JP3869653B2 - Abnormality detection method and apparatus for gas switching valve of regenerative burner - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an abnormality detection method for a gas switching valve of a regenerative burner. More specifically, the present invention relates to an abnormality detection method and apparatus for a regenerative burner gas switching valve that can reliably monitor the open / closed state of the gas switching valve and can also detect damage and abnormality of the valve body.
[0002]
[Prior art]
In a relatively high-temperature heating zone such as a continuous annealing furnace or a heat treatment furnace, a radiant tube type regenerative burner (hereinafter referred to as “heat source”) with a built-in heat storage type heat exchanger is recently used from the viewpoint of energy saving as a heater for heating in the furnace. Regenerative burner) is used. This regenerative burner includes a pair of burners having a heat storage body, and by alternately burning the burners, the heat of the exhaust gas generated by the combustion of one burner is recovered by the heat storage body of the other burner.
[0003]
A general radiant tube type regenerative burner includes a radiant tube, a pair of burners having heat storage bodies provided at both ends of the radiant tube, and a gas supply to the burner connected to the pair of burners. And a pair of gas switching valves for shut-off.
[0004]
By switching the combustion ventilation switching valve that switches between intake and exhaust of a pair of burners at predetermined time intervals (about 20 to 30 seconds), the air is introduced into the burner that performs one combustion, and the other is not combusting Exhaust and heat storage can be performed through the burner.
[0005]
Conventionally, in order to monitor the open / closed state of the gas switching valve, a proximity switch such as a limit switch has been installed on the valve body of the gas switching valve.
[0006]
[Problems to be solved by the invention]
However, since the limit switch installed in the gas switching valve is placed in a high-temperature environment around the furnace, there is a problem that failure or malfunction is likely to occur due to the limitation of the heat-resistant temperature of the limit switch.
[0007]
Further, in the monitoring of the gas switching valve by the limit switch, it is possible to confirm the opening / closing of the valve, but there is a problem that it is not possible to detect a damaged state such as distortion of the valve body.
[0008]
In particular, in the case of a heat treatment furnace equipped with multiple radiant tubes, in order to individually detect the damaged state of the valve body, it is necessary to temporarily stop the combustion of all the regenerative burners and disassemble and observe the gas switching valve. Therefore, enormous effort was required.
[0009]
The present invention has been made to solve such a problem, and it is possible to reliably monitor the open / closed state of the gas switching valve, and to detect the damage and abnormality of the valve body, and to perform gas switching of the regeneration burner. An object of the present invention is to provide a valve abnormality detection method and apparatus.
[0010]
[Means for Solving the Problems]
The abnormality detection method for the gas switching valve of the regenerative burner according to the present invention includes a radiant tube, a pair of burners provided at both ends of the radiant tube, each having a heat storage body, and the pair of burners. Of a regenerative burner that recovers heat of exhaust gas generated by combustion of one burner by a regenerator of the other burner by alternately burning the burners. An abnormality detection method for a gas switching valve,
(A) measuring the exhaust temperature of each exhaust gas exhausted through the pair of burners;
(B) through said pair of burners to calculate an average value of the respective exhaust temperature of the exhaust gas exhausted to calculate the deviation of the mean value of the exhaust temperature of the pair of burners,
(C) If a deviation of the exhaust temperature of the average value exceeds a predetermined size, it is characterized by detecting the damage of the pair of gas switching valve.
[0011]
The exhaust temperature of the pair of burners is preferably measured between the burner and the combustion ventilation switching valve.
[0012]
An abnormality detection device for a gas switching valve of a regenerative burner according to the present invention includes a radiant tube, a pair of burners provided at both ends of the radiant tube, and a gas supply to the burner connected to the pair of burners, respectively. A pair of gas switching valves for shutting off, and by alternately burning the burners, the heat of the exhaust gas generated by the combustion of one burner is recovered by the regenerator of the other burner. A detection device,
(A) a pair of temperature measuring means for measuring the exhaust temperature of each exhaust gas exhausted through the pair of burners;
(B) Deviation of the average value of the exhaust temperature of the pair of burners measured by the pair of temperature measuring means by calculating the average value of the exhaust temperatures of the exhaust gases exhausted through the pair of burners Deviation calculating means for calculating
(C) comprising a judging means for judging an abnormality of the pair of gas switching valves when the deviation of the average value of the exhaust gas temperature calculated by the deviation calculating means exceeds a predetermined magnitude. Features.
[0013]
Preferably, the pair of temperature measuring means is disposed between the burner and the combustion ventilation switching valve.
[0014]
The pair of temperature measuring means is preferably composed of a thermocouple.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Next, the abnormality detection method and apparatus for the gas switching valve of the regenerative burner of the present invention will be described in more detail with reference to the drawings. FIG. 1 is a cross-sectional explanatory view of a push-pull type regenerative burner which is an embodiment of a regenerative burner equipped with an abnormality detection device for a regenerative burner gas switching valve of the present invention, and FIG. 2 is a gas of the regenerative burner of the present invention. FIG. 3 is a cross-sectional explanatory view of a pull-type regenerative burner which is another embodiment of a regenerative burner equipped with a switching valve abnormality detection device, and FIG. 3 shows the exhaust temperature of a pair of burners during normal operation of the regenerative burner of FIG. FIG. 4 is a cross-sectional explanatory view showing an abnormal operation when one gas switching valve of the regenerative burner does not fully open, and FIG. 5 shows one gas switching valve of the regenerative burner of FIG. 1 not fully closed. 6 is a cross-sectional explanatory view showing abnormal operation in the case, FIG. 6 is a graph showing the time variation of the exhaust temperature of the pair of burners during the abnormal operation of the regeneration burner of FIGS. 4 to 5, and FIGS. FIG. 9 is an explanatory sectional view showing an abnormal operation when one gas switching valve of the energy burner does not operate at all in the fully closed state, and FIG. 9 shows a time change of the exhaust temperature of the pair of burners during the abnormal operation of the regeneration burner of FIG. It is a graph to show.
[0016]
The regenerative burner gas switching valve abnormality detection method and apparatus of the present invention can be applied to both a push-pull type regenerative burner (see FIG. 1) and a pull type regenerative burner (see FIG. 2). The specific configuration of the regenerative burner is as follows.
[0017]
The push-pull type regenerative burner shown in FIG. 1 has a U-shaped radiant tube 1 provided inside a heating furnace (not shown), and a heat storage body 7 provided at both ends of the radiant tube 1. A pair of burners 2, 3, a pair of gas switching valves 4, 5 for supplying and shutting off gas from the gas pipe 6 to the burners 2, 3, and a combustion ventilation switching connected between the pair of burners 2, 3 The four-way valve 8, the supply air blower 12 provided in the supply passage 11 of the four-way valve 8, and the exhaust blower 14 provided in the exhaust passage 13 of the four-way valve 8 are configured.
[0018]
The push-pull type regenerative burner shown in FIG. 1 has one burner 2 connected to an air supply path 11 and the other burner 3 connected to an exhaust path 13 via a four-way valve 8. Combustion air is supplied from the burner 2 into the radiant tube 1, and the combustion gas in the burner 2 can be exhausted from the burner 3 by the exhaust blower 14. Further, by switching the four-way valve 8, air can be supplied from the burner 3 and exhausted from the burner 2. In such a push-pull method, the amount of combustion gas necessary for heat-treating the material inside the heat treatment furnace (not shown) is supplied to the burners 2 and 3, and the amount of combustion air is charged according to the amount of gas supplied. The air supply blower 12 and the exhaust blower 14 are adjusted so as to obtain an appropriate ratio of gas and air.
[0019]
On the other hand, the pull-type regenerative burner shown in FIG. 2 has a U-shaped radiant tube 1 provided inside the heating furnace, and a pair of burners 2 having heat storage bodies 7 provided at both ends of the radiant tube 1. 3, a pair of gas switching valves 4, 5 for supplying and shutting off gas from the gas pipe 6 to the burners 2, 3, and a three-way valve 9 for switching combustion ventilation connected to the pair of burners 2, 3, respectively 10 and an exhaust blower 14 provided in the exhaust passage 13 of the three-way valves 9 and 10.
[0020]
The pull-type regenerative burner shown in FIG. 2 uses an exhaust blower 14 to reduce the pressure inside the radiant tube 1 to a negative pressure so that the air supply passages of the individual three-way valves 9 and 10 attached to the burners 2 and 3 are provided. Combustion air can be supplied into the radiant tube 1 through 11. In such a pull system, the amount of combustion gas necessary for heat treating the material inside the heat treatment furnace is supplied to the burners 2 and 3, and the ratio of gas to air is appropriate according to the amount of gas charged with combustion air. Thus, the pressure immediately before the exhaust blower 14 is adjusted.
[0021]
As the heat storage body 7 in FIGS. 1 and 2, an alumina small-diameter ball or an air-permeable honeycomb structured ceramic is used.
[0022]
In the regeneration burner of FIGS. 1 and 2, the pair of burners 2 and 3 is configured such that in one burner 2, the gas supplied from the gas pipe 6 is supplied to the supply passage 11 of the four-way valve 8 or the supply passage of the three-way valve 9. 11 is mixed with air introduced through 11 and burned inside the radiant tube 1 to heat the tube 1. The exhaust gas generated by the combustion passes through the heat storage body 7 of the other burner 3 through the inside of the tube 1, and the heat of the exhaust gas is used to raise the temperature of the heat storage body 7 at that time. The combustion of the pair of burners 2 and 3 is alternately performed every about 20 to 30 seconds. As a result, the radiant tube 1 can be heated at a substantially uniform temperature, and the life of the radiant tube 1 is improved. be able to. Reference numeral 15 denotes a pilot burner for igniting the burners 2 and 3.
[0023]
The regenerative burner gas switching valve abnormality detection device according to the present invention shown in FIGS. 1 and 2 uses the exhaust temperature of the pair of burners 2 and 3 to detect the opening and closing of the gas switching valve and to detect the damaged state of the valve body. .
[0024]
That is, the gas switching valve abnormality detection device according to the present embodiment has a pair of thermocouples 16 and 17 for measuring the exhaust temperatures of the exhaust gases exhausted through the pair of burners 2 and 3 (FIG. 1-2), deviation calculating means (not shown) for calculating the deviation of the exhaust temperature of the pair of burners 2, 3 measured by the pair of thermocouples 16, 17, and the deviation calculated by the deviation calculating means And a determination means (not shown) for determining abnormality of the pair of gas switching valves 4 and 5.
[0025]
The thermocouples 16 and 17 can be installed at any position in the section between the burner 2 or 3 and the exhaust blower 14 as long as the exhaust temperature of the pair of burners 2 and 3 can be measured. It is preferable to provide between the burners 2 and 3 and the four-way valve 8 or the three-way valves 9 and 10 in that the temperature can be measured accurately.
[0026]
Further, in the present embodiment, the thermocouples 16 and 17 that are inexpensive and have high measurement accuracy are adopted as means for measuring the exhaust temperature, but the present invention is not limited to this, and a resistance temperature detector or the like is used. Other temperature measuring means may be employed.
[0027]
The deviation calculating means obtains the deviation of the exhaust temperature of the burners 2 and 3 measured by the thermocouples 16 and 17, and a known personal computer or the like can be adopted.
[0028]
In addition, when the exhaust gas temperature deviation obtained by the deviation calculating means reaches a predetermined magnitude (for example, about 40 to 50 ° C.), the determination means is abnormal in either of the gas switching valves 4 and 5. A known personal computer or the like is used. The deviation calculating means and determining means may be shared by a single personal computer.
[0029]
Further, it is possible to provide alarm means for notifying an operator or the like when it is determined that the determination means is abnormal. As the alarm means, a visual appeal such as a lamp or a liquid crystal display panel or a hearing appeal such as a buzzer can be used alone or in combination.
[0030]
It is also possible to adopt a mechanism that displays the calculation result of the deviation calculating means without using the determining means, and the operator can judge the value by looking at the mechanism.
[0031]
Next, an example in which the gas switching valve abnormality detection method of the present invention is applied to various abnormal states of the gas switching valve will be described with reference to FIGS. In addition, the abnormality of the gas switching valve which generate | occur | produces also in the case of any regeneration burner of FIGS. 1-2 is the same. For safety reasons, the gas switching valve is generally provided with a spring inside, and the valve is opened only when it is pushed in with pressurized air, and gas is supplied to the burner.
[0032]
First, when the gas switching valves 4 and 5 are normal, a predetermined amount of gas can be supplied to both the burners 2 and 3, and the burners 2 and 3 can be burned at intervals of 20 to 30 seconds. By performing this operation periodically, the radiant tube 1 can be heated to around 1000 ° C. During this normal operation, the exhaust temperature of the exhaust gas exhausted through the pair of burners 2 and 3 is measured by the thermocouples 16 and 17. As shown in the graph of FIG. 3, the exhaust gas temperature T _B in the vicinity of the exhaust temperature T _A and the burner 3 in the vicinity of the burner 2 is periodically varied in the range of about 200 to 300 [° C., deviation of the mean value of the exhaust temperature It is very small and becomes a narrow range of about 0 to 20 ° C.
[0033]
Next, as an example of the case where the gas switching valve is abnormal, as shown in FIGS. 4 to 6, when the valve body of the gas switching valve 4 on the burner 2 side is deformed, the gas switching valve is fully opened and fully closed. In other words, the combustion gas leaks from the gas switching valve 4 to the burner 2 even when it is not supposed to be supplied, and the supply amount of the combustion gas is less than a predetermined amount when it is supposed to be supplied. .
[0034]
For this reason, for example, as shown in FIG. 4, when one gas switching valve 4 is not fully opened, the combustion heat generated in the burner 2 on the abnormal gas switching valve 4 side is insufficient as compared with the normal time. The amount of heat stored in the heat storage body 7 on the gas switching valve 5 side is reduced. For example, when the gas supply amount is about 70 to 80% of the normal gas amount, the heat storage body 7 on the normal gas switching valve 5 side is used. exhaust gas temperature T _B which is evacuated to a low temperature of comparison with the normal (about 200 to 250 ° C.).
[0035]
On the other hand, the combustion heat generated in the burner 3 on the normal gas switching valve 5 side is almost the same as that in the normal state (more precisely, the amount of heat stored in the heat storage body 7 on the normal gas switching valve 5 side is reduced). The temperature of the combustion air preheated through the heat storage body 7 on the switching valve 5 side is reduced), but in the vicinity of the heat storage body 7 on the abnormal gas switching valve 4 side, a normal gas switching valve Since the surplus air in the combustion exhaust gas combusted by the burner 2 on the 5 side reacts with the combustion gas leaking from the abnormal gas switching valve 4 and burns, the abnormal gas switching valve 4 valve side causes the heat storage body 7 to exhaust gas temperature T _A that is discharged via, even high temperature (300 to 350 degree ° C.) to the exhaust gas temperature T _B exhausted from the normal gas switching valve 5 side.
[0036]
Therefore, the temperature deviation T _A -T _B is generated in the exhaust gas discharged through the burner 2 and 3 with a pair of regenerator 7 (see FIG. 6). Thereby, it can be detected that either one of the gas switching valves 4 and 5 is abnormal.
[0037]
Next, as another example of the case where the gas switching valve is abnormal, as shown in FIGS. 7 to 9, when the valve body of one gas switching valve 4 stops operating at all (that is, normally closed). in state), the exhaust gas temperature T _B which is exhausted through the regenerator 7 normal gas switching valve 5 side is greatly reduced than the normal (about 100 to 150 ° C.). On the other hand, the exhaust gas temperature T _A exhausted through the heat accumulator 7 on the abnormal gas switching valve 4 side is slightly lower than normal (about 200 to 250 ° C.), but on the normal gas switching valve 5 side. a higher temperature than the exhaust gas temperature T _B which is exhausted through the regenerator 7, deviation occurs in the exhaust gas temperature T _a -T _B of the pair of burners 2, 3 in this case. Thereby, it can be detected that either one of the gas switching valves 4 and 5 is abnormal.
[0038]
As described above, when an abnormality occurs in gas switching valve 4 and 5, it is possible to detect an abnormality in an early stage by observing the deviation T _A -T _B of the exhaust gas temperature of the burner 2 and 3. Moreover, by analyzing the temperature deviation T pattern _A -T _B shown in FIGS. 6 and 9, it is possible to know also the type of abnormality of the gas changeover valve 4,5.
[0039]
【The invention's effect】
According to the present invention, the open / close state of the gas switching valve can be monitored with high reliability, and further, damage and abnormality of the valve body can be detected. Therefore, it becomes possible to remotely monitor a plurality of regenerative burners with high reliability.
[Brief description of the drawings]
FIG. 1 is a cross-sectional explanatory view of a push-pull type regenerative burner which is an embodiment of a regenerative burner equipped with an abnormality detection device for a regenerative burner gas switching valve according to the present invention.
FIG. 2 is a cross-sectional explanatory view of a pull-type regenerative burner which is another embodiment of the regenerative burner provided with the abnormality detection device for the gas switching valve of the regenerative burner of the present invention.
3 is a graph showing temporal changes in exhaust temperature of a pair of burners during normal operation of the regeneration burner of FIG. 2. FIG.
FIG. 4 is a cross-sectional explanatory view showing an abnormal operation when one gas switching valve of the regenerative burner is not fully opened.
5 is an explanatory cross-sectional view showing an abnormal operation when one gas switching valve of the regeneration burner of FIG. 1 is not fully closed. FIG.
6 is a graph showing temporal changes in exhaust temperature of a pair of burners during abnormal operation of the regeneration burner of FIGS.
7 is a cross-sectional explanatory view showing an abnormal operation when one gas switching valve of the regeneration burner of FIG. 1 does not operate at all in a fully closed state.
8 is a cross-sectional explanatory view showing an abnormal operation when one gas switching valve of the regeneration burner of FIG. 1 does not operate at all in a fully closed state.
FIG. 9 is a graph showing temporal changes in exhaust temperature of a pair of burners during abnormal operation of the regeneration burner of FIGS.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Radiant tube 2, 3 Burner 4, 5 Gas switching valve 7 Heat storage body 8 Four-way valve 9, 10 Three-way valve 16, 17 Thermocouple

Claims (5)

A radiant tube, a pair of burners having heat storage bodies provided at both ends of the radiant tube, and a pair of gas switching valves connected to the pair of burners, respectively, for supplying and shutting off gas to the burner And a method of detecting an abnormality in a gas switching valve of a regenerative burner that recovers heat of exhaust gas generated by combustion of one burner by a heat storage body of the other burner by alternately burning the burner ,
(A) measuring the exhaust temperature of each exhaust gas exhausted through the pair of burners;
(B) calculating an average value of the exhaust temperatures of the exhaust gases exhausted through the pair of burners, calculating a deviation of the average value of the exhaust temperatures of the pair of burners;
(C) If a deviation of the exhaust temperature of the average value exceeds a predetermined magnitude, the abnormality detection of the gas switching valve of regenerative burners, characterized in that for detecting the damage of the pair of gas switching valve Method.   The abnormality detection method for the gas switching valve of the regenerative burner according to claim 1, wherein the exhaust gas temperature of the pair of burners is measured between the burner and the combustion ventilation switching valve. A radiant tube, a pair of burners provided at both ends of the radiant tube, and a pair of gas switching valves respectively connected to the pair of burners for supplying and shutting off gas to the burner. An abnormality detection device for a gas switching valve of a regenerative burner that recovers heat of exhaust gas generated by combustion of one burner by a heat storage body of the other burner by
(A) a pair of temperature measuring means for measuring the exhaust temperature of each exhaust gas exhausted through the pair of burners;
(B) Deviation of the average value of the exhaust temperature of the pair of burners measured by the pair of temperature measuring means by calculating the average value of the exhaust temperatures of the exhaust gases exhausted through the pair of burners Deviation calculating means for calculating
(C) A regenerator comprising a determining unit for determining an abnormality of the pair of gas switching valves when the deviation of the average value of the exhaust temperature calculated by the deviation calculating unit exceeds a predetermined magnitude. Abnormality detection device for gas switch valve of TIB burner.   The abnormality detection device for a regenerative burner gas switching valve according to claim 3, wherein the pair of temperature measuring means is disposed between the burner and the combustion ventilation switching valve.   The abnormality detection device for a gas switching valve of a regenerative burner according to claim 3 or 4, wherein the pair of temperature measuring means comprises a thermocouple.

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