JPH0875155A - Gas burner - Google Patents

Abstract

PURPOSE: To provide a gas combustion device which makes it possible to control an air/fuel ratio with high accuracy. CONSTITUTION: In a casing 10, an air is supplied to an air chamber 16 located below a gas burner 20 by a rotary motion of a fan 20. Gas is supplied to the gas burner 20 from a nozzle of a nozzle holder 40. A gas pressure on the downstream side of a valve port 68 communicating with the nozzle of the nozzle holder is controlled with a pressure proportional control valve 70. The pressure in an air chamber 15 is supplied to a back pressure chamber 73 of the pressure proportional control valve, thereby committing back pressure-compensation of the supply gas pressure. The amount of air to the air chamber is detected based on the difference between the pressure in the air chamber and the pressure in a combustion chamber. The rotary speed of the fan is controlled so that the detected amount of air may conform to the amount of supply gas. The air chamber 15 communicates with an equalizing chamber 202 by way of a communication port 200. A pressure introduction port 81a of the back pressure compensation means and a pressure introduction port 91a of the air quantity detection means are connected to the equalizing chamber 202.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a gas combustion device.

[0002]

2. Description of the Related Art Taking a general gas combustion apparatus as an example, a gas burner is housed in a housing space of a casing, and the housing space is partitioned by a lower air chamber and an upper combustion chamber by the gas burner. . A fan is attached to the bottom wall of the casing, and the air from the fan is sent to the air chamber. Further, the casing is provided with a nozzle holder below the gas burner. The gas burner has an inlet facing the air chamber, receives the gas injected from the nozzle portion of the nozzle holder at the inlet, receives air from the fan, mixes these gas and air inside, The mixed gas is injected from the flame mouth into the combustion chamber.

The gas combustion apparatus further includes an electromagnetic pressure proportional control valve (pressure control valve) for feeding the gas whose pressure is controlled to the nozzle holder. This pressure proportional control valve controls the gas pressure on the downstream side of the valve port connected to the nozzle portion of the nozzle holder by the supply current to the solenoid. The supply current to the solenoid is controlled by a control unit or the like so that a desired gas pressure can be supplied.
By the way, the air from the fan is sent into the air chamber, and an air pressure higher than the atmospheric pressure is generated. Therefore, the gas injection amount from the nozzle portion of the nozzle holder corresponds to the pressure obtained by subtracting the air pressure in the air chamber of the casing from the supply pressure from the pressure proportional control valve (pressure on the downstream side of the valve port). When the pressure in the air chamber fluctuates, the gas injection amount also fluctuates. Therefore, a back pressure chamber is formed in the pressure proportional control valve, the air pressure in the casing is received as a back pressure, and the opening degree of the valve opening is increased by an amount corresponding to this back pressure. Therefore, the means for compensating the back pressure comprises a pressure introducing port for introducing the pressure of the air chamber, and a communication passage connecting the pressure introducing port to the back pressure chamber of the pressure proportional control valve, for example, a pipe. There is.
This pressure introduction port is provided in the wall of the casing.

The gas combustion apparatus further comprises an air volume detection means and an air volume control means in order to make the air volume an optimum ratio to the gas volume supplied to the gas burner.
More specifically, the air volume detecting means includes two pressure introducing ports formed in the wall of the casing and facing the air chamber and the combustion chamber, a bypass passage connecting these pressure introducing ports, and an air volume provided in the bypass passage. The sensor has a flow velocity sensor and a differential pressure sensor. Since the flow velocity signal and the differential pressure signal from these sensors correspond to the supply air volume (the supply air volume per unit time) sent from the fan to the air chamber, the supply air volume can be detected from these signals. The air volume control means, the detected air volume,
The fan is controlled so that the target air volume matches the supply gas volume.

[0005]

In the gas combustion apparatus having the above-mentioned structure, the pressure introducing port of the back pressure compensating means for introducing the air chamber pressure and the pressure introducing port of the air volume detecting means are different from each other in the air chamber of the casing. Being located in place, it had the following inconveniences. That is, since air flows in the air chamber as the fan rotates, the pressure distribution in the air chamber is non-uniform. For this reason, the pressure information of the air chamber introduced through the pressure introduction port of the air volume detection means may differ from the pressure information of the air chamber introduced through the pressure introduction port of the back pressure compensation means. As described above, the pressure information of the air chamber used by the back pressure compensating means relates to the gas supply, and the pressure information of the air chamber detected by the air volume detecting means relates to the supply air volume. If the pressure information of the air chamber used by the means is different, the ratio of the supply gas amount to the supply air amount (so-called air-fuel ratio) cannot be optimally controlled with high accuracy.

[0006]

The present invention has been made to solve the above problems, and in a gas combustion apparatus according to the first aspect of the present invention, a pressure equalizing chamber is connected to the air chamber via a communication port. The pressure introducing port of the back pressure compensating means and the pressure introducing port of the air volume detecting means are connected to the pressure equalizing chamber. According to the invention of claim 2,
The gas combustion apparatus according to claim 1, wherein the nozzle holder includes a body formed by die casting, and the body is provided with the pressure equalizing chamber and the communication port that connects the pressure equalizing chamber and the air chamber. It is characterized by being.
According to a third aspect of the present invention, in the gas combustion device according to the first aspect, the pressure equalizing chamber is provided in a casing, and the gas combustion device according to the first aspect. Claim 4
In the invention of claim 1, the gas combustion apparatus according to any one of claims 1 to 3, further comprising a second pressure equalizing chamber separated from the casing, and the second pressure equalizing chamber is first provided via a communication pipe. The second pressure equalizing chamber is connected to the pressure equalizing chamber described above, and the pressure introducing port of the back pressure compensating means and the pressure introducing port of the air volume detecting means are connected to the second pressure equalizing chamber. According to a fifth aspect of the present invention, in the gas combustion apparatus according to the first aspect, the pressure equalizing chamber is arranged apart from the casing, and is connected to the air chamber via a communication pipe. The gas combustion apparatus according to the invention of claim 6 is characterized in that a common pressure introducing port of the back pressure compensating means and the air volume detecting means is connected to a predetermined portion of the air chamber.

[0007]

According to the invention of claim 1, the pressure of the air chamber of the casing is supplied to the pressure equalizing chamber, and the pressure is substantially equalized in the pressure equalizing chamber. Since the pressure introducing port of the back pressure compensating means and the pressure introducing port of the air volume detecting means are connected to the pressure equalizing chamber, the pressure information of the air chamber introduced through the pressure introducing port of the back pressure compensating means and the air volume detecting means. The pressure information of the air chamber introduced through the pressure introduction port is equal. As a result, the ratio (air-fuel ratio) between the supply gas amount and the supply air amount can be optimally controlled with high accuracy. Further, in the invention of claim 1, since the pulsation of the pressure of the air chamber is absorbed in the pressure equalizing chamber, the pressure of the air chamber taken out from the pressure introducing port connected to the pressure equalizing chamber is equal to that of the air in the air chamber. Stable with little influence of flow. As a result, the back pressure compensation and the supply air volume can be stabilized. According to the second aspect of the invention, since the communication port and the pressure equalizing chamber are formed in the nozzle holder made of die casting, the manufacturing cost can be reduced. According to the invention of claim 3, the pressure equalizing chamber is provided in the casing, and the installation position of the pressure equalizing chamber can be relatively freely selected. In the invention of claim 4, the pressure fluctuation of the air chamber is absorbed in the first pressure equalizing chamber. When there is a solenoid valve for capacity switching downstream of the pressure proportional control valve, the pressure wave generated by the opening / closing operation of this solenoid valve is transmitted to the back pressure chamber of the pressure proportional control valve. The pressure wave can be prevented from being absorbed in the second pressure equalizing chamber and being transmitted to the pressure introducing port of the air volume detecting means. This allows
Stable air volume detection can be secured. According to the invention of claim 5,
Since the pressure equalizing chamber is separated from the casing, the range of choices for the installation location of the pressure equalizing chamber and the structure of the back pressure compensating means and the air volume detecting means is expanded. In the invention of claim 6, since the pressure introduction port of the back pressure compensating means and the air volume detecting means are common, the pressure information of the same air chamber can be obtained. As a result, similarly to the first aspect, the air-fuel ratio can be optimally controlled with high accuracy.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS. The gas combustion device includes a casing 10. The casing 10 includes a horizontal bottom wall 11 and side walls 12,
13, a front wall (not shown) and a rear wall 14,
It has a rectangular parallelepiped shape. A fan 20 is attached to the bottom wall 11 of the casing 10. Casing 10
A gas burner 30 formed by arranging and assembling a large number of flat burner elements is housed in the housing space 15 inside. The gas burner 30 has a rectangular planar shape and occupies most of the cross-sectional area of the accommodation space 15. Therefore, the gas burner 30 divides the accommodation space 15 into a lower air chamber 16 and an upper combustion chamber 17. As shown in FIG. 2, the inlet 31 of each burner element is
6 facing the rear wall 14.

A nozzle holder 40 is attached to the rear wall 14 of the casing 10 below the gas burner 30. A heat exchanger 50 is attached to the upper end of the casing 10.

The structure of a known portion of the nozzle holder 40 will be described. As shown in FIG. 2, the nozzle holder 40 has a body 41 formed by die casting and a back plate 42 fixed to the back side of the body 41. This body 4
1 has a front wall 43 and a peripheral wall 44, and an internal space is formed by both. As shown in FIG. 1, a gas inlet 44a is formed at the right end of the peripheral wall 44. The body 41 further has a partition wall 45.
A part of the internal space of the body 41 is partitioned by the partition wall 45 as a communication space 46. The right end of the communication space 46 is connected to the gas inlet 44a.
Most of the remaining internal space of the body 41 is formed by the other three partition walls 46a, 46b, 46c and the three gas passages 4
It is partitioned into 7a, 47b and 47c.

On the front wall 43 of the body 41, there are eight, 4 corresponding to the gas passages 47a, 47b, 47c.
One and three nozzle parts 48 are formed respectively. These nozzle portions 48 face the air chamber 16 and project toward the inlet 31 of the burner element. Further, the front wall 43 is formed with a projection 49 into which the edge of the bottom wall 11 is fitted.

The partition wall 45 of the body 41 is formed with three valve openings 45a, 45b and 45c. These valve openings 45a, 45b, 45c are for communicating the communication space 46 with the gas passages 47a, 47b, 47c, respectively. Three solenoid valves 60 are provided in a horizontal lower portion of the peripheral wall 44 of the body 41, and valve bodies 61 of these solenoid valves 60 open and close the valve openings 45a, 45b, 45c, respectively. There is.

As shown in FIG. 1, one end of a die cast passage member 65 is connected to the right end of the body 41, and is connected to the gas inlet 44a. The other end of the passage member 65 is connected to a gas pipe (not shown). In the passage member 65, a main solenoid valve 67 that opens and closes a valve port 66 formed inside the passage member 65, and an electromagnetic pressure proportional control valve 70 that controls the opening degree of another valve port 68 on the downstream side of the main solenoid valve 67. (Pressure control valve) is attached.

The pressure proportional control valve 70 has a diaphragm 71. One surface of the diaphragm 71 faces the back pressure chamber 73 and receives back pressure described later. The other surface of the diaphragm 71 receives the supply gas pressure from the gas pipe.
A valve body 75 is connected to the center of the diaphragm 71. The valve body 75 controls the opening degree of the valve port 68. The pressure proportional control valve 70 has a solenoid 76 and a rod-shaped armature 77 movably accommodated in a space surrounded by the solenoid 76. The armature 77 hits a pin 78 protruding from the valve body 75. The spring of the pressure proportional control valve 70 is omitted to simplify the drawing.

As shown in FIG. 1, the gas combustion apparatus further has a back pressure compensating means 80 and an air volume detecting means 90. The back pressure compensating means 80 includes a pressure introducing port 81a for introducing the pressure of the air chamber 16, a communication passage for transmitting the pressure, for example, a pipe 82, and the pressure transmitted from the pipe 82 for the back pressure of the pressure proportional control valve 70. Port 83 leading to chamber 73
a and. The air volume detection means 90 is configured by a pressure introduction port 91a for introducing the pressure of the air chamber 16 and a pressure introduction port 92a for introducing the pressure of the combustion chamber 17 (one end opening of a joint 92 fixed through the side wall 12). )
And a bypass pipe 93 (a bypass passage) that connects the two, and a flow velocity sensor 94 (a flow rate sensor) provided in the middle of the bypass pipe 93. As the flow velocity sensor 94, a hot wire type, a Karman vortex type, etc. are known.

Further, the gas combustion apparatus is equipped with a control unit CL having a built-in microcomputer. The control unit CL substantially controls the solenoid valves 60, 67 and 70, controls the water amount control valve of the water pipe that passes through the heat exchanger 50, and controls the rotation of the fan 20. It is equipped with control means and the like. The casing 10, nozzle holder 40, passage member 65
Or solenoid valves 60, 67, 70, control unit C
L and the like are covered with a cover CV.

The operation of the gas combustion apparatus having the above structure will be briefly described. When the main solenoid valve 67 operates and the valve port 66 opens,
Gas is supplied to the nozzle holder 40. The opening of the valve port 68 is controlled by the current flowing through the solenoid 76 of the pressure proportional control valve 70, and the gas pressure on the downstream side thereof is controlled. The gas whose pressure is controlled is the gas inlet 44 of the nozzle holder 40.
Inflow from a. By selectively operating the three solenoid valves 60 to selectively open the valve openings 45a, 45b, 45c, the gas passages 47a, 47b corresponding to the opened valve openings,
The gas flows to 47 c, and then the gas is jetted from the corresponding nozzle portion 48 and is supplied to the inlet 31 of the corresponding burner element of the gas burner 30. On the other hand, air is sent into the air chamber 16 of the casing 10 by the rotation of the fan 20, and this air is also supplied to the inlet 31 of the burner element. Gas burner element inlet 31
The gas and air supplied to the are mixed in the burner element, and injected and burned from the flame port formed on the upper surface of the burner element. The heat exchanger 50 is heated by this combustion heat.
Then, the water passing through the water distribution pipe is heated by the heat exchanger 50 to become hot water. The combustion exhaust gas that has passed through the heat exchanger 50 is discharged outdoors through a duct connected to the upper portion of the casing 10.

Next, the operation of the back pressure compensation means 80 will be described. The pressure on the downstream side of the valve port 68 of the pressure proportional control valve 70, that is, the injection pressure of the nozzle portion 48 has a linear relationship with the supply current to the solenoid 76. As described above, the air pressure in the air chamber 16 is higher than the atmospheric pressure due to the action of the fan 20, so if there is no back pressure compensation, the air pressure (back pressure) in the air chamber 16 varies with the fluctuation. However, the supply gas amount fluctuates. In order to compensate for this back pressure, the air pressure in the air chamber 16 is transmitted to the back pressure chamber 73 of the pressure proportional control valve 70 via the pressure introduction port 81a and the pipe 82. The diaphragm 71 is biased to the left in FIG. 1 in accordance with the back pressure in the back pressure chamber 73, whereby the valve body 75 moves in the same direction to increase the opening area of the valve port 68. As a result, the back pressure-compensated gas is supplied to the nozzle 4
8 to the gas burner 30.

Next, the operation of the air volume detecting means 90 will be described in detail. A part of the air sent from the fan 20 to the air chamber 16 is directly supplied to the gas burner 30 as the primary combustion air and ejected from the flame nozzle, and the rest is a secondary combustion air between the gas burner 30 and the casing 10. The combustion chamber 17 is reached through the gap and the gap between the burner elements. Therefore, a pressure difference caused by the flow resistance occurs between the air chamber 16 and the combustion chamber 17. In other words, the pressure introducing port 9
A pressure difference occurs between 1a and 92a. Due to this pressure difference, a flow of air is generated in the bypass pipe 93 from the pressure introducing port 91a toward the pressure introducing port 92a. The flow velocity of this air is measured by the flow velocity sensor 94. The flow velocity of the air becomes faster as the supply air amount per unit time sent by the rotation of the fan 20, that is, the supply air amount, becomes faster, and becomes smaller as the air amount becomes smaller. As a result, the control unit CL can detect the air volume from the measured flow velocity. Furthermore, the control unit C
At L, the rotation of the fan 20 is controlled so that the detected air volume becomes the target air volume corresponding to the supply gas pressure (supply gas volume).

Next, the features of the present invention (corresponding to claims 1 and 2) will be described in detail. As shown in FIG. 1, a communication port 100 is formed on the front wall 43 of the body 41 of the nozzle holder 40 at the end opposite to the gas inlet 44a. A part of the internal space of the body 41 is partitioned by a partition wall 101 to form a pressure equalizing chamber 102. The pressure equalizing chamber 102 has a communication port 10
It is connected to the air chamber 16 via 0. This pressure equalizing chamber 10
The partition wall 101 and the pair of flat plate-shaped walls 103 and 104 forming a part of the peripheral wall 44 form a substantially triangular shape. U-shaped recesses 103a and 104a are formed in the walls 103 and 104.
03a and 104a have tubular joints 81 and 9 respectively.
1 is fixed. One end of each of the joints 81 and 91 is arranged in the pressure equalizing chamber 102, and one end opening thereof is provided as the pressure introducing port 81a of the back pressure compensating means 80 and the pressure introducing port 91a of the air volume detecting means 90 described above.

The above features provide the following actions. That is, the pressure in the air chamber 16 pulsates due to the flow of air accompanying the rotation of the fan 20, but this pressure is absorbed in the process of being transmitted from the communication port 100 to the pressure equalizing chamber 102. Therefore, the pressure introduction ports 81a, 9
A stable pressure of the air chamber 16 is introduced into 1a, and the above-mentioned back pressure compensation of the supply gas pressure can be stably performed.
It is possible to perform stable air volume detection.

It is very important that the pressure introducing ports 81a and 91a introduce approximately the same pressure in the common pressure equalizing chamber 102. Thereby, the back pressure compensation of the supply gas pressure and the air volume detection can be performed based on the same pressure.
As a result, the ratio (air-fuel ratio) between the supply gas amount and the supply air amount can be optimally controlled with high accuracy.

In the present embodiment, a pressure wave is generated as the capacity switching solenoid valve 60 is opened and closed. This pressure wave is transmitted through the diaphragm 71 of the pressure proportional control valve 70 to the back pressure chamber 73.
From the back pressure chamber 73 to the pressure equalizing chamber 102 through the pipe 82 of the back pressure compensating means 80 and the pressure introducing port 81a, but is absorbed in the pressure equalizing chamber 102. Therefore, it is possible to prevent this pressure wave from being transmitted to the flow velocity sensor 94 of the air volume detection means 90.

In this embodiment, since the communication port 100 is formed in the substantially vertical front wall 43, it is possible to prevent water droplets from entering the communication port 100. Also,
A wall 10 having a communication port 100, a pressure equalizing chamber 102, and recesses 103a and 104a in a die-cast body 41.
Since 3, 104 are formed, it is possible to reduce the manufacturing cost without requiring cutting work or the like.

Another embodiment of the present invention will be described below with reference to the drawings. In addition, in these other embodiments, the components corresponding to those in the preceding embodiment are designated by the same reference numerals, and the description thereof will be omitted. The second embodiment shown in FIG. 3 corresponds to the invention of claim 3. In this embodiment, the casing 10 is provided with a pressure equalizing chamber 202. This pressure equalizing chamber 20
2 is formed by fixing the partition wall 201 from the side wall 12 to the bottom wall 11 of the casing 10.
This partition wall 201 is made of punching metal, for example,
It has a large number of communication ports 200, and the pressure equalizing chamber 202 communicates with the air chamber 16 via the communication ports 200. On the bottom wall 11 of the casing 10, the back pressure compensation means 8
The joint 81 of No. 0 is fixed through, and the one end opening, that is, the pressure introduction port 81 a faces the pressure equalizing chamber 202. Further, the side wall 12 of the casing 10 has a joint 91 of the air flow detecting means 90 penetratingly fixed thereto, and an opening at one end thereof, that is, a pressure introducing port 91 a faces the pressure equalizing chamber 202.

The third embodiment shown in FIG. 4 also corresponds to the invention of claim 3. In this embodiment, the casing 10
In the accommodation space 15 of the partition wall 301, a partition wall 301 that faces the bottom wall 11 is arranged in the entire area of the bottom wall 11. The peripheral edge of the partition wall 301 is fixed to the side walls 12, 13 and front and rear walls of the casing 10. Has been done. A wide pressure equalizing chamber 302 is formed by the partition wall 301 and the bottom wall 11. The partition wall 301 is formed of punching metal and has a large number of communication ports 300. Back pressure compensation means 8
0, the joints 81 and 91 of the air volume detecting means 90 are fixed through the bottom wall 11, and the pressure introducing ports 81a and 91a, which are openings at one end of the joints 81 and 91, face the common pressure equalizing chamber 302. The upper end of the fan 26 penetrates the pressure equalizing chamber 302 and the air chamber 1
We are facing 6.

The fourth embodiment shown in FIG. 5 also corresponds to the third aspect of the invention. In this embodiment, the bottom wall 11 has an opening 11
a is formed. A punching metal serving as a partition wall 401 is fixed to the upper surface of the bottom wall 11 so as to close the opening 11a, and the auxiliary cover 40 is attached to the lower surface of the bottom wall 11.
5 is fixed. Partition wall 401 and auxiliary cover 405
Thereby, the pressure equalizing chamber 402 is formed. Pressure equalizing chamber 402
Is a large number of communication ports 400 formed on the partition wall 401.
Is connected to the air chamber 16 via. Auxiliary cover 405
The pressure introducing ports 81a and 91a of the back pressure compensating means and the air volume detecting means are connected to the flat bottom portion of the.

In the second to fourth embodiments described above, the pressure introducing ports 81a and 91a of the back pressure compensating means and the air volume detecting means.
Are connected to a common pressure equalizing chamber 202, 302, 402, and the operational effects obtained thereby are substantially the same as those in the first embodiment, so detailed description will be omitted.

The fifth embodiment shown in FIG. 6 corresponds to the invention of claim 4. In this embodiment, the casing 1
An auxiliary casing 500 having a small volume apart from 0 is used. The internal space of the auxiliary casing 500 is provided as the second pressure equalizing chamber 502. This pressure equalizing chamber 502
The pressure introducing ports 81a and 91a of the back pressure compensating means and the air volume detecting means are respectively connected to. The auxiliary casing 500 is connected to a pressure equalizing chamber 202 having the same structure as that of the second embodiment via a communication pipe 505. In this embodiment, the pressure equalizing chamber 202 absorbs the pulsation of the air chamber 16.
Further, in the pressure equalizing chamber 502, the pressure wave from the back pressure chamber of the pressure proportional control valve is absorbed, and this pressure wave can be prevented from being transmitted to the flow velocity sensor of the air volume detecting means. Therefore, stable air flow detection can be ensured.

The sixth embodiment shown in FIG. 7 corresponds to the inventions of claims 1 and 3. In this embodiment, a T-shaped pipe joint 600 is used, and one pipe portion 601 of this joint 600 is fixed through the side wall 12 of the casing 10. The other two pipe portions 602 and 603 are provided with a pipe 82 of the back pressure compensating means 80 and an air volume detecting means 90, respectively.
The bypass pipe 93 of is connected. Therefore,
One end opening 601a of the pipe portion 601 facing the pressure equalizing chamber 202
Serves as a common pressure introduction port for the back pressure compensating means 80 and the air volume detecting means 90. In this embodiment, the pressure wave described above cannot be absorbed.

In the fifth embodiment of FIG. 6, the partition wall 20
1, the pressure equalizing chamber 202 may be omitted. In this case, claim 5
It becomes an embodiment corresponding to the invention of. Further, in the sixth embodiment of FIG. 7, the partition wall 201 and the pressure equalizing chamber 202 may be omitted. In this case, the embodiment corresponds to the invention of claim 6. Further, the auxiliary casing 500 and the joint 600 of the fifth and sixth embodiments may be connected to the pressure equalizing chambers 102, 302 and 402 of the first, third and fourth embodiments.

In the above embodiment, the flow velocity sensor 85 is provided as the air flow sensor in the bypass passage, but a differential pressure sensor may be provided instead of this flow velocity sensor. In this case, the air flow in the bypass passage disappears, but the amount of air sent from the fan per unit time can be calculated by detecting the pressure difference between the upper and lower communication ports. The other pressure introducing port of the air amount detecting means may be provided not in the combustion chamber but in the exhaust system on the downstream side of the heat exchanger. Further, the fan may be provided above the heat exchanger to supply air to the air chamber by suction.

[0033]

As described above, according to the present invention, the pressure information of the air chamber introduced through the pressure introducing port of the back pressure compensating means and the air chamber introduced through the pressure introducing port of the air volume detecting means. Therefore, the air-fuel ratio can be optimally controlled with high accuracy. Further, since the pressure pulsation of the air chamber is absorbed in the pressure equalizing chamber, the back pressure compensation and the supply air amount can be stabilized. According to the second aspect of the invention, since the communication port and the pressure equalizing chamber are formed in the nozzle holder made of die casting, the manufacturing cost can be reduced. According to the invention of claim 3, the pressure equalizing chamber is provided in the casing, and the installation position of the pressure equalizing chamber can be relatively freely selected. In the invention of claim 4, the pressure fluctuation of the air chamber can be absorbed in the first pressure equalizing chamber, and the pressure wave from the pressure control valve can be absorbed in the second pressure equalizing chamber. it can. According to the fifth aspect of the invention, since the pressure equalizing chamber is separated from the casing, the selection range of the installation position of the pressure equalizing chamber and the structure of the back pressure compensating means and the air volume detecting means is widened. According to the invention of claim 6, as in claim 1, the air-fuel ratio can be optimally controlled with high accuracy.

[Brief description of drawings]

FIG. 1 is a rear view showing a gas combustion apparatus according to a first embodiment of the present invention with a partial cross section and a back plate of a nozzle holder removed.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is a rear view showing a partial cross section of a gas combustion apparatus according to a second embodiment of the present invention.

FIG. 4 is a rear view showing a partial cross section of a gas combustion apparatus according to a third embodiment of the present invention.

FIG. 5 is a cross-sectional view of essential parts of a fourth embodiment of the present invention.

FIG. 6 is a cross-sectional view of essential parts of a fifth embodiment of the present invention.

FIG. 7 is a cross-sectional view of essential parts of a sixth embodiment of the present invention.

[Explanation of symbols]

 10 ... Casing 15 ... Storage space 16 ... Air chamber 17 ... Combustion chamber 20 ... Fan 30 ... Gas burner 40 ... Nozzle holder 41 ... Body 50 ... Heat exchanger 68 ... Valve port 70 ... Electromagnetic pressure proportional control valve (pressure control valve) 80 Back pressure compensator 90 Air amount detector 81a, 91a Pressure introduction port 94 Flow velocity sensor (differential pressure sensor) 100, 200, 300, 400 Communication port 102, 202, 302, 402 ... Pressure equalizing chamber 502 2 pressure equalizing chamber 505 ... communication pipe 601a ... common pressure introducing port

Claims (6)

[Claims] 1. A gas burner which is housed in a housing space of (a) casing and (b) casing and divides the housing space into a lower air chamber and an upper combustion chamber, and (c) air is supplied to the air chamber. Fan, (d) a nozzle holder having a nozzle part for supplying gas to the gas burner, and (e) a solenoid controlling the gas pressure on the downstream side of the valve port connected to the nozzle part of the nozzle holder, and by extension the nozzle. A pressure control valve for controlling the amount of supply gas from the section, and (f) back pressure compensating means for compensating the back pressure of the supply gas pressure by supplying the pressure of the air chamber as a back pressure to the pressure control valve. ,
(G) An air volume detecting means for detecting an air volume to the air chamber based on a difference between the pressure of the air chamber and the pressure of the combustion chamber or a downstream side thereof, and (h) an air volume detected by the air volume detecting means. So that the air flow rate corresponds to the supply gas volume, the gas combustion apparatus is provided with an air flow rate control means for controlling the rotation of the fan, and a pressure equalizing chamber connected to the air chamber via a communication port is provided. A gas combustion apparatus, wherein the pressure introducing port of the back pressure compensating means and the pressure introducing port of the air flow detecting means are connected to the pressure equalizing chamber. 2. The nozzle holder is provided with a body formed by die casting, and the body is provided with the pressure equalizing chamber and the communication port connecting the pressure equalizing chamber and the air chamber. The gas combustion device according to claim 1. 3. The gas combustion apparatus according to claim 1, wherein the pressure equalizing chamber is provided in the casing. 4. A second pressure-equalizing chamber is provided further away from the casing, and the second pressure-equalizing chamber is connected to the first pressure-equalizing chamber via a communication pipe, and the second pressure-equalizing chamber is connected to the second pressure equalizing chamber. The gas combustion apparatus according to any one of claims 1 to 3, wherein the pressure introducing port of the back pressure compensating means and the pressure introducing port of the air volume detecting means are connected to each other. 5. The gas combustion apparatus according to claim 1, wherein the pressure equalizing chamber is arranged apart from the casing, and is connected to the air chamber via a communication pipe. 6. A gas burner which is housed in a housing space of (a) casing and (b) casing and divides the housing space into a lower air chamber and an upper combustion chamber, and (c) air is supplied to the air chamber. Fan, (d) a nozzle holder having a nozzle part for supplying gas to the gas burner, and (e) a solenoid controlling the gas pressure on the downstream side of the valve port connected to the nozzle part of the nozzle holder, and by extension the nozzle. A pressure control valve for controlling the amount of supply gas from the section, and (f) back pressure compensating means for compensating the back pressure of the supply gas pressure by supplying the pressure of the air chamber as a back pressure to the pressure control valve. ,
(G) An air volume detecting means for detecting an air volume to the air chamber based on a difference between the pressure of the air chamber and the pressure of the combustion chamber or a downstream side thereof, and (h) an air volume detected by the air volume detecting means. In a gas combustion apparatus comprising: an air volume control means for controlling the rotation of a fan so that the air volume corresponds to the supply gas volume, a back pressure compensating means and an air volume detection device are provided at predetermined locations in the air chamber. A gas combustion device, characterized in that a common pressure introduction port of the means is connected.