Circulating Head : (n) An accessory attached to the top of the drill pipe or tubing to form a connection with the mud system to permit circulation of the drilling mud
US Department of Labor, Occupational Safety & Health Administration (OSHA), Oil and Gas Well Drilling and Servicing eTool, Washington, DC. This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin, USA 2001. http://www.osha.gov/SLTC/etools/oilandgas/glossary _of_terms/glossary_of_terms_a.html, (Oil Well Drilling Sci and Tech - Amer) {492}
