KR20110078637A - Apparatus for measuring gas temperature and method for measuring gas temperature using the same - Google Patents

Abstract

PURPOSE: Device and method for measuring gas temperature are provided to reduce loss of heat conduction in a process temperature measured by the temperature measuring end of thermocouple is transferred. CONSTITUTION: A device for measuring gas temperature comprises a support(22), a horizontal unit(24) and thermocouple(20). The support is installed by passing through the wall of a gas transfer pipe so that the end of the support is arranged in the gas transfer pipe. The horizontal unit is bent and extended from the end of the support and is arranged in the length direction of the gas transfer pipe. The horizontal unit comprises a temperature measuring end. The thermocouple comprises a support and a horizontal unit. Loss of heat conduction decreases as an isothermal part becomes wider by the horizontal unit of the thermocouple.

Description

Gas temperature measuring instrument and method for measuring gas temperature using same {Apparatus for measuring gas temperature and Method for measuring gas temperature using the same}

The present invention provides a gas temperature measuring device and a gas temperature measuring method using the same, which reduces heat conduction loss in the process of conducting the temperature measured by the temperature measuring stage of the thermocouple, and compensates the radiant heat loss from the thermocouple surface to the surrounding surface to compensate for the gas temperature. It relates to a gas temperature measuring instrument that can accurately calculate the gas temperature measuring method using the same.

Thermocouples are sensors made by joining two metals together to measure a wide range of temperatures using the seeback effect. They are widely used in extreme environments such as power plants and steel mills due to their high durability.

Here, the Seebeck effect is a phenomenon in which thermoelectric power is generated between two metals when two different types of metals are combined to each other, and by using the electromotive force measurement between the two metals. The temperature difference between the two contacts can be known.

1 is a cross-sectional view showing the measurement of the temperature of the gas using a thermocouple according to the prior art.

Referring to the drawings, the conventional gas temperature measuring method inserts the thermocouple 2 into the temperature measuring port 2 provided in the gas transfer pipe 1 to measure the temperature (T _g ) of the gas flowing in the tube. . At this time, the temperature measuring stage 5a of the thermocouple 2 has a temperature rise due to convection heat transfer from the gas, and the temperature of the gas from the output signal of the thermocouple 2 is proportional to the elevated temperature T _t . The temperature can be measured.

However, radiation occurs due to the temperature difference (T _t -T _s ) between the thermocouple 2 surface and the inner wall surface of the transfer pipe from the surface of the thermocouple 2 to the surrounding surface, that is, the inner wall surface of the gas transfer pipe 1. In particular, when the gas flowing in the pipe is a hot gas, the heat transfer coefficient (h) of the gas is relatively small, so that convective heat transfer from the gas to the thermocouple (2) occurs, and the difference between the gas temperature and the surrounding surface temperature is relatively large. Since the measurement error due to the radiation heat loss also increases, there is a problem that it is difficult to measure the exact gas temperature.

As such, there is a suction pyrometer as a technology to compensate for the disadvantages of the conventional thermocouple when measuring the gas temperature. Aspiration thermometer is a technique for measuring the temperature of a gas more closely by sucking the gas to be measured at a very high speed instantaneously and rapidly increasing the heat transfer coefficient of the gas.

However, suction thermometers are very useful for the purpose of measuring temperature only and do not require pressure maintenance, such as for measuring internal temperatures during fire suppression, but are difficult to apply when measuring temperature in a system that must maintain a constant pressure. There is a limit.

The present invention was devised to solve the above problems, and reduces the heat conduction loss in the process of conducting the temperature measured by the thermocouple temperature measurement stage, and compensates the radiant heat loss from the thermocouple surface to the surrounding surface to the gas temperature An object of the present invention is to provide a gas temperature measuring device capable of accurately calculating the gas temperature measuring method using the same.

In order to achieve the above object, a gas temperature measuring device according to a preferred embodiment of the present invention, the support is installed through the pipe wall of the pipe wall of the gas transfer pipe, the end is disposed in the gas transfer pipe; And a thermocouple which is bent from an end of the support portion and is arranged in the longitudinal direction of the gas transfer tube, and has a temperature measuring stage, and is widened by the horizontal portion of the thermocouple. Reduce heat conduction loss

Furthermore, the present invention provides two of the above-described thermocouples having different diameters, thereby reducing heat conduction loss as the isothermal portion is widened by the horizontal portion of the thermocouple, and radiant heat loss from each of the thermocouple surfaces to the surrounding surface. By calculating the gas temperature can be calculated.

At this time, the thermocouple may include a ceramic rod for thermocouple sensors in which two metals of different types are bonded therein; And a guide tube surrounding an outer wall of the ceramic rod for the thermocouple sensor. The ceramic rod and the guide tube for the thermocouple sensor are preferably disposed along the inside of the support portion and the horizontal portion.

In addition, the present invention, the housing is fixed while passing through the pipe wall of the gas transfer pipe, the thermocouple is fixed while passing through the hollow; is preferably further comprising a.

Here, the housing, the tube having a hollow; A cover fastened to cover one side of the tube opened by the hollow and having a through hole to communicate with the hollow of the tube; And a sealing body inserted into the hollow of the tube and having a fixing hole formed therein so as to be fixed while passing the thermocouple therein.

The housing may further include a fixing ring disposed between the tube and the sealing member to increase the fixing force of the sealing member to the tube.

In addition, the support portions of the two thermocouples may be disposed in different directions, and the housing may be configured such that each of the thermocouples is fixed while passing through the pipe wall of the gas transfer pipe.

In addition, the present invention preferably further includes a spacer having a fitting hole in which two horizontal parts of the thermocouple are fitted.

Gas temperature measuring device according to another preferred embodiment of the present invention, the gas measuring tube having a flange; And a supporting part installed through the pipe wall of the gas measuring tube so that an end thereof is disposed in the gas measuring tube, and a horizontal part bent from the end of the supporting part and arranged in the longitudinal direction of the gas measuring tube and equipped with a temperature measuring end. And two thermocouples each provided, wherein the flange of the gas measuring tube is detachable from the flange of the gas conveying tube through which the gas to be measured is transferred.

At this time, the thermocouple may include a ceramic rod for thermocouple sensors in which two metals of different types are bonded therein; And a guide tube surrounding an outer wall of the ceramic rod for the thermocouple sensor. The ceramic rod and the guide tube for the thermocouple sensor are preferably disposed along the inside of the support portion and the horizontal portion.

The present invention may further include a housing which is fixed while passing through the pipe wall of the gas measuring tube and fixed while the thermocouple passes through the hollow.

Here, the housing, the tube having a hollow; A cover fastened to cover one side of the tube opened by the hollow and having a through hole to communicate with the hollow of the tube; And a sealing body inserted into the hollow of the tube and having a fixing hole formed therein so as to be fixed while passing the thermocouple therein.

The housing may further include a fixing ring disposed between the tube and the sealing member to increase a fixing force of the sealing member to the tube.

In addition, the support portion of the two thermocouples are arranged in different directions, the housing may be configured so that each of the thermocouples are fixed while passing through the pipe wall of the gas measuring tube.

In addition, the present invention preferably further comprises a spacer formed with a fitting hole for fitting the two horizontal parts of the thermocouple spaced apart.

According to another aspect of the invention, the support; And a horizontal portion bent from an end of the support portion and having a temperature measuring end, wherein each of the support portions is disposed so that the horizontal portion is disposed in the gas transfer pipe in the longitudinal direction of the gas transfer pipe. Installing through a pipe wall of the gas transfer pipe; And calculating a gas temperature by correcting a radiant heat loss from each of the thermocouple surfaces to the surrounding surface by using the temperature detected in each of the thermocouples.

Here, the gas temperature is preferably calculated by substituting the temperature detected by each of the thermocouples into the following equation.

(T _g : gas temperature, T ₁ , T ₂ : detection temperature of each thermocouple, h ₁ , h ₂ : convective heat transfer coefficient of gas for each thermocouple, ε: emissivity, σ: Stefan Boltzmann constant)

Gas temperature measuring device according to the present invention and a gas temperature measuring method using the same, in the process of conducting the temperature measured by the temperature measuring stage of the thermocouple, due to the configuration of the horizontal portion to reduce the heat conduction loss as the isothermal portion is widened, respectively The gas temperature can be calculated by correcting radiant heat loss from the thermocouple surface to the surrounding surface.

2 is a view showing a gas temperature measuring apparatus installed in the gas transfer pipe according to a preferred embodiment of the present invention, Figures 3 and 4 are views showing the gas temperature measuring instrument of FIG.

Referring to the drawings, the present invention includes a thermocouple 20 having a support part 22 installed on the pipe wall of the gas transfer pipe 1, and a horizontal part 24 extended from the support part 22.

Here, the support 22 is installed through the pipe wall of the gas transfer pipe 1 so that the end portion is disposed in the gas transfer pipe 1. At this time, the support 22 is disposed to pass through the fastening hole (1a) of the gas transfer pipe (1).

In addition, the horizontal portion 24 is extended from the end of the support portion 22 is disposed in the longitudinal direction of the gas transfer pipe (1).

Here, the horizontal portion as a name to help explain in the drawings, refers to the longitudinal direction of the gas transfer pipe (1).

The horizontal portion 24 is provided with a temperature measuring end at the end, and measures the temperature of the gas flowing in the gas transfer pipe (1).

According to the present invention configured as described above, as the isothermal portion is widened by the horizontal portion 24 of the thermocouple 20, heat conduction loss can be reduced.

That is, the thermocouple 20 of the present invention, as the horizontal portion 24 is bent in the longitudinal direction of the gas transfer pipe (1) pipe in the support portion 22, so that the surface in contact with the isothermal gas is increased, the heat conduction It is possible to minimize the temperature distortion.

Furthermore, the present invention may include two thermocouples 20 having different diameters.

At this time, the support 22 in the two thermocouples 20, as well as can be arranged in the same direction as shown, are arranged in different directions, each of the thermocouples 20 of the gas transfer pipe (1) Two housings 40 to be described below may be configured to be fixed while passing through the pipe wall.

Here, the present invention may further include a spacer 60 having a fitting hole 60a in which two horizontal portions 24 of the thermocouple 20 are spaced apart from each other.

When the velocity of the gas flowing inside the gas delivery pipe is very fast, bending occurs at the temperature measuring end of each thermocouple 20 by a force applied from a high-speed gas, and the magnitude of the bending strain is It depends on the diameter of the thermocouple 20, thereby causing variations in the spacing or arrangement direction between each thermocouple 20.

Therefore, the spacers 60 are provided between the thermocouples 20 so that the thermocouples 20 are fixed while maintaining a constant distance, thereby changing the spacing or arrangement direction of the thermocouples 20 by bending deformation. It can prevent.

That is, the spacer 60 minimizes the gap between the two thermocouples 20 in a range that does not affect the thickness of the boundary layer of the surface of the thermocouple 20, while maintaining the spaced gap is constant and flow induced vibration, etc. For various reasons, the two thermocouples 20 are prevented from contacting each other.

In other words, each thermocouple 20 is connected to the wire 29 is drawn to the outside, the electromotive force proportional to the temperature measuring temperature of the thermocouple 20 between the wire 29 connected to each thermocouple 20 By measuring the applied electromotive force applied to the external device connected to them, the temperature of the temperature measuring stage of the thermocouple 20 can be obtained.

Here, the thermocouple 20 is provided so as to be located close to each other in order to measure the gas temperature of the same point, if the distance is too close, one thermocouple 20 is near the surface of the other thermocouple 20 This affects the velocity distribution of the flowing gas, which can cause errors in temperature measurements.

Therefore, it is desirable to minimize the gap between the thermocouples 20 within a range that does not invade the boundary layer of the surface of the other thermocouples 20.

The present invention configured as described above corrects the radiant heat loss on the surface of the thermocouple 20 due to the difference in measurement temperature caused by the different convection heat transfer coefficients of the two thermocouples 20 having different diameters.

The gas temperature can be calculated by correcting the radiant heat loss from the surface of each thermocouple 20 to the surrounding surface.

As described above, by using the temperature detected from the two thermocouples 20, the radiant heat loss from the surface of the thermocouple 20 to the surrounding surface such as the inner wall surface of the gas transfer pipe 1 is corrected, where the thermocouple 20 is installed. The gas temperature at can be easily calculated.

Then, the details of the gas temperature calculation method will be described.

First, considering the energy balance in the state in which the thermocouple 20 is inserted into the tube through which the gas flows as follows.

Convective heat transfer from the gas and radiant heat transfer from the surface of the thermocouple 20 to the surrounding surface, that is, the inner wall of the tube, make energy balance with each other as shown in Equation 1 below.

(Where h: convective heat transfer coefficient, A: heat transfer area, ε: emissivity, σ: Stefan Boltzmann constant, T _g : gas temperature, T _t : thermocouple temperature, T _s : ambient surface temperature)

Here, since two thermocouples 20 having different diameters are arranged perpendicular to the flow direction of the gas, the following equations 2 and 3 are obtained by applying the above equations to the present invention for each thermocouple 20. Each thermocouple can be subdivided into subscripts 1 and 2.

When equations 2 and 3 are solved together, equation 4 below can be obtained.

Here, the convective heat transfer coefficients h ₁ and h ₂ for each thermocouple 20 are determined by the flow rate of the gas and the diameter of the thermocouple 20, and the emissivity ε is determined according to the material of the thermocouple 20. Since the temperature of the thermocouple 20 is detected, T ₁ and T ₂ , the convective heat transfer coefficients h ₁ and h ₂ of the gas for each thermocouple 20, and the radiation rate of the thermocouple 20 are represented by Equation 4 above. Substituting (ε), the gas temperature at the position where the gas temperature measuring instrument is inserted can be finally calculated.

On the other hand, when looking at the specific components of the thermocouple 20 divided into a support and a horizontal portion, it includes a ceramic rod 26 for the thermocouple sensor bonded to the two metals, and a guide tube 28 surrounding the ceramic rod 26. .

Here, the thermocouple 20 is a voltmeter used by reading the temperature value voltage ratio over a period of time to change the voltage scale of the voltmeter to a temperature scale to read directly to the temperature.

The ceramic rod 26 for the thermocouple sensor is configured by joining two different types of metals therein to generate thermoelectric power according to the Seebeck effect.

In addition, the guide tube 28 surrounds the outer wall of the ceramic rod 26 for thermocouple sensors.

The ceramic rod 26 and the guide tube 28 for the thermocouple sensor is disposed along the interior of the support 22 and the horizontal portion 24.

In addition, the present invention further includes a housing 40 fixed while passing through the pipe wall of the gas transfer pipe 1 and fixed while the thermocouple 20 passes through the hollow 42a.

The housing 40 includes a tube 42 having a hollow 42a, a lid 44 covering the tube 42, and a sealing body 46 inserted into the hollow 42a of the tube 42. Equipped.

At this time, the tube 42 is preferably a screw portion 49 is formed on the fastening portion to be easily removable to the gas transfer pipe (1).

The cover 44 is fastened to cover one side of the tube 42 opened by the hollow 42a, and a through hole 44a is formed to communicate with the hollow 42a of the tube 42.

In addition, the sealing member 46 is inserted into the hollow 42a of the tube 42, and a fixing hole 46a is formed to be fixed while the thermocouple 20 passes therein.

The seal 46 serves to seal the gas inside the gas transfer pipe 1 so that it does not flow out.

In addition, the housing 40 further includes a fixing ring 48 disposed between the tube 42 and the sealing body 46 to increase the fixing force of the sealing body 46 with respect to the tube 42.

5 is a view showing a gas temperature measuring device according to another preferred embodiment of the present invention.

Referring to the drawings, it includes a gas measuring tube 80 having a flange 82, and the two thermocouples 20 installed in the gas measuring tube (80).

At this time, the thermocouple 20 is bent from the end of the support 22 and the support 22 is installed through the pipe wall of the gas measuring tube 80 so that the end is disposed in the gas measuring tube 80 It is provided with a horizontal portion 24 is disposed in the longitudinal direction of the gas measuring tube 80, the temperature measuring stage is mounted.

The gas temperature measuring device configured as described above is detachable from the flange 2 of the gas transfer pipe 1 through which the gas to be measured is transferred by the flange 82 of the gas measurement tube 80. The assembly mounted on the gas measuring tube 80, that is, can be easily utilized as a unit.

Here, the specific configuration of the thermocouple 20 and the configuration of the housing 40 installed through the fastening hole 80a of the gas measuring tube 80 are the same as in the above-described embodiment, and thus the description thereof will be omitted. .

On the other hand, the gas temperature measuring method according to another aspect of the present invention, the step of installing two thermocouples 20 configured as described above in the gas transfer pipe (1) through the housing 40 to the gas transfer pipe (1), and Calculating the gas temperature by correcting the radiant heat loss from the surface of each of the thermocouples 20 to the surrounding surface by using the temperature detected in each of the thermocouples 20.

As a result, the present invention, in the process of conducting the temperature measured by the temperature measuring stage of the thermocouple 20, due to the configuration of the horizontal portion 24, the heat conduction loss is reduced as the isothermal portion is widened, respectively, The gas temperature can be calculated by correcting the radiant heat loss from the surface of the thermocouple 20 to the surrounding surface.

As described above, although the present invention has been described by way of limited embodiments and drawings, the present invention is not limited thereto and is intended by those skilled in the art to which the present invention pertains. Of course, various modifications and variations are possible within the scope of the claims to be described.

1 is a cross-sectional view showing the measurement of the temperature of the gas using a thermocouple according to the prior art.

2 is a view showing that the gas temperature measuring device according to a preferred embodiment of the present invention is installed in the gas transfer pipe.

3 is a view showing a gas temperature measuring instrument of FIG.

4 is a cross-sectional view of the gas temperature meter of FIG.

5 is a view showing a gas temperature measuring device according to another preferred embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

1: gas transfer pipe 20: thermocouple

22: support portion 24: horizontal portion

26: ceramic rod for thermocouple sensor 28: guide tube

40 housing 42 tube

44 cover 46 sealed body

48: retaining ring 60: spacer

80: gas measuring tube 82: flange

Claims (17)

A support part installed through a pipe wall of the pipe wall of the gas transport pipe so that an end portion is disposed in the gas transport pipe; And a thermocouple having a horizontal portion bent from an end of the support portion and disposed in the longitudinal direction of the gas transfer pipe, the horizontal portion having a temperature measuring stage. Gas temperature measuring unit, characterized in that to reduce the heat conduction loss as the isothermal portion is widened by the horizontal portion of the thermocouple. A support part installed through the pipe wall of the gas transfer pipe so that an end portion is disposed in the gas transfer pipe; And two thermocouples each including a horizontal portion bent from an end of the support portion and disposed in the longitudinal direction of the gas transfer tube, the horizontal portion having a temperature measuring stage. The gas temperature measuring device, characterized in that to reduce the heat conduction loss as the isothermal portion is widened by the horizontal portion of the thermocouple, and to calculate the gas temperature by correcting the radiant heat loss from each of the thermocouple surface to the surrounding surface. The method according to claim 1 or 2, The thermocouple is, Ceramic rods for thermocouple sensors in which two metals of different types are bonded inside; And And a guide tube surrounding an outer wall of the ceramic rod for the thermocouple sensor. The thermocouple sensor for the ceramic rod and the guide tube is characterized in that the gas temperature measuring unit is arranged along the inside of the horizontal portion. The method according to claim 1 or 2, A housing fixed while passing through the pipe wall of the gas transfer pipe, and fixed while the thermocouple passes through the hollow; Gas temperature measuring instrument further comprises. 5. The method of claim 4, The housing, A tube with a hollow; A cover fastened to cover one side of the tube opened by the hollow and having a through hole to communicate with the hollow of the tube; And An airtight body inserted into the hollow of the tube and having a fixing hole formed therein to fix the thermocouple while passing therein; Gas temperature measuring instrument comprising a. The method of claim 5, The housing, A fixing ring disposed between the tube and the sealing body to increase a fixing force of the sealing body to the tube; Gas temperature measuring instrument further comprises. 5. The method of claim 4, Supports of the two thermocouples are arranged in different directions, Gas housing is characterized in that the two housings are configured such that each of the thermocouple is fixed while passing through the pipe wall of the gas transfer pipe. The method according to claim 1 or 2, Spacers having fitting holes formed by spaced apart from two horizontal parts of the thermocouple; Gas temperature measuring instrument further comprises. A gas measuring tube having a flange; And A support portion installed through the gas wall of the gas measurement tube so that an end portion is disposed in the gas measurement tube, and a horizontal portion bent from the end of the support portion and arranged in the longitudinal direction of the gas measurement tube and equipped with a temperature measuring end It includes two thermocouples having; The flange of the gas measuring tube, the gas temperature measuring unit, characterized in that the removable gas and the flange of the gas conveying pipe conveyed. 10. The method of claim 9, The thermocouple is, Ceramic rods for thermocouple sensors in which two metals of different types are bonded inside; And And a guide tube surrounding an outer wall of the ceramic rod for the thermocouple sensor. The thermocouple sensor for the ceramic rod and the guide tube is characterized in that the gas temperature measuring unit is arranged along the inside of the horizontal portion. 10. The method of claim 9, A housing fixed while passing through the pipe wall of the gas measuring tube, and fixed while the thermocouple passes through the hollow; Gas temperature measuring instrument further comprises. The method of claim 11, The housing, A tube with a hollow; A cover fastened to cover one side of the tube opened by the hollow and having a through hole to communicate with the hollow of the tube; And An airtight body inserted into the hollow of the tube and having a fixing hole formed therein to fix the thermocouple while passing therein; Gas temperature measuring instrument comprising a. The method of claim 12, The housing, A fixing ring disposed between the tube and the sealing body to increase a fixing force of the sealing body to the tube; Gas temperature measuring instrument further comprises. The method of claim 11, Supports of the two thermocouples are arranged in different directions, And two housings configured to fix each of the thermocouples while passing through the pipe wall of the gas measuring tube. 10. The method of claim 9, Spacers having fitting holes formed by spaced apart from two horizontal parts of the thermocouple; Gas temperature measuring instrument further comprises. Support; And a horizontal portion bent from an end of the support portion and having a temperature measuring end, wherein each of the support portions is disposed so that the horizontal portion is disposed in the gas transfer pipe in the longitudinal direction of the gas transfer pipe. Installing through a pipe wall of the gas transfer pipe; And Calculating a gas temperature by using a temperature detected at each said thermocouple, correcting radiant heat loss from each said thermocouple surface to a surrounding surface; Gas temperature measurement method comprising a. The method of claim 16, The gas temperature is, Gas temperature measurement method, characterized in that the temperature detected by each thermocouple is calculated by substituting the following equation.

(T _g : gas temperature, T ₁ , T ₂ : detection temperature of each thermocouple, h ₁ , h ₂ : convective heat transfer coefficient of gas for each thermocouple, ε: emissivity, σ: Stefan Boltzmann constant)

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