• 센서학회지
• /
• 제10권1호
• /
• pp.24-32
• /
• 2001

합성사파이어 단결정을 센서틀, 절연디스크 및 보호관으로 사용한 새로운 형태의 고온백금저항온도계를 설계, 제작하고 그 특성을 조사하였다. 제작된 온도계를 고정점에서 시험한 결과 국제온도눈금 (ITS-90)에서 규정한 내삽계기용 고온백금저항온도계의 조건을 만족하였으며, $500^{\circ}{\sim}1500^{\circ}C$영역에서 2차식의 온도-저항특성을 보였다. 구리응고점에서의 재현성 측정결과 ${\pm}19.2\;mK$이었다. 온도계의 절연저항은 온도가 상승함에 따라 지수함수적으로 급격히 감소하였으며, 시험최고온도인 $1500^{\circ}C$에서는 $63\;k{\Omega}({\sim}31.5\;mK)$을 보였다.

• 센서학회지
• /
• 제9권3호
• /
• pp.153-162
• /
• 2000

평형수소 삼중점 (13.8033 K)부터 물의 삼중점 (273.16 K) 온도영역에서 표준온도계로 사용되는 캡슐형 백금저항온도계를 일차 교정하려면 고순도 물질의 삼중점이 사용된다. 국제온도눈금-1990 (ITS-90)을 확립하기 위해 평형수소, 네온, 산소, 아르곤, 수은 및 물의 삼중점 중에서 평형수소의 삼중점을 제외한 5 개의 삼중점을 실현하였다. 각각의 삼중점에서 국제비교용으로 채택된 캡슐형 백금저항온도계 2대의 저항을 2회 반복하여 측정하였다. 측정된 삼중점에서의 합성표준불확도는 A형 불확도와 B형 불확도 평가방법을 고려하여 산출하였다. 한국표준과학연구원에서 ITS-90에 정의된 네온, 산소, 아르곤, 수은 및 물의 삼중점에서의 합성표준불확도 추정결과는 각각 0.18 mK, 0.14 mK, 0.14 mK, 0.24 mK 및 0.11 mK 이었다.

• 한국정밀공학회지
• /
• 제26권11호
• /
• pp.41-46
• /
• 2009

We present experimental data on the time response behavior of industrial platinum resistance thermometers (IPRT) to help with the selection of proper sensors in industry and research laboratories. Time constants of IPRTs were measured using a method specified in ASTM standards. Two different sensors of different protecting sheath diameters were tested in air, water and silicon oil at temperatures from $0^{\circ}C$ to $200^{\circ}C$. The time constant was the smallest in water and the highest in air. As the test temperature increased, time constants tended to decrease at all heat conducting media. For different diameters of sheath of IPRT at the same temperature, it was found that the IPRT of larger diameter showed higher time constant in air, but the opposite dependence was observed in water and oil. From the measured results, it was suggested that the sensor diameter and heat conducting medium should be considered if one wants to select proper thermometer to measure the dynamic temperature change in industry and research area.

• 센서학회지
• /
• 제6권2호
• /
• pp.81-86
• /
• 1997

DC 마그네트론 스퍼터링을 이용하여 측온저항체 온도센서용 백금박막을 $Al_{2}O_{3}$ 기판위에 증착시켰다. 열처리 온도, 시간이 증가할수록 박막의 비저항 및 면저항은 감소하였다. Lift-off 방법을 이용하여 $Al_{2}O_{3}$ 기판위에 백금 저항체를 만들었으며, 텅스텐 wire, 실버 에폭시 그리고 SOG를 이용하여 백금박막 측온저항체 온도센서를 제작하였다. $25{\sim}400^{\circ}C$의 온도범위에서 백금박막 측온저항체 온도센서의 저항온도계수와 저항 변화율을 조사한 결과, 열처리 온도, 시간 및 박막의 두께가 증가할수록 저항온도계수가 증가하였으며 측정 온도범위 내에서 저항값은 선형적인 변화를 보였다. 열처리 온도 $1000^{\circ}C$, 시간 240분 그리고 박막두께 $1{\mu}m$ 조건에서 백금의 벌크에 가까운 $3825ppm/^{\circ}C$의 저항온도계수값을 얻을 수 있었다.

• 센서학회지
• /
• 제21권2호
• /
• pp.109-113
• /
• 2012

We propose an improved interpolating equation to express temperature-resistance characteristics for modern industrial platinum resistance thermometers (PRTs). Callendar-van Dusen equation which has been widely used for platinum resistance thermometer fails to fully describe temperature characteristics of high quality PRTs and leaves systematic residual when the calibration point include temperatures above $300^{\circ}C$. Expanding Callendar-van Dusen to higher-order polynomial drastically improves the uncertainty of the fitting even with reduced degrees of freedom of the fitting. We found that in the fourth-order polynomial fitting, the third-order and fourth-order coefficients have a strong correlation. Using the correlation, we suggest an improved interpolating equation in the form of fourth-order polynomial, but with three fitting parameters. Applying this interpolating equation reduced the uncertainty of the fitting to 32 % of that resulted from the traditional Callendar-van Dusen. This improvement was better than that from a simple third-order polynomial despite that the degrees of the freedom of the fitting was the same.

• 센서학회지
• /
• 제22권6호
• /
• pp.415-420
• /
• 2013

Calibration capabilities for thermometer calibration by comparison method were assessed using high-precision industrial platinum resistance thermometers (IPRT). It was found in the performance assessment that out of 31 laboratories who participated, 28 laboratories resulted magnitude of En number less than 1 at every calibration points they submitted results in the range from 50 to $500^{\circ}C$. The results of about 75% of the laboratories showed the difference from the assigned values less than 1/10 of the tolerance level of the class B IPRT. This indicates that the participating calibration laboratories performed with satisfactory level that was enough to calibrate IPRTs to significant precision. The sensors used in this work were manufactured and chosen by the criteria of long-term instability less than 4 mK and hysteresis less than 8 mK in the temperature range used in this work. Furthermore, the change in the resistance of the sensors in the calibration temperature range were less than the uncertainty of the calibration, 25 mK (k=2).

• 센서학회지
• /
• 제18권1호
• /
• pp.86-94
• /
• 2009

Temperature measurement capability was inter-compared using the transfer standard platinum resistance thermometers(SPRT) among four laboratories of KRISS. The transfer SPRTs were primarily calibrated at the triple point of water and Ga melting point, then used at inter-comparison experiment. Temperature difference of calibration value between temperature laboratory and length laboratory at $20^{\circ}C$ was -0.7 mK and +2.4 mK at density laboratory. Temperature measured near $20^{\circ}C$, $25^{\circ}C$ and $30^{\circ}C$ at fluid flow laboratory was deviated by $34.2{\sim}80.4\;mK$ from the calibration values of the transfer SPRT. Ga melting points was inter-compared among three laboratories, and the difference of Ga melting points against the standard Ga melting point of temperature laboratory were $0.03{\sim}0.54\;mK$ at length laboratory and 0.02 mK at density laboratory.

• 센서학회지
• /
• 제13권6호
• /
• pp.411-416
• /
• 2004

In the international temperature scale of 1990 (ITS-90), standard platinum resistance thermometer (SPRT) is a defining standard thermometer used in the temperature range from 13.8033 K to $961^{\circ}C$. Uncertainty of SPRT is about several mK and uncertainty of defining fixed points of the ITS-90 which is used for calibrating SPRT is about several tenth of mK. Above $0^{\circ}C$. the defining fixed points are gallium melting point and indium, tin, zinc, aluminium and silver freezing points which are all realized using an electric furnace or a liquid bath. To realize freezing point of tin ($231.928^{\circ}C$) and zinc ($419.527^{\cir}C$), two 3-zone furnaces which have 3 electric heaters were manufactured. Temperature gradient of the constructed furnaces were tested. Uncertainty caused by temperature gradient of furnace and immersion effect of SPRT in the sealed-type freezing point cells were evaluated 0.038 mK for tin freezing point and 0.036 mK for zinc freezing point.