temperature and pressure in the svartsengi ... - Orkustofnun

temperature and pressure in the svartsengi ... - Orkustofnun temperature and pressure in the svartsengi ... - Orkustofnun

13.07.2015 Views

;T=1 JHD·HS~·9000 GGL.:J::J 83 .09.1241OutlrHoulin, ----0Support,..St'l'IUI ___ _BULBSund.rdFnl R.spond inlTEMPERATUREELEMENTClrryin,M" dmumR.,illlrln,ThlrmomltlrRECOROING SECTION(GAUGE)PRESSUREELEMENTFig . 9 Cross-sections of Amerada pressure and t emperatureprobes.

293.2 Temperature elementThe bourdon tube in the temperature element is sealed.Variations 1n temperature create different boilingpressure inside the bourdon tube. The vapour pressure ofthe enclosed liquid is directly related to its temperature,making the rotated position of the free end of the bourdontube an usable measure of the temperature of the element.This rotation is recorded on the gauge chart as describedabove.3.3 Limits of accuracyThe repeatabl11ty of a properly maintained gauge is betterthan -0.1 % of full range of the pressure element in use,while the absolute accuracy Is 0 . 2% . Temperatures above70 0 C affect the strength of most Bourdon tubes socalibrations are necessary to maintain the accuracy of theinstrument. The sensitivity of the gauge 1s 0.2% of fullscale deflection.The absolute accuracy of the temperature gauge is usuallyassumed to be 2°C but this is related to the calibrationand operation of the instruments.

293.2 Temperature elementThe bourdon tube <strong>in</strong> <strong>the</strong> <strong>temperature</strong> element is sealed.Variations 1n <strong>temperature</strong> create different boil<strong>in</strong>g<strong>pressure</strong> <strong>in</strong>side <strong>the</strong> bourdon tube. The vapour <strong>pressure</strong> of<strong>the</strong> enclosed liquid is directly related to its <strong>temperature</strong>,mak<strong>in</strong>g <strong>the</strong> rotated position of <strong>the</strong> free end of <strong>the</strong> bourdontube an usable measure of <strong>the</strong> <strong>temperature</strong> of <strong>the</strong> element.This rotation is recorded on <strong>the</strong> gauge chart as describedabove.3.3 Limits of accuracyThe repeatabl11ty of a properly ma<strong>in</strong>ta<strong>in</strong>ed gauge is betterthan -0.1 % of full range of <strong>the</strong> <strong>pressure</strong> element <strong>in</strong> use,while <strong>the</strong> absolute accuracy Is 0 . 2% . Temperatures above70 0 C affect <strong>the</strong> strength of most Bourdon tubes socalibrations are necessary to ma<strong>in</strong>ta<strong>in</strong> <strong>the</strong> accuracy of <strong>the</strong><strong>in</strong>strument. The sensitivity of <strong>the</strong> gauge 1s 0.2% of fullscale deflection.The absolute accuracy of <strong>the</strong> <strong>temperature</strong> gauge is usuallyassumed to be 2°C but this is related to <strong>the</strong> calibration<strong>and</strong> operation of <strong>the</strong> <strong>in</strong>struments.

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