KR900002317B1 - Operation method and apparatus of burner burning in pulse type - Google Patents

Abstract

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Description

Operation method and apparatus of burner burning in pulse type

1 is a longitudinal sectional view of a heat exchanger incorporating a burner that burns in a pulsed form.

2 is a cross-sectional view taken along the line II-II of FIG.

3 is a schematic diagram of an electrical control system of a thermal regeneration system in which two heat exchangers of the type shown in FIG.

* Explanation of symbols for main parts of the drawings

1: heat exchanger 2: burner

3: butterfly valve 4: heat storage and discharge device

5 air injector 8 combustion chamber

26: ignition electrode 31: see-through tube

32: UV flame detector 41: fuel gas supply

44: mixing chamber 47,69: air supply

50: main fuel gas open and close solenoid valve

51,54,55,91: regulating valve

52: pilot flue gas on-off solenoid valve

53 gas pressure regulator 58 stub pipe

79,80 Wing 81,82 Semi-circular seal

85,86: Nozzle 89: Main air open and close solenoid valve

100: heat storage bed 109: metal grid

110: full high pressure chamber

The present invention relates to a method and apparatus for operating a burner that is burned in a pulse form.

The burner which is burned in a pulse type means a burner in which a burned step and a non-burned step, that is, a combustion step and a non-burning step are performed periodically, and the burning step and the non-burning step are formed in a series of pulse types.

Burners of this kind are used to heat such enclosures, such as furnaces and the like, and are capable of being mounted on the walls of the furnace.

Pulsed burners have a combustion chamber which is used to burn fuel (main fuel) with forcibly introduced combustion air (main air), which is preheated when the burner forms part of the heat exchanger. There is an inlet for the main air and an outlet for the combustion of fuel from the combustion chamber in the furnace to be heated.

A fuel injector is used to inject the main fuel during combustion, for example natural gas and to continue to inject the main fuel into the combustion chamber during the combustion phase, while a pilot burner is used to ignite the injected fuel.

The fuel injector consists of a pipe adapted to receive the main fuel from a suitable source of fuel, which is always injected into the combustion chamber through the walls of the combustion chamber. The pilot burner has a tube adapted to receive a mixture of air supplied at a pilot level ratio and fuel at a pilot level ratio.

Ignition of the pilot fuel / pilot air mixture (pilot flame mixture) with an ignition device such as a spark igniter generates a pilot flame at the end of the tube of the pilot burner to ignite the fuel injected by the fuel injector. In this case, the pilot flame is placed at the point where the injected main fuel can be ignited.

After ignition, the main fuel injected by the fuel injector at the main rate is combusted with the main combustion air in the combustion chamber of the burner and as a result, a flame (main flame) is generated and ideally filled in the combustion chamber.

The duration of the combustion phase, during which the main fuel is continuously injected by the fuel injector, turns on the fuel injector at the beginning of the combustion phase to supply fuel and turns off the injector at the end of the combustion phase. It is set by the combustion period timer that turns off the fuel supply.

Alternatively, the duration of the combustion step may be such that the fuel injector is turned ON when the temperature of the furnace is below a predetermined level to supply fuel, and the fuel injector is turned OFF when the temperature is above the predetermined level. It can also be set as a thermostat to block the supply. For stability, a device is installed to check whether there is a main flame in the combustion chamber or a pilot flame at the end of the pilot burner.

The device is mostly a detector that responds to the frequency of light emitted by the flame, eg ultraviolet light. However, a thermocouple lamp can also be used as a flame detector.

When there is a flame, the detector generates a detection signal to keep the burner running. In this case, UV detectors are used as detectors, and any flames produced by the pilot burner or the main flames produced by burning in the combustion chamber can be viewed from the outside of the burner with the eyes or with a properly placed flame detector. Perspective ports were installed on the walls of the chamber.

If a flame is not detected during the combustion or noncombustion phase, the detection signal from the flame detector is interrupted and the burner is automatically stopped. In this case, when the burner is in the combustion phase, the fuel supplied from the fuel injector is automatically shut off and no flame is generated in the combustion chamber.

In most conventional systems, the fuel supplied to the pilot burners is automatically shut off to prevent pilot flames from occurring. One problem with this type of safety device is that the detector is only satisfactory in the presence of a pilot flame and the burner burns only during the combustion phase. This is followed by a risk if the main fuel air for burning the main fuel in the combustion chamber does not reach the combustion chamber for some reason.

This can happen, for example, when the heat storage bed of the heat exchanger is blocked. In this case, if the main fuel is continuously injected into the combustion chamber of the burner at the main rate, purely fuel is supplied only to the furnace and some other burners, and there is a risk of explosion when suddenly ignited. For this reason, pulsed burners are always operated to extinguish the pilot flame (after the main fuel supplied by the fuel injector is ignited) during the combustion cycle. This can easily be done by blocking the supply of pilot fuel.

At the end of the combustion phase the supply of pilot combustion is restarted and ignited again. Under normal conditions, if the main combustion air does not reach the burner's combustion chamber during the combustion cycle, the shutoff is automatically performed and the pilot tube is continuously supplied with the pilot tube during the combustion cycle because only the fuel supply is cut off. .

Even if the amount of pilot air supplied in this way is small, the amount of this air supply stimulates the combustion of the fuel in the impacted area when it collides with the main fuel released by the fuel injector, so that the flame is present. Is enough to produce a stable small flame that is sufficiently detectable.

In practice, the pilot fuel supply is done just before the commencement of the combustion phase, and reignition of the pilot fuel is of course necessary at this point and the supply of pilot fuel is cut off immediately after commencement of the combustion phase. In addition to shutting off the pilot burner periodically, control must be made to ensure that the operation of the pilot burner is properly coordinated with the operation of the fuel injector.

The use of such controls is inconvenient to use and, in particular, when the duration of the combustion and non-combustion stages is short, there is an overload which leads to a defect in the balance between the operation of the pilot burner and the operation of the fuel injector. The above defects may cause a large loss.

It is an object of the present invention to ensure that pulsed burners are operated safely, without the need to continuously shut down the operation of the pilot burner and to coordinate the operation of the fuel injector and the pilot burner.

According to one aspect of the invention there is provided a method of operating a burner that is pulsed. The method adjusts the fuel supply ratio between the pilot level and the main level to generate the flame, supplies air at the pilot ratio to premix with the fuel before ignition, premixes the fuel and air and detects the flame. If not, the supply of fuel is terminated.

Each level above is adjusted between the pilot level during the non-combustion phase and the main flame level during the combustion phase and means that the pilot air level is high enough to assist combustion of the fuel at the pilot rate.

According to another aspect of the invention there is also provided an apparatus for operating a burner that is burned in a pulsed fashion. The above apparatus is a device for adjusting the fuel supply ratio between the pilot level and the main level to generate a flame, a device for supplying air at a pilot ratio to premix with fuel before ignition, a device for premixing fuel and air And it is composed of a device that terminates the supply of fuel when the flame is not detected.

Each of the above levels is adjusted between the pilot level during the non-combustion stage and the main flame level during the combustion stage and means that the pilot air level is sufficient to assist combustion of the fuel at the pilot rate. In essence, the present invention provides a pilot burner that operates alternately to a pilot burner and a fuel injector during the non-combustion and combustion phases, respectively.

In another aspect, the present invention provides a fuel injector that operates alternately to a fuel injector and a pilot burner, respectively, during the combustion and non-combustion phases. In some cases it is necessary for the apparatus to provide pilot flames and main flames. In this case, as the fuel feed rate is adjusted between the pilot ratio and the main ratio, the flame is adjusted between the pilot flame and the main flame during the non-combustion and combustion phases, respectively.

Therefore, it is not necessary to turn off the pilot flame during the non-combustion phase and there is no need to control to coordinate the burner operation with the pilot burner operation. When pilot air is always present in the fuel, it is always premixed with the fuel. In this case, there is a sufficient amount of air at the outlet of the fuel injector to generate a pilot flame, but the amount of air is insufficient to maintain combustion of the fuel injected at the main rate.

Therefore, if the main combustion air fails to reach the combustion chamber for some reason during the burner's combustion cycle, the fuel will not burn and there will be no flame to be detected by the flame detector. At this time, the burner is automatically shut off as a conventional burner which is burned in a pulse type is operated.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

In Fig. 1, at one end of the heat exchanger 1 there is a burner 2, which is burned in pulses, at the other end there is a butterfly valve 3 which closes the other end of the heat exchanger 1, Between both ends, a heat storage and discharge device 4 through which gas can penetrate is disposed, and an air injection device 5 for injecting main combustion air into the heat exchanger 1 includes a heat storage and discharge device 4. It is arranged between the butterfly valves 3.

The burner 2, which is burned in a pulsed form, has two adjacent conduits 6 and 7 internally treated with refractory material, the outer casing of which is made of steel.

The conduit 7 forms a cylindrical combustion chamber 8 adapted to receive fuel from the device 9 serving as a fuel injector and pilot burner, respectively, during the combustion and non-combustion phases. The conduit 7 has an inlet 10 adapted to receive main combustion air for burning fuel supplied by the pilot burner / fuel injector device 9 during the combustion phase. The conduit 6 forms an outlet 11 which is used for releasing combusted products in a furnace (not shown), which in use is arranged in a hole in the wall of the furnace.

Since the burner burned in the above-mentioned pulse forms part of the heat exchanger, it serves as a chimney used to discharge waste gas from the furnace during the period of heat release, that is, the flue period as conventionally. In this case the conduit 6 is the inlet through which the waste gas exits the furnace and the conduit 7 is the outlet for discharging the waste gas to the remainder of the heat exchanger 1.

The waste gas heats the heated or unheated heat storage and discharge device 4, where the heat storage and discharge device 4 releases the stored heat so that the main fuel burns during the subsequent combustion phase. The main combustion air is preheated to assist in the operation.

The conduit 7 is adjacent to the other conduit 12 and the inlet 10 has a larger diameter at the tip than the diameter of the combustion chamber 8 to increase the rate at which main combustion air is supplied to the combustion chamber 8. There is a bore tapered towards the combustion chamber 8 to be small. Similarly at the outlet 11 there is a bore tapered away from the combustion chamber 8 to accelerate the speed of the combusted product from which it is fed into the furnace.

The combustion chamber 8 is formed of a cylindrical bore portion of the conduit 7 adjacent to the inlet 10 and the outlet 11, the diameter of the portion adjacent to the combustion chamber 8 on the outlet 11 side being combusted. Approximately equal to the diameter of the chamber 8.

Since the butterfly valve 3 at the other end of the heat exchanger is closed during the combustion cycle, the air from the air inlet 5 is preheated and discharged to preheat the air to be combusted with the fuel in the combustion chamber 8. Via (4), it flows toward the burner (2) which is ignited in a pulse form.

During the pluing cycle, the butterfly valve 3 is opened so that waste gas and main combustion air are released through the other end of the heat exchanger 1 and nothing comes to the burner 2 which is ignited in a pulsed manner. See the position shown in Figure 1)

In FIG. 2, the pilot burner / fuel injector device 9 is composed of a pipe 20 having a side pipe 21 formed therein, and inside the end of the side pipe 21, a pre-mixed fuel is mixed with pilot air. The thread is formed so that the inlet pipe 22 formed with a thread to the outer end to receive.

One end of the body portion 23 of the pipe 20 is formed with a thread to enter the outlet pipe 24 is a thread formed on the outer end, the other end of the mounting mounting threaded ignition electrode 26 (25) enters. The outlet pipe 24 is in communication with the combustion chamber 8 via a bore 27 in the wall of the conduit 6.

The outlet pipe 24 is held in a sleeve 28 which is welded to the outer steel case 29 of the conduit 6. Another bore 30, which extends through the wall of the conduit 6, is connected to the bore 27 at a right angle at a position lying between the wall of the combustion chamber 8 and the outlet pipe 24 so that the flame is removed as conventional. It provides a port that can be viewed visually.

Bore 30 is provided with see-through tube 31. Combustion chamber 8 or pilot burner / fuel injector device visually through the see-through tube 31 or with an ultraviolet flame detector 32 suitably disposed at the end of the see-through tube 31 installed outside the combustion chamber 8. The flame at the exit of (9) may be detected. The pipe 40 used to supply a premix of fuel and pilot level air to the inlet pipe 22 of the pilot burner / fuel injector device 9 is schematically illustrated in FIG. 2.

Fuel (in this case, natural gas) is supplied from the fuel gas supply 41 to the pipe 40 via the main fuel gas pipe 42 and the outlet 43 of the mixing chamber 44, and the mixing chamber ( In 44, the fuel and air supplied at the pilot ratio are premixed.

Fuel gas is also supplied from the fuel gas supplier 41 to the inlet 46 of the mixing chamber 44 via the pilot fuel gas pipe 45. The pilot ratio air is supplied from the air supply 47 to the inlet 49 of the mixing chamber 44 via the pilot air pipe 48.

The main fuel gas pipe 42 includes a main fuel gas open / close solenoid valve 50 and a control valve 51, and the control valve 51 regulates the pressure of the main fuel gas used to supply the main flame. The pilot fuel gas open / close solenoid valve 50 is opened during the combustion stage and closed during the non-combustion stage, ie the pouring stage.

The pilot fuel gas pipe 45 includes an open / close solenoid valve 52, a gas pressure regulator 53 and a control valve 54, which control the pilot pressure gas pressure used to supply the pilot flame. Adjust

The pilot fuel gas open / close solenoid valve 52 is open during both the combustion phase and the non-combustion phase. However, when it is detected by the UV flame detector 32 that there is no flame during the operation, the open / close solenoid valves 50 and 52 are of course closed.

The pilot air pipe 48 has only a control valve 55 for adjusting the pilot air pressure. This maintains a constant pressure to keep the air supply rate constant. Therefore, pilot air is supplied continuously during operation. The mixing chamber 44 is a venturi type capable of mixing the pilot fuel and air well. The mixture of pilot fuel and pilot air is mixed with the main fuel gas supplied by the main fuel gas pipe 42 at the junction 56 in the pipe 40 after exiting the outlet 43 of the mixing chamber 44. (During the combustion phase).

The amount of air supplied by the inlet 49 of the mixing chamber as described above may assist the pilot fuel gas to be combusted to allow pilot flames to be generated at the exit of the pilot burner / fuel injector device 9. Should be enough. However, the amount of air must be insufficient to assist the combustion of the main fuel gas supplied by the main fuel gas pipe 42 during the combustion step. The fuel gas supplied at this ratio can continue to burn as long as there is main combustion air in the combustion chamber 8 of the burner.

The premixed mixture of fuel / air supplied by the pipe 40 during the combustion phase to prevent natural combustion of fuel, especially natural gas, should contain less than 5% air for the total volume of fuel and air. We know that The lower limit is about 2% here. In order to generate a pilot flame, there must be enough air to meet the stoichiometric combustion requirements of the fuel supplied at the pilot ratio.

Fuel during the combustion phase (when fuel is supplied through both the main fuel gas pipe 42 and the inlet 46 of the mixing chamber) and during the non-combustion phase (when fuel is supplied only to the inlet 46 of the mixing chamber). It is preferable that the ratio of the amount supplied is 30: 1 to 50: 1 and the ratio of 33: 1 is, of course, that the amount of pre-mixed pilot air is selected to satisfy the above-mentioned requirements for generating a pilot flame. Set by quantity

In FIG. 2, within the outlet pipe 24 of the pilot burner / fuel injector device 9, the pilot flame produced by the pilot burner / fuel injector device 9 during the non-combustion stage is located at the end of the outlet pipe 24. A pilot flame preservation member 57 is provided for storing. The pilot flame preservation member 57 has a stub pipe 58 that is regularly spaced within the inner wall of the outlet pipe 24.

The rear end of the stub pipe 58 is surrounded by an annular flange 59 that engages with the inner wall of the outlet pipe 24, and a plurality of holes 60 are formed at regular intervals around the circumference of the annular flange 59. There is this. Therefore, the mixture of fuel gas and air reaches the outlet via the stub pipe 58 and the annular flange 59.

The mixture of fuel gas / air is ignited by an ignition electrode 26 extending through pipes 23 and 24. The tip 60 'of the ignition electrode 26 is in the stub pipe 58, and the tip 60' discharges sparks to the stub pipe 58 forming the earth to be discharged.

When using the pilot burner / fuel injector device 9, the flame at the outlet of the outlet pipe 24 is between the main level and the pilot level because the main fuel is periodically supplied by the main fuel gas pipe 42 during the combustion phase. It is adjusted. Therefore, only when the main combustion air is supplied to the combustion chamber 8, only the main flame extends into the combustion chamber 8 of the burner. Therefore, the flame contracts and expands alternately between its main flame level and the pilot flame level.

It is not necessary to turn off the pilot flame even during the non-combustion phase, and the role of the pilot burner and the fuel injector is effectively performed in one unit, so the pilot flame is blocked to provide an adjacent fuel injector when operating as a pilot burner. You do not need to control it precisely.

As described later in detail with respect to FIG. 3, the operation of the main fuel gas open / close solenoid valve 50 and the pilot fuel gas open / close solenoid valve 52 are controlled by the ultraviolet flame detector 32. As shown in FIG.

The UV flame detector 32 does not detect any flame (pilot flame) in the outlet pipe 24 of the pilot burner / fuel injector device 9 during the non-combustion phase or any flame in the combustion chamber 8 during the combustion phase. When (coin flame) is not detected, all types of gas are not allowed to enter the burner 2 because all the solenoid valves 50 and 52 are closed. The burner will stop working.

In FIG. 1 again, at the other end of the heat exchanger there is a steel conduit 70, the opening of which serves as an outlet used to discharge waste gas (and air) from the heat exchanger 1. There is 71. Conduit 70 has a vertical conduit portion 72 including an outlet opening 71 and a horizontal conduit portion 73 connected to another portion of the heat exchanger.

The vertical conduit portion 72 comprises an upper cylindrical conduit portion 74 comprising an outlet opening 71 and a butterfly valve 3, a lower cylindrical conduit portion 75 connected to a horizontal conduit portion 73, the upper and lower portions. Conical conduit portion 77 connecting the central cylindrical conduit portion 76 having a narrower cross section than the cylindrical conduit portions 74 and 75, and the central cylindrical conduit portion 76 of the lower cylindrical conduit portion 75. And a conical conduit portion 78 connecting the upper cylindrical conduit portion 74 and the central cylindrical conduit portion 76.

The butterfly valve 3 has vanes 79 and 80 and is rotatably mounted in the upper cylindrical conduit 74. When the butterfly valve 3 is in the closed state, the wings 79 and 80 engage with a pair of semi-circular seals 81 and 82 that are secured to the wall of the upper cylindrical conduit 74.

The semicircular seal 82 is offset from the semicircular seal 81 at a right angle to a substantially horizontal plane. In this way, when the butterfly valve 3 is closed, the waste gas cannot be discharged through the outlet opening 71.

When the butterfly valve 3 is rotated in the open state as shown in FIG. 1, waste gas flowing through the conduit 70 toward the outlet opening 71 is discharged through the outlet opening 71. A solenoid actuator (not shown) may be used to open and close the butterfly valve 3. The air injector 5 has a pipe 83 with a vertical portion 84 extending into the vertical conduit portion 72 through the horizontal wall of the horizontal conduit portion 73.

The end of the pipe 83 extends into the nozzle 85. The end 86 of the nozzle 85 extends to the conical conduit portion 77, the outer surface of the nozzle end of which is the body of the nozzle 85 fixed to the end of the vertical portion 84 of the pipe ( The taper is under-formed upwards from 87.

Since the bore of the nozzle 85 is compressed, the air supplied to the vertical portion 84 of the pipe is accelerated when it leaves the vertical portion 84 of the pipe.

During the pluing step, such air is conduit 70 because there is a venturi-type narrowed conduit portion formed in conduit 70 by a central cylindrical conduit portion 76 of the conduit, and a conical conduit portion 77, 78. A suction effect having a tendency to suck the waste gas of the furnace which enters the burner 2 toward) is generated, which accelerates the removal of the waste gas from the furnace and accelerates the transfer of the waste gas to the outlet opening 71.

If the waste gas enters the narrow central cylindrical conduit portion 76 when the butterfly valve 3 is open, the air discharged from the nozzle 85 tends to blow off the waste gas to vent the waste gas through the outlet. Air is supplied to a pipe 83 from a suitable air supply 69, for example a compressed air source.

The air supply 47 for the pilot air control valve 55 shown in FIG. 2 also serves as a compressed air supply source. The air supply 69 is connected to the pipe 83 by a pipe 88 which is coupled to the open / close solenoid valve 89. The auxiliary pipe 90 to which the control valve 91 is coupled is connected across the open / close solenoid valve 89.

When the open / close solenoid valve 89 is open, the air flows at high speed to provide a sufficient amount of main combustion air to assist in burning the main fuel supplied by the pilot burner / fuel injector device 9 during the combustion phase. It is supplied to the pipe (83).

Even during the pouring cycle, it continues to flow at high speed as above to help the waste gas entering the burner 2 to be expelled to preheat the heat storage and discharge device 4 as described above. When the open / close solenoid valve 89 is closed, air is supplied by the auxiliary pipe 90 at a rate controlled by the control valve 91.

This controlled rate of air supply is very small compared to the main flow air supply and represents the so-called atmospheric rate when the heat exchanger is in the standby state. When placed in this standby state, the burner 2 is maintained between the combustion phase and the pouring phase and is simply waiting for combustion or non-combustion without being in a combustion state or a flying state.

When operated in this manner the pilot burner / fuel injector device 9 of the burner generates a pilot flame and the butterfly valve 3 is closed. The small amount of air from the air nozzle end 86 serves to transfer waste gas generated by the pilot flame to the furnace.

The heat storage and dissipation device 4 has a heat storage bed 100 made of a heat storage packing material formed of particles of refractory material, as shown, and loosely disturbed. A gaseous fluid is allowed to flow in any direction through the heat storage bed 100. The heat storage bed 100 is contained within a steel conduit 101 embedded with refractory material, the lower end of the steel conduit 101 is connected to the branch conduit 102 and the upper end is connected to the conduit 12.

At the bottom of the steel conduit 101 is a cylindrical bore chamber portion 103 that encloses the heat storage bed 100. The cylindrical bore chamber portion 103 is in communication with the conical tapered middle bore portion 104, the end of the middle bore portion 104 is in the upper bore portion 105, and the upper bore portion 105 is cylindrical. And its diameter is smaller than the diameter of the cylindrical bore chamber portion 103.

The lower end of the outer steel case of the steel conduit 101 extends to the flange 106, which is connected to the branch pipe 102, on which the steel ring 107 is placed. The steel ring 107 is buried in the inner surface of the refractory lining 108 to support the grid of metal 109, which supports the heat storage bed 100.

The branch pipe 102 has a full high pressure chamber 110 that is directed to the horizontal conduit 111 so as to be in communication with the horizontal conduit portion 73 of the conduit 70. The full high pressure chamber 110 has an opening 112 which communicates with the lower end of the chamber portion 103 rather than the cylindrical shape of the steel conduit 101.

The connecting conduit 12 connects the heat storage steel conduit 101 and the burner conduit 7, and the connecting conduit 12 is connected to the vertical part 114 connected to the steel conduit 101 and the burner conduit 7. It has a horizontal portion 115, the refractory material is embedded and includes a steel conduit 113 of a right angle.

The vertical portion 114 of the conduit has a bore 116 of approximately the same diameter as the adjacent upper bore portion 105 of the steel conduit 101 and the horizontal portion 115 of the conduit has a diameter of the inlet of the conduit 7. There is a bore 117 that is approximately equal to the largest diameter portion of 10.

In Fig. 3, the same numbers are used for parts similar to those shown in Figs. 1 and 2, with "A" attached to one heat exchanger and "B" attached to another heat exchanger. .

OR gates 130A and 130B control pilot fuel gas open and close solenoid valves 52A and 52B, and AND gates 131A and 131B are main fuel gas open and close solenoid valves 50A ( 50B), and the OR gates 132A and 132B control the main air open / close solenoid valves 89A and 98B.

Enabling signal from ora gate 130 opens pilot air conditioning valves 55, and enabling signal from and gate opens main fuel gas open / close solenoid valves 50 and ora gate The enabling signal from 132 opens the main air open / close solenoid valves 89.

Pilot fuel gas ora gates 130A and 130B are enabled by signals from ultraviolet flame detectors 32A and 32B or signals from start-up overrides 133A and 133B. Lose.

The main fuel gas and gates 131A and 131B are enabled when there is a signal from the UV flame detectors 32A and 32B and a signal from the line A or B to the combustion duration timer 134. The main air ora gate 132 is enabled when there is a signal on either line A or line B of the combustion period timer 134.

Start-up overrides 133A and 133B are both conventional and must be set to initiate operation. Each start-up override 133 has a burner ignition electrode 26A, 26B, when set, unlike controlling the ora gate, is released from the exit of the pilot burner / fuel prime device 9A or 9B. Sparks are generated to ignite the pilot mixture.

After a predetermined period of time, each start-up override 133 is automatically reset. The combustion period timer is also conventional and controls the combustion period of the burner. The combustion period of the heat exchanger 1A is controlled by the length of time that a signal is present in the line A of the combustion period timer 134, and the combustion period of the heat exchanger 1B is the line of the combustion period timer 134. In (B) it is controlled by the length of time the signal is present.

When there is a signal on one line of the timer, there is no signal on the other line. In this case, if one heat exchanger is burning, the other heat exchanger becomes a flying state. Periodically, the role of the heat exchanger is switched by switching the signal from one line to another.

This conversion process is automatic as the selected combustion continues. However, it is also possible to set the combustion duration timer 134 manually or automatically. In this case, each heat exchanger 1 may assume that the heat exchanger is in a standby state, neither in combustion nor in a flying state, as described above. At this time, a pilot flame is emitted from the apparatus 9. The butterfly valve 3 is controlled by valve actuators 135A and 135B. The valve actuator is a solenoid or similar device.

In the arrangement of FIG. 3, the valve actuator 135A causes the valve actuator 135A to actuate to open the butterfly valve 3A when there is a signal on the line of the combustion period timer 134. Controlled by line B of 134. Similarly, valve actuator 135B is configured to activate the combustion period timer 134 so that valve actuator 135B is actuated to open butterfly valve 3B when there is a signal in line A of combustion period timer 134. It is controlled by the line A of.

The butterfly valve 3 is of course closed when there is no signal in the control line of the timer. The air for pilot burner / fuel injectors 9A, 9B and air injectors 5A, 5B is supplied by a central air supply 136. The fuel gas for the pilot burner / fuel injector device 9A, 9B is supplied by the central fuel gas supplier 137.

Start-up overrides 132A and 132B must be set to operate the system described above. This causes the pilot fuel gas open / close solenoid valves 52A and 52B to be opened so that the pilot fuel gas and the pilot air are mixed in the mixing chambers 44A and 44B. The mixing chambers 44A and 44B are continuously supplied with pilot air by the pilot air control valves 55A and 55B.

When the start-up overrides 133A and 133B are set, current flows in the lines 138A and 138B, causing the ignition electrode 26 in the pilot burner / fuel injector device 9A and 9B to spark, causing the mixing chamber ( The pilot burner / fuel injection from 44A) 44B will ignite a mixture of pilot fuel and pilot air entering the apparatus 9A, 9B.

This causes the pilot burner / fuel injector device 9A, 9B to generate a pilot flame and the start-up overrides 133A and 133B are automatically reset. When the heat exchanger 1A is under combustion and the heat exchanger 1B is under flue, then a signal is present in line A of the combustion period timer 134 and a signal is present in line B of the combustion period timer 134. does not exist.

Because the ultraviolet flame detector 32A detects the pilot flame from the pilot burner / fuel injector device 9A and there is a signal on line A of the combustion period timer, the end gate 131A is enabled and the main fuel gas open / close solenoid The valve 50A is opened to allow the main fuel gas to mix with the mixture of pilot gas and pilot air flowing down the mixing chamber 44A.

Additionally, because there is a signal in line A of combustion duration timer 134, Oh gates 132A and 132B are enabled to allow main air open / close solenoid valves 89A and 89B in the heat exchanger to open.

Finally, because valve A has a signal on line A of combustion duration timer 134 and no signal on line B, valve actuator 135B is activated to open butterfly valve 3B, but valve actuator 135A The butterfly valve 3A is left inoperative so as to be closed.

As a result, the main air in the heat exchanger 1A flows into the combustion chamber of the burner via the heat storage bed to assist in the combustion of the mixture of main fuel gas and pilot air from the outlet of the device 9A. The pilot flame therefore extends to the level of the main flame in the combustion chamber.

The resulting combustion products enter the furnace to heat the enclosure of the furnace. Since the butterfly valve 3B is open, the main air in the heat exchanger 1B leaves the heat exchanger 1B via the outlet opening 71B. The waste gas generated by the burner of the heat exchanger 1A enters the heat exchanger 1B and passes through the heat storage bed through the heat storage bed by the suction effect caused by the injection of the main air. It is drawn into the venturi formed by 78. Therefore, the bed is preheated by the waste gas which is eventually released through the outlet opening 71B with the help of the main air.

When the heat exchanger 1B is in combustion, the heat exchanger 1A should be flying. In this case, there is a signal on line B, but there is no signal on line A. In this case, of course, since the main fuel gas open / close solenoid valve 50B is opened by an enable signal from the end gate 131B, and the main fuel gas open / close solenoid valve 50A has no enable signal at the end gate 131A. To be closed.

However, since the oar gates 132A and 132B are enabled by the signal from the line B of the timer, the main air open / close solenoid valves 89A and 89B remain open.

However, since the valve actuator 135B is no longer actuated by the signal in line A of the timer, the butterfly valve 3B is closed and the valve actuator 135A is in line B of the combustion duration timer. The butterfly valve 3A is open because it is actuated by a signal.

In this case, therefore, the pilot flame in the pilot burner / fuel injector device 9B extends to the main flame level supplying combustion products to the furnace, and the flame in the pilot burner / fuel injector device 9A causes it to shrink to the pilot level. do.

The main air used to burn the mixture of the main fuel and the pilot air in the pilot burner / fuel injector device 9B is of course preheated by the heat from the preheated heat storage bed in the heat exchanger 1B.

The waste gas entering heat exchanger 1A preheats the heat storage bed before exiting through outlet opening 71A in heat exchanger 1A. During operation, for example, the heat exchanger 1A and 1B can be set to the standby state when it is necessary to terminate the instantaneous combustion because the inside of the furnace has risen to a temperature that is instantaneously required. In this case, since there are no signals in the lines A and B of the timer, the AND gates 131A and 131B are not enabled and the main fuel gas open / close solenoid valves 50A and 50B are closed.

When the pilot flame is detected by the ultraviolet flame detectors 32A and 32B, the pilot fuel gas open / close solenoid valves 52A and 52B are opened because the ora gates 130A and 130B are enabled.

The main air open / close solenoid valves 89A and 89B are closed because no signal is present in the lines A and B of the combustion period timer, so that the OR gates 132A and 132B are not enabled.

Similarly, the butterfly valves 3A and 3B are closed because the valve actuators 135A and 135B do not operate. As a result, the pilot burner / fuel injector device 9A, 9B is operated in pilot mode and the air is exchanged from the air injector 5 via the control valves 91A, 91B via the heat exchanger 1A, 1B. It is supplied little by little.

It simply serves to assist the transfer of combustion products from the pilot flame into the furnace. If the main flame in the heat exchanger is turned off for some reason during combustion, the main fuel gas open / close solenoid valve is automatically closed because the end gate 131 is no longer enabled.

Similarly, the pilot fuel gas open / close solenoid valve 52 is also closed because the oar gate 130 is no longer enabled. If no flame is detected during the pluing phase or the standby state, the pilot fuel gas open / close solenoid valve 52 is also closed because the oar gate 130 is no longer enabled.

To reactivate, the relevant start-up override 132 must be reset.

Claims (17)

Adjust the fuel supply rate to the pilot level during the non-combustion stage and to the main flame level during the combustion phase to generate flame, and to a pilot level sufficient to maintain combustion of the fuel at the pilot ratio to premix with the fuel before ignition. Supplying air, premixing fuel and air, and stopping the supply of fuel when a flame is not detected. 2. A method according to claim 1, wherein the amount of air premixed with the fuel in the main ratio is 5% or less of the total volume of fuel and air. 3. A method according to claim 2, wherein the amount of air premixed with the fuel at the main rate is at least 2% of the total volume of fuel and air. The method according to any one of claims 1 to 3, wherein the ratio of the amount of fuel supplied to the main level and the amount of fuel supplied to the pilot level is between 30: 1 and 50: 1. 5. The method of claim 4 wherein the ratio is 33: 1. 2. The pilot fuel gas open / close solenoid valve of claim 1, wherein the fuel is supplied at a pilot ratio by the pilot fuel gas open / close solenoid valve so that the fuel is premixed with the pilot air, and the fuel is subsequently mixed with the mixture of pilot fuel and air. Main fuel gas on-off solenoid valves can be closed during noncombustion cycles, and both pilot fuel gas on-off solenoid valves and main fuel gas on-off solenoid valves can be closed when no flame is detected. Characterized in that the method. 7. A fuel cell according to claim 6, wherein the pilot ratio fuel and the pilot air are mixed in the mixing chamber, and the pilot fuel and air mixture is followed by the main ratio fuel when the main ratio fuel is supplied by the main fuel gas open / close solenoid valve. Characterized in that it is mixed. 8. A method according to claim 6 or 7, wherein the pilot fuel gas open solenoid valve and the main fuel gas open solenoid valve are both supplied with fuel from the same fuel source. The method of claim 1, wherein the air is supplied at a pilot rate by the control valve. The method of claim 1, wherein air is supplied at a constant rate. A device that adjusts the fuel supply rate to the pilot level during the non-combustion phase and to the main flame level during the combustion phase, a pilot sufficient to maintain combustion of the fuel at a pilot rate to premix with the fuel prior to ignition to generate flame. An apparatus for operating a pulsed burner, comprising a device for supplying air to a level, a device for pre-mixing fuel and air, and a device for stopping fuel supply when a flame is not detected. 12. The apparatus of claim 11, wherein the device for adjusting the fuel supply ratio includes a valve device that is operated to adjust the fuel supply ratio between the two ratios of the pilot flame level and the main flame level and to close when no flame is detected. Device characterized in that. 13. The pilot fuel gas open / close solenoid valve of claim 12, wherein the valve device supplies fuel at a pilot ratio to premix with the pilot air, and the main fuel for main ratio to be subsequently mixed with the mixture of pilot fuel and air. A fuel gas open / close solenoid valve is configured, and the main fuel gas open / close solenoid valve can be closed during a non-combustion cycle, and when the flame is not detected, the pilot fuel gas open / close solenoid valve and the main fuel gas open / close solenoid valve can be closed in advance. Device characterized in that the. 14. The apparatus of claim 13, wherein the device for premixing the fuel with air comprises an inlet adapted to receive fuel from the pilot fuel gas open / close solenoid valve, an inlet adapted to receive pilot air, and a main fuel supplied by the main fuel gas open / close solenoid valve. And a chamber constituting an outlet for releasing a mixture of pilot fuel and air for subsequent mixing. 15. The apparatus according to claim 13 or 14, wherein the pilot fuel gas open solenoid valve and the main fuel gas open solenoid valve receive fuel from the same fuel source. The device according to claim 11, wherein the device for supplying air at a pilot ratio is constituted by a control valve. 17. The apparatus of claim 16, wherein the control valve is adapted to supply pilot air at a constant rate.

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