JPH0434047B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a combustion device improved to improve the mixing of fuel and air.

[Prior art] In gas combustion devices, even when the same amount of combustion is obtained, the amount of fuel gas supplied varies depending on the type of gas.
Furthermore, if fuel gas and air are not mixed sufficiently, stable combustion cannot be obtained, and especially in combustion equipment that performs all primary air combustion, ignition failure or misfire may occur.

For this reason, the inventors of the present application installed a fuel dispersion plate having a plurality of fuel injection ports in order to easily obtain a fuel supply amount corresponding to the gas type and to ensure sufficient mixing. A fuel device has already been proposed that is arranged to cover the opening of a fuel supply pipe that opens into an air passage, and that distributes and supplies fuel from each fuel jet port.

[Problems to be Solved by the Invention] However, in a fuel device that injects fuel using a fuel distribution plate, the pressure inside the fuel distribution chamber changes depending on the amount of gas supplied, and the fuel injection port is connected to the fuel distribution plate. The fuel gas is formed almost perpendicular to the fuel nozzle and concentrates from around the fuel nozzle toward the fuel nozzle, so depending on the pressure and the amount of gas passing through, the gas may become turbulent when ejected, causing a harsh sound. There is a problem in that it may generate a lot of noise.

An object of the present invention is to prevent noise caused by fuel jetting in a combustion device that jets fuel from a fuel jet port provided in a fuel distribution plate.

[Means for Solving the Problems] The present invention is provided so as to cover an opening of a fuel supply pipe communicating with an air supply passage that guides combustion air to a burner, and distributes fuel to be supplied to the burner. In the combustion device, the combustion apparatus includes a fuel dispersion plate that forms a fuel distribution chamber to control the fuel distribution and has a plurality of fuel injection ports for ejecting fuel into the air supply passage. The technical means is that a fuel guiding member is provided that guides the fuel supplied into the room to the plurality of fuel jet ports.

[Function] In the present invention, since the opening of the fuel supply pipe is covered by the fuel jet plate, the fuel supplied by the fuel supply pipe is discharged from the plurality of fuel jet ports of the fuel supply pipe. supplied to the road.

These fuel injection ports are equipped with fuel guide members, so that the fuel in the fuel distribution chamber formed by the fuel distribution plate is guided to each fuel injection port by the fuel guide member, and is distributed between each fuel injection port. gush.

[Effects of the Invention] In the present invention, since fuel is ejected from the plurality of fuel jet ports of the fuel distribution plate, it is possible to improve mixing with air.

Further, the fuel injection port is provided with a fuel guide member, and the fuel in the fuel distribution chamber is guided to the fuel injection port by the fuel guide member, so that the fuel is smoothly ejected. Therefore, even if there is a change in the pressure inside the fuel distribution chamber or a change in the amount of ejection, vortices and vibrations accompanying the ejection are less likely to occur, and no harsh noise is generated.

[Example] Next, the present invention will be explained based on examples.

The gas water heater 1 shown in Fig. 2 is equipped with a high-efficiency combustor 2 that is compact and achieves low noise through all primary air combustion.
0, and a supply section 20 that supplies a mixture of fuel gas and air to the combustion section 10.The supply section 20 is equipped with an air supply case 31 that guides air and fuel gas. A heat exchanger 50 is provided, and the entire heat exchanger 50 is housed in a water heater casing (not shown).

In the combustion section 10, a burner plate 12 in the shape of a flat plate made of ceramic and having a large number of flame ports is disposed at the opening at the lower end of a cylindrical combustion case 11, and an exhaust pan 13 is arranged at the opening at the upper end of the combustion case 11. A combustion chamber 14 is formed by the combustion case 11, and an exhaust passage 15 is formed by the exhaust pan 13.

An exhaust port 16 is formed in the exhaust pan 13 to exhaust combustion gas generated in the combustion chamber 14 to the outside. In addition, glass wool 13a is provided on the opposing surfaces inside the exhaust pan 13 to prevent air vibrations from being repeatedly reflected.
is formed and changes its reflection direction. Here, the inclined surface 13b is formed by fixing several layers of glass wool 13a with an inorganic binder.

A water tube type heat exchanger 50 connected to a water supply source such as a water supply is provided above the combustion case 11, and heats water passing through the interior.

In addition, two sparker electrodes 1 for ignition are provided near the burner plate 12 in the combustion case 11.
7. Flame rod 18 for detecting ignition;
Each is provided with a thermocouple 19 for detecting combustion temperature to correct the air-fuel ratio.

The supply unit 20 includes a mixing case 21 provided below the combustion case 11 and covering the burner plate 12.
and a blower case 22 provided in communication with an inlet 21a at the lower end of the mixing case 21.

The mixing case 21 disperses the air-fuel mixture supplied from the inlet 21a and guides it to the combustion section 10.
A rectifying plate 24 is provided inside the mixing case 21, and the plurality of holes 24a of the rectifying plate 24 disperse and rectify the air-fuel mixture.

As shown in FIGS. 1 and 3, the blower case 22 includes a scroll casing 22a having an approximately short cylindrical shape with one bottom open, and a flat plate portion 23 provided to close the opening of the scroll casing 22a. The blower case 22 is equipped with a blower 25.

An air outlet 22b is provided on the outer periphery of the scroll casing 22a, communicating with the inlet 21a of the mixing case 21 and forming a constant angle with respect to the center of the scroll casing 22a.

The flat plate part 23 is provided with a bellmouth-shaped suction port 23a at its center that protrudes toward the scroll casing 22a side, and according to the rotational state of the blower 25, air and fuel gas are sucked in from the suction port 23a, and the air and fuel gas are sucked in from the suction port 23a. It blows out from 22b.

A fuel ejection pipe 23b for ejecting fuel gas supplied from the fuel pipe 60 is formed integrally with the flat plate part 23 on the surface of the flat plate part 23, which is the outside of the blower case 22. The spout ports 23c are provided in one row.

Here, in order to improve the mixing, among the jet ports 23c arranged in a row, the diameter of the jet port 23c1, which is the most upstream side with respect to the blow port 22b of the blower case 22 when the blower 25 is activated, is different from that of the other jet ports 23c. It is made larger than the diameter of the spout 23c.

The blower 25 includes an impeller 25a inside the blower case 22, and rotates the impeller 25a by a motor 25b provided outside the blower case 22, sucks air and fuel gas through the intake port 23a, and blows the air and fuel gas. The air-fuel mixture is blown out from the outlet 22b and is supplied to the combustion section 10 via the mixing case 21.

Here, the motor 25b is controlled according to the required combustion amount, and the impeller 25a is rotated to the left in FIG. 2 at a rotation speed according to the control state.

An air supply case 31 is installed in the blower case 22 so as to cover the intake port 23a and the fuel injection pipe 23b.
is provided.

The air supply case 31 has an equivalent volume V ₂ , a passage equivalent length l 2 , and an equivalent passage length l _{2 in order to match the natural frequency f 2 of} the supply section 20 with the natural frequency f 1 based on the acoustic characteristics of the combustion section ₁₀ . This is provided to ensure a cross-sectional area _S2 .

The air supply case 31 has a substantially rectangular parallelepiped shape that is open in two directions, with one open part facing the flat plate part 23 of the blower case 22 and the other open part facing the air supply port 31a.
An air supply path 32 that opens downward in the figure and is hermetically joined to the blower case 22 and guides combustion air sucked in from the air supply port 31a and fuel gas ejected into the air supply case 31 to the suction port 23a. Form.

A fuel supply port 31c is provided through one side wall 31b of the air supply case 31 to be connected to the fuel pipe 60a.

Further, each side wall 31b, 31d of the air supply case 31 has a plurality of through holes 31e, 31, which pass through the inside and outside of the air supply case 31, as shown in FIG.
f are provided separately.

These through holes 31e and 31f are connected to the combustion section 10.
The combustion chamber 1 is added to the supply section 20 so that a damper 38, which will be described later, is difficult to close during ignition.
This is provided in order to release the ignition pressure in 4.

Inside the air supply case 31, a fuel distribution plate 33 is disposed at an angle so as to cover the fuel supply port 31c and a part of the inside of the air supply case 31.

The fuel distribution plate 33 has a step in the middle, is airtightly fixed to the inside of the air supply case 31 by packing 34, and forms an inclined surface for smoothly guiding the air-fuel mixture to the intake port 23a. air case 31
and the fuel distribution plate 33 form a fuel distribution chamber 35.

The fuel distribution plate 33 is provided with a plurality of fuel injection ports 33a distributed in a row, and the blower case 2
On the most upstream side of the second outlet 22b, there are several fuel outlets 33b separated from the fuel outlet 33a.
is provided.

As a result, more fuel gas supplied into the fuel distribution chamber 35 is ejected from the fuel ejection port 33b toward the upstream side of the air supply path 32, so that efficient mixing is performed.

This fuel dispersion plate 33 has fuel injection ports 33a, 33b that have different sizes and numbers depending on the type of gas used, and can easily be adapted to different gas types. and air are mixed properly. Note that when the fuel distribution plate 33 is replaced depending on the type of gas, the flat plate portion 23 integrated with the fuel injection pipe 23b is also replaced at the same time.

On the fuel distribution chamber 35 side of the fuel dispersion plate 33, a fuel guide plate 33c for guiding the fuel gas to the fuel nozzle 33a is provided along the end of the fuel nozzle 33a. about 60 against the side
It is fixed by spot welding at a degree angle.

As a result, the fuel gas is guided smoothly when passing through the fuel nozzle 33a, and the fuel gas is less disturbed when passing through the fuel nozzle 33a.

Therefore, even if the amount of fuel gas supplied into the fuel distribution chamber 35 or the gas pressure changes, there will be no resonance of the fuel gas, and abnormal noises can be eliminated.

In the air supply passage 32 on the upstream side of the air supply case 31, the width of the air supply passage 32 is gradually reduced toward the fuel injection pipe 23b so that the air passing therethrough is not disturbed. An arranged aperture plate 36 is provided.

Therefore, the throttle plate 36 forms a ventilate that reduces the cross-sectional area of the air supply passage 32 and once restricts the air passing through the air supply passage 32, so that each injection port 23c of the fuel injection pipe 23b and the fuel Dispersion plate 3
The fuel gas ejected from the three fuel ejection ports 33a, 33b can be mixed well with air.

A damper 38 swingably supported by a shaft 37 is provided in the air supply case 31 near the air supply port 31a. The damper 38 is provided to change the equivalent cross-sectional area S ₂ of the supply section 20 by its swinging motion. , and changes the equivalent cross-sectional area S ₂ .
As a result, when the combustion amount of the combustor 2 is large and the amount of air blown is large, the damper 38 is opened and the equivalent cross-sectional area _S2 becomes large, and when the amount of combustion is small and the amount of air blown is small, the damper 38 is opened. The opening degree of is reduced, reducing the equivalent cross-sectional area _S2 .

The tip 38 on the outer circumferential side when the damper 38 swings
In a part of a, when the equivalent cross-sectional area S ₂ of the supply section 20 becomes the minimum and exhibits the minimum opening degree, the air supply case 3
A protrusion 38b that abuts on the inner wall 31g of 1 is formed. As a result, the equivalent cross-sectional area S ₂ of the supply section 20
Even when the tip 3 of the damper 38
A suitable gap is formed between the air supply case 8a and the inner wall 31g of the air supply case 31, so that the necessary amount of air can be supplied.

When the equivalent cross-sectional area S ₂ of the supply section 20 is the minimum, the damper 38 has this protrusion 38b in contact with the inner wall 31g of the air supply case 31, as shown in FIG. When the cross-sectional area S ₂ becomes the maximum and exhibits the maximum opening, the damper 38
As shown by the two-dot chain line, it is stabilized with an appropriate distance from the diaphragm plate 36.

Further, curved portions 38c and 38d are formed at both ends of the damper 38 in the axial direction to guide the air sucked in and pushing up the damper 38 inward.
These curved portions 38c and 38d prevent the air hitting the damper 38 from escaping to the outside of the curved portions 38c and 38d, making it difficult for dust and the like to adhere to the inner wall surface of the air supply case 31.

Further, bearing portions 38e and 38f of the damper 38
is provided on the flat plate portion 23 side of the blower case 22 with respect to the damper 38 that receives wind pressure, so that a horizontal distance between the center of gravity of the damper 38 and the shaft 37 can be secured;
The rotational moment due to the weight of the damper 38 can always bias the damper 38 in the closed state, and even when the damper 38 is at its maximum opening, airflow can pass between the damper 38 and the throttle plate 36. Therefore, the damper 38 can be stabilized in each case.

Upstream of the inner wall 31g of the air supply case 31 against which the projection 38b of the damper 38 comes into contact, a protrusion 39 that protrudes toward the inside of the air supply case 31 is provided to change the direction of the sucked air flow. Due to this protrusion 39, when the damper 38 is in the closed state, air from the air supply port 31a is difficult to hit the 1/3 part from the tip 38a of the damper 38, and when it is fully open, the entire damper 38 is Because of the air,
The opening degree of the damper 38 can be made proportional to the combustion amount.

The shaft 37 is loosely supported at both ends by a cylindrical bearing member 40 made of fluororesin.
0 is fitted and supported within a fitting groove formed in the flat plate portion 23 and the air supply case 31.

A filter 41 made of a metal mesh is provided in the air supply port 31a.

Fuel pipe 60a that guides fuel to fuel supply port 31c
is connected to the fuel injection pipe 23b, and is connected to the fuel injection pipe 23b.
3b is connected to a fuel pipe 60.

A proportional control valve (not shown) is provided upstream of the fuel pipe 60 and is controlled together with the blower 25 according to the required combustion amount. A regulated fuel gas is provided.

The heat exchanger 50 is connected to a water pipe (not shown) that leads water from the water supply, and the water pipe upstream of the heat exchanger 50 is equipped with a water flow control valve, a water flow sensor, and an inlet water temperature thermistor from the upstream side. A hot water temperature thermistor is provided downstream of the heat exchanger 50, and a water faucet (not shown) that is operated by the user is provided at the downstream end.

The gas water heater 1 having the above configuration is controlled by a control device and operates as follows.

When the user sets the hot water temperature using the controller and operates the faucet to start hot water supply, the combustor 2 starts combustion in a predetermined sequence, and the water flows into the heat exchanger 50 using the water flow control valve. The inflow amount of water is adjusted.

When the blower 25 is controlled to a slow ignition rotational speed and air is sucked in from the air supply port 31a by its operation, the damper 38 changes its opening degree to the opening degree for ignition according to the amount of air supply.

On the other hand, fuel gas whose supply amount is adjusted for slow ignition by the proportional control valve is ejected from the injection port 23c of the fuel injection pipe 23b and the fuel injection ports 33a, 33b of the fuel distribution plate 33. is ejected over a wide area and mixes well with the air.

At this time, within the fuel distribution chamber 35, the fuel gas is smoothly directed to the fuel injection port 33 by the fuel guide plate 33c.
a, resulting in less turbulence in the fuel gas. Therefore, abnormal noises associated with the ejection of fuel gas are less likely to occur.

When spark discharge is performed at the sparker electrode 17 as an ignition operation, the air-fuel mixture supplied into the combustion chamber 14 is ignited. At this time, the ignition pressure generates a force that urges the damper 38 of the supply section 20 in the closing direction, but the ignition pressure is released through the through holes 31e and 31f provided in the air supply case 31. Therefore, the opening degree of the damper 38 can be maintained approximately at the opening degree corresponding to the combustion amount, so that no abnormal noise is generated.

Thereafter, the damper 38 swings to each position as follows depending on the amount of air sucked in.

When the amount of combustion in the combustor 2 is small and the rotational speed of the blower 25 is between N1 and N2 in FIG. exhibits.

The amount of combustion is increased, and the rotation speed of the blower 25 is increased.
Between N2 and N3, the damper 38 exhibits an opening degree that corresponds to the blower.

When the combustion amount is further increased and the rotational speed of the blower 25 is between N3 and N4, the damper 38 is fully opened.

Therefore, between the minimum opening degree and the maximum opening degree, the equivalent cross-sectional area S ₂ of the supply section 20 changes depending on the combustion amount, so the natural frequency f of the combustion section 10 changes depending on the combustion amount. ₁ , the natural frequency f ₂ of the supply section 20 changes in the same way, so that even if the combustion amount changes, noise can be reduced. Note that at this time, the combustion amount of the combustor 2 changes as shown by the solid line B.

Further, the amount of fuel gas supplied according to the control amount of the proportional control valve is adjusted to the inside of the fuel injection pipe 23b and to the fuel distribution chamber 3.
5 and jets out from each spout. At this time, within the fuel distribution chamber 35, the fuel gas is guided to the fuel injection port 33a by the fuel guide plate 33c, so that the fuel gas is smoothly ejected even if the fuel supply amount changes. Therefore, no abnormal noise is generated.

In this embodiment, the fuel guide plate 33c is not provided for the fuel jet ports 33b, but this is because the pressure applied to each fuel jet port 33a, 33b by the air flow passing through the air supply path 32 is different. Therefore, the fuel injection amount and pressure from each fuel injection port 33a, 33b are different, and the fuel injection port 33
This is because abnormal noise is likely to occur only in case a, and the best fuel guide plate may be provided depending on each combustion device.

As described above, in this example, even if the fuel supply amount changes, no abnormal noise is generated due to fuel injection, and no abnormal sound or noise is generated during ignition or steady combustion. It can be a low-noise combustion device.

In the above embodiment, the fixed angle of the fuel guide plate is approximately 60
degrees, but this angle may be 90 degrees or any other angle.

In this embodiment, a fuel guide plate is used as the fuel guide member, but the shape of the inside of the air supply case may be changed to form an inner wall along the fuel injection port.

[Brief explanation of drawings]

1 to 4 show a gas water heater according to an embodiment of the present invention, FIG. 1 is a side sectional view of the supply section, FIG. 2 is a front view showing the schematic structure of the gas water heater, and FIG. FIG. 4 is an exploded perspective view showing the configuration of the supply section, and FIG. 4 is an exploded perspective view showing the inside of the air supply case. FIG. 5 is a characteristic diagram showing the amount of combustion air supplied by the supply section of the present invention and the opening degree of the damper. In the figure, 12...burner plate (burner), 3
1c... fuel supply port (opening), 32... air supply path,
33...Fuel distribution plate, 33a...Fuel injection port (multiple fuel injection ports), 33c...Fuel guide plate (fuel guide member), 35...Fuel distribution chamber, 60a...Fuel pipe (fuel supply pipe) .

Claims (1)

[Scope of Claims] 1. Provided to cover the opening of the fuel supply pipe communicating with the air supply path that guides combustion air to the burner,
A combustion device comprising a fuel distribution plate forming a fuel distribution chamber for distributing fuel to be supplied to the burner and having a plurality of fuel injection ports for ejecting fuel into the air supply path, A combustion device characterized in that the fuel injection ports are provided with a fuel guiding member that guides the fuel supplied into the fuel distribution chamber to the plurality of fuel injection ports.