Autoclave With Heat Chamber Having Sliding Peripheral Wall
The present invention relates to pressure vessels, and more particularly to a pressure vessel having a slidably removable, cylindrical lateral wall and fixed end walls. The end walls are mutually connected by rods passing through the interior of the closed vessel. The rods both reinforce the endwalls against blowout and also conduct fluids such as steam for treating objects placed inside the pressure vessel. However, for ovens such as autoclave, which must be loaded with objects which are treated with steam and subsequently removed, it is not feasible to employ construction appropriate for gas storage. A door must be provided for inserting and retrieving treated objects. The door is frequently located at one end of a cylindrical body, so that a lateral wall may comprise an uninterrupted cylinder. The end wall must be reinforced against both buckling and against expulsion from the cylinder.
An example of this situation is shown in U.S. Pat. No. 5,002,196, issued to John Bassili on Mar. 26, 1991. A retaining member is placed over an end of the pressure vessel, and is secured to the exterior of the cylindrical body. The retaining member must be carefully and securely fixed to the cylindrical body. By contrast, the present invention includes rods disposed inside the pressure vessel which span both ends, and firmly connect one to the other. This construction assures that each end will counteract pressure operating on the other end. Therefore, no complicating apparatus must be provided for securing each end to the cylindrical body. Pressure vessels operating at pressures greater than surrounding ambient pressure are subject to bursting, and must be designed to resist bursting. It is customary to exploit certain properties of geometric solids to minimize stoutness of construction when providing requisite strength. For example, containers of compressed gas are frequently cylindrical along their length, with domed ends. This configuration is easily fabricated, and presents few problems when storing compressed gasses.
A pressure vessel utilizing mutually connected end walls is shown in U.S. Pat. No. 4,082,510, issued to Dragomir Jovanovic on Apr. 4, 1978. However, Jovanovic reverses the concept of the present invention. Jovanovic fixes the cylindrical lateral wall to the base of the pressure vessel and slides the ends longitudinally between open and closed positions. By contrast, in the present invention, the ends are fixed to the base and the cylindrical body is moved relative to the base. This affords a significant advantage over Jovanovic. That is, rods connecting the ends are fixed to the base and may be exploited to conduct fluids into and out of the chamber. Therefore, the novel construction enables steam to be delivered into the chamber when sealed, and atmospheric gasses to be evacuated from the sealed chamber when desired. These functions cannot be performed by the device of Jovanovic without penetrating the cylindrical body. Also, in the present invention, the cylindrical body is fully removable from the pressure vessel. By contrast, in the device of Jovanovic, the cylindrical body and end wall assembly are captively joined to one another. Even further, it becomes practical to mount controls and other ancillary devices in one or both end walls of the novel pressure vessel. In a further option, the lateral wall of the chamber is frustoconical rather than cylindrical. This configuration does not contravene structural advantages of a cylindrical lateral wall, since at each cross section taken perpendicularly with respect to its length, the lateral wall remains circular. In this embodiment, sealing is enhanced since downward pressure against the lateral wall compresses O-rings or corresponding gaskets or seals for sealing the chamber. This embodiment further expedites removal of the lateral wall should a seal distort, thereby causing the lateral wall to bind. Accordingly, it is an object of the invention to provide an autoclave which has a working chamber wherein opposed walls are mutually connected, so that internal pressure pressing outwardly on each wall is counteracted by an opposed wall.