back pressure


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back pressure

[′bak ‚presh·ər]
(mechanics)
Pressure due to a force that is operating in a direction opposite to that being considered, such as that of a fluid flow.
(mechanical engineering)
Resistance transferred from rock into the drill stem when the bit is being fed at a faster rate than the bit can cut.

Back Pressure

 

the pressure of steam or gas at the end of the expansion process in a heat engine, such as a steam or gas turbine or a steam engine. The term “back pressure” is used to define the final pressure that exists when the expansion does not terminate in the condensation of the steam. In a steam turbine with back pressure, the exhaust steam is not condensed and, instead, is used as a source of heat for either an industrial process or another turbine.

back pressure

Pressure developed in opposition to the flow of liquid or gas in a pipe, duct, conduit, etc.; due to friction, gravity, or some other restriction to flow of the conveyed fluid.

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 the cylinders.
References in periodicals archive ?
The screw speed and back pressure were varied between 50 and 90 rpm and between 0.
To improve polymer mixing and plasticizing, it is desirable to have a high back pressure and a fixed screw rotating speed (11).
The daisy chain method uses less tubing, so it might appear that this would minimize back pressure.
The RPZ design features triple security to provide optimum protection against back pressure and back siphonage: two check valves and a discharge valve divide the unit into three chambers, each providing a separate pressure zone.
Combined, VNT with REA delivers 30% more boost at just 90% of the back pressure as compared with the previous-generation system.
In the classical Newtonian superposition theory, isothermal conditions are assumed, and the reduction in output due to back pressure is accounted for by the concept of a negative pressure flow up the extruder channel which opposes the down-channel drag flow imparted by the relative barrel to screw velocities.
A strong back pressure gives false signals to the compressor controls to cause premature compressor unloading.
Simple orbital flow regulated coring controls with back pressure and down pressure gauges make for easy and accurate coring operations and its robust, heavy-duty, welded steel construction will ensure many years of dependable use.
The Fisher[R] Type SR5 sanitary pressure regulator and Type SR8 sanitary back pressure regulator are designed for optimal performance in water-for-injection (WFI) and clean steam applications; and clean-in-place (CIP) and sanitize-in-place (SIP) systems.
The back pressure and rotation speed are closed-loop controlled during the plastication stage.
It comes in pellet form, and a 1% addition is said to reduce back pressure by up to 40% and minimize melt fracture, enabling higher film outputs.