About: http://webisa.webdatacommons.org/397547224

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	The tool of this invention, in addition to serving as a testing tool and sampler, also operates as a safety valve in case the drill string parts or leaks or other emergency arises which takes the weight off of the string.
http://www.w3.org/ns/prov#wasQuotedFrom	google.es