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.
Why is calibration important?
Calibrating a device has 3 main purposes:
-Ensures readings from an instrument are consistent with other measurements.
-Determines accuracy of the readings.
-Establishes the reliability of the instrument i.e. that it can be trusted.
Comparison of a known value from a “standard” to an unknown value from the unit under test. Accuracy of the standard varies but the typical standard will be at least ten (10) times as accurate as the device being tested.
Regular Calibration Provides Confidence
Accuracy changes for all measuring devices over time through normal wear and tear. Changes can also be caused traumatic events like electric or mechanical shock. Working environments with contaminants such as oils, metal chips or chemicals can also affect accuracy. Other significant factors are the quality of the instrument, frequency of use and skill of the user. The end result of no calibration is over confidence and can be a problem for any organization.
Calibration improves the reliability of measurements to improve product quality and consistency.
Calibrating your instruments saves time and money in re-work or replacement of bad products.
Top question asked from customers about NAVSEA standard item 009-04 dated 30 JULY, 2015 is:
Do I need accredited calibrations?
Lab accreditation is done by an external organization which verifies a lab can calibrate a specific measurement with a specific level of uncertainty.
When a customer asks for an “accredited” calibration, they are asking that the lab to use equipment to generate data to that level of uncertainty, report those values and affix a special logo.
Requiring that a lab is accredited for a specific function, as stated in 009-04 on page 2 of 10 paragraph 3.1.7 , is not the same thing.
Accredited calibrations are typically the most expensive services a lab offers.
To check if a lab is accredited for a specific function is as easy as looking them up on the web and reviewing their scope of accreditation.
If a lab is not accredited for that function, it does not mean they cannot calibrate it just that they chose not to publish it on their scope for various reasons.
If you have any questions regarding this or any other of your calibration needs give us a call here at Angels, we’ll be more than happy to help!