JPS605235Y2 - combustion device - Google Patents

Description

[Detailed description of the invention] The present invention relates to a combustion device in which the volume of hot air and the volume of combustion air are controlled proportionally.The configuration is simple, and the combustion output can be adjusted by controlling the volume of hot air. The present invention provides a combustion device that is suitable for hot air heating devices and the like.

In liquid fuel combustion equipment that uses liquid fuel such as petroleum,
The air used for combustion must be supplied at a constant air-fuel ratio defined by the stoichiometric ratio with the fuel.

However, in the past, it was extremely difficult to stably obtain a fixed supply amount due to the influence of wind and the like.

As a result, air shortage or excess air conditions occur, resulting in poor combustion conditions and reduced thermal efficiency.

Problems caused by fluctuations in the air-fuel ratio as described in 2 also occur when the amount of fuel supplied is changed.

In other words, the combustion amount is adjusted by adjusting the atomization amount for the gun type, the injection amount for the pot type, and the vaporization area for the wick type, but in all cases, the amount of fuel supplied to the combustion section is adjusted. Therefore, if the air supply amount is constant, the air-fuel ratio may fluctuate and the above-mentioned problem may occur.

Therefore, the combustion amount adjustment range has to be a narrow range limited by the air-fuel ratio.If you try to widen the adjustment range, you have to sacrifice the optimal air-fuel ratio to some extent, and as a result, the combustion state Getting worse.

In addition, since the conventional combustion amount adjustment was done by directly adjusting the amount of fuel supplied, the adjustment device had to come into contact with the fuel, which caused corrosion due to water mixed in the fuel and deterioration of the fuel. In addition, problems such as malfunction due to adhesion of tar and the like tended to occur.

In addition, there are combustion devices that adjust the supply amounts of fuel and air in a correlated manner using mechanical damper opening/closing control means, etc. in order to maintain a constant air-fuel ratio, but this not only complicates the configuration, but also As the amount of air decreases, the allowable range of variation in the amount of fuel supplied to maintain an appropriate air-fuel ratio becomes smaller. Therefore, using mechanical opening/closing means, etc. may not be able to control the air-fuel ratio properly or may cause problems with the design of the device. There were problems such as the high degree of precision required for manufacturing.

The present invention solves the above problems, and has a structure in which fuel air is sucked into the burner by the negative pressure generated by the flow of warm air driven by a single blower, and the amount of combustion air is reduced. It is possible to provide a combustion device that uses a burner with a structure in which the amount of fuel vaporized changes according to the change in the amount of combustion, and can automatically change the amount of combustion and adjust the output by controlling the amount of hot air. It is.

Hereinafter, an embodiment in which the present invention is applied to a hot air heater will be described in detail with reference to the drawings.

In FIG. 1, a fuel tank 2 is provided at the lower part of a heater main body 1, and a burner 3 is provided above the fuel tank 2.

Above the burner 3, a propeller-type blower 4 and a motor 5 for driving the blower are provided. A baffle plate 6 having a convex shape in the direction of the blower 4 is disposed facing the blower 4.

The burner 3 is composed of a plurality of cylindrical members, and includes an inner flame tube 7, an outer flame tube 8, a combustion tube 9 located on the outer periphery of these members, and a lower end thereof connected to the fuel 10 in the fuel tank 2. Soak,
It consists of a lamp wick 11 as a fuel evaporator whose upper end is exposed between an inner flame tube 7 and an outer flame tube 8.

Furthermore, the inner flame tube 7 and the outer flame tube 8 have vaporization air ports through which vaporization air flows. a, 8a, and a premixing air lower b, 8b through which premixing air flows, and a closure disposed above the inner flame tube 7 and the outer flame tube 8 above the inner flame tube 7. A secondary air port 12 is provided between the plate 17 and the combustion tube 9 through which secondary air for combustion air flows.

Air vent for vaporization? a, 8a are located at opposite positions near the upper end of the lamp wick 11, and above them are premixing air lowers b, 8b.
are located, and the vaporizing air lowers a and 8a are located so that the secondary air and the secondary air are always in the desired ratio for combustion.
and a primary air port consisting of a premixing air lower b, 8b;
A secondary air port 12 is provided.

In addition, the inner air passage 13 of the inner flame tube 7 and the air passage 14 between the combustion tube 9 and the outer flame tube 8 are opened to the outside via a combustion air intake port 15 provided below the heater body 1. ing.

On the other hand, the pressure plate 6 is larger than the outer diameter of the combustion tube 9 and has a ventilation passage 16 between them, and the space surrounded by the pressure plate 6, the combustion tube 9, and the closing plate 17 forms a combustion chamber 18. are doing.

Further, an outer cylinder 19 is disposed on the outside of the combustion cylinder 9 and is concentric with the combustion cylinder 9 and extends upward to near the blower 4. The inner diameter is the minimum, and the inner diameter gradually increases toward the upstream and downstream sides of this part.

Furthermore, the outer cylinder 19 has the role of an air guide for the blower 4, and the ventilation path between the combustion cylinder 9 and the hot air path 20
It is opened to the outside via a hot air outlet 21 provided on the front surface of the heater main body 1.

Note that 22 indicates a hot air air supply port provided on the upper rear surface of the heater main body 1.

In addition, in the burner 3 of this configuration, combustion air (secondary air and secondary air) is sucked in by the hot air flow from the blower 4, and the amount of vaporized fuel 10 from the lamp wick 11 is the same as that for vaporization. Air vent? It is configured to be approximately proportional to the flow rate of vaporizing air passing through a and 8a.

That is, in the burner 3 of this configuration, the combustion amount is approximately proportional to the combustion air flow rate.

In FIG. 1, solid line arrows indicate the flow of warm air, and dashed-dotted line arrows indicate the flow of combustion air and combustion exhaust gas.

The operation when the burner 3 of the heater configured as described above is combusted will be explained below.The blower 4 is rotated by the drive of the motor 5, and the warm air is sent to the hot air outlet 21 via the hot air intake port 22. Air (solid arrow) flows.

When this hot air passes between the outer periphery of the baffle plate 6 and the outer cylinder 19, the inside of the combustion chamber 18 is brought into a negative pressure region via the ventilation path 16 due to air turbulence on the outer circumference of the baffle plate 6.

Therefore, from the combustion air supply port 15 to the ventilation passages 13 and 1.
Combustion air is drawn into the combustion chamber 18 through 4, and since the magnitude of the negative pressure is proportional to the hot air air flow rate, the combustion air flow rate is also proportional to the hot air air flow rate. Become.

On the other hand, the vaporization amount of the fuel 10 from the lamp wick 11 is proportional to the primary air flow rate, and the vaporization air lower a,
8a, premixing air lower b, 8b and secondary air port 12
Therefore, the amount of vaporized fuel 10 from the lamp wick 11 is approximately proportional to the hot air flow rate.

Therefore, the combustion amount of the burner 3 in the combustion chamber 18 is
It can be adjusted by adjusting the amount of air blown.

On the other hand, in order to more effectively obtain the negative pressure in the combustion chamber 18 due to the hot air flow, there is a method other than increasing the hot air flow rate described above. It is also possible to flow the water at right angles to the water.

However, when a propeller type blower is used as the blower 4, the air flow from the blower 4 has the property of rotating in the direction of rotation of the blower 4 and spreading outward due to centrifugal force. The flow at the outer peripheral edge of the plate 6 is not necessarily at right angles.

Therefore, in this embodiment, as shown in FIG. 1, the inner surface of the outer cylinder 19 is shaped such that the diameter of the portion facing the baffle plate 6 is the minimum, and the inner diameter gradually increases toward the upstream side.
Of the air flow blown by the blower 4, the flow that collides with the inner surface of the outer cylinder 19 becomes a flow toward the central axis direction of the outer cylinder 19 after colliding with the inner surface of the outer cylinder 19.

On the other hand, the flow that directly reaches the outer peripheral end of the baffle plate 6 is
However, the air flow at the outer peripheral edge of the baffle plate 6 is a flow that merges with the former air flow, and the air flow at the outer circumferential edge of the baffle plate 6 is The flow is approximately perpendicular to

Therefore, the negative pressure in the combustion chamber 18 due to the hot air flow flowing to the outer peripheral end of the baffle plate 6 can be more effectively obtained.

FIG. 2 is a diagram illustrating this state.

That is, out of the air flow from the blower 4, if the flow that flows in the direction of the center axis of the outer cylinder after colliding with the inner surface of the outer cylinder 19 is ``al'', and the flow that flows directly toward the outer peripheral edge of the air baffle plate 6 is b, then 6 The air flow at the outer peripheral edge is C, which is the vector sum of a and b.
This is the result.

Further, by forming the inner surface of the outer cylinder 19 into a shape in which the diameter on the downstream side of the portion facing the air baffle plate 6 is gradually expanded, the passage area of the hot air path 20 can be increased, and the hot air path 20
It has the feature of being able to reduce pressure loss inside.

FIG. 3 shows another embodiment of the present invention, in which the inner diameter of the outer cylinder 19' is gradually enlarged in the upstream direction only on the upstream side of the baffle plate 6.

Furthermore, the outer periphery of the combustion tube is used as a hot air path, and the exhaust gas and the airflow from the propeller fan are mixed and passed through.

That is, since the high-temperature airflow is passed through, it has the effect of keeping the combustion cylinder warm.

Therefore, since there is no need to cool the flame inside the combustion tube, deterioration of combustion characteristics can be prevented.

In addition, in Figures 2 and 3, the same numbers as in Figure 1 are
Shows the same parts.

As explained above, the combustion device of the present invention has a burner whose combustion amount is approximately proportional to the combustion air flow rate, and a negative pressure inside the combustion chamber that changes in proportion to the hot air air flow rate from the blower. It is composed of a wind baffle plate, which creates a negative pressure inside the combustion chamber to draw in combustion air, and also allows the air to flow more effectively at the outer peripheral edge of the baffle plate, making it possible to create a combustion chamber with a negative pressure inside the combustion chamber. On the other hand, it has a simple structure and can maintain extremely stable combustion.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a combustion device according to an embodiment of the present invention;
FIG. 2 is a vector diagram for explaining the direction of air flow at the outer peripheral end of the baffle plate, and FIG. 3 is a sectional view of a combustion device according to another embodiment of the present invention. 3...Burner, 4...Blower, 6...
...Blast plate, 9... Combustion tube, 15...
...Combustion air supply port, 16...Vent passage, 18
... Combustion chamber, 19,19' ... Outer cylinder,
20...Hot air path, 21...Hot air outlet, 22...Hot air air supply port.

Claims (1)

[Scope of utility model registration request] A propeller fan is disposed above the burner and facing the burner, an outer cylinder is disposed outside of the burner and the propeller fan, and a center is disposed between the burner and the propeller fan in the direction of the propeller fan. A generally conical baffle plate is provided that protrudes from the outer cylinder, and a hot air path is provided between the combustion tube of the burner and the outer cylinder, and the outer cylinder has an inner diameter of a portion facing the outer peripheral edge of the baffle plate. A combustion device that has a smaller diameter than the other parts and gradually expands at least on the upstream side.