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Magnetic Coupling
A magnetic coupling is a coupling that transfers torque from one shaft to another, but using a magnetic field rather than a physical mechanical connection. Magnetic shaft couplings are most often used for liquid pumps and propeller systems, since a static, physical barrier can be placed between the two shafts to separate the fluid from the motor operating in air. Magnetic shaft couplings preclude the use of shaft seals, which eventually wear out and fail from the sliding of two surfaces against each another. Magnetic couplings are also used for ease of maintenance on systems that typically require precision alignment, when physical shaft couplings are used, since they allow a greater off axis error between the motor and driven shaft. Applications Some diver propulsion vehicles and remotely operated underwater vehicles use magnetic coupling to transfer torque from the electric motor to the prop. Magnetic gearing is also being explored for use in utility scale wind turbines as a me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coupling
A coupling is a device used to connect two shafts together at their ends for the purpose of transmitting power. The primary purpose of couplings is to join two pieces of rotating equipment while permitting some degree of misalignment or end movement or both. In a more general context, a coupling can also be a mechanical device that serves to connect the ends of adjacent parts or objects. Couplings do not normally allow disconnection of shafts during operation, however there are torque-limiting couplings which can slip or disconnect when some torque limit is exceeded. Selection, installation and maintenance of couplings can lead to reduced maintenance time and maintenance cost. Uses Shaft couplings are used in machinery for several purposes. A primary function is to transfer power from one end to another end (ex: motor transfer power to pump through coupling). Other common uses: * To alter the vibration characteristics of rotating units * To connect the driving and the driven ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diver Propulsion Vehicle
A diver propulsion vehicle (DPV), also known as an underwater propulsion vehicle, sea scooter, underwater scooter, or swimmer delivery vehicle (SDV) by armed forces, is an item of diving equipment used by scuba divers to increase range underwater. Range is restricted by the amount of breathing gas that can be carried, the rate at which that breathing gas is consumed, and the battery power of the DPV. Time limits imposed on the diver by decompression requirements may also limit safe range in practice. DPVs have recreational, scientific and military applications. DPVs include a range of configurations from small, easily portable scooter units with a small range and low speed, to faired or enclosed units capable of carrying several divers longer distances at higher speeds. The earliest recorded DPVs were used for military purposes during World War II and were based on torpedo technology and components. Structure A DPV usually consists of a pressure-resistant watertight casing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Remotely Operated Underwater Vehicle
A remotely operated underwater vehicle (technically ROUV or just ROV) is a tethered underwater mobile device, commonly called ''underwater robot''. Definition This meaning is different from remote control vehicles operating on land or in the air. ROVs are unoccupied, usually highly maneuverable, and operated by a crew either aboard a vessel/floating platform or on proximate land. They are common in deepwater industries such as offshore hydrocarbon extraction. They are linked to a host ship by a neutrally buoyant tether or, often when working in rough conditions or in deeper water, a load-carrying umbilical cable is used along with a tether management system (TMS). The TMS is either a garage-like device which contains the ROV during lowering through the splash zone or, on larger work-class ROVs, a separate assembly which sits on top of the ROV. The purpose of the TMS is to lengthen and shorten the tether so the effect of cable drag where there are underwater currents is minimiz ... [...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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetic Drive Pump
Centrifugal pumps are used to transport fluids by the conversion of rotational kinetic energy to the hydrodynamic energy of the fluid flow. The rotational energy typically comes from an engine or electric motor. They are a sub-class of dynamic axisymmetric work-absorbing turbomachinery. The fluid enters the pump impeller along or near to the rotating axis and is accelerated by the impeller, flowing radially outward into a diffuser or volute chamber (casing), from which it exits. Common uses include water, sewage, agriculture, petroleum, and petrochemical pumping. Centrifugal pumps are often chosen for their high flow rate capabilities, abrasive solution compatibility, mixing potential, as well as their relatively simple engineering. A centrifugal fan is commonly used to implement an air handling unit or vacuum cleaner. The reverse function of the centrifugal pump is a water turbine converting potential energy of water pressure into mechanical rotational energy. H ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thrust Bearing
A thrust bearing is a particular type of rotary bearing. Like other bearings they permanently rotate between parts, but they are designed to support a predominantly axial load. Thrust bearings come in several varieties. *''Thrust ball bearings'', composed of bearing balls supported in a ring, can be used in low thrust applications where there is little axial load. *''Cylindrical thrust roller bearing''s consist of small cylindrical rollers arranged flat with their axes pointing to the axis of the bearing. They give very good carrying capacity and are cheap, but tend to wear due to the differences in radial speed and friction which is higher than with ball bearings. *'' Tapered roller thrust bearings'' consist of small tapered rollers arranged so that their axes all converge at a point on the axis of the bearing. The length of the roller and the diameter of the wide and the narrow ends and the angle of rollers need to be carefully calculated to provide the correct taper so that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetic Stirrer
A magnetic stirrer or magnetic mixer is a laboratory device that employs a rotating magnetic field to cause a stir bar (or ''flea'') immersed in a liquid to spin very quickly, thus stirring it. The rotating field may be created either by a rotating magnet or a set of stationary electromagnets, placed beneath the vessel with the liquid. It is used in chemistry and biology as a convenient way to stir small volumes and where other forms of stirring, such as overhead stirrers and stirring rods, may not be viable. Design left, Four magnetic stir bars next to a metre stick A magnetic stirrer consists of a magnetic bar placed within the liquid which provides the stirring action. The stir bar's motion is driven by another rotating magnet or assembly of electromagnets in the stirrer device, beneath the vessel containing the liquid. Stir bars are typically coated in PTFE, or, less often, in glass; the coatings are intended to be chemically inert, not contaminating or reacting wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electromagnetic Clutch
Electromagnetic clutches operate electrically but transmit torque mechanically. This is why they used to be referred to as electro-mechanical clutches. Over the years, EM became known as electromagnetic versus electro-mechanical, referring more about their actuation method versus physical operation. Since the clutches started becoming popular over 60 years ago, the variety of applications and clutch designs has increased dramatically, but the basic operation remains the same today. Single-face clutches make up approximately 90% of all electromagnetic clutch sales. Electromagnetic clutches are most suitable for remote operation since no mechanical linkages are required to control their engagement, providing fast, smooth operation. However, because the activation energy dissipates as heat in the electromagnetic actuator when the clutch is engaged, there is a risk of overheating. Consequently, the maximum operating temperature of the clutch is limited by the temperature rating of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetic Particle Clutch
A magnetic particle clutch is a special type of electromagnetic clutch which does not use friction plates. Instead, it uses a fine powder of magnetically susceptible material (typically stainless steel) to mechanically link an otherwise free-wheeling disc attached to one shaft, to a rotor attached to the other shaft. This clutch is a form of a powder clutch. Torque is transmitted mechanically, through a metal powder filling. In the magnetically controlled version, an applied magnetic field is used to lock the particles in place. Unlike a pure magnetic coupling though, this field takes no part in transmitting torque magnetically. When a magnetic field is applied by a coil to the powder, it forms chains connecting the disc and rotor. The strength of the chains depends on the strength of the magnetic field. If there is not a magnetic field being applied to the powder, then powder is free floating. In this state the clutch is able to spin freely without any engagement of the input shaf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetic Devices
Magnetism is the class of physical attributes that are mediated by a magnetic field, which refers to the capacity to induce attractive and repulsive phenomena in other entities. Electric currents and the magnetic moments of elementary particles give rise to a magnetic field, which acts on other currents and magnetic moments. Magnetism is one aspect of the combined phenomena of electromagnetism. The most familiar effects occur in ferromagnetic materials, which are strongly attracted by magnetic fields and can be magnetized to become permanent magnets, producing magnetic fields themselves. Demagnetizing a magnet is also possible. Only a few substances are ferromagnetic; the most common ones are iron, cobalt, and nickel and their alloys. The rare-earth metals neodymium and samarium are less common examples. The prefix ' refers to iron because permanent magnetism was first observed in lodestone, a form of natural iron ore called magnetite, Fe3O4. All substances exhibit some type of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
