JPH0130048B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a burner that emits a transparent blue flame and enables complete combustion of liquid fuel (gas oil). This burner is particularly suitable for use with regenerators such as boilers.

Prior Art and Problems to be Solved by the Invention In ordinary blue flame burners, when starting cold, the fuel does not atomize sufficiently, making starting difficult and
In some cases, it may become impossible to start.

In order to solve these problems, British Patent No. 948075 discloses a burner in which the fuel supply pipe and the combustion air supply pipe are nested, and
No. 51-48041, Utility Model Publication No. 13038, 1983, and Japanese Patent Application Publication No. 1983-
No. 139131 describes a configuration in which fuel oil and combustion air are premixed or fuel oil and combustion air are preheated.

However, in a burner having such a configuration, it is necessary to effectively utilize premixing air and combustion air to achieve complete combustion.

An object of the present invention is to provide an overall structure of a burner equipped with a multi-stage blower that can effectively supply air for complete combustion of fuel.

Means for Solving the Problems According to the present invention, there is provided a liquid fuel burner that generates a transparent blue flame and performs complete combustion of fuel, which includes a combustion chamber having a throttle hole for blowing out the blue flame. , a conduit for supplying liquid fuel under pressure to the combustion chamber, a fuel atomizer installed at the forward end of the conduit, and a fuel atomizer formed in front of and around the atomizer and communicating with the combustion chamber via a throttle passage. A premixing chamber, a conduit supplying pressurized primary air to the premixing chamber, a conduit supplying pressurized secondary air to the combustion chamber, and a device for igniting the flame and controlling the burner. The burner includes a multi-stage blower for supplying pressurized primary air and pressurized secondary air, the blower being formed by two side members and a bulkhead/spacer element, the blower being formed by the bulkhead and the bulkhead spacer element. - two internal cavities communicated with each other via passages in the spacer, a first impeller or fan rotatably mounted in one cavity, and a second impeller or fan rotatably mounted in the other cavity; a second impeller or fan, an air inlet passage communicating with one of the cavities, an air supply passage extending from the other cavity to passages for primary and secondary air of the burner, and this air inlet supply passage; A control valve arrangement is provided.

According to the present invention, primary and secondary air from a single blower can be effectively controlled to enable complete combustion of fuel.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Further features and advantages of the invention will become apparent from the following detailed description of preferred embodiments, taken in conjunction with the accompanying drawings.

Referring to the drawings, the burner assembly according to the present invention includes a burner 1, a blower 2, and a fuel (gas oil).
It includes a pump 3, a box 4 for the electrical control circuit and a box 5 for the timer.

Blower 2 and pump 3 are driven by a common electric motor 6. Blower 2 is a two-stage type, and the sucked air is divided into two successive stages,
That is, it is compressed along two continuous flow paths.
For this purpose, a blower (Fig. 1, 2, 6)
is a rotating assembly comprising three fixed structural elements, namely two box-shaped side members 7, 8 and an intermediate spacer bulkhead 9, and two fans, namely impellers 10, 11, arranged on either side of said bulkhead 9. It consists of The three fixing elements are bolts or screws 1 inserted into projections 13 suitably provided in the circumferential direction.
2 are mutually held together. Juan 10, 11
are fastened together by screws 14 and shaft 16
It is locked by a key 15 (FIG. 6). This shaft 16 is rotatably supported by ball bearings 17 mounted on the side members 7 and 8. axis 16
is directly connected to the output shaft 18 of the electric motor 6.

The fixed or stationary elements 7, 8, 9 constitute a box 19 below the fans 10, 11, which box has a rear opening or intake port 20 with a throttle valve 21 acting as an intake valve;
It has two front ports 22, 23 for the supply of pressurized air. (Figure 2) Valve 21
(Fig. 7) is also a metering valve, for example, hole 21
a fixed disk 21a having a diameter b, and a hole 2 that can be controlled by a screw 21e to align with the hole 21b.
1d and a rotating disk 21c.

A first flow path 24 is formed in the box 19, one end of which communicates with the intake port 20 through a block 25 of sound absorbing material for damping vibration and noise, and the other end of which connects to the intake port 20 through a block 25 of sound absorbing material for damping vibrations and noise. It communicates with an extending centrifugal conduit 26 .

The outlet of the conduit 26 communicates with a second conduit 27 provided through the partition wall 9. This second conduit carries air from the conduit 26 provided on one side of the partition wall 9 to the fan 11.
and is adapted to feed a centrifugal conduit 28 extending circumferentially and on the opposite side of the partition wall 9.

The conduit 28, like the flow path 24, partially extends within the sound absorbing material 25 and communicates with a third flow path 29 that is directly connected to the ports 22, 23.

To get the blue frame, blower 2
It must be supplied with air at a pressure of 500 to 800 mm water column, preferably 650 to 800 mm water column.

The electric motor 6 drives a pump 3 which supplies the burner 1 with liquid fuel under pressure (i.e. gas oils of various grades with the exception of heavy furnace oil).

In order to increase the efficiency of the burner 1, it is preferable to preheat the gas oil. For this purpose, the pump 3 has a discharge 30 connected to one end of a coil 31 (preferably made of copper) and the other end of the coil connected to an insulated conduit 32 leading to the burner 1. The coil 31 is in a state of heat exchange with the electric motor 6. As is known, electric motors generate considerable heat during operation, which must be removed and is usually released into the environment. By providing the coil 31, the heat generated in the electric motor 6 is transferred to the gas oil flowing inside the coil. The gas oil is preheated and acts as a cooling fluid for the electric motor 6.

Burner 1 is attached to blower 2 by bolts 33. These bolts 33 are passed through holes in the flange 35 of the hollow body 36 constituting the main body of the burner 1, and then inserted into the screw holes 34 of the blower. Inside the hollow body 36 and at the blower opening 22, a funnel-shaped union 37 is provided, which directs the air flowing through the opening 22 to the hollow body 36 with respect to the longitudinal axis of the burner 1. It is adapted to direct into a coaxially extending primary air conduit 38.

A flow control valve 39 (second
), the valve is driven by an electromagnetic device generally designated 40, which in turn is controlled by a timer 5. The valve 39 includes a T-shaped part 41 forming a valve seat 42, in which a valve element 43 is mounted displaceably at right angles to the direction of flow (see up and down arrows). This valve element 43
for example consists of a disc having a diameter that interrupts the span of the valve seat 42. Preferably, in a position where the entire flow is blocked (valve closed position),
The valve element 43 is adapted to allow the supply of a minimum amount of primary air without completely blocking the air flow path. The minimum amount position of the valve element 43 on the valve seat 42 can be adjusted, for example, by a screw (not shown) that passes through the valve seat 42 from the outside and abuts the valve element 43.

The outlet end of the conduit 38 is provided with an external thread 44 (FIG. 3) into which a nozzle 45 having the same internal diameter as the conduit 38 is threaded. Nozzle 4
5 includes a metering or throttle passage 46 with an adjacent frustoconical portion 47.

Coaxially within the conduit 38 is a conduit 48 which serves as a gas oil supply line. This conduit 48 is connected to two set screws or cap screws 4.
9, these screws are screwed into the conduit 38, with their tips protruding into the conduit 38 and engaging with the outer wall surface of the conduit 48 (FIG. 5). An annular space 50 is thus formed between the inner conduit 48 and the outer conduit 38 into which the primary air from the opening 22 of the blower 2 flows through the manifold 37 and the valve 39. The primary air directed into the annular space 50 is e.g.
Electrical resistor 51 arranged to cover the inner surface of 7
Preheat as shown in Figure 2.

The end of the conduit 48 near the valve 39 is closed by a threaded head 52 which is tapered on its outer surface and which, together with the inner wall of the conduit, is closed for a cartridge 53 containing an electrical resistor. It constitutes a chamber or a receiving seat. The resistor cartridge 53 has an outer dimension smaller than the inner diameter of the conduit 48, so that an annular space 54 is formed between the inner wall surface of the conduit 48 and the cartridge, and the gas oil from the pump 3 flows into the coil 31. , conduit 32 and inlet conduit 55 . This inlet conduit 55
One end communicates with the conduit 32 and the other end communicates with the annular space 54. For this purpose, the conduit 55 is secured to the conduit 48, for example by screwing into the embossment 56 of the conduit 48 (FIG. 3). The gas oil flowing from the conduit 55 flows into the cartridge 5.
3 and flows along the space 54.

Inside the conduit 48 there is a partition 57 defining a gas oil passage 58, the gas oil flowing from the space 54 through a valve seat 59 of this recess 57. A valve element 60 abuts this valve seat. For example, the spherical valve element is loaded by a spring means, such as a coil spring 61. The opposite end of the spring abuts a hollow screw 62 threaded into conduit 48. Also threaded into conduit 48 is a filter 63 and a sprayer (indicated generally at 64). Conduit 48 projects from conduit 38 so that a sprayer 64 is positioned within nozzle 45 . Nozzle 4
5 is supported within an electrode holder body 65 housed coaxially with a sleeve 66 supported by a support ring or flange 67 . The electrode holder body 65 is locked in place by a stud or cap screw 68 threaded into the sleeve 66. Sleeve 66 is attached to ring 67 by bolts 69. Bolt 70 is ring 67
is fixed to the end flange 71 of the hollow body 36.
Thus, conduit 48 is supported on one side by screw 49 and on the other side by conduit 55,
On the other hand, the conduit 38 has one end supported by the electrode holder body 65 through the nozzle 45, and the other end supported by the union 37 through the component 41.
The conduit 36 is coaxial with the sleeve 66 and the conduits 38, 48 and has a conical inner portion 72 at the flange 71, which converges towards the burner axis X--X.

At the opposite end of the conduit 36 a hole 73 is formed which communicates with the port 23 of the blower 2 for admitting secondary air. As can be seen in FIG. 2, the hole 73 consists of a longitudinal section and a radial section and is elbow-shaped. The radial section extends outwardly of the conduit 36 to a block 74 (fixed to the conduit 36 by bolts 75), in which the blocking hole 73 and the restricting screw 76 are threaded. Preferably, screw 76 has a knurled head 77.
and is locked in place by a knurled internally threaded ring 78. The secondary air flows from the port 23 to the hole 73 and from there to the inner wall surface of the conduit 36 and the conduit 3
It flows into the space 79 formed by the outer surface of 8. The air expands in this space and is then constricted at the cone 72 of the conduit 36 and the ring 67, increasing its velocity. The secondary air then flows into an annular chamber 80 formed by the conical diffusion wall 81 of the sleeve 66 , the electrode holder body 65 , a portion of the conduit 38 and the nozzle 45 . Before entering this annular chamber 80, the secondary air flows around the conduit 38, preferably at the conical portion 7 of the conduit 36.
Heating is provided by a sleeve-type electrical resistor 82 located extending at 2 . This resistor 82 and cartridge 53 are connected to the lead wire 83,
84 to the power supply. These leads 83, 84 are drawn into the conduit 38 through a gas-tight passage generally indicated at 85.

The secondary air further expands within the annular chamber 80, and then expands through the holes 87, 88, and
It enters the combustion chamber 86 through 89 (FIG. 4). The combustion chamber 86 is bounded on one side by the electrode holder body 65 and on the other side by a large nozzle 90. This large nozzle 90 has an axial throttle hole 92 with a conical inner wall surface 91 . The large nozzle 90 abuts a circumferential shoulder 93 of the sleeve 66 and is secured by a set screw 94.

Electrode holder body 65 is fitted into a cylindrical inner surface 95 adjacent frusto-conical portion 81 of sleeve 66 . This electrode holder body 65 has a central hole 96 formed therein, into which the nozzle 45 is inserted.
The electrode holder body 65 has an annular shape (FIG. 2), with one side defining a frusto-conical cavity 97 within the combustion chamber 86 and a V-shaped groove 98 formed on the opposite side. This groove is formed by the frusto-conical wall surface 81 of the sleeve 66.
Together, they form an annular cavity 80. The three holes 87, 88, 89 of the electrode holder body 65 are aligned with the axis -
It extends obliquely to the Holes 87 and 88 each loosely accommodate an ignition electrode 99, and hole 8
9 is adapted to receive a thermal detection device (not shown).

As can be seen in FIG. 3, a primary air/fuel premixing chamber 100 is defined between the frusto-conical inner wall surface 47 of the nozzle 45 and the atomizer 64, and this chamber is used for combustion through the throttle passage 46 of the nozzle 45. It communicates with room 86.

The burner assembly according to the invention operates as follows.

Pump 3 is connected to a fuel source (e.g., a "standard" gas oil, i.e., a commonly available grade of gas oil, or a gas oil with a higher density than standard, close to naphtha), and circuit 4 is connected to the power source. After connecting to the burner, program the burner to a "pre-sweep" cycle with pressurized air as required by current regulations. This pre-sweep cycle is absolutely necessary in ordinary boilers to remove any traces of gas or residual mixture pockets, and is provided in the burner of the present invention because it is constantly operated under pressure. However, it should be
82) may be used to give time to reach a stable state. The pre-sweep cycle may take about 10 seconds and blows air from the blower 2 through the holes 73, when the valve element 43 is in the idle position, ie, almost fully closed. Electrode 99 will then ignite the fuel. After a predetermined period of time, for example 20 seconds, valve 1
01 is activated to allow fuel to flow in. This valve 101
is provided in the inlet conduit 32 (FIG. 1). The fuel delivered to the inner space 54 through the conduit 32 and thus through the conduit 55 under pressure (for example 15 atmospheres) is preheated by the resistor 53 during a cold start and will not mist even if the fuel is quite dense. and improve the mixing condition. Next, the fuel is passed through passage 5.
8 to open the valve 60, screw 62, and film 6.
3 and exits the atomizer 64 through the restrictor passage 46
It enters a premixing chamber 100 that converges toward . This premixing chamber 100 is connected to the combustion chamber 86 through the throttle passage 46.
It also communicates directly with an annular space 50 containing primary air around its entire circumference. Here, the primary air is also preheated by the sleeve resistor 82 during a cold start. Thus, the sprayer 64
The atomized fuel from is mixed with primary air in the premix chamber 100. However, contact of the atomized gas oil with the inner wall surface 47 of the nozzle 45 must be prevented. Pressurized primary air flows along this inner wall surface, capturing the atomized gas oil from the tip of the atomizer 64 and homogeneously mixing it.

Otherwise, droplets of gas oil would adhere to the inner wall surface 47 of the nozzle 45 and return to a liquid gas oil state, particularly during cold starts, and would seep along the nozzle 45 and conduit 38.

The atomized gas oil is wrapped in primary air and passed through the nozzle 45.
This provides sufficient time for optimal mixing and convergence along the longitudinal axis of the combustion chamber 86.

After passing through the throttle passage 46, the air-fuel mixture is ignited by the electrode 99 and the combustion chamber 8 is ignited by the electrode 99.
6 as a transparent blue flame, and secondary air simultaneously flows into this combustion chamber through the holes 87, 88, 89 of the electrode holder body 65.

This secondary air, at least during cold start,
Preheating is provided by sleeve resistor 82.

After a short period of time, for example a quarter of a second, the solenoid valve 40 moves the valve element 43 to the fully open position to increase the flow of primary air, which causes the transparent or white flame within the combustion chamber 86 to turn blue. Convert to frame. After a short time, Mymer 5
cuts electrode 99, then resistors 53, 37, 82
Also cut.

The secondary air can be regulated by screws 76 and enters a relatively large receiving space consisting of an interior space 79 . However, before entering chamber 80, it is passed through a neck formed by the sloped wall 72 of conduit 36 and the inner surface of ring 67, increasing its velocity.
In this way, a strong turbulent flow is created in the annular chamber 80 from which the secondary air flows through the holes 87 and 8 of the electrode holder body 65.
8 and 89 and reaches the combustion chamber 86.

The secondary air is heated in the vicinity of the resistor 82 provided in the annular chamber 80 along the holes 87, 88, 89 and adjacent to the inclined wall 72, while this also serves to cool the electrodes.

The heat detection device attached to the hole 89 of the electrode holder body 65 has the function of stopping the burner when the blue flame does not occur or disappears after the electrode 99 is de-energized.

Achieving blue flame conditions depends on maintaining nearly normal combustion conditions through precise burner adjustment.

More specifically, the blower 2 is effective in supplying both primary and secondary air in sufficient quantities (at appropriate pressures). For example, the throttle hole 92 of the combustion chamber 86
To obtain a pressure of approximately 300 mm of water column, blower 2 must be
For a 16000KCal (64000BTU) burner, 18−
It must be capable of generating a flow rate of 20 m ³ /min and a final supply pressure of about 500 mm water column in the flow path 29. In view of pressurizing the inside of the regenerator of the boiler, furnace, etc. in which this burner is installed, it is advantageous if the flame exits the combustion chamber 86 under pressure.

If the pressure within the combustion chamber 86 is too low, the flame will not be able to flow out of the throttle hole 92 and will disappear. Conversely, if this pressure is too high, the frame will not disappear, but instead of a transparent blue frame, a bluish-white or opaque frame will result. The primary air flow path is the throttle passage 46 of the nozzle 45.
The secondary air can be adjusted by manipulating the screw 76. In any event, the pressure within combustion chamber 86 must be sufficient to support combustion. Due to the shape of the combustion chamber 86 that becomes narrower toward the throttle hole 92,
When the internal pressure is zero, turning off the ignition electrode 99 will extinguish the flame. If the pressure is too high, the flame will eject from the combustion chamber 86, leave the burner, and go out. By increasing the air pressure within combustion chamber 86 within limits, a whiter flame is obtained because combustion occurs in excess air. At the exit from the aperture 92, the frame changes from a pale, almost transparent blue (the optimal color) to a darker, opaque blue. Due to the presence of a white frame at the exit from the combustion chamber, it is necessary, for example, to use a nozzle 45 with a smaller diameter throttle passage 46, or to use a premixing chamber 100 of larger dimensions, or a combination thereof. By combining or reducing the length of the mixing zone, a higher pressure must be applied to the primary air/fuel jet.

If the frame becomes too blue (dark blue), operate screw 76 to control the amount of secondary air flowing in.

The color of the flame is also influenced by the length and diameter of the combustion chamber 86 and the size of the throttle hole 92. If the combustion chamber is too narrow, it won't expand enough and the flame will make loud noises or go out. Conversely, if the frame is too wide, the white frame becomes predominant. If the combustion chamber 86 is too short, the flame will disappear. If the blue flame encounters an obstruction or has insufficient pressure, it will turn pink to blue and emit carbon monoxide, resulting in soot. Conversely, if the combustion chamber 86 is too long, no serious problems will be encountered;
2, the velocity of the mixture, and the total volume of the combustion chamber. If the combustion chamber 86 is too long, the flame may break into pieces and fly off.

The diameter of the throttle hole 92 depends directly on the volume required for complete combustion within the combustion chamber, but in any case sufficient pressure is maintained within the combustion chamber to maintain the flame in a homogeneous jet 102 (FIG. 1). The shape should be concentrated in an approximately cylindrical axial area (which can reach 25-30 cm in length).

The optimal blue (transparent blue) frame is combustion chamber 8
Although it is already blue before exiting the aperture hole 92 of No. 6,
Inside the combustion chamber, white flame predominates. In order to obtain an optimal blue flame, it is important to control the dimensional relationship between the throttle passage 46 of the nozzle 45 and the throttle hole 92 of the combustion chamber. The selection and adjustment of this dimensional relationship is, for example, as follows.

For example, assume that the diameter of the throttle passage 46 is chosen to be 14 mm and that when adjusting the burner 1 the flame from the throttle hole 92 changes from dark blue to red. next,
By rotating the nozzle 45 and moving it back and forth, the distance between the throttle passage 46 and the throttle hole 92 can be adjusted. If the frame does not become a transparent blue frame, the cap 8 may be replaced with a nozzle 45 of a different diameter, or the outlet 90 may be replaced to change the diameter of the aperture hole 92. Furthermore, depending on whether the burner is used in a regenerator, boiler, furnace, etc. operating under pressure with a blue flame or as a needle with an open flame, the blower 2 The volume and pressure of air sent by can be adjusted.

Many changes and modifications may be made to the invention as described herein without departing from its scope.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a burner assembly according to the invention;
Fig. 2 is an enlarged longitudinal sectional view of the burner and blower of Fig. 1 taken along the vertical plane in the axial direction, and Fig. 3 is a longitudinal sectional view showing the details of Fig. 2. , FIG. 4 is a perspective view of the electrode holder element constituting the combustion chamber of the burner, and FIG. 5 is a perspective view of the electrode holder element constituting the combustion chamber of the burner.
An enlarged cross-sectional view along the line, Fig. 6 is the − of Fig. 2.
7 is a front view of the inlet air valve. 1... Burner, 2... Blower, 3... Pump, 6... Electric motor, 10, 11... Fan, 45
……nozzle.

Claims (1)

[Claims] 1. A liquid fuel burner that generates a transparent blue flame and performs complete combustion of fuel, which includes a throttle hole 92 for blowing out the blue flame.
A combustion chamber 86 having a combustion chamber 86, a conduit 54 for supplying liquid fuel under pressure to the combustion chamber 86, a fuel atomizer 64 installed at the front end of this conduit 54, and a fuel atomizer 64 formed in front of and around this atomizer 64. A premixing chamber 100 communicating with the combustion chamber 86 via the throttle passage 46, a conduit 50 supplying pressurized primary air to the premixing chamber 100, and a conduit 79 supplying pressurized secondary air to the combustion chamber 86. and a device 99 for igniting the flame and controlling the burner, the burner comprising a multi-stage blower 2 for supplying pressurized primary air and pressurized secondary air, the blower comprising: two internal cavities 26, 28 formed by the two side parts 7, 8 and a septum/spacer element 9 and communicated with each other via a passage 27 of said septum/spacer; empty space 2 on one side
a first impeller or fan 10 rotatably mounted on the other cavity 28, a second impeller or fan 11 mounted on the other cavity 28, and an air inlet passage 24 communicating with the one cavity 26; an air supply channel 29 extending from the other cavity 28 to channels 50, 79 for primary and secondary air of the burner;
Control valve device 2 provided in this air inlet supply passage
1. A burner comprising: 1. 2 comprises an electric motor 6 for driving the blower 2 and a passage section 31 for supplying fuel, the passage section including a conduit arranged to exchange heat with the electric motor 6, so that the fuel flows into the electric motor 6; 6. The burner according to claim 1, wherein the burner acts as a coolant for the combustion chamber 86 and is preheated before reaching the combustion chamber 86. 3. Claim 2, in which the conduit 31 includes a metal coil section disposed around an electric motor.
The burner described in section. 4. The burner according to any one of claims 1 to 3, wherein a sound absorbing material 25 is arranged around the air inlet passage 24 and the air supply passage 29 to reduce noise.