四虎最新免费网址_亚洲午夜狼友精品福利在线_日韩少妇HEYZO视频无码_欧美日韩熟妇在线视频_亚洲国内午夜aⅴ无码私人影院_久久久精品国产一级无遮挡_精品粉嫩小又紧又爽AV_好男人资源免费观看_波多野结衣亚洲中文_日本免费一区二区大片视频

The Bottom Sampler acc. to Van Veen is a qualitative sampler to achieve low-disturbed sediment samples in soft or medium hard grounds from any desired depth. It consists of two clamshell jaws connected by a hinge. During descent both levers are locked wide apart and the jaws are open. Upon touching the water bed the locking mechanism is released and when the rope is pulled taut to raise the sampler the jaws close. During retrieval the jaws are holding the sample and prevent sample wash-out. Additional flaps on top of the heavy version 437 333 allow to inspect the sample before retrieving.