Back pressure

Back pressure

Back pressure usually refers to the pressure exerted on a moving fluid by obstructions or tight bends in the confinement vessel along which it is moving, such as piping or air vents, against its direction of flow. For example, an automotive exhaust muffler with a particularly high number of twists, bends, turns and right angles could be described as having particularly high back pressure [ [ Muffler] at How Stuff Works] . Back pressure in the exhaust sense of the term, is usually termed as being a "bad thing" for performance; however, in the interest of reducing exhaust sound to levels allowable by public noise ordinances, back pressure can be regulated using systems from simple butterfly valves to fully computer controlled units sensing pressure in the exhaust pipe itself.

The term is also used analogously in the field of information technology to describe the build-up of data behind an I/O switch if the buffers are full and incapable of receiving any more data; the transmitting device halts the sending of data packets until the buffers have been emptied and are once more capable of storing information [ [ Back pressure] at Webopedia] .


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  • Back pressure — Back Back, a. 1. Being at the back or in the rear; distant; remote; as, the back door; back settlements. [1913 Webster] 2. Being in arrear; overdue; as, back rent. [1913 Webster] 3. Moving or operating backward; as, back action. [1913 Webster]… …   The Collaborative International Dictionary of English

  • Back pressure — Pressure Pres sure (?; 138), n. [OF., fr. L. pressura, fr. premere. See 4th {Press}.] 1. The act of pressing, or the condition of being pressed; compression; a squeezing; a crushing; as, a pressure of the hand. [1913 Webster] 2. A contrasting… …   The Collaborative International Dictionary of English

  • back pressure — [1] The resistance to the flow of exhaust gases through the exhaust system. By rerouting the exhaust gases for noise suppression, a muffler causes back pressure, but a straight pipe alone causes only minimal back pressure. Some engines require… …   Dictionary of automotive terms

  • back pressure — noun 1. : residual pressure on the exhaust side of a steam engine piston against which the steam on the intake side must work 2. : opposition to flow of a liquid or gas due to friction, inertia, gravity, or other cause * * * back pressure noun… …   Useful english dictionary

  • back pressure — atgalinis slėgis statusas T sritis fizika atitikmenys: angl. back pressure; backpressure; return pressure vok. Gegendruck, m; Rückdruck, m rus. обратное давление, n pranc. contre pression, f; pression de retour, f …   Fizikos terminų žodynas

  • back pressure — pressure in direct opposition to the normal flow …   English contemporary dictionary

  • back pressure — A pressure exerted backward; in a field of fluid flow, a pressure exerted contrary to the pressure producing the main flow. Specifically, the pressure inside the exhaust system of a reciprocating engine that prevents the flow of burned gases from …   Aviation dictionary

  • back pressure — the pressure caused by the damming back of the blood in a heart chamber and its tributaries, due to an obstructive heart valve or failing myocardium …   Medical dictionary

  • Back pressure — Противодавление; Давление между печатным и офсетным цилиндрами …   Краткий толковый словарь по полиграфии

  • back pressure — ● ►en loc. ►PERIPH Fonction intelligente de contrôle de flux (flow control en anglais), dans le mode half duplex pour un répartiteur (switch). Il bloque l émission en cas de congestion (définition de Jean Pierre Kolly) …   Dictionnaire d'informatique francophone