KOHTECT BT-77, Руководство по эксплуатации

Страница: 18 / 23

KOHTECT BT-77
3.0 ROLLER BEARING CONDITION MONITORING BY THE SHOCK PULSE
METHOD (MEAUREMENT METHOD)
3.1 What is Shock Pulse Method (SPM) and it basis
Designation of the Shock Pulse Method (SPM) is a signal processing technique used
to measure rolling bearing condition and the quality of their lubrication in the motor,
pumps, separators, turbo compressors for diesel boost, etc. Using the instruments to
measure shock pulses, one can determine the air or gas leaks via looseness in the
high-pressure vessels or pipes. The research work conducted at Central Research &
Design Institute of �avy allowed expanding the performance capabilities of the
instruments. Shock pulse checkers have set to be used for the evaluation of condition
of high-pressure fuel pumps, diesel injectors, valves of piston compressors.
The Shock Pulse Method (SPM) was developed by a Swedish instrument company
and based on monitoring and analyzing of high frequency compression (shock) waves
caused by mechanical impact. Acceleration of material particles generates pressure or
shock wave that propagates as ultra-sonic frequency band through the object. In the
initial phase of impact, the acceleration of material particles depends on impact velocity
and is independent of the mass of colliding objects. Within short period and there is no
evident deformation. The value wave shock is the impact velocity of colliding objects.
In the second phase of the collision, the surfaces of two objects are deformed; the
energy movement declines the object and generates vibrations that are diagnosed by
the vibration analysis.
Piezoelectric transducer is used to measure shock pulse; vibration and noise background
do not effect on it. The transducers electrically and mechanically tune to 28…32 kHz.
Shock wave caused by the mechanical impact generates the decaying shock vibrations
in transducer. The maximum magnitude of this decaying vibration is relative to the velocity of
the impact (v). Since the decaying transient is well defined and has constant decay value, it
14