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Stave Bearing
A stave bearing is a simple journal bearing where a shaft rotates in a bearing housing. Rather than the usual arrangement where the fixed part of the bearing surrounds most of the circumference of the shaft in one or two pieces, a stave bearing uses a large number of axial staves to support the shaft. A large housing is made with grooves running along the shaft, these grooves being filled with strips of suitable material, originally wood. Uses Stave bearings have long been associated with ships and their propeller shafts. The bearing is suitable for slow speeds and high loads. When used on ships, the bearing is designed to run immersed in water, allowing its use outboard of the stern gland or stuffing box. Stave bearings are also well suited to applications such as rudder shafts, where rotation is intermittent and reciprocating, rather than continuous and unidirectional. Other bearing types, such as some ball bearings, don't perform well under this type of use and may fail prematu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Journal Bearing
A plain bearing, or more commonly sliding contact bearing and slide bearing (in railroading sometimes called a solid bearing, journal bearing, or friction bearing), is the simplest type of bearing, comprising just a bearing surface and no rolling elements. Therefore, the journal (i.e., the part of the shaft in contact with the bearing) slides over the bearing surface. The simplest example of a plain bearing is a shaft rotating in a hole. A simple linear bearing can be a pair of flat surfaces designed to allow motion; e.g., a drawer and the slides it rests on or the ways on the bed of a lathe. Plain bearings, in general, are the least expensive type of bearing. They are also compact and lightweight, and they have a high load-carrying capacity. Design The design of a plain bearing depends on the type of motion the bearing must provide. The three types of motions possible are: * ''Journal'' (''friction'', ''radial'' or ''rotary'') ''bearing'': This is the most common type of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stave (wood)
] A stave is a narrow length of wood with a slightly bevelled edge to form the sides of barrels, tanks, tubs, vats and pipelines, originally handmade by coopers. They have been used in the construction of large holding tanks and penstocks at hydro power developments. They are also used in the construction of certain musical instruments with rounded bodies or backs. See also *Rubicon Hydroelectric Scheme, which has wood stave penstocks on operating power stations *Lake Margaret Power Station The Lake Margaret Power Stations comprise two hydroelectric power stations located in Western Tasmania, Australia. The power stations are part of the King Yolande Power Scheme and are owned and operated by Hydro Tasmania. Officially the Upper ..., which had a wood stave penstock replaced in 2010 References Structural engineering Woodworking {{civil-engineering-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Propeller Shaft
A drive shaft, driveshaft, driving shaft, tailshaft (Australian English), propeller shaft (prop shaft), or Cardan shaft (after Girolamo Cardano) is a component for transmitting mechanical power and torque and rotation, usually used to connect other components of a drivetrain that cannot be connected directly because of distance or the need to allow for relative movement between them. As torque carriers, drive shafts are subject to torsion and shear stress, equivalent to the difference between the input torque and the load. They must therefore be strong enough to bear the stress, while avoiding too much additional weight as that would in turn increase their inertia. To allow for variations in the alignment and distance between the driving and driven components, drive shafts frequently incorporate one or more universal joints, jaw couplings, or rag joints, and sometimes a splined joint or prismatic joint. History The term ''driveshaft'' first appeared during the mid-19th centu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stern Gland
A stuffing box or gland package is an assembly which is used to house a gland seal. It is used to prevent leakage of fluid, such as water or steam, between sliding or turning parts of machine elements. Components A stuffing box of a sailing boat will have a stern tube that is slightly bigger than the prop shaft. It will also have packing nut threads or a gland nut. The packing is inside the gland nut and creates the seal. The shaft is wrapped by the packing and put in the gland nut. Through tightening it onto the stern tube, the packing is compressed, creating a seal against the shaft. , WindCheck Magazine, Retrieved April 27, 2016. Creating a proper plunger alignment is critical for correct flow and a long wear life. Stuffing box components are of stainless steel, brass or other application-specific m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stuffing Box
A stuffing box or gland package is an assembly which is used to house a gland seal. It is used to prevent leakage of fluid, such as water or steam, between sliding or turning parts of machine elements. Components A stuffing box of a sailing boat will have a stern tube that is slightly bigger than the prop shaft. It will also have packing nut threads or a gland nut. The packing is inside the gland nut and creates the seal. The shaft is wrapped by the packing and put in the gland nut. Through tightening it onto the stern tube, the packing is compressed, creating a seal against the shaft. , WindCheck Magazine, Retrieved April 27, 2016. Creating a proper plunger alignment is critical for correct flow and a long wear life. Stuffing box components are of stainless steel, brass or other application-specific m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ball Bearing
A ball bearing is a type of rolling-element bearing that uses balls to maintain the separation between the bearing races. The purpose of a ball bearing is to reduce rotational friction and support radial and axial loads. It achieves this by using at least two races to contain the balls and transmit the loads through the balls. In most applications, one race is stationary and the other is attached to the rotating assembly (e.g., a hub or shaft). As one of the bearing races rotates it causes the balls to rotate as well. Because the balls are rolling they have a much lower coefficient of friction than if two flat surfaces were sliding against each other. Ball bearings tend to have lower load capacity for their size than other kinds of rolling-element bearings due to the smaller contact area between the balls and races. However, they can tolerate some misalignment of the inner and outer races. History Although bearings had been developed since ancient times, the first mod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lignum Vitae
Lignum vitae () is a wood, also called guayacan or guaiacum, and in parts of Europe known as Pockholz or pokhout, from trees of the genus ''Guaiacum''. The trees are indigenous to the Caribbean and the northern coast of South America (e.g: Colombia and Venezuela) and have been an important export crop to Europe since the beginning of the 16th century. The wood was once very important for applications requiring a material with its extraordinary combination of strength, toughness, and density. It is also the national tree of the Bahamas, and the Jamaican national flower. The wood is obtained chiefly from ''Guaiacum officinale'' and ''Guaiacum sanctum'', both small, slow-growing trees. All species of the genus ''Guaiacum'' are now listed in Appendix II of CITES (the Convention on International Trade in Endangered Species of Wild Fauna and Flora) as potentially endangered species. ''G. sanctum'' is listed as Near Threatened by the IUCN Red List. Demand for the wood has been reduc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tufnol
Phenol formaldehyde resins (PF) or phenolic resins (also infrequently called phenoplasts) are synthetic polymers obtained by the reaction of phenol or substituted phenol with formaldehyde. Used as the basis for Bakelite, PFs were the first commercial synthetic resins (plastics). They have been widely used for the production of molded products including billiard balls, laboratory countertops, and as coatings and adhesives. They were at one time the primary material used for the production of circuit boards but have been largely replaced with epoxy resins and fiberglass cloth, as with fire-resistant FR-4 circuit board materials. There are two main production methods. One reacts phenol and formaldehyde directly to produce a thermosetting network polymer, while the other restricts the formaldehyde to produce a prepolymer known as novolac which can be moulded and then cured with the addition of more formaldehyde and heat.A. Gardziella, L.A. Pilato, A. Knop, Phenolic Resins: Chemis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrile Rubber
Nitrile rubber, also known as nitrile butadiene rubber, NBR, Buna-N, and acrylonitrile butadiene rubber, is a synthetic rubber derived from acrylonitrile (ACN) and butadiene. Trade names include Perbunan, Nipol, Krynac and Europrene. This rubber is unusual in being resistant to oil, fuel, and other chemicals. NBR is used in the automotive and aeronautical industry to make fuel and oil handling hoses, seals, grommets, and self-sealing fuel tanks. It is used in the nuclear industry to make protective gloves. NBR's stability at high temperatures from makes it an ideal material for aeronautical applications. Nitrile butadiene is also used to produce moulded goods, footwear, adhesives, sealants, sponges, expanded foams, and floor mats. Its resilience makes NBR a useful material for disposable lab, cleaning, and examination gloves. Nitrile rubber is more resistant than natural rubber to oils and acids, and has superior strength, but has inferior flexibility. History Nitrile rubb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UHMWPE
Ultra-high-molecular-weight polyethylene (UHMWPE, UHMW) is a subset of the thermoplastic polyethylene. Also known as high-modulus polyethylene, (HMPE), it has extremely long chains, with a molecular mass usually between 3.5 and 7.5 million amu. The longer chain serves to transfer load more effectively to the polymer backbone by strengthening intermolecular interactions. This results in a very tough material, with the highest impact strength of any thermoplastic presently made. UHMWPE is odorless, tasteless, and nontoxic. It embodies all the characteristics of high-density polyethylene (HDPE) with the added traits of being resistant to concentrated acids and alkalis, as well as numerous organic solvents. It is highly resistant to corrosive chemicals except oxidizing acids; has extremely low moisture absorption and a very low coefficient of friction; is self-lubricating (see boundary lubrication); and is highly resistant to abrasion, in some forms being 15 times more resistant to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bluebird K4
''Blue Bird K4'' was a powerboat commissioned in 1939 by Sir Malcolm Campbell, to rival the Americans' efforts in the fight for the world water speed record. The name "K4" was derived from its Lloyd's unlimited rating, and was carried in a prominent circular badge on the forward hull. As this was Campbell's second boat, it was also known as ''Blue Bird II''. He used the name for a series of land speed record cars, his record boats and also his motor yacht. K4 was built by Vosper & Company as a replacement for ''Blue Bird K3'', which had set three other water speed records for Malcolm Campbell before the K4 was built. It also used the same Rolls-Royce R engine. Design K4 was a three-point hydroplane. Conventional planing powerboats, such as ''Miss England'' or ''Blue Bird K3'', have a single keel, with an indent or "step" projecting from the bottom of the hull. At speed, the force on this step is enough to lift the bow upward, reducing the wetted surface area of the hull an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrolytic Corrosion
Galvanic corrosion (also called bimetallic corrosion or dissimilar metal corrosion) is an electrochemical process in which one metal corrodes preferentially when it is in electrical contact with another, in the presence of an electrolyte. A similar galvanic reaction is exploited in primary cells to generate a useful electrical voltage to power portable devices. This phenomenon is named after Italian physician Luigi Galvani (1737-1798). Overview Dissimilar metals and alloys have different electrode potentials, and when two or more come into contact in an electrolyte, one metal (that's more reactive) acts as anode and the other (that's less reactive) as cathode. The electropotential difference between the reactions at the two electrodes is the driving force for an accelerated attack on the anode metal, which dissolves into the electrolyte. This leads to the metal at the anode corroding more quickly than it otherwise would and corrosion at the cathode being inhibited. The presence ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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