The principle of "Shallow Layer Sediment" was discovered by Mr. Howatson of UK in 1886. Manufacture and utilization of relating various sediment devices with tilting plates and tubes in many countries have been over a period more than a half centuries. 浅层沉淀原理于1886年由英国人Howatson发现,相关的各类倾斜板和斜管沉降装置的制作和使用,遍及许多国家,已有半个多世纪的历史。