Pt100 platinum resistance: how to correctly use standard platinum resistance thermometer?

　　pt100 platinum resistance:The standard platinum platinum resistance thermometer is a precision measuring instrument that measures temperature based on the characteristics of the resistance value of metal platinum that changes with temperature. It consists of a temperature sensing element composed of platinum wire, an insulating skeleton, a protective sleeve and a wire. The molybdenum wire wound on the skeleton adopts a stress-free structure, so that the temperature-sensitive platinum wire can freely expand and contract when the temperature changes. Under the action of external force, such as vibration and improper operation of transporting goods, the platinum wire will deform. Each part of the platinum wire is stressed. When the temperature is above 0.01 °, the resistance value of the platinum wire will increase, and the deformed platinum wire is in a stable state. Therefore, deformation and stress are important factors that lead to the instability of the resistance value of the standard platinum resistance thermometer.

There are no international regulations on how to properly use and maintain standard platinum resistance thermometers. According to decades of production experience and a large number of reference data, it is important to make the platinum wire temperature sensing element in a stress-free state as much as possible, and try to maintain this state in the future.
1. Standardsplatinum resistanceThe thermometer shall be stored in a special box equipped with thermometer when leaving the factory. When taking out or putting in, hold the thermometer handle with your right hand and the lead wire with your left hand to avoid shaking. Severe shaking will produce stress on the platinum wire, causing the change of Rtp resistance value. Regardless of whether any temperature measurement medium is inserted, first wipe the thermometer several times with an alcohol cotton ball. After cooling, slowly insert the thermometer into the measured medium. 2. When inserting the standard platinum resistance thermometer into the zinc point furnace, first insert the thermometer into the 420 ° annealing furnace for preheating, then slowly insert the thermometer into the zinc point furnace, and start measuring after reaching thermal equilibrium. The purpose of this operation is to protect the thermometer and make the zinc solidification temperature plateau flatter and longer. When the standard platinum resistance thermometer is measured in a water triple point bottle, the thermometer at room temperature should be pre-cooled in a pre-cooling tube for 5-10 minutes, and the measurement starts after reaching thermal equilibrium. Note that the current through the standard platinum resistance thermometer during the measurement is 1mA. 3. When using a water tank or fuel tank as the temperature measuring medium, the thermometer should be fixed with a wooden clamp to avoid damage to the thermometer when the water tank is stirred, but the clamp should not be too tight. After measurement, take out the thermometer and wipe it with a soft cloth, especially after the thermometer is used in the fuel tank, otherwise the outer tube of the thermometer will be easily contaminated, the oil on the outer wall of the thermometer will turn black due to annealing, and it will also pollute the annealing furnace and the verification furnace. At -50~0 °: The insertion depth of the standard platinum resistance thermometer should be 150-200mm. When the temperature is higher than 50, the insertion depth of the standard platinum resistance thermometer is 200-300mm. 4, standard platinum resistance thermometer should avoid high temperature quenching. Rapid cooling will damage the thermometer, deform the platinum wire inside the thermometer, generate stress, change the resistance temperature characteristics of the thermometer, and also cause the crystal on the outer tube of the thermometer to absorb, thereby shortening the service life of the thermometer.
The platinum wire of the standard platinum resistance thermometer is slightly deformed, resulting in little change in resistance value. After short-term annealing at an appropriate temperature, the resistance value can be restored to the approximate value before deformation. However, if the large deformation is annealed at a higher temperature for a long time, the resistance value cannot be restored to the value before the deformation. Therefore, the standard platinum resistance thermometer should always check whether the platinum wire is abnormal or sagging during use. In addition, the thermometer should always check the resistance value of the triple point of water. If it is found that the measured resistance value is very different from the value on the certificate, if the standard platinum resistance thermometer is greater than 5mK and the secondary standard platinum resistance thermometer is greater than 10mK, the thermometer should be sent for inspection in advance.
The main products of Jinzhou Jingwei Instrument Co., Ltd. are pt20, intrinsic safety constant power thermal flowmeter, pt100 platinum resistor, constant power thermal flowmeter, pt100, pt100 thermal resistor, platinum resistor, thermal flow sensor, thermal resistor, temperature field calibrator, high precision thermometer, oil and gas recovery flowmeter, thermocouple, temperature transmitter, temperature sensor, etc. It has the ability to produce high-quality, high-precision industrial sensors and instrumentation. At present, the use of our products has reached more than two thousand users. "As long as users of Jinzhou's subtle products will be repeat customers". Our company's aim is "to the quality of development, reputation to win the world". Cooperation units: State-owned 171 Factory, Hangzhou Focus Technology Co., Ltd., China Institute of Metrology, Tianxin Instrument Group Co., Ltd. Since its establishment, our company has been striving for perfection and innovation on the premise of meeting the continuous improvement of product quality requirements of users, and has achieved rapid development. China's products have entered an era of high quality, and we have benefited from this era.