ApplicationNo. 551898 filed on 02/21/1975
US Classes:166/317, Destructible element137/515.5, Valve seat formed on or carried by a coupling element137/71, Having pressure responsive valve166/325, One way, e.g., check valve type175/218With valve
ExaminersPrimary: Leppink, James A.
Attorney, Agent or Firm
AbstractA drilling fluid saver valve connected to the lower end of a kelly allows down flow of mud or other drilling fluid when pumps are actuated to circulate drilling fluid. The valve closes when the pumps are off, thereby to retain drilling fluid thereabove in the kelly. This prevents loss of fluid when the kelly and valve are disconnected from the drill pipe. The valve includes a tubular body and a top sub screwed therein. A replaceable seat is carried by the lower end of the sub. A poppet type valve closure is urged upwardly against the seat by a helical spring strong enough to close the valve against the weight of drilling mud in the kelly. The closure has a tubular stem extending down through the spring. The poppet valve closure has a central flow passage therethrough, communicating with the stem and controlled by an upwardly opening check valve, to communicate drill pipe pressure to the kelly when the pumps are off. The check valve closure is frangible for easy break-out if wire line tools need to be run. The poppet valve stem has ports to allow fluid passing below the closure to enter the stem and flow down therethrough, by-passing an annular chamber between the stem and body in which the spring is disposed. The chamber is sealed by upper and lower seal means between the stem and body and is kept at atmospheric pressure.