Hydraulic pulse valve with improved pulse control

A pulse valve for producing pressure pulses, comprising:

• (a) an elongate hollow housing having a distal end and a proximal end, the proximal end having an inlet passage configured to receive a pressurized fluid, and the distal end having an outlet passage configured to convey the pressurized fluid;
• (b) a poppet seat disposed within the housing, adjacent to the outlet passage, the poppet seat including a throat having a smaller cross-sectional size than the outlet passage, causing the fluid flowing through the throat when the pulse valve is open to experience a greater velocity than the fluid flowing through the outlet passage, the poppet seat including a plurality of ports disposed at spaced apart intervals around the throat;
• (c) a valve assembly disposed within the housing, the valve assembly including a plurality of fluid passages, and a poppet that is movable between a closed position in which the poppet is positioned within the poppet seat to at least partially block pressurized fluid flow through the throat of the poppet seat, and an open position in which the poppet is withdrawn from the poppet seat so that the pressurized fluid flows through the throat of the poppet seat and through the outlet passage, wherein the pressurized fluid flowing through the throat of the poppet seat produces a lower pressure within the plurality of ports, compared to a pressure of the pressurized fluid at the inlet passage and the outlet passage, as a result of a Venturi effect, movement of the poppet between the closed position and the open position being caused by pressure differences within the valve assembly;
• and
• (d) a pilot disposed coaxially within the poppet, the pilot configured to move in conjunction with the poppet and to continue moving when the poppet reaches the open and closed position, movement of the pilot between the two spaced-apart positions and of the poppet between the closed position and the open position changing fluid paths through the valve assembly, wherein application of the pressure differences in the valve assembly at different points causes movement of the poppet and the pilot in a repetitive sequence, the pulse valve producing a pressure pulse each time that the poppet moves to its closed position in the poppet seat.

A method for producing pressure pulses, comprising the steps of:

• (a) supplying a pressurized fluid through a conduit;
• (b) using a flow of the pressurized fluid through a restricted throat coupled in fluid communication with the conduit to develop a first differential pressure in one or more passages opening into the restricted throat, wherein the first differential pressure results from a lower pressure in the one or more passages compared to a pressure of the pressurized fluid, the lower pressure being due to a Venturi effect as the pressurized fluid flow velocity increases through the restricted throat and past the one or more passages;
• (c) communicating the lower pressure to a fluid passage located in a valve assembly that is axially spaced from the restricted throat;
• (d) using the first differential pressure to move a first element located within the valve assembly from an open position to a closed position, the closed position of the first element at least partially blocking the flow of pressurized fluid through the conduit;
• and
• (e) discharging at least some of the pressurized fluid through a port in the housing sidewall into a borehole surrounding the housing.

A method for producing pressure pulses, comprising the steps of:

• (a) supplying a pressurized fluid through a conduit;
• (b) using a flow of the pressurized fluid through a restricted throat coupled in fluid communication with the conduit to develop a first differential pressure in one or more passages opening into the restricted throat, wherein the first differential pressure results from a lower pressure in the one or more passages compared to a pressure of the pressurized fluid, the lower pressure being due to a Venturi effect as the pressurized fluid flow velocity increases through the restricted throat and past the one or more passages;
• (c) communicating the lower pressure to a fluid passage located in a valve assembly that is axially spaced from the restricted throat;
• (d) using the first differential pressure to move a first element located within the valve assembly from an open position to a closed position, the closed position of the first element at least partially blocking the flow of pressurized fluid through the conduit, producing a pressure pulse in the conduit;
• (e) using a second differential pressure for moving the first element from the closed position to the open position, the second differential pressure corresponding to a difference between a pressure in the conduit distal of where the flow of the pressurized fluid through the conduit is at least partially blocked by the first element, and the pressure of the pressurized fluid proximal of where the first element is at least partially blocking the flow;
• and
• (f) movement of the second element altering fluid paths employed for applying the first and the second differential pressures to move the first and the second elements in a cycle of reciprocating motions that produces repetitive pressure pulses in the conduit.

An apparatus for producing pressure pulses, comprising an elongate housing that includes:

• (a) an internal passage for conveying a pressurized fluid between an inlet disposed on one end of the housing and an outlet disposed on an opposite end of the housing, the inlet being configured to couple to a source of the pressurized fluid, and the outlet being configured convey the pressurized fluid flowing through the outlet;
• (b) a restricted throat coupled in fluid communication with the conduit to develop a first differential pressure in one or more passages opening into the restricted throat, wherein the first differential pressure results from a lower pressure in the one or more passages compared to a pressure of the pressurized fluid, the lower pressure being due to a Venturi effect as the pressurized fluid flow velocity increases through the restricted throat and past the one or more passages;
• (c) a valve assembly that is axially spaced from the restricted throat and moves from an open position to a closed position, the closed position of the valve assembly at least partially blocking the flow of pressurized fluid through the conduit;
• and
• (d) a fluid passage allowing the lower pressure to be communicated to said valve assembly.