US3415230A - Method for removing soot from boiler tubes and apparatus therefor - Google Patents

Description

Dec. 10, 1968 J REALE 3,415,230

METHOD FOR REMdVING SOOT FROM BOILER TUBES AND APPARATUS THEREFOR Filed March 25, 1967 3 Sheets-Sheet 1 DAM/ 5R SrEAM "-10 CONTWOL rAN/r ll. amma Z2 i may WM/ 1 I I I I I i .H'

[30 E D P R 30 32 E l/Vl/E/Vffli. i JOSEPH REALE J. REALE METHOD FOR REMOVING SOOT FROM BOILER Dec. 10, 1968 TUBES AND APPARATUS THEREFOR 3 Sheets-Sheet 2 Filed March 23, 1967 JOSEPH //VVA/70 REALE HIS Arron/5K5 Dec. 10, 1968 .1. REALE 3,415,230

METHOD FOR REMOVING SOOT FROM BOILER TUBES AND APPARATUS THEREFOR Filed March 25, 1967 5 Sheets-Sheet 5 "ZIL EAMPEE M/VA/TOA. JOS EPH REA L United States Patent 3,415,230 METHOD FOR REMOVING SOOT FROM BOILER TUBES AND APPARATUS THEREFOR Joseph Reale, 1425 S. Broad St., Philadelphia, Pa. 19147 Continuation-impart of application Ser. No. 606,302, Dec. 30, 1%6. This application Mar. 23, 1967, Ser. No. 625,464

22 Claims. (Cl. 122-679) ABSTRACT OF THE DISCLOSURE This invention relates to minimizing air pollution by reducing to a minimum the escape, into the atmosphere, of soot from a boiler during the removal of the soot from the boiler tubes when steam is sprayed at the boiler tubes to dislodge the soot. After the steam dislodges the soot,

it is carried by the steam into a tank, in which most of the steam is condensed. The tank is connected by a pipe to the smoke stack, and the tank is provided with cooling water for condensing the steam, the condensed steam, water and soot then flowing to a suitable drain.

This application is a continuation-in-part of my patent application Ser. No. 606,302 filed Dec. 30, 1966, now abandoned.

BACKGROUND OF THE INVENTION This invention is directed to the field of air pollution control which, with the passing of each day, is becoming of more and more concern in all urban areas.

The effects of air pollution are fairly well known, as it has been reported to kill and sicken people and to destroy property.

One source of air pollution in industrial areas, is the soot which is emitted from smoke stacks when boiler tubes are cleaned. As is known, for maximum boiler efficiency, the boiler tubes should be cleaned periodically, for instance once a day. One common device for doing this is a steam spray device which sprays steam into the boiler, at the tubes, to dislodge the soot. The steam and the thus dislodged soot has heretofore normally been permitted to escape up the smoke stack and into the atmosphere.

BRIEF SUMMARY OF THE INVENTION It is an object of my invention to provide a method and apparatus for the cleaning of soot from the boiler tubes while substantially preventing or minimizing the escape into the atmosphere of the dislodged soot.

In my preferred method, the smoke stack damper is closed and the steam is sprayed into the boiler to dislodge the soot from the tubes. This steam and the dislodged soot is substantially prevented from escaping up the smoke stack by the closed damper and instead flows into a tank where most of the steam is condensed and disposed of, by flowing together with the soot, into a drain.

The apparatus I provide to accomplish this method comprises a main pipe connected between the boiler and the smoke stack damper at one end and at the other end to a substantially closed tank. The tank is provided with water spray means to spray cooling water into the steam to condense it and then the condensed steam, soot, and water flow through into a drain.

The foregoing and other objects of my invention, the principles of the invention, and the best modes in which I have contemplated applying such principles will more fully appear from the following description and accompanying drawings in illustration thereof.

3,415,230 Patented Dec. 10, 1968 In the drawings,

FIG. 1 is a front elevation, but mostly diagrammatic view, illustrating a boiler, a smoke stack in part, a tank, connecting pipes, and a drain;

FIG. 2 is a cross-sectional side view of the tank illustrated in FIG. 1, but showing the pipes connected thereto and the water spray device in side elevation;

FIG. 3 is a top view of the tank taken along the line 3-3 in FIG. 2;

FIG. 4 is a cross-sectional front view of the tank illustrated in FIG. I, but showing the pipes connected thereto and the water spray device in front elevation;

FIG. 5 is a sectional view of a part of the top vent pipe showing the interior water spray pipe;

FIG. 6 is a partial view similar to the lower right hand portion of FIG. 2, but showing a modification wherein the lower part of the tank is connected directly in the drain; and

FIG. 7 is a front elevation, but mostly diagrammatic view, illustrating a boiler, a smoke stack in part, a tank, connecting pipes, and a drain, similar to FIG. 1, but showing my preferred embodiment.

DESCRIPTION Referring to the drawings, and in particular to FIG. 1, a boiler 10 is shown (diagrammatically) connected to a suitable smoke stack 12, the latter including a damper 14. Spaced from the boiler 10 is a closed tank 16 connected to the smoke stack 12 by a main pipe 18 which generally inclines upwardly to the smoke stack, as shown. The pipe 18 is connected at the left hand end to the smoke stack 12 between the damper 14 and the boiler 10 and on the right hand end is connected to the top of the tank 16 at the front, left portion thereof. As shown in FIGS. 1 and 4, the pipe 18 has a damper 20 near the top of the tank 16, to close communication between the pipe 18 and the tank 16, when desired.

The bottom of the tank 16 is provided with drain means 21 comprising two elbow-shaped pipes 22 connected to the tank 16 at the bottom of its front wall, the bottom pipes 22 emptying into an open-top pan 24 having three elbow-shaped pipes 26 extending through a cover 28 of a drain 30, the drain 30 having a deeper well 32 into which a sewer pipe 34 extends.

The top of the tank 16 is further vented by two pipes and 42 secured to the top (FIGS. 2 and 4) of the tank 16 and extending within the tank 16 as pipes 401: and 42a having a tortuous or U-shape, as shown. The pipes 40a and 42a have open ends 43 and 45, respectively, facing to the front, as shown in FIG. 2, and formed by terminal elbows 43a and 45a. The U-shape pipes 40a and 42b are placed adjacent the rear wall of the tank, FIG. 2, and the entry elbows 43a and 45a are placed adjacent the left hand and the right hand side walls, respectively, of the tank 16, i.e., the elbows are close to the nearest side wall. Thus, the entry elbows 43a and 45a are spaced from the outlet 20a (of the pipe 18a) within the tank 16 to afford the required time for condensing most of the steam within the tank 16 before it attempts to leave the tank, and for sufiiciently wetting the soot so that it will drop down and flow out of the bottom of the tank 16.

Extending through the top wall of the tank 16 is a pipe 44 for cooling water, the pipe 44 being connected by branch pipes 46 to three water heads 48 which spray water into the tank 16 to cool and condense most of the steam which enters the tank 16 through the pipe 18. While circular spray heads 48 have been illustrated, an array of stacked straight pipes have been found satisfactory, and other shaped pipes, with suitable holes through which water may be sprayed, could also be used.

The pipes 40 and 42 extend upwardly from the top wall of the tank 16, as shown, the pipe 40 making a right angle turn and being connected to the left end of a larger pipe 50, the pipe 42 extending straight upwardly and curving to the right, as shown, and being connected to a cylindrical horizontal portion of the pipe 50 near the left end thereof. The pipe 50 continues to the right, as shown, to an elbow 51 where it turns downwardly at approximately a 90 angle, and the lower, vertical end of the pipe 50 extends, through the cover 28, into the drain well 32. To the elbow 51 is connected a branch water pipe 54 which has a forward spray head 56 extending into the elbow 51 and down into the vertical part of the pipe 50, the spray head 56 having sufficient holes to provide a water spray of cooling water to condense substantially all of the steam which is vented through the pipes 40 and 42, if desired.

As shown, the main pipe 18 is connected to the tank 16 by a substantially vertical portion 18a and to the smoke stack 12 by a sloping portion 1812, these two pipe portions meeting to form an angular joint 60, as shown in FIG. 1. A steam pipe 62 is connected to the angular joint 60, the steam pipe 62 being connected to a steam injector (not shown) disposed within the joint 60 to create a partial vacuum and thereby assist the fiow of steam from the boiler and smoke stack 12 to the tank 16.

Mounted on the boiler 10 is a steam spray device 70 for spraying steam within the boiler 10 during cleaning of the boiler tubes (not shown) by dislodging the soot which accumulates on them during normal operation of the boiler. Steam is supplied to the steam spray device 70 by a steam pipe 72 having a valve 74 which is closed during normal operation of the boiler 10 and opened when the cleaning operation is to be performed. The steam spray device 70 is of a well known type having means (not illustrated) for manually rotating the steam spray within the boiler so as to better dislodge the soot from the tubes.

The front wall of the tank 16 is provided with an access opening which is normally closed by a door 74a having suitable handles 76, the door being bolted into place by suitable studs and nuts 78 and the tank 16 rests upon suitable feet 80.

When it is desired to clean the boiler tubes, the normally open smoke stack damper 14 is now closed, and the normally closed damper 20 in the pipe 18a is now opened to provide communication between the boiler 10 and the tank 16. The water valve 80 is opened to supply water to the spray head devices 48 and 56.

Steam is then supplied through the pipe 62 to the injector within the pipe joint 60 and the valve 74 is opened to supply steam to the steam spray device 70. (If the pipe 62 is connected to the pipe 72 between the valve 74 and the steam spray device 70, the same valve, i.e., valve 74, will then control the flow of steam to both the steam spray device 70 and the steam pipe 62, but this is not illustrated.)

As the steam flows from the steam spray device 70 into the boiler 10, it dislodges the soot from the boiler tubes. This steam and soot would normally flow up the smoke stack and out into the atmosphere. However, since the damper 14 is closed at this time, some pressure buildup takes place within the boiler and the part of the stack below the damper 14, and this steam, and the sOOt which it carries along, flows under this pressure into the pipe 18 and is assisted in flowing into the tank 16 by the suction created by the steam injector in the joint 60. Thus, the steam and the soot flows forcefully, under pressure, out of the pipe opening 20a into the front of the tank 16, i.e., the lower left hand corner in FIG. 3, and is directed vertically downwardly, FIG. 4, due to the vertical disposition of the pipe 18a, toward the bottom of the tank 16.

The U-shaped pipes 40a and 42a are located, adjacent opposite corners, at the rear of the tank 16, the top in FIG. 3, i.e., remote from the portion of the tank in which the steam and soot enter from the pipe 18a, so that the steam entering the tank 16 tends to first flow down and then up towards the open ends of the elbows 43a and 45a, the U-shaped pipes 40a and 42a and the elbows providing tortuous paths helping to mufile and expend the energy of the steam.

Between the U-shaped pipes 40a and 42a and the outlet 20a of the pipe 18b are placed the water spray devices 48, as shown in FIG. 2, the devices 48 being approximately centrally located near the top of the tank so as to tend to spray water on the steam as it first enters the tank 16, and as it is about to leave through the open ends of the elbows.

Most of the steam which enters the tank condenses and with the water sprayed through the spray devices 48 flows out near the bottom of the tank through the elbowshaped pipes 22, into the pan 24, and in doing so carries with it the soot that has been removed from the boiler tubes.

The water and soot in the pan 24 then flows through the elbow pipes 26 into the drain 30 and eventually into the sewer pipe 34.

The open top pan 24 is provided merely as a convenience to visually inspect the water as it flows out of the tank 16 so that one can see that the water is, in fact, carrying along with it the soot removed from the boiler tubes. As a practical matter, the lower portion of the tank 98 may be connected, as shown in the modification illustrated by FIG. 6, by suitable pipes 100 directly to the drain 102.

To remove any water that may accumulate in the U-shaped pipes 40a and 42a, holes are placed at the bottom of the U from which the accumulated water drains into the bottom of the tank 16.

If a sufficiently large cooling means is used to condense the steam entering the tank 16, the vents provided by the pipes 40 and 42 would probably not be required, but the provision of these pipes adds a safety feature preventing an excessive pressure increase within the tank 16.

Further, while U-shaped pipes 40a and 42a have been shown with terminal elbows 43a and 45a, it will be understood that the device would be operative if the U- shaped pipes 40a and 42a and the terminal elbows 43a and 45a were omitted, i.e., the pipes 40 and 42 could only be connected to openings in the top of the tank 16.

Also, to vent the sulphuric and other noxious gases that may be carried along by the steam, a vent pipe is connected at one end to the elbow 51 and at the other end to the smoke stack 12 above the damper 14, as illustrated in FIG. 1.

The water pipe 54 is of smaller diameter than the vent pipe 120 and extends into the vent pipe 120, as shown, and down into the elbow 51 and the vertical part of the pipe 50.

Preferably a damper is provided in the vent pipe 120, adjacent and above the water spray pipe 56, the damper 130 being open during cleaning of the boiler tubes and shut otherwise.

Thus, I have provided a tank 16 which retains the steam carrying soot and the sulphuric and other noxious gases for a long enough time period to permit the soot to be wetted sutficiently to flow to the bottom of the tank and out thereof with the cooling water and condensed steam. The flow of cooling water has to be adjusted properly relative to the flow of steam. If too much water flows into the tank 16, it tends to choke the system, in which event the steam carrying soot backs up, and tends to come out of the boiler openings, i.e., around the boiler doors and other leak spaces in the boiler, into the boiler room, which is, of course, objectionable. If too little water flows into the tank 16, the soot will not get wet enough and not enough steam will condense, resulting in soot laden steam being vented either into the atmosphere through pipe 120 or into the drain through pipe 50.

Another feature of my invention is that a certain amount of the sulphuric and other noxious gases become trapped in the cooling water and the condensed steam and the gases are carried thereby into the drain instead of being vented to the atmosphere.

While in the foregoing method I have stated that the smoke stack damper 14 is closed during removal of the soot, because it increases the flow to the tank 16 and reduces the air pollution to a minimum, and hence is preferable, some of the soot dislodging steam from the boiler would flow into the pipe 18 and the tank 16 even if the damper 14 were kept open assumini of course, that the damper 20 in the pipe 1 8 is open at such time.

However, if the damper 14 is kept open during the soot removal, the diameter of the pipe 62 should be increased and the flow of steam should be increased so as to increase the vacuum created by the injector at the joint 60 whereby the amount of steam carrying soot entering the pipe 18 will approach the amount which would enter it if the damper 14 were closed at such time.

Referring to FIG. 7, the preferred embodiment of my invention is illustrated. The apparatus shown in FIG. 7 is generally similar to that shown in connection with FIGS. 1 to 5 and includes a boiler 210 having a smoke staok 212 with a damper 214, the smoke stack 212 :being connected by a pipe 21-8 to a tank 216 the bottom of which is connected to a drain 230 by drain means 221.

The pipe 218 is provided with a damper 220 adjacent the top of the tank 216 and the joint 260 in the pipe 218 is provided with a steam injector (not shown) supplied by steam through a pipe 262, the flow of steam being controlled by a valve 263, to create a vacuum in the pipe 21 8.

Cooling water is supplied to the top of the tank 216 by a pipe 244 and the top of the tan-k 216 is vented by pipes 240 and 242 which are connected to the larger pipe 250, as shown.

The vent pipe 250 has generally horizontal and vertical portions, as shown, and a connecting elbow 251 therebetween. Secured to the connecting elbow 251 is a vent pipe 270 which communicates with the smoke stack, as shown, above the damper 214. The vent pipe 270 includes a damper 271 adjacent the elbow 251.

The vertical portion of the vent pipe 250 extends into the drain 230, as illustrated, and is provided with a damper 275 adjacent the portion of the pipe which enters the drain.

The boiler 2 is provided with a steam control device 269 which receives steam from the boiler through a pipe 276, the flow of steam being controlled by a valve 277.

The vent pipes 240 and 242 extend into the tank 216 with the parts within the tank having the configurations illustrated and described in connection with FIGS. 1 to 5.

The cooling water pipe 244 extends into the tank 216 and has spray devices as illustrated an described in connection with FIGS. 2 and 4.

In operation, when it is desired to remove the soot from the tubes of the boiler 210, the damper 214 is closed and the damper 220 is opened to place the tank 216 in communication with the smoke stack 212 down draft of the damper 214. The damper 275 is closed which closes the communicating passage between the tank 216 and the drain 230 provided by the pipe 250. The damper 271 is opened to place the smoke stack in communication with the pipe 250 at the elbow 251.

Water is then admitted to the tank 216 through the pipe 244 by opening the valve 280. The valve 263 is then opened and steam flows into the joint 260 and down into the tank 216. Also, the valve 277, is opened admitting steam into the steam control device 269 to dislodge the soot from the boiler tubes.

At such time, the steam from the steam control device 269 dislodges the soot from the boiler tubes (not illustrated) and due to the closed damper 214 some pressure buildup takes place within the boiler 212, aiding the flow of soot laden steam into the pipe 218 toward the tank 216. The partial vacuum created by the steam flowing through the pipe 262 and the injector at the joint 260 also aids the flow of the soot laden steam. The soot laden steam enters the tank 216 and most of it is condensed by the cooling water flowing through the pipe 244 into the tank 216 the condensed steam, water and soot dropping to the bottom of the tank and flowing through the drain means 221 into the drain 230 and out into the sewer pipe 290.

Any part of the steam which is not condensed, together with the sulphuric and other gases which are not trapped in the condensed steam or the cooling water, are vented upwardly through the pipes 240, 242, 250 and 270 to the atmosphere through the portion of the smoke stack above the damper 214, the closed damper 275 preventing the uncondensed steam and the sulphuric and other gases from entering the drain. The damper 275 is provided so as to vent the steam and gases to the atmosphere rather than having them enter the boiler room as tends to happen when they are flowing to the drain, because of the tendency of the gases to escape into the boiler room at the loose connection between the pipe 250 and the cover of the drain 230. Thus, it is seen that the pipe 250 could be terminated and closed immediately downstream of its connection to the vent pipe 270, rather than having it ex tend down into the drain.

However, the generally vertical portion of the pipe 250 which extends into the drain does serve a useful demonstration purpose. That is, to show how little steam remains uncondensed, the damper 271 mnv be closed and the damper 275' opened. If then the cover of the drain 230 is removed, or if the hole in the cover of the drain through which the pipe 250 extends is slightly larger than the pipe, the steam passing down through the vertical part of the pipe 250 will tend to rise into the boiler room, providing a visual observation of the small quantity that actually remains uncondensed.

Thus, relative to the embodiment illustrated in FIGS. 1 to 5, in the embodiment of FIG. 7 the part of the pipe 250 leading to the drain has been provided with a damper 275 adjacent the drain so as in effect to close oil the pipe 250 between the elbow 251 and the drain and the water which was previously injected into the joint 251 has been omit-ted.

As discussed in connection with the embodiment of FIGS. 1 to 5, the embodiment shown in FIG. 7 can also be operated with the smoke stack damper 214 open.

Also, as discussed in connection with the embodiment of FIGS. 1 to 5, while it is preferred to have pipes within the tank 216 similar to the pipes 40a and 42a shown in FIGS. 2 and 4, the system would be operative without such U-shaped pipes within the tank 216, i.e., the pipes 240 and 242 would merely provide a communication with the top of the tank 216 and the pipe 250.

In FIG. 7 the pipe 276 has been shown connected to the boiler 210 to receive its steam and the pipe 263 may also receive its steam from the boiler 210.

This invention has been embodied in a boiler having an oil burner (FIG. 1) or 350 (FIG. 7); but it is seen that this invention is not limited to a particular type of boiler or fuel.

While the pipe 18b has been shown extending below the top of the tank 16, to form an outlet 20a, this has been shown for purposes of clarity, whereas in practice the pipe 18b is connected to the top of the tank 16 Without extending into the tank.

Further, while a steam injector has been discussed in connection with the pipe joint 60 to assist the flow of steam into the tank 16, it is seen that other assisting means, such as water flowing through a Venturi tube (not illustrated) in the pipe 18b, but adjacent the smoke stack and with the direction of water flow toward the tank could be provided, the water tending to also condense the steam to create a further vacuum, in addition to the Venturi effect.

In the embodiment of this invention, the soot removing method is performed once a day, when the demand for steam from the boiler is substantially reduced, i.e., during the noon lunch hour.

Further, the apparatus has been illustrated in the drawings primarily diagrammatically, because the various flanges and welded connections which may be used, but are not shown, may easily be provided by those skilled in the art.

Although direct water sprays have been shown to condense the steam it will be understood that other means for cooling and condensing the steam could also be provided.

Having described my invention, what I claim is:

1. A method for removing soot from boilers while minimizing air pollution comprising discontinuing fuel combustion within the boiler, spraying steam into said boiler so as to dislodge the soot from said boiler tubes, flowing said steam and soot through a first pipe means into a tank, and substantially condensing said steam laden soot in said tank so as to carry off the boiler tube soot in the condensed steam.

2. The method set forth in claim 1 and further comprising closing the smoke stack damper after fuel combustion is discontinued, and spraying water into said tank to condense said steam.

3. The method set forth in claim 2 and further comprising directing the sprayed -water and condensed steam together with the soot to a drain.

4. The method set forth in claim 3 and further comprising venting the top of said tank through a second pipe means to a drain.

5. The method set forth in claim 4 and further comprising spraying water into said second pipe means to condense any vented, uncondensed steam, and injecting steam into said first pipe means to further the flow of steam from said boiler to said tank.

6. The method set forth in claim 1 and further including opening a damper placed in said first pipe means so as to provide communication between said boiler and tank.

7. The method set forth in claim 4 wherein the top vented steam flows through a tortuous path.

8. The method set forth in claim 1 wherein said steam is directed into said tank in a downwardly direction and venting the top of the tank.

9. The method set forth in claim 8 and further including spraying water into said stream in said tank to condense the latter.

10. The method set forth in claim 9 wherein the top vented steam flows through a tortuous path.

11. Apparatus for removing soot from boiler tubes comprising, a boiler having tubes upon which soot collects, steam spray means attached to said boiler for dislodging said soot, a smoke stack connected to said boiler, a tank receiving and condensing a part of said steam, said smoke stack having a damper which is closed when said steam is sprayed, a pipe connected to said tank at one end and connected at the other end to said smoke stack between said boiler and said damper, said pipe directing the steam downwardly into said tank, and tortuous pipe means for muffling and and venting uncondensed steam from the upper part of said tank, said tank including pipe and spray means for spraying cooling water into said steam so as to condense said steam, and said pipe includes a steam injector to create a suction effect in said pipe to help the flow of steam from said boiler to said tank.

12. Apparatus for use with a boiler to remove soot from the boiler tubes comprising a tank, a main pipe connectable to said boiler and by which steam carrying soot is conducted to said tank, condensing means cooperating with said tank to condense said steam, tortuous pipe means partially within said tank to vent said tank to a drain, and a water sprayer within a part of said tortuous pipe means outside of said tank to substantially condense any remaining uncondensed steam.

13. Apparatus for use with a boiler to remove soot from the boiler tubes comprising a tank, a main pipe connectable to said boiler and by which steam carrying soot is conducted to said tank, condensing means cooperating with said tank to condense said steam, and vacuum producing means in said main pipe for increasing the flow of the steam from the boiler to the tank.

14. The combination recited in claim 13 and further including a damper in said pipe to close the communication between the tank and the boiler when the boiler is in normal operation.

15. The combination recited in claim 11 and further including drain means to permit the condensed steam and water to fiow into a drain.

16. The structure recited in claim 11 wherein said tortuous pipe means includes a further water spray means disposed there within to substantially condense any remaining uncondensed steam.

17. The structure recited in claim 13 wherein said condensing means includes a spray pipe to spray cooling water within said tank to condense said steam, and drain means to connect said tank to a drain, whereby the water and condensed steam carries the soot into the drain.

18. The structure recited in claim 12 in which said main pipe carries a damper to substantially close the communication between the boiler and the tank during normal operation of said boiler.

19. The method recited in claim 1 and further including venting to the atmosphere the noxious gases which flow from said boiler to said tank with said steam.

20. The combination recited in claim 11 and further including means connecting said tortuous pipe means with said smoke stack to vent to the atmosphere the noxious gases which flow from said boiler to said tank with said steam and any uncondensed steam.

21. The combination recited in claim 20 and further providing means for connecting said vent pipe to said drain or to said smoke stack.

22. The method set forth in claim 1 wherein the smoke stacks damper is kept open, and assisting with additional steam the flow of steam from said boiler to said tank.

References Cited UNITED STATES PATENTS 493,749 3/1893 Born ct a1 261-l7 1,103,304 7/1914 Lent 26117 XR 2,027,495 1/1936 Turner. 2,729,301 1/ 1956 Ekstrom 1 19 KENNETH W. SPRAGUE, Primary Examiner.

U.S. Cl. X.R. 122390

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