Kg/m3 is tipped down the chute into the container 3.

The container 3 is supported, whilst being loaded, on a static frame 21 that provides a rail support for the side wheels 11 of the container. When the container has been filled to the required volume it is grabbed by arms (not shown) and pulled out of the bay on to an adjacent travelling support 22 . The support 22 can then be slid or rolled along rails 23 to align the container 3 with a first or a second auto-clave 24 or 25 before being pushed off the support 22 into the ring frame of the auto-clave.

A plate 10 connected to the rings 2 and extending the length of the frame acts as a lid for the open topped container. The lid is closely spaced to the container at 10 mm to allow the passage of steam and pressure changes but to prevent material from falling out of the container during rocking. The door 26 of the auto-clave is then slide sideways to seal the auto-clave before sterilisation begins.

When sterilisation is complete the auto-clave door is slid open and arms again grab the container and pull it out on to the travelling support. It is then desired to move the support 22 to a lift area 27. However, a further support 28, also slidably mounted on the rails 23 may be in the way. Accordingly the support 22 is aligned with a stationary docking unit 29, on the opposite side of the rails to the loading bay, and the container is pulled on to that unit 29. Then the support 22 is pushed away and the further support 28 is aligned with the docking unit in order to transfer the container to the support 28. The support 28 is then rolled along the rails to bring the container to the lift area.

It can be seen that while one or both of the supports can be active at the same time in order to move two containers simultaneously from the loading bay to an autoclave or from an auto-clave to the docking unit or to the lift area.

As shown in Figure 5, at the lift area 27, the container 3 is slid on to a further ring frame 2 which is then raised. Alternatively the container is lifted on to the further ring frame 2.

The ring frame at the lift areas is then powered to rotate the container through 1800 in order to allow the sterilised waste to drop out of the open container into a discharge chute (not shown) on to a conveyor 30 which then takes the waste to a shredder 31 and compactor 32. The waste is subsequently disposed of at a land-fill site.

The emptied containers are then returned to the loading bay for the cycle to begin again.

It is anticipated that the system described above will be able to sterilise, shred and compact approximately 28 tons of clinical waste per day.

Cleaning of the containers is relatively simple as there are no hidden or obscured parts within the container.

The whole system of moving the containers, including insertion and removal from the auto-claves and including emptying and return of the containers can be automated as can the closure of the doors on the auto-claves and the sterilisation procedure.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

1. Sterilising apparatus comprising a container arranged, in use, to contain matter to be sterilised and steam supply means arranged, in use, to supply steam to the container and container moving means arranged, in use, to cause the container to move during at least part of the period when steam is in the container.

2. Apparatus as claimed in Claim 1 in which the container includes supporting walls for matter to be sterilised that all face towards a common region.

3. Apparatus as claimed in Claim 2 in which the internal supporting walls of the container are unobstructed by inwards protrusions.

4. Apparatus as claimed in any preceding claim in which the container is arranged to be empty apart from matter to be sterilize.

5. Apparatus as claimed in any preceding claim in which the internal walls of the container are substantially smooth.

6. Apparatus as claimed in any preceding claim including support means for the container.

7. Apparatus as claimed in Claim 6 in which the container is detachably mounted on the support means.

8. Apparatus as claimed in Claim 6 or 7 in which the container is slidably mounted on the support means.

9. Apparatus as claimed in any of Claims 6 to 8 in which the container is arranged to cooperate with the support means to resist relative movement about at least one axis of rotation.

10. Apparatus as claimed in any of Claims 6 to 9 in which the container is arranged to cooperate with the support means at at least two spaced locations.

11. Apparatus as claimed in Claim 10 in which the container is arranged to cooperate with the support means at at least three spaced locations.

12. Apparatus as claimed in any of Claims 6 to 11 in which the support means is arranged to provide a cover for an open region of the container.

13. Apparatus as claimed in Claim 12 in which there is a gap between the container and the cover of less than 30 mm.

14. Apparatus as claimed in Claim 13 in which the gap is less than 20 mm.

15. Apparatus as claimed in Claim 14 in which the gap is in the region of or less than 10 mm.

16. Apparatus as claimed in any preceding claim in which the moving means is arranged to cause movement of the support means and thereby cause movement of the container.

17. Apparatus as claimed in any preceding claim in which the moving means is arranged to support the container directly.

18. Apparatus as claimed in any of Claims 1 to 16 in which the moving means is arranged to support the support means which in turn support the container.

i9. Apparatus as claimed in any preceding claim in which the moving means is arranged to cause to and fro movement of the container.

20. Apparatus as claimed in any preceding claim in which the moving means is arranged to cause movement of the container about an axis.

21. Apparatus as claimed in Claim 20 in which the extent of the movement is in the region of 900 to each side of a datum point of that axis.

22. Apparatus as claimed in any preceding claim in which the moving means includes at least one rotatable driven member.

23. Apparatus as claimed in Claim 22 in which the rotational axis of the driven member is fixed.

24. Apparatus as claimed in Claim 22 or 23 in which rotation of the driven member in different senses about its axis is arranged to cause movement of the container in different directions.

25. Apparatus as claimed in any of Claims 22, 23, or 24 in which the rotatable member cooperates with part of the apparatus arranged to be moved by the rotatable member to resist relative axial movement of the rotating member and the part that is so cooperated with.

26. Apparatus as claimed in any of Claims 22 to 25 including two rotatable driven members.

27. Apparatus as claimed in Claim 26 in which the members have any of the features of the rotatable driven member as herein described.

28. Apparatus as claimed in Claim 26 or 27 in which a common drive means is provided for the driven members.

29. Apparatus as claimed in any preceding claim in which the container is arranged to be open at the top.

30. Apparatus as claimed in any preceding claim in which the container is arranged to be emptied by being upturned.

31. Apparatus as claimed in any preceding claim in which the container is arranged to be emptied at a different location to the region where the matter in the container is arranged to be sterilised.

32. Apparatus as claimed in Claim 30 or 31 in which the container is arranged to be upturned by apparatus that has any one of the features as hereinbefore described.

33. Apparatus as claimed in any preceding claim in which the apparatus includes pressurising means arranged to pressurise the container during at least part of the sterilisation.

34. Apparatus as claimed in any preceding claim in which the volume of the container is greater than 10m3.

35. Apparatus as claimed in Claim 34 in which the volume is in the region of 20m3.

36. Sterilising apparatus substantially as herein described with reference to, and as shown in any of Figures 1 to 6 of the accompanying drawings.

37. A method of sterilising matter comprising locating the matter in a container and supplying steam to the container and causing movement of the container whilst steam is located in the container.

38. A method as claimed in Claim 37 comprising agitating the material in the container during sterilisation.

39. A method as claimed in Claim 37 or 38 comprising moving the container to and fro during sterilisation.

40. A method as claimed in Claim 39 comprising moving the container about an axis.

41. A method as claimed in any of Claims 37 to 40 comprising pressurising the container during sterilisation.

42. A method of sterilising matter substantially as herein described with reference to, and as shown in any of Figures 1 to 6 of the accompanying drawings.

43. A sterilisation plant including a first region where matter to be sterilised is located in a container, transportation means arranged to move the matter from the first region to a second region where the matter within the container can be sterilised and transportation means arranged to move the container to a third location where matter in the container that has been sterilised can be emptied therefrom.

44. A sterilisation plant in which the sterilising apparatus at the second region is as herein described.

45. A sterilisation plant as claimed in Claim 43 or 44 in which the method of sterilising the matter may be as herein described.

46. A sterilisation plant as claimed in any of Claims 43 to 45 in which the method includes two second regions in which matter can be sterilised.

47. A sterilisation plant substantially as herein described with reference to, and as shown in Figures 5 or 6 of the accompanying drawings.