GB2142826A - Autoclaves - Google Patents

Abstract

An autoclave having an opening closeable with a door by way of a resilient seal is provided with a plurality of claws 30 adjacent the opening. Each claw is adapted to releasably engage abutment surfaces on the door only with the autoclave under reduced pressure of atmosphere with the seal under compression. The door is thus safely retained in the closed position with the seal compressed to prevent leakage. <IMAGE>

Description

SPECIFICATION Improvement in closures This invention relates to closures for autoclaves and the like and is particularly though not exclusively directed to closures for steam autoclaves intended for sterilisation.

The use of autoclaves for steam sterilisation is well known and a variety of types are in common use. Such known autoclaves are characterised by a chamber capable of withstanding applied steam pressure and having an opening through which articles to be sterilised can be fed for stacking. The opening is provided with a suitable closure which must be designed also to withstand chamber steam pressure and in particular to prevent the seepage of steam at the chamber opening/closure interface.

The problem of seepage is particularly acute with relatively large autoclaves having comparatively larger openings. It has been proposed to effectively seal such large autoclaves by providing the opening/closure interface with a resilient seal which is capable of being placed under compression by initially evacuating the chamber and which can subsequently be retained under compression by suitable retaining means during pressure sterilisation.

One example of such retaining means comprise a plurality of bolts which are captive on the closure and which are adapted to engage corresponding openings in the chamber wall when and only when the resilient seal is under compression. However, with relatively large openings, a considerable number of such bolts are required to effectively seal the autoclave; both the cost of providing and the difficulty of operating simultaneously such a plurality of bolts is considerable and it is one object of the present invention to ameliorate these disadvantages.

The present invention according to its broadest aspect provides an autoclave or like chamber intended to operate under positive pressure, the autoclave having a loading and unloading opening closeable with a door by way of a resilient seal, a plurality of claws being provided on the autoclave adjacent the opening each claw being adapted to releasably engage abutment surfaces on the door and adjacent the opening only with the autoclave under reduced pressure of atmosphere with the seal under compression and to retain the door in position with the seal compressed.

By the use of the claws in accordance with the invention positive sealing with the seal compressed can be maintained at the door/ opening interface when the autoclave is pressurised. Moreover, since the autoclave internal pressure must be reduced to below atmosphere to enable to claws to disengage and the door to be opened, the retaining arrangement is inherently safe as well as being simple to operate.

In one embodiment the claws may be pivotally mounted on the autoclave adjacent the opening to enable them to be moved into and out of abutment with the door outer surface; to simplify operation all the claws or groups of claws may be mechanically coupled to operate simultaneously for example by way of an operating bar or rod.

In a preferred embodiment of the invention however, the claws are arranged to move into and out of engagement with the autoclave chamber and door outer surface along a path substantially parallel to the periphery of the autoclave opening. In this case the radially outer edge region of the door is provided with cut-away portions which accommodate the claws in the unlocked position from which the claws can move into engagement with the door outer surface adjacent the cut-away portions.

Such a preferred arrangement displays particular advantages in the case of an autoclave or chamber having a circular opening for loading and unloading and which is closed by a circular door. In this case all the claws disposed about the door periphery conveniently are coupled together for example by an annular ring which can be turned by the operator for simultaneous locking in one simple operation.

Suitably the claws are held on the autoclave by way of bearings retained for movement within a provided groove adjacent the autoclave opening.

Any number of claws may be provided, the number necessary to provide effective sealing, depending upon the peripheral length of the opening and the rigidity of the door closure.

An embodiment of the invention will now be particularly described by way of example with refence to the accompanying drawings in which Figure 1 is an axial section of the loading end of an autoclave provided with claws according to the present invention and Figure 2 is a schematic perspective view of the door closure of the autoclave shown in Fig. 1.

Referring to the drawings the autoclave indicated generally at 2 comprises a substantially cylindrical chamber 4 which is defined by an outer metal wall 6 and which has an opening 8 releasably closed by a door 10. As shown more particularly in Fig. 2 a window indicated generally at 11 is provided at the door centre to enable the contents of the autoclave to be kept under observation. The door is supported for movement by a cranked arm 1 2 pivotally secured respectively to bracket 14 providedon chamber wall 6 and a block 1 6 provided on the door outer surface.

Cranked arm 1 2 enables the door when opened to move well clear of the opening 8 in chamber 4 to facilitate loading and unloading.

Secured to and surrounding the outer edge of door 10 is a castellated annular member 1 8 provided at its rearwardly facing edge with a circumferentially continuous groove effective to retain a resilient sealing ring or gasket 20.

Ring 20 which is of any suitable material such as silicone rubber capable to providing a seaiing function at the operating temperature and pressure of the autoclave is adapted to stand proud of the surface of member 18 with the door open.

Secured to the outer edge of the autoclave chamber wall 6 is acircumferentially continuous metal annulus 22 positioned with the door10 firmly closed to substantially abut the adjacent surface of member 18 and to maintain the sealing ring 20 under compression.

An annular ring 24 also secured to the chamber outer wall defines with the annulus 22 a circumferentially continuous groove 26.

Groove 26 is effective to accommodate the outer cage of a ball race 28 which is dimensioned to move freely along the groove but which is retained captive in the manner herein described.

Attached to the inner cage of ball race 28 is a stud 29 supporting a claw 30 comprising a central yoke having a short limb at each end.

The limbs have opposed end faces accurately machined to slideably abut the outer surfaces respectively of the member 18 and annulus 22 with and only with the door 10 firmly closed and ring 20 maintained under optimum compression. As herein described optimum compression occurs with the adjacent surfaces of member 18 and annulus 22 firmly in abutment; in this position claw 30 together with the similar claws spaced round the door periphery will maintain the autoclave firmly sealed when under positive internal pressure.

As shown more precisely in Fig. 2, an actuating ring 32 secured to the outer surface of each claw 30 enables all the claws to be simultaneously moved into and out of abutment with the member 18 and annulus 22.

Again as shown more precisely in Fig. 2, the castellated member 18 secured to the door periphery has cut-away portions 34 effective to permit the spaced array of claws 30 to clear the door during opening and closing operations. Handle 38 attached to the operating ring 32 enables the claws to be simultaneously moved with a degree of mechanical advantage.

In use and with the door 10 moved to close off the chamber 4, after loading, the chamber is evacuated to enable pressure of atmosphere to force seal the door, bring the adjacent surfaces of members 18 and 22 into abutment and compress the ring 20. With door 10 effectively closed, and claws 30 accommodated in cut-away portions 34 of member 18, handle 38 as shown in Fig. 2 is moved clockwise to move the claws to overlie the door outer surface. This movement positions the claws to retain the door against opening.

With the door so retained the chamber can be pressurised, for example with steam when the reverse operation for unloading may be effected.

It will be appreciated that while the closure of the invention has been described with reference to an autoclave of circular section, it is equally applicable to any chamber whether circular or not and whether intended to be pressurised or not. It will equally be appreciated that while in the embodiment described all the claws are simultaneously operated, groups of claws may be individually or collectively operated by suitable manual or automatic means.

Claims (11)

1. An autoclave or like chamber intended to operate under positive pressure, the autoclave having a loading and unloading opening closeable with a door by way of a resilient seal, a plurality of claws being provided on the autoclave adjacent the opening each claw being adapted to releasably engage abutment surfaces on the door and adjacent the opening only with the autoclave under reduced pressure of atmosphere with the seal under compression and to retain the door in position with the seal compressed.

2. An autoclave as claimed in claim 1, wherein the claws are pivotally mounted on the autoclave adjacent the opening to enable them to be moved into and out of abutment with the door outer surface.

3. An autoclave as claimed in claim 2, wherein all the claws or groups of claws are mechanicaly coupled to operate simultaneously.

4. An autoclave as claimed in any preceeding claim, wherein the claws or groups of claws are coupled by way of an operating bar or rod.

5. An autoclave as claimed in claim 1, wherein the claws are arranged to move into and out of engagement with the autoclave chamber and door outer surface along a path substantially parallel to the periphery of the autoclave opening.

6. An autoclave as claimed in claim 5, wherein the radially outer edge region of the door is provided with cut-away portions which accommodate the claws in the unlocked position from which the claws can move into engagement with the door outer surface adjacent the cut-away portions.

7. An autoclave as claimed in claim 5 or claim 6 wherein, all the claws disposed about the door periphery conveniently are coupled together by means which can be turned by the operator for simultaneous locking.

8. An autoclave as claimed in claim 7 wherein, the claws are coupled by an annular ring.

9. An autoclave as claimed in any of claims 5 to 8 wherein the claws are held on the autoclave by way of bearings retained for movement within a groove provided adjacent the autoclave opening.

10. An autoclave or like chamber substantially as herein described with reference to the accompanying drawings.

11. An autoclave as shown in and adopted to operate substantially as herein described with reference to the accompanying drawings.