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March 22, 1938. L. v. ANDREWS 2,111,908 COMBUSTION APPARATUS Filed Oct. 4, '1933 _ L. VANDREWs ‘ 2,111,908 Patented Mar. 22, 1938 PATENT OFFICE UNITED STATES 2411.908 COMBUSTION APPARATUS L. V.-Andrews, Worcester, Mass., assignor to Riley Stoker Corporation, Worcester, Mass‘, a corporation of Massachusetts Application October 4, 1933, Serial No. 692,162 (Cl. 110-—22) 5 Claims. _ Referring to the drawing illustrating one em bodiment of the invention, and in which like This invention relates to combustion appara tus, and more particularly to an apparatus suit reference numerals indicate like parts, able for burning pulverized fuel and oil either alone or simultaneously. 5 _ Que form of burner commonly utilized for burning pulverized fuel comprises a burner pipe arranged to discharge a jet of fuel and primary air through an openingin a furnace wall, the secondary air being introduced into the furnace 10 in a stream annular in cross-section and sur rounding the fuel jet. It has been proposed here tofore to mount an oil atomizing nozzle or “gun” inside of the fuel pipe in a ‘burner of this type, but various difficulties have been encountered 15 when burning oil alone ‘with such an arrange ment. Certain parts of the burner become over heated and hence require frequent replacement, and neither the capacity nor the combustion effi ciency is so great as would ordinarily be expected 20 from a burner designed for burning oil and hav ing no provision for the burning of pulverized fuel. - It is accordingly one object of the invention to overcome these difficulties and to provide an 25 apparatus which will burn pulverized fuel and oil, either alone or simultaneously, with high effi ciency and at high combustion rates when desired. . Fig. 1 is an elevation of combustion apparatus for burning pulverized fuel or oil under forced 6 draft, certain parts being shown in section; Fig. 2 is an enlarged view on the line 2-2 of Fig. 1; and ‘ Fig. 3 is a view similar to Fig. 1 but showing a natural draft installation. The embodiment illustrated in Fig. 1 comprises a vertical furnace wall Ill having an opening I l therein which is preferably circular and ?ares outwardly toward the rear or furnace side of the wall. A horizontal cylindrical burner pipe 15 I2 is mounted in front of the opening H and arranged to discharge pulverized fuel rearwardly and centrally through the opening. This pipe 12 is connected by means of a conduit M to a pul verizer l5 which may be of any suitable type, 20 one particularly satisfactory apparatus being dis closed in the patent to Riley et al. No. 1,759,134, At the rear or discharge end of the burner pipe I! I preferably mount a spreading device com prising a number of vanes H which extend‘radi- 25 ally across the path of the pulverized fuel stream. These vanes are arranged at an angle to the burner axis so that they de?ect the fuel and I It is a further object of the invention to pro throw it outwardly as it leaves the pipe l2. In vide a combination oil and pulverized fuel burner the preferred construction the vanes l1 are 30 30 and associated parts so constructed and arranged 7 mounted on the rear end of a small tube l8 that either fuel may be burned alone for long periods without damage to the burner. With these and other objects in view, as will be ‘apparent to those skilled in the art, the inven 35 tion resides in the combination of parts set forth in the speci?cation and covered by the claims appended hereto. . In accordance with my invention I provide a burner having a pipe for the delivery of pulver 40 ized fuel to a furnace, and. means to introduce secondary air around the outside of the fuel jet. An oil atomizing nozzle isrmounted within the pipe. The pipe is supplied with pulverized fuel through a conduit leading preferably from a suit 45 able pulverizer. Manually operable valve means is provided whereby air can be admitted to the conduit when burning oil alone. In case the burner is of the forced draft type, this air may be withdrawn’ from the forced draft duct. Other 50 wise, the air may be admitted under the influ ence of the natural draft of the furnace. In a forced draft installation, the valve means is preferably arranged to prevent blowing of the high pressure air in a reverse direction through 55 the pulverizer. ' i which is supported centrally within the pipe l2. ' Secondary air is introduced into the furnace through the opening Ii around the outside of [the fuel stream. For this purpose I provide walls 35 ' 20 forming an air chamber 2| located outside the wall l0 and communicating with the open ing ll. Air is supplied to the chamber 2i through a forced draft duct 22 which is connected to a suitable forced draft fan (not shown). Dampers 40 24 serve to control the ?ow of air from the duct 22 to the chamber 2]. The air entering the open ing I l is preferably given a. whirling motion about ' thev pipe I2 by means of vanes 25 mounted in the chamber 2|, these vanes being constructed and 45 arranged in the manner disclosed in the patent to Craig et al. No. 1,843,662. In order that oil may be burned when desired, an oil atomizing nozzle or “gun” 26 is mounted within the tube l8 with its rear or discharge end 50 adjacent the rear end of the burner pipe l2. Oil is supplied to the nozzle 26 through a pipe 21. When pulverized fuel alone is to be burned, the oil nozzle 26 may be removed if desired. .When burning oil alone with the apparatus as 55 2 2,111,908 so far described. there is a tendency for certain parts of the burner to overheat; Moreover, the oil burning capacity is limited, and the e?lciency of combustion is less than would normally be expected. These di?iculties have been overcome by providing means for introducing air into the furnace through the burner pipe l2. For this purpose I provide a passage 29 leading from the forced draft duct 22 to the conduit H, the 10 ?ow in this passage being controlled by a valve 39. A second valve 3| is provided in the conduit I 4 between the pulverizer l5 and the junction of the passage 29 with the conduit, this valve serving to prevent air from blowing back into 15 the pulverizer when the latter is shut down. The valves 60 and 3| are preferably‘ of the quarter turn plug type, one suitable construction being disclosed in my prior Patent No. 1,849,395. The operation of this embodiment will now When burning pulverized fuel, either alone or in com 20 be apparent from the above disclosure. bination with oil, valve 30 will be closed and valve 9| open. Pulverized fuel and primary air will ?ow from the pulverizer I6 through the con "25 duit I 4 to the burner pipe I2, and the stream as it issues from the pipe will be de?ected by the vanes l1 outwardly into the surrounding whirling stream of secondary air supplied from the cham ber 2| and duct 22. When oil alone is to be 30 burned, the pulverizer will be shut down, valve 3| will be closed, and valve 30 will be opened to allow air to ?ow from the duct 22 through the passage 29 to the burner pipe l2. This air will be de?ected by the vanes l1 and hence will be 35 whirling‘rapidly as it strikes the atomized oil immediately after the latter leaves the nozzle 26. The air is thus mixed with the oil almost instantly, and the combustion is extremely rapid and e?lcient. Moreover, the air ?owing through 40 the pipe l2 will cool this pipe and also the tube l8 and the vanes l'l, thus protecting these parts from overheating and ensuring a long ‘life of service. In Fig. 3 I have shown apparatus similar to that 45 already described, but arranged for use in an in stallation having natural or induced draft. This embodiment comprises a furnace wall 96 hav ing an opening 26 therein, and a burner pipe 31 in front of the opening to discharge pulverized 50 fuel therethrough. The pipe 31 is connected by means of a conduit 39 to a pulverizer“. De ?ecting vanes 42 are mounted at the rear of the pipe 31, these vanes being mounted on a tube 43 combustion of the oil. The secondary air is drawn inwardly through the opening 36 by the furnace draft. It will be apparent that the air can be in troduced into the pipe 31 in the manner dis closed in Fig. 3 even though the secondary air be supplied under pressure, but in such cases I prefer to utilize the construction shown in Fig. 1. Having thus described my invention, what I claim as new and desire to secure by Letters Pat ent is: ‘ 10 1. Combustion apparatus comprising a burner pipe adapted to discharge a jet of pulverized fuel and primary air, means .to supply secondary air around the outside of the fuel jet, means adjacent 15 the discharge end of the pipe to de?ect the issu ing fuel outwardly into the secondary air, a fuel pulverizer arranged to supply the pulverized fuel and primary air, a conduit connecting the pul verizer with the burner pipe, an oil atomizing 20 nozzle mounted within the burner pipe, a passage to supply air to the conduit at a point between the pulverizer and the burner pipe, and a valve to control the flow in the passage. 2. Combustion apparatus comprising a burner pipe adapted todischarge a jet of pulverized fuel and primary air, means to supply secondary air around the outside of the fuel jet, vanes adja cent the discharge end of the pipe and extending across the path of the fuel, said vanes being ar 30 ranged at an angle to the burner pipe axis so that they de?ect the fuel outwardly into the secondary air, a fuel pulverizer arranged to sup-v ply the pulverized fuel and primary air, a conduit connecting the pulverizer with the burner pipe, an oil atomizing nozzle mounted within the burn er pipe with its discharge end adjacent to said vanes, a passage to supply air to the conduit‘ at a point between the pulverizer and the burner pipe, and a valve to control the flow in the pas 40 sage. 3. Combustion apparatus comprising a burner pipe adapted to discharge a jet of pulverized fuel and primary air, means to' supply secondary air around the outside of the fuel jet, a tube mount ed within the burner pipe, vanes mounted on the tube adjacent ‘the discharge end of the pipe and extending radially across the path of the fuel, said vanes being arranged at an angle to the burner‘ axis so that they de?ect the fuel out 50 wardly into the secondary air, a fuel pulverizer arranged to supply the pulverized fuel and pri mary air, a conduit connecting the pulverizer with the burner pipe, an oil atomizing nozzle mounted within the tube with its discharge end 55 adjacent to said vanes, a passage to supply air to the conduit at a point between the pulverizer and the burner pipe, and a valve to control the ?ow in the passage. supported centrally within the pipe. An oil atomizing nozzle 44 is mounted within the tube 43, and an oil supply pipe 45 is connected to the nozzle. Vanes 41 are arranged around the out side of the wall opening 36 to whirl the sec ondary air which enters the opening under the in?uence of the furnace draft or suction. 4. Combustion apparatus comprising a burner 60 In order to admit air to the pipe 21 when burn ing oil alone, I provide a passage 49 which es— pipe adapted to discharge a jet of pulverized fuel tablishes communication between the conduit 39 and primary air, means including a forced draft and the atmosphere. The ?ow in this passage is duct- to supply secondary air around the outside of the fuel jet, means adjacent the discharge 65 controlled by a valve 50 similar to the valves end of the pipe to de?ect the issuing fuel out 65 30 and 3|. wardly into the secondary air, a fuel pulveriz~ The operation of this embodiment is similar to that of the Fig. 1 arrangement. When burning er arranged to supply the pulverized fuel and pulverized fuel either alone or‘ in combination primary air, a conduit connecting the pulverizer 70 with oil, valve 50 will be closed. when burning with the burner pipe, an oil atcmizing nozzle oil alone, the pulverizer will be shut down and mounted within the burner pipe, a passage con valve 50 will be opened, thus allowing the furnace necting the forced draft duct with the conduit draft to draw air inwardly through the passage at a point between the pulverizer and the burner pipe, and a valve to control the ?ow in the 49 and pipe 31. This air will cool the burner passage. _ 75 parts and aid in obtaining rapid and efficient 5. Combustion apparatus comprising a burner 3 . 2,111,908 pipe adapted to discharge a jet of pulverized fuel and primary air, means to supply secondary air around the outside of the fuel Jet, means adja cent the discharge end of the pipe to de?ect the issuing fuel outwardly into the secondary air, a fuel pulverizer arranged to supply the pulver -.ized fuel and primary air, a conduit connecting the pulverizer with the burner pipe, an oil atom-‘ izing nozzle mounted within the burner pipe, and valve controlled means to admit air directly from the atmosphere into said conduit ‘at a point be tween the pulverizer and the burner pipe. L. v. ANDREWS.