The invention relates to a cooling assembly for a wall box for a large-scale combustion device. The wall box is located within a wall port of the combustion device in order to receive a device, such as a cleaning device or an imaging device.
During the operation of large-scale combustion devices, such as boilers that burn fossil fuels, slag and ash encrustations develop on interior surfaces of the boiler. The presence of these deposits degrades the thermal efficiency of the boiler. Therefore, it is periodically necessary to remove such encrustations. Various systems are currently used to remove these encrustations.
One such type of system includes a device referred to as a “sootblower”. Sootblowers are used to project a stream of cleaning fluid, such as air, steam or water, into the interior volume of the boiler. In the case of long retracting type sootblowers, a lance tube is periodically advanced into and withdrawn from the boiler. As the lance tube is advanced into and withdrawn from the boiler, it rotates or oscillates in order to direct one or more jets of cleaning fluid at desired surfaces within the boiler. In the case of stationary sootblowers, the lance tube is always maintained within the boiler. Sootblower lance tubes project through openings in the boiler wall, referred to as wall ports. The wall ports may include a mounting assembly, such as a wall box, in order to properly position the lance tube with respect to the boiler wall.
Another such type of system includes a device commonly referred to as a “water cannon”. Water cannons involve the use of a monitor or nozzle positioned within a wall port in order to eject a stream of fluid, such as water, into the interior volume of the combustion device. The water cannon nozzle typically includes a pivot joint to permit adjustment of the direction of the stream of fluid. Similarly to the sootblower, the water cannon nozzle is positioned within the wall port via a mounting assembly, such as a wall box. Unlike the sootblower, however, the water cannon nozzle preferably includes a pivotable ball joint coupled with the wall box in order to adjust the direction of the stream of fluid flowing into the boiler interior volume. Due to the presence of the pivotable ball joint, the wall port for a water cannon assembly is typically larger than the wall port for a sootblower.
Other devices, besides cleaning devices, may penetrate the boiler wall via a wall port in order to perform a desired function. One such device is an imaging device, such as an infrared imaging device. Imaging devices are often used to examine the interior volume and the interior surfaces of the boiler in order to check the boiler status or to perform maintenance on the boiler. Similarly to the cleaning devices, the imaging device typically penetrates a wall port in order to view the boiler interior volume. The imaging device may be extended into the boiler interior volume similarly to a sootblower lance, it may be coupled with a pivoting ball joint similarly to a water cannon assembly, or it may be used in any other appropriate configuration. Regardless of the configuration of the imaging device, it typically includes a mounting assembly located within the boiler wall port.
During operation of the boiler, the boiler interior volume reaches extremely high temperatures. The boiler external walls include a plurality of tubes containing a fluid, such as steam or water, that flows through the tubes and undergoes heat exchange with the boiler interior volume gases. The heated fluid may then be used for various purposes, such as a heating medium. The tubes, hereinafter referred to as steam tubes, are typically placed side-by-side with each other in order to form a substantially continuous heat-transferring medium. However, the steam tubes must be diverted or discontinued in the area near the wall port in order to permit the penetrating device, such as the sootblower lance tube, the water cannon nozzle, or the imaging device, to penetrate the wall of the boiler. As a result, the area adjacent to the wall port is more directly exposed to the heated boiler gases than other areas of the boiler wall.
Currently, the area adjacent to the wall port is at least partially protected from the heated boiler gases by various methods. One such method is to provide a heat transfer plate that conducts heat from the boiler interior volume into the steam tube. More specifically, heat shields may be located adjacent to the wall port and connected to the steam tubes in order to conduct heat from the boiler gases into the steam tubes and prevent such heat from damaging or penetrating the wall box. Similarly, a crotch plate may be located adjacent to the wall port and connected to the steam tubes in order to conduct heat from the boiler gases into the steam tubes. Another such method of protecting the wall box is to provide a layer of refractory material adjacent to the wall port in order to absorb and/or resist the boiler gas heat.
One problem with the currently-used methods of protecting the wall box is that the refractory material, the heat shields, and crotch plate may undergo part wear over time, thus lessening the respective components' effective heat-reducing capabilities. Part wear may be further hastened by the high temperatures within the boiler interior volume. Another problem with the currently-used methods is that the refractory material, the heat shields, and crotch plate, even when fully intact, may not provide enough heat-reducing properties to sufficiently protect the wall box.
As seen from above, it is desirous to provide an improved system for protecting and cooling a wall box in order to improve the performance of the wall box, in order to improve the performance of the device coupled with the wall box, and in order to prevent premature component damage of both the wall box and the device.
In overcoming the disadvantages and drawbacks of the known technology, the current invention provides a cooling chamber for cooling a wall box located within a wall port of a combustion device. The combustion device, hereinafter referred to as a boiler, includes an interior volume defined by a wall. A device is coupled with the wall box in order to perform a desired function. One such device is a cleaning device that projects a cleaning fluid into the interior volume of the boiler. The cleaning device typically projects fluid into the boiler interior volume by extending into the boiler interior volume or by being pivotably mounted with the wall box. Another such device is an infrared imaging device used to generate images of the boiler interior volume and interior components. Yet another such device is a servicing device for reaching into the boiler interior volume and servicing interior components.
In order to cool the wall box from high boiler interior volume temperatures, the wall box includes a cooling chamber surface defining a cooling chamber located adjacent to the wall port. The cooling chamber includes an inlet and an outlet, wherein the inlet and the outlet are both located exterior from the combustion device.
The cooling chamber may further include a cooling fluid configured to enter the cooling chamber via the inlet and to exit the cooling chamber via the outlet. The cooling fluid is configured to absorb heat from the cooling chamber surface. Additionally, the cooling chamber may include at least one vane configured to direct the cooling fluid from the inlet of the cooling chamber to the outlet. The cooling fluid is preferably air, water, or steam.
The wall box may further include a sealing chamber surface defining a sealing chamber located adjacent to the wall port. The sealing chamber includes a sealing chamber inlet and a sealing chamber outlet, and the sealing chamber outlet is in fluid communication with the interior volume of the combustion device. The cooling chamber is located such that at least a portion of the cooling chamber is located between the combustion device and the sealing chamber.
The sealing chamber may further include a sealing fluid configured to enter the sealing chamber via the sealing chamber inlet and to exit the sealing chamber via the sealing chamber outlet. The sealing fluid flowing out of the sealing chamber outlet enters the interior volume of the combustion device. The sealing fluid is preferably air or steam. Alternatively, the sealing fluid may be any other appropriate fluid.
In another aspect of the invention, a cooling assembly is provided, including: a temperature sensor located adjacent to the wall port and configured to obtain an operating temperature; a cooling chamber surface defining a cooling chamber configured to receive a cooling fluid; and a controller configured to control a characteristic of the cooling fluid. The cooling chamber is located adjacent to the wall port. The cooling fluid is configured to adjust the operating temperature.
Furthermore, the controller may be configured to actively control the characteristic of the cooling fluid based on the operating temperature. A second temperature sensor may also be provided within the cooling chamber in order to obtain a second operating temperature. Additionally, the controller may be configured to actively control the characteristic of the cooling fluid based on the second operating temperature. In one configuration, the characteristic of the cooling fluid is the flow rate of the cooling fluid.
Referring now to the present invention,
The wall port 18 is of sufficient size such that a cleaning device may be inserted into the wall port 18 in order to clean slag and ash from the interior surfaces of the boiler. As discussed above, one such cleaning device, commonly referred to as a sootblower, includes a long lance tube that is inserted into the boiler. The lance blower typically rotates or oscillates while spraying a fluid from lance tube nozzles. Sootblowers typically require a wall box opening to be slightly larger than the outer diameter of a lance tube, which is typically less than 6 inches. Another type of cleaning device, commonly known as water cannon, includes a nozzle positioned adjacent to the wall port 18. Instead of extending into the boiler interior volume, a water cannon typically includes a pivoting ball joint in order to adjust the direction of fluid stream flowing from the water cannon nozzle and into the boiler interior volume. Due to the size of the pivoting joint, water cannons typically require a larger wall port 18 than sootblowers. More particularly, water cannon wall ports 18 are typically a square shape having dimensions of 8 inches by 8 inches.
Due to the relatively small size of the wall ports 18, aspects of the present invention are not as likely to be used in connection with sootblower wall ports as they are to be used in connection with water cannon wall ports 18. However, it may be particularly advantageous to use aspects of the present invention with other devices that may require large openings, such as optical imaging devices or burners.
The wall box 10 shown in
The boiler tubes 12 shown in
The wall box 10 shown in
Referring back to
Another such opening for sealing fluid, as shown in
The first stream 60 and second stream 68 of sealing fluid preferably exit the sealing chamber 52 with a velocity sufficient to prevent boiler gases, soot, and other debris from exiting the boiler interior volume 54 via the respective openings 56, 62.
In order to form a more secure connection between the refractory material 80 and the wall box 10, saddle-horns 42 are preferably welded to the heat shields 38, 40. More specifically, the saddle-horns 42 preferably include enlarged-diameter head portions 82 that provide an anchor-type connection for the refractory. Alternatively, a T-shaped component or a plate having a plurality of bent portions may be used as saddle-horns. Similarly, saddle-horns 46 having enlarged-diameter head portions are also preferably welded to the crotch plate 44. The saddle-horns 46 may include similar alternative configurations.
Passive heat-protection components, such as the heat shields 38, 40, the crotch plate 44, and the refractory material 80 may not sufficiently protect the wall box 10 from the heat of the boiler interior volume 54. Insufficient protection from the heat is especially problematic with water cannon assemblies 70, such as the one shown in
Referring to
Referring to
The vanes 100a, 100b, 104a, 104b, 106a, 106b, 108a, and 108b preferably have a height substantially equal to the height of the cooling chamber 88 in order to maximize flow control. A material appropriate for the high boiler temperatures is preferably used to construct the vanes 100a, 100b, 104a, 104b, 106a, 106b, 108a, and 108b.
As shown in
As shown in
Referring now to
Additionally, the cooling chamber 88 is further separated from the refractory material 80 in the area near the wall port 18 by a cooling chamber front wall 124 having an inner surface 126 in the cooling assembly 84. The cooling chamber 88 is preferably defined by a plurality of plates (the divider ring 102, the outer edges of the cooling chambers 112a, 112b, the cooling chamber bottom wall 118, the divider wall 120, the divider wall 122, and the cooling chamber front wall 124) integrally formed via a coupling method such as welding. However, the cooling chamber 88 may be defined by a single, unitary structure formed by an appropriate method, such as casting, molding, or stamping.
In order to prevent the cooling fluid from damaging the cooling chamber 88, the components defining the cooling chamber 88 are preferably comprised of a non-corrosive material, such as stainless steel. Similarly, the components defining the sealing chamber 52 are also preferably comprised of a non-corrosive material, such as stainless steel.
The cooling assembly 84 shown in
An inner cooling sensor 128 is shown in
As shown in
The sealing chamber 52 may also include at least one temperature sensor in order to measure the operating temperature of the wall box 10. As shown in
As shown in
The controller 132 may also be in electrical connection with a warning device 146 such as a flashing warning light or a warning siren. The warning device 146 is programmed to send an audio or a visual warning to the appropriate system user if the wall box 10 reaches a predetermined warning temperature.
Various configurations may be used for operating the cooling assembly 84. In one configuration, the cooling fluid is supplied continuously to the cooling chamber 88 regardless of the operating temperature of the wall box 10. This configuration does not necessarily include sensors to measure the operating temperature of the wall box 10.
In another configuration of the cooling assembly 84, the cooling fluid is only supplied when a predetermined event occurs, such as the operating temperature of the wall box 10 reaching a predetermined cooling temperature. The predetermined cooling temperature may be equal to or unequal to the predetermined warning temperature depending on user preferences. During this configuration, the wall box 10 preferably includes temperature sensors similarly to those discussed above. Another predetermined event that may activate the cooling fluid flow is a component failure, such as a failure of the heat shields 38, 40 the crotch plate 44, or the refractory material 80. Failure of respective components may be determined by the temperature sensors described above, or by other appropriate methods such as sensors connected to the respective components.
In yet another configuration of the cooling assembly 84, the cooling fluid is regulated by a manual control, such as a control knob (not shown). The control knob may be configured to adjust any appropriate characteristic of the cooling fluid, such as flow rate, fluid temperature, or fluid content. The control knob may also be an override switch that is used to override the controller 132. The control knob is especially beneficial during periods of maintenance on the wall box 10 because the boiler tubes 12 and the water cannon lance tube 72 do not necessarily conduct fluid flow during these periods.
In another configuration of the present invention, equally applicable to each of the above described configurations, the controller 132 controls a parameter of the cooling fluid other than the flow rate, such as the fluid temperature or the fluid composition. For instance, the controller 132 may include a cooler (not shown) in order to sufficiently cool the cooling fluid based on the cooling chamber surface 87 operating temperature. Furthermore, the controller 132 may include a mixer to inject various different fluids into the stream of cooling fluid based on the operating temperature of the wall box 10. Preferably, the cooling fluid is tempering air during relatively low wall box 10 operating temperatures, it is compressed air during medium wall box 10 operating temperatures, and it is moist air having a higher cooling potential during relatively wall box 10 operating temperatures. Alternatively, the various different fluids may have different heat-absorbing properties, and they may include combinations of water, air, and refrigerants.
It is therefore intended that the foregoing detailed description be regarded as illustrative rather than limiting, and that it be understood that it is the following claims, including all equivalents, that are intending to define the spirit and scope of this invention.
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