Search results
Results from the WOW.Com Content Network
Diagram symbols for pressure reduction and back pressure regulators. The conceptual difference is mainly in which side the feedback is taken from. A pressure regulator is a valve that controls the pressure of a fluid to a desired value, using negative feedback from the controlled pressure. Regulators are used for gases and liquids, and can be ...
The meter is "read" as a differential pressure head in cm or inches of water. Video of a Venturi meter used in a lab experiment Idealized flow in a Venturi tube. The Venturi effect is the reduction in fluid pressure that results when a moving fluid speeds up as it flows from one section of a pipe to a smaller section.
High pressure may cause erratic flow rates. There are many different technologies which can help to measure the flow of the fluids and eventually help in controlling flow. Those technologies define the types of Mass Flow Controllers, and they include differential pressure (ΔP), differential temperature (ΔT), Coriolis , Ultrasonic ...
The pressure differential varies between aircraft types, typical values are between 540 hPa (7.8 psi) and 650 hPa (9.4 psi). [35] At 39,000 ft (11,887 m), the cabin pressure would be automatically maintained at about 6,900 ft (2,100 m), (450 ft (140 m) lower than Mexico City), which is about 790 hPa (11.5 psi) of atmosphere pressure.
The reduced pressure is guaranteed by a differential pressure relief valve, which automatically relieves excess pressure in the chamber by discharging to a drain. Four test cocks are installed to allow an inspector to verify proper operation of the valve with a differential pressure meter.
System pressure is maintained at 1,250 to 1,500 psi (8.6 to 10.3 MPa) by a pressure regulator. On aircraft 25-181 and subsequent the variable volume engine driven pump delivers fluid under a pressure of 1,450 psi (10.0 MPa) to the system and static pressure is maintained at 1,500 to 1,550 psi (10.3 to 10.7 MPa).
Air pressure was used for generating the controller output, and also for powering process modulating devices such as diaphragm-operated control valves. They were simple low maintenance devices that operated well in harsh industrial environments and did not present explosion risks in hazardous locations .
Therefore, an increase in pressure drop also increases particle collection efficiency. Ejector venturis operate at higher L/G ratios than most other particulate scrubbers (i.e., 7 to 13 L/m 3 compared to 0.4-2.7 L/m 3 for most other designs), and often also require higher liquid pressures, especially if being used to drive the process gas.