Shock vs Vibration

What is the difference?

When discussing the vibrations that your pressure gauge must endure, think of the feeling you get from riding around on your lawn mower. The constant vibration from a motor, pump, or compressor can wear on the internal mechanical components of your pressure gauge.  Although vibrations are damaging over a period of time, it is not the primary reason for a pressure gauge failure.

A shock to a pressure gauge is a surge of pressure that a gauge would feel on the initial start of a compressor or opening of a valve on a charged system.  The shock to a pressure gauge is the most damaging and is the by far the common reason for pressure gauge failure.  A shock to the gauge increases the possibility of over ranging the bourdon tube.  Once this happens your gauge is toast.

Glycerin Filled Pressure Gauge

The reason for liquid or glycerin filling a gauge is to dampen the mechanical vibrations.  Although viscosity of glycerin filling add some resistance to the mechanical workings of the gauge, thereby slows down the reaction time but offers very little defense against shock to a pressure gauge.