川杨河大型古木船室外冷冻脱水处理

An efficient way to preserve the large degraded water logged wood

1979年底上海浦东川杨河发掘工地出土了一艘古代木船.上海博物馆文物保护科学实验室对这艘大型古木船进行了室外冷冻阴干处理。采用的是利用自然气候冷冻阴干的方法.原理是将被处理物件保持在冷冻状态.利用温差产生的蒸汽压差进行升华干燥.经过十年的考验,证明这种方法对大型浸饱水木的脱水保护是切实可行的.工艺简单.干燥时间短,费用低廉,解决了国内外在处理大型浸饱水木文物方面的一些问题.

It is a difficult problem to preserve the large degraded waterlogged wooden objects.After comparetive study several treatments for large waterlogged wood,the method of freeze-drying in winter climate should be an efficient one.In this way the treated objacts were placed outside where the temperature is under O℃ for a period of time,and lyophilization relied on difference in steam pressure caused by ranger of temperature.Knowing the weather forecast,controlling the temperature change,making use of the wind,and choosing the suitable solidify material after lyophilization were very important especially in lower latitude like Shanghai. In 1979,a boat in a thousand years ago was excavated in Shanghai ancient beach.The boat's keel is 11.62m long,which water content is high to 834%.And several gunnel timbers is hard wood,which water content is high to 302%.After investagation,clean,measurement,tests of sample ect.,we preserved it using the MFIWC(Method of Freeze-drying in Winter Climate).Although the air temperature in Shanghai winter was not always ideal,the result was well,less shrink,less crack,no crooked.This practice was shown that the MFIWC is a potential way to preserve the large degraded water logged wooden object. The treated process is simple.The treated time is less(Monthes).The expense is low.Therefore,the method has solved some problems in preseving large degraded waterlogged wood especially for the developing country in the high latitute area.