US2747655A

US2747655A - Ignition burner for pulverized-fuel-burning furnace

Info

Publication number: US2747655A
Application number: US306147A
Authority: US
Inventors: Farnham Rex Couvelas
Original assignee: Individual
Current assignee: Individual
Priority date: 1951-08-27
Filing date: 1952-08-25
Publication date: 1956-05-29
Anticipated expiration: 1973-05-29

Description

May 29, 1956 R. c. FARNHAM IGNITION BURNER FOR PULVERIZEDFUEL-BURNING FURNACE Filed Aug. 25, 1952 3 Sheets-Sheet l mm mm W m mm Om mm mm May 29, 1956 c. FARNHAM IGNITION BURNER FOR PULVERIZED-FUEL-BURNING FURNACE 3 Sheets-Sheet 2 Filed Aug. 25, 1952 G m Z UWV May 29, 1956 R. c. FARNHAM 2,747,655

IGNITION BURNER FOR PULVERIZED-FUEL-BURNING FURNACE Filed Aug. 25, 1952 3 Sheets-Sheet 3 United States Patent Q l IGNITION BURNER FOR PULVERIZED-FUEL- BURNING FURNACE Rex Couvelas Farnham, Woodley, Reading, England Application August 25, 1952, Serial No. 306,147

Claims priority, application Great Britain August 27, 1951 9 Claims. (Cl. 158-1) The invention relates to burners whether for use as main burners or ignition burners, and is particularly applicable to ignition burners for pressure raising and pulverised fuel furnaces.

It is one of the main problems in furnaces of this kind using fuel ignition burners to safeguard the burner and the burner ignition means from disintegration, due to the intense heat evolved.

In an effort to solve this problem it has previously been proposed to mount the burner and ignition means so as to be horizontally slidable in the wall of the furnaces, whereby it is readily adapted to be withdrawn after ignition has taken place. Such constructions have not proved satisfactory in practice. A further disadvantage is that the oil may, due for example to non-ignition of the igniter, flow into the furnace without being ignited.

The invention has among its objects to avoid the disadvantages above referred to, and to provide a burner and ignition means which are so mounted as to preclude the possibility of their being damaged by the intense heat evolved when the furnace is ignited.

The invention has further among its objects to provide an ignition burner and associated parts which are of simple and robust construction, and efficient in operation.

According to the invention, the burner which in the position of use extends horizontally through an opening in the wall of the furnace is pivotally mounted so as to be adapted to swing outwardly, advantageously into a position beyond the vertical plane of the outer surface of the furnace wall, after ignition is completed.

The burner may be adapted to swing in a vertical plane or in a horizontal plane or in any plane intermediate these two planes.

According to the invention furthermore, means are provided operating in conjunction with the burner, which are effective to seal the opening or port in the wall of the furnace in which the burner is mounted both while the burner is in use and after withdrawal of the burner after ignition is effected. Such means may take the form of plates extending for example, mutually at right angles from a jointing position or at an inclination to the burner axis or at different radii to the burner axis, one of the plates extending horizontally beneath and parallel to the burner in the position of use and extending short of the burner tip at the forward end to avoid disintegration by the heat of the furnace and serving also as a support for the burner, and the other (the longer) plate forming a closure for the substantially rectangular opening in the furnace wall when the burner is in operation.

The ends of the two closure plates may be provided with arcuate guide members extending from the forward edge of the burner to the free end of the longer plate forming the closure to the port in the position of use of the burner, and serving as a cam in the pivotal with-' drawal of the burner after ignition has been completed, to bear against a spring pressed member pivoted at the upper edge of the port or opening in thewall ofthe furnace which member is adapted to swing downwardly in the completely withdrawn position of the burner to complete the closure in cooperation with the shorter of the closure plates secured to and extending beneath the burner, and overlapping the edge of the shorter closure member to ensure an effective seal.

The burner operating means may comprise pistons movable in cylinders which are pivotally mounted at one end of a stationary base, the free end of the piston rod being pivotally connected to the rear end of the burner. The piston may be operated hydraulically or by air pressure and may be controlled electrically, by hand or automatically to move the burners into and out of the operative and inoperative positions.

According to the invention furthermore, the ignition means for the burner, advantageously electrically operated and extending adjacent and parallel to the burner, is mounted on the pivotal spindle of the burner and is adapted to be moved into and out of the operative position by a piston moving in a cylinder with, and in the manner of, the burner.

According to the invention furthermore, the igniting: means may be provided with sealing means in the form. of closure plates positioned to extend mutually at right: angles of the same kind as, and operating in the same way, as the burner.

According to the invention moreover, a photoelectric: cell or the equivalent may be mounted between the guide rails connecting the ends of the closure plates and directed in such manner at an angle to the direction of flow of the burner flame and out of the range of influence of the pulverised fuel flame, as to be adapted automatically to cut-off the supply of oil to the burner if the ignition means for any reasonfor example, a short circuit proves inoperative.

According to the invention furthermore, an automatically operated purging device or blower may be mounted on the inner lower peripheral surface of the port or opening in the furnace wall, which is brought into operation as the burner swings into its operative position of use, and serves to purge or clear the lower ledge of the port or opening of fuel, dust or other solid matter which may have deposited thereon, and which might operate to block or prevent the downward movement of the burner into the operative position.

According to the invention furthermore, automatically operated blower means and/or wiping means may be provided mounted in a convenient position to ensure that the transparent covering of the photo-electric cell is clear of dirt or dust and/or oil and thus retains its accuracy in its control of the fuel how to the burner in the event of damage to the igniter.

According to the invention furthermore, the burner may be provided with a flexible air connection or may be provided with a metal-to-metal joint with packing interposed.

The invention is diagrammatically illustrated by way of example in the accompanying drawings in which:

Figure 1 is a side elevation, partly in section,

Figure 2 is a corresponding front elevation, and,

Figure 3 is a side elevation of a modified construction.

The furnace to which the burners according to the invention may be applied is a furnace of rectangular section burning a pulverised fuel and having two or more fuel nozzles disposed, for example, at diagonally opposite positions at the corners of the furnace, and extending horizontally at a convenient height in the furnace in what is known as the ignition zone. Advantageously at midpositions between the pulverised fuel burners are mounted oil fuel ignition burners formed as cylindrical members and adapted in the position of use to project horizontally Patented May 29, .195

into the furnace, advantageously in the plane of the pulverised fuel nozzles.

Referring to the drawings, the oil is fed through an atomising nozzle 1 of known type which is mounted centrally in a surrounding cylinder 2 through which air is passed under pressure of, for example, 2-15 inches water gauge. Means 3, comprising radial vanes, set at a determined angle in the mouth of the annulus impart a swirling motion to the air in its passage out of the nozzle. Mounted above the cylinder 2 is a casing 4 carrying an igniter 5 provided with an igniter element 6.

The oil pipe, the air feed pipe and the igniter element are mounted as a single unit which is mounted on a supporting bracket 9 in bearings 10 on a transverse rotatable shaft 11. This the burner unit is adapted to be pivoted from the operative position shown in Figure l, to an inoperative position in which it is disposed vertically and completely outside the furnace wall 12. Air is supplied through a fixed duct to a horizontal inlet 1.6 which is rotatable on a horizontally extending portion 17 of the fixed vertical duct 15 a seal 18 being provided between the fixed and rotatable parts.

The supply of air to operate the drive cylinder is electrically controlled from a control panel, located at any convenient position. The supply of oil is under the control of the two

valves

27 and 28 which are mechanically operated by the movements of the burner into and out of the operative positions.

The movement of the burner is effected through a drive cylinder 19 pivotally connected at one end at 20 to the furnace wall and at the other end at 21 to a bracket 22 secured on the cylinder 2. Operation of the drive is through an electric relay and limit switch 23.

The horizontal movement of the igniter element 6 which is substantially simultaneous with the movement of the operation of an electric relay, withdrawn after a determined period, not greater than a few seconds.

The supply of oil to the nozzle is through filter 25, pipe 26,

control valves

27 and 28, the valve 28 operating as a secondary cut-off valve in case of failure of the valve 27. The piping 29 leading to the rear end of the t burner is flexible.

A sealing door or plate 31 is provided to extend transversely of the burner in the operative position of use, being formed of rectangular section, so as completely to cover the opening in the furnace wall.

An electronic viewer 30 is mounted to project through the sealing door 31 which obturates the opening in the furnace wall when the burner is in the operative position. The viewer 30 operates to draw the burner into the inoperative position in case of failure of ignition. The viewer is set to operate through an electric relay after a time lag of a few seconds, such time lag being greater than the period for lighting and withdrawal of the igniter.

A wiper device comprising linkage 32 is operated by

stops

33 and 33a provided on the igniter on the withdrawal and insertion of the igniter to cause a wiping movement across the face of the viewer 30 of an asbestos cloth 34.

A rod 35 is fixed at the rear 36 so that in the withdrawal movement of the igniter element it engages a catch 37 on a pivoted door 38 to close the end of the igniter casing, to prevent damage by burning to the igniter element.

The movement of the burner into and out of the operative position is guided by means of top guide rails 39 and bottom guide rails 40. Top and

bottom sealing plates

41, 42 provided on the undersurface respectively with

fins

43, 44 bear respectively on the top and bottom guide rails, so that when the burner is withdrawn, and the door or plate 31 no longer obturates the opening in the furnace wall, the sealing plate 41 pivots inwardly to meet the plate 42 carried on the burner casing, the end of the plate 41 engaging in a catch 45 provided on the underface of the plate 4-2 thus sealing the opening in the wall of the furnace on the withdrawal of the burner.

Air under pressure is bled off from the main duct to the burner casing 2 to cool the igniter housing 4: the top guide rails 39 are also cooled, being made hollow for the purpose, and if desired air is also bled off to cool the outer surface of the plate or door 31.

The electrical part of the apparatus is of known type, and its construction forms no part of the invention: it includes relays, a transformer mounted on a panel 46 at the side of the burner. The transformer is adapted to provide a voltage of about 10,000 volts for striking the arc of the igniter element. A guard 47 completely covers the front of the apparatus.

In operation, the pressure of a button energizes a relay, causes operation of the drive cylinder 19 to pivot the burner on the bearing, so that it comes to lie in the horizontal position of use illustrated in Figure l. Simultaneously, the movement of the burner operates through linkage 27a, 23a associated with the

valves

27, 28 to permit a flow of oil under pressure. Simultaneously the electric relay operates to drive fans to create a flow of air under pressure. Substantially simultaneously the electric relays operate to effect a forward movement of the igniter element and a striking of the are to ignite the atomised spray of oil. and air. The igniter element is withdrawn after a time lag suflicient to enable the are to strike and the door 38 is then closed.

Viewing observation holes 48 are provided in the door 31 which also enables the furnace to be lit by hand should the igniter element fail to light the burner.

A hand-operated switch 49 provides a master control for the oil, air and high tension electric supply, whereby the guard 47 cannot be withdrawn until the switch 49 is operated to cut-off the supply of oil, air and current.

Means comprising a hand-operated screw 50, are provided to adjust the fixed position of the oil pipe in the surrounding cylinder 2.

In the modified construction illustrated in Figure 3, the burner is mounted on a bracket 51 extending at right angles thereto, the bracket being pivotally mounted on a supporting bracket 52 secured on the front of the furnace wall. The construction follows essentially that illustrated with reference to Figures 1 and 2.

Modified linkage means 53 are provided to close the sealing plates on the withdrawal of the burner.

It will be understood that although the invention has been described with reference to an ignition burner, it is not limited in its application thereto, but may be applied generally in any cases where burners, whether main burners, auxiliary burners or ignition burners, can be used in furnaces, boilers and the like.

Iclaim:

1. In a pulverized fuel burning furnace including a furnace wall having an opening therein, a burner arrangement comprising: a support adapted to be mounted externally of said furnace wall and adjacent said opening, means for pivotally mounting the burner on said support whereby the burner may be pivotally moved to extend through said opening in the operative position, closure means carried by said burner for closing said furnace opening when the burner is pivoted to inoperative position and power means mounted between said furnace wall and said burner for withdrawing said closure means by pivoting the burner from the inoperative position to the operative position.

2. A burner as set forth in claim 1 wherein said burner carries an electronic viewer and electric relay means responsive to said viewer for pivoting the burner to the inoperative position on failure of the burner to ignite.

3. A burner as forth in claim 2 wherein said electronic viewer includes a wiper to clean the face of said viewer and means for mechanically operating said wiper.

4-. A burner as set forth in claim 1 wherein said cover plate includes air supply means for cooling said plate.

5. A burner set forth in claim 1 wherein said burner carries fuel and air supply means, a removable guard surrounding the rear of said burner and locking means for said guard operable to shut off the supply of fuel and air to said burner before said guard can be removed.

6. A burner as set forth in claim 1 wherein said burner carries fuel and air supply means, and means operable to shut off the supply of fuel and air to said burner when the burner is pivoted to the inoperative position.

7. A burner as set forth in claim 1 wherein said drive means comprise pistons operating in cylinders, said cylinders being pivotally connected to said support and said pistons being pivotally connected to said burner.

8. In a pulverized fuel burning furnace, including a furnace wall having an opening therein, a burner arrangement comprising: a support adapted to be mounted externally of said furnace wall and adjacent said opening, means for pivotally mounting the burner on said support whereby the burner may be pivotally moved to extend 'through said opening in the operative position, power means mounted between said furnace wall and said burner for pivoting the burner to and from the operative position, a major closure carried by said burner, a sealing plate pivoted to said furnace wall, and means coordinating movement of said closure and sealing plate when said burner is pivoted from operative position to inoperative 6 position to cause interengagement of said closure and seal to seal said opening.

9. In a pulverized fuel burning furnace, including a furnace Wall having an opening therein, a burner arrangement comprising: a support adapted to be mounted externally of said furnace wall and adjacent said opening, means for pivotally mounting the burner on said support whereby the burner may be pivotally moved to extend through said opening in the operative position, first and second closure means mounted on said burner for movement with said burner, said first closure means closing said opening when said burner is pivoted from inoperative position to operative position, and said second closure means closing said opening when said burner is pivoted from operative position to inoperative position, and means mounted between said furnace wall and said burner for pivoting said burner to operative and inoperative positions.

References Cited in the file of this patent UNITED STATES PATENTS 916,110 Creighton Mar. 23, 1909 1,001,863 Kirkwood Aug. 29, 1911 1,315,155 Pudney Sept. 2, 1919 1,371,490 Keller Mar. 15, 1921 1,719,608 Holden et al July 2, 1919 1,733,647 Coghlan Oct. 29, 1929 1,876,509 Stevens Sept. 2, 1932 2,361,117 Millett Oct. 24, 1944 FOREIGN PATENTS 408,031 Great Britain Apr. 5, 1934