About: http://webisa.webdatacommons.org/411557751

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 reverse-cementing apparatus of the present invention includes a valve housing which is adapted to be connected in a casing or other pipe string that is to be cemented in a wellbore.
http://www.w3.org/ns/prov#wasQuotedFrom	google.es