At 03:18 PM 2/14/02 -0600, Pete wrote:
>Ken,
>
>You are absolutely right. They are a sealed device like a precision glass
>thermometer. As long as the glass is not chipped or broken, there is no
>need for checking calibration.
1. Precision glass thermometers do require periodic calibration. They both
age slowly (over years) and level-shift due to temperature stresses in use.
2. A hydrometer normally doesn't change during use, since this is based on
only weight and volume and could not conceivably change enough to affect a CCP.
3. It is only prudent to check every monitoring device on some schedule,
even if it appears unnecessary. Checking a hydrometer with a standard salt
solution is almost trivial. A crack is a clear mode of failure in a hydrometer.
================================================================
Robert A. LaBudde, PhD, PAS, Dpl. ACAFS e-mail: ral@lcfltd.com
Least Cost Formulations, Ltd. URL: http://lcfltd.com/
824 Timberlake Drive Tel: 757-467-0954
Virginia Beach, VA 23464-3239 Fax: 757-467-2947
"Vere scire est per causas scire"
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