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Directional boring, also referred to as horizontal directional drilling (HDD), is a minimal impact trenchless method of installing underground utilities such as pipe, conduit, or cables in a relatively shallow arc or radius along a prescribed underground path using a surface-launched drilling rig. Directional boring offers significant ...
Push-the-bit tools use pads on the outside of the tool which press against the well bore thereby causing the bit to press on the opposite side causing a direction change. Point-the-bit technologies cause the direction of the bit to change relative to the rest of the tool by bending the main shaft running through it.
Pipe ramming (sometimes also called pipe jacking) is a trenchless method for installation of steel pipes and casings. Distances of 30 m (150 feet) or more and over 500 mm (20 inches) in diameter are common, although the method can be used for much longer and larger installations.
The ability to vary the directional tendency of the assembly comes from varying the weight on the bit. A fixed assembly has only one directional tendency. The weight on bit allows you to tune that tendency. The bottom-hole assembly (BHA) can be: slick with no stabilisers; a pendulum bottom-hole assembly for reducing the deviation of a well
In the end of 1930s, Frank Aspin developed a design with a rotary valve that rotated on the same axis as the cylinder bore, but with limited success. [10] US company Coates International Ltd has developed a spherical rotary valve for internal combustion engines which replaces the poppet valve system. This particular design is four-stroke, with ...
If the soil is rocky the tool may be deflected or fail to pound forward due to its inability to break the rock. These drawbacks can be overcome by directional boring or straight-line horizontal underground boring machines that use either wet (slick boring, slurry boring) or dry (auger boring, jack and bore) methods.
Directional drilling (or slant drilling) is the practice of drilling non-vertical bores. It can be broken down into four main groups: oilfield directional drilling, utility installation directional drilling, directional boring (horizontal directional drilling - HDD), and surface in seam (SIS), which horizontally intersects a vertical bore ...
Typical design of automobile engine connecting rod Typical aluminium rod (left), oil drip rod (centre), steel rod (right). A connecting rod, also called a 'con rod', [1] [2] [3] is the part of a piston engine which connects the piston to the crankshaft.