AN AUTOCLAVE

Abstract: There is provided an autoclave (10) having a door (12) hingedly connected (at 13) to a vessel portion (11). A catch member (34) is provided for locking the door and the vessel portion, the catch member being biassed by spring (38) towards a locking position. The catch member is movable, preferably using a solenoid (36), out of said locking position.

Description: AN AUTOCLAVE The present invention relates to autoclaves. According to the present invention there is provided an autoclave comprising a vessel portion, a closure member hingedly connected to the vessel portion, sealing means adapted to form a seal between the vessel portion and the closure member when the autoclave is in a closed condition, and locking means for locking the vessel portion and the closure member together when the autoclave is in said closed condition, said lock means incorporating a catch member biassed towards a locking position and said closure member having catch means for cooperating with said catch member to constitute the locking action, and said catch member being movable against said biasing out of said locking position. Preferably there is an intermediate condition between the closed position and an open condition, said intermediate condition being constituted by partial opening of the closure member. In one preferred embodiment the full opening of the autoclave is prevented by a projection on the closure member engaging a lug on the catch member when the catch member is moved out of its locking position. It is a preferred feature that a solenoid is activated to move the catch member out of the locking position, past an open position and into said intermediate position where the lug engages the projection. Conveniently the sealing means comprises an endless sealing ring located in the closure member for cooperation with a sealing surface on the vessel portion. Normally, this sealing surface comprises an outwardly turned flange. In preferred arrangements the catch member is hingedly connected to the vessel portion and has an angled undercut remote from the hinge and the catch means on the lid comprises a strike plate. With one embodiment the catch member is received in a radially extending slot in the periphery of the closure member opposite its hinge connection to the vessel portion and the strike plate catch means is located at the radially inner edge of the slot, the projection extending into the open end of the slot to prevent the closure member from hinging open beyond said intermediate condition. Preferably the catch member has a lever arm projecting from the area of its hinge connection to the vessel portion, which lever arm is acted upon by the biasing and by the solenoid. Conveniently the biasing is in the form of a return spring. Ideally there is a break link in the action of the catch member and the solenoid. This may comprise a spring holding the end of the solenoid in contact with the lever arm to prevent opening of the closure member when the autoclave is pressurised. An embodiment of the invention will now be described in more detail. Reference is made to the accompanying drawings in which: Figure 1 is a plan view of an autoclave according to the present invention in a closed condition, Figure 2 is a front view of the autoclave shown in figure 1, Figure 3 is a side view of the autoclave shown in figure 1, Figure 4 is a perspective view of the autoclave from the rear, one side and above, Figure 5 is a front view of a closure member of the autoclave, Figure 6 is a perspective view of a lever member of the autoclave, Figure 7 is a partial cross-section on line 8-8 of figure 2, Figure 8 is a partial cross-section similar to figure 7 with the autoclave in a fully open condition, Figure 9 is a partial cross-section similar to figure 7 with the autoclave in a frozen position during opening, Figure 10 is a partial cross-section similar to figure 7 with the autoclave in an intermediate condition, and Figures 11 to 16 are views of a further embodiment which views correspond to those shown in figures 1 to 3, 6, 9 and 10. In the drawings there is shown an autoclave 10 comprising a vessel portion 11 and a closure member in the form of a door 12 which is hingedly connected at 13 to the vessel portion by way of a mounting assembly 17. Inside the door 12 is located an endless sealing ring 14 which is made of a resilient material such as rubber or synthetic rubber and which is of a generally v-shaped cross-section, a metal plate 15 being located in the radially inward facing open V of the sealing ring 14. The operation of such a sealing arrangement is well known and will not, therefore, be discussed in detail except to say that a seal is formed between the door 12 and an outwardly turned flange 16 formed on the vessel portion 11. Opposite the hinge connection 13 of the door 12 is a slot 20 which extends radially inwards a short distance. At the radially innermost edge of the slot 20 a metal strike plate 21 is secured to the door 12. From one edge of the slot 20, a projection 22 extends into the slot 20 towards the opposite edge of the slot. The door 12 is also provided with reinforcing ribs 23 and conventional autoclave entry ports 24 for enabling access of pressure and temperature measuring equipment. On the opposite side to the hinge connection 13, a catch member 30 is hingedly connected at 31 to the vessel portion 11 by way of a second mounting assembly 32. The catch member 30 is generally L-shaped having a main body 33 and a substantially peφendicular lever arm 34 extending therefrom in the location of the hinge connection 31 to the second "* mounting assembly 32. Attached to a bracket 35 extending sideways from the vessel portion 1 1 is a solenoid 36 which has its armature attached to a moving element 37 which extends freely through a hole 45 in the lever arm 34 of the 0 catch member 30. Between the solenoid 36 and the lever arm 34 is a spring 38 which acts to urge the lever arm 34 away from the solenoid 36 into a locking position. A further spring 39 is attached to the moving element 37 at 40 and presses against the other, front side of the lever arm 34 to constitute a 5 break link mechanism. The main body 33 of the catch member 30 has a hook portion 41 remote from the hinge connection 31 , which hook portion 41 comprises .an .angled undercut 42. The hook portion 41 is dimensioned so as to pass through the slot 20 in the door 12 between the projection 22 and the strike 0 plate 21. The hook portion 41 also has a lug 43 for engagement with the projection 22 to prevent opening of the door 12 in certain circumstances which will be described later. Forward of the undercut 42 is a surface 44 which is angled relative to a lengthwise axis of the autoclave 10. 5 Operation of the autoclave 10 will now be described making reference primarily to figures 7 to 10. Starting from the open condition as shown in figure 8, objects for sterilisation have already been put in the vessel portion 11 ready for the door 12 to be closed and the inside of the autoclave 0 to be subjected to appropriate conditions of temperatures and pressure using heating and control apparatus which has not been described. In figure 8 the door 12 is shown just prior to being closed. 5 To close the door 12 it is simply pushed towards the vessel portion 11. The hook portion 41 of the catch member 30 passes through the slot 20, the lug 43 passing the projection 22 of the door 12. The edge of the -> door 12 engages the angled surface 44 of the catch member causing it to deflect outwardly against the inward biasing of the spring 38. The sealing ring 14 then engages the flange 16 and deforms slightly to allow the undercut 42 to pass the front edge of the strike plate 21 and snap back in front of the 0 strike plate 21 under the influence of the spring 38. In this position a seal is created between the vessel portion 1 1 and the door 12 without much closing force being necessary. This closed and locked position is shown in figure 7. The autoclave 10 can then undergo a ς temperature and pressure cycle. When it is desired to open the door, after the autoclave 10 has been allowed to cool and reduce its pressure, there may still be some residual pressure inside. The solenoid 36 is actuated causing the moving element 37 to move rearwardly. This causes the catch member 30 to rotate about the 0 hinge connection 31 thereby resulting in a rapid outward motion of the hook portion 41. The force of the solenoid is sufficient to overcome the angled strike plate 21 /undercut 42 interengagement by urging the door 12 slightly rearwardly thus compressing the sealing element slightly in the axial 5 direction. As the hook portion 41 moves radially outwardly the residual pressure in the autoclave and the resilience of the sealing ring 14 causes the lid to open slightly, see figure 9. This vents the residual pressure as the 0 mechanism moves towards the figure 10 position. In the figure 10 position the hook portion has moved to its extreme outward position caused by the solenoid and the door 12 has continued to open. The lug 43 and projection 22 5 have, however, engaged to prevent further opening of the door 12 whilst the residual pressure may still be present and be potentially harmful. The solenoid 36 is then de-actuated, allowing the hook portion -* 41 to return inwards under the pressure of the spring 38. The hook 41 is now behind the radially outer edge of the strike plate and the lug 43 and projection 22 are no longer in engagement. Now the door 12 can be fully opened again, the situation in figure 10 having been obtained. 0 The further spring 39 constituting the break link mechanism is a safety feature just in case the solenoid 36 is actuated whilst the autoclave is still pressurised. The strength of the spring 39 is a matter of design choice. Essentially the solenoid 36 will only move the hook portion radially outwards 5 into an unlocked position if the restraining force applied to the catch member 30 is less than the force exerted by the spring 39. The restraining force of the catch member 30 is generated by the interaction of forces at the undercut 42/strike plate 21 interface caused by the pressure within the autoclave 10 and also by the resilience of the sealing ring 0 14. The angles of the undercut 42 and strike plate 21 have been chosen in the illustrated embodiment to lock at low applied pressure. In other words, if there is a high pressure in the autoclave then the force required to overcome the undercut/strike plate interconnection will be greater than the strength of 5 the spring 39 and so the solenoid will be activated with no movement of the catch member 30 occuring because the spring 39 will simply compress against the lever arm 34. If there is a low enough pressure in the autoclave such as the residual pressure mentioned above then the force required to 0 overcome the undercut/strike plate interconnection will be less than the strength of the spring 39 and so activation of the solenoid will cause movement of the catch member. 5 It will also be appreciated that the precise form of the construction is a matter of design choice and other biasing/movement mechanisms could be used. An example of an alternative design is shown in figures 1 1 to 16. In the alternative arrangement many features are the same as those shown in figures 1 to 10. The areas of change are springs 38, 39, moving element 37 and the projection/lug combination 22, 43. The moving element 37 of the alternative arrangement shown does not extend forward of the lever arm 34 of the catch member 30. Spring 39 is replaced with a generally C-shaped spring 39a having one end engaged in a hole in the moving element 37 behind the lever arm 34 and its other end braced against the forward face of the lever arm. The spring 38 is replaced with a generally V-shaped spring 38a acting between the solenoid 36 and the back face of the lever arm 34 and having both ends extending around the moving element 37. Both springs 38a and 39a act in the same manner and direction as springs 38 and 39 of the first embodiment. Projection 22 has been replaced with a catch plate 22a which extends across the slot 20 of the door 12. The cooperating lug 43 is replaced with an undercut recess 43a which engages the plate 22a when in the figure 16 configuration in a similar manner to the projection/lug combination 22/43 in figure 10. Other sealing arrangements could also be envisaged and also a plurality of catching mechanisms could be provided. Also, other fail safe mechanisms could be used to prevent opening of the autoclave whilst under pressure. Although the closure member above has been termed a door because the axis of the autoclave is generally horizontal it will be appreciated that the invention is equally applicable to vertical autoclaves in which the door is in the form of a lid hingedly connected to the vessel portion. In addition, the solenoid could be replaced with any other suitable means for effecting movement of the catch member.

Claims: CLAIMS 1. An autoclave comprising a vessel portion, a closure member hingedly connected to the vessel portion, sealing means adapted to form a seal between the vessel portion and the closure member when the autoclave is in a closed condition, and locking means for locking the vessel 0 portion and the closure member together when the autoclave is in said closed condition, said lock means incorporating a catch member biassed towards a locking position and said closure member having catch means for cooperating with said catch member to constitute the locking action, ς and said catch member being movable against said biasing out of said locking position. 2. An autoclave as claimed in claim 1 wherein there is an intermediate condition between the closed position and an open condition, said 0 intermediate condition being constituted by partial opening of the closure member. 3. An autoclave as claimed in claim 2 wherein the full opening of the 5 autoclave is prevented by a projection on the closure member engaging a lug on the catch member when the catch member is moved out of its locking position. 0 4. An autoclave as claimed in claim 2 wherein the full opening of the autoclave is prevented by a plate on the closure member engaging an undercut recess on the catch member when the catch member is moved out of its locking position. 5 5. An autoclave as claimed in any one of claims 1 to 4 wherein that a solenoid is activated to move the catch member out of the locking position, past an open position and into said intermediate position. 6. An autoclave as claimed in any one of claims 1 to 5 wherein the sealing means comprises an endless sealing ring located in the closure member for cooperation with a sealing surface on the vessel portion. 7. An autoclave as claimed in claim 6 wherein the this sealing surface comprises an outwardly turned flange. 8. An autoclave as claimed in any one of claims 1 to 7 wherein the catch member is hingedly connected to the vessel portion and has an angled undercut remote from the hinge and the catch means on the lid comprises a strike plate. 9. An autoclave as claimed in claim 8 wherein the catch member is received in a radially extending slot in the periphery of the closure member opposite its hinge connection to the vessel portion and the strike plate catch means is located at the radially inner edge of the slot, the projection extending into the open end of the slot to prevent the closure member from hinging open beyond said intermediate condition. 10. An autoclave as claimed in claim 9 wherein the catch member has a lever arm projecting from the area of its hinge connection to the vessel portion, which lever arm is acted upon by the biasing and by the solenoid. ■ l O- 1 1. An autoclave as claimed in claim 10 wherein Conveniently the biasing is in the form of a return spring. 12. An autoclave as claimed in any one of claims 9 to 1 1 wherein there is a break link in the action of the catch member and the solenoid. 13. An autoclave as claimed in claim 12 wherein the break link comprises a spring holding the end of the solenoid in contact with the lever arm to prevent opening of the closure member when the autoclave is pressurised.

Inventors: THOBURN ROBERT JAMES, THOBURN, ROBERT, JAMES
Applicants: MEDIN LTD, THOBURN ROBERT JAMES, MEDIN LIMITED, THOBURN, ROBERT, JAMES
Application year: 1997
Main classification: F16J13
IPC codes: F16J13