Patent ID: 6863475
Filing Date: 2005-03-08
Classification: E02D

Abstract:
1. An apparatus for injecting fluid underground, which apparatus comprises: a pipe with a diameter of from about 0.6 cm to about 36 cm having (a) from one to ten exit ports in the peripheral wall, each port being from about 3 mm to about 5 cm in effective diameter, (b) an open upper end of the pipe adapted to receive fluid to be injected, and (c) a closed bottom end; an axial plug coaxially disposed concentrically inside said pipe and adapted to slide up and down inside the pipe, wherein said plug is tapered at the upper end of the plug and having an upper surface adapted to be acted on by the pressure of the fluid fed into said pipe; a stationary seat, disposed inside the upper end of the pipe in abutment against the inner wall of said pipe, adapted to seat said slidable plug when the plug is disposed at a position blocking said port(s); and said seat is concave and adapted to seat the tapered plug at the tapered end, and the plug and seat have surfaces mating to each other with sufficient surface contact to prevent fluid flowing therethrough; and a mechanical or pneumatic spring held in place between said slidable plug and said closed bottom end of said pipe, said spring is adapted to continuously urge said plug in an upward direction away from said closed bottom end, wherein said spring is designed to seat the axial plug against the seat thereby closing said exit port(s) when the actual differential pressure (P′) is equal or less than a design differential pressure value (P), wherein P is a pressure ranging from about 2 to about 5,000 pounds per square inch;