JPH11281494A - Temperature measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure the temperature of a measurement object without affected by radiation. SOLUTION: In a temperature measuring device 13 provided with a protection tube 11 which is attached to a furnace heat treating by the combustion inside the furnace and projected to inside the furnace, and a thermocouple thermometer which is stored inside the protection tube 11 and measures the furnace inside temperature via the protection tube 11, shielding members 17, 18 which cover the circumference of the protection tube 11 and shield them from the radiation by the combustion are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature measuring device for measuring the temperature in a furnace, and more particularly to a temperature measuring device suitable for measuring the temperature in a heating furnace used in an oil plant or the like. It is.

[0002]

2. Description of the Related Art Generally, in a petroleum plant or the like, heat generated when fuel is burned in a heating furnace is used to heat heavy oil or heat medium such as water and air. Usually, this type of heating furnace is provided with a temperature measuring device for detecting and monitoring the temperature of exhaust gas after fuel combustion.

FIG. 7 shows an example of a heating furnace according to the prior art. In this figure, reference numeral 1 denotes a heating furnace. Heating furnace 1
Heat generated during combustion of fuel is heated (not shown)
The heating furnace main body 2 having a combustion space 6 formed therein and an exhaust duct 3 for discharging exhaust gas generated in the heating furnace main body 2 are provided.

A burner 7 as a combustor is attached near the center of the bottom of the heating furnace body 2. The fuel supply pipe 4 to which the fuel gas is supplied and the pilot gas supply pipe 5 to which the pilot gas is supplied are connected to the burner 7. Further, a cylindrical radiation tube 8 is provided in the combustion space 6 of the heating furnace main body 2. The radiant tubes 8 radiate and transmit heat generated by combustion, and are arranged in a plurality of rings around an axis having a vertical direction as an axis.

On the other hand, the exhaust duct 3
A temperature measuring device 10 protruding into the exhaust passage 9 in the inside is provided. The temperature measuring device 10 measures the temperature of the exhaust gas discharged through the exhaust path 9. As the temperature measuring device 10, a device in which a thermocouple thermometer (not shown) is housed and protected inside a protective tube 11 made of a heat-resistant metal called a well is used.

In the heating path 1 having the above configuration, the heating furnace main body 2
In the combustion space 6, the burner 7 burns the fuel gas by the ignited pilot gas. The heated portion is heated by supplying the heat generated during the combustion. At this time, most of the generated heat is generated by the radiation tube 8.
Is efficiently transmitted by being radiated.

Here, when the gas generated during the combustion is discharged as exhaust gas from the combustion space 6 through the exhaust passage 9,
The temperature is measured by the temperature measuring device 10. At this time, the temperature of the exhaust gas passing through the exhaust path 9 is transmitted to the thermocouple thermometer via the protective tube 11 and measured.

[0008]

However, the conventional temperature measuring device as described above has the following problems. The protection tube 11 of the temperature measurement device 10 projects into the exhaust path 9 in an exposed state. Therefore, the temperature measurement device 10 is affected by radiant energy released during combustion of the fuel gas, so-called radiation, and tends to measure a numerical value higher than the actual exhaust gas temperature.
That is, the measurement value includes an error due to the influence of radiation, and there has been a problem that the temperature of the exhaust gas discharged from the exhaust duct 3 cannot be accurately measured.

The present invention has been made in view of the above points, and provides a temperature measuring device capable of accurately measuring the temperature of exhaust gas to be measured without being affected by radiation. The purpose is to:

[0010]

In order to achieve the above object, the present invention employs the following constitution. The temperature measuring device according to claim 1 is attached to a heating furnace that performs a heating process by burning the inside of the furnace, and includes a protection tube protruding into the furnace and a protection tube housed inside the protection tube. A thermocouple thermometer for measuring the temperature in the furnace, comprising a shielding member that covers the periphery of the protective tube and shields radiation due to the combustion. It is.

Therefore, in the temperature measuring device of the present invention, the thermocouple thermometer can measure the temperature inside the furnace through the protective tube. At this time, since the shielding member shields radiation due to combustion, it is possible to suppress the radiation from reaching the protection tube.

According to a second aspect of the present invention, there is provided a temperature measuring apparatus.
In the temperature measuring device described above, a plurality of the shielding members are provided so as to cover the protective tube in an overlapping manner.

Therefore, in the temperature measuring device of the present invention, since the plurality of shielding members cover the protection tube in a superposed manner, it is possible to shield radiation due to combustion for each shielding member.

According to a third aspect of the present invention, there is provided a temperature measuring apparatus.
Alternatively, in the temperature measurement device according to Item 2, the shielding member is formed with a through hole that penetrates the outside and the inside of the shielding member.

Therefore, in the temperature measuring device of the present invention, the thermocouple thermometer can measure the temperature inside the furnace through the protective tube in a state where the shielding member shields the radiation due to combustion. At this time, the exhaust gas generated at the time of combustion can flow from the outside of the shielding member through the through hole to the inside, that is, the place facing the protective tube, and can flow out of the shielding member through the through hole. .

According to a fourth aspect of the present invention, there is provided a temperature measuring apparatus.
In the temperature measurement device according to the aspect, the through-hole is provided in each of a plurality of shielding members provided so as to cover the protection tube in an overlapping manner, and the through-hole of the shielding member provided adjacent to the protection tube,
It is characterized by being formed so as to be shifted from each other.

Therefore, in the temperature measuring device of the present invention, the thermocouple thermometer can measure the temperature inside the furnace via the protective tube in a state where the shielding member shields the radiation due to combustion. At this time, the exhaust gas generated during the combustion can sequentially flow from the outside of the plurality of shielding members to the inside through the through holes, and can flow into a place facing the protection tube, and can also flow to the outside of the shielding members through the through holes. Can spill. Here, since the through holes of the adjacent shielding members are formed so as to be shifted from each other, it is possible to suppress the radiation from reaching the protective tube via these through holes.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a temperature measuring device according to the present invention will be described below with reference to FIGS. In these figures, the same components as those of FIG. 7 shown as a conventional example are denoted by the same reference numerals, and description thereof will be simplified. FIG.
In the figure, reference numeral 12 denotes a heating furnace. The heating furnace 12 includes a heating furnace main body 2 in which a combustion space 6 is formed, and an exhaust duct 3 connected to an upper portion of the heating furnace main body 2 to discharge exhaust gas generated in the combustion space 6.

A burner 7 as a combustor is provided near the center of the bottom of the heating furnace body 2.
A fuel supply pipe 4 to which fuel gas is supplied and a pilot gas supply pipe 5 to which pilot gas is supplied are connected. Further, in the combustion space 6 of the heating furnace main body 2, a plurality of cylindrical radiation tubes 8 are annularly arranged around an axis whose vertical axis is the axis.

The exhaust duct 3 is provided with a temperature measuring device 13 projecting into the exhaust passage 9 in the exhaust duct 3.
The temperature measuring device 13 measures the temperature of the exhaust gas discharged through the exhaust passage 9, and as shown in FIG.
A bushing 15 penetrating through a furnace wall 14 of the heating furnace 12 and fixed to the furnace wall 14 by welding or the like;
And a measuring device main body 16 inserted into the measuring device 5.

The measuring device body 16 includes a protective tube 11 and a thermocouple thermometer (not shown) housed inside the protective tube 11.
And shield tubes (shielding members) 17 and 18 that cover the protection tube 11 so as to overlap and cover radiation to the protection tube 11. The shield tube 17 has a cylindrical shape that is closed at one end by an end wall 19 and protrudes with the other end exposed to the exhaust passage 9.
Has a flange 21 fixedly protruding from the peripheral wall 20 and a plurality of through holes 22 formed therein. The flange 21 is fixed to the bushing 15 by a fastening member (not shown) such as a mounting screw. In addition, the end wall 19
, A protection tube 11 is detachably attached thereto and is detachably attached by screwing and unscrewing of the screw member 23.

The through hole 22 has a circular shape in a plan view, and as shown in FIG. 3A, extends through the shield tube 17 around the axis thereof so as to penetrate through the outside and inside of the shield tube 17. ° formed at intervals. In addition, these through holes 22
Are formed at regular intervals so that the positions in the axial direction are the same as shown in FIG.

The shield tube 18 has a cylindrical shape whose axis coincides with the axis of the shield tube 17. Both ends are fixed to the inside of the shield tube 17 by welding or the like via spacers 24, 24. I have. Peripheral wall 2 of shield tube 18
5, a plurality of through holes 26 are formed. Through hole 26
Has a circular shape in plan view, and penetrates through the outside and inside of the shield tube 18 as shown in FIG.
At 90 ° intervals around the axis of the shield tube 18 and FIG.
As shown in FIG. 2B, the adjacent through holes 26 are formed so as to be shifted from each other by a half pitch. The through holes 26 are formed at regular intervals in the axial direction.

Then, as shown in FIG.
The through holes 7, 26 are arranged such that the positions of the through holes 22, 26 are respectively shifted by 45 ° around the axis, and in any cross section orthogonal to the axis, the through holes 22, 26 are provided.
Are formed so as to be shifted without communicating with each other. In addition, inside the one end side of the shield tube 18, the protective tube 11 is arranged via a spacer 27 so as to have the same axis as the shield tube 18.

The protection tube 11 is called a well and is for preventing the adhesion of impurities to the thermocouple thermometer and the damage due to high temperature, and has a heat resistance such as a heat-resistant metal such as stainless steel or Inconel, or a ceramic. It is made of a material, and its tip is closed. In addition, this protection tube 1
Numeral 1 is held movably in the axial direction between the spacers 27,27.

On the other hand, as shown in FIG.
Are arranged at intervals of 120 ° around the axis between the shield tubes 17 and 18. Spacer 27
Are arranged at intervals of 120 ° around the axis between the shield tube 18 and the protection tube 11, and are fixed to the gap 8 between the shields by welding or the like.

The operation of the temperature measuring device having the above configuration will be described below. First, in the heating furnace 12 shown in FIG. 2, in the combustion space 6 of the heating furnace main body 2, the burner 7 burns the fuel gas by the ignited pilot gas, and the portion to be heated is heated by the heat generated during the combustion. Is done.

Here, the exhaust gas generated at the time of combustion reaches the temperature measuring device 13 projecting from the combustion space 6 to the exhaust passage 9. The exhaust gas first flows from the outside of the shield tube 17 to the inside of the shield tube 17 via the through hole 22. Next, the exhaust gas flows from the outside to the inside of the shield tube 18 through the through hole 26, and
The temperature of the exhaust gas flowing into the thermocouple thermometer is measured via the protection tube 11. The exhaust gas whose temperature has been measured flows out of the shield tube 18 and the inside of the shield tube 17 through the through hole 26 and the through hole 22 by the pressure of the exhaust gas that continuously flows into the inside of the shield tubes 17 and 18, It is discharged from the exhaust path 9.

Here, the protection tube 11 is a shield tube 17,
The radiation caused by the combustion is shielded by these shield tubes 17 and 18 because they are covered with each other. That is,
Gas radiation generated by the combustion is shielded by the shield tube 17 and is prevented from reaching the protection tube 11. Also,
The solid radiation generated by the shield tube 17 is shielded by the shield tube 18 and is prevented from reaching the protection tube 11. Further, through holes 22, 26 through which exhaust gas flows in and out.
Are formed so as to be shifted without communicating with each other, so that the gas radiation is also prevented from reaching the protective tube 11 through these through holes 22 and 26.

In the temperature measuring device of the present embodiment, the shield tubes 17 and 18
Since the gas radiation and solid radiation reaching 1 are shielded, the temperature measurement error due to the influence of these radiations can be reduced when measuring the exhaust gas temperature. Also, since the through holes 22 and 26 are formed in the shield tubes 17 and 18,
The exhaust gas can reach the protection tube 11 without any trouble, and the temperature of the exhaust gas can be accurately measured.

At this time, since the through holes 22 and 26 are arranged so as not to communicate with each other and to be shifted, it is possible to suppress the radiation from reaching the protection portion 11 through the through holes 22 and 26. Therefore, the temperature of the exhaust gas can be measured more accurately.

In the above-described embodiment, two shield tubes are provided. However, the present invention is not limited to this, and the effect of reducing the influence of radiation can be obtained with only one shield tube. Similarly, a configuration in which three or more shield tubes are provided may be employed. In this case, the through holes formed in each case may be arranged so as to be shifted from the through holes in the adjacent shield tube. Good.

Although the through-holes 22 and 26 have a circular shape in a plan view and the shield tubes 17 and 18 have a circular shape in a cross-section, there is no problem if they are rectangular or other shapes. Further, the protective tube 11 is configured to be covered with the shield tubes 17 and 18. However, the present invention is not limited to this. For example, a through hole is formed in the exhaust path 9 so as to block radiation and through which exhaust gas can flow. A configuration may be adopted in which a measurement chamber is provided and a protective tube 11 and a thermocouple thermometer are arranged in the measurement chamber. On the other hand, the thermocouple thermometer may be the same as that conventionally used in various fields, and the protective tube may be applied to either a grounded type or a non-grounded type.

[0034]

As described above, the temperature measuring device according to the first aspect has the thermocouple thermometer for measuring the temperature in the furnace through the protection tube, and covers the periphery of the protection tube. It is configured to include a shielding member that shields radiation due to combustion. As a result, the temperature measuring device has an effect of reducing the influence of radiation at the time of measuring the exhaust gas temperature and performing accurate temperature measurement with a small temperature measurement error.

The temperature measuring device according to claim 2 has a configuration in which a plurality of shielding members are provided so as to cover the protective tube in an overlapping manner. As a result, the temperature measurement device has the effect of reducing the influence of not only gas radiation but also solid radiation at the time of exhaust gas temperature measurement, and can perform accurate temperature measurement with a small temperature measurement error.

According to a third aspect of the present invention, there is provided a temperature measuring device, wherein a through hole is formed in the shielding member so as to penetrate the outside and the inside of the shielding member. This allows the temperature measurement device to allow the exhaust gas to reach the protective tube without hindrance, and has the effect of accurately measuring the temperature of the exhaust gas.

The temperature measuring device according to claim 4 is configured such that the through holes of the adjacent shielding members are formed so as to be shifted from each other. Thus, in this temperature measuring device,
Since the radiation can be suppressed from reaching the protection tube through the through hole, an effect that the temperature of the exhaust gas can be measured more accurately can be obtained.

[Brief description of the drawings]

FIG. 1 is a view showing an embodiment of the present invention, and is a cross-sectional view of a temperature measuring device provided with a shield tube for shielding radiation.

FIG. 2 is a view showing an embodiment of the present invention, and is a schematic configuration diagram of a heating furnace provided with a temperature measuring device.

FIGS. 3A and 3B are a sectional view and a front view, respectively, of a shield tube constituting the temperature measuring device of the present invention.

FIGS. 4A and 4B are a sectional view and a front view, respectively, of a shield tube constituting the temperature measuring device of the present invention.

FIG. 5 is a sectional view taken along line AA in FIG.

FIG. 6 is a sectional view taken along line BB in FIG. 1;

FIG. 7 is a schematic configuration diagram showing an example of a heating furnace provided with a conventional temperature measuring device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Protective tube 12 Heating furnace 13 Temperature measuring device 17, 18 Shield tube (shielding member) 22, 26 Through-hole

Claims (4)

[Claims] 1. A protection tube attached to a heating furnace for performing a heat treatment by combustion in the furnace, and a protection tube protruding into the furnace; and a temperature inside the furnace via the protection tube housed in the protection tube. A temperature measuring device comprising: a thermocouple thermometer for measuring the temperature of the thermocouple; and a shielding member that covers a periphery of the protection tube and shields radiation caused by the combustion. 2. The temperature measuring device according to claim 1, wherein a plurality of the shielding members are provided so as to cover the protective tube in an overlapping manner. 3. The temperature measuring device according to claim 1, wherein the shielding member has a through-hole passing through the outside and inside of the shielding member. 4. The temperature measuring device according to claim 3, wherein the through-hole is provided on each of a plurality of shielding members provided so as to cover the protection tube in an overlapping manner, and the through-hole of the shielding member provided adjacently. A temperature measuring device, wherein the through holes are formed so as to be shifted from each other.