GB2333959A

GB2333959A - Autoclave

Info

Publication number: GB2333959A
Application number: GB9900598A
Authority: GB
Inventors: Patrick Brian Clayton
Original assignee: Smiths Group PLC
Current assignee: Smiths Group PLC
Priority date: 1998-02-05
Filing date: 1999-01-13
Publication date: 1999-08-11

Abstract

The autoclave has an annular rubber door seal 20 with outer and inner resilient ribs 21, 22 diverging from one another to form a V-shape, the outer rib 21 being longer than the inner rib. A drain aperture 41 opens just above the inner rib 22 at the lowest point of a flange 4 around the opening of the autoclave chamber 1. A solenoid valve (45, see Fig. 1) prevents passage of condensate through the drain aperture 41 during sterilization, and opens at the end of the sterilization cycle so that water collecting around the seal 20 drains away.

Description

AUTOCLAVES This invention relates to autoclaves.

Autoclaves are used to treat articles with steam at elevated pressure and temperature, such as to effect sterilization. The autoclave chamber is closed by a door through which articles are placed in and removed from the chamber. The door seal usually comprises a flexible gasket bearing on the inside of the door and on the outside of a flange formed around the chamber. There is a tendency for water to collect on this seal and to spill out when the door is opened.

It is an object of the present invention to provide an improved autoclave.

According to one aspect of the present invention there is provided an autoclave having a chamber, a door closing an opening to the chamber and an annular seal extending around the chamber between the chamber and the door, the autoclave having a passage opening just above the lower part of the annular seal, and the autoclave including means operable to prevent flow of liquid through the passage from the chamber during a treatment cycle and to allow liquid collecting above the seal to flow away before opening the door after a treatment cycle.

The seal preferably has an outer and inner resilient rib, the outer rib bearing against an inner surface of the door and the inner rib bearing against an outer surface of the chamber.

The two ribs preferably diverge away from one another, forming a V shape in section, the outer rib being longer than the inner rib. The outer rib at the lower part of the seal preferably projects above the lower edge of the opening of the passage. The seal may be of a rubber. The means operable to prevent flow along the passage preferably includes a solenoid valve. The passage may connect with a reservoir by which liquid is supplied to the chamber before a treatment cycle. The opening of the chamber preferably has a flange extending around the opening, the flange having a forwardly-projecting lip and the seal being located on the lip.

According to another aspect of the present invention there is provided a method of operating an autoclave of the kind having a chamber, a door closing an opening to the chamber, a seal between the door and the chamber, and a passage with a valve, the passage opening just above the lower part of the seal, the method including the steps of performing a treatment cycle with the door closed and with the valve closed, subsequently opening the valve such that pressure in the chamber forces water collected above the seal out along the passage, and then opening the door.

An autoclave and its method of operation, in accordance with the present invention, will now be described, by way of example, with reference to the accompanying drawing, in which: Figure 1 is a simplified sectional side elevation of the autoclave; and Figure 2 is an enlarged sectional side elevation showing the lower part of the door and seal.

The autoclave has a pressure chamber 1, which is closed at its rear end 2 and is open at its forward end 3 where it has an outwardly-extending, radial flange 4 with a forwardlyprojecting annular lip 14. The autoclave includes a conventional heating element 5 controlled by a control unit 6, which also receives inputs from various sensors 7 in the usual way.

During use, the heating element 5 is submerged in water 8 below a rack 9 on which are placed articles 10 to be sterilized.

The open end 3 of the chamber 1 is closed, during a treatment cycle, by a door 11 of conventional construction. The door 11 is hinged about a vertical axis along one side and is locked by a conventional locking mechanism. The rear face 12 of the door 11, when closed, abuts against a seal 20 of annular shape extending around the flange 4 and supported on the inside of the lip 14. The seal 20 is made of a resilient, heat-resistant material, such as rubber, and is V-shape in section with two ribs 21 and 22 extending generally radially inwardly of the seal. The two ribs 21 and 22 diverge outwardly away from one another at an angle of about 90 degrees when uncompressed, the inner rib 22 being shorter than the outer rib 21. The outer rib 21 bears against the inner face 12 of the door 11, whereas the inner rib 22 bears against a parallel, forward face 40 of the flange 4. The flange 4 has a drain aperture 41 extending through it and opening just above the lower part of the annular seal 20 and just above the point where the inner rib 22 of the seal contacts the flange. The aperture 41 slopes down from the forward face 40 of the flange 4 to the rear face 42 and is coupled at the rear with a pipe 43. The pipe 43 and aperture 41 provide a passage extending to a reservoir 44 (which may be the main reservoir by which water is supplied to the chamber) via a solenoid valve 45. The valve 45 is controlled by electrical signals from the control unit 6.

To use the autoclave, the articles 10 to be sterilized are placed on the rack 9 and the door 11 is closed so that it compresses the ribs 21 and 22 of the seal 20 slightly towards one another. The ribs 21 and 22 apply a resilient sealing force to the rear face 12 of the door 11 and to the forward face 40 of the flange 4. The autoclave then admits water from the reservoir 44 to the chamber 1 via the aperture 41 and performs a conventional sterilization treatment cycle. During this, the control unit 6 holds the valve 45 closed so that neither water nor pressure can escape through the drain aperture 41. As pressure rises in the chamber 1, this applies an outward pressure on the two ribs 21 and 22 of the seal 20, so as to increase the sealing pressure. During the sterilization cycle, water lies in the space above the seal 20, between the flange 4 and the inside face 12 of the door 11, as shown in Figure 2. At the end of the sterilization cycle, the control unit 6 opens the valve 45 and hence the passage provided through the aperture 41 and pipe 43 to the reservoir 44. Because the valve 45 is opened when pressure in the chamber 1 is still higher than atmosphere, the elevated pressure will force water in the chamber 1 out through the aperture 41 and into the reservoir 44. The only water remaining on the seal 20 will be that lying between the ribs 21 and 22 up to the level of the drain aperture 41. Because the outer rib 21 extends above the lower edge of the drain aperture 41, the collected water will not leak out when the door 11 is opened.

This arrangement, therefore, avoids the escape of water from the autoclave when the door is opened and thereby reduces the risk of damage or injury caused by contact with leaked water, which could still be hot.

Claims

CLAIMS 1. An autoclave having a chamber, a door closing an opening to the chamber and an annular seal extending around the chamber between the chamber and the door, wherein the autoclave has a passage opening just above the lower part of the annular seal, and wherein the autoclave includes means operable to prevent flow of liquid through the passage from the chamber during a treatment cycle and to allow liquid collecting above the seal to flow away before opening the door after a treatment cycle.
2. An autoclave according to Claim 1, wherein the seal has an outer and inner resilient rib, and wherein the outer rib bears against an inner surface of the door and the inner rib bears against an outer surface of the chamber.
3. An autoclave according to Claim 2, wherein the two ribs diverge away from one another and form a V shape in section.
4. An autoclave according to Claim 2 or 3, wherein the outer rib is longer than the inner rib.
5. An autoclave according to Claim 4, wherein the outer rib at the lower part of the seal projects above the lower edge of the opening of the passage.
6. An autoclave according to any one of the preceding claims, wherein the seal is of a rubber.
7. An autoclave according to any one of the preceding claims, wherein the means operable to prevent flow along the passage includes a solenoid valve.
8. An autoclave according to any one ofthe preceding claims, wherein the passage connects with a reservoir by which liquid is supplied to the chamber before a treatment cycle.
9. An autoclave according to any one of the preceding claims, wherein the opening of the chamber has a flange extending around the opening, wherein the flange has a forwardly-projecting lip, and wherein the seal is located on the lip.
10. An autoclave substantially as hereinbefore described with reference to the accompanying drawings.
11. A method of operating an autoclave of the kind having a chamber, a door closing an opening to the chamber, a seal between the door and the chamber, and a passage with a valve, the passage opening just above the lower part of the seal, wherein the method includes the steps of performing a treatment cycle with the door closed and with the valve closed, subsequently opening the valve such that pressure in the chamber forces water collected above the seal out along the passage, and then opening the door.
12. A method substantially as hereinbefore described with reference to the accompanying drawings.
13. Any novel and inventive feature as hereinbefore described.