|
 Process
fluid flows through the variable area flow tube from bottom
to top, resulting in an axial movement of the float. Over the
length of the flow tube there is a relationship between the
float diameter and the tube inner diameter. The float diameter
is fixed and the inner diameter of the tube changes from small
at the bottom to wide at the top. If the flow rate is constant,
the differential pressure over the float equalizes with the
effective weight of the float and the float settles at a position
that represents the flow rate. When the flow increases, also
the force on the float does. This force makes the float move
to a higher position until this force has the same value as
before. When the flow decreases, the float changes position
in the opposite direction. The position of the float is therefore
virtually linear to the flow.
|
