双层填料中置生物活性炭滤池中试优化研究

采用中置生物活性炭滤池,装填双层填料,对进水浊度约1 NTU左右的沉淀池出水进行去除浊度和有机物中试。结果表明,装填厚3 m粒径准3 mm柱状炭、垫层分别采用厚0.7 m粒径准3～5 mm与厚1.2 m粒径准6～8 mm轻质陶粒,于12 m.h-1滤速、气水体积比为0.2:1的工况下运行时,平均水压损失分别为3.41 kPa和2.81 kPa,CODMn平均去除率分别为41.5%和46.3%;后者在16 m.h-1滤速,气水体积比0.2:1的工况下运行时,平均水压损失为4.08kPa,CODMn平均去除率为41.4%。

饱和黏土水土压力合算的计算公式

由于水、土压力合算法存在一定的争议,首先对国内现行水、土压力合算公式在完全不排水条件和稳定渗流情况下计算正常固结黏土水、土压力的误差进行了定量的分析,发现计算结果在大多数情况下偏危险,误差可超过40%;然后根据等效原则,推导出了饱和正常固结黏土和超固结黏土的水、土合算公式,得到的公式与文献[2]建议的公式一致,同时证明了该公式与国外采用固结不排水抗剪强度的水、土压力合算公式也一致;对于正常固结和轻微超固结饱和黏土,由等效原则得到的水、土压力合算公式高估存在渗流时主动极限平衡状态水、土压力的合力,而对于重度超固结饱和黏土,水、土压力合算可能低估存在渗流时主动极限平衡状态水土压力的合力,最危险的状态是负超静孔压完全消散时。水、土压力合算公式是采用总应力指标计算在假定完全不排水条件下饱和黏土进入主动或被动极限平衡状态时的水、土总压力,公式并不能考虑渗流对水、土压力的影响,而渗流对水、土压力的影响显著,在实际工程中应加以考虑。

Design of a New Type of Distribution Valve for Hydraulic Breaker and Analysis of Energy Consumption

Energy consumed by distribution valves causes an energy loss for the output energy of hydraulic breakers, which has a significant influence on its efficiency. A new type of distribution valve used for hydraulic breakers, de- signed to reduce energy consumption, is analyzed on the basis of the operating principle and energy loss of the current distribution valve. The new distribution valve adopts a cone valve and the optimization technique of unequal open de- gree for the valve port. Theoretical calculations and analyses have proven that the new distribution valve can reduce en- ergy loss by 9.0127J, or energy consumption by 31%, during an impact cycle and the efficiency of the hydraulic breaker can be raised by 4.5%. It has the following characteristics: little leakage, little pressure loss and low energy consump- tion.