Abstract: A dual pipe drill string system having increased fluid flow. The dual pipe system comprises a plurality of pipe sections, each pipe section having an inner rod and an outer pipe. The inner rod and the outer pipe of each pipe section may be coupled to the inner rod and outer pipe of an adjacent pipe section. An annulus between the inner rod and the outer pipe defines a fluid flow path through the dual pipe system. The outer pipe defines a shoulder at each end of an individual pipe section. The inner rod defines at least one stop for maintaining the inner rod within the outer pipe. A spacing assembly disposed around the circumference of the inner rod defines paths for fluid flow and maintains a minimum distance between the stop and the shoulder at one end of outer pipe of the pipe section.

Abstract: A method and apparatus for detecting and avoiding an underground object during a horizontal directional drilling operation. The apparatus comprises a boring tool with a ground penetrating radar detection system. The boring tool is operatively connected to a drill string and advanced through the earth to create a borehole. The radar detection system includes at least one transmitter, at least one detector, and a processor. The transmitter is located on a surface of the boring tool and is adapted to transmit electromagnetic waves. At least one detector is located on the surface of the boring tool, and detects the electromagnetic waves reflected by underground objects. The processor determines the location of the underground object from characteristics of the reflected waves. Using this information, the drill string may be pulled back up the borehole or redirected to avoid the object. The boring tool may be caused to breakout of the existing borehole using a pivoting boring tool.

Abstract: A dual pipe drill string system having increased fluid flow. The dual pipe system comprises a plurality of pipe sections, each pipe section having an inner rod and an outer pipe. The inner rod and the outer pipe of each pipe section may be coupled to the inner rod and outer pipe of an adjacent pipe section. An annulus between the inner rod and the outer pipe defines a fluid flow path through the dual pipe system. The outer pipe defines a shoulder at each end of an individual pipe section. The inner rod defies at least one stop for maintaining the inner rod within the outer pipe. A spacing assembly disposed around the circumference of the inner rod defines paths for fluid flow and maintains a minimum distance between the stop and the shoulder at one end of outer pipe of the pipe section.

Abstract: A method and apparatus for detecting and avoiding an underground object during a horizontal directional drilling operation. The apparatus comprises a boring tool with a ground penetrating radar detection system. The boring tool is operatively connected to a drill string and advanced through the earth to create a borehole. The radar detection system includes at least one transmitter, at least one detector, and a processor. The transmitter is located on a surface of the boring tool and is adapted to transmit electromagnetic waves. At least one detector is located on the surface of the boring tool, and detects the electromagnetic waves reflected by underground objects. The processor determines the location of the underground object from characteristics of the reflected waves. Using this information, the drill string may be pulled back up the borehole or redirected to avoid the object. The boring tool may be caused to breakout of the existing borehole using a pivoting boring tool.

Abstract: A method and apparatus for locating an underground object. The apparatus comprises an excavation head, a wave emitter, a receiver, and a processor. The excavation head is adapted for soft excavation of soil. The excavation head may use mechanical means to dislodge soil, pressurized air or water, or a combination of methods. The wave emitter, located proximate the excavation head, transmits waves into the soil. The receiver receives waves reflected by underground objects. Information about the reflected waves is processed by the processor to determine the location of the underground object.

Abstract: A control device and method for opening and closing the nozzle of a fuel injector. The control device includes first and second cavities which are formed in the body of the fuel injector, with the second cavity being located close to the nozzle. First and second variable pressure supply chambers are connected to the nozzle and to the two cavities by several fluid passages. A spool valve and a needle valve are positioned in the first and second cavities, respectively, with the spool valve abutting a stem which projects into and terminating in the second cavity. Also situated in the second cavity between the stem and the needle valve is a spring which forms a link therebetween. The spool valve is pressure-actuated by a difference of pressure in the first and second pressure chambers to move between an open and a closed position. In the open position, fluid flow from one of the pressure chambers is permitted through the spool valve and to the second cavity.