Abstract A method of sterilising powders and other fine-grained pulverulent or granular materials employs a gaseous sterilising agent. An upwardly extending closed treatment chamber is partially filled with the material to be sterilised, and the gaseous sterilising agent is admitted to the lower end of the chamber in such manner that the material is flung upwardly into free space at the top of the chamber and substantially allowed to settle again whereafter the process is repeated. Thus, the material is displaced by the sterilising agent and allowed to settle and stand again, or at any rate to complete its settling movement at least to a fluid state, several times. The sterilising agent escapes from an outlet at the top of the chamber, and it is desirably admitted to the latter in a series of pressure shocks of short duration, and in such manner that the material is whirled upwardly by the shock pulses in an ascending peripheral vortex so that the particles are in a state of suspension from which they fall downwards again in an inner vortex axially of the chamber.
A method according to claim 1, wherein the gaseous sterilising agent is admitted in a series of pressure shocks of short duration.
Claim 2
Dependent Claim
61 words
A method according to claim 1, which includes pre-heating the material prior to delivery thereof to the treatment chamber and effecting controlled heating and humidifaction of the gaseous sterilising agent prior to admission thereof to the treatment chamber, said heating and humidification being carried out in a reservoir which contains thermostatically controlled electrical heating means and to which steam is fed.
Claim 3
Independent Claim
159 words
A method of sterilising powders and other fine-grained pulverulent or granular materials comprising partially filling an upwardly extending closed treatment chamber with the material, admitting a gaseous sterilising agent to the lower end of the treatment chamber at a flow rate in excess of that required to fluidize said material and in such manner that the material is whirled upwardly by the gaseous sterilising agent in an ascending peripheral vortex from which the particles of said material fall downwards in an inner vortex axially of the chamber upon termination of the flow of said gaseous sterilising agent, the gaseous sterilising agent being allowed to escape from an outlet at the top of the chamber discontinuing the flow of said gaseous sterilizing agent into said treatment chamber until settling of said material is substantially complete and admitting further gaseous sterilising agent into said treatment chamber to repeat said whirling and falling procedure when settling of the material is substantially complete.
Claim 4
Dependent Claim
26 words
A method according to claim 4, which includes effecting controlled heating and humidification of the gaseous sterilising agent prior to admission thereof to the treatment chamber.
Claim 5
Dependent Claim
19 words
A method according to claim 4, which includes pre-heating the material prior to delivery thereof to the treatment chamber.