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Underground pneumatic boring is used to bore an underground hole between two points without disturbing the surface. The tools are often referred to as a hog, air hog, or pneuma gopher. This open-air chamber is referred to as the borehole and is used to either run ducting for a product or the product itself between two points.
Underground pneumatic drills are used in the installation of all public utilities electricity, gas, phone, and cable television; these are referred to as products. It is also used to install residential lawn irrigation systems and auxiliary home power lines. Boring is utilized in instances when it is difficult or cost-prohibitive to plow or trench the product into the ground. Some of these instances are under driveways, roads, sidewalks, and landscaping.
Underground pneumatic boring is typically a low-cost alternative to directional boring.
Underground pneumatic drill uses compressed air to bore its way through the ground underneath obstructions. The tool is cylindrical and ranges from one to eight inches in diameter and between three and six feet long. It is made from metal, typically steel. Manufacturers have different font styles and control mechanisms. The compressed air is run through a hydraulic hose with an oiler attachment to send oil through with the compressed air, akin to a jackhammer.
Inside the cylinder is a piston. A valve opens and the air blows into the chamber, forcing the piston forward, which in turn propels the tool forward. The valve then shuts, and the piston is pushed at a slower speed back into the tool. The valve reopens, the piston pounds again, and the tool moves forward. This process is continually repeated until the drill has run the intended distance. Both the lighter reverse hit of the piston and the friction of the ground surrounding the tool keep it moving forward instead of stopping. The speed of the tool can be controlled by a valve that connects the tool's hose to the air supply. This valve is outside the tool and remains accessible to the operator. As the tool pounds through the ground, it compresses the soil. This compaction maintains the same diameter as the tool and leaves the borehole through which the product is passed.
The purpose of the drill is to create a tunnel under surface obstructions. First, the operator surveys the area and the obstacle (road, sidewalk, driveway). Utility locators must supervise any underground work, and the path most clear of utilities is chosen to send the tool through. The first hole is dug on one side of the obstacle. This hole must be large enough to fit the tool and the operator to aim the tool. The hole also must be deep enough that, as the tool compacts the ground, the surface remains undisturbed. The depth of the starting bore pit depends on the type of soil that is being worked in and how well it compacts. The operator aims the tool to the desired exit point and allows it to perform its function, creating a borehole under the ground without disturbing the surface. The tool is tracked by the operator, who feels the tool pounding and can approximate the tool's location under the ground. The operator also monitors the surface to make sure that it is undisturbed. As the tool nears the exit point it is slowed down and an exit pit is dug to locate both the tool and the bore. As the tool enters the exit pit the operator chooses to either dig up the tool to retrieve it or reverse the tool back into the first bore pit to retrieve it. Now between the two pits is a completed bore under the obstacle which can be used to run the product.
Pneumatic drill tools do have drawbacks which can cause difficulties completing the bore. First, the distance of the drill is limited by the length of the hose that supplies the tool with air. Also, the tool is not steerable. Once it has exited the bore pit, the operator no longer has control over it. The tool can be deflected by rocks and soil density to a path the operator had not intended. If this deflection is in the direction of the surface, the tool can cause damage to the obstacle being bored. One more drawback is that the tool can dive to an unrecoverable depth. If it is deflected side to side the tool could also run into other utilities. These hazards make it important for the operator to maintain close observation of the tool. The type of ground on which drill works can also lead to problems. If the soil is too loose, the tool cannot compact the soil, stalling it out or leaving no borehole. 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.
A piston is a component of reciprocating engines, reciprocating pumps, gas compressors, hydraulic cylinders and pneumatic cylinders, among other similar mechanisms. It is the moving component that is contained by a cylinder and is made gas-tight by piston rings. In an engine, its purpose is to transfer force from expanding gas in the cylinder to the crankshaft via a piston rod and/or connecting rod. In a pump, the function is reversed and force is transferred from the crankshaft to the piston for the purpose of compressing or ejecting the fluid in the cylinder. In some engines, the piston also acts as a valve by covering and uncovering ports in the cylinder.
An air compressor is a machine that takes ambient air from the surroundings and discharges it at a higher pressure. It is an application of a gas compressor and a pneumatic device that converts mechanical power into potential energy stored in compressed air, which has many uses. A common application is to compress air into a storage tank, for immediate or later use. When the delivery pressure reaches its set upper limit, the compressor is shut off, or the excess air is released through an overpressure valve. The compressed air is stored in the tank until it is needed. The pressure energy provided by the compressed air can be used for a variety of applications such as pneumatic tools as it is released. When tank pressure reaches its lower limit, the air compressor turns on again and re-pressurizes the tank. A compressor is different from a pump because it works on a gas, while pumps work on a liquid.
A borehole is a narrow shaft bored in the ground, either vertically or horizontally. A borehole may be constructed for many different purposes, including the extraction of water, other liquids, or gases. It may also be part of a geotechnical investigation, environmental site assessment, mineral exploration, temperature measurement, as a pilot hole for installing piers or underground utilities, for geothermal installations, or for underground storage of unwanted substances, e.g. in carbon capture and storage.
Fluid power is the use of fluids under pressure to generate, control, and transmit power. Fluid power is conventionally subdivided into hydraulics and pneumatics. Although steam is also a fluid, steam power is usually classified separately from fluid power. Compressed-air and water-pressure systems were once used to transmit power from a central source to industrial users over extended geographic areas; fluid power systems today are usually within a single building or mobile machine.
A jackhammer is a pneumatic or electro-mechanical tool that combines a hammer directly with a chisel. It was invented by William McReavy, who then sold the patent to Charles Brady King. Hand-held jackhammers are generally powered by compressed air, but some are also powered by electric motors. Larger jackhammers, such as rig-mounted hammers used on construction machinery, are usually hydraulically powered. These tools are typically used to break up rock, pavement, and concrete.
A drilling rig is an integrated system that drills wells, such as oil or water wells, or holes for piling and other construction purposes, into the earth's subsurface. Drilling rigs can be massive structures housing equipment used to drill water wells, oil wells, or natural gas extraction wells, or they can be small enough to be moved manually by one person and such are called augers. Drilling rigs can sample subsurface mineral deposits, test rock, soil and groundwater physical properties, and also can be used to install sub-surface fabrications, such as underground utilities, instrumentation, tunnels or wells. Drilling rigs can be mobile equipment mounted on trucks, tracks or trailers, or more permanent land or marine-based structures. The term "rig" therefore generally refers to the complex equipment that is used to penetrate the surface of the Earth's crust.
An air line is a tube, or hose, that contains and carries a compressed air supply. In industrial usage, this may be used to inflate car or bicycle tyres or power tools worked by compressed air, for breathing apparatus in hazardous environments and to operate many other pneumatic systems.
A tube well is a type of water well in which a long, 100–200 millimetres (3.9–7.9 in)-wide, stainless steel tube or pipe is bored underground. The lower end is fitted with a strainer, and a pump lifts water for irrigation. The required depth of the well depends on the depth of the water table.
Geotechnical investigations are performed by geotechnical engineers or engineering geologists to obtain information on the physical properties of soil earthworks and foundations for proposed structures and for repair of distress to earthworks and structures caused by subsurface conditions; this type of investigation is called a site investigation. Geotechnical investigations are also used to measure the thermal resistance of soils or backfill materials required for underground transmission lines, oil and gas pipelines, radioactive waste disposal, and solar thermal storage facilities. A geotechnical investigation will include surface exploration and subsurface exploration of a site. Sometimes, geophysical methods are used to obtain data about sites. Subsurface exploration usually involves soil sampling and laboratory tests of the soil samples retrieved.
A drifter drill, sometimes called a rock drill, is a tool used in mining and civil engineering to drill into rock. Rock drills are used for making holes for placing dynamite or other explosives in rock blasting, and holes for plug and feather quarrying.
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 environmental advantages over traditional cut and cover pipeline/utility installations. The technique is routinely used when conventional trenching or excavating is not practical or when minimal surface disturbance is required.
A pneumatic circuit is an interconnected set of components that convert compressed gas into mechanical work. In the normal sense of the term, the circuit must include a compressor or compressor-fed tank.
Baptist well drilling is a very simple, manual method to drill water wells. The Baptist drilling rig can be built in any ordinary arc welding workshop and materials for a basic version costs about 150 US dollars. In suitable conditions, boreholes over 100 m deep have been drilled with this method.
A down-the-hole drill, usually called DTH by most professionals, is basically a jackhammer screwed on the bottom of a drill string. The fast hammer action breaks hard rock into small cuttings and dust that are evacuated by a fluid. The DTH hammer is one of the fastest ways to drill hard rock. The system is thought to have been invented independently by Stenuick Frères in Belgium and Ingersoll Rand in the USA in the mid-1950s.
A suction excavator or vacuum excavator is a construction vehicle that removes heavy debris or other materials from a hole on land.
A vacuum truck, vacuum tanker, vactor truck, vactor, vac-con truck, vac-con is a tank truck that has a pump and a tank. The pump is designed to pneumatically suck liquids, sludges, slurries, or the like from a location into the tank of the truck. The objective is to enable transport of the liquid material via road to another location. Vacuum trucks transport the collected material to a treatment or disposal site, for example a sewage treatment plant.
A booster pump is a machine which increases the pressure of a fluid. It may be used with liquids or gases, and the construction details vary depending on the fluid. A gas booster is similar to a gas compressor, but generally a simpler mechanism which often has only a single stage of compression, and is used to increase pressure of a gas already above ambient pressure. Two-stage boosters are also made. Boosters may be used for increasing gas pressure, transferring high pressure gas, charging gas cylinders and scavenging.
A bash valve is a valve within a piston engine, used to control the admission of the working fluid. They are directly actuated valves, operated by contact between the piston and the valve tip.
Tunnels are dug in types of materials varying from soft clay to hard rock. The method of tunnel construction depends on such factors as the ground conditions, the ground water conditions, the length and diameter of the tunnel drive, the depth of the tunnel, the logistics of supporting the tunnel excavation, the final use and shape of the tunnel and appropriate risk management. Tunnel construction is a subset of underground construction.
Ice drilling allows scientists studying glaciers and ice sheets to gain access to what is beneath the ice, to take measurements along the interior of the ice, and to retrieve samples. Instruments can be placed in the drilled holes to record temperature, pressure, speed, direction of movement, and for other scientific research, such as neutrino detection.
