Dynasonics 701_771C Series Insertion Ultrasonic Flow Meter - Manual (Page 12)

Rev. 12/97 -11- D77X
The DT7 insertion transducer that is utilized by the D77
contains piezo electric crystals for transmitting and
receiving ultrasonic sound energy. The black PVDF
plastic tip of the DT7 contains these crystals, which are
designed to be inserted to the average fluid velocity point
within a pipe. Not all liquid within a pipe is flowing at a
uniform fluid velocity. But, a straight run of pipe, full of
flowing liquid, contains a predictable liquid velocity profile.
By selecting proper upstream and downstream lengths of
straight pipe from the transducer installation point and
precise insertion depths into the pipe, very accurate and
reliable volumetric flow rates and totals can be realized.
Select a transducer mounting location with adequate
straight runs (without disturbances) of pipe, both upstream
and downstream, to achieve stable and accurate readings.
Examples of minimum upstream and downstream
requirements are included in Table 1. Note that if
adequate straight plumbing cannot be provided the D77
system will operate repeatably, but will probably not
achieve ideal accuracy.
When installing the DT7 transducer in a horizontal pipe,
the preferred orientation is at least 20 degrees from the
top or bottom of the pipe. Ensure that the mounting
location allows for adequate clearance to install and
retract the probe fully from the pipe.
PART 2 - TRANSDUCER INSTALLATION
Transducer Mounting
Considerations
Step A - Mounting
Locations