JPH02150610A - Combustion apparatus - Google Patents

Abstract

PURPOSE:To prevent the occurrence of noise accompanying fuel jetting by providing a plurality of fuel jet ports with a fuel guide member whereby a fuel supplied into a fuel distribution chamber is led to the fuel jet ports in a plurality. CONSTITUTION:A plurality of fuel jet ports 33a are provided in one line and in a scattered manner in a fuel dispersion plate 33. Moreover, several fuel jet ports 33b are provided on the most upstream side of a diffuser 22b of a fan case 22. A fuel gas supplied into a fuel distribution chamber 35 is jetted more on the upper stream side of an air feed path 32 from the fuel jet ports 33b, and therefore efficient mixing is conducted. On the fuel distribution chamber 35 side of the fuel dispersion plate 33, a fuel guide plate 33c for leading the fuel gas to the fuel jet ports 33a is fixed along the end parts of these ports 33a at an angle of about 60 degrees to the fuel jet ports 33a side of the fuel dispersion plate 33. The fuel gas is guided smoothly when it passes through the fuel jet ports 33a, and the turbulence thereof on the occasion of its passing through the fuel jet ports 33a is reduced. Thus, resonant, extraordinary sounds of the fuel gas can be eliminated even when the supply amount of the fuel gas or the pressure thereof varies.

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.

L 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 gas type, and if the fuel gas and air are not mixed sufficiently, stable combustion may not be achieved. Especially in combustion equipment that performs all-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 combustion 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 combustion device that measures fuel injection 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 be turbulent when ejected, causing a harsh noise. There is a problem that this may occur.

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.

[Operation] 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 supplied to the air supply path from the plurality of fuel jet ports of the fuel supply pipe. Ru.

Since these fuel injection ports are equipped with fuel guide members, 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 ejected respectively.

[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 total air combustion. The supply section 20 is equipped with an air supply case 31 that guides the air and the fuel gas, and a heat exchanger 50 is provided in the combustion section 10. The whole is housed in a water heater casing (not shown).

In the combustion section 10, a burner plate 12 in the shape of a flat ceramic plate having a large number of flame ports is disposed in the opening at the lower end of a cylindrical combustion case 11, and the openings at the ends of the combustion case 11 are arranged as exhaust pans. 13, the combustion chamber 14 is covered by the combustion case 11, and the exhaust path 1 is covered by the exhaust pan 13.
5 are formed respectively.

The exhaust pan 13 contains combustion gas generated in the combustion chamber 14.
An exhaust port 16 is formed to discharge the gas to the outside. Also,
Glass wool 13a is provided on the opposing inner surfaces of the exhaust pan 13 in order to prevent the reflection of air vibrations from turning around.
An inclined surface 13b is formed by changing the direction of reflection. Here, the inclined surface 13b is formed by fixing several layers of glass wool 13a with an inorganic binder.

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

Also, near the burner plate 12 in the combustion case 11, there are two sparker electrodes 17 for ignition, a flame rod 18 for detecting ignition, and a thermocouple 19 for detecting combustion temperature for correcting the air-fuel ratio. are provided for each.

The supply section 20 is located below the combustion case 11 (burner plate).
It consists of a mixing case 21 provided to cover the mixing case 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, and a plurality of holes 2 of the rectifying plate 24
4a performs dispersion and rectification of 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 sink 22a. The blower case 22 is equipped with a blower 25.

The scroll casing 22 is connected to the inlet 21a of the mixing case 21 on the outer circumference of the scroll casing 22a.
An air outlet 22b is provided which forms a certain angle with the center direction of the air outlet 22b.

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

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

Here, in order to improve the mixing, when the blower 25 is operated, the blower case 2 is
The outlet 2 which is the most upstream side with respect to the outlet 22b of the outlet 2
The diameter of the spout 3c1 is larger than the diameter of the other jet ports 23c.

The blower 25 has an impeller 25a inside the blower case 22.
A motor 2 provided on the outside of the blower case 22
5b rotates the impeller 25a, sucks in air and fuel gas from the inlet 23a, blows it out from the outlet 22b, and sends the air-fuel mixture to the combustion section 1 via the mixing case 21.
Supply to o.

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 provided in the blower case 22 so as to cover the intake port 23a and the fuel injection pipe 23b.

The air supply case 31 has an equivalent volume V2, an equivalent passage length p2, and an equivalent cross-sectional area s2 in order to match the natural frequency f2 of the supply section 2o with the natural frequency f1 based on the acoustic characteristics of the combustion section 1o. It was established to ensure that

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 opening downward in the figure as an air supply port 31a. It is hermetically joined to the blower case 22 and has an air supply port 31a.
An air supply path 32 is formed that guides the combustion air sucked in from the air supply case 31 and the fuel gas ejected into the air supply case 31 to the suction port 23a.

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, on each side wall 31b, 31d of the air supply case 31, a fourth
As shown in the figure, a plurality of through holes 31e and 31f are provided in a distributed manner through the inside and outside of the air supply case 31, respectively.

These through holes 31e and 31f are formed so that a damper 38, which will be described later, is difficult to close when ignition occurs in the combustion section 10.
This is provided to release the ignition pressure within the combustion chamber 14 that is applied to the supply section 20.

A fuel distribution plate 33 is provided inside the air supply case 31 so as to cover the fuel supply port 31c and a part of the inside of the air supply case 31.
are arranged at an angle.

The fuel distribution plate 33 has a stepped portion in the middle, and the backing 3
4 is airtightly fixed to the inside of the air supply case 31 to form an inclined surface for smoothly guiding the air-fuel mixture to the intake port 23a, and a fuel distribution chamber 35 is formed by the air supply case 31 and the fuel distribution plate 33. do.

The fuel dispersion plate 33 is provided with a plurality of fuel injection ports 33a distributed in a row, and the fuel injection ports 22 of the blower case 22 are provided with a plurality of fuel injection ports 33a.
Several fuel jet ports 33b are provided on the most upstream side with respect to b, separated from the fuel jet port 33a.

As a result, the fuel gas supplied into the fuel distribution chamber 35 is ejected from the fuel injection port 33b as much as possible on 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 handle different gas types, and can control the fuel supply amount and fuel gas. 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.

A fuel injection port 3 is provided on the fuel distribution chamber 35 side of the fuel distribution plate 33.
A fuel guide plate 33c for guiding the fuel gas to the fuel injection port 33a is fixed by spot welding along the end of the fuel distribution plate 33 at an angle of about 60 degrees to the fuel injection port 33a side of the fuel distribution plate 33. ing.

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 as not to cause turbulence to the air passing through. A diaphragm plate 36 is provided which is arranged so as to

Therefore, since the throttle plate 36 forms a venturi that reduces the cross-sectional area of the air supply passage 32 and once restricts the air passing through the air supply passage 32, the throttle plate 36 reduces the cross-sectional area of the air supply passage 32 and once restricts the air passing through the air supply passage 32. Each fuel jet port 33a, 3 of the plate 33
The fuel gas ejected from 3b can be mixed well with air.

A damper 38 that is 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 S2 of the supply section 20 by its swinging.
8 operates in accordance with the wind pressure of air sucked in from the air supply port 31a with the operation of the blower 25, and changes the equivalent cross-sectional area S2. 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. becomes smaller, and the equivalent cross-sectional area S2
Make smaller.

When the damper 38 swings, a portion of the tip 38a on the outer circumferential side comes into contact with the inner wall 31g of the air supply case 31 when the equivalent cross-sectional area S2 of the supply section 20 becomes the minimum and exhibits the minimum opening degree. A protrusion 38b is formed. As a result, even when the equivalent cross-sectional area S2 of the supply section 20 is minimized, an appropriate gap is formed between the tip 38a of the damper 38 and the inner wall 31g of the air supply case 31, and the necessary amount of air is can be supplied.

When the equivalent cross-sectional area S2 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 area S2 becomes the maximum and exhibits the maximum opening degree, the damper 38 moves toward the diaphragm plate 36 as shown by the two-dot chain line.
It stabilizes after a moderate interval.

Further, at both ends of the damper 38 in the axial direction, there are curved portions 3 for guiding the air sucked in and pushing up the damper 38 inward.
8c and 38d are formed.

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, since the bearing parts 38e and 38f of the damper 38 are provided on the flat plate part 23 side of the blower case 22 with respect to the damper 38 which receives wind pressure, the horizontal distance between the center of gravity of the damper 38 and the shaft 37 can be secured, and the damper 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,
Since the air flow can pass between the damper 38 and the diaphragm plate 36, the damper 38 can be stabilized in each case.

Upstream of the inner wall 31g of the air supply case 31 with which the protrusion 38b of the damper 38 comes into contact, there is a protrusion 3 that protrudes toward the inside of the air supply case 31 in order to change the direction of the sucked air flow.
9 is provided. This protrusion 39 allows the damper 3
8 is in the closed state, the air from the air supply port 31a hits 1/3 of the tip 38a of the damper 38.
When the damper 38 is fully opened, air hits the entire damper 38, so 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, and the bearing member 40 is connected to the flat plate portion 2.
3 and a fitting groove formed in the air supply case 31.

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

A fuel pipe 60a that guides fuel to the fuel supply port 31c is connected to a fuel jet pipe 23b, and the fuel jet pipe 23b is connected to the fuel pipe 60.
is connected to.

The soil and flow of the fuel pipe 60 are supplied with air 11 according to the required combustion amount.
A proportional control valve (not shown) that is controlled together with the proportional control valve 25 is provided, and fuel gas whose supply amount is adjusted by the proportional control valve is supplied to the fuel injection pipe 23b and the fuel supply port 31c.

The heat exchanger 50 is connected to a wood pipe (not shown) that leads water from the water supply, and the water pipe 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. Further, 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 flow control valve starts supplying water into the heat exchanger 50. The amount of inflow is adjusted.

When the blower 25 is controlled to a slow ignition speed and air is sucked in from the air supply port 31a by its operation, the damper 3
8 changes the 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 ejection port 23c of the fuel injection pipe 23b and the fuel ejection ports 33a and 33b of the fuel distribution plate 33, and the fuel gas is wide. It is sprayed over a wide area and mixes well with the air.

At this time, within the fuel distribution chamber 35, the fuel gas is smoothly guided to the fuel injection port 33a by the fuel guide plate 33c, and there is little disturbance 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.
Since the ignition pressure can be released through the through holes 31e and 31f provided in the damper 38, 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.

The combustion amount of the combustor 2 is small, and the rotation speed of the blower 25 is the fifth.
In the figure, between N1 and N2, the damper 38 comes into contact with the inner wall 31g and exhibits an opening state where the opening area is the minimum, as shown by the broken line A.

When the combustion amount is increased and the rotational speed of the blower 25 is between N=162 and N3, the damper 38 exhibits an opening degree corresponding to the amount of air blown.

The combustion amount is further increased, and the rotation speed of the blower 25 is increased to N.
Between 3 and N4, the damper 38 is fully open.

Therefore, between the minimum opening degree and the maximum opening degree, the equivalent cross-sectional area S2 of the supply section 20 changes depending on the combustion amount, so the natural frequency f1 of the combustion section 10 changes depending on the combustion amount. Accordingly, the natural frequency f2 of the supply section 20 changes in the same way, and 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 fuel gas is also supplied in an amount corresponding to the control amount of the proportional control valve into the fuel injection pipe 23b and the fuel distribution chamber 35,
Ejects from each spout. At this time, within the fuel distribution chamber 35, the fuel gas is directed to the fuel nozzle 3 by the fuel guide plate 33c.
3a, so even if the amount of fuel supplied changes, it is smoothly ejected. Therefore, no abnormal noise is generated.

In addition, in this embodiment, the fuel guide plate 33c is connected to the fuel injection port 3.
Although not provided for air supply path 3b, this
Each fuel jet port 33a, 33b due to the air flow passing through the
Since the pressure for each fuel injection port 33a is different,
, 33b have different fuel injection amounts and pressures,
This is because abnormal noise is likely to occur only in the fuel injection port 33a, so the best fuel guiding plate may be provided for each combustion device.

As shown in the following, in this example, even if the fuel supply amount changes, no abnormal noise is generated due to fuel injection.
Furthermore, no abnormal sound or noise is generated during ignition or steady combustion, making it possible to provide 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 the drawing]

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.

Claims (1)

[Claims] 1) A fuel distribution chamber that is provided to cover an opening of a fuel supply pipe that communicates with an air supply passage that guides combustion air to a burner, and that distributes fuel to be supplied to the burner. In a combustion device including a fuel dispersion plate having a plurality of fuel injection ports for ejecting fuel into the air supply passage, the plurality of fuel injection ports include fuel that is supplied into the fuel distribution chamber. A combustion device comprising a fuel guide member that guides fuel to the plurality of fuel injection ports.