The finely-machined construction of a positive displacement flowmeter will suffer damage from
grit or other abrasive materials present in the fluid, which means these flowmeters are applicable
only to clean fluid flowstreams. Even with clean fluid flowing through, the sealing surfaces of
the mechanisms are subject to wear and accumulating inaccuracies over time. However, there
is really nothing more definitive for measuring volumetric flow rate than an instrument built
to measure individual volumes of fluid with each mechanical cycle. As one might guess, these
instruments are completely immune to swirl and other large-scale fluid turbulence, and may be
installed nearly anywhere in a piping system (no need for long sections of straight-length pipe
upstream or downstream). Positive displacement flowmeters are also very linear, since mechanism
cycles are directly proportional to fluid volume