HORIZONTAL DIRECTIONAL DRILLING DIAGRAM INSTALL
Connections must be durable to resist wear from repeated makeup and breakout.The drilling process is a technique really helpful when we need to drill beneath of a structure without disturb it, as is the case when we need to install a pipe crossing a roadway without disturb it or stop the circulation of the traffic. Each length of pipe must be flexible enough to be steered effectively, yet have enough rigidity not to break or become permanently bent. HDD pipe must withstand tremendous forces generated during the drilling and pullback. When the pilot hole is finished, the pipe pulls reamer and product through the hole to complete the installation. Drilling fluid is delivered to down-hole tools through the string of the drill pipe guidance-system components are attached to the drill string behind the drill bit. Drill pipe links the drill rig to down-hole tools, transmitting engine horsepower to them for thrust, pullback, and rotational torque. Quick-connect couplers simplify the task of connecting and disconnecting down-hole tools, speeding the process and reducing the risk of accidents during tool change. Different pin values can be mixed and matched to create a number of different values, all in the same connector. If three 1,000-pound pins are used, the connector would come apart at 3,000 pounds. If a single 1,000-pound pin is used, the connector will come apart at 1,000 pounds. The sum of the values of the pins is the value at which the connector will come apart. The assembly of the connector is completed by using one or more of the breakaway pins. The pins are designed to break at a specific load. The connectors are usually a three-part product, held together by a group of pins. These products are designed to protect pipe from overload during HDD installation and are used between the pullback swivel and the duct puller or pulling head. Breakaway swivels, which break or give way when a certain pullback force is exceeded, are often used for plastic product pipes. For large-diameter pipes FIGURE 3-20 Typical Hole-Opener Diagram FIGURE 3-21 Typical Duct PullersĪ flexible link between the swivel and pulling head is sometimes used to reduce the pipe's buoyancy effect, which may exert upward bending forces on the reamer. Swivels are placed between the reamer and the duct puller or pulling head to prevent the product pipe from rotating during pullback. One of the most recent advances in pulling equipment is to install bundles of conduit on long-haul telecommunications projects. Today's pulling tools are stronger and more trouble-free. A failure can abruptly stop a project short of FIGURE 3-18 Typical Hole Openers FIGURE 3-19 Typical Hole OpenerĬompletion, resulting in time-consuming and costly delays. Performance of pulling components is critical to every HDD installation. Swivels connect pulling tools to the drill string, and the pipe or other product to be installed is attached to pulling tools. Figure 3-21 illustrates typical pullers, and Figure 3-22 illustrates typical cable grips. Duct pullers are available in one-piece units that are screwed into the end of the product pipe and multiple-piece units that expand in the pipe. Duct pullers are placed inside plastic pipes to assist with pulling during HDD installation. As the mandrel is pulled forward, it forces the teeth outward, causing them to grip the inside wall of the duct. The most common type of puller has a set of wedge-shaped teeth on a conical mandrel that is inserted inside the end of the duct. Today, every duct manufacturer recommends the use of a puller that distributes the load around the entire circumference of the duct. This put the entire load of the pull on the holes drilled through the duct and was for that reason quite ineffective. FIGURE 3-17 Typical Reamers duct and nuts and bolts passed through a pull chain.
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