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Anti-vibration Compound
An anti-vibration compound is a temperature-resistant mixture of a liquid with fine particles, which is used to reduce oscillations in calender rolls and to dampen vibrations in fabricated structures like machine beds and housings. Use Vibration may limit the performance of a calender or paper machine. It can have numerous sources such as bulk variations in the sheet, bearing problems, or misalignment of the driveshaft. Vibration manifests itself as a high frequency periodic movement of the roll body with an amplitude from less than one to several µm. When anti-vibration compound is introduced to the center bores of the rolls, vibration is transferred from the solid roll structure to the incompressible fluid component of the anti-vibration compound. Its solid particles are less mobile due to their inertia. Thus the fluid is forced to oscillate around the solid components. The flow energy is absorbed by micro eddies by which the vibration is damped. The benefits are a smoothe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oscillations
Oscillation is the repetitive or periodic variation, typically in time, of some measure about a central value (often a point of equilibrium) or between two or more different states. Familiar examples of oscillation include a swinging pendulum and alternating current. Oscillations can be used in physics to approximate complex interactions, such as those between atoms. Oscillations occur not only in mechanical systems but also in dynamic systems in virtually every area of science: for example the beating of the human heart (for circulation), business cycles in economics, predator–prey population cycles in ecology, geothermal geysers in geology, vibration of strings in guitar and other string instruments, periodic firing of nerve cells in the brain, and the periodic swelling of Cepheid variable stars in astronomy. The term ''vibration'' is precisely used to describe a mechanical oscillation. Oscillation, especially rapid oscillation, may be an undesirable phenomenon in proce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calender
A calender is a series of hard pressure rollers used to finish or smooth a sheet of material such as paper, textiles, rubber, or plastics. Calender rolls are also used to form some types of plastic films and to apply coatings. Some calender rolls are heated or cooled as needed. Calenders are sometimes misspelled ''calendars''. Etymology The word "calender" itself is a derivation of the word κύλινδρος ''kylindros'', the Greek word that is also the source of the word "cylinder". History In eighteenth century China, workers called "calenderers" in the silk- and cotton-cloth trades used heavy rollers to press and finish cloth. In 1836, Edwin M. Chaffee, of the Roxbury India Rubber Company, patented a four-roll calender to make rubber sheet. Chaffee worked with Charles Goodyear with the intention to "produce a sheet of rubber laminated to a fabric base". Calenders were also used for paper and fabrics long before later applications for thermoplastics. With the expansio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vibration
Vibration is a mechanical phenomenon whereby oscillations occur about an equilibrium point. The word comes from Latin ''vibrationem'' ("shaking, brandishing"). The oscillations may be periodic function, periodic, such as the motion of a pendulum—or random, such as the movement of a tire on a gravel road. Vibration can be desirable: for example, the motion of a tuning fork, the Reed (music), reed in a woodwind instrument or harmonica, a mobile phone, or the cone of a loudspeaker. In many cases, however, vibration is undesirable, wasting energy and creating unwanted sound. For example, the vibrational motions of engines, electric motors, or any Machine, mechanical device in operation are typically unwanted. Such vibrations could be caused by Engine balance, imbalances in the rotating parts, uneven friction, or the meshing of gear teeth. Careful designs usually minimize unwanted vibrations. The studies of sound and vibration are closely related. Sound, or pressure waves, are ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paper Machine
A paper machine (or paper-making machine) is an industrial machine which is used in the pulp and paper industry to create paper in large quantities at high speed. Modern paper-making machines are based on the principles of the Fourdrinier Machine, which uses a moving woven mesh to create a continuous paper web by filtering out the fibres held in a paper stock and producing a continuously moving wet mat of fibre. This is dried in the machine to produce a strong paper web. The basic process is an industrialised version of the historical process of hand paper-making, which could not satisfy the demands of developing modern society for large quantities of a printing and writing substrate. The first modern paper machine was invented by Louis-Nicolas Robert in France in 1799, and an improved version patented in Britain by Henry and Sealy Fourdrinier in 1806. The same process is used to produce paperboard on a paperboard machine. Process sections Paper machines usually have at leas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bearing (mechanical)
A bearing is a machine element that constrains relative motion to only the desired motion, and reduces friction between moving parts. The design of the bearing may, for example, provide for free linear movement of the moving part or for free rotation around a fixed axis; or, it may ''prevent'' a motion by controlling the vectors of normal forces that bear on the moving parts. Most bearings facilitate the desired motion by minimizing friction. Bearings are classified broadly according to the type of operation, the motions allowed, or to the directions of the loads (forces) applied to the parts. Rotary bearings hold rotating components such as shafts or axles within mechanical systems, and transfer axial and radial loads from the source of the load to the structure supporting it. The simplest form of bearing, the ''plain bearing'', consists of a shaft rotating in a hole. Lubrication is used to reduce friction. In the ''ball bearing'' and ''roller bearing'', to reduce sliding ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Driveshaft
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] |
Fluid
In physics, a fluid is a liquid, gas, or other material that continuously deforms (''flows'') under an applied shear stress, or external force. They have zero shear modulus, or, in simpler terms, are substances which cannot resist any shear force applied to them. Although the term ''fluid'' generally includes both the liquid and gas phases, its definition varies among branches of science. Definitions of ''solid'' vary as well, and depending on field, some substances can be both fluid and solid. Viscoelastic fluids like Silly Putty appear to behave similar to a solid when a sudden force is applied. Substances with a very high viscosity such as pitch appear to behave like a solid (see pitch drop experiment) as well. In particle physics, the concept is extended to include fluidic matters other than liquids or gases. A fluid in medicine or biology refers any liquid constituent of the body (body fluid), whereas "liquid" is not used in this sense. Sometimes liquids given for flui ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inertia
Inertia is the idea that an object will continue its current motion until some force causes its speed or direction to change. The term is properly understood as shorthand for "the principle of inertia" as described by Newton in his first law of motion. After some other definitions, Newton states in his first law of motion: The word "perseveres" is a direct translation from Newton's Latin. Other, less forceful terms such as "to continue" or "to remain" are commonly found in modern textbooks. The modern use follows from some changes in Newton's original mechanics (as stated in the ''Principia'') made by Euler, d'Alembert, and other Cartesians. The term inertia comes from the Latin word ''iners'', meaning idle, sluggish. The term inertia may also refer to the resistance of any physical object to a change in its velocity. This includes changes to the object's speed or direction of motion. An aspect of this property is the tendency of objects to keep moving in a straight li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eddy (fluid Dynamics)
In fluid dynamics, an eddy is the swirling of a fluid and the reverse current created when the fluid is in a turbulent flow regime. The moving fluid creates a space devoid of downstream-flowing fluid on the downstream side of the object. Fluid behind the obstacle flows into the void creating a swirl of fluid on each edge of the obstacle, followed by a short reverse flow of fluid behind the obstacle flowing upstream, toward the back of the obstacle. This phenomenon is naturally observed behind large emergent rocks in swift-flowing rivers. An eddy is a movement of fluid that deviates from the general flow of the fluid. An example for an eddy is a vortex which produces such deviation. However, there are other types of eddies that are not simple vortices. For example, a Rossby wave is an eddy which is an undulation that is a deviation from mean flow, but doesn't have the local closed streamlines of a vortex. Swirl and eddies in engineering The propensity of a fluid to swirl is used ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polymer
A polymer (; Greek '' poly-'', "many" + ''-mer'', "part") is a substance or material consisting of very large molecules called macromolecules, composed of many repeating subunits. Due to their broad spectrum of properties, both synthetic and natural polymers play essential and ubiquitous roles in everyday life. Polymers range from familiar synthetic plastics such as polystyrene to natural biopolymers such as DNA and proteins that are fundamental to biological structure and function. Polymers, both natural and synthetic, are created via polymerization of many small molecules, known as monomers. Their consequently large molecular mass, relative to small molecule compounds, produces unique physical properties including toughness, high elasticity, viscoelasticity, and a tendency to form amorphous and semicrystalline structures rather than crystals. The term "polymer" derives from the Greek word πολύς (''polus'', meaning "many, much") and μέρος (''meros'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
