SOOTBLOWER HAVING A ROTATIONAL DELAY MECHANISM

Abstract

A sootblower to project a blowing medium into a boiler is disclosed herein. The sootblower includes a hub, in which a first end of the hub is configured to receive a lance and a second end of the hub is configured to receive the blowing medium. The sootblower further includes a drive assembly configured to convert bidirectional rotation from a drive shaft to bidirectional rotation for the hub. The drive assembly then includes a rotation delay mechanism configured to delay a transition between a first directional rotation and a second directional rotation of the bidirectional rotation for the hub with respect to the drive shaft when the drive shaft is transitioning from a first directional rotation to a second directional rotation of the bidirectional rotation for the hub.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit, under 35 U.S.C. § 119, of U.S. Provisional Application Ser. No. 60/911,245, filed on Apr. 11, 2007 and entitled “Sootblower Having a Rotational Delay Mechanism” in the name of W. Wayne Holden and Michael C. Holden. The disclosure of this U.S. Provisional Application is incorporated herein by reference in its entirety.

BACKGROUND OF DISCLOSURE

Field of the Disclosure

Embodiments disclosed herein generally relate to sootblowers. More specifically, embodiments disclosed herein relate to an improved sootblower used to project a stream of a sootblower medium within a combustion device.

Generally when combusting fuel in large boilers, as used in electric and steam generating plants, or in recovery boilers, as used in paper and pulp mills, large quantities of particulate matter from burned fuel may quickly accumulate within the interior surfaces and tubes of the boilers. Specifically, the particulate matter, such as soot and tar, may accumulate on the heat exchanger surfaces and tubes in these boilers to significantly reduce the boilers' efficiencies. To prevent such particulate matter buildup, sootblowers may be used to provide a substantially continuous cleaning of the interior surfaces of the boilers.

Typically, sootblowers are permanently installed between adjacent rows of heat exchanger tubes within a boiler so that the sootblowers may provide regular, if not substantially continuous, cleaning without the need for the boiler to be taken out of service during the cleaning. As such, it is common for each of the large boilers and the paper mill boilers to have up to fifty or more sootblowers attached for cleaning. To maintain operating efficiency, each sootblower may be operated on a regular cycle, such as about once an hour, depending on the size of the boiler and severity of the accumulation of particulate matter.

One commonly used sootblower are long retracting sootblowers. Examples of long retracting sootblowers are shown and described in U.S. Pat. Nos. 5,675,863 and 5,745,950, which are incorporated by reference in their entirety. These sootblowers generally include a long pipe or lance having a nozzle at the end for directing a blowing medium, such as steam or another vapor, onto the surfaces of the heat exchanger tubes. An example of a lance 102 cleaning a boiler 190 is shown in FIG. 1. Lance 102, having nozzles 104 at an end for directing a blowing medium 106, is inserted through a hole 194 of a wall 192 of boiler 190. Lance 102 usually is sufficient in length such that the entire length of heat exchanger tubes 196 of boiler 190 may be accessed by lance 102. Lance 102 is then usually attached to a moveable carriage or housing with a motor (not shown) to reciprocate and rotate (as indicated by arrows) lance 102 within boiler 190 for effective cleaning. As such, upon actuation, lance 102 may reciprocate into boiler 190 and rotate at a generally continuous speed. Blowing medium 106 is then exerted through nozzles 104 as lance 102 is in motion, thereby blowing off accumulated particle matter 198 and cleaning heat exchanger tubes 196.

When actuated and reciprocated into and out-of the boiler, the lance generally will follow a standard helical path, as shown in FIG. 2. Specifically, the nozzle of the lance may follow path 280 when extended into and retracted from the boiler. However, as the nozzle follows path 280, substantial portions of the boiler and the heat exchanger tubes may fail to be reached by blowing medium from the nozzle of the lance. Thus, particulate matter may still accumulate on the boiler's internal surfaces and heat exchanger tubes that do not fall within path 280 of the nozzle of the lance. Accordingly, there exists a need for a sootblower that may improve the coverage of the nozzle of the lance to provide more coverage when cleaning boilers, thereby increasing the efficiency of the boilers.

SUMMARY OF CLAIMED SUBJECT MATTER

In one aspect, embodiments disclosed herein relate to a sootblower to project a blowing medium into a boiler. The sootblower includes a hub, in which a first end of the hub is configured to receive a lance and a second end of the hub is configured to receive the blowing medium. The sootblower further includes a drive assembly configured to convert bidirectional rotation from a drive shaft to bidirectional rotation for the hub. The drive assembly then includes a rotation delay mechanism configured to delay a transition between a first directional rotation and a second directional rotation of the bidirectional rotation for the hub with respect to the drive shaft when the drive shaft is transitioning from a first directional rotation to a second directional rotation of the bidirectional rotation for the hub.

In another aspect, embodiments disclosed herein relate to a drive assembly for a sootblower to project a blowing medium into a boiler. The drive assembly includes a drive shaft, a static member attached to the drive shaft, and a spur gear disposed about and configured to rotate about the drive shaft. One of the static member and the spur gear includes a pint attached thereto, and the other of the static member and the spur gear includes a slot formed therein. The pin then slidably engages the slot.

In yet another aspect, embodiments disclosed herein relate to a sootblower used to project a blowing medium. The sootblower includes a housing having a lubricant disposed therein, roller rotatably attached to the housing and configured to travel along tracks, and bearing disposed inside of the rollers. The bearings of the rollers are in fluid communication with the housing.

Other aspects and advantages of the invention will be apparent from the following description and the appended claims.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows a view of a prior art lance attached to a sootblower.

FIG. 2 shows a view of helical path of a prior art sootblower.

FIG. 3 shows a top-down view of a sootblower in accordance with embodiments disclosed herein.

FIG. 4 shows a cross-sectional view taken along line A-A of the sootblower shown in FIG. 3 in accordance with embodiments disclosed herein.

FIG. 5 shows a perspective view of a spur gear in accordance with embodiments disclosed herein.

FIG. 6 shows a view of a helical path of a sootblower in accordance with embodiments disclosed herein.

DETAILED DESCRIPTION

In one aspect, embodiments disclosed herein relate to an improved sootblower with a rotation delay mechanism. The rotation delay mechanism may include one member with a pin to engage or another member with a slot. In another aspect, embodiments disclosed herein relate to a drive assembly having a static member attached to a drive shaft and a spur gear disposed about the drive shaft. A pin is attached to one of the static member and the spur gear, and a slot is formed in the other of the static member and the spur gear. In yet another aspect, embodiments disclosed herein relate to a sootblower configured to have bearings of rollers in fluid communication with a housing of the sootblower, thereby allowing lubricant disposed within the housing to flow between the bearings and the rollers.

Referring to FIG. 3, a sootblower 300 in accordance with embodiments disclosed herein is shown. Sootblower 300 includes a housing 301 configured to receive a lance 302. Lance 302 may have a long, tubular construction and include one or more nozzles 304. As shown, nozzle 304, preferably a venturi nozzle, is disposed at the end of lance 302. However, those having ordinary skill in the art will appreciate that the invention is not so limited, and the nozzle may be disposed at any location on or about the lance. Nevertheless, lance 302 is configured to connect with a hub 310, such as connecting a flange 308 of lance 302 with a flange 312 of hub 310.

Hub 310 may be rotationally disposed within housing 301 such that hub 310 is able to rotate with respect to housing 301. As such, when hub 310 rotates, lance 302 will accordingly rotate therewith. Further, hub 310 is configured to receive a blowing medium, such as through a feed tube 317. As shown, a valve 316 may supply the blowing medium to feed tube 317, in which the blowing medium may then be transported through hub 310 to lance 302 to exert the blowing medium through nozzle 304. In one embodiment, the blowing medium used may be steam, such as superheated steam of about 750° F. (400° C.); however, any high-pressure and/or high-temperature vapor or gas known in the art may be used.

Sootblower 300 further includes a motor 318 configured to supply power and provide rotational movement to hub 310 and translational movement to housing 301. Specifically, using a drive assembly disposed within housing 301, motor 318 rotates hub 310 and lance 302, in addition to moving housing 301 along tracks 322. In one embodiment, rollers 320 may be rotatably attached to housing 301. As shown in FIG. 3, rollers 320 are rotatable attached to housing 301 through legs 324. Rollers 320 may then travel along tracks 322 to support the weight and enable translational movement for sootblower 300. Thus, when used in a boiler cleaning application, the lance of the sootblower may be reciprocated into and out-of the boiler while rotating. An example of motor 318 that may be used within sootblower 300 is a 1,750 revolutions per minute (183 radians per second), 2 horsepower (1.5 kilowatts) electric motor. Those having ordinary skill in the art though will appreciate that any suitable motor may be used.

Referring now to FIG. 4, a view of a cross-section taken along line A-A of sootblower 300 of FIG. 3 in accordance with embodiments disclosed herein is shown. Sootblower 300 includes a drive assembly 330 disposed within housing 301. Generally, drive assembly 330 is configured to receive bidirectional rotation from the motor (e.g., 318 shown in FIG. 3) of the sootblower. This bidirectional rotation is then converted by drive assembly 330 into bidirectional rotation for hub 310. Thus, as the housing of the sootblower travels back-and-forth along the tracks to extend and retract the lance within the boiler, the lance will accordingly transition back-and-forth between rotational directions.

For example, when the sootblower is translationally moving along the track towards the boiler with the lance being extended into the boiler, the motor and the hub/lance may rotate in the clockwise direction. Then, when the sootblower is translationally moving along the track away from the boiler with the lance being retracted from the boiler, the motor and the hub/lance may reverse directions to rotate in the counter-clockwise direction. Thus, bidirectional rotation from the motor is convened into bidirectional rotation for the hub and the lance attached thereto.

Further, in addition to converting the rotation from the motor to the hub 310, drive assembly 330 may be used to delay the transition between the rotational directions from the motor to hub 310. Such a delay may include temporarily stopping the hub or discontinuing to provide rotation to the hub when the motor switches directions. For example, when the motor transitions from rotating in a clockwise direction to rotating in a counter-clockwise direction, the transition of rotation of the hub/lance may have a delay from the transition of rotation of the motor. This delay between the transition of the motor and the transition of the hub/lance may thereby allow the nozzle of the lance to provide more coverage when cleaning the sootblowers, essentially allowing the nozzle to follow different helical paths when extending within and retracting from a boiler. This delay between the transition of the motor and the transition of the hub/lance is described further below.

Referring still to FIG. 4, motor 318 generally provides bidirectional rotation to a drive shaft 340 of drive assembly 330. Specifically, the motor may provide bidirectional rotation to a worm 326. Worm 326, disposed within housing 301, is configured to bidirectionally rotate, corresponding to the bidirectional rotation of the motor. For example, as the motor rotates clockwise and then counter-clockwise, worm 326 may correspondingly rotate clockwise then counter-clockwise. Worm 326 is then configured to engage a worm gear 342, attached to drive shaft 340. As such, the motor is configured to bidirectionally rotate drive shaft 340 from the engagement of worm gear 342 with worm 326. When drive shaft 340 bidirectionally rotates then, drive shaft 340 will rotate about a drive shaft axis 341. In selected embodiments, the arrangement of worm 326 and worm 342 may take advantage of ratios of revolutions therebetween, in which the ratio of revolutions of the worm to the worm gear may be of the magnitude of about 1:36. Those having ordinary skill in the art, though, will appreciate that the invention is not so limited, and any arrangement and ratio between the worm and the worm gear may be used.

Drive shaft 340, powered by the motor using, for example, worm 326 and worm gear 342, may then be used to provide translational motion for housing 301, in addition to providing rotation for hub 310. As such, to provide translational motion for housing 301, pinion gears 346 may be attached to the ends of drive shaft 340. Pinion gears 346 may be configured to engage a rack 348, as shown formed along the bottom of tracks 322. Specifically, for example, teeth of pinion gears 346 may be configured to engage teeth of rack 348 to transfer the rotation from drive shaft 340 and pinion gears 346 into translational motion for housing 301 of sootblower 300. Thus, by switching rotational directions of the motor, the translational direction of housing 301 may be controlled through drive shaft 340 with pinion gears 346 and rack 348.

Further, to provide rotation for hub 310, a rotation delay mechanism 350 is attached to drive shaft 340. Rotation delay mechanism 350 is configured to transmit rotation from drive shaft 340 to a gear train 360. As such, when rotation delay mechanism 350 is engaged and transmitting rotation from drive shaft 340 to gear train 360, rotation delay mechanism 350 will delay the transition between rotational directions from drive shaft 340 to gear train 360.

Referring still to FIG. 4, rotation delay mechanism 350 may include a static member 352 and a spur gear 354. Static member 352 is attached to drive shaft 340, and spur gear 354 is disposed about drive shaft 340. Additionally, spur gear 354 is configured to rotate, at least partially, about drive shaft 340. As shown, static member 352 includes pins 356 attached thereto and spur gear 354 includes slots 358 formed therein. Pins 356 are then configured to be disposed within slots 358, thereby enabling pins 356 to slidably engage slots 358. As used herein, “slidably engage” refers to the ability of a pin to be disposed within a slot, in which the pin may slide within the slot from one end of the slot to the other end of the slot.

For example, referring briefly to FIG. 5, spur gear 354 having slots 358 formed therein in accordance with embodiments disclosed herein is shown. Pins 356 are disposed within slots 358, in which pins 356 are configured to slidably engage slots 358. Specifically, when slidably engaging slots 358, pins 356 are configured to slide within slots 358 from one end of slots 358 to the other end. As such, pins 356 are then configured to slide within slots 358 such that pins 356 may rotate with respect to drive shaft axis 341. Specifically, in this embodiment, pins 356 may rotate by about 60 degrees with respect to drive shaft axis 341. Those having ordinary skill in the art will appreciate that the invention is not so limited though, in which the slots may be of any size and shape to slidably engage with the pins such that the pins may rotate up to about 180 degrees with respect to the drive shaft axis.

Referring again to FIG. 4, rotation delay mechanism 350 uses slidable engagement of pins 356 disposed within slots 358 to delay the transition between rotational directions from drive shaft 340 to gear train 360. For example, when drive shaft 340 transitions from rotating clockwise to the counter-clockwise, the transition of rotation of drive shaft 340 also changes the rotation of static member 352 having pins 356 attached thereto. However, because pins 356 slidably engage slots 358 of spur gear 354, static member 352 will not engage spur gear 354 to rotate until pins 356 contact the ends of slots 358. Upon the contact of pins 356 with the ends of slots 358, the rotation of static member 352 with respect to spur gear 354 will be prevented, at which point drive shaft 340 may then engage and rotate spur gear 354, and spur gear 354 may then engage and rotate gear train 360.

As shown, gear train 360 is configured to rotate hub 310, corresponding to the direction of rotation of drive shaft 340. In this embodiment, gear train 360 includes a spur gear 362 with a bevel gear 364 attached thereto. Spur gear 354 of rotation delay mechanism 350 is configured to engage spur gear 362 of gear train 360 through, for example, the engagement of teeth (not shown) formed thereon. As spur gear 354 rotate, this rotational motion is translated through spur gear 362 to rotate bevel gear 364. Bevel gear 364 is then configured to engage and rotate hub 310. Specifically, bevel gear 364 may engage a bevel gear 311 attached to and/or formed upon hub 310. As such, through engagement of teeth (not shown), for example, bevel gear 364 may rotate bevel gear 311 of hub 310.

Referring to FIG. 6, a helical path 680 of a sootblower in accordance with embodiments disclosed herein is shown. In this embodiment, the sootblower includes a rotation delay mechanism (e.g., 350 in FIG. 4) to delay the transition between rotational directions from the drive shaft to the hub. As shown, when first extended into the boiler, a nozzle of a lance attached to the hub may follow an extension path 682. Upon full extension into the boiler, the motor of the sootblower may then switch directions to retract the lance from the boiler.

However, because of the inclusion of the rotation delay mechanism within the sootblower, the hub and lance may have a delay in transitioning rotational directions from the drive shaft to the hub. Thus, when retracted from the boiler, the nozzle may follow a retraction path 684, distinct and offset from extension path 682. For example, by including rotation delay mechanism 350 in sootblower 300, which includes slots 358 allowing pins 356 to rotate by about 60 degrees with respect to drive shaft axis 341, extension and retraction paths 682 and 684 may be offset by about 60 degrees from one another. As such, when the extension and retraction paths are distinct and offset, the path of the nozzle may be improved to cover more area than that of the standard helical path (shown in FIG. 2) when cleaning.

Those having ordinary skill in the art will appreciate that the present disclosure is not limited to a specific arrangement for the rotation delay mechanism. For example, other arrangements of the pins and slots may be used instead. In one embodiment, rather than having the pins attached to the static member and the slots formed in the spur gear in FIG. 4, the pins may be attached to the spur gear and the slots may instead be formed in the static member. Further, in another embodiment, the static member may be eliminated altogether, in which, in FIG. 4, the pins may be attached to the worm gear to slidably engage the spur gear. Furthermore, rather than being limited to the use of pins and slots within the rotation delay mechanism, other similar engagements known in the art may also be used. Thus, those having ordinary skill in the art will appreciate that other embodiments and arrangements of the rotation delay mechanism may be formed which do not escape the scope of the present disclosure.

Further, the hub, the drive shaft, and the drive assembly may be disposed within the housing of the sootblower and submerged in a lubricant. For example, a lubricant of synthetic oil, or any other lubricant known in the art, may be disposed and sealed within the housing of the sootblower. This may be used to preserve and maintain the moving parts disposed within the housing of the sootblower. In such an embodiment, the rollers rotatably attached to the housing and bearings disposed therein may be in fluid communication with the housing. For example, referring back to FIG. 4, bearings 328, used to facilitate rotation of roller 320, are disposed within roller 320. Sootblower 300 may then include a passage 329 extending between roller 320 and housing 301. Specifically, passage 329 may be formed inside leg 324, in which lubricant may flow between bearings 328 of roller 320 and housing 301. Thus, rather than having to continuously replace the lubricant of the bearings within the rollers, these bearings may instead draw from the lubricant disposed inside the housing.

Furthermore, as also shown in FIG. 4, hub 310 may be positioned substantially on a vertical centerline 331 of housing 301. In such an embodiment, this enables the majority of the weight of the sootblower (distributed at the hub from the lance and feed tube attached thereto) to be evenly distributed along the drive shaft and amongst the rollers of the sootblower to have a balanced design.

Embodiments of the present disclosure may provide for one or more of the following advantages. First, embodiments disclosed herein may provide a more efficient cleaning of boilers because of the different and varying paths used by the nozzles. Specifically, the nozzle may have an increased amount of paths to follow when cleaning boilers, thereby improving coverage when cleaning. Next, embodiments disclosed herein may provide a more economical sootblower for cleaning of boilers. For example, as shown, the sootblower described herein may only include one motor, thereby preventing cost of an additional motor. Further, embodiments disclosed herein may provide for a sootblower with an increased working life. For example, because the sootblower described herein may incorporate a balanced design, in addition to lubricant disposed therein, the working life of the sootblower may be extended by preventing unnecessary wear of parts.

While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the attached claims.

Claims

1. A sootblower to project a blowing medium into a boiler, the sootblower comprising:

a hub, wherein a first end of the hub is configured to receive a lance and a second end of the hub is configured to receive the blowing medium; and

a drive assembly configured to convert bidirectional rotation from a drive shaft to bidirectional rotation for the hub;

wherein drive assembly comprises a rotation delay mechanism configured to delay a transition between a first directional rotation and a second directional rotation of the bidirectional rotation for the hub with respect to the drive shaft when the drive shaft is transitioning from a first directional rotation to a second directional rotation of the bidirectional rotation for the hub.

2. The sootblower of claim 1, wherein the drive assembly comprises a rotation delay mechanism comprising a first member with a slot formed therein and a second member having a pin attached thereto, wherein the pin of the second member is configured to be disposed within the slot of the first member.

3. The sootblower of claim 2, wherein one of the first member and the second member comprises a static member attached to the drive shaft, wherein the other of the first member and the second member comprises a spur gear disposed about and configured to rotate about the drive shaft.

4. The sootblower of claim 1, wherein the hub connects the lance to a feed line supplying the blowing medium to the sootblower.

5. The sootblower of claim 1, further comprising a housing to contain the drive shaft, the hub, and the rotation delay mechanism.

6. The sootblower of claim 5, further comprising a lubricant disposed within the housing.

7. The sootblower of claim 5, wherein the hub is positioned substantially on a vertical centerline of the housing.

8. The sootblower of claim 1, further comprising pinion gears attached to the drive shaft, wherein the pinion gears are configured to engage a rack to provide translational motion for the sootblower.

9. The sootblower of claim 1, wherein the blowing medium is steam.

10. The sootblower of claim 1, wherein the lance comprises a venturi nozzle to emit the blowing medium.

11. The sootblower of claim 1, further comprising a worm gear attached to the drive shaft, wherein a motor is configured to provide bidirectional rotational motion to a worm engaging the worm gear, thereby providing bidirectional rotational motion for the drive shaft.

12. A drive assembly for a sootblower to project a blowing medium into a boiler, the drive assembly comprising:

a drive shaft;

a static member attached to the drive shaft; and

a spur gear disposed about and configured to rotate about the drive shaft;

wherein one of the static member and the spur gear comprises a pin attached thereto;

wherein the other of the static member and the spur gear comprises a slot formed therein; and

wherein the pin slidably engages the slot.

13. The drive assembly of claim 12, wherein when the pin slidably engages the slot, the pin is configured to rotate by about 60 degrees within the slot with respect to an axis of the drive shaft.

14. The sootblower of claim 12, wherein the drive shaft, the static member, and the spur gear are disposed within a housing.

15. The sootblower of claim 14, further comprising a lubricant disposed within the housing.

16. The sootblower of claim 15, further comprising rollers rotatably attached to the housing with bearings disposed therein, wherein the bearings of the rollers are in fluid communication with the housing such that the lubricant disposed within the housing flows into the rollers to lubricate the bearings.

17. The sootblower of claim 16, wherein the lubricant comprises synthetic oil.

18. A sootblower used to project a blowing medium, the sootblower comprising:

a housing having a lubricant disposed therein;

rollers rotatably attached to the housing and configured to travel along tracks; and

bearings disposed inside of the rollers;

wherein the bearings of the rollers are in fluid communication with the housing.

19. The sootblower of claim 18, wherein the lubricant comprises synthetic oil.

20. The sootblower of claim 18, further comprising:

a hub disposed within the housing, wherein a first end of the hub is configured to receive a lance and a second end of the hub is configured to receive the blowing medium; and

a drive assembly disposed within the housing, wherein the drive assembly is configured to convert bidirectional rotation from a drive shaft to bidirectional rotation for the hub.