Preliminary Research On Standardization For Vacuum Drainage Systems

As a drainage system, vacuum drainage system uses high speed airflow caused by pressure difference between the atmosphere and the pipeline to take away the wastewater from apparatus. Compared with conventional gravity drainage system, it has many advantages, such as①it breakthroughs the limits of the gravity, and can lift the wastewater, so the layout of pipelines is more flexible;②less destroy to environment and sight for its pipeline needn't to lay in the centre of the street and it needn't have inspect well;③simple, rapid, and convenient construction for its small diameter of pipeline (90～250mm) and shallow buried depth;④the maintenance of vacuum pipeline needn't large-scale dig for its monitoring system could locate the malfunction accurately;⑤simple maintenance and replacement of vacuum interface valve and no influence on the whole system etc. So many advantages determine the wide application foreground of the vacuum drainage system, however, because of the late study of it, there are no domestic standardizations of it.Based on the laboratory research of vacuum drainage system and drainage standards of home and abroad, this paper presents a preliminary study on the standardization of vacuum drainage system. First, the terms of vacuum drainage system are unified;Then some qualitative requirements are given for the correlative equipments and material according to their domestic development. Lastly, the flow of wastewater, layout of pipelines, and hydraulic computation are studied. Especially, before study the hydraulic computation, through experiment, we have studied the type of the wastewater running in the vacuum pipeline. Experiments show that:①the type of the two-phrase flow in the vacuum pipeline was changed with the air/water ratio. Different air/water ratio corresponds to different type of wastewater.②the friction loss of vacuum pipeline increased when the air/water ratio increased.