Strainers/Filters - Hoffer Flow Controls HP Series User Manual

direction. The handle is marked with the calibrated direction of flow. A rotor
may be calibrated in both directions where required. In the later application the
arrow indicates the flow direction for the 'forward' calibration.
In order for the HP Series Flowmeter to properly measure fluid flow, it is
necessary to insert the well assembly at the mean velocity point. At this depth,
the velocity and net area of the pipe section may be used to calculate the pulses
per unit-volume of the measuring section. The mean velocity point is a weak
function of flow rate, as well as other factors which influence Reynolds
number.
The mean velocity point may be determined using experimental methods to
establish the flow profile and empirically determine the desired insertion depth
(See Table C).
Table C includes the approximate location of the mean velocity point in large
diameter pipes. For small diameter piping, locate the rotor in the center of the
pipe to eliminate sidewall effects near the pipe wall. Due to profile effects, a
scaling factor must be used with center positioning.
It should be noted that the turbine rotor responds to the average velocity
appearing across its surface. While the mean velocity depth may vary, it will
often remain within the diameter of the turbine rotor and thereby minimize the
affects of not being exactly at the mean velocity depth.

STRAINERS/FILTERS

Profile/Insertion flowmeters are designed for use in a clean fluid service.
However, the service fluid may carry some particulate material which would
need to be removed before reaching the flowmeter. Under these conditions a
strainer/filter may be required to reduce the potential hazard of fouling or
damage that may be caused by foreign matter. Strainer/filters are recommended
to be used with the Hoffer Mini-Flow Series meters.
METER SIZE
MF Series
¼ to ½
" "
/ to 1¼
5
" "
8
1½ to 3
" "
4 to 12
" "
If a strainer/filter is required in the system, it should be located upstream of the
flowmeter taking care that the proper minimum distance is kept between the
strainer and flowmeter.
HP-208
MESH SIZE
100
100
70
40
24
Page 10 of 17
PARTICLE SIZE
(Maximum)
.0055
.0055
.008
.015
.028
HP Insertion Meter