29-05-2012, 05:18 PM
UNDERSTANDING DIFFERENT FLOW METERS
FLOW METERS.pptx (Size: 1.7 MB / Downloads: 95)
INTODUCTION:
one of the most important measurements in the chemical process industries (CPI) is rate of flow.
Flow rate can be important to measure, and infect can be critical to measure ,thought a process from dosing components into a reactor to material transfer in between process steps, to discharging products at the end
Flow metering technologies fall into 4 classification
Velocity flow meter
Many kinds of flow meters sense a fluids average velocity through a pipe.
When specifying velocity meters in chemical engineers must
be concerned with the fluids velocity profile.
In this case, the fluid velocity at the walls closely matches the fluid velocity at center and at all points in between. The velocity at any point is the average velocity.
depending on the pipe diameter and the fluids density, viscocity, and momentum, the flow velocity with in a pipe can vary significantly between the pipe wall and its center.
PIPE GEOMETRY PLAYS A ROLE:
Manufacturers will specify the length of straight pipe upstream and down stream of velocity flow meter for achieving high geometries in a chemical plant
The flow meter may have to be located near an elbow,tee,valve or change in pipe diameter. In this case the flow will not be fully developed and results in a distorting profile .Various flow straightening devices installed upstream of the flow meter