Abstract: A valve apparatus adapted for connection in a drill stem comprises a sleeve member slidably guided in a body having a longitudinal fluid passage and lateral openings that communicate with an annular space surrounding the sleeve member. The sleeve member also comprises lateral holes of small diameter and bottom orifices or channels of large diameter. In a first position of the sleeve member, the fluid flows from the drill stem towards the annular space through the holes of small diameter. When the rate of flow reaches a sufficient value, the sleeve member is moved against a biasing spring to a second position, where the small holes are closed and the large channels permit the passage of the fluid through the valve, towards the lower part of the drill stem, without any noticeable pressure drop. The sleeve member is retained in the said second position through the pressures in the drill stem and in the annular space acting on different areas of the sleeve member.

Abstract: A wellpoint jetting head having a plurality of spade-like teeth annularly positioned around the forward end of the head and projecting longitudinally therefrom for dislodging and chopping of the soil during hydrostatic jetting in combination with a tilting, side-to-side, rotational and/or up-and-down manipulation of the wellpoint. The teeth are beveled in a counterbalancing inward-outward staggered arrangement with the cutting surface formed by the teeth ends defining a cutting plane canted with respect to the longitudinal axis of the head. The teeth are circumferentially spaced providing lateral confronting side faces for dislodging soil particulate during use.

Abstract: Improved sealing means in rock drilling equipment of the kind comprising casing sections positioned between the drilling unit and the cutter head and housing the drill rod sections. A combined seal consisting of a metal part and a resilient part is positioned between the casing and the cutter head to prevent water and mud from penetrating into the casing. In addition, sealing means are provided to prevent drill water from flowing between the drill rod and the casing in the direction towards the drill chamber, and further means are provided to close off communication between the drill chamber and the annular chamber between the casing and the drill hole wall.

Abstract: The apparatus is a rocket with a drill head provided with a group of jet nozzles. One nozzle of this group is the face-forming one, while the plurality of the rows of the rest of the nozzles belong to imaginary circles concentric with the longitudinal axis of the rocket. The spacing of the nozzles in each row equals 4 to 7 critical diameters of the jet nozzle of the respective row, while the spacing of any pair of the adjacent rows of the nozzles in a projection of the drill head upon a plane perpendicular to the longitudinal axis of the rocket is 4 to 7 times greater than the mean diameter of the nozzles of the said pair of rows of nozzles.

Abstract: A ball valve type, full opening bore, oil well formation tester utilizes a J-slot mechanism and vertical tool string manipulations to open and close a substantially unrestricted axial bore through the testing tool to allow formation fluid flow through the tool at the command of the tool operator.