Chemical apparatus and process disinfecting – deodorizing – preser – Process disinfecting – preserving – deodorizing – or sterilizing – Using direct contact steam to disinfect or sterilize
Patent
1988-01-22
1991-05-28
Lacey, David L.
Chemical apparatus and process disinfecting, deodorizing, preser
Process disinfecting, preserving, deodorizing, or sterilizing
Using direct contact steam to disinfect or sterilize
422 33, 422300, 220203, 220204, 220366, A61L 200
Patent
active
050193457
DESCRIPTION:
BRIEF SUMMARY
Sterilizing containers are used to accommodate clinical sterile material which must be subjected to a steam sterilization. Said sterilization takes place in sterilizers which operate either by the gravitation method (flow method) or in modern equipment increasingly by a vacuum method in which firstly one or more vacuum phases are provided to extract the air from the container, whereafter the container interior is exposed to a steam atmosphere under elevated pressure and elevated temperature, the sterilizing material thereby being subjected to a sterilization. It is advantageous to drain condensate forming so that the material is available as dry as possible after the sterilization. After the steam sterilization time the container is subjected to a further vacuum treatment to withdraw the sterilization steam with any remaining condensate from the container.
To permit the medium exchange the sterilizing containers are either equipped with filters allowing a medium exchange but preventing recontamination or valves are disposed in the container wall which close after the pressure exchange is completed. As influx or vacuum valves check valves according to DE 217,551 or a double valve according to DE 1,217,550 are frequently used. As condensate draining valve bi-metal valves have established themselves which have the advantage over pure check valves that an opening of the valve for draining the condensate can take place throughout the entire sterilizing stage.
A valve which can carry out all these functions is known from U.S. Pat. No. 4,228,914. In this case the gas chamber acting on the valve body is filled with steam during the steam influx phase and at the end of the steam influx phase, i.e. at the start of the sterilization time, the influx opening to the gas chamber is sealed via a shrink hose so that on the subsequent pressure reduction expansion of the gas chamber can effect closure of the valve. This construction requires that after each sterilizing operation the shrink hose must be replaced to ensure the sealing function. The sealing function cannot be effected properly if the shrink hose does not establish a reliable seal. If a leakage flow takes place at the influx opening the seal is jeopardized because the pressure difference necessary for the closure pressure cannot form.
The invention overcomes the problem of providing an operationally safe valve system which operates reliably automatically without addition and setting of parts and can be used in a variety of ways.
Due to the fact that the gas volume remains permanently in the chamber and need not be replenished on each sterilizing operation as in the prior art a reliable and leak-flow-free seal can be achieved in simple manner, and said gas volume can be introduced under a defined pressure at predetermined temperature, in particular under atmospheric pressure, thereby ensuring reliable operation. Conveniently, the differential pressure valve function is subjected to a spring bias, the valve opening or closing operation thereby being displaced somewhat with respect to the atmospheric line. This is however admissible and desirable and the temperature-induced pressure differences within the gas chamber can be compensated adequately as regards the desired function.
The particular difference of the invention compared with conventional check valves resides in that in this case the control force is not the pressure difference acting on the valve disc but a force resulting from the compression or elongation of a pressure pickup (roll diaphragms, diaphragms, concertina hose, corrugated tube, pressure cylinder, barometer cam, etc.) which effects the valve stroke via control rods, control cams, levers, or alternatively (preferably) directly. The decisive part for the opening and closure condition of the valve is therefore played by the pressure present in the sterilizing chamber and not the presence (absence) of a pressure difference at the valve itself. The control force generated by the pressure pickup can be further intensified by supplementing (replacin
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patent: 4748003 (1988-05-01), Riley
patent: 4770851 (1988-09-01), Joslyn
patent: 4948566 (1990-08-01), Gabele et al.
Lacey David L.
Snay Jeffrey R.
Wagner GmbH
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