yourporn久久国产精品,18禁在线播放三上AV插,国产 亚洲 综合 在线观看,精品成人午夜免费视频

The Sediment Corer is easy to handle and can be operated manually in shallow waters with a push rod or on a rope simply using gravity in greater water depths. During descent the plastic valve flap on top of the transparent plexiglass tube is held open to let the water flow freely through the tube. To retrieve the sample the corer is lifted from the sediment and the water pressure at the valve flap closes the tube. A vacuum is holding the sediment sample in place and is preventing washout.

Out of the water the provided piston is put into the lower end of the tube. The tube holder with rope stirrup is taken off and the tube with the core sample is placed onto the piston. When the tube is now pressed onto the piston the core sample will be removed for examination.