送、排风口设置对病房空气途径感染控制的影响

病房送、排风口相对位置与数量对于病房内气流组织和污染物传播有显著影响,为降低呼吸道传染病在病房内的交叉感染率,提出了一种送、排风口设置的优化方案,在每张病床附近均设排风口,通过增加排风口数量、调整送风口位置,使送风与排风路径相对病床为“并联”。以典型的双人病房为例,通过气流组织模拟计算,对优化方案与符合相关导则要求的方案进行了对比。结果显示,优化方案明显改善了室内气流组织,降低了病房内的致病菌浓度。

现行小高炉设计中的几个问题

近几年来,山西省小高炉发展十分迅速,其产量已达到相当水平,在山西冶金中发挥着重要作用。笔者曾多次参加过小高炉的设计和施工,在这期间,发现了一些设计中存在的问题,并在实施的过程中作了相应的研究和修改,本文将根据实践,提出拙见,以供讨论。

Carbon dioxide levels and ventilation for running vehicle

Factors contributing to ventilation quantity of the vehicle are ventilation modes, cabin characteristics and vehicle speeds. CO2 levels were investigated under different speeds and ventilation modes. Four modes were selected： A： vent closed and fan shut, B： vent closed and fan started, C： vent opened and fan shut, D： vent opened and fan started. In vent closed modes, CO2 levels reached several thousands of ppm in few minutes at any speeds. For mode C, CO2 levels exceeded the guideline at low speeds 50 km/h, while it reduced below one at higher speeds 80 km/h. Fan has no significant impact on ventilation during vent closed. The ventilation efficiency in each mode increased with the speed raising. To determine the ventilation rate of running vehicle, the experiment was implemented by using CO2 emitted from driver and passengers as tracer gas. Ventilation rate for the different modes and speeds were calculated.