JPS629112A - Device for preventing soot from adhering to boiler - Google Patents

Abstract

PURPOSE:To prevent a reed valve from deteriorating owing to breakage by fatigue or wear, and to make the spring constant to the reed valve changeable arbitrarily in wide range, by providing a reed valve at the blow off of an air reservoir, by connecting a wound pipe in the after-flow of the blow off, and by holding the reed valve by a variable air spring. CONSTITUTION:An air reservoir 10 constituting the housing of a sound wave generator has an air feed port 11, to which an air feed line is connected. An air blow-off 12 is provided in the inside of an air reservoir, and a reed valve 14 which opens and closes the inlet port 13 by vibration is provided at the blow off 12. In the after-flow of an blow off 12, a sound pipe 2 which communicates with the inside of a boiler furnace 1 is connected. The gap at the inlet port 13 is changed by the vibration of a reed valve 14, and the air rate blowing into the sound pipe 2 is fluctuated, then the sound pressure is produced in the sound pipe 2. The reed valve 14 is held by a variable air spring 17, as well as its another end is pivotally supported by the intermediary of a rotary joint 16. The spring constant to the reed valve 14 can arbitrarily be set by a valve 20 by controlling the applying pressure to the air spring 17.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a soot adhesion prevention device for a boiler, and more specifically, a soot adhesion prevention device for a boiler, and more specifically, a soot adhesion prevention device for a boiler, and more specifically, a combustion device for a combustion device such as a marine exhaust gas boiler, a cement waste heat boiler, a garbage incinerator, or a heating furnace. This invention relates to a technology that uses sound wave energy to prevent soot and dust generated from adhesion to heat transfer surfaces.

Conventional technology Fig. 4 shows an outline of a boiler soot adhesion prevention device using such sound wave energy, in which 1 is a boiler furnace, 2 is an acoustic tube, 3 is a sound pulse generator, and 4 is a supply air blower. -15 is a drive motor, and 6 is an air supply line.

Thus, the air supplied from the blower 4 to the sonic wave generator 3 through the supply line 6 becomes an intermittent pulse flow in this generator, is amplified in the acoustic tube 2, and becomes a sonic wave inside the boiler furnace 1. radiated. This high-energy sound wave forces soot, dust, etc. floating inside the boiler furnace 1 to move and prevents it from adhering to the heat transfer surface.

FIG. 5 shows details of a conventional example of the above-mentioned sonic wave generator 3,
30 is a sonic generator housing connected to the acoustic tube 2 communicating with the boiler furnace 1 shown in FIG. 4, and 31 is an air supply line 6 provided in this nozzle and shown in FIG. 4. is the supply air inlet to which it is connected. Further, 32 is a tube installed inside the housing 30, and this tube has an elongated opening 6 34 for introducing air 33 that has entered the inside of the housing 30 from the inlet 31 into the tube, and is formed at the tip of the tube. It has a plurality of slits 35 through which air 33 is discharged. 36 is a diaphragm attached inside the housing 30, and a porous sleeve 37 integrally attached to this diaphragm is slidably fitted into the slit 35 at the tip of the tube 32.

Therefore, the air flow discharged from the slit 35 of the tube 32 has various frequency components, and the frequency component having the resonant frequency fo of the acoustic tube 2 is amplified. Then, the sound pressure of the frequency fo acts on the diaphragm 36, causing the diaphragm to vibrate.

When the natural frequency of this diaphragm is made to match fO, the amplitude of the diaphragm 36 becomes large, and the porous sleeve 37 integrated with the diaphragm 36 is inserted into the slit 37 of the tube 32.
movement in the axial direction of the tube on the outside of the tube. Porous sleeve 3
Since the frequency of movement of 7 is fO, due to the sliding movement of this sleeve.

Hole 37a of sleeve 37 and slit 35 of tube 32
and opens and closes at frequency fo.

As a result, the air from the slit 35 is discharged in an intermittent pulse form at the resonant frequency fo of the sound tube 2, and the frequency component of the sound wave inside the sound tube is accentuated by the fo acid component. It can emit high-energy sound waves with a frequency fo acid component.

Problems to be Solved by the Invention The conventional sound wave generator as described above, however, has the following problems.

In order to generate an intermittent pulse flow of the resonance frequency fo, the hole 37a of the sleeve 37 and the slit 35 of the tube 32 need to be completely opened and closed, and for this purpose it is necessary to increase the amplitude of the diaphragm 36. .

For this purpose, it is desirable to set the natural frequency of the diaphragm 36 to fO, but in this case the diaphragm enters a resonant state, which poses a problem of fatigue damage due to vibration.

Therefore, in order to generate low frequency sound waves, the diaphragm 36
This will lower the natural frequency of
It is necessary to reduce the rigidity of the diaphragm or to increase the additional mass of the diaphragm, and whichever method is used, the strength of the diaphragm becomes a major problem.

In addition, in the conventional example, the sleeve 37 and the slit 35 portion of the tube 32 slide relative to each other, so wear occurs, making it difficult to open and close the slit 35 completely, and causing foreign matter to enter the sliding portion. occurs. Moreover, due to long-term use,
There are problems in that the natural frequency of the diaphragm 36 changes due to wear of the sleeve 37, and sliding failures are likely to occur due to deformation of the sleeve 37.

Means for Solving the Problems In order to solve the problems of the conventional art, the first invention provides a soot adhesion prevention device using sonic energy for a boiler, in which a blower port is installed in an air reservoir having an air supply port. A reed valve that vibrates to open and close the inlet is disposed at the outlet, and an acoustic tube communicating with the inside of the boiler furnace is connected downstream of the outlet.

1. In the second aspect of the present invention, such a reed valve is rotatably supported at one end thereof and supported by a variable air spring.

According to the first aspect of the present invention, the sound wave generation mechanism is a combination of a reed valve and an acoustic tube, so there is no need to match the natural frequency of the reed valve with the resonant frequency of the acoustic tube. Since it is possible to increase the rigidity of the reed valve, there is no inevitable fatigue failure of the reed valve.
Improved durability and reliability. Moreover, since the slope sound wave generating section does not have a sliding part unlike the conventional example and has a simple structure, deterioration due to wear etc. does not occur.

Furthermore, according to the second aspect of the invention, by changing the air pressure of the air spring, the spring constant of the reed valve can be changed arbitrarily and over a wide range.

Example Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a first embodiment of the present invention, in which an air reservoir 10 constituting a sonic generator housing has an air supply port 11, to which an air supply line 6 shown in FIG. 4 is connected. be done. An air outlet 12 is provided inside this air reservoir, and a reed valve 1 that vibrates to open and close the inlet 13 is provided at the air outlet.
4 is placed. Then, a fourth
An acoustic tube 2 communicating with the inside of the boiler furnace 1 shown in the figure is connected.

Thus, the supply air 15 having a constant pressure Pl inside the air reservoir 11 flows into the interior of the outlet 12 through the inlet 13, which is the gap between the outlet 12 and the reed valve 14.

The flow velocity of this incoming air is the pressure 2ri and the pressure inside the outlet P2
Determined by the difference between A fluctuating component P2' of the pressure P2 is the sound pressure inside the acoustic tube 2, which is caused by the vibration of the reed valve 14. That is, due to the vibration of the reed valve 14, the inlet 1
This is because the gap changes and the amount of air flowing into the acoustic tube 2 changes.

Since the details of the conditional expression for continuously generating the fluctuating pressure P2' in the acoustic tube are extremely complicated, a simplified approximate expression is as follows.

However, d is the gap between the inlets 130, Sr is the isolateral area of the reed valve 14, and Kr is the spring constant of the reed valve 14.

At this time, the frequency of the generated sound wave is close to the resonant frequency fO of the acoustic tube.

However, as is clear from this equation, when PH and Sr are made thicker (and d and Kr are made smaller), sound waves are more likely to be generated. Valve natural frequency fr.

is not included.

In addition, in the above equation, if the spring constant (rigidity) Kr of the reed valve is increased, the generation conditional expression will no longer be satisfied, but instead, the supply pressure Pl and isometric area Sr should be increased, or the inlet gap d should be reduced. It is possible to complement the

FIG. 2 shows a second embodiment of the present invention, in which a plurality of sound wave generators as shown in FIG. 1 are provided in the acoustic tube 2, and these sound wave generators (air reservoirs) 10a.

Air supply lines 6a and 6b are connected to the tabs, respectively. The number of sonic wave generators is determined by a reed valve 14 that produces the required sound waves being pivotally supported at one end via a rotary joint 16, and an air reservoir 10iC fixed by a variable air vent and a restraining lid 18. Further, the inside of this air spring is connected to an air supply line 19, and a regulating valve 20 is provided in the middle of this line, so that the internal pressure of the air spring 17 can be easily adjusted from the outside.

Since the reed valve 14 can freely rotate around the rotation joint 16, the spring constant (Kr in the above formula) of the reed valve 14 is determined by the spring constant of the air spring 17. That is, when there is no internal pressure in the air spring 17, the spring constant of the reed valve 14 is extremely low, and as the air spring internal pressure increases, the spring constant of the reed valve increases. Therefore,
This air spring allows the spring constant of the reed valve 14 to be set arbitrarily.

Effects of the Invention As detailed above, according to the first invention, since the sound wave generating mechanism is a combination of a reed valve and an acoustic tube, the rigidity is increased to the extent that fatigue damage due to vibration of the reed valve can be prevented. It can be made higher. Furthermore, as can be seen from the above-mentioned equation, it is no longer necessary to make the natural frequency fro of the reed valve coincide with the resonant frequency fO of the acoustic tube. Furthermore, the sound wave generating section is only a reed valve provided at the outlet, and there is no moving part such as a sliding part as in the conventional example, so damage such as wear can be prevented.

Further, according to the second invention, after determining the dimensions of the sound tube, the entrance gap of the blower port, and the air supply pressure to the air reservoir for the frequency of the sound wave to be generated, When sufficient sound wave energy is not generated due to changes in the resonant frequency of the acoustic tube due to changes in gas temperature, etc., the reed surplus σ constant can be adjusted by externally adjusting the internal pressure of the air spring that supports the reed valve. You can adjust the occurrence of a police wave by changing it. The frequency of this generated sound wave is determined by the characteristics of the acoustic tube and the spring constant of the reed valve, but since the spring constant of the reed valve can be changed by the internal pressure of the air spring, the generated frequency can also be changed within a certain range.

[Brief explanation of drawings]

Fig. 1 is a diagram showing an example of a sonic generator used in the boiler soot adhesion prevention device according to the present invention, Fig. 2 is a diagram showing an example in which a plurality of sonic generators of Fig. 1 are used, and Fig. 3 is a diagram showing an example of a sonic generator used in the boiler soot adhesion prevention device according to the present invention. FIG. 4 is a diagram showing another example of the sonic generator shown in FIG. 1, FIG. 4 is a diagram showing a conventional boiler soot adhesion prevention device, and FIG. 5 is a diagram showing the detailed structure of the sonic generator. 1. Boiler furnace, 2. Acoustic tube, 10. Air reservoir, 11
・・Air supply port, 12・・Blowout port, 13・・Inlet, 14・
・Reed valve, 15...Air, 16...Rotating joint,
17...Air spring. (1 other person) -' Figure 1 Figure 2 Figure 4 Figure 5

Claims (1)

[Scope of Claims] 1. A blower is provided in an air reservoir having an air supply port, and a reed valve that vibrates to open and close the inlet is disposed at the blower, and an acoustic valve connected to the inside of the boiler furnace is provided downstream of the blower. Made by connecting pipes,
Boiler soot adhesion prevention device. 2. A blowout is provided in an air reservoir having an air supply port, a reed valve is arranged at the blowhole to open and close the inlet by vibration, and an acoustic tube communicating with the inside of the boiler furnace is connected to the downstream side of the blowhole. A soot adhesion prevention device for a boiler comprising a reed valve rotatably supported at one end thereof and supported by a variable air spring.