Abstract: A technique for pumping an output fluid, especially a particle-laden abrasive liquid. This technique utilizes an output pump and a drive pump which are interconnected through a common chamber containing a drive fluid, specifically water. The output pump includes an output piston within its own pumping chamber for pumping the output liquid by causing the output piston to move through a complete forward stroke. The drive pump includes a drive piston within its own chamber and means for causing the output piston to move the drive piston through its own complete forward stroke. This pressurizes the drive fluid within the common chamber in a way which causes the output piston to move in the forward direction of its stroke. The two pumps are configured such that the forward stroke of the drive piston defines a greater swept volume than the forward stroke of the output piston, thereby to ensure that the output piston will always move through its entire forward stroke before the drive piston.

Abstract: A dual conduit drill string used in drilling holes for geothermal, oil and gas wells, and the like, comprises a removable inner conduit to permit the use of salvage or repair equipment within the outer conduit. The outer conduit comprises standard API drill pipe sections which are each slightly modified to receive the removable inner conduit sections. Each inner conduit section is provided with flexible hangers for suspending the weight of the inner conduit from a support ledge formed on the interior surface of the drill pipe. The hangers permit upward removal motion and rotation of the inner conduit with respect to the drill pipe, but prevent downward motion. Individual inner conduit sections are joined together at lockable stab joints in which locking is accomplished by the rotatable engagement of a key and locking socket. Preferably, the inner conduit is manufactured in uniform lengths and mounted in drill pipe sections of non-uniform lengths by means of drill pipe adaptor subs.

Abstract: The technique for replacing an existing underground cable and a specific apparatus for doing so are disclosed herein. The apparatus includes a main body or cable follower which is interconnected with the cable to be replaced for slidable movement along the latter. At the same time, the apparatus provides means for reaming around the cable, preferrably by means of one or more fluid jets. Once the soil surrounding the cable has been loosened using this apparatus, the cable can be easily pulled out of the ground. At the same time, the replacement cable can be attached to the existing cable and pulled into its place.

Abstract: An underground cable installing apparatus is disclosed herein along with its method of operation. The apparatus utilizes a power driven land vehicle and an elongated cable laying plow handle supported by and for movement with the vehicle in a way which places a lowermost end portion of the blade in the ground with its cutting edge disposed in the direction of movement of the vehicle. In accordance with one operational feature of the apparatus disclosed herein, a plurality of high impact fluid jets are used to aid the cable laying plow blade in cutting through the earth. In accordance with another feature, the blade is also subjected to vibration, preferably by placing a vibratory member on the in-ground portion of the blade.

Abstract: The technique for replacing an existing underground cable and a specific apparatus for doing so are disclosed herein. The apparatus includes a main body or cable follower which is interconnected with the cable to be replaced for slidable movement along the latter. At the same time, the apparatus provides means for reaming around the cable, preferrably by means of one or more fluid jets. Once the soil surrounding the cable has been loosened using this apparatus, the cable can be easily pulled out of the ground. At the same time, the replacement cable can be attached to the existing cable and pulled into its place.

Abstract: A cable following apparatus especially suitable for use in replacing existing underground cable by reaming around and along the length of the cable is disclosed herein. This apparatus includes a main body or cable follower which is interconnected with the cable to be replaced for slidable movement along the latter. In order to accomplish this, the apparatus includes a specifically designed mechanism for releasably gripping the cable at least at one end preferably two points along the cable in a specifically controlled fashion. At the same time, the apparatus provide means for reaming around the cable, preferably by means of one or more floor jets. Once the soil surrounding the cable has been loosened using this apparatus, the cable can be easily pulled out of the ground. A replacement cable can be attached to the existing cable and therefore pulled into place.

Abstract: An underground boring apparatus including a forwardmost boring head is disclosed herein along with a particular technique for guiding the boring head through the earth along both linear and non-linear paths. In a specific embodiment, the apparatus utilizes an elongated shaft arrangement supporting the boring head at its front end and a tubular housing supporting an intermediate segment of said shaft arrangement for pivotal movement about one of a number of different axes whereby to cause the boring head to pivot relative to the housing. An arrangement of piston/cylinder units is disposed within the housing for pivoting the shaft arrangement in a controlled fashion whereby to determine the direction of movement of the boring head through the earth.

Abstract: The technique for replacing an existing underground cable and a specific apparatus for doing so are disclosed herein. The apparatus includes a main body or cable follower which is interconnected with the cable to be replaced for slidable movement along the latter. At the same time, the apparatus provides means for reaming around the cable, preferrably by means of one or more fluid jets. Once the soil surrounding the cable has been loosened using this apparatus, the cable can be easily pulled out of the ground. At the same time, the replacement cable can be attached to the existing cable and pulled into its place.