基于抽滤的土壤高效过滤装置研制及应用研究

Development and Research of the High-efficiency Soil Filtering Device Based on Suction Filtration

针对土壤化验前处理的高效过滤需求,设计了一种以抽滤为核心方法的自动化土壤浸提过滤装置。该装置在结构上主要分为两部分:包括土壤溶液储液腔、滤纸承载板、密封垫圈在内的台面上部分和包括负压腔、导流腔、滤液储液腔在内的台面下部分。台面上、下两部分通过直行气缸连接。该装置利用在抽滤腔形成的负压对土壤浸提后的溶液进行抽滤,在1 min内实现对土液比为1∶10样品的完全过滤,滤液回收率大于75%,在很大程度上提高了过滤速度和滤液回收率。抽滤结束,在滤纸上形成厚度约为5 mm的完整滤饼,可在更换滤纸时一并移走,操作便捷、兼容全自动化。10个土壤样品分别经过高效抽滤装置和常压过滤装置处理后,两组样品中速效钾含量的检测数值结果基本一致,相对相差都小于10%,符合农业农村部标准中速效钾检测精度的要求,证明该高效过滤装置对速效钾的测定结果不产生影响,可以用于土壤化验的快速前处理。

Aiming at the problem of low filtering speed and efficiency in the process of soil nutrient pretreatment,this paper proposes a high-efficiency soil filtration device,which realizes rapid filtration of soil samples by vacuum filtration.The device is mainly divided into two parts in structure:the table top part includes the soil solution storage chamber,the filter paper carrying plate,and the sealing gasket,and the under-table part includes the negative pressure chamber,the diversion chamber,and the filtrate storage chamber.The two parts are connected by a straight cylinder.The device filters the soil leaching solution by forming a negative pressure in the suction filter chamber.The sample with a soil-liquid ratio of 1∶10 was completely filtered within 1 minute,and the filtrate recovery rate was greater than 75%,which greatly improved the filtration rate and filtrate recovery rate.In the end,a complete filter cake with a thickness of about 5 mm was formed on the filter paper,which can be removed when replacing the filter paper.The operation was convenient and compatible with full automation.After leaching 10 soil samples,they were respectively processed by the high-efficiency suction filtration device and atmospheric filtration.Through analysis of their available potassium content,the test results were basically the same.The relative difference between the two sets of data was less than 10%,which was in line with the standards of Ministry of Agriculture.It was proved that the high-efficiency filtration device did not affect the determination results of available potassium,and could be used for rapid pretreatment of soil testing.