JPH01208608A - Pressurized combustion type burner utilizing self-restored gas pressure - Google Patents

Abstract

PURPOSE:To eliminate necessity of a separate air feeding equipment, by absorbing primary combustion air using the flow energy or original fuel, restoring the energy loss in the injection of the gaseous mixture and absorbing again combustion air using the restored flow energy of the gaseous mixture. CONSTITUTION:A fuel gas is injected at a high flow velocity from an outlet 12 of a fuel nozzle 10, which a primary air is absorbed through a primary air inlet C1. The primary air is mixed with the fuel gas in a throttle section 24 to form a primary gaseous mixture which is then flowed out into a pressure restoring section 25. In the pressure restoring section 25, a velocity energy of the gaseous mixture passing through the throttle section 24 is gradually restored. A secondary air is introduced through a secondary air inlet C2 defined by a tip end of a primary mixing nozzle 20 and an opening 33 of a secondary mixing nozzle 30 to produce a secondary gaseous mixture in a throttle section 34. In an ignition section, a flow velocity of the gaseous mixture is decreased until it reaches a flame-ignitable velocity, in order to initiate combustion of the gaseous mixture.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to combustion burners. More specifically, the present invention relates to a pressurized combustion burner using self-gas pressure that is installed in a heat exchanger tube or the like that transmits heat to the outside through the heat exchanger tube.

(Prior art) For example, a gas combustion burner that is installed at the beginning of a heat transfer tube that is immersed in the frying oil of a fryer to transfer heat, and that uses city gas, household gas, or other gas, is a Venturi tube type or blow-in type. Type burners are used, and conventionally these burners eject gas directly from small holes toward atmospheric pressure.

(Problem to be solved by the invention) However, the pressure of city gas, household gas, and other gases used in these gas combustion burners is only several hundred millimeters higher in water column pressure than atmospheric pressure, and the fumarole When the water exits the hole, the pressure is reduced to a few millimeters of water, and the mixture of air and fuel gas reaches several times the required amount of air, causing the flame temperature to be lower than the theoretical flame temperature and resulting in poor combustion efficiency. There was a problem.

In addition, in the case where air is mixed in the middle and the mixed gas is ignited at the burner hole, the gas pressure loses almost all of its initial pressure energy, and combustion takes place under atmospheric pressure.
There was still a problem that the flame temperature was quite low.

In order to solve these problems, methods have been taken to supply fuel gas to the combustion chamber by separately providing an air pressure feeding device or suction device, but the problem is that the device is complicated and expensive and difficult to handle. There was a point.

The present invention was made in view of these conventional problems, and it is possible to effectively preserve the gas source pressure energy even at the combustion start point without installing an expensive air supply means, and to optimize the mixing ratio with air. The purpose of the present invention is to provide a gas combustion burner with a simple structure that enables self-control.

(Means for Solving the Problems) The gist of the present invention for solving the above object is that the outer periphery of the tip of the cylinder is formed into a conical shape, and a gas outlet is bored inside along the axis. a fuel nozzle, the inner periphery of the base end has a conical shape corresponding to the conical tip portion of the fuel nozzle, and the conical portion of the fuel nozzle is inserted and fitted with a primary air intake port having a predetermined gap. a primary air opening,
A primary mixing device in which a constriction portion of a predetermined diameter following the primary air opening and a pressure recovery portion having a shape that gradually widens toward the end are concentrically formed following the constriction portion, and the outer periphery of the tip portion is formed into a conical shape. The nozzle and the inner periphery of the base end have a conical shape corresponding to the conical tip portion of the primary mixing nozzle, and the conical portion of the primary mixing nozzle is inserted with a secondary air intake port having a predetermined gap. A secondary air opening, a constriction part of a predetermined diameter following the secondary air opening, a pressure recovery part having a shape that gradually widens toward the end following the constriction part, and an ignition part having a gradual divergence angle following the pressure recovery part. a secondary mixing nozzle formed by concentrically bored holes, a flame retention plate having a plurality of holes through which the mixed gas flows out and attached to the tip of the secondary mixing nozzle, and a flame retention plate surrounding the periphery of the flame retention plate. This is a pressurized combustion burner using self-gas pressure, consisting of a diverging tube that is installed as a gas pressure burner.

(Function) The fuel gas ejected from the injection port of the fuel nozzle at high speed is composed of the conical tip portion of the fuel nozzle into which combustion air is sucked in at the injection speed, and the primary air opening of the primary air nozzle. Air is guided from the primary air intake port and fed into the constriction part of the primary mixing nozzle, forming a primary mixed gas in the core part.

Although the throttle portion has a predetermined diameter, the amount of primary air guided is appropriately limited, and the primary mixed gas has a stoichiometric mixing ratio or less.

A part of the velocity energy of the primary mixed gas that has passed through the constriction part is gradually converted into pressure energy in the gradually expanding pressure recovery part of the primary mixing nozzle, and the pressure is recovered. , the fuel gas regains most of its original pressure. However, since the flow velocity is still higher than the flame propagation velocity, no combustion occurs.

The primary mixed gas ejected from the primary mixing nozzle now reaches high speed again, and the pressure becomes less than the jet pressure, and the secondary air is discharged from the secondary air intake configured between the secondary air opening of the secondary mixing nozzle. is introduced into the constriction section of the secondary mixing nozzle.

The diameter of the throttle part of the secondary mixing nozzle is also appropriately formed to a predetermined size, and the amount of induced secondary air is combined with the primary mixed gas and is close to the theoretically optimal air-to-fuel mixture ratio. It's worth it.

The secondary mixed gas that has passed through the throttle section of the secondary mixing nozzle as an appropriate mixed gas recovers most of the initial pressure of the fuel gas while passing through the pressure recovery section of the secondary mixing nozzle (however, (Even in the core part, the flow velocity exceeds the flame propagation speed.) It ejects to the ignition part with a large divergence angle provided at the tip, and slows down to a flow velocity sufficient for ignition and flame retention in the chain part. It is ignited at the chain part.

The flame retaining plate forms a stagnation part for the fuel fluid on the front side, and generates a vortex flow on the back part, thereby acting as a flame retainer.

The flame then transmits a flame heat flow through the divergent tube into, for example, a heat transfer tube.

(Example) An embodiment of the present invention will be described in detail below based on the drawings.

The pressurized combustion burner B using self-gas pressure consists of a plurality of parts and elements arranged coaxially in a column, and includes a fuel nozzle lO provided at the starting end and connected to a fuel source to eject fuel gas; An injector-type secondary mixing nozzle 3 into which the fuel nozzle 10 is inserted concentrically into the base and mixes fuel gas and primary air to deliver a primary mixed gas.
0, a flame retention plate 40 attached to the tip of the secondary mixing nozzle 30 to maintain a stable flame, and a flared tube 50 provided surrounding the flame retention plate 40. A burner attachment member 60 for attaching the burner to the end of a heat transfer tube or the like is provided on the outer periphery.

The fuel nozzle 10 has a mounting part 11 on its outer periphery, a conical tip, and a gas ejection port 12 bored inside along the axis.

As shown in FIGS. 2 and 3, the primary mixing nozzle 20 is provided with a mounting portion 21 at its base end to which the fuel nozzle 10 is joined, and a plurality of notches 22 for air intake. ing. Subsequently, when the fuel nozzle 10 is joined, a conical primary air opening 23 is provided to form an air passage corresponding to the conical tip of the fuel nozzle 10, and a conical primary air opening 23 is provided to form an air passage. A restricting constriction portion 24 is formed. The length ρ1 and the diameter d1 of the constriction portion 24 are important factors that limit the amount of air and determine the primary mixing ratio with the fuel gas.

Continuing from the constricted portion 24, a pressure recovery portion 25 that gradually widens toward the end is concentrically formed. The end divergence angle θ1 and the length Ll of the pressure recovery section 25 are such that the velocity energy of the primary mixed gas flowing out through the constriction part is converted into pressure energy and that the primary mixed gas is not back ignited. It is designed to maintain the flow rate.

On the other hand, the outer periphery of the tip of the primary mixing nozzle 20 is formed into a conical shape, and the cylindrical portion is provided with a mounting portion 26 for joining to the secondary mixing nozzle 30.

The secondary mixing nozzle 30, as shown in FIGS. 4 and 5,
A mounting portion 31 is provided on the inner periphery of the rear end portion to connect with the mounting portion 26 provided on the primary mixing nozzle 20, and a plurality of suction ports 32 for air suction are provided. Continued 1
A conical opening 33 for secondary air is provided corresponding to the conical end of the secondary mixing nozzle 20, and a constriction portion 34 for limiting the amount of air taken in is further provided. The constriction part 3
The inner diameter d2 and length 12 at 4 are important factors that control the amount of secondary air intake.

Furthermore, a pressure recovery section 35 is formed following the constriction section 34 and gradually widens toward the end. The pressure recovery section 3
5 acts to convert the velocity energy of the secondary mixed gas passing through the constriction part 34 into pressure energy, and the divergence angle θ2 and the length L2 are the same as that initially possessed by the mixed gas at the ejection end of the pressure recovery part 35. The structure is designed to recover most of the gas pressure that had been lost, and to prevent the flow velocity from falling below the flame propagation velocity.

Following the pressure recovery section 35, an ignition section 36 with a large divergence angle is provided, while a mounting section 37 for connecting a burner mounting member 60 is provided at the tip of the outer periphery.

As shown in FIGS. 6 and 7, the flame retaining plate 40 attached to the tip of the secondary mixing nozzle 30 has a main nozzle 41 in the center and a plurality of sub-nozzles around it. A hole 42 and a circumferential edge outlet 43 are provided by cutting out the circumferential plate portion, so that the mixed gas flows out.

As shown in FIG. 8, the flared tube 50 is provided with a mounting portion 51 on the inner periphery of the rear end, which is joined to the mounting portion 37 provided on the outer periphery of the secondary mixing nozzle, and the flame retaining plate 40 is held between the mounting portions 51. A diverging portion 53 is provided following the claw portion 52, and a mounting portion 54 that is joined to the burner mounting member 60 is provided over the entire length of the outer circumference.

As shown in FIGS. 9 and 10, the burner mounting member 60 has a mounting portion 61a in the center that is joined to the tube 50 that widens at the end.
It consists of a retaining ring 61 provided with a retaining ring 61, and a mounting plate 62 having a peripheral edge 62a formed therein for press-fitting and attaching the peripheral edge to the end of a tube such as a heat transfer tube.

Next, the effect will be explained.

The functional members constructed as described above are assembled as shown in FIG. 1 to constitute a fuel combustion burner B.

A fuel source (not shown) is connected to the base end of the fuel nozzle 10 and supplies fuel. Generally, city gas or similar gas is used as this fuel, and its supply pressure is several hundred millimeters of water column pressure higher than atmospheric pressure.

The fuel gas ejected from the ejection port 12 of the fuel nozzle 10 has a high ejection velocity at the chain part, and the low pressure becomes a velocity head, and the conical part on the outer periphery of the tip of the fuel nozzle 10 and the 1
Primary air is guided through the primary air intake port C1 formed between the primary air opening 23 of the secondary mixing nozzle 20 and the primary air opening 23 of the secondary mixing nozzle 20. The intake amount of the primary air is controlled by the diameter d of the constriction portion 24 of the primary mixing nozzle 20.

The primary air and fuel gas become a primary mixed gas while passing through the throttle section 24 and flow out to the pressure recovery section 25 .

In the pressure recovery section 25, the velocity energy in the constriction section 24 is gradually recovered, and if the angle θl is the required angle and the length Ll is the required length for the diameter dl, the velocity energy is recovered to a pressure close to that before the fuel gas is ejected. , and the end divergence angle θ and the length Ll are set so that the flow velocity at the chain portion is still not lower than the flame propagation velocity.
is planned.

The flame propagation speed in combustible gas varies depending on the type of gas, the mixing ratio with air, pressure, temperature, etc., and is not necessarily constant. The flame propagation speed in normal use is approximately several tens of centimeters per second, and the flow rate of the primary mixed gas in the pressure recovery section 25 is designed not to fall below this.

1 released into atmospheric pressure from the tip of the primary mixing nozzle 20
The pressure of the secondary mixed gas is below atmospheric pressure, and air is drawn from the secondary air intake port C2 consisting of the tip of the primary mixing nozzle 20 and the secondary air opening 33 of the secondary mixing nozzle 30. A secondary mixed gas is formed in the intake and constriction section 34, and the diameter d2 of the constriction section 34 has a control effect so that the amount of intake air mixes with the primary mixed gas to have an appropriate mixing ratio. ing.

2 mixed in the throttle section 34 and flowing into the pressure recovery section 35
In the next mixed gas, most of the initial pressure of the fuel gas is recovered in the pressure recovery section 35. However, the divergence angle θ2 and the length L2 are determined so that the flow velocity still does not fall below the flame propagation velocity.

The flow velocity of the secondary mixed gas is then reduced to a flame ignition speed at the ignition section provided at the tip of the secondary mixing nozzle 30, and combustion begins.

The flame retaining plate 40 creates a stagnation on the front side and creates a complicated vortex on the downstream side to retain the flame.

Note that the present invention is widely applicable to burners in which the combustion part gas pressure is pressurized within the pressure range by a single self-gas pressure, and by replacing the primary mixing nozzle and the secondary mixing nozzle with an insector type. It may also be in the form of an ejector.

(Effects of the Invention) As described above, the fuel combustion burner according to the present invention sucks secondary air for combustion using the energy possessed by the source gas of the fuel,
This mechanism consists of a mechanism that recovers the energy loss during injection of the air-fuel mixture and uses the energy possessed by the recovered air-fuel mixture to suck in combustion air (oxygen-enriched air or oxygen due to an oxygen-rich film) again. The mixture ratio with air can be optimally self-controlled, and since sufficient ejection pressure is maintained even at the ignition point, the flame can be sufficiently introduced into the heat transfer tube, and no other air supply means are required, making it inexpensive. It is now possible to configure

[Brief explanation of the drawing]

Each figure shows one embodiment of the present invention, and FIG. 1 is a longitudinal sectional view of a fuel combustion burner, FIG. 2 is a longitudinal sectional view of a primary mixing nozzle, and FIG. 3 is a rear section showing only one half. 4 is a longitudinal sectional view of the secondary mixing nozzle, FIG. 5 is a rear front view showing only one half, and FIG. 6 is a front view of the flame retaining plate.
7 is a longitudinal sectional view, FIG. 8 is a longitudinal sectional view of the flared tube, FIG. 9 is a longitudinal sectional view of the burner mounting member, and FIG. 10 is a rear view. B...Fuel combustion burner C supervisor...Primary air intake C2...Secondary air intake d! ... Diameter of the primary mixing nozzle constricted part 1, ... Length Ll of the primary mixing nozzle constricted part... Length θ1 of the primary mixing nozzle pressure recovery part... Primary mixing nozzle pressure recovery part End divergence angle d2...Aperture diameter of the secondary mixing nozzle constriction part 12.
...Length L2 of the secondary mixing nozzle constriction section...Length θ2 of the secondary mixing nozzle pressure recovery section...Further divergence angle IO of the secondary mixing nozzle pressure recovery section...Fuel nozzle 12...Injection Outlet 20...Primary mixing nozzle 23...Primary air opening 24...Constriction section 25...Pressure recovery section 30...Secondary mixing nozzle 33...Secondary air opening 34... ... Throttle section 35 ... Pressure recovery section 36 ... Ignition section 40 ... Flame retaining plate 50 ... Spreading pipe 60 ... Burner mounting member patent applicant Kitazawa Sangyo Co., Ltd. Kagomoto Tomizo Dai Figure 0 Figure 4 Figure 7 Figure 6 Figure 8. , Figure 9

Claims (1)

[Claims] A fuel nozzle in which the outer periphery of a cylindrical tip is formed into a conical shape and a gas jet port is bored inside along the axis, and the inner periphery of the base end has a conical shape corresponding to the conical tip portion of the fuel nozzle. , the conical portion of the fuel nozzle is in a first position with a predetermined gap.
A primary air opening into which a secondary air intake is inserted, a constriction part of a predetermined diameter following the primary air opening, and a pressure recovery part having a shape that gradually widens at the end following the constriction part are concentrically drilled. and a primary mixing nozzle whose distal end outer periphery is formed into a conical shape, and whose base end inner periphery has a conical shape corresponding to the conical distal end portion of the primary mixing nozzle. A secondary air opening in which the conical portion is inserted with a secondary air intake port having a predetermined gap, a constriction portion having a predetermined diameter that follows the secondary air opening, and a shape that gradually widens toward the end following the conical portion. The secondary mixing nozzle has a pressure recovery section and an ignition section concentrically formed with a gentle divergent angle following the pressure recovery section, and a plurality of holes through which the mixed gas flows out. A pressurized combustion burner using self-gas pressure, consisting of a flame retention plate attached to the tip of a nozzle and a diverging tube attached to surround the periphery of the flame retention plate.