JP6893731B2 - Burner - Google Patents

Description

The present invention relates to a pressure spray burner for liquid fuel, and more particularly to a burner used for a dryer for heating aggregate in an asphalt plant.

In recent years, in producing asphalt mixture, from the viewpoint of effective utilization of resources, asphalt pavement waste material (hereinafter referred to as "waste material") generated by road construction etc. is mixed with new aggregate in a predetermined ratio. In many cases, the mixing rate is as high as about 70 to 80%. When producing an asphalt mixture in which waste material is mixed in a high proportion as described above, the amount of new aggregate in the asphalt mixture is relatively reduced, and the burner combustion amount of the new aggregate heating dryer is correspondingly reduced. Since it is necessary to reduce the amount of combustion in normal operation without mixing waste materials, the burner of the new aggregate heating dryer has a large turndown ratio (ratio of minimum combustion amount to maximum combustion amount). Things (for example, about 1: 8) are often required.

However, in a burner with such a high turndown ratio, if combustion is performed near the minimum combustion amount, the amount of combustion air will be extremely smaller than in normal times, resulting in a decrease in the flow velocity of the combustion air. In some cases, the fuel oil and the combustion air cannot be sufficiently stirred and mixed, and there is a concern that it becomes difficult to form a stable flame.

On the other hand, for example, in Patent Document 1 (Japanese Patent Laid-Open No. 9-310813) and Patent Document 2 (Japanese Patent Laid-Open No. 2009-41816), the burner body has a double cylinder structure and an annular secondary air flow rate is provided. A passage is provided, and the annular secondary air flow path is provided with a flow rate adjusting damper that adjusts the amount of secondary air passing through, and a burner that controls opening and closing of the flow rate adjusting damper according to the amount of burner combustion is described. Has been done. According to the burner, even during low combustion when the amount of combustion air is small, by narrowing the flow path for the secondary air, it is possible to suppress a decrease in the flow velocity of the combustion air (primary air) passing around the fuel injection nozzle. Therefore, it is possible to form a stable flame without deteriorating the stirring and mixing performance of the fuel oil and the combustion air.

Japanese Unexamined Patent Publication No. 9-310813 JP-A-2009-41816

However, in the conventional burner, since the secondary air flow path has an annular structure, a plurality of flow rate adjusting dampers for opening and closing the flow path are arranged at predetermined intervals along the annular flow path. At the same time, each damper is connected to each other by, for example, a link mechanism, and the opening and closing control is performed while synchronizing each damper, which is structurally a little complicated and somewhat disadvantageous in terms of manufacturing cost and maintenance. It has become.

In view of the above points, it is an object of the present invention to provide a burner having a high turndown ratio capable of forming a stable flame while having a relatively simple configuration.

Burner of claim 1, wherein according to the present invention connects the small diameter portion side of the throat having a throat body of截head conical hollow in the front end opening portion of the burner body of a single cylinder structure, the inner diameter of the burner body A flame-retaining plate having the same diameter and an annular shape and a fuel injection nozzle located behind the flame-retaining plate are provided, and the flame-retaining plate allows advancing and retreating in the throat body along the longitudinal direction of the burner body. The fuel injection nozzle is movable back and forth with respect to the central opening of the flame holding plate, and the burner body is provided with a static pressure sensor for detecting the internal static pressure, and is based on the static pressure value detected by the static pressure sensor. The first-stage static pressure adjustment control for adjusting the gap between the outer edge of the flame-retaining plate and the inner peripheral wall of the throat body by advancing and retreating the flame-retaining plate and the fuel injection nozzle in synchronization with each other, and the flame-retaining plate. two made from a second stage static pressure adjustment control for finely adjusting the gap distance between the fixed and the fuel injection nozzle only be allowed in the fuel injection nozzle and flame holding plate central opening advance and retract at the proximal end portion of the throat It is characterized in that a flame is formed while maintaining the static pressure inside the burner body at a predetermined value by stepwise static pressure control.

Further, in the burner according to claim 2, the static pressure value at an arbitrary combustion amount that can maintain stable flame formation is set as the set static pressure value inside the burner main body, and the static pressure value is detected by the static pressure sensor. It is characterized in that the two-step static pressure control is performed only when the pressure value falls below the set static pressure value.

Further, in the burner according to claim 3, a flow rate sensor for detecting the flow rate of the fuel supply pipe that supplies fuel to the fuel injection nozzle and an air volume sensor for detecting the amount of air blown by the blower that supplies combustion air to the burner body. And an air volume adjusting means for adjusting the air volume of the blower, the set air volume corresponding to a predetermined air ratio with respect to the fuel supply amount detected by the flow rate sensor and the actual air volume sensor detected by the air volume sensor. It is characterized in that the air flow rate of the blower is adjusted and controlled via the air flow rate adjusting means based on the difference value from the air flow rate.

According to the burner of claim 1, wherein according to the present invention, to connect the throat with a throat body of截head conically shaped distal end opening portion of the burner body, an annular flame holding plate inner diameter and the same diameter of the burner body The burner body is provided with a static pressure sensor for detecting the internal static pressure, and the flame holding plate and the flame holding plate are provided based on the static pressure value detected by the static pressure sensor. The first stage static pressure adjustment control that adjusts the gap between the outer edge of the flame holding plate and the inner peripheral wall of the throat body by advancing and retreating while synchronizing with the fuel injection nozzle, and the flame holding plate at the base end of the throat. The burner body is controlled by two-step static pressure, which consists of a second-step static pressure adjustment control that finely adjusts the gap between the center opening of the flame holding plate and the fuel injection nozzle by fixing and advancing only the fuel injection nozzle. Since the flame is formed while maintaining the internal static pressure at a predetermined value, it is for combustion that is injected from inside the burner body through the vicinity of the fuel injection nozzle even during low combustion when the amount of combustion air is small. The jet flow velocity of air can be kept substantially constant, and stable flame formation is possible with a relatively simple configuration.

Further, according to the burner according to claim 2, the static pressure value at an arbitrary combustion amount that can maintain stable flame formation is set as the set static pressure value inside the burner main body, and is detected by the static pressure sensor. Since the two-step static pressure control is performed only when the static pressure value to be applied falls below the set static pressure value, the set static pressure value is, for example, the amount of combustion near the lower limit in which stable flame formation can be maintained. By setting the static pressure value at the time, the flame holding plate and the fuel injection nozzle can be advanced and retreated only within the range of the low combustion region where the flame formation becomes unstable, thereby causing the flame holding plate and the fuel. The adjustment margin for advancing and retreating the injection nozzle can be used more effectively, fine adjustment becomes possible, and stable flame formation becomes possible.

Further, according to the burner according to claim 3, a flow rate sensor for detecting the flow rate of the fuel supply pipe that supplies fuel to the fuel injection nozzle and a blower for detecting the amount of air blown by the blower that supplies combustion air to the burner body. It is provided with an air volume sensor and an air volume adjusting means for adjusting the air volume of the blower, and detects with the air volume sensor and a set air volume corresponding to a predetermined air ratio with respect to the fuel supply amount detected by the flow rate sensor. Since the amount of air blown by the blower is adjusted and controlled based on the difference from the actual amount of air blown, it is set from the blower due to the increase in air resistance that accompanies the adjustment in the direction in which the flow path of the combustion air narrows. Even if the air cannot be blown to the burner body according to the air flow rate and the air flow rate actually supplied is less than the predetermined air ratio with respect to the fuel supply amount, the air volume corresponding to the shortage is sequentially compensated. The amount of air blown by the blower can be adjusted to enable stable flame formation.

It is a schematic explanatory drawing which shows one Example of the burner which concerns on this invention. It is a burner sectional view which shows the positional relationship between a flame holding plate and a fuel injection nozzle at the time of the maximum combustion amount. It is a figure corresponding to FIG. 2 at the time of the intermediate combustion amount (when the flame holding plate retracts). It is a figure corresponding to FIG. 2 at the time of the intermediate combustion amount (when the flame holding plate is fixed). It is a figure corresponding to FIG. 2 at the time of the minimum combustion amount.

In the burner according to the present invention, a throat having a hollow, substantially conical throat body so as to have a tapered structure in which the inner diameter gradually expands at the tip opening of the burner body having a single cylinder structure. Connect the small diameter side. Further, a fuel injection having a diameter substantially the same as the inner diameter of the burner main body and an annular flame holding plate and a fuel injection located behind the flame holding plate (on the burner main body side) at a predetermined interval to inject liquid fuel such as heavy oil. The flame-retaining plate is provided with a nozzle so that the flame-retaining plate can advance and retreat in the throat body along the longitudinal direction of the burner body, while the fuel injection nozzle can advance and retreat with respect to the central opening of the flame-retaining plate.

Further, the burner main body is provided with a static pressure sensor for detecting the internal static pressure, and based on the static pressure value detected by the static pressure sensor, the flame holding plate and the fuel injection nozzle are moved forward and backward while synchronizing. First-stage static pressure adjustment control that adjusts (primary adjustment) the static pressure inside the burner body by narrowing the gap between the outer edge of the flame holding plate, which is a part of the flow path of combustion air, and the inner peripheral wall of the throat body. When the static pressure value inside the burner body cannot be adjusted to a predetermined value even if the flame holding plate is fully retracted to the base end of the throat, the flame holding plate is fixed at the base end of the throat and then held. The fuel injection nozzle is advanced and retracted so as to move away from the center opening of the flame plate so as to move away from each other, and the gap between the center opening of the flame holding plate and the fuel injection nozzle, which is a part of the flow path of the combustion air as described above. By the second stage static pressure adjustment control that finely adjusts (secondary adjustment) the static pressure inside the burner body by squeezing, the static pressure inside the burner body is set to a predetermined value, for example, the static pressure value at the maximum combustion amount (maximum). Try to form a flame while maintaining the static pressure value).

As the set static pressure value inside the burner body, a static pressure value at an arbitrary combustion amount that can maintain stable flame formation without narrowing the gap spacing is set in advance and detected by the static pressure sensor. The two-step static pressure control may be performed only when the static pressure value to be applied is lower than the set static pressure value.

At this time, if the set static pressure value is set, for example, the static pressure value at the time of combustion amount near the lower limit where stable flame formation can be maintained, the detection value of the static pressure sensor exceeds the set static pressure value for high combustion. In the region, the flame holding plate and fuel injection nozzle do not move forward and backward, and only when the detection value of the static pressure sensor falls below the set static pressure value, that is, within the range of the low combustion region where flame formation becomes unstable. The flame holding plate and the fuel injection nozzle are moved forward and backward in a limited manner to adjust and control the inside of the burner body so as to return and maintain the set static pressure value. Can be used more effectively to make fine adjustments.

Further, preferably, the flow rate sensor for detecting the flow rate of the fuel supply pipe that supplies fuel to the fuel injection nozzle, the air volume sensor for detecting the air flow rate of the blower, and the air volume sensor of the blower are adjusted, for example, an inverter type. The difference between the set air volume corresponding to the predetermined air ratio to the fuel supply amount detected by the flow rate sensor and the actual air volume detected by the air volume sensor. The air flow rate of the blower may be adjusted and controlled via the air flow rate adjusting means based on the amount.

In this way, due to the increase in air resistance that accompanies the adjustment of the combustion air flow path in the narrowing direction, it is not possible to blow air to the burner body according to the set air flow rate by the blower, and the air flow rate actually supplied. Even if the air volume is less than the predetermined air ratio, the air volume of the sequential blower can be corrected so as to supplement the air volume corresponding to the shortage, and stable flame formation becomes possible.

Then, during operation of the burner having the above configuration, for example, when the burner combustion amount is lowered from the maximum combustion state, the static pressure in the burner body decreases with the amount of air blown from the blower, but the static pressure sensor detects it. Then, first, as the first stage static pressure adjustment control, the flame holding plate and the fuel injection nozzle are retracted together while synchronizing. Since the inner diameter of the throat body has a tapered structure that gradually shrinks toward the rear (burner body side), the outer edge of the flame retaining plate, which is a part of the flow path of the combustion air as the flame retaining plate retracts. The gap between the throat and the inner peripheral wall of the throat body gradually narrows, the internal static pressure rises, and the original predetermined static pressure value (for example, the maximum static pressure value) is restored and maintained.

If the internal static pressure cannot be adjusted to the original predetermined static pressure value even if the flame holding plate is completely retracted to the throat base end, the flame holding plate is used as the throat base end as the second stage static pressure adjustment control. After fixing it so that it does not move, only the fuel injection nozzle is advanced so as to be close to the central opening of the flame holding plate by switching the traveling direction. When the flame retaining plate is completely retracted to the base end of the throat, a part of the flow path of the combustion air is substantially closed, and in that state, the fuel injection nozzle is brought close to the central opening of the flame retaining plate. The flow path of the combustion air can be further narrowed to finely adjust the static pressure (secondary adjustment), and the inside of the burner body can be restored and maintained at the original predetermined static pressure value even in a lower combustion region.

By adopting the two-step static pressure control as described above, the injection flow velocity of the combustion air injected from the burner body can be set to that at the time of high combustion amount even in the vicinity of the minimum combustion amount where the amount of combustion air becomes extremely small. It can be maintained at the same level, and stable flame formation is possible without deteriorating the stirring mixture of the fuel oil and the combustion air.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

Reference numeral 1 in the figure is, for example, a burner having a high turndown ratio of the present invention installed in an aggregate heating dryer of an asphalt plant, which is a single-cylinder burner main body 2 and a blower 3 for supplying combustion air. Is connected by a ventilation duct 4. The small diameter side of the throat 5 having a hollow and substantially conical throat body 5a is connected to the tip opening of the burner body 2 so as to have a tapered structure in which the inner diameter gradually expands. Further, a hollow rod member 6 containing a fuel supply pipe and a return pipe (not shown) is inserted into the substantially central portion (cylindrical shaft core portion) of the burner main body 2, and the rod member 6 is inserted. It is sandwiched by a plurality of guide rollers 7 from above and below, and is supported so as to be able to advance and retreat along the longitudinal direction of the burner main body 2 as shown by the thick arrow in FIG.

A fuel injection nozzle 8 is fixed to the tip of the rod member 6, and the diameter is substantially the same as the inner diameter of the burner body 2 in front of the rod member 6 via an urging means 9 such as a spring body or a gas spring. An annular flame-retaining plate 10 is attached so as to be able to move apart from each other. The distance between the fuel injection nozzle 8 and the flame holding plate 10 varies as the urging means 9 expands and contracts, but it greatly affects the flow velocity of the combustion air passing around the fuel injection nozzle 8. Therefore, it is advisable to appropriately determine the flame holding plate 10 through a combustion test or the like within a range in which an appropriate flame shape is formed regardless of whether the flame holding plate 10 is in close proximity or separated.

On the other hand, the rod base end portion 11 that penetrates the rear end portion of the burner main body 2 and protrudes rearward is connected to the fuel supply pipe 12 and the fuel so as to be connected to the fuel supply pipe and the return pipe in the rod member 6, respectively. In addition to connecting the return pipe 13, the rod member 6 is provided with advancing / retreating means 14 for advancing / retreating the rod member 6 along the longitudinal direction of the burner main body 2.

The advancing / retreating means 14 may adopt an appropriate configuration. For example, as shown in FIG. 1, a support 15 extending rearward from the rear end portion of the burner main body 2 and a shaft support parallel to the support 15. A screw shaft 16 formed of the screw shaft 16 and a stepping motor 17 or the like for rotationally driving the screw shaft 16 can be preferably adopted. Reference numeral 18 in the drawing is a connecting piece for connecting the rod base end portion 11 and the screw shaft 16, and a groove portion (screw groove) screwed with the screw groove of the screw shaft 16 is provided on the inner surface side of the connecting portion of the connecting piece 18. (Not shown) is engraved, and the screw shaft 16 is rotated forward and reverse by the stepping motor 17, so that the rod member 6 is moved to a predetermined position along the longitudinal direction of the burner body 2 via the connecting piece 18. It is possible to move forward and backward.

Further, 19 in the drawing is for airtightness to prevent high-pressure combustion air inside the burner body 2 from being ejected from a gap (not shown) at the end of two burner bodies through which the rod member 6 penetrates. It is a seal member, and in this embodiment, it has, for example, a stretchable bellows structure so as not to interfere with the advancing / retreating operation of the rod member 6.

In the figure, 20 is a static pressure sensor that detects the internal static pressure of the burner main body 2, and 21 is a static pressure / flame holding plate / fuel injection nozzle adjustment controller, and the static pressure / flame holding plate / fuel injection nozzle adjustment. The controller 21 sequentially captures the static pressure value detected by the static pressure sensor 20, and maintains the captured static pressure value at a predetermined value, for example, the static pressure value at the maximum combustion amount (for example, about 300 mmAq). The flame-retaining plate 10 at the tip of the rod member 6 is advanced and retreated within the range of the throat body 5a via the advancing / retreating means 14, and the flame-retaining plate outer edge 10a and the throat body 5a which are a part of the flow path of the combustion air. The internal static pressure of the burner main body 2 is adjusted (primary adjustment) by narrowing the gap A between the inner peripheral wall and the inner peripheral wall.

The length of the throat body 5a with respect to the total length of the throat 5 may be appropriately determined. For example, if the throat body 5a is formed to be long, the flame retaining plate outer edge portion 10a and the tapered structure can be formed. A large amount of adjustment margin for the gap A with the inner peripheral wall of the throat body 5a can be secured, and fine adjustment is possible.

Further, 22 in the drawing is a fixing means for restraining and fixing the advancing / retreating operation of the flame holding plate 10, and the fixing means 22 is, for example, a cylinder 23 provided at the base end of the throat 5 and the cylinder 23. A substantially U-shaped restraint piece 24 provided at the tip of a piston rod that expands and contracts in the direction of the axis inside the burner body 2, and combustion air is ejected from the inside of the burner body 2 to the outside when the piston rod expands and contracts. It is composed of a cover body 25 and the like to prevent it from occurring.

Then, when the internal static pressure cannot be adjusted to the predetermined value even if the flame holding plate 10 is completely retracted to the base end portion of the throat 5, the static pressure / flame holding plate / fuel injection nozzle adjustment controller 21 may be used. After extending the piston rod of the cylinder 23 of the fixing means 22 and sandwiching the outer edge portion 10a of the flame holding plate with the restraining piece 24 at the tip, the advancing / retreating operation of the flame holding plate 10 is temporarily restrained and fixed. From that state, the fuel injection nozzle 8 at the tip of the rod member 6 is moved away from the central opening 10b of the flame holding plate via the advancing / retreating means 14 while resisting the urging force of the urging means 9. By advancing and retreating to, the internal static pressure of the burner body 2 is reduced by narrowing the distance between the flame holding plate center opening 10b, which is a part of the flow path of the combustion air, and the gap B between the fuel injection nozzle 8 as described above. I am trying to make adjustments (secondary adjustments).

It should be noted that stable flame formation can be maintained in the static pressure / flame holding plate / fuel injection nozzle adjustment controller 21 without narrowing the distance between the gaps A and B as the set static pressure value inside the burner main body 2. The static pressure value at an arbitrary combustion amount is set in advance, and only when the static pressure value detected by the static pressure sensor 20 is lower than the set static pressure value, the set static pressure value is restored and maintained. It is also possible to perform the two-step static pressure control.

By adopting the control, as the set static pressure value, for example, combustion in the vicinity of the lower limit where stable flame formation can be maintained without narrowing the flow path of each combustion air, which is found through a combustion test or the like. If the static pressure value (for example, about 200 mmAq) at the time of quantity is set, the flame holding plate 10 and the fuel injection nozzle 8 do not move forward and backward in the high combustion region, but the flame formation becomes unstable. The flame holding plate 10 and the fuel injection nozzle 8 are moved forward and backward only within the range of the combustion region, and the adjustment margin of the flame holding plate 10 and the fuel injection nozzle 8 can be used more effectively to finely adjust the static pressure. It will be possible.

Further, the fuel supply pipe 12 for supplying fuel oil such as heavy oil A or kerosene to the rod member 6 has a fuel supply pump 26 and a flow sensor 27 interposed therebetween, and the other end thereof is connected to the fuel tank 28. On the other hand, the adjacent fuel return pipe 13 has a flow rate adjusting valve 29 interposed in the middle thereof, and the other end thereof is connected to the fuel supply pipe 12 on the upstream side of the fuel supply pump 26, and the flow rate is adjusted by the control motor 30. By adjusting the opening degree of the valve 29 to adjust the return amount of the fuel oil, it is possible to adjust only the injection amount without changing the injection speed of the fuel oil from the fuel injection nozzle 8 at the tip of the rod member 6 so much. There is.

Further, an intake pipe 32 having a substantially straight pipe structure is connected to the intake port 31 of the blower 3, and an air volume sensor 33 for detecting the amount of air blown is provided in the middle of the intake pipe 32, and the drive motor 34 of the blower 3 is provided. Is equipped with an inverter 35 for controlling the number of revolutions, which is a means for adjusting the amount of air blown, and by adjusting the number of revolutions of the drive motor 34 with the inverter 35, the amount of burner combustion without the need for a damper for adjusting the amount of air blown. It is possible to supply the amount of air blown to the burner main body 2 in accordance with the above.

Reference numeral 36 in the figure is a fuel / air flow rate adjustment controller, and the fuel / air flow rate adjustment controller 36 sequentially captures the fuel supply amount that is adjusted by the flow rate adjusting valve 29 and detected by the flow rate sensor 27. , The set air flow rate corresponding to a predetermined air ratio (for example, about 1.2) set in advance with respect to the taken-in fuel supply amount is calculated, and the calculated set air flow rate and the actual air volume sensor 33 detect it. It is preferable to adjust the amount of air supplied from the blower 3 via the inverter 35 based on the amount of difference from the amount of air blown.

By doing so, the distance between the gap A between the outer edge of the flame holding plate 10a and the inner peripheral wall of the throat body 5a and the distance B between the center opening 10b of the flame holding plate and the fuel injection nozzle 8 are adjusted in a narrowing direction. Due to the increase in air resistance due to the increase in air resistance, even if the blower 3 cannot blow air according to the set air volume and the actual air volume is less than the predetermined air ratio, the shortage of air volume can be compensated. The air volume of the blower 3 can be corrected sequentially, and problems such as combustion failure and misfire due to insufficient air volume can be prevented, and stable flame formation becomes possible.

Then, during the operation of the burner 1 having the above configuration, for example, when the burner combustion amount is increased, the internal static pressure of the burner main body 2 increases with the amount of air blown from the blower 3, but when the static pressure sensor 20 detects it, The static pressure / flame-retaining plate / fuel injection nozzle adjustment controller 21 connects the flame-retaining plate 10 and the fuel injection nozzle 8 at the tip of the rod member 6 via the stepping motor 17 of the advancing / retreating means 14, and the arrow X in FIG. Move forward (to the left in the figure) as shown by.

Since the inner diameter of the throat body 5a has a substantially tapered structure that gradually expands toward the front (leftward in the drawing), the flame holding plate outer edge 10a and the throat body are formed as the flame retaining plate 10 moves forward. The distance between the gap A and the inner peripheral wall of the portion 5a gradually widens, and at the same time, the static pressure inside the burner main body 2 decreases. Then, when the static pressure returns to a predetermined value (for example, about 300 mmAq), the flame holding plate 10 is stopped at that position.

At this time, as shown in FIG. 2, the front side of the flame holding plate 10 on which the burner flame is formed passes around the fuel injection nozzle 8 (the gap B between the fuel injection nozzle 8 and the flame holding plate center opening 10b). Then, along with the combustion air that escapes to the central opening 10b of the flame holding plate, the combustion air that passes through the gap A between the outer edge portion 10a of the flame holding plate and the inner peripheral wall of the throat body 5a is supplied, and stable flame formation is possible. It becomes.

On the other hand, when the burner combustion amount is reduced, the static pressure inside the burner main body 2 decreases with the amount of air blown from the blower 3, but when the static pressure sensor 20 detects it, the static pressure / flame holding plate / fuel injection is performed. The nozzle adjustment controller 21 connects the flame holding plate 10 at the tip of the rod member 6 and the fuel injection nozzle 8 via the stepping motor 17 of the advancing / retreating means 14 as the first-stage static pressure adjustment control, and the arrow Y in FIG. Retreat (to the right in the figure) as shown by.

Then, as the flame retaining plate 10 retracts, the distance between the gap A between the flame retaining plate outer edge portion 10a and the inner peripheral wall of the throat body portion 5a gradually narrows, and the internal static pressure of the burner body 2 rises at the same time. To go. Then, when the static pressure returns to a predetermined value, the flame holding plate 10 is stopped at that position. During this period, the gap B interval between the flame holding plate 10 and the fuel injection nozzle 8 is maintained at a constant interval by the urging force of the urging means 9.

Further, if the internal static pressure cannot be adjusted to the predetermined value even if the flame retaining plate 10 is completely retracted to the end of the throat 5 base, that is, even if the flame retaining plate 10 has no adjustment margin, the static pressure / retention is performed. The flame plate / fuel injection nozzle adjustment controller 21 extends the piston rod of the cylinder 23 of the fixing means 22 as shown by the arrow Z in FIG. 4 as the second stage static pressure adjustment control, and restrains the tip portion. The outer edge portion 10a of the flame holding plate is sandwiched between the pieces 24 to temporarily restrain and fix the advancing / retreating operation of the flame holding plate 10.

Then, in this state, the traveling direction of the fuel injection nozzle 8 at the tip of the rod member 6 is switched via the stepping motor 17 of the advancing / retreating means 14, and as shown by the arrow X in FIG. ) While resisting the urging force of the urging means 9, the flame retaining plate 10 in the fixed state is advanced so as to approach the central opening 10b.

At this time, when the flame holding plate 10 is completely retracted to the end of the throat 5, the gap A on the outer edge portion 10a of the flame holding plate, which is a part of the flow path of the combustion air, is substantially closed, and the flow of the combustion air The path is limited to the flow path that passes around the fuel injection nozzle 8 and exits to the flame holding plate center opening 10b, and in that state, the fuel injection nozzle 8 approaches the flame holding plate center opening 10b. By doing so, the limited flow path of the combustion air is further narrowed, and the static pressure in the burner main body 2 can be effectively increased. Then, when the internal static pressure returns to a predetermined value (for example, about 300 mmAq), the fuel injection nozzle 8 is stopped at that position.

In the above embodiment, the flame holding plate 10 and the fuel injection nozzle 8 are attached to one rod member 6, and the flame holding plate 10 and the fuel injection nozzle 8 are synchronized with each other as the rod member 6 moves forward and backward. However, the configuration is not limited to this. For example, a pair of rod members are arranged side by side so as to be able to advance and retreat along the longitudinal direction of the burner body 2, and one rod member is the same as described above. A fuel injection nozzle 8 is fixed to the tip of the hollow shape having a fuel supply pipe and a return pipe built therein, and a flame retaining plate 10 is fixed to the tip of the other rod member. It is also possible to adopt one individually provided with advancing / retreating means 14 for advancing / retreating the rod member on the base end side of the member.

In the case of the above configuration, when reducing the burner combustion amount, first, as the first stage static pressure adjustment control, the rod member to which the fuel injection nozzle 8 is fixed and the rod member to which the flame holding plate 10 is fixed are mutually attached. Adjust the internal static pressure of the burner body 2 to a predetermined value by narrowing the gap A between the outer edge of the flame holding plate 10a and the inner peripheral wall of the throat body 5a while synchronizing so as not to change the gap between the two. Primary adjustment). If the internal static pressure cannot be adjusted to the predetermined value even if the flame holding plate 10 is completely retracted to the end of the throat 5, the rod member on the flame holding plate 10 side is stopped as the second stage static pressure adjustment control. While keeping the flame holding plate 10 at the end of the throat 5, the rod member on the fuel injection nozzle 8 side is switched to move forward, and the flame holding plate 10 is moved forward with respect to the central opening 10b of the flame holding plate in the stopped state. The fuel injection nozzle 8 is brought close to each other, the gap B between the flame holding plate center opening 10b and the fuel injection nozzle 8 is narrowed, and the internal static pressure of the burner main body 2 is finely adjusted (secondary adjustment) to a predetermined value.

With such two-step static pressure control, in a burner with a high turndown ratio, even if the amount of combustion air is near the minimum combustion amount, which is extremely small compared to the maximum combustion amount, it is injected from the burner body 2. The injection flow velocity of the combustion air to be produced can be maintained at the same level as that at the time of high combustion amount, and the fuel oil and the combustion air can be satisfactorily burned without deteriorating the stirring mixture.

In the two-step static pressure control, for example, before the flame holding plate 10 is completely retracted to the base end of the throat 5, that is, a state in which a slight gap A between the outer edge of the flame holding plate 10a and the inner peripheral wall of the throat body 5a is left. Therefore, the fuel injection nozzle 6 may be brought close to the central opening 10b of the flame holding plate. In that case, the internal static pressure of the burner body 2 can be finely adjusted while securing a flow path of the combustion air on the outer edge portion 10a side of the flame holding plate to some extent, whereby, for example, the fuel oil and the combustion air are agitated and mixed. It can be expected to improve the sexuality and to take measures against redness of the throat 5.

The present invention can be widely used for pressure spray burners for liquid fuels.

1 ... Burner 2 ... Burner body 3 ... Blower 4 ... Blower duct 5 ... Throat 5a ... Throat body 6 ... Rod member 8 ... Fuel injection nozzle 9 ... Biasing means 10 ... Flame retaining plate 10a ... Flame retaining plate outer edge 10b ... Flame retaining plate center opening 12 ... Fuel supply piping 13 ... Fuel return piping 14 ... Advancing / retreating means 20 ... Static pressure sensor 21 ... Static pressure / flame retaining plate / fuel injection nozzle adjustment controller 22 ... Fixing means 27 ... Flow sensor 33 ... Air volume sensor 35 ... Inverter (air volume adjusting means)
36 ... Fuel / air volume adjustment controller

Claims (3)

Connect the small diameter portion side of the throat having a throat body of截head conical hollow in the front end opening portion of the burner body of a single cylinder structure, the flame holding plate annular inner diameter and the same diameter of the burner body,-holding It is equipped with a fuel injection nozzle located behind the flame plate, and the flame holding plate allows the flame holding plate to move forward and backward in the throat body along the longitudinal direction of the burner body, while the fuel injection nozzle is located at the center opening of the flame holding plate. On the other hand, the burner body is provided with a static pressure sensor for detecting the internal static pressure, and the flame holding plate and the fuel injection nozzle are provided based on the static pressure value detected by the static pressure sensor. The first-stage static pressure adjustment control for adjusting the gap between the outer edge of the flame holding plate and the inner peripheral wall of the throat body by advancing and retreating while synchronizing, and the flame holding plate fixed at the base end of the throat. The static pressure inside the burner body is controlled by the two-stage static pressure control, which consists of the second-stage static pressure adjustment control that finely adjusts the gap between the center opening of the flame holding plate and the fuel injection nozzle by advancing and retreating only the fuel injection nozzle. A burner characterized by forming a flame while maintaining a predetermined value. As the set static pressure value inside the burner body, a static pressure value at an arbitrary combustion amount that can maintain stable flame formation is set, and the static pressure value detected by the static pressure sensor is lower than the set static pressure value. The burner according to claim 1, wherein the two-step static pressure control is performed only when the burner is used. The flow rate sensor for detecting the flow rate of the fuel supply pipe that supplies fuel to the fuel injection nozzle, the air volume sensor for detecting the air flow rate of the blower that supplies combustion air to the burner body, and the air flow rate of the blower are adjusted. It is equipped with an air flow rate adjusting means, and is based on the difference value between the set air volume corresponding to a predetermined air ratio with respect to the fuel supply amount detected by the flow rate sensor and the actual air volume detected by the air volume sensor. The burner according to claim 1 or 2, wherein the air flow rate of the blower is adjusted and controlled via the air flow rate adjusting means.

Images