US 12,000,281 B2 · Horizontal directional drilling system with improved system for limiting torque

Abstract

A method of controlling a horizontal directional drill having a rotary drive system. The rotary drive system includes a variable displacement pump providing pressurized fluid to a motor, a displacement control that adjusts motor displacement, a torque limiter valve that opens at a torque limit to provide pressurized fluid to the displacement control to allow the system to limit torque, and cross-port relief valves that open at a cross-port relief pressure to limit pressure applied across a motor inlet and a motor outlet. The method includes adjusting the torque limiter pressure to vary the maximum torque applied to a drill string based on operating parameters of the horizontal direction drill, and adjusting the cross-port relief pressure to be higher than the torque limiter pressure each time that the torque limiter pressure is adjusted.

Claims19

Dependent claims

A drilling machine having a rotary drive for applying torque to a drill string and a system for controlling the torque, the system comprising:

a controller having an operator input that allows an operator to specify an operating torque limit;
a variable displacement hydraulic pump that provides hydraulic fluid to a motor at a variable flow rate;
a torque limiter valve that provides hydraulic fluid to de-stroke the pump when a pressure of the hydraulic fluid provided to the motor is equal to a first predetermined set point, wherein the first predetermined set point is adjustable;
a cross-port relief that allows hydraulic fluid to bypass the motor when a pressure of the hydraulic fluid provided to the motor is equal to a second predetermined set point;
wherein the controller automatically adjusts the first predetermined set point to a setting for a make-up torque, wherein a torque limit is set at a level for proper make-up during a drill string make-up process, or to a setting for the operating torque limit during a boring process;
and
wherein the controller automatically adjusts the second predetermined set point to be a predetermined amount higher than the first predetermined set point.

4 more elements

A method of controlling a horizontal directional drill having a rotary drive system for applying torque to a drill string, the rotary drive system including a variable displacement pump providing pressurized fluid to a motor that generates the torque, a displacement control that adjusts motor displacement to limit flow to maintain a controlled pressure, a torque limiter valve that opens at a torque limit pressure to provide pressurized fluid to the displacement control to allow the system to limit torque when a system pressure is equal to a pressure that will generate a desired maximum torque, and cross-port relief valves that open at a cross-port relief pressure to limit pressure applied across a motor inlet and a motor outlet, the method comprising:

adjusting the torque limiter pressure to set the maximum torque applied to the drill string based on operating parameters of the horizontal direction drill;
and
adjusting the cross-port relief pressure to be higher than the torque limiter pressure each time that the torque limiter pressure is adjusted.

A drilling machine having a rotary drive for applying torque to a drill string and a system for controlling the torque, the system comprising:

a variable displacement hydraulic pump that provides hydraulic fluid to a motor at a variable flow rate;
a controller having an input provided by a pressure sensor configured to read a hydraulic pressure of the fluid provided to the motor, the controller configured to provide a current signal to the hydraulic pump to de-stroke the pump when a pressure of the hydraulic fluid provided to the motor is equal to a first predetermined set point, wherein the first predetermined set point is adjustable;
a cross-port relief that allows hydraulic fluid to bypass the motor when a pressure of the hydraulic fluid provided to the motor is equal to a second predetermined set point;
wherein the controller automatically adjusts the first predetermined set point to a setting for a make-up torque, wherein a torque limit is set at a level for proper make-up during a drill string make-up process, or to a setting for an operating torque limit during a boring process;
and
wherein the controller automatically adjusts the second predetermined set point to be a predetermined amount higher than the first predetermined set point.

3 more elements

Dependencies are inferred from the claim text.

Horizontal directional drilling system with improved system for limiting torque

Life of this patent

Horizontal directional drilling system with improved system for limiting torque

Life of this patent

Abstract

Claims19