Патент USA US2108873код для вставки
Feb. 22, 1938. ' L, R, TEEPLE 2,108,873 PNEUMATIC CONTROL FOR AIR SUPPLIED TO A STOKER Filed July 17, 1934 2 Sheets-Sheet l fIIIIIIIIIIIIII‘III'I'I _$ 411 59 //\/4/5/\/ 777R L.. Q. TEEPLE' z )4 'TTUFQNE / Feb. 22, 1938. 2,108,873 L. R. TEEPLE PNEUMATIC CONTROL FOR AIR SUPPLIED TO A STOKER Filed July 17, 1934 2 Sheets-Sheet 2 Il/1 734 v.‘ \Y s. I E $9 3 //\/z/E/v7-UR 57/ L Q TEEPLE )WTURNE >7‘ Patented Feb. 22, 1938 2,108,873 UNITED STATES PATENT. OFFICE 2,108,873 PNEUMATIC CONTROL FOR- AIR SUPPLIED . . . TO A STOKER . Lawrence R. 'Teeple, Portland, Oreg. Application July 17, 1934; Serial No. ‘735,617 '1 Claims. This invention relates generally to underfeed ' ' ' ' . ~. stokers, and particularly to a means for auto matically controlling the amountoi air supplied the form of a set screw 26. to the combustion. the compressor by the laterally extending pipe ‘ the combustion zone of a furnace. The second object isto provide a control means 10 to be efficient in its operation, devoid of compli cations and at the same time capable of provid ing any desired amount of lag between the com mencement of fuel delivery and that of air de livery. " - These, and other objects, will become more ap parent from the specification following as illus trated in the accompanying drawings, in which Fig. 1 is a perspective view of an underfeed stoker equipped with my device. 20 Fig. 2 is a section taken along the line 2-2 in Fig. 1 showing the pilot damper partly open. Fig. 3 is a section taken along the line 3--3 in Fig. 1 showing the butter?y damper partly open. 2;, 110—69) holds the roller 24 against the eccentric 22 and an adjustment is provided forthe spring 25 in The main object of this invention is the pro vision of an exceedingly simple and efficient form of control for the air delivered by.the stoker to 15 (01. . . Fig. 4 is a somewhat diagrammatic view show ing the relation of the parts in detail with the distance between the elements greatly reduced; Fig. 5 illustrates the internal structure of the air valve mechanism showing a position which 3.3 the parts. can assume under conditions different than‘ those which are illlustrated in Fig. 4. Similar numbers refer to similar parts through out the several views. " . ’ , Referring in detail to the drawings, there is 35 shown an underfeed stoker including the fuel hopper ill, the fuel feeding tube II and retort l2, to .which fuel is delivered from the hopper I!) Air is admitted to 21 which communicates with an air ?lter 28. 5 ‘The discharge end of the cylinder 20 is closed by a bushing 29 which forms a- head therefor. . Within the bushing 29 is disposed a ball check 30 which closes on the intake stroke of the com pressor and forces the incoming air to be drawn 10 through the ?lter 28. The compressed air is d‘scharged through a pipe 3| into ‘an oil ?lter 32 which may be of' any suitable type,’ pref erably a simple container in which is disposed a.fabric covered cage through which the‘ air 15 passes for the ‘purpose of removing oil there-. from, from which it passes through a throttle valve 33 provided with an adjusting screw 34. The compressed air is ‘then carried to the T ?tting 35, one opening of which communicates 20 ‘with the ‘bel1ows'36 which is supported by. the bracket The bellows 31 within 36 actuates the casing a rack 38. 38 which meshes , with a pinion '40 secured on the shaft 4| of a butter?y damper i9 which can substantially close 25 ' the air duct l 5 when normal thereto. The operation of ‘this portion of the device is as follows: When the stoker motor I3 is op erated, air will flow through the ?tting 35 into the bellows. 36, causing it to open the butterfly 30 damper l9 and to remain open unless otherwise effected, as will be explained later. It is desirable to provide a spring 42. within the casing 43 for returning the rack 39 to the position shown in Fig. 4. ’ 35 Turning now to the pilot damper I8 it will be seen that same is: secured .to the shaft 44 on which is secured a slotted indicator plate 45 from through the tube II by means of a motor [3 which operates a screw (not shown); within the “ which projects a pointer 46 which is disposed ' 40 tube H. The motor l3 also operates a fan with in the casing 14 and which delivers air through the air duct i5 to the tuyere base i6 which sup ports the retort l2. - _ Referring more particularly to myinvention 45 same will be seen to consist of an air compressor unit [1 which is also driven from the motor l3, ' the pilot damper l8 and the butter?y damper IS. The air compressor l'l may of‘ course be of any desired type, ‘but for the purpose of illustration 50 ‘there, is shown a cylinder 20 within which opere ates a piston 2|. ' ' The piston 2l- is operated/by an eccentric 22v whichis supported by the compressor block 23. The eccentricv 22v acts'directly against a roller 24 _55 which is carried'by-the' piston~2l. The spring 25 alongside of the graduated 'cam 41, to which-‘it 40 is adjustably secured by means of the clamping screw‘48. The end 49 of the cam 41 constitutes a drop off or a low point, the purpose of which will be explained presently. The members 45 and 41 are mounted within a 45} casing 50 which supports a pivot 5! on which are \pivotally mounted the spring-urged arm 52, one end of which rides against the cam 41 and the other end of which is acted upon- by a spring 53 which re-acts against a second arm 54 which en- 50 gages a grooved collar 55 on the stem 55 which carries an air valve disk 57. The disk 51 seats over the outlet _58 of an air line 59 which con-I nects° with the side outlet of the T ?tting 35. The air line 59 is provided with a valve ‘60 hav- 55 2 2,108,873 lighter particles to be blown out of the retort [2 ing a relief opening Bl which is adjustably con before they could be protected by the incoming trolled by means of the set screw 62. It is neces ‘ sary to provide an outlet opening 63 by means of green fuel. It is for this reason that it is desirable to post which air can escape from the outlet '58 when pone the ?rst delivery of air until after the coal the disk 51 is withdrawn therefrom. feeding operation is well under way. The operation of the device is as follows: As The amount of lag can be controlled by the suming that the stoker motor [3 is started in response to any of the usual controls, the pilot adjustment of the screw 34 which does not effect the pressure within the bellows 38, but the rate of damper I8 having been at rest and the butter 10 air ?ow thereto. 10 ?y damper l9 being closed (as shown in Fig. 4) I claim: . as the compressor I1 is operated vand pressure 1. A pneumatic control for air supply to a builds up in_the ?tting 35 the bellows 36 be stoker consisting of an air duct having a pilot comes distended, moving the rack 38 and open ing the butter?y damper l8, and the pilot damp-V damper mounted therein whose position is re sponsive to the ?ow of air through said duct, a 15 er I8 is raised by the air ?owing past the butter control damper within said duct for controlling fly damper. This, however, does not happen in stantaneously, there being an appreciable amount the ?ow of air therethrough, a pneumatic ace of time between the moment the stoker starts tuator ‘for said control damper, an air supply feeding coal and the moment it starts feeding . ' controlled by the operation of said stoker for air, and this time can be varied, as will be ex operating said damper actuator, and. a cam op plained. - erated valve actuated by said pilot damper forv As the pilot damper l8 continues to rise, un 3 der the increasing ?ow of air permitted by the gradually opening butter?y damper I8, the cam 25 41 is carried with it-—that is, the end 49, whose position can be regulated by the screw 48, de sc'ends to a point which will permit the end of the arm 52 to move, under the in?uence of the spring 52—A, and, through the arm 54, open 20 controlling the pressure of air in said damper actuator. 2. The device described in claim 1, including means for relieving the air pressure from the 25 damper actuator when the pilot damper is at a position of rest. - _ ‘ 3. ‘A device of the class described, the combi nation of a fan, a motor for driving said fan, an air duct conveying air delivered by said fan, a 30 pilot'damper within said duct actuated by air passing therethrough, an adjustable cam actu ated by said pilot damper, an air valve operated by said cam, a control damper mounted in said duct for controlling the flow of air therethrough, 35 direction, under the in?uence of the spring 42, a rack and pinion for operating said control damper, an air operated actuator for said rack until the butter?y [9 reduces the air ?ow sum cientlytov bring about a sufficient drop of the ' controlled by said air valve, an air'compressor damper I8, which will cause the cam 41 to again operated by said motor for delivering air under pressure to said actuator, said air valve con 40 40 close the outlet 58. *It can be seen from the foregoing that there stituting a means ‘for relieving the pressure from is, produced by this arrangement a balanced con said actuator when said .pilot damper is raised ,dition—that is, the attendant merely sets the above a predetermined position by an excessive '30 the outlet 58. - ' . While the compressor I1 is sui?ciently large to overcome the leak at the outlet ii to the extent of operating the bellows 36, it is not able to do so when the outlet 58 ‘is open, as stated, causing the butter?y damper l8 to be moved in a closing indicator pointer 46 at the desired mark on the 45 graduated cam 41, which represents a predeter mined air ?ow, and this ?ow is maintained with in very close limits, due to the fact that when the ?ow exceeds,a predetermined maximum the outlet 58 will be opened and the damper l9 will 50 be moved toward a closed position, and when the ?ow falls below a predetermined minimum the' outlet 58 will be closed, causing the damper iii to be moved toward an opening position. It might seem that this would bring about a 55 rapid and continuous adjustment of the setting ?ow of air through said duct. , '4. The devicedescribed in. claim '3, together with a means for continuously relieving the pres sure from said actuator at a rate intermediate the rate of delivery by said compressor and the , rate of flow through said pilot damper-actuated, ,, air valve. 4 _, v 5. The device described in claim 1, together with means for regulating the amount of air which can be delivered by said compressor to said damper actuator. ' 6. A pneumatic control for air supplied to 55 of the butter?y damper, but such is not the case ‘in actual practice since the action is by no means stokers comprising an air duct having a butter- ’ instantaneous, the adjustments being slow and ?owing through said duct, a pilot damper which positive.‘ is free to swing in said duct under the in?uence ~ ' ‘ ?y damper for regulating the amount of _~air of air passing said. butter?y damper, a pneumatic 60 actuator for opening said butter?y damper durtioning of the bellows 38, is to gradually relieve , ing the operation of the stoker in connection with the pressure from the line 58 whenever the air which this device is used, spring means for clos ?ow through the duct l5 stops completely, due ing said butter?y damper in opposition to said pneumatic actuator, a source of compressed air 65 65 to a stoker shut-down and the damper I8 is in connected to said actuator by means of a pipe, the position of rest (as shown in Fig. 4). Unless this relief opening 6| was present, or an air valve communicating with‘said pipe be there‘ was’ not enough natural leakage in the tween said butter?y actuator and its source of air system, then the butter?y damper I! could re- . supply, means operated by said pilot damper for opening said air valve during the passage of an 70 70 main in a partially open position during the shut down so' that the next time the stoker ‘was excessive amount of air through said ductand operated air would immediately pass the butter?y closing said air valve during the passage of a. I9 and open the damper l8, producing an un quantity of air which is less than a predetermined desirable result, namely the delivery of air simul minimum, a, throttle valve betweenthe source~ taneously with the delivery of fuel, causing the of air supply and said actuator for retarding the 75 r 60 The purpose of the relief opening 8| which, as stated, is not large enough to prevent the func 2,108,878 ' 3 opening of said butter?y damper for a prede termined period after the commencement of air trol damper, means for delivering air to said ac tuator when said tan is operating, an air valve delivery'to said butter?y actuator. actuated by said pilot damper for releasing air through said actuator when the velocity of the ’ 7. In a. stoker the combination of an air supply duct having a fan for supplying combustion air thereto, a pilot damper in said duct responsive to the ?ow of air therethrough, a control. damper within said duct for controlling the'?ow of air therethrough, a pneumatic actuator for said con air exceeds a chosen value, and means for bleed ing air from said actuator to permit the control damper to close upon cessation of air ?ow to the actuator. ‘ LAWRENCE R. 'I'EEPIE.