Why Verify Temperature?
Performing a test or running a process at the incorrect temperature is a frequent source of bad results. Variability of temperature either in accuracy or uniformity is a significant, and often unrecognized, contributor to reduced quality in products and inconsistency in test data. Verification of temperature measuring systems is often not done frequently enough or with appropriate procedures and proper methodologies. To address this problem, Instron®
has developed a number of temperature verification procedures that meet the most common requirements of laboratories and related manufacturing processes. These procedures are fully compliant with ISO/IEC 17025, and when performed, provide assurance that your test data is valid, and your processes are properly controlled.
Examples of typical equipment that we verify:
- Environmental chambers and furnaces manufactured by Instron®, SFL, and most other brands
- Temperature profiles to characterize gradients, including oven and chamber uniformity surveys
- Temperature data loggers, circular or strip chart recorders
- Temperature indicators of all types
- Heat treating and finishing equipment
- All types of testing equipment that utilize temperature control
- Temperature controls for various manufacturing processes
Instron performs two types of temperature verifications in the field. Type 1 is referred to as “in-situ” and is performed by placing a calibrated thermocouple(s) right next to the temperature that is to be verified and comparing its reading to the system's reading. Type 2 is “sensor substitution” and consists of injecting calibrated signals into the instrument being verified. This simulates a correctly performing thermocouple (mV) or RTD (ohms). Type 1 is preferred because the entire system is verified. Type 2 verifies the electronics only and is used when Type 1 is not possible or practical. Often an in-situ (Type 1) verification will be done at one temperature (the current temperature of a process, for example,) then a sensor substitution verification (Type 2) will be performed on the electronics to ensure they are operating properly throughout their range. Note that many calibration vendors only perform Type 2 verifications.
Type 1: - 200 to +900° C (-30 to +500° C in Europe)
(Expanded Uncertainty approximately 1°
in the -200 to 300 range, and increasing at higher temperatures)
Type 2: - 200 to +1800° C
(Expanded Uncertainty approximately 1 to 2°, depending on thermocouple type and temperature)
How Can I Improve the Management of My Lab's Calibration Program?
We store all relevant information about your equipment and site in our database. That allows us to keep track of recalibration dates (specified by you), so we can call ahead of time, and schedule convenient and timely recalibrations. When the verification is complete, the Instron engineer can print the certificate and data report on-site before he leaves. The data and certificate are electronically backed up in a secure database at the Instron factory and can be retrieved, if necessary.