INFICON Whisper Ultrasonic Leak Detector - Manual (Page 4)

4
Introduction
The Whisper will detect and locate sources of ultrasonic disturbance through the use of
sophisticated circuitry.
An ultrasonic disturbance is created when objects collide. Vacuum leaks create
collisions between molecules flowing through an orifice. Pressure leaks create collisions
between molecules exiting an orifice. All gases and liquids create disturbances if forced
into, or out of, an orifice. All solid materials create disturbances when any friction exists.
The Whisper is therefore capable of detecting and locating sources of ultrasonic
disturbances created by gases, liquids or solids.
The Whisper has different ways of indicating these disturbances. When used without
headphones, the detector's LEDs will illuminate and the unit will beep in response to
sources of ultrasonic noise. When headphones are plugged in, the unit's heterodyne
feature is enabled, bringing ultrasonic frequencies to a range audible to the human ear.
This is likely how you want to use the Whisper most of the time. You can also use the
metal contact probe on solid objects. Please refer to the appropriate sections of this
manual for more information on these features and how to best use them.
General Information
The Whisper is sensitive only to ultrasound (40.5 kHz) and is unaffected by audible
noise.
INTERNAL NOISE CONTROL (I.N.C.) allows the use of this instrument in extremely
noisy environments such as mechanical rooms, around operational chillers, etc. Drag
your finger upwards on the sensitivity touch pad to increase sensitivity when
experiencing little or no environmental noise. Drag your finger downwards on the
sensitivity touch pad to reduce sensitivity in response to an increase in environmental
noise. The I.N.C. works much like a two way radio squelch allowing only the strongest
and closest signals to penetrate the electronic wall built by the I.N.C. circuitry.
Many variables can affect the amount of ultrasound generated by the leakage of gas
through an orifice. Such factors include the pressure/vacuum versus the surrounding
environment, how smooth the edges of the orifice are, the diameter of the orifice, the
leak detector’s distance from the orifice and the presence of airflow, which may dissipate
the ultrasound.
As you use the Whisper, keep in mind that these factors may affect your ability to detect
ultrasonic leaks.
Locating Leaks
NOTE: Bumping the accessory probes or nose piece into objects while seeking leaks
will cause false alarms. Leaks will be indicated by an a beeping audio alarm
and flashing LEDs. Disregard occasional short alarms.