Appendix B Transducer Maintenance; Signal Deterioration - Accusonic 8510+ series Reference Manual

A P P E N D I X B
Transducer Maintenance
Ultrasonic transducers require little maintenance. They need attention only when the signal shows signs of
deterioration. The following safeguards apply:

The connector-ends of transducers - those which lie outside of the conduit - should be protected from
the weather and from vermin so as to retain electrical integrity.

Devices not in service should be protected from the weather and extreme humidity (95% max) and
stored at a temperature between -20°C and 60°C.

Signal Deterioration

After a period of time, the signal level of the transducer signal may deteriorate. This is usually due to the
growth of algae or buildup of mineral deposits on the face of the transducer. The rate at which foreign
matter builds up on a transducer face varies, depending on the ambient water conditions. Under normal
water conditions, Accusonic recommends that transducer signals be checked for deterioration monthly at
first, and then annually. Under severe conditions, more frequent testing may be appropriate. The simplest
method is to monitor the AGC values for each path. See path variables Gain in Chapter 7, Variables.
In many cases, signal deterioration may be caused by loose, wet, frayed, or worn transducer cables or
connections. When signal deterioration is observed or suspected, be sure to check the wiring before
assuming that foreign matter has built up on the transducer face or that there is trouble with the transducer
itself. Consult the procedures given in Transducer and Cabling Checkout in Chapter 4, on 4-5 to test and
prove out the transducer wiring and external junctions. If signal strength drops below acceptable levels, the
appropriate action to be taken depends on the type of the transducer.
For internal mount transducers (Models 7630 and 7634) - most of which are installed with dual active
elements - try switching elements to see if the problem clears up. If not, the only option is to run the
flowmeter with a path shut down (which degrades accuracy), switch on path substitution (which also
degrades accuracy), or to dewater the pipe and clean, inspect, and possibly replace the unit.
Note: When switching to a backup element in a dual-element transducer, it is necessary to
change the path parameters Path length and Path angle accordingly; unless the elements on both
ends of the path are changed.
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