ASTM E77 PDF
E77 – 98 Standard Test Method for Inspection and Verification of Thermometers, Calibration-temperature instrumentation, Liquid-in-glass thermometers. Inspection and Verification of Thermometers, is based on ASTM E77 − 14, Standard. Test Method . E1 Specification for ASTM Liquid-in-Glass Thermometers. Buy ASTM E() Standard Test Method for Inspection and Verification of Thermometers from SAI Global.
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The satm of any change in this reference reading as a result of the h heating period is a measure of the quality of the bulb glass and the adequacy of the previous heat treatment accorded the thermometer in manufacture. If the document is revised or amended, you will be notified by email. Temperatures are not measured directly with this instrument.
Such thermometers should always be inspected for these separations, which can be repaired by the procedures described above. As the voice of the U. The most common types of foreign matter which should be cause for rejection are glass chips, particles of dirt or lint, oxide of mercury aztm red, yellow, or blackproducts of glass weathering commonly astj white deposit, and stones or iron spots traceable to faulty glass fabrication.
Burning out, loosening, chalking, or fading of the aztm shall be cause for rejection. In order that it shall be satisfactory for such use, the thermometer should meet the requirement that the ratio of resistances at the steam and ice points shall be greater than 1. In all cases only the current version of the standard as published by ASTM is to be considered the official document.
Discontinuities in the spacing are evidence of faulty graduating. Please first log in with a verified email before subscribing to alerts.
This standard is not included in any packages. They asmt be completely recalibrated every 6 to 12 months, depending upon the temperatures of usage. Discard any cloudy or unsound portions.
If any portion of the stem containing mercury is exposed, the emergent mercury column correction should be determined. Ice points should be taken every 3 months. We have no amendments or corrections for this standard. Metal block baths and the salt and tin comparator baths, described in Appendix X1, are examples of the type of equipment that has been found to be suitable for this purpose.
By softly tapping on a soft spongy material or against the hand it usually is possible to bring the liquid together in the bulb.
ASTM E77 – 14e1 – Standard Test Method for Inspection and Verification of Thermometers
Already Subscribed to this document. Any stones or striae that distort the bore or asmt appearance should be cause for rejection. Select clear pieces of ice or ice made from distilled or pure water. For fractionally graduated thermometers a calibrated set of r77 following thermometers is recommended. Thermometers that have a contraction chamber below the lowest graduation are likely to develop separations either in the chamber or above it. Return the thermometer to the bath, preheated to the temperature of test, and heat for 24 h.
Successive readings taken a.
Because it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. Need more than one copy? Strains in the glass as observed with a polarized light strain gage near enlargements in the stem or bore, or at the top of the thermometer, are detrimental. If the pigment in the scale etchings washes out or fades, the thermometer will be difficult to read.
It is frequently possible to join such separations by cooling the thermometer so that the separated portion as well as the main column both stand in the chamber. Current edition approved Nov.
It is frequently a good practice to ast only the bulb of the thermometer. Heat the thermometer to the selected reference point on the main scale, maintain the temperature for at least 15 min, and determine the scale correction at this point.
For more stubborn separations it may be necessary to cool the bulb in dry ice to a point low enough to bring all of the liquid into the bulb itself. This astmm has been approved for use by agencies of the Department of Defense. You may delete a document from your Alert Profile at any time.
It is the responsibility of the asym of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Astmm thermometers can be used as standards to calibrate other thermometers similar in all details of construction above the immersion point, but may differ below the immersion point to the extent of including an auxiliary ice point scale.
It is only necessary to have a liquid-in-glass thermometer completely calibrated one time. If natural cooling in still air is used, determine the reference reading within 1 h. Last previous edition approved in as E 77 — Mercury, or its vapor, may be hazardous to health and corrosive to materials. This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version.
Originally published as E 77 — 49 T. This keeps the viscosity of the liquid in the capillary low and aids in hastening drainage.
ASTM E77 – 14e1
It must be emphasized that to obtain meaningful results, the procedure adopted after the h period of heating must be identical to that used in the original calibration. They are simpler to use than a primary standard thermometer with its accessory equipment, the latter being capable of an order of precision and axtm far in excess of that attainable with liquid-in-glass thermometers.
Recalibration is performed as described in 6. Gentle tapping of the thermometer while held upright will cause the bubbles to rise to the surface.
ASTM E77 – 98 Rpdf全文-调研报告-在线文档
If a mercury separation is observed in the stem, several different ways are suggested for joining the columns, depending on the construction of the thermometer and the type of separation. Allow to cool slowly. The choice of a secondary standard will be governed by various factors. A number in parentheses indicates the year of last reapproval. Adjust the dividers to extend over 10 or 20 graduations, and successive intervals can be intercompared rapidly.