US1709800A - Furnace using forced draft - Google Patents

Description

8 Sheets-Sheet 1 E. A. M ARTHUR FURNACE USING FORCED DRAFT Filed NOV. 11, 1925 f 1 Z A r J f INVENTOR April 16, 192.

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April 16, 1929. E, A, N's-ARTHUR 1,709,800

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* FURNACE USING FORCED DRAFT Filed Nov. 11, 1925 a Sheets-Sheet 5 INVENTOR Ap 16, .E. A. McAR'rHufi 1,709,800

. FURNACE USING FORCED DRAFT v gamed Nov. 11, 1925 a Sheets-Sheet. 6

INVENTOR T- %W 'I'rO NEY- m 9 E. A. MQARTHUR 1,7(j)9,800

FURNACE USING FORCED DRAFT Filed Nov. 11, 1925 a' g t v INVENTOR:

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April 16, 1929. I McARTHUR 1,709,800

FURNACE USING FORCED DRAFIf Fil 1925 a Sheets-Sheet 8 0 -"Hl'U-lir h HM W T WWW Patented Apr. 1 1929.

UNITED STATES PATIENT OFFICE.

ELMER A. MCARTHUR, OF FLINT, MICHIGAN.

summon USING roncn'n nnarn I Application filed November 11, 1925s Serial'NofGBAOG.

This invention relates to improvements in furnaces which are provided with force draft and stokers for supplying air and fuel thereto, the general object of the invention being to provide means for automatically controlling the amou ntof air and fuel supplied to the furnace which keeps the steam pressure constant and which also reduces thefconsumption of fuel to the minimum;

A further Object of the invention is to provide manually operated means for regulating the o eration of the inventiominsuch' a manner t iatithe steam pressure canbe'raised or lowered, as,desired. I

A further object of the invention is to provide means for co rct'mg the unburnt gases in the furnace and returning them to the fire box.

Another object of the invention is to make the furnace operate with but little attention 'on the part of the firemen, so that one fireman can take care of a battery of furnaces when necessary. I H

This invention also consists incertain other features of constructionand in the combination and arrangement-"of the several parts, to I be hereinafter fully described, illustrated in v in use.

the accompanyingdrawings and specifically. pointed out in the appendedclaims. I

In describing myinvention in detail-{retenence will be had to the accompanyingfdr'awings wherein like characters denote like or Figure 6 is a similar view,-but showing the wedge member and its operating mean'siri lowered position. v

Figure 7 1s a section on line 77 of Figure 5.

Figure 8 is an enlarged View, with parts in section, of the.,.stea'm actuated means for automatically controlling the air blast.

Figure 9 is a sectional view througlrthe Figure 4 is a section on line 4-4 of Fig- I rear part of a furnace, showing the gas collecting means.

collecting means. I I

Figure 11 is an enlarged View partly in section of the stoker and the operating parts associated therewith.

Figure 10 is a sectional view taken at right angles to Figure 9, and showing the gas" In these drawings, 1 "indicates the grate of the furnace upon which coal is pushed from the chute 2 by the stoker 3, the ram 4 of which is located in the horizontal part of the chluteand the pusher rod of which is shown at 4. The drawings show the Jones type of stoker, thoughit will be understood that any other type may be used. The air blast apparatus is shown at 5 and is arranged below is arranged under the grate aiid in which is located my valve or bafile for contrdlling the amount of air passing through the grate. It'w'ilLbe noted that the, inner end of the grate is lower than theouter end. This valve or baflle comp-rises a shaft 8 journaied in the chambei 'f and having secured thereto the disks 9, an upper wing and the lower wing 11.- .These wings are' -m'ovably connected with the shaft and the upper wing is adjustably connected with the disks by means of the .the floor 6 of the boiler room. This apparatus delivers the air into the chamber 7 which j slot and boltconnection shown generallyat t; 12, while the"low er wing is adjustably con f nected with the u'pper wing by means ot' thef I: two pairs of links 13, the links of each pair being connected together by the bolt and slot connections, shown enerally at14.' Thus the upper wing. can e adjusted relative to v the shaft and-its'disk and the lower wing can be adjusted relative to the upper wing. The

upperwing, when in its raised position, will 9 have its beveledend engage a plate whichis arranged under a number of thegrate bars of grate 1, the spaces between which are filled, as shown at 1. The upper wing is provided with anopening 10 which is adapted to be closed by a flap l6 adjustably connected tea.

fiap' 17 hinged to the: end of the lower wing 11 by means of the two pairs of links 18, the links .of each pair being adjustably connected together by the bolts and slots, shown generally lower wing and these springs are connected with the flap 16 by the connections 21 which include the turnbuckles 21, the springs tending to hold the valve 16 inopen position at r s are nnec ed with the These parts are so arranged that when in lowered position, the lower wing will cover the outlet of the blast apparatus so that when position, the device will cause most of the air to. pass through the inner portion of the grate, Where the bars are spaced farther .apart than are the bars of the rest of the grate. Thus the green fuel which has just been pushed on to the grate by the stoker is subjected to but littledraft, so that it will gradually coke and the gases from the same be consumed in the fire box, while the fuel on the inner or rear part of the grate which has been coked will be subjected to the major portion of the blast and thus be consumed with the minimum amount of waste. .If the blast is at its maximum, the pressure against the lower flap 17 will swing the same inwardly and upwardly and thus cause the flap 16 to close the opening 10' in the upper wing and thus reduce the amount of air reaching the fuel on the outer part of the grate.

In order to make the operation of the furnace practically automatic, I provide means for controlling the amount of the air entering chamber 7 to act on the bafiie or valve by means of the steam pressure in the boiler. Such means comprises a damper 5 in the air passage of the blast apparatus 5 which has a gear 22 on its stem which meshes with a gear-23, rocked on a shaft by the movement of a segmental ear 24 whichis connected with the gear 23 by the connections 25. Gear 24 meshes with a similar gear 26 which is provided with a stem 27 to which a weight 28 is adjustably connected. These parts are arranged on a frame 29 which may be located in a pit in the floor of the furnace room. A cylinder 30 is arranged in said pit and is connected with the frame and its piston 31 has its rod 32 provided with two rollers 33 which receive the stem 27 between them, so that the stem must movewith the piston. A steam cushion line 34 isconnected with the upper part of the cylinder and contains a valve 35 and a pipe line 36 connects the lower part of the cylinder with the boiler. A sliding valve casing 37 and a rotary valve casing 38 are arranged in the line 36. A valve 39 in casing 38 is operable by the lever 40 pivoted to a link 41 and connected to the arm 42 of the valve and said valve is provided with the passage 43 which is designed to register with either the upper port 44 on the lower port 44' in the inlet end of the casing 38 and the branch passage 43 which is adapted to connect the passage 43 with the exhaust 45 of the casing 38.

A'slide valve 46 is arranged in the casing 37 and has its single port 47 arranged to register with either the port 48 or the port 48' in said casing. This valve has a spring 49 on its stem which tends to hold the valve with its port in register with the port 48 and a rod 50 is pivotally connected with the other end of the stem in the valve. This rod has its other end pivotally connected to a forked member 51 which passes through a hole in an arm 52 on the gear 24, a coiled spring 53 being arranged on the member 51 between the arm 52 and a nut 54 on said member. The pin 55 which connects the rod 50 with the member 51 passes through a curved slot 26 in the gear 26 and said rod 50 is provided with a pair of notches 50. A slide 56 is arranged in a guideway 57 on frame 29 and carries a projection 58 which is adapted to engage either one of the notches 50. The slide carries a roller 59 which is pressed against a cam part 60 on gear 26 by a spring 61 engaging the upper end of the slide.

When the pressure of steam in the boiler is at its highest point, the action of the steam on the piston 31 will have moved the weighted stem 27 of gear 26 to its highest point, and this movement of the gear 26 will act on the gear 24 and this movement of the gear 24 will be communicated to the pinion 22 of the damper of the blast apparatus through the connections 25 and gear 23 to close the same, so that the draft will be reduced to a minimum. As soon as the pressure, falls, however, the weighted stem 27 will move downwardly under the action of gravity and also by the action of the cushion of steam in the upper part of the cylinder and in the pipe 84, acti ng on the piston 31 so that the, gears 26 and- 24 will move upwardly to open the damper to increase the draft and during this action the arm 52 will compress the spring 53 until it is stronger than the spring 49, so that said spring 53, acting on the rod 50, which has been released by the projection 58 being moved upwardly out of the notch through the engagement of the roller-59 by the cam 60, will move the rod 50 and the valve 46 to the left in F igure 8,-thus closing the port 48 and shutting off the supply of steam to the cylinder 30. This movement of :rod 50 is communicated to the lever 40 which is connected with the rod by the pin .and slot connection 62 so that the valve 39will be moved'until the branch 43 of its passage is in register with the exhaust 45 of the casing 38 and the inlet end of passage 43 is out of register with the inlet I der the movement of the parts, it will move rod 50 again and place the port 47 of valve 46 in register with the port 48' in casing 37 and this further movement willv also move valve 39 to close the exhaust and place the second notch 50 in said rod 50 and locked the parts against further movement. As the steam pressure in the boiler rises under the increased draft by the opening of the valve or damper in the blast apparatus, the )ressure of steam in cylinder 30 will gradua ly overcome the weight 28 and the steam cushion in pipe 34 and thus raise the stem 27 and cause the gears :24 and 26 to move downwardly and partially closethe damper. Under this action, the spring 53 will lose some of its tension and the projection 58 will move out of the inner notch 50 as the roller on the slide moves over the cam 60, so that the spring 49 will snap the valve and the rod 50 to their first posi' tion and place the port 47 in the valve in register with port 48 so that the steam will continue to pass to the cylinder 30, but through port 48 instead of port 48. The parts will be locked in this position by the downward movement of theslide and the engagement of the projection 58 in the outer notch 50. The movement of the rod 50, un der the action of the spring 49, will move the plug 39 to its first position, as shown in Figure 8. Thus the steam pressure in the boiler will remain constant and in order to place the pressure at any desired degree, we provide a hand lever 63 which is connected by link 64 with the handle 65 of the cushion regulating valve 35 in pipe 34. The handle is connected by a link 66 with the handle 67 of a valve 68 which regulates the size of the outlet port 45 of casing 38. By moving the handlever to the desired degree on a scale associated with the lever, the steam pressure in the boiler can be held at the desired pressure.

As before stated, the baffle device in chamher 7 will be raised or lowered according to the amount of pressure of the air coming from the air blast apparatus and this will also help to automatically control the steam pressure in the boiler and in addition, the movement of the bafile will act to adjust the damper in the chimney of the furnace through means of an arm 68 on shaft 8 which is connected with the damper by the connection 69, so that the movement of the shaft 8 will be communicatcd to the damper in the chimney and thus further control the draft.

The baflle device is also used to regulate the stroke of the stoker so as to control the amount of fuel fed upon the grate bars. Such means consist of a lever 70 pivoted to the floor 6 and having an adjustable forked part 71 which is engaged by a pin 72 on one of the disks 9, so that when the disk is moved to a certain extent, the pin engaging the valve stems to each other.

forked part will rock the lever 70 on its pivot, and this movement is communicated to a lever 73 by a turnbuckle rod 74 which is connected with a bell crank 75 on the lever 73 so that the lever 73 is not only moved but its latch 73 is also actuated by the movement of the lever 70. The latch 73 is adapt ed to engage a notch of a segmental rack 118 for maintaining the parts associated with the levers 73 in a predetermined position until said latch is released. An arm 76 is connected with the shaft to which the lever 73 is connected and this arm has a roller 77 on its free end which engages a plate 78 pivoted to the block 7 9 carried by the fixed rod 111, said block 79 having a slot 80 therein which receives a pin 81 on the depending arm 82 of the ram of the stoker. The plate 78 engages a wedge 83 which is slidably mounted in a slot 79" formed in the block 79. A pin 84 secured to the wedge and movable in a slot 80 of the block, guides the wedge in its movement. The parts are so arranged that as the plate 78 is forced upwardly by the arm 76, it will move the wedge upwardly and thus prevent the pin 81 on arm 82 reaching the outer end of the slot 80 and thus the stroke of the stoker is shortened and less coal is pushed upon the grate bars. The pin 81 not only guides the lower end of the arm 82, but in conjunction with the end of the slot 80 limits the movement of the arm.

I also provide means for reclaiming some of the roducts of combustion, such means comprising a chamber 84 arranged over a passage 85' which connects the chimney 86 with the major portion of the furnace and bafiles 87 are arranged in the bottom of the chamber and extend into the top of the passage so that the lighter particles of the gases passing through the passage 85 will be di rected into the chamber by these baffles. The passage of the gases into the chamber is controlled by the valves 88, all of which are manually controlled through-the, chain 89. the double lever 90 connected with one of the valve stems and to which the chain is connected and the links 91 which connect the A weighted gate 92 controls an air opening 93 in one end of the chamber and a chamber 94 having a fan 94 or other suction producing device is in communication-with the other end of the chamber 84 The flat valve 92 controls the amount of air passing into the conduit 84, and the opening of said valve depends upon the speed of rotation of the fan 94. Therefore the valve 92 controls the proper quantity of air to be supplied to the products of combustion for a complete burning of said products. A pipe line 95 connects the outlet of the chamber 9-1- with a pipe 96 which extends into thev combustion chamber of the furnace so that the reclaimed gases will be discharged into through the line 95 by the valve or baflie de vice in chamber 7. Such means consists of a gear 97 on the stem of a damper in said line 95 and which meshes with a gear 98, the

shaft of which is connected with an arm 99 to which a link 100 is adjustably connected, the other end of the link being adjustably connected with one of the disks 9 through means of, the slot and bolt connection 101.

A damper 97* is rigid with the shaft of gear 97 From the foregoing, it will be seen that the air blastdevice is controlled by the steam pressure in the boiler so that this device will be actuated to maintain a constant pressure in the boiler, the pressure desired being set through the hand lever 63. The valve or baifle device in chamber 7 also acts'in conjunction with the air device to automatically control the pressure through its draft con-v trolling properties, the damper in the chimney, the changing of the stroke of the stoker and its control over the damper in the reclaimed gas line. As before stated, the said device in chamber 7 also insures the proper combustion of the fuel through the control of the draft to the green or fresh fuel. The operation of this apparatus, when applied to a furnace, is practically automatic and needs but little attention on the part of the firemen, so that the one fireman can look after a greater number of furnaces provided with my invention than he could if the furnaces were not provided with the invention.

It is thought from the foregoing descrip-v tion that the advantages and novel features of my invention will be readily apparent.

I desire'it to be understood that- I may make changes in the construction and in the combination and arrangement of the several parts, provided that such changes fall within the scope of the appended claims. A block 7 9 is supported by a rod 111 which has one end secured to said block and the'other end carried by a wall 112 of the furnace. The push rod 4 mounted in the cylinder which formspart of the operating means of the stoker has a piston 110 mounted therein actuated by steam or compressed air for actuating the ram at at the bottom of the chute where the ram 4* slides over the same. The bottom of the chute 2 has an opening over which the ram .4 slides when moving the coal onto the grate 1 and through which is adapted to be moved the arm 82 which is connected with the ram 4 and which is adapted to be engaged by the wedge 83 for limiting the outward movement of the ram and tl1crcby controlling the stroke of said ram,

At the rear of the furnace achamber 120 is shown in which the water tubes 121 are extended and adjacent the passage 85. A wall ing means 89 for the baflles 87.

"What I claim is 1. In a furnace, a steam boiler, a grate, in

heating relation with the boiler, an air passage in communication with the grate, an air blast device in communication with the air passage, means for controlling the air blast in response to the steam pressure in the boiler, a baffle for controlling the draft to the green fuel on the grate of the furnace, and means actuated by the draft for mvoing the battle to controlling position. 1 I

2. In a furnace, a steam boiler, a grate in heating relation with the boiler, an air passage in communication with the grate, an air blast device in communication with the air passage, means for controlling the air blast in response to the steam pressure in the boiler, a battle for controlling the draft to the green fuel on the grate of the furnace, means actuated by the draft for moving the baffle to controlling position, a stoker having a reciprocating ram, and means actuated by the movement of the baflle for controlling the strokes of the ram. I

3. In a furnace, a steam boiler, a grate in heating relation with the boiler, an air passage in communication with the grate, an air blast device in communication with the air passage, means for controlling the air blast in response to the steam pressure in the boiler, a baflie for controlling the draft to the green fuel on the grate of the furnace, means actuated by. the draft for moving the battle to controlling position, manually operated means associated with the controlling means for the blast apparatus foradjustin'g the controlling means to hold the steam pressure at any desired degree.

1-. In a furnace, a steam boiler, a grate in heating relation with the boiler, an air passage in communication with the grate, an air blast device in communication with the air passage, means for controlling the air blast in response to the steam pressure in the boiler, a battle for controlling the draft to the green fuel on the grate of the furnace, means actuated by the draft for moving the baflie to controlling position, means for reclaiming the unconsumed gases passing from the furnace and introducing them at a point above the grate, and means for controlling the flow of such gases.

5. In a furnace, a steam boiler, a grate in heating relation-with the boiler, an air passage in communication with the grate, an air blast device in communication with the air passage, means for controlling the air blast, in response to the steam pressure in the boiler,

a bafiie for controlling the draft to the green fuel on the grate of the furnace, means actuated by the draft for moving the battle to controlling position, means for reclaiming the loo unconsumed gases passing from the furnace and introducing them at a point above the grate, means for controlling the flow of such gases, and means operatively connected with the battle for operating the controlling means for the gases.

6. In a furnace, a grate, an air blast apparatus, means leading from the air blast appa ratus to the grate, a swinging baflle for controlling the flow of air through the grate, said baflle comprising an upper wing and a lower wing ad justably connected together, the lower wing being positioned to be acted upon by the blast to move the battle,the upper wing having an opening therein, a. movable fia p for covering the opening, a movable flap on the lower wing, and means for adjustably connecting the two flaps together, the last mentioned flap being positioned to be acted on by the blast to move the first mentioned flap to closing position.

7. In a furnace, a grate, an air blast apparatus, means leading from the air blast apparatus to the grate, a swinging battle for controlling the flow of air through the grate, said baffle comprising an upper wing and a lower wing adjust-ably connected together, the lower wing being positioned to be acted upon by the blast to move the baflie, the uper wing having an opening therein, a movable flap for covering the opening, a movable flap on the lower wing, means for adj'ustably connecting the two flaps together, the last mentioned flap being positioned to be acted on by the blast to move the first mentioned flap to closing position, and spring means for holding the upper flap in open position.

8. In a furnace, a grate, an air blast device, an air passage placing the grate in communication with the air blast device, 'a ram adapted to be actuated for stoking the furnace and provided with a. depending arm, a swinging baflie for controlling the passage of air to the grate, and acted on by air from the air blast device for causing swinging of the battle, a lever rocked by the movementof the baflle, a second lever, means for moving the second lever by the movement of the first lever, an arm actuated by the second lever, a wedge member movable by the arm and engaging the depending arm of the ram for varying the reciprocating movement of said ram, a block slidably supporting the Wedge member and having a slot therein, and a pin on the arm which depends from the ram, said pin being received within the slot for guiding the arm in its movements.

9. In a furnace, a grate, a swinging battle for controlling the draft to the grate and comprising a shaft, a pair of discs on the shaft, upper and lower wings movably connected with the shaft, means for adjustably connecting the upper wing with the discs, means for adjustably connecting the lower wing with the upper wing, the lower wing being positioned to be acted upon by the blast to move the battle, said upper wing having an opening, a movable flap for closing said opening, a spring for holding said flap in open position, a second movable flap hinged to the lower wing, means for connecting the flaps together, the last mentioned flap being positioned to be acted on by the blast to move the first mentioned flap to closing position, and a cross piece on the grate adapted to be engaged by the upper wing for limiting the movement of said wing.

10. In a furnace, a grate, an air blast device, an ash pit for placing the air blast de vice in communication with the grate, a baffle swingably mounted in the ash pit and adapted to be moved to an operative upper position relative to the grate by the air from the air blast for causing the air to be forced through the inner end of the grate, said bafile when in a normal inoperative and lower position permitting the air topass to all parts of the grate.

11. In a furnace, a grate, an ash pit located below the grate, a swingably mounted battle in the ash pit, an air blast device, said pit placing the air blast device in communication with the rate, said bafile cont-rolling the direction o' the path of movement of the air from the air blast device to the grate and to various parts of the grate, said bafiie being provided with an opening to normally permit the passage of air therethrough, a hingedly mounted flap carried by the baffle for closing the opening and means carried by the baflie and adapted to be actuated by the air blast for closing said opening, said actuating means including a movable flap adjustably connected with the first-mentioned flap whereby actuation of this second-mentioned flap by the air blast causes closing movement of the first mentioned flap. In testimony whereof I affix my signature.

ELMER A. MoARTI-IUR.

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