净(配)水厂清水池低水位设计及自控关系探讨

净(配)水厂清水池低水位设计对消毒接触时间、消防贮水量均有影响,同时也是二级泵站水泵启停的限制条件。根据清水池水位变化情况,认为《室外给水设计规范》(GB 50013—2006)第7. 5. 1条有效容积满足消毒接触时间的规定不够严谨,满足消毒接触时间的容积应为清水池最低运行水位以下部分容积。清水池最低运行水位应取消毒水深和消防水深两者中的较大值。合理的自控关系设计是水厂正常运行的重要保障,最低运行水位是否作为停泵水位与水泵在管网系统中的功能有关,配水泵兼作消防泵时,最低运行水位不得停泵。设计应保证在最不利条件下发生火灾时,能够将消防用水及时输送至事故现场。

Discussion on Low Water Level Design and Automatic Control System in Clean Water Tank in Water Purification Plants

Low water level design of clean water tank in water purification plants has influence on disinfection contact time and fire water storage capacity,which is also the limit condition for pump start and stop in secondary pumping station. According to the variation of water level in the clean water tank,it was considered that the effective volume in provisions of section 7. 5. 1 in Code for Design of Outdoor Water Supply Engineering( GB 50013-2006) was not strict enough to meet the disinfection contact time. The volume meeting the disinfection contact time should be the part of the volume below the minimum operating water level of the clean water tank. The lowest water level of clean water tank should be the larger value of disinfection water depth and fire water depth. Reasonable automatic control system was an important guarantee for the normal operation of water purification plants. Whether the lowest operating water level was taken as that for pump shutdown was related to the function of the pump in the pipeline system. When the distribution pump was used as fire water pump,the pump should not be stopped at the lowest operating water level. The design scheme should ensure that fire protection water could be transported to the accident place in time when fire occurs under the most unfavorable conditions.