Scruton M W
Sterilization R & D Unit, PHLS Centre for Microbiology & Research, Salisbury, Wiltshire, UK.
J Hosp Infect. 1989 Oct;14(3):249-62. doi: 10.1016/0195-6701(89)90042-x.
The effect of residual air on the local temperature within an autoclave has often been calculated solely from the known relationship between the pressure and temperature of steam in equilibrium with water. A system of directly measuring air is described which, together with temperature measurements, indicates that large volumes of air trapped in an autoclave load are not necessarily associated with reduced temperatures, although their presence will considerably prolong the heat-up period. It is confirmed that a restricted flow of steam into an autoclave chamber, with reliance on a 'balanced pressure' thermostatic trap as a condensate and air outlet, will not remove air efficiently, even from an empty chamber. Long heating times observed when polypropylene containers are used for laboratory discard material are probably due to retention in the container of large volumes of air. When an efficient air displacement system is employed heat-up times are considerably reduced; the conductivity of the container material being less important than the penetration of steam to its contents.
以往通常仅根据与水处于平衡状态的蒸汽的压力和温度之间的已知关系来计算高压灭菌器内残余空气对局部温度的影响。本文描述了一种直接测量空气的系统，该系统与温度测量结果表明，尽管高压灭菌器负载中截留的大量空气会显著延长升温时间，但这些空气的存在不一定与温度降低相关。可以确定的是，依靠“平衡压力”恒温疏水阀作为冷凝水和空气出口，蒸汽进入高压灭菌器腔室的流量受限，即使在腔室为空的情况下，也无法有效排出空气。当使用聚丙烯容器来盛放实验室废弃物时，观察到加热时间较长，这可能是由于容器中滞留了大量空气。当采用高效的空气置换系统时，升温时间会大幅缩短；容器材料的导热性不如蒸汽渗透到其内容物重要。
