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Hydraulically activated pipeline pigging (HAPP) is a pigging technology applied for pipeline cleaning. The basic principle is that a pressure drop is created over a by-passable pig held back against a pipeline's fluid flow. The pipeline fluid passing through the pig's cleaning head is accelerated by this pressure drop, forming strong cleaning jets.
The primary schematic drawing used for laying out a process control installation. They usually contain the following information: Mechanical equipment, including: Pressure vessels, columns, tanks, pumps, compressors, heat exchangers, furnaces, wellheads, fans, cooling towers, turbo-expanders, pig traps (see 'symbols' below)
If the barrel is not completely depressurized, the pig can be ejected from the barrel and operators have been severely injured when standing in front of an open pig door. A pig was once accidentally shot out of the end of a pipeline without a proper pig receiver and went through the side of a house 150 metres (500 ft) away. [11]
A trapdoor or hatch is a sliding or hinged door that is flush with the surface of a floor, ceiling, or roof. [1] It is traditionally small in size. [ 2 ] It was invented to facilitate the hoisting of grain up through mills, however, its list of uses has grown over time. [ 3 ]
A sewer pipe is normally at neutral air pressure compared to the surrounding atmosphere.When a column of waste water flows through a pipe, it compresses air ahead of it in the system, creating a positive pressure that must be released so it does not push back on the waste stream and downstream traps, slow drainage, and induce potential clogs.
Image of a guillotine-style mousetrap seller in the mid-19th century. In February 1855, Emerson wrote in his journal, under the heading "Common Fame": If a man has good corn or wood, or boards, or pigs, to sell, or can make better chairs or knives, crucibles or church organs, than anybody else, you will find a broad hard-beaten road to his house, though it be in the woods.
Cattle grid on country road. Cattle grids are usually installed on roads where they cross a fenceline, often at a boundary between public and private lands. [5] They are an alternative to the erection of gates that would need to be opened and closed when a vehicle passes, and are common where roads cross open moorland, rangeland or common land maintained by grazing, but where segregation of ...
Ice pigging is a technique used for cleaning pipes, distinguished from traditional pigging by the use of a semi-solid 'pig' made of ice, rather than a solid object. This ice pig is capable of flowing through pipes, navigating obstructions such as valves and variations in pipe diameter, due to its fluid-like properties.