Pressure-vacuum purge cycle

Claim 1

An improvement in the conditioning phase of a dry goods load sterilization cycle rendering maximum energy and cycle efficiency for use in a steam sterilization process, which conditioning phase removes air from a sterilization chamber and said load therein and humidifies said load, said improvement comprising the steps of: introducing steam into said chamber above the air therein by at least one positive pressure pulse having a predetermined maximum positive pressure of about five pounds per square inch gauge and subsequently venting air therefrom to a predetermined minimum positive pressure of about two pounds per square inch gauge at both of which pressures steam and air will stratify and said steam will thereby displace said vented air in said chamber in a predetermined time; terminating said introduction of steam and substantially simultaneously applying a vacuum of no less than 26 inches of mercury; and terminating said application of vacuum and substantially simultaneously commencing one of at least two predetermined vacuum pulses for a predetermined time.