推荐 检测技术实验指导书.docx

1、推荐 检测技术实验指导书实验六工业热电偶的校验一实验目的1了解热电偶的工作原理、构造及使用方法。了解热电势与热端温度的关系。了解对热电偶进行校正的原因及校正方法，能独立地进行校正实验和绘制校正曲线。2了解冷端温度对测量的影响及补偿导线的使用方法。3通过测量热电势掌握携带式直流电位差计的使用方法。二实验设备1铂铑铂热电偶（标准热电偶）支镍铬镍硅热电偶（被校正热电偶） 支3热电偶卧式检定炉（附温度控制器） 台4携带式直流电位差计 1台5酒精温度计 1支6广口保温瓶 1个7热浴杯及酒精灯 各1个三实验内容与步骤了解直流电位差计各旋钮、开关及检流计的作用，掌握直流电位差计的使用方法。热电偶校正（）实验

2、开始，给检定炉供电，炉温给定值为400C。当炉温稳定后，用电位差计分别测量标准热电偶和被校正热电偶的热电势，每个校正点的测量不得少于四次。数据记录于表6。（）依次校正600C、 800C、 1000C各点。（）将测量电势求取平均值并转换成温度，计算误差，根据表6判断被热电偶是否合格。绘制校验曲线。表6热电偶校正 （温度：C，电势mV）标准热电偶S被校热电偶K测量电势mV温度测量电势mV温度误差热电偶冷端温度对测温的影响及补偿导线的使用方法。（）1000C校正点作完后，保持炉温不变。测量热浴杯中的水温，然后用电位差计分别测量镍铬镍硅热电偶未加补偿导线和加补偿导线的热电势。数据记录于表6中。（）用

3、酒精灯加热热浴杯，当水温依次为30C、 40C、 50C时，用电位差计分别测量镍铬镍硅热电偶未加补偿导线和加补偿导线的热电势。数据记录于表6中。（）用铂铑铂热电偶测量炉温，检查实验过程中炉温是否稳定，分析若炉温变化对实验的影响。（）将测量电势转换为温度，绘制热电偶冷端温度对测量影响曲线。表6热电偶冷端温度对测量影响水浴温度C加补偿导线未加补偿导线误差C测量电势 mV温度 C测量电势 mV温度 C四思考题1 控制系统的炉温误差对热电偶的校验影响严重吗？为什么?2 热电偶的补偿导线有无极性？交换顺序后对读数有无影响？3 热电偶的两根补偿导线所处的温度不同，对读数有何影响？例如用手指捏住其中一根导线

4、的中部；同时捏住两根导线的中部；捏住单根补偿导线与热偶丝的接点处；补偿导线与电位差计连接的接线柱处。各有何现象？分析原因。这里是以手指作为热干扰源，应注意绝缘以避免成为噪声干扰源。 五、实验报告内容及要求见附录。附一：热电偶校正实验装置介绍热电偶在长期使用过程中，热电极和热接点容易受到氧化、污染和腐蚀。高温下热电极材料容易发生再结晶而劣化，因此热电偶的热电特性会逐渐发生变化。使用中会增加测量误差。为了保证热电偶的测量精度，必须进行定期校验。对于各种不同热电偶校正点温度及校正允许偏差都有规定，如表6所示。表6工业热电偶允许误差范围热电偶名称分度号使用温度范围允许误差铂铑铂S0600C1.5C60

5、01600C0.25%t镍铬镍硅K0400C3C4001300C0.75%t工业和实验室用热电偶都把管状电炉作为校正的基本装置。把标准热电偶和被校正热电偶的工作端放入管状电炉的中心处，使它们处于同一温度环境中。然后比较两者的电势值，以确定被校正热电偶的误差等指标。这种方法称为比较法。实验装置如图所示。主要有管状电炉、温度控制系统、直流电位差计、标准热电偶和冰点槽等。图6热电偶校正实验装置温度调节器；热电偶检定炉；标准热电偶（）；被检热电偶（）；补偿导线；补偿导线；冰点槽；热浴杯；电位差计；10铜导线；11酒精灯温度控制系统由SR90系列PID温度调节器、测温热电偶等组成。它为校正热电偶提供一个

6、比较稳定的温度。温度调节器的使用说明如下。附二：热电偶分度表铂铑10铂热电偶分度表分度号：S （参考端温度为）温度0123456789热 电 动势mV-50-0.236-40-0.194-0.199-0.203-0.207-0.211-0.215-0.220-0.224-0.228-0.232-30-0.150-0.155-0.159-0.164-0.168-0.173-0.177-0.181-0.186-0.190-20-0.103-0.108-0.112-0.117-0.122-0.127-0.132-0.136-0.141-0.145-10-0.053-0.058-0.063-0.068

7、-0.073-0.078-0.083-0.088-0.093-0.0980-0.000-0.005-0.011-0.016-0.021-0.027-0.032-0.037-0.042-0.04800.0000.0050.0110.0160.0220.0270.0330.0380.0440.050100.0550.0610.0670.0720.0780.0840.0900.0950.1010.107200.1130.1190.1250.1310.1370.1420.1480.1540.1610.167300.1730.1790.1850.1910.1970.2030.2100.2160.2220

8、.228400.2350.2410.2470.2540.2600.2660.2730.2790.2860.292500.2990.3050.3120.3180.3250.3310.3380.3450.3510.358600.3650.3710.3780.3850.3910.3980.4050.4120.4190.425700.4320.4390.4460.4530.4600.4670.4740.4810.4880.495800.5020.5090.5160.5230.5300.5370.5440.5510.5580.566900.5730.5800.5870.5940.6020.6090.61

9、60.6230.6310.6381000.6450.6530.6600.6670.6750.6820.6900.6970.7040.7121100.7190.7270.7340.7420.7490.7570.7640.7720.7800.7871200.7950.8020.8100.8180.8250.8330.8410.8480.8560.8641300.8720.8790.8870.8950.9030.9100.9180.9260.93409.421400.9500.9570.9650.9730.9810.9890.9971.0051.0131.0211501.0291.0371.0451

10、.0531.0611.0691.0771.0851.0931.1011601.1091.1171.1251.1331.1411.1581.1681.1661.1741.1821701.1901.1981.2071.2151.2231.2311.2401.2481.2561.2641801.2731.2811.2891.2971.3061.3141.3221.3311.3391.3471901.3561.3641.3731.3811.3891.3981.4061.4151.4231.432温度0123456789热 电 动势mV2001.4401.4481.4571.4651.4741.4821

11、.4911.4991.5081.5162101.5251.5341.5421.5511.5591.5681.5761.5851.5941.6022201.6111.6201.6281.6371.6451.6541.6631.6711.6801.6892301.6981.7061.7151.7241.7321.7411.7501.7591.7671.7762401.7851.7941.8021.8111.8201.8291.8381.8461.8551.8642501.8731.8821.8911.8991.9081.9171.9261.9351.9441.9532601.9621.9711.9

12、791.9881.9972.0062.0152.0242.0332.0422702.0512.0602.0692.0782.0872.0962.1052.1142.1232.1322802.1412.1502.1592.1682.1772.1862.1952.2042.2132.2222902.2322.2412.2502.2592.2682.2772.2862.2952.3042.3143002.3232.3322.3412.3502.3592.3682.3782.3872.3962.4053102.4142.4242.4332.4422.4512.4602.4702.4792.4882.4

13、973202.5062.5162.5252.5342.5432.5532.5622.5712.5812.5903302.5992.6082.6182.6272.6362.6462.6552.6642.6742.6833402.6922.7022.7112.7202.7302.7392.7482.7582.7672.7763502.7862.7952.8052.8142.8232.8332.8422.8522.8612.8703602.8802.8892.8992.9082.9172.9272.9362.9462.9552.9653702.9742.9842.9933.0033.0123.022

14、3.0313.0413.0503.0593803.0693.0783.0883.0973.1073.1173.1263.1363.1453.1553903.1643.1743.1833.1933.2023.2123.2213.2313.2413.2504003.2603.2693.2793.2883.2983.3083.3173.3273.3363.3464103.3563.3653.3753.3843.3943.4043.4133.4233.4333.4424203.4523.4623.4713.4813.4913.5003.5103.5203.5293.5394303.5493.5583.

15、5683.5783.5873.5973.6073.6163.6263.6364403.6453.6553.6653.6753.6843.6943.7043.7143.7233.7334503.7433.7523.7623.7723.7823.7913.8013.8113.8213.8314603.8403.8503.8603.8703.8793.8893.8993.9093.9193.9284703.9383.9483.9583.9683.9773.9873.9974.0074.0174.0274804.0364.0464.0564.0664.0764.0864.0954.1054.1154.

16、1254904.1354.1454.1554.1644.1744.1844.1944.2044.2144.224温度0123456789热 电 动势mV5004.2344.2434.2534.2634.2734.2834.2934.3034.3134.3235104.3334.3434.3524.3624.3724.3824.3924.4024.4124.4225204.4324.4424.4524.4624.4724.4824.4924.5024.5124.5225304.5324.5424.5524.5624.5724.5824.5924.6024.6124.6225404.6324064

17、24.6524.6624.6724.6824.6924.7024.7124.7225504.7324.7424.7524.7624.7724.7824.7924.8024.8124.8225604.8324.8424.8524.8624.8734.8834.8934.9034.9134.9235704.9334.9434.9534.9634.9734.9844.9945.0045.0145.0245805.0345.0445.0545.0655.0755.0855.0955.1055.1155.1255905.1365.1465.1565.1665.1765.1865.1975.2075.21

18、75.2276005.2375.2475.2585.2685.2785.2885.2985.3095.3195.3296105.3395.3505.3605.3705.3805.3915.4015.4115.4215.4316205.4425.4525.4625.4735.4835.4935.5035.5145.5245.5346305.5445.5555.5655.5755.5865.5965.6065.6175.6275.6376405.6485.6585.6685.6795.6895.7005.7105.7205.7315.7416505.7515.7625.7725.7825.7935

19、.8035.8145.8245.8345.8456605.8555.8665.8765.8875.8975.9075.9185.9285.9395.9496705.9605.9705.9805.9916.0016.0126.0226.0336.0436.0546806.0646.0756.0856.0966.1066.11176.1276.1386.1486.1596906.1696.1806.1906.2016.2116.2226.2326.2436.2536.2647006.2746.2856.2956.3066.3166.3276.3386.3486.3596.3697106.3806.

20、3906.4016.4126.4226.4336.4436.4546.4656.4757206.4866.4966.5076.5186.5286.5396.5496.5606.5716.5817306.5926.6036.6136.6246.6356.6456.6566.6676.6776.6887406.6996.7096.7206.7316.7416.7526.7636.7736.7846.7957506.8056.8166.8276.8386.8486.8596.8706.8806.8916.9027606.9136.9236.9346.9456.9566.9666.9776.9886.

21、9997.0097707.0207.0317.0427.0537.0637.0747.0857.0967.1077.1177807.1287.1397.1507.1617.1717.1827.1937.2047.2157.2157907.2367.2477.2587.2697.2807.2917.3017.3127.3237.334温度0123456789热 电 动势mV8007.3457.3567.3677.3777.3887.3997.4107.4217.4327.4438107.4547.4657.4767.4867.4977.5087.5197.5307.5417.5528207.5637.5744.5857.5967.6077.6187.6297.6407.6517.6618307.6727.6837.6947.7057.7167.7277.7387.7497.7607.7718407.7827.7937.8047.8157.8267.8377.8487.8597.8707.8818507.8927.9047.9157.9267.9377.9487.9597.9707.9