JP4262877B2 - Combustion equipment with flame shield - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a combustion apparatus with a flame shield device installed in a garage, a basement, a warehouse, or the like in which a combustible material such as gasoline, thinner, or benzine that generates combustible steam is placed.
[0002]
[Prior art]
Conventionally, as shown in FIG. 7, a water heater with a flame shield device is provided with a hot water storage chamber 2 and a combustion chamber 3 above and below in a hollow cylindrical main body 1, and the combustion chamber 3 supplies air to the inside. An air supply port 4 is provided, and an exhaust passage 5 is provided which passes through the axial center of the hot water storage chamber 2 and opens to the upper part of the main body 1 to discharge the combustion gas in the combustion chamber 3 to the outside. Is provided with a flame arrester (flame shielding device) 6.
[0003]
This hot water heater with a flame shield device exchanges heat with water supplied into the hot water storage chamber 2 when the high-temperature combustion exhaust gas combusted by the main burner 3 a provided in the combustion chamber 3 passes through the exhaust passage 5. Thus, the water is heated and stored as hot water at a predetermined temperature, and the hot water is appropriately supplied to the outside.
When such a water heater is installed near a combustible material that generates combustible steam, the combustible steam may enter the air inlet 4 of the water heater and the flame in the combustion chamber 3 may propagate to ignite the combustible material. Therefore, the flame arrester 6 is provided so that the flame of the combustion chamber 3 does not leak out of the air supply port 4.
[0004]
The frame arrester 6 is a metal plate-like body provided with a large number of minute openings uniformly, such as punching metal or a lath net. Each of the combustible gases has a flame extinguishing distance in which the flame does not propagate through the passage in a gap smaller than that, and the flame arrester 6 makes the size of each opening about φ1.5 to 3 mm in order to use this. .
[0005]
[Problems to be solved by the invention]
However, since the opening of the frame arrester 6 is minute, it is easily clogged with dust such as cotton dust and sand dust. For this reason, when clogged, there was a risk of incomplete combustion due to insufficient supply of air in the combustion chamber 3 and carbon monoxide poisoning.
Then, the combustion apparatus with a flame shield apparatus of this invention aims at solving the said subject and preventing the incomplete combustion by obstruction | occlusion of an air supply path.
[0006]
[Means for Solving the Problems]
  A water heater with a flame shield device according to claim 1 of the present invention for solving the above-mentioned problems is provided.
  A main burner that mixes and burns fuel gas and combustion air, a supply passage that supplies combustion air to a combustion chamber in which the main burner is provided, and a flame that divides the supply passage into a plurality of openings In the combustion equipment with a flame shield device provided with a flame shield device for preventing the passage of
  A pilot burner that has a pilot air inlet divided into a plurality of openings separately from the flame shield device, sucks combustion air from the air inlet, mixes it with fuel gas, and burns.
  A flame detection element that outputs a detection signal corresponding to the combustion state of the pilot burner;
  An incomplete combustion prevention device for preventing incomplete combustion of the main burner from the signal of the flame detection element;
Provided,
  Inclining louvers at the pilot air inlet,The gist is that the opening of the pilot air supply port is formed in a shape that is more easily clogged than the opening of the flame shield device.
[0007]
Moreover, the water heater with a flame shield device according to claim 2 of the present invention is the water heater with a flame shield device according to claim 1,
By adjusting the total opening area of the pilot air inlet, the air suction speed of the pilot burner that sucks air in accordance with the gas supply amount can be a flow rate of 0.9 to 1 m / sec. Is the gist.
[0009]
  Further, the claims of the present invention3The hot water heater with a flame shield device according to claim 1 is the above claim 1.Or 2In the water heater with a flame shield device described in
  Direct the flame of the pilot burner approximately horizontally or diagonally downward,
  The gist of the invention is that the flame detection element is desired in the jet direction of the mixed gas of the pilot burner.
[0010]
  Further, the claims of the present invention4The hot water heater with a flame shield device according to claim3In the hot water heater with the described flame shield device,
  The flame detection element is composed of a primary thermocouple and a secondary thermocouple, the primary thermocouple is desired in the jet direction of the mixed gas of the pilot burner, and the secondary thermocouple is located above the pilot burner flame opening. Provided in
  The gist is that the secondary flame thermocouple is connected to the primary thermocouple with the polarity reversed.
[0011]
  In the combustion apparatus with a flame shield device according to claim 1 of the present invention having the above configuration, even if dust such as cotton dust or sand dust enters the air supply passage, the main burner burns incompletely due to clogging of the flame shield device Since the pilot air supply port is clogged and the pilot burner is insufficiently supplied before the combustion occurs, the flame detection element detects the deterioration of the combustion state of the pilot burner, and the incomplete combustion device operates.In addition, in the combustion apparatus with a flame shield device according to claim 1 of the present invention, since the louver is inclined and provided at the pilot air inlet, the gas passage distance is increased while keeping the thickness of the pilot air inlet thin. In addition, since dust passes while colliding with the louver surface of the pilot air inlet formed obliquely, the chance of contact increases and the pilot air inlet is likely to be clogged.
[0012]
Further, in the combustion equipment with a flame shield device according to claim 2 of the present invention, generally, dust has a flow rate that is easily collected by the filtration medium, and the flow rate of the pilot burner is adjusted to a flow rate having a high dust collection rate. By adjusting the flow rate of the main burner to the low flow rate of dust collection, the pilot air inlet can be clogged before the flame shield, and the combustion state of the pilot burner can be worsened ahead of the main burner. Incomplete combustion can be reliably prevented.
[0014]
  Further, the claims of the present invention3In the combustion equipment with a flame shield device described above, since the flame burner of the pilot burner is oriented substantially horizontally or obliquely downward, the mixture of fuel and air is ejected substantially horizontally or obliquely downward during normal combustion. A flame is formed and a flame detection element is blown. Therefore, even if the flame detection element is provided at a certain distance in the horizontal direction from the flame opening of the pilot burner, it is blown by the flame and generates a high output.
  On the other hand, if the pilot air supply port is clogged with dust and the supply air to the pilot burner is insufficient, the jet speed from the flame port will slow down and the horizontal component jet speed will also slow down, so the flame will flow vertically upward. And the flame detection element is no longer obscured. Thereby, the output of a flame detection element falls, the flame detection element can detect sharply the deterioration of the combustion state of a pilot burner, and can prevent incomplete combustion reliably.
  In addition, by providing the flame detection element at a certain distance in the horizontal direction from the flame outlet of the pilot burner, the flame formation position changes greatly between normal combustion and combustion deterioration. Become wider.
[0015]
  Further, the claims of the present invention4In the described combustion equipment with a flame shield device, the secondary thermocouple is connected to the primary thermocouple with the polarity reversed, so that the electromotive force acts as negative, and the combined electromotive force with the primary thermocouple is reduced.
  During normal combustion, the flame of the pilot burner contacts the primary thermocouple and generates a high electromotive force, but does not contact the secondary thermocouple and thus generates or does not generate a low electromotive force.
  On the other hand, when the combustion worsens, the secondary thermocouple contacts the flame of the pilot burner and generates a high electromotive force, and the flame moves away from the primary thermocouple and the electromotive force decreases, so the electromotive force of the primary thermocouple The combined electromotive force obtained by subtracting the electromotive force of the secondary thermocouple from the temperature rapidly decreases from the time of normal combustion.
  Therefore, when the secondary thermocouple is connected to the primary thermocouple with the polarity reversed, the electromotive force change at the time of deterioration of combustion becomes abrupt, and the lack of air supply can be detected sharply. Further, even if the electromotive force of each thermocouple varies, the detection timing of insufficient supply of air does not vary due to this sudden electromotive force change.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
In order to further clarify the configuration and operation of the present invention described above, a preferred embodiment of the combustion apparatus with a flame shield device of the present invention will be described below.
<< First Embodiment >>
FIG. 3 shows a schematic configuration of a water heater with a flame shield device (hereinafter simply referred to as a water heater). This water heater 10 is made of an iron case with a cylindrical upper and lower ends closed and an inner surface enameled, an outer case 30 covering the outer periphery and upper surface of the body 11, and the operation of the water heater 10. A controller 41 for control is provided.
[0017]
The main body 11 of the water heater 10 includes a cylindrical portion 12, a bottom plate portion 13 that is a flat plate that closes the lower end, and a spherical upper end plate 14 that slightly bulges upward to close the upper end. It is erected on the floor surface by leg portions 11a provided on the floor.
The main body 11 is provided with a spherical lower end plate 15 that is coaxially disposed at a predetermined position on the bottom plate 13 side and that swells slightly upward and divides the inside of the main body 11 up and down. It is divided into an upper hot water storage chamber R1 and a lower combustion chamber R2.
[0018]
The upper end plate 14 and the lower end plate 15 are provided with openings 14a and 15a at axial positions, respectively. The openings 14a and 15a extend in the axial direction at the axial positions and pass through the openings 14a and 15a. An exhaust pipe 16 that forms an exhaust passage is fixed. Further, in the exhaust pipe 16, a baffle plate 17 having a twisted plate shape is fixed between an upper position slightly separated from the lower end and an upper end position, and a spiral passage is formed along the axial direction of the main body 11. ing.
[0019]
A water supply pipe 18 and a hot water supply pipe 19 are provided from the upper end plate 14 so as to hang down into the hot water storage chamber R1. Further, the upper end plate 14 is provided with a water supply port 18a of a water supply pipe 18 for supplying water into the hot water storage chamber R1 and a hot water supply port 19a for taking out hot water in the hot water storage chamber R1. Is provided with a water drain plug 19b for discharging hot water in the hot water storage chamber R1 to the outside.
[0020]
In the combustion chamber R2, a base plate 21 is provided slightly apart from the bottom plate portion 13, and a main burner 22 is formed on the base plate 21. The main burner 22 is circular and squeezes a number of locations on the outer periphery. It is installed. A main gas supply pipe 23 penetrating the side wall of the main body 11 is connected to the main burner 22.
The side portion of the main burner 22 is provided with a normal-fire type pilot burner 25 whose tip is curved in the direction of the main burner 22, and the flame port 25c of the pilot burner 25 is oriented in a direction perpendicular to the flow of combustion air. That is, it is formed in the horizontal direction.
Further, as shown in FIG. 1, a primary thermocouple 26 (flame detection element) that detects a change state of the flame of the pilot burner 25 is spaced apart from the pilot burner 25 in a horizontal direction, along with the pilot burner 25. It is fixed to the mounting plate 24. As will be described in detail later, the primary thermocouple 26 is provided at a position where it comes into contact with the flame during normal combustion and does not come into contact with the flame when the combustion deteriorates due to insufficient supply air. That is, the heat sensitive part of the primary thermocouple 26 is on the extension of the mixed gas ejection direction of the pilot burner 25.
A sub thermocouple 28 for adjusting electromotive force, which will be described later, is provided in the vicinity of the lower portion of the flame burner of the main burner 22.
[0021]
The bottom plate 13 is formed with a large air supply port 13a for supplying all combustion air to the main burner 22 and the pilot burner 25. The large air supply port 13a has a flame arrester as a flame shield device. 27 is fixed with screws 36.
In the flame arrester 27, a pilot air supply port 27a is formed only under the pilot burner 25, and a pilot air supply plate 35 that surrounds the pilot air supply port 27a and forms an air supply chamber is fixed.
As shown in FIG. 2, the frame arrester 27 is a punched metal plate-like body having a large number of small holes 27b having a diameter of φ1.6 to 3 mm. Note that an air supply pipe may be connected to the bottom plate portion 13 and a frame arrester 27 may be interposed in the air supply pipe.
[0022]
The pilot air supply plate 35 is a metal plate-like body in which a large number of small openings 35b are formed between the louvers 35c cut and raised, and the depth of the small openings 35b is 3 to 10 mm. The shortest distance d between the slopes forming the louver 35c is 0.3 to 1.5 mm, which is smaller than the diameter of the small hole 27b of the frame arrester 27.
The pilot burner 25 communicates with the pilot air supply plate 35 through a pilot air pipe 25b connected to the pilot air supply upper plate 35a that forms a space by fitting with the pilot air supply plate 35 to form a primary air supply path. ing. In addition, a pilot gas supply pipe 25 a is connected to the pilot burner 25.
Both the main burner 22 and the pilot burner 25 suck the primary air by the gas ejected from a nozzle (not shown) connected to the gas supply pipes 23 and 25a.
[0023]
As shown in FIG. 3, the outer peripheral portion and the upper portion of the main body 11 are covered with an outer case 30 via a heat insulating material. The cylindrical portion of the outer case 30 is a heat insulating material 31 made of polyurethane resin from the upper end to the substantially upper end position of the lower end plate 15, and the lower portion is a glass fiber made of a material in which fiber glass is mixed with resin. The heat insulating material 32 is provided. On the upper surface portion of the outer case 30, an annular plate-shaped upper plate 33 is embedded in the polyurethane resin portion, and a hood 34 that covers the end of the exhaust pipe 16 protruding from the upper surface portion is attached.
[0024]
A controller 41 is provided at the outer peripheral position of the lower end of the heat insulating material 31 of the outer case 30. On the side of the controller 41, a thermostat 42 is disposed so as to protrude through the heat insulating material 31 and the cylindrical portion 12 and into the hot water storage chamber R1. In addition, an original solenoid valve for opening and closing the passages to the pilot burner 25 and the main burner 22 is built in the controller 41, and the primary thermocouple 26 and the sub thermocouple 28 are connected to the controller 41 in series with opposite polarities. ing.
Further, an alarm buzzer 44 is connected to the controller 41. The controller 41 also includes a thermostat valve that closes the main gas passage when the detected temperature of the thermostat 42 becomes equal to or higher than a predetermined value T1, stops the gas supply to the main burner 22, and the detected temperature reaches a predetermined value T2 (<T1 ) When the following occurs, the thermostat valve is opened to start the gas supply to the main burner 22, and the fire is transferred from the pilot burner 25 that also serves as the seed burner to start the combustion of the main burner 22. During combustion, air is supplied to the combustion chamber R2 by a natural draft.
[0025]
Further, the controller 41 similarly closes the gas passage to the main gas supply pipe 23 and closes the main burner 22 even when the combined electromotive force of the primary thermocouple 26 and the sub thermocouple 28 falls below a predetermined value due to insufficient supply of air. The gas supply to is stopped, incomplete combustion of the main burner 22 is prevented, and an alarm buzzer 44 is sounded.
[0026]
Next, the operation of the water heater 10 having the above-described configuration will be described.
First, the pilot burner 25 is ignited while pressing down the ignition knob 41a at the top of the controller 41. An electromotive force is generated in the primary thermocouple 26 heated by the flame formed in the horizontal direction from the flame port 25c of the pilot burner 25, and is adsorbed and held in a state where the built-in original solenoid valve is opened (at this time, once Release your hand from the ignition knob 41a). Further, when the ignition knob 41a is rotated to the left and the main gas passage is opened, the main burner 22 is ignited by transferring from the pilot burner 25. With such a start of operation of the water heater 10, the change state of the flame of the pilot burner 25 is detected by the primary thermocouple 26.
[0027]
In the state where the small opening 35b of the pilot air supply plate 35 is not clogged and the air supply to the pilot burner 25 is sufficiently performed, the flame of the pilot burner 25 becomes a solid line as shown in FIG. As shown in FIG. 4, the generated electromotive force V of the primary thermocouple 26 is stable at a high value (20 mV, solid line). On the other hand, the sub thermocouple 28 is heated by the combustion heat from the main burner 22 and generates a slight electromotive force (4 mV, broken line). Therefore, the combined electromotive force (16 mV, thick solid line) is high and exceeds the abnormal combustion determination reference value Vj (3.9 mV, one-dot chain line).
Here, since the temperature of the hot water in the hot water storage chamber R1 is still low, the thermostat valve built in the controller 41 is opened, and the combustion of gas by the main burner 22 is started.
[0028]
High-temperature combustion exhaust due to combustion moves up the exhaust pipe 16 while heating the lower end plate 15, and the combustion exhaust passes through the baffle plate 17, whereby the hot water in the hot water storage chamber R1 is heated and its temperature rises. When the hot water temperature becomes T1 or higher, the thermostat 42 detects this, closes the thermostat valve, and the main burner 22 extinguishes.
When the hot water temperature drops or hot water is discharged through the hot water supply pipe 19 and the water is replenished by the water supply from the water supply pipe 18 and the hot water temperature falls below T2, the thermostat 42 detects the temperature drop and the thermostat valve By opening, the main gas passage is opened, combustion by the main burner 22 is started again, and the hot water in the hot water storage chamber R1 is heated.
[0029]
While the hot water in the hot water storage chamber R1 is repeatedly heated by the combustion of the main burner 22 as described above, the frame arrester 27 and the pilot air supply plate 35 start to be clogged with dust. 35 is larger. The reason is described below.
1. The shortest width d of the small opening 35 b of the pilot air supply plate 35 is smaller than the small hole 27 b of the frame arrester 27.
2. Since the louver 35c is formed in the small opening 35b, the gas passage distance is longer than that of the small hole 27b penetrating vertically, so there are many opportunities for dust to contact the inner wall of the small opening 35b.
3. Since the cross section of the small opening 35b is formed obliquely, the dust passes while colliding with the slope of the louver 35c, and there are many opportunities for contact.
[0030]
For this reason, the pilot air supply plate 35 is clogged earlier than the frame arrester 27. For example, even if the pilot air supply plate 35 is completely closed due to dust clogging, the frame arrester 27 is only clogged with 20%.
When the pilot air supply plate 35 is clogged in this way, the pilot burner 25 is in a state of insufficient air supply, and the jet speed (here, horizontal jet speed) from the flame port 25c of the pilot burner 25 becomes slow. Therefore, the flame formed in the horizontal direction from the flame opening 25c flows upward as indicated by the broken line in FIG. 1 due to the draft force (buoyancy), and does not contact the primary thermocouple 26. The power V also decreases as shown by the solid line in FIG. Even if the pilot air supply plate 35 is clogged, it hardly affects the combustion of the main burner 22, so the electromotive force of the auxiliary thermocouple 28 is constant. Therefore, the detection value based on the combined electromotive force is equal to or less than the determination reference value Vj.
[0031]
Here, the reason why the auxiliary thermocouple 28 is provided will be described.
If only one primary thermocouple 26 is provided, the electromotive force generated differs depending on the type of fuel gas, and the timing of detection of insufficient supply of air may be shifted and incomplete combustion may occur.
In order to eliminate the difference in electromotive force due to the gas type, a sub thermocouple 28 connected to the primary thermocouple 26 with the polarity reversed is provided, and the sub thermocouple is shifted by the amount of deviation of the electromotive force of the primary thermocouple 26 depending on the gas type. The installation location of the sub thermocouple 28 is adjusted so as to cancel out with the electromotive force of 28. In this way, the characteristics of the combined electromotive force of the two thermocouples 26 and 28 can be made uniform regardless of the gas type.
Therefore, it is possible to eliminate the difference in detection timing due to the gas type only by adjusting the position of the auxiliary thermocouple 28 having a high degree of freedom in arrangement.
[0032]
In response to this detection result, the controller 41 turns off the built-in original solenoid valve, shuts off the supply of gas to the main burner 22, and sounds the alarm buzzer 44.
That is, before the flame arrester 27 is clogged and the main burner 22 causes incomplete combustion, the deterioration of the combustion state of the pilot burner 25 is detected and the combustion of the main burner 22 is stopped. Combustion can be prevented.
[0033]
The primary thermocouple 26 comes into contact with the flame during normal combustion, and does not come into contact with the flame when the combustion deteriorates due to insufficient supply air. Therefore, the difference in generated electromotive force becomes very large, and the controller 41 makes contact with the primary thermocouple 26 with flame. The combustion state of the pilot burner 25 can be detected sensitively depending on whether or not it is performed, and incomplete combustion of the main burner 22 can be reliably prevented.
[0034]
In response to the ringing of the alarm buzzer 44 at the time of incomplete combustion prevention operation, the user removes the clogging by removing the frame arrester 27 and the pilot air supply plate 35 from the main body 11, and is installed in the main body 11 again. The combustion operation of the main burner 22 can be returned to, and the hot water in the hot water storage chamber R1 can be heated.
[0035]
Since the flame outlet 25c of the pilot burner 25 is oriented horizontally, the primary thermocouple 26 can be provided at a certain distance in the horizontal direction from the flame opening 25c, and the flame blows the primary thermocouple 26 during normal combustion. Since it does not play when the combustion deteriorates, a large difference in electromotive force can be obtained and the combustion state of the pilot burner 25 can be detected sensitively.
[0036]
In general, since the pilot burner's flame port is provided upward, the thermocouple detects the flame based on the vertical position of the flame. In this embodiment, however, the flame port 25c of the pilot burner 25 is oriented horizontally. The formation state of the battery changes greatly from the horizontal direction to the vertical direction, and the electromotive force also changes significantly compared to the conventional pilot burner.
Therefore, in this embodiment, the place where the primary thermocouple 26 can be arranged is wide, and it is easy to lay out at the time of product design.
Further, by adjusting the installation location of the auxiliary thermocouple 28 according to the gas type, the composite electromotive force characteristics can be made equal regardless of the gas type, and therefore the timing for performing the incomplete combustion prevention process is unlikely to vary. Therefore, it is not necessary to adjust the determination reference value Vj on the controller 41 side, and the specification determination is simplified.
[0037]
Further, since the louver 35c is formed obliquely in the small opening 35b, the height (thickness) of the pilot air supply plate 35 is small and compact while keeping the gas passage distance long. In addition, by tilting the louver 35c, the shortest distance d between the slopes forming the louver 35c can be reduced, that is, the cross sectional area of each small opening 35b can be reduced, so that the louver 35c is formed vertically. It becomes easy to clog.
Further, by making the pilot burner 25 for detecting clogging also serve as an ignition burner, the number of burners is not increased, and the manufacturing cost can be reduced.
[0038]
<< Second Embodiment >>
Next, a second embodiment will be described with reference to FIGS. In addition, a different part from 1st Embodiment is demonstrated, the same code | symbol is attached | subjected about the overlapping part, and the description is abbreviate | omitted. The second embodiment is different from the first embodiment in that a secondary thermocouple 29 is provided in the vicinity of the pilot burner 25 instead of the sub thermocouple 28 provided in the vicinity of the main burner 22.
[0039]
In the second embodiment, as shown in FIG. 5, the secondary thermocouple 29 is brought into contact with the flame of the pilot burner 25 at a position spaced apart from the flame outlet 25c of the pilot burner 25 by a predetermined distance, that is, during normal combustion. First, it is provided at a position where it comes into contact with the flame when the combustion deteriorates. The primary thermocouple 26 and the secondary thermocouple 29 are connected in series with their polarities reversed. Therefore, the combined electromotive force of both is obtained by subtracting the electromotive force V (broken line) of the secondary thermocouple 29 from the electromotive force V (solid line) of the primary thermocouple 26, as shown by a thick solid line in FIG. .
[0040]
During normal combustion, the flame of the pilot burner 25 is formed in the horizontal direction from the flame opening 25c and contacts the primary thermocouple 26 to generate a large electromotive force in the primary thermocouple, while the secondary thermocouple 29 has Since there is no contact, only a small electromotive force is generated.
However, when the small opening 35b of the pilot air supply plate 35 is clogged with dust, the pilot burner 25 is short of air supply, and the flame of the pilot burner 25 that has been in contact with the primary thermocouple 26 flows upward. Thus, the secondary thermocouple 29 comes into contact, and the electromotive force generated by the primary thermocouple 26 decreases, and conversely, the generated electromotive force of the secondary thermocouple 29 increases.
[0041]
Therefore, the combined electromotive force of both the thermocouples 26 and 29 decreases rapidly and becomes equal to or less than the determination reference value Vj.
That is, by using two thermocouples to detect the flame state of the pilot burner 25, the sensitivity of the detection value is increased by the electromotive force of the secondary thermocouple 29, and the flame state can be grasped more accurately. In addition, the lack of air supply can be detected sharply.
[0042]
Furthermore, by adjusting the arrangement of the secondary thermocouple 29 according to the gas type, the characteristic of the synthetic electromotive force becomes constant without being influenced by the gas type, similarly to the sub thermocouple 28 of the first embodiment. That is, it is not necessary to provide the auxiliary thermocouple 28 of the first embodiment. Of course, the auxiliary thermocouple 28 may be provided to finely adjust the synthetic electromotive force for each gas type.
[0043]
Even if the outputs of the thermocouples 26 and 29 vary (for example, ± 10%), the composite electromotive force characteristic rapidly decreases and the inclination is large, so that the detection is based on the electromotive force of the primary thermocouple 26. The degree of air supply clogging when reaching the determination reference value Vj is unlikely to vary.
Accordingly, it is possible to stably detect an insufficient supply of air due to clogging of the pilot supply plate 35.
[0044]
As mentioned above, although embodiment of this invention was described, this invention is not limited to such embodiment at all, Of course, it can implement in a various aspect in the range which does not deviate from the meaning of this invention.
For example, in the range of the gas supply amount of the pilot burner 25, the air passage amount with respect to the total opening area of the small openings 35b of the pilot air supply plate 35 becomes a flow velocity of 0.9 to 1 m / s with a high dust collection rate. The pilot air supply plate 35 may be easily clogged by adjusting the number of small openings 35b so as to be obtained.
Generally, dust has a flow rate that is easily collected by the filtration medium. The flow rate of the pilot burner 25 is adjusted to a flow rate with a high dust collection rate, and the flow rate of the main burner 22 is adjusted to a flow rate with a low dust collection rate. Thus, the small opening 35b of the pilot air supply plate 35 is blocked before the small hole 27b of the frame arrester 27, so that the combustion state of the pilot burner 25 can be deteriorated prior to the main burner 22, and incomplete combustion is surely performed. A prevention operation can be performed.
[0045]
Further, the shape of the small opening 35b of the pilot air supply plate 35 may be circular, or a louver need not be formed.
Further, the flame outlet 25c of the pilot burner 25 may be slightly upward or may be directed obliquely downward.
A lath net may be used for the frame arrester 27, or a laminate of punching metal or a lath net may be used.
[0046]
【The invention's effect】
  As described above in detail, according to the combustion apparatus with a flame shield device according to claim 1 of the present invention, the opening of the pilot air inlet is more easily clogged than the aperture of the flame shield device. The combustion state of the pilot burner has deteriorated for the first time, and by detecting this, the incomplete combustion prevention device is operated to prevent carbon monoxide poisoning and is safe.Furthermore, because the louver is formed at the pilot air inlet, the chance of dust coming into contact with the pilot air inlet is increased, the pilot air inlet is likely to be clogged, and the combustion state of the pilot burner is deteriorated before the main burner. It is possible to reliably prevent incomplete combustion.
[0047]
Furthermore, according to the combustion apparatus with a flame shield device according to claim 2 of the present invention, the combustion state of the pilot burner is deteriorated prior to the main burner by adjusting only the pilot air inlet to a flow velocity with a high dust collection rate. Thus, it is possible to reliably prevent incomplete combustion.
[0049]
  Further claims of the present invention3According to the described combustion equipment with a flame shield device, the flame formation position at the time of normal combustion and at the time of deterioration of combustion is greatly changed with the flame burner of the pilot burner directed substantially horizontally or downward, and the supply of air is insufficient. Since the flame detection element is placed at a position where it will not be hit by the flame of the pilot burner, incomplete combustion can be reliably detected by detecting the lack of air supply sensitively depending on the presence or absence of a flame, and where the flame detection element can be placed Easy to design with increased.
[0050]
  Further claims of the present invention4According to the described combustion apparatus with a flame shield device, since the secondary thermocouple is connected to the primary thermocouple with the polarity reversed, it is possible to detect the lack of air supply with high sensitivity.
  Further, since the secondary thermocouple is provided above the flame burner of the pilot burner, it is possible to sensitively detect a change in the shape of the flame due to insufficient supply of air, and incomplete combustion can be prevented quickly.
  Moreover, even if the output of each thermocouple varies, the detection timing of insufficient supply of air does not vary due to a sudden change in output, and can be detected stably.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a burner as a first embodiment as viewed from the side.
FIG. 2 is a schematic view of a bottom plate portion as a first embodiment viewed from below.
FIG. 3 is a schematic cross-sectional view of the water heater with a flame shield device as the first embodiment as seen from the front.
FIG. 4 is a diagram showing a relationship between supply air clogging and electromotive force.
FIG. 5 is a cross-sectional view of a burner as a second embodiment as viewed from the side.
FIG. 6 is a diagram showing a relationship between supply air clogging and electromotive force.
FIG. 7 is a schematic cross-sectional view of a conventional water heater with a flame shield device as viewed from the front.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Hot water heater with a flame shield device, 11 ... Main body, 13 ... Bottom plate part, 27a ... Pilot air supply port, 35 ... Pilot air supply plate, 35b ... Small opening, 22 ... Main burner, 23 ... Main gas supply pipe, 25 ... pilot burner, 26, 28, 29 ... thermocouple, 27 ... flame arrester, 27b ... small hole, 41 ... controller, R1 ... hot water storage room, R2 ... combustion chamber.

Claims (4)

A main burner that mixes and burns fuel gas and combustion air, a supply passage that supplies combustion air to a combustion chamber in which the main burner is provided, and a flame that divides the supply passage into a plurality of openings In the combustion equipment with a flame shield device provided with a flame shield device for preventing the passage of
A pilot burner that has a pilot air inlet divided into a plurality of openings separately from the flame shield device, sucks combustion air from the air inlet, mixes it with fuel gas, and burns.
A flame detection element that outputs a detection signal corresponding to the combustion state of the pilot burner;
An incomplete combustion prevention device for preventing incomplete combustion of the main burner from the signal of the flame detection element;
A combustion apparatus with a flame shield device, characterized in that a louver is provided at an inclination in the pilot inlet port, and the opening of the pilot inlet port is formed in a shape that is more easily clogged than the opening of the flame shield device.   By adjusting the total opening area of the pilot air inlet, the air suction speed of the pilot burner that sucks air according to the gas supply amount can be a flow rate of 0.9 to 1 m / sec. The combustion apparatus with a flame shield device according to claim 1. Direct the flame of the pilot burner approximately horizontally or diagonally downward,
The combustion apparatus with a flame shield device according to claim 1 or 2, wherein the flame detecting element is desired in a jet direction of the mixed gas of the pilot burner . The flame detection element is composed of a primary thermocouple and a secondary thermocouple, the primary thermocouple is desired in the jet direction of the mixed gas of the pilot burner, and the secondary thermocouple is located above the pilot burner flame opening. Provided in
4. The combustion apparatus with a flame shield device according to claim 3, wherein the secondary flame thermocouple is connected to the primary thermocouple with the polarity reversed .

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