Patent GB-889044-A (GB)
Title: Autoclave or steriliser for hospitals
Inventor: BACH BRIAN
IPC: A61L2/07
Filed: 1959-05-01
Abstract: 889,044. Sterilizers. SANDERSON & CO. (TEXTILE ENGINEERS) Ltd. July 29, 1960 [May 1, 1959], No. 14880/59. Class 81 (1). A sterilizer comprising a base 10 and a bell-like casing 11 open at the bottom, means for raising the bell-like casing relatively to the base and for lowering it into sealing engagement with the base, and means for supplying a sterilizing agent to the interior of the belllike casing when the latter is lowered. As shown, the base 10, which contains mechanism for raising and lowering the bell-like casing 11, abuts against and is connected to a casing 12 which carries control means and houses a vacuum pump and other parts referred to below. There is a circular opening 13 in the top of the casing 11, a bowl 14 being mounted within the opening and the bowl having an inlet opening 15 for steam or other sterilizing agent fed through a pipe 16 which is connected to a valve housed within the casing 12 and having one port connected to a vacuum pump and the other port connected to an external steam supply. The bell-like casing 11 is adapted to be raised from a lowered position where its lower open end makes sealing engagement with the opening 13 to a raised position as shown in Figs. 1 and 2, by means of three vertical shafts 17 projecting through the top of the base structure 10, the upper portion of each shaft which is surrounded by telescopic shrouds 27 and tube 28 being screw-threaded and engaged in a nut 18 carried by a lug 19 on the bell-like casing 11. The three shafts 17 are equally spaced around the opening 13, the lower portion of each shaft being mounted in bearings 20, and a spur gear-wheel 21 is secured on the lower end of each shaft, all three gear-wheels 21 engaging with a central driving gear-wheel 22 secured on the output shaft 23 of a slipping coupling 24 driven by a reversible electric motor 25 through worm and worm-wheel gearing 26. The connection and disconnection to the vacuum pump and to the steam supply by the valve and the raising and lowering of the bell-like casing 11 are all arranged to be effected in sequence by means of trip levers, switches and the like, as follows. With the bell-like casing raised, the articles to be sterilized are first placed on a tray 29, above the bowl 14 and a start button 35 on a panel 36 of the easing 12 is depressed so as to start up the motor 25 for lowering the casing 11 and when it is lowered and in full engagement with the sealing means around the opening 13, a trip device causes actuation of the valve to connect the vacuum pump to the bowl 14. When the desired extraction of air has been effected, a barometrically compensated switch causes the valve to connect the steam supply to the bowl 14 until a predetermined temperature is obtained within the casing 11 and then a time switch maintains the steam supply, in conjunction with the temperaturecontrolled means, for a predetermined period of time. At the expiration of this period of time the valve is actuated to exhaust steam from the casing 11 and the vacuum pump is operated to extract all residual moisture. A second time switch controls the vacuum pump and at the expiration of the extraction time the casing is vented to atmosphere through a sterilized filter. When the pressure within the casing 11 reaches atmospheric pressure, the motor 25 is started in reverse direction to raise the belllike casing 11 and the motor is stopped by a trip switch when the casing 11 is raised. Instead of steam being employed as the sterilizing agent an electric heater may be provided to heat air or inert gas which is fed into the sterilizing chamber. There may be two sterilizing units connected to a single control unit so that one sterilizing unit can be in operation whilst the other sterilizing unit is open for discharge and recharging whereby the apparatus can be in continuous operation. Other means to raise and lower the bell-like casing such as hydraulic means may be employed.