The JH450 is supplied with an ultrasonic
microphone, a stethoscope pickup and other accessories it serves a
variety of monitoring, maintenance and troubleshooting uses.
The Versaprobe's highly sensitive microphone can spot small leaks
before they cause trouble, from as far as 40 feet away. Its built-in
loudspeaker and signal strength meter give the user maximum
The stethoscope probe monitors bearings, vibration and flow noise.
Regular use detects impending problems such as bearing wear and
cavitation before they lead to major problems.
The Versaprobe and its accessories come in a rugged, padded
rainproof carrying case. Its built-in NiCad battery pack provides up
to 24 hours continuous operation between charges.
HOW THE VERSAPROBE WORKS
The Vesaprobe picks up ultrasonic energy in a band centered at
40kHz. After amplification the signal is heterodyned (translated)
down to audible frequencies which can be heard in the padded headset
or a built-in loudspeaker. The signal also drives a signal-strength
meter. Wide-range sensitivity adjustment is provided by a ten-turn
control. Audio volume is separately adjustable.
A high-sensitivity microphone picks up the high-frequency hiss or
noise typically emitted by pressurized gas leaks and electrical
corona discharge. By unplugging the microphone and replacing it with
a vibration pickup the Versaprobe can also be used to monitor
bearings, vibration, valves and flow conditions.
Small pressurized gas leaks emit an audible high-frequency hiss,
but emit much more energy at ultrasonic frequencies. By detecting
sound only in the 40kHz region the Versaprobe maximizes sensitivity
to leaks while rejecting competing audible noise sources.
At high sensitivity, leaks can be heard up to 40 feet away. Once a
leak has been discovered it may be pinpointed by reducing the
JH450's sensitivity and installing its rubber focusing probe
Electrical arcs and, especially, corona discharge emit high
amounts of energy in the ultrasonic spectrum and can be detected
with the Versaprobe in much the same way as pressurized leaks.
SEALS AND GASKETS
An ultrasound transmitter accessory makes it easy to locate
leaks in gaskets, vacuum chambers and other sealed systems. Simply
place the battery-powered transmitter inside, close the system and
listen with the Versaprobe. The highly directional nature of the
ultrasound energy makes it easy to pinpoint the exact location of
leaks and voids. Applications include checking for leaks in heat
exchangers, aircraft cockpits, refrigerator gaskets and more.
Ultrasound gives reliable early warning of bearing problems. Not
only does ultrasonic noise increase earlier, but it is more easily
distinguished from vibrations and mechanical noise. Bearings in good
condition give a smooth hiss or rushing sound. Damaged balls often
produce a distinct click or "ping". Other types of rough
sounds indicate wear or pits in the raceway.
A switch on the vibration pickup lets you choose
between sonic (audible) and ultrasonic modes.
VALVES, FLOW, CAVITATION
Smooth flow generates a hissing sound; generally, the faster the
flow the louder the sound. Valves can easily be checked by listening
with the stethoscope probe. When the valve is closed the hissing
sound should stop.
Cavitation and other flow problems will be heard
as a change in the flow noise. Erratic, uneven noises will be heard
along with or instead of the hissing sound.
The vibration pickup let you listen to any imaginable mechanical
device: engines, pumps, process equipment, etc. Steam traps can be
monitored; for instance, if they fail to open you will hear
continuous flow instead of periodic or cyclical noises. Different
traps produce different sounds: listening while they are functioning
properly helps you to learn to detect problems.