低温压力传感器校准系统研制与应用

介绍了一种用于低温压力传感器校准装置,该装置能在试验室对低温压力传感器进行校准,可满足压力传感器复杂低温环境的要求,准确、客观地反映低温压力传感器的性能指标,具有较高的测量精确度.利用该校正装置在20 K、77 K条件下成功对某压力传感器进行标定,证明此套校验装置的有效性和可靠性.     

液氧煤油发动机地面试验低温压力传感器校准系统设计

为获得不同环境温度下低温压力传感器的校准系数,提高压力测量的精度,着重介绍低温压力传感器校准系统设计,该校准系统具备温度自适应调整功能,为低温压力传感器校准提供温区连续、大范围温度可控的温度环境以及稳定可调的压力源,在一定程度上消除温度环境因素对传感器灵敏度的影响。通过低温压力传感器现场校准测试,获得压力传感器在不同温度环境下的工作特性并掌握其随温度变化的规律。     

用于低温压力传感器校准的低温工作环境的研制

针对航天液体发动机试验用低温压力传感器的真实工况下校准等问题,设计了用于低温压力传感器校准的低温工作环境装置。该装置采用PID控制技术和低温、高压、真空耦合环境密封技术,可以提供温度可控、温区连续、超大温度范围的低温环境(-196～20℃)。实验结果表明,该环境装置能够达到设计要求,可同时对多个低温压力传感器校准。     

低温离心机温度参数校准

低温离心机是核酸检测实验室基本的仪器,主要用于血液离心和DNA、RNA样品核酸提取.低温离心机的温度控制性能,是离心萃取和样本裂解的关键参数,其温度参数直接影响实验室检测结果的可靠性.在使用低温离心机之前,对低温离心机的进行温度校准,是保证实验室试验结果准确的重要环节.采用有线温度巡检仪校准方法是在离心机腔底部离转子较近处设温度传感器,通过测量离心腔底部空气温度间接测量转子内试样所处腔内温度,这种方法无法准确地测量离心过程中的试样所处腔内温度变化,测试结果误差大、准确度低.通过无线温度验证系统,配以精准的布点方式,可以准确测量离心机运转时的温度参数.     

压力传感器动态特性实验研究

通过对压力传感器循环寿命试验前后动态特性的测试和分析,用实验方法研究了压力传感器动态特性变化。结果表明,循环寿命试验前后,压力传感器的静态特性基本保持不变,而动态特性却发生了较大变化。因此,对用于动态压力测试的传感器进行定期动态特性校准非常必要;对用于高频、高周次动态压力测试的传感器,在实际使用前进行循环老化试验可以提高动态压力测量结果的准确性。     

试飞测试系统压力参数在线校准方法与装置

当前试飞测试系统压力参数的校准主要采取拆卸后在实验室校准的方式,存在校准时间长,多次拆装容易造成接口损坏的问题。为了解决这个问题,研究一种压力参数的在线校准方法,实现了真实工况下的原位比对校准。通过实验获得了标准压力传感器在温度复合情况下的量值特性规律,构建了温度补偿模型,实现了标准压力值的准确获取。研制了由三个不同量程标准压力传感器、环境温湿度和大气压传感器以及在线校准软件等组成的校准装置,通过初步实验验证了校准方法和装置的合理性。该方法可以作为实验室校准的有效补充,降低校准的人力和时间成本,提高飞行试验的效率。     

ConST980压力传感器测试筛选系统的研究和应用

文章给出一种压力传感器测试筛选系统,该系统包含压力传感器测试装置、数据采集分析系统、综合控制器、气源发生器,通过对压力传感器在不同温度下数据的自动分析,实现压力传感器的在线老化、分级筛选和标定,从而达到压力传感器全自动的校准和检定目的。     

基于低温制冷机的低温流体电容式密度测量

设计并搭建了一套基于G-M低温制冷机的电容式密度测量实验装置,由平行板电容器、样品流体测试腔、充排气体管路、低温制冷机、温度测量与控制单元、压力测量单元、真空绝热保护腔以及高真空排气系统八个部分组成。该系统适用温度测量范围为15—300 K,压力测量范围0.01—0.3 MPa。实验中的低温液体由常温气体经低温制冷机冷却液化得到,并蓄存在装有平行板电容器的样品测试腔内。该测试腔上开有视窗,可用于观察冷却过程中低温液体的形成及其液位。对受控压力及温度下的液氮、液氩两种低温流体的密度进行了测量,所得数据与文献实验值及美国NIST标准数据吻合良好,液相区相对偏差小于±0.5%。该密度测量系统今后可用于测量其他流体(包括混合物)在低温下的p-ρ-T数据,还有望经过改进和集成化设计后实现LNG和空分等工业领域的低温流体密度在线实时监测。     

可拆卸恒温腔头温度源装置的研究

介绍了烙铁温度计的基本原理、用途及其校准装置的工作原理、基本结构和控制结构,采用模拟烙铁焊嘴的恒温腔结构,以提供恒定温度源。以Ⅰ级K型热电偶作温度传感器,采用内加热方式,按PID控制方式对恒温腔温度进行精密测量与控制,实验结果表明,装置的温度准确度达到了0.1级,满足校准常见烙铁温度计的要求。     

温度变送器(带传感器)现场检测影响因素探讨

文章针对温度变送器(带传感器)现场校准的影响因素,从恒温设备的温场、校准环境条件和感温端插入温场深度等方面进行实验室校准和现场校准试验,通过试验获取数据并进行分析,提出了温度变送器(带传感器)现场校准合适的环境条件、感温端插入温场深度的要求和恒温设备温场介质选择,为温度变送器(带传感器)现场校准提供了依据和参考,有利于提高温度变送器(带传感器)现场校准的准确度和可靠性。     

薄膜光电性能表征用小型液氮低温恒温器

本文介绍了一种高真空低温环境下用于薄膜光电性能研究的小型液氮低温恒温器,它能提供稳定低温并与外界隔绝的真空环境,可广泛用于薄膜材料的光学、磁热、超导和电学性能研究领域.系统通过液氮杜瓦和基片加热装置使样品维持在所需的低温高真空条件下,既能通过外接光源将光线引入真空室并辐照在样品上或通过真空电极引线测试样品的电学特性,也可实现薄膜的光电性能表征.热负荷计算与分析表明,该系统可长时间保持所需的低温真空环境,且该装置具有结构简单、体积小和温控稳定等优点,适于薄膜器件的真空低温变温研究.     

Top Loading Cryogen Free Cryostat for Low Temperature Sample Environment

Today almost a quarter of all neutron scattering experiments performed at neutron scattering facilities require sample temperatures below 2 K. However, a global shortage of helium gas can seriously jeopardise low temperature experimental programmes at neutron scattering laboratories. Luckily the progress in cryo-cooler technology offers a new generation of cryogenic systems with significantly reduced consumption and in some cases nearly a complete elimination of cryogens. Here we discuss design and test results of a new cryogen free top-loading cryostat developed through an ISIS and Oxford Instruments collaborative project. The cryostat provides neutron scattering sample environment in the temperature range 1.4–300 K. High cooling power (0.23 W at temperature less than 2 K) achieved at the cryostat’s variable temperature insert heat exchanger allows operation of a standard dilution refrigerator insert in a continuous regime. From a user perspective, the system offers operating parameters very similar to those of an Orange cryostat but without the complication of cryogens.     

Characteristics of a silicon pressure sensor in superfluid helium pressurized up to 1.5 MPa

It is known that a piezo-resistive pressure sensor, FPS-51B manufactured by Fujikura Ltd., is available for in situ pressure measurement in superfluid helium. The sensor covers a pressure range of zero to 103.4 kPa. The maximum rated pressure is 202.6 kPa at room temperature. The characteristics of the pressure sensor in a pressure range up to approximately 0.2 MPa were reported in detail for use in superfluid helium. We measured the pressure characteristics of this sensor up to 1.5 MPa to determine its availability to be used under much higher pressure. Measurements were taken using a cryostat, which can be pressurized up to 1.5 MPa at room temperature and superfluid helium temperatures. It was found that the sensor could be used in a superfluid helium environment at pressures up to 1.5 MPa, without any damage and with good reproducibility.     

Simple dipstick cryostat with versatile temperature controller for high thermal stability

A simple dipstick type vapour cryostat and a versatile electronic temperature controller which uses a proportional, integral and differential type of control are described. They have been used together for the calibration of thermometers in the liquid helium temperature range and for the measurement of the transition temperature of superconductors. Temperature stability of 2 mK (typical) is achieved easily at a working temperature of 7 K for a period exceeding an hour. The use of the system is quite general and can readily cover the temperature range up to 300 K with a suitable choice of temperature sensor and heat input.     

A simple inexpensive cryostat for measurement of Mossbauer spectra from 77 K to 300 K

A simple continuous flow cryostat designed for Mossbauer investigations with liquid nitrogen in the temperature range 77–300 K is described. The cryostat is built with a perspex sample holder, glass tubes and metallic frames for mylar windows which facilitate transmission of gamma rays. A copper - constantan thermocouple is used as the temperature sensor. The cryostat can be used in investigations where either the absorber or the source is at rest and the detector-absorber - source axis is horizontal. The performance of the unit is tested on low-temperature studies of stainless steel.     

A closed cycle helium cooled cryostat

The design of a low temperature cryostat suitable for accelerator based radiation damage studies is presented. The system employs a commercial two-stage closed cycle helium gas cryorefrigerator and a mechanical heat switch to permit sample irradiations at 13–15 K and rapid temperatures cycling up to 300 K for post irradiation isochronal anneal studies. Al-In and Al-Ag switch contacts are evaluated for the cryostat.     

A vibration free cryostat using pulse tube cryocooler

This paper introduces a new vibration free cryostat cooled by liquid helium and a 4 K pulse tube cryocooler. The cryogenic device mounts on the sample cooling station which is cooled by liquid helium. The boil off helium is recondensed by the pulse tube cryocooler, thus the cryostat maintains zero boil off. There is no mechanical contact between the cryogenic part of the cryocooler and the sample cooling station. A bellows is used to isolate the vibration which could transfer from the cryocooler flange to the cryostat flange at the room temperature. Any vibrations generated by the operation of the cryocooler are almost entirely isolated from the cryogenic device. The cryostat provides a cooling capacity of 0.65 W at 4.21 K on the sample cooling station while maintaining a vapor pressure of 102 kPa. The sample cooling station has a very stable temperature with oscillations of less than ±3 mK during all the operations. A cryogenic microwave oscillator has been successfully cooled and operated with the cryostat.