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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 ...
Horizontal directional drill rigs are developing towards large-scale, micro-miniaturization, mechanical automation, hard stratum working, exceeding length and depth oriented monitored drilling. [1] Measuring the inclination of a wellbore (its deviation from the vertical) is comparatively simple, requiring only a pendulum.
Rotary assemblies [2] are commonly used where formations are predictable and the rig economics are an issue. In such an assembly the weight of the drill collars gives the BHA the tendency to sag or flex to the low side of the hole, collar stiffness length and stabiliser diameter and placement are engineered as a means of controlling the flex of the BHA.
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.
Brunsviga 15 Mechanical Calculator Original Odhner-Arithmos-Typ-5. Brunsviga is a calculating machine company whose history goes back to 1892 with devices upgrading from mechanical to electrical thereafter. The firm Grimme & Natalis that manufactured the machines changed their name to Brunsviga Maschinenwerke A.G. in 1927.
For small diameters, length-to-diameter ratios of up to l/D ≤ 100 can be achieved, in special cases even up to l/D = 900. [ 2 ] [ 3 ] [ 4 ] With large diameters, the l/D ratio is usually limited by the travel or the bed length of the deep hole drilling machine.
Engine displacement is calculated based on bore, stroke length and the number of cylinders: [1] displacement = π ( 1 / 2 × bore ) 2 × stroke × n cylinders. The stroke ratio, determined by dividing the bore by the stroke, traditionally indicated whether an engine was designed for power at high engine speeds or torque at lower engine ...
[13] [30] Nevertheless, in 1883, this TBM was used to bore a railway ventilation tunnel — 2 m (7 ft) in diameter and 2.06 km (6,750 ft) long — between Birkenhead and Liverpool, England, through sandstone under the Mersey River. [31] The Hudson River Tunnel was constructed from 1889 to 1904 using a Greathead shield TBM. The project used air ...