Chemical apparatus and process disinfecting – deodorizing – preser – Process disinfecting – preserving – deodorizing – or sterilizing
Patent
1996-03-18
1998-09-01
Thornton, Krisanne
Chemical apparatus and process disinfecting, deodorizing, preser
Process disinfecting, preserving, deodorizing, or sterilizing
241606, 241DIG38, 366144, 366302, 422 28, 422 38, 422307, 422309, A61L 200
Patent
active
058007768
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to a method and a machine for sterilizing or disinfecting waste, particularly infected hospital waste, based on the known method of the thermal decomposition of the proteins constituting living cells.
In the known methods of heat-sterilization or disinfection, the difficulty of heating the material to be treated involves cycles of long duration, caused by the low coefficient of transfer of heat from the exterior to the interior of the waste. In these methods, heat is transferred to the ready-ground waste or by blowing in saturated steam at a pressure of approximately 0.5 Pascal, if autoclave systems are used, or by blowing in hot air or steam superheated to a temperature of approximately 180.degree. C. in dry systems, or even by heating through the walls.
Although systems exist which use micro-wave radiation to make the heat penetrate the interior of the waste, the plants using this principle can only attain the temperatures necessary for sterilization with difficulty since the need for the presence of water for transforming the microwaves into heat energy prevents the temperature being increased to above the boiling temperature of the water.
SUMMARY OF THE INVENTION
The object of the present invention is to provide an improved method and apparatus which enable waste to be sterilized without contamination risks and which, following the treatment, give rise to an easily disposable sterilized material.
A further object of the invention is to provide a method and an apparatus suitable to be used for the disposal of infected waste, in the hospital environment, even on a small scale, relatively economically and suitable for automation.
In order to attain these objects, the method which is the subject of the invention is characterized in that it comprises the operation of grinding and/or comminuting the waste under a shear stress and for an amount of time such that a quantity of heat sufficient to reach and maintain the sterilization or disinfection temperature in the mass of waste is generated by friction.
The distinctiveness of the method according to the invention is that the heat energy necessary for reaching and maintaining the temperature is generated by impact as well as by both intra- and extra-molecular friction, making use of the kinetic energy supplied to the system by a bladed shaft rotating at high speed inside a housing, preferably provided with fixed striker plates. This system enables the programmed temperature to be reached particularly quickly and the latter is then checked, preferably by the dosing and evaporation of water. In addition to the sterilization (or disinfection) treatment, the method also enables the waste to be comminuted, the plastics material present in, or suitably added to, the waste to be melted, and the treated material finally to be granulated.
The apparatus which is the subject of the invention is characterized in that it comprises a housing suitable for containing waste, a rotor inside the housing provided with vanes or blades suitable for grinding and/or comminuting the waste, and drive means which can rotate the rotor at a speed such that a temperature sufficient for the sterilization or disinfection of the waste is generated by friction and maintained inside this housing, and water intake means in the housing.
The value of the temperature in the bulk of waste, inside the housing, is determined according to whether the intention is simply disinfection and thus simply destroying the pathogenic micro-organisms, or is complete sterilization and thus complete removal of the living sporogenous or asporogenous micro-organisms.
After having reached in a few minutes the programmed temperature at which the plastics parts present or added, as it will be stated hereinafter, soften ,such temperature is maintained for approximately half an hour, dissipating the heat derived from energetic agitation by means of the injection of water. The dosing of the water is controlled by a temperature regulator; this dosing also enable
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Morgantini Gianpiero
Pellegrin Roberto
S.T.R.A.P. SrL
Thornton Krisanne
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