JP2675334B2 - High temperature fluid temperature measuring device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a temperature measuring device for a high temperature fluid, and particularly to a temperature of a high temperature fluid surrounded by a wall, such as a high temperature gas fluid in a boiler furnace. The present invention relates to a temperature measuring device for a high temperature fluid, which measures based on a propagation time of a sound wave.

[Conventional technology]

One of the methods for measuring the temperature inside the furnace is to use a sound wave. An example is shown in FIG. In FIG. 5, the sound wave is transmitted from the transmitter 7, transmitted through the gas 10 in the furnace, and detected by the receiver 8. Then, the control device 9 calculates the propagation time from transmission to detection. The propagation time t (sec) and the in-furnace gas temperature T (k) have the following relationship.

α: constant determined by gas properties l: distance from transmitter to receiver (m) Using this relational expression (1), the average temperature T of the gas in the furnace is calculated from the propagation time.

As an application of FIG. 5, there is a method shown in FIG. Sixth
In the figure, a sound wave transmitter, a sound wave receiver, or those having both functions (hereinafter, these 3
A plurality of them will be collectively referred to as sound wave sensors) 3 are arranged around the furnace wall 5. Then, the temperature distribution of the cross section is calculated by measuring the propagation times of many paths in the furnace by these.

The temperature measuring device in the furnace using the above sound waves,
A cooling function is required to protect the acoustic wave sensor attached to the furnace wall from heat inside the furnace.

The conventional device is as shown in FIG. 7 or FIG.

In FIG. 7, a bent waveguide 6 is attached to a horn 4 attached to a furnace wall 5, and then a sound wave sensor 3 is attached. The waveguide 6 is provided with the cooling air ejection port 2 to protect the acoustic wave sensor from the heat inside the furnace by flowing air into the waveguide.

In FIG. 8, the cooling air jet port 2 is provided behind the sound wave sensor 3.
Is provided, and the acoustic wave sensor is cooled by flowing cooling air from there.

Although the above method has been conventionally used, a device having higher heat resistance and a device capable of more accurate measurement are required.

[Problems to be solved by the invention]

In FIG. 7, the sound wave transmitted from the sound wave transmitter to the sound wave receiver is not only transmitted in the gas in the furnace but also in the cooling air in the waveguide. Therefore, in order to accurately measure the sound wave propagation time only in the gas in the furnace, it is necessary to make a correction in consideration of the sound wave propagation time propagating in the cooling air in the waveguide. For this correction, it is necessary to know the temperature of the air in the waveguide, but the temperature of the air in the waveguide is high inside the furnace and low on the acoustic sensor side over the length of the waveguide. Due to the steep slope, its accurate measurement is difficult. Furthermore, by placing the acoustic wave sensor away from the furnace wall, the received sound waves are attenuated in the waveguide and then transmitted into the furnace, and the propagated sound waves are attenuated in the waveguide at the receiving side. , Detected. That is, the function of the sound wave sensor is deteriorated.

In the case of FIG. 8, the surface inside the furnace of the acoustic wave sensor becomes high in temperature due to the radiant heat from the inside of the furnace. As shown by the arrow in FIG. 8, the flow of cooling air does not reach the surface of the acoustic sensor inside the furnace sufficiently. That is, as the temperature inside the furnace becomes higher, sufficient cooling cannot be achieved.

It is an object of the present invention to adequately protect the acoustic wave sensor from heat in the furnace without compromising the function of the acoustic wave sensor.

[Means for solving the problem]

The above-mentioned problems of the conventional technology include a sound wave transmitting device and a sound wave receiving device which are provided at opposite positions of a wall surrounding a high temperature fluid, and a device which calculates a propagation time of a sound wave from the sound wave transmitting device to the sound wave receiving device. In the temperature measuring device of the high temperature fluid for obtaining the temperature of the high temperature fluid from the propagation time of the sound wave, the sound wave transmitting device and the sound wave receiving device provided on the wall are provided with a heat shield between the high temperature fluid and the space. This is solved by a high temperature fluid temperature measuring device characterized by the above.

In the present invention, the heat shield is composed of, for example, a plurality of heat-resistant porous plates, and the positions of the holes of each porous plate are arranged so that the positions of the holes of one porous plate are not the holes of the other porous plate. It is a heat shield that is installed by shifting.

〔Example〕

FIG. 1 shows an embodiment of a sound wave transmitting / receiving apparatus according to the present invention. In this embodiment, this device has an internal gas temperature of about 1300
It was installed in a 2m x 2m gas boiler at ℃. First, the heat shield 12 is placed inside the furnace of the sonic sensor. The heat shield 12 is required to have a function of blocking radiant heat from the inside of the furnace and passing a sound wave. Therefore, the heat shield 12 is composed of three ceramic perforated plates, as shown in FIG. The size of the holes 13 is 5 mm, and the distance between the holes is 8 mm. Then, as shown in FIG.
The part that is not the second or third hole at the hole position of the first plate
14 can be installed so that the spacing between the perforated plates is 5 mm. The radiant heat is an electromagnetic wave of 1 to 100 μm and has a very short wavelength with respect to the gap of the heat shield, so that it hardly passes by the diffraction phenomenon, and most of it is blocked by the heat shield 12. On the other hand, the wavelength of sound is much longer than that of radiant heat. 20kH in this embodiment
The z frequency is used, and its wavelength is 2.47 cm at 500 ° C.
It is. Therefore, the sound wave can pass through the holes of the three plates due to the diffraction phenomenon.

Next, in order to cool the heat shield 12, FIG.
An air jet 11 is provided as shown in FIG. This is to prevent the sound wave sensor from being overheated by radiant heat from the shield when the shield reaches a high temperature. In this example, the shield was cooled to 400-500 ° C.

Further, in order to directly cool the sound wave sensor 3, as shown in FIG. 3 (enlarged view of part B in FIG. 1), the sound wave sensor is wound and the air ejection port is arranged between the sound wave sensor 3 and the shield 12. . In the present embodiment, the apparatus according to the present invention is attached to the furnace wall of the boiler whose furnace gas temperature is 1300 ± 200 ° C., the temperature of the shield is kept at 400 to 500 ° C., and the sound wave sensor is 80
° C. With the above configuration, the acoustic wave sensor is protected from the heat inside the furnace.

Also in this embodiment, the sound wave is transmitted through the cooling air between the sound wave sensor and the shield, but this uses a sound wave sensor having both transmission and reception, or the apparatus has both a transmitter and a receiver. By installing, it can be easily corrected as follows. In this example, the device was equipped with both a transmitter and a receiver. When measuring the acoustic wave propagation time in the furnace from one transmitter to the other receiver, first the acoustic wave is transmitted by the transmitter on the transmitting side, and a small part of it is reflected by the shield. This reflected wave is received by a receiver mounted in the same device, and the propagation time tA from its transmission to reception is measured. Next, the same operation is performed on the receiving side, and tB
Is measured. After that, a sound wave is transmitted from the transmitting side and is received by the receiving side, so that the propagation time t during that time is measured. From the above operation, the propagation time in the furnace is As easily and accurately corrected.

Further, in this embodiment, the electromagnetic valve 15 is attached to the air pipe 1 as shown in FIG. 1 in order to prevent the jetted sound wave of the cooling air from becoming noise when receiving the sound wave. This solenoid valve 15 transmits a sound wave from one side as shown in FIG. 4, and the valve is closed only while the sound wave is received on the other side,
The control device 9 controls so as to stop the air jet noise. In this embodiment, a ceramic plate is used as the shield, but if it is heat resistant, it has the same function.

Although the heat shield 12 is installed at the tip of the horn 4 in the present embodiment, the effect is the same even if the heat shield 12 is installed in the middle of the horn 4.

〔The invention's effect〕

According to the present invention, it is possible to completely prevent the sound wave transmitting / receiving sensor from being overheated due to radiation from the high temperature fluid in the wall, and to install the sound wave sensor without separating from the wall by using a waveguide. , More accurate measurement is possible.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an embodiment of the present invention, and FIG.
FIG. 3 is a detailed view of the cooling part of the heat shield device, FIG. 3 is a detailed view of the cooling part of the sound wave transmission / reception sensor, FIG. 4 is an explanatory view of a cooling air circuit in the embodiment of the present invention, and FIGS. Explanatory diagram of sound measurement device for in-furnace gas using sound waves, which will become a technology
FIGS. 8A and 8B are explanatory diagrams of a sound wave sensor according to a conventional technique. DESCRIPTION OF SYMBOLS 1 ... Air piping, 2 ... Air ejection port, 3 ... (Transmission / reception) sound wave sensor, 5 ... Furnace wall, 9 ... Control device (transmission time calculation device), 10 ... High temperature gas in the furnace, 12 ... Heat shield.

Claims (2)

(57) [Claims] 1. A sound wave transmitting device and a sound wave receiving device which are provided at opposite positions of a wall surrounding a high temperature fluid, and a device which calculates a propagation time of a sound wave from the sound wave transmitting device to the sound wave receiving device. In a temperature measuring device for a high temperature fluid that obtains the temperature of the high temperature fluid by the propagation time of the heat wave, the sound wave transmitting device and the sound wave receiving device provided on the wall are provided with a heat shield between the high temperature fluid and a space. Measuring device for high temperature fluid. 2. The heat shield comprises a plurality of heat-resistant porous plates, and the positions of the holes of each porous plate are adjusted so that the positions of the holes of one porous plate are not the holes of the other porous plate. The temperature measuring device for a high-temperature fluid according to claim 1, wherein the heat-shielding plates are attached in a shifted manner.