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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If the pigment in the scale etchings washes out or fades, the thermometer will be difficult to read. Already Subscribed to this document.
Secondary standards may be of the following types. Caution should be taken when handling mercury and mercury containing products. Scale corrections should always be applied in the use of these standards. This is due to the effect of increased gas pressure above the column producing a distortion of the bulb. If any portion of the stem containing mercury is exposed, the emergent mercury column correction should be determined. A slight tapping of the 4 E 77 — 98 thermometer against the palm of the hand will facilitate this joining.
ASTM E77 – 98 Rpdf全文-调研报告-在线文档
Standards Subsctiption may be the perfect solution. In the case of diameter measurements, the bulb or other portions of the thermometer being tested should not enter the smaller of the holes in the ring gage see 5. If natural cooling is used, the correction should be determined within 1 h.
Tapping the tube against the hand or the bulb on a soft spongy material, such as a rubber stopper, usually will bring the liquid together. If such globules appear to unite and then reappear on cooling the bulb, they are indicative of oxidation of the mercury or the presence of obstructions in the bore, and should result in rejection of the thermometer.
Normally, the effect of taper in the capillary or nonlinearity in the expansion characteristics of organic liquids is manifested by a gradual change in the spacing of the graduations. The choice of a secondary standard will be governed by various factors. Allow the thermometer to cool, at the same rate as at the start of the test, to the temperature referred to above, and redetermine the reference reading under the same conditions as before.
More complete information on the construction and use of primary standard thermometers may be obtained from NIST SP The change in ice-point reading should then be applied to all readings. Last previous edition approved in as E 77 — Inspect the thermometer for differences in appearance of the tested and untested sections of the scale portion.
Its electrical resistance is determined by comparison with a standard resistor, using a potentiometer, a Kelvin-type double bridge, or a Wheatstone bridge, preferably of the Mueller type or an AC resistance bridge.
If bubbles are observed in the bulb, they can generally be removed by cooling the bulb with dry ice or other convenient coolant until all the liquid is drawn into the bulb. Successive readings taken a.
Please first verify your email before subscribing to alerts. Organic liquids as used in thermometers, in contrast to mercury, wet the glass.
Proceed to Checkout Continue Shopping. Suitable types are described in Appendix X1. Standards Subscriptions from ANSI provides a money-saving, multi-user solution for accessing standards. These 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 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. In some instances total-immersion thermometers may be used under conditions of complete immersion. Discard any cloudy or unsound portions. The liquid should emerge into the bore with no separation. 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.
When the column itself follows into the chamber, the separated portion usually will join onto the main column. This standard is not included in any packages.
Temperatures may then be calculated using suitable resistance- temperature equations. Because it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate.
In reading thermometers, account must be taken of the fact that the lines are of appreciable width. 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.
Improper annealing of the bulb, as determined by the bulb stability test, will result in thermometer readings rapidly changing with time and use. By softly tapping on a soft spongy material or against the hand it usually is possible to bring the liquid together in the bulb.
In all cases only the current version of the standard as published by ASTM is to be considered the official document. Burning out, loosening, chalking, or fading of the pigment shall be cause for rejection. The thickness of such gages should approximate the diameters of the holes to minimize errors resulting from the axis of the thermometer stem being other than normal to the plane of the gage.
ASTM E77 – 07 Standard Test Method for Inspection and Verification of Thermometers
It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
You may delete a document from your Alert Profile at any time. A number in parentheses indicates the year of last reapproval. If natural cooling in still air is used, determine the reference reading within 1 h.
ASTM E77 – 14e1
We have no amendments or corrections for this standard. Return the thermometer to the bath, preheated to the temperature of test, and heat for 24 h.
Select clear pieces of ice or ice made from distilled or pure water.