The Design and Inspection of the Thermocouple in the Breakout Prediction System

Size: px

Start display at page:

Download "The Design and Inspection of the Thermocouple in the Breakout Prediction System"

Felicity Farmer
5 years ago
Views:

1 Modern Applied Siene ol. 4, No. 11; November 2010 The Design and Inspetion of the Thermoouple in the Breakout Predition Sstem Caifeng Chen College of Mehanial Engineering, Universit of Shanghai for Siene and Tehnolog 516 Jun Gong Road, Shanghai , China Tel: Xinhua Wang College of Mehanial Engineering, Universit of Shanghai for Siene and Tehnolog 516 Jun Gong Road, Shanghai , China Tel: Abstrat Using pratial solutions and euberant eperiene in installation and inspetion as the bakground and basi theories, this essa has analzed and demonstrated the optimal design and installation and inspetion tehniques of the thermoouple on the rstallizer in the breakout predition sstem. The ontent of this essa is informative and speifi, and it has a higher pratialit in related field of asting breakout predition tehniques. Kewords: Thermoouple, Continue asting, Breakout predition sstem, Crstallizer 1. Introdution In the breakout predition sstem of asting steel, the method of measuring thermoouple Temperature is appliated, nearl b promoting the aura. the major tehnolog is to install thermoouple in the wall of rstallization so as to ollet, test, displa and handle eas Temperature hanging data of the loal areas of the rstallization, and make the orresponding alarm of molten steel leakage b the seriousness (ellow or red ard) to the operating personnel, finall finish the proess of automatiall ontrol and guide worker to produt and operate, whih an derease the (number) hane of molten steel leakage and avoid an aident. 2. The optimized design of planned spaing in the rstallization K-thermoouple in the wall of Crstallization, its planned spaing, that is, the measuring spaing of thermoouple Temperature mathes the spread speed at a mouthful of billet shell in molten steel leakage or not, will impat diretl the aura and the response to speed of steel leakage foreast sstem. Therefore, first of all, the planned spaing should be alulated and optimized. The spreading speed of the breakup of Casting billet shell is related to the asting speed of ontinue aster. When the asting speed of ontinue aster is v, for the horizontal speed of the frature billet shell is v, the vertial speed is v, the rate to the asting speed (eperiene value 0.55~0.90) has: A planned horizontal spaing of the rstallization of opper is w, the vertial spae is w, is the angle to billet shell broken line with the horizontal line, as shown in figure 1. tan For the time for broken line of billet shell etending a temperature spaing in horizontal and vertial is t and t, and the horizontal vertial spread time: The ertial spread time: W W tan W t ot Published b Canadian Center of Siene and Eduation 13

2 Modern Applied Siene ol. 4, No. 11; November 2010 t W W There are two was to get value: (1) Aording to measured value remaining in billet shell line of rstallization, when the range 0.7~ 1.6 m /min, measured value is 30 0 ~45 0 ; (2) With eperimental value t and t, the v and v in the following formula: Wt artan artan Wt is about 20 o ~45 o, for eample, when the planned horizontal spaing of the rstallization opper w is 220 mm, the vertial spae w is 220 mm, the horizontal and vertial spread time differene of the molten steel leakage: Horizontal spread time for a spae: W tan 220 tan t C ertial spread time for a spae: W 220 t As 25 o 45 o, 220tan220, t t. As tan= t /t,the relationship of horizontal and vertial spreading speed: (2.14~1) Thus, the speed of deliver of horizontal temperature is more than the vertial speed, when the plan time interval is the same, as foreasting the adhesion, the temperature of the deliver speed is quiker than the vertial speed. To enhane Aura of the steel leakage foreasting sstem, The temperature should be deteted on both diretions to redue failures in reporting or missing; being optimized, the spread time in both diretions must be equal, that is, t = t, the relationship as shown in the flowing: W =W tan This is theoretial basis in alulating the planned spaing while the thermoouple is installed in rstallization. 3. The seletion of thermoouple Choosing a right thermoouple will not onl get the eat temperature value and onformit produts, but also ma redue material onsumption to save mone and to ensure the qualit of produts. in order to guarantee the thermoouple working Reliabl and safe in bad irumstanes (working environment temperature range -20 O C~200 O C, with an amount of water vapor and a small amount of oil fields, and spae limitation, together with the vibration), our sstem uses non-standard K-thermoouple. As in figure 2, it onsists of eight parts with firm struture, magnesium insulation resistane is good and has not short iruit; the stainless steel asing an isolate full harmful media, and ompensates welding onnetion between the wire and free port of the thermoouple and proesses with sweating; the front are srewed with the thread of more than two remaining teeth, and outer seal nut mathes with PTEE seal and bolts of double head to ensure gathering the temperature data of the lower in rstallizer. Tehnial parameters instane from all parts of the thermoouple is showed as table1~4. Pa attention that length of bolts hole and aperture from different rstallization ma var, or is redesigned or infleible. It should onsider installing proess of the thermoouple and alulate the length of thermoouple and spring auratel et. the length allowane of thermoouple is less than 1mm, and that of the spring is less than 3 mm. 4. Install proesses of thermoouple To ensure that the Indiators of thermoouple meet the requirement, the rstallization must be reformed to ensure the qualit of install proess. (1) Design features of rstallization the Crstallization sheet is panel veneer b roughl mahining with 1.5 mm mahining allowane, Shown in figure 3, it is a setion of opper sheet, on the entral position there is a hole with diameter 4.5 mm and depth 7 mm and it is a gathering point of thermoouple temperature. (2) Main proess points of Crstallization installation Support the opper to the board b the epansion stud with stated tighten moment, through sealing test of 14 ISSN E-ISSN

3 Modern Applied Siene ol. 4, No. 11; November Mpa water pressure and after onformit proess it to stated size; all impurities aused b proessing must be leaned up (without water and oil )to ensure thermoouple aura. In addition, a hole is proessed on the enter of bolt to ensure thermoouple goes through it, and the thread linking with thermoouple is also proessed in the bak of it, and then hardened and tempered. Install the thermoouple sensors into the bottom of 4.5 mm hole of the opper and tight it; and bolts are tighten and sealed. This seal an prevent the water steam goes into to influene measure temperatures of thermoouple. After installing thermoouple in Crstallization, all the signal ables of thermoouple are onneted with orresponding rela ases hanging up to the rstallized with ompressed air of 3kg pressure proteting; in addition, the planned time, to guarantee installing thermoouple that there is a position of thermoouple in the water tank of the rstallization so as to weld stainless steel pipe with thermoouple going through. Thermoouple ompensate wires onnet with the remote ompensate wires with swithing quikl devie in the framework of the Crstallization. Before ompensate wires onneting transfer bo, the should installed the asing against high temperature for their being eposed outside of the Crstallization to prevent steel leakage and ontating steel water. A vent should be set in the transfer bo to blow wind for proteting ases and keep dr inside it. A shield tube (diameter 40 mm) should be set in the losure of ompensate wires and then tight them with a setting or throat to avoid ompensate wires nudit outside when it slips. We must pa attention to the model and polarit using Thermoouple ompensate wires, the Temperature in the onnetion of Compensate wires and thermoouple ould not more than 100 O C. It will reate the major errors of thermoouple when thermoouple is set error, for eample, installing position and inserting depth of thermoouple ould not reflet the real temperature of opper sheet. Therefore, inserting depth of thermoouple should be at least 8 to 10 times as the diameter of the protetion ase; for there is no insulation material between protetion tube of thermoouple and wall so that heat t gas overflows and ooling water invades it should be sealed with PTEE between protetion tube of thermoouple and Crstallization hole. At the same time, we should tr to avoid strong magneti and eletri field and not to put thermoouple and power able in one onduit to avoid the error aused b the disturbane. replaing thermoouple when it is damaged, we should install it in the hole and tighten it with a wrenh bolt; we push PTEE sealing ring the gap between tapered bolt and ompensation wire and tighten sealing nut properl without tighting seriousl so as to damage PTEE sealing ring. 5. Detet wa to thermoouple In order to guarantee installing qualit and eliminate the error signal during installation proess, we must test all the thermoouple. Detetion methods off-line: mark eah position of n thermoouple of opper sheet in turn, and reord the temperature that thermoouple shows at ambient temperature, for the number of thermoouple and the temperature are reorded as T 11, T 12,, T 1n. then adjust gas welding to the neutral flame to bake eah mark point about 15 seonds; and reord the temperature that thermoouple shows when baked, for the are T 21, T 22,, T 2n. In addition, in order to redue deteting influene among eah mark point, the operation order of roasted point an test in odd or even sequene so that we an take test point with the greatest distane and not to miss deteting point with minimum errors. We an determine temperature differene whether to meet the requirements of formula.in aordane with the following three onditions to analsis data. T ma( T T T ma( T T T min( T T z 1i 2i 2i 1 j 1 j o ) 1.8 C 2 j o ) 4.5 C o ) 8.2 C ( i 1,2,,n j 1,2,,n ) Reason for temperature differene, the first is manual operation; the seond is devie differenes, and the third is sstem influene. Therefore, this is not onl indiators of qualit of design and installation, but also that of sstem. For T ij point being disontent to ondition it is not diffiult to identif auratel the orresponding thermoouple and line fault, before using the devie, we an eliminate it to seurit steel leakage foreast sstem to displa. Inspetion on-line: The testing error of temperature will be larger beause of devie and material being polluted, Published b Canadian Center of Siene and Eduation 15

4 Modern Applied Siene ol. 4, No. 11; November 2010 deformation, oidation insulation resistane beond prodution and it will be more serious in high temperature. This not onl auses wastage of hot eletri potential, but also introdues interferene; therefore, the error of resulting temperature is sometimes up to 100 degrees. If we use omputer foreast sstem of steel leakage b sstems, it an san and analsis point T ij timing, and an judge whether or not the value of point T ij hanges and range abilit is in the normal range. If there are eeptions, the operator will shield the orresponding monitoring point, or automati shield orresponding monitoring point. At the same time, the sstem prompts running maintenane personnel spot heks in time in order to ahieve inspetion apabilities on-line automati. 6. Conlusion In foreasting sstem of asting steel leakage, making design, installation and testing of thermoouple well would greatl enhane reliabilit of sstem, redue the maintenane work greatl, and make foreasting of sstem steel leakage produtive. Aknowledgment This work is Supported b Shanghai Leading Aademi Disipline Projet,Projet Number:J50503 Referenes Minghong. Lishimin. (2002). Influene for ompensation wires to thermoouple test results. journal of southwest petroleum institute ~78. Shi wenkang Yu iaofen. (2010). Detetion tehnolog. The third edition. Beijing: Mahiner industr press. (Chapter 3). Wang azhen. (2005). tehnolog and equipment for ast steel. Beijing: Metallurg industr press. (Chapter 1). Table 1. The omponents Indiators name indiators data thermoouple perating temperature 200 C thermoouple graduation Thermoouple lass enapsulate form of The omponents insulation material insulation resistane between the positive and negative harges eternal diameter of protetive tube thermal response timeτ0.5 K tpe 0.4, ±0.4% full quantum isolated and sheathed magnesium oide >100MΩ 2.0mm 0.5seond Table 2. Spring Indiators name inside diameter eternal diameter material indiators data 4.0 mm 4.0 mm rustless steel Spring Table 3. Rivets (the ase of 2.0mm thermoouple) Indiators name eternal diameter material indiators data 4.0 mm Copper 16 ISSN E-ISSN

www.senet.org/mas Modern Applied Siene ol. 4, No. 11; November 2010 Table 4.

temperature of ompensating lead 100 C Thermoouple 4.0mm the number of K tpe fastener inside Compensation wire diameter Thermoouple With M8 thread eternal diameter 4.

5 Modern Applied Siene ol. 4, No. 11; November 2010 Table 4. Tehnial speifiations of Connetion (with soket devie) and ompensate wire Indiators name indiators data Indiators name indiators data Thermoouple fastener srew thread Corresponding Rp1/4,threads the temperature of ompensating lead 100 C Thermoouple 4.0mm the number of K tpe fastener inside Compensation wire diameter Thermoouple With M8 thread eternal diameter 4.0mm onnetion form onnetion of wire tube Thermoouple onnetion material Thermoouple onnetion ores Engineering plastis +pure opper Wire form onnetion 3 ores Wire onnetion material Wire ores onnetion With M8 thread onnetion Engineering plastis +pure opper 3 ores Figure 1. Shemati diagram of frature line etension bond Figure 2. Chart of speial thermoouple Published b Canadian Center of Siene and Eduation 17

www.senet.org/mas Modern Applied Siene ol. 4, No. 11; November 2010 Figure 3.

6 Modern Applied Siene ol. 4, No. 11; November 2010 Figure 3. Proessing graph of Crstallization opper mahine 18 ISSN E-ISSN

DIGITAL DISTANCE RELAYING SCHEME FOR PARALLEL TRANSMISSION LINES DURING INTER-CIRCUIT FAULTS

CHAPTER 4 DIGITAL DISTANCE RELAYING SCHEME FOR PARALLEL TRANSMISSION LINES DURING INTER-CIRCUIT FAULTS 4.1 INTRODUCTION Around the world, environmental and ost onsiousness are foring utilities to install