US20060070722A1

US20060070722A1 - Air cannon manifold

Info

Publication number: US20060070722A1
Application number: US10/956,741
Authority: US
Inventors: Jefferson Shelton; Chris Landers
Original assignee: Individual
Current assignee: Martin Engineering Co; Halcyon Technologies Inc
Priority date: 2004-10-01
Filing date: 2004-10-01
Publication date: 2006-04-06
Also published as: WO2006039410A3; WO2006039410A2

Abstract

An apparatus for cleaning deposits from the interior surfaces of an industrial vessel, such as a kiln. The apparatus utilizes an air cannon manifold for selectively directing and venting a high volume of pressurized fluid to any one or more of a plurality of access ports defined in the vessel whereby the pressurized fluid is directed at the deposits to prevent them from adhering and accumulating on the walls of the vessel. A controller is provided to permit selection of a desired exhaust port for directing the pressurized fluid to the access ports and for sequencing an inlet valve in cooperation with a desired exhaust port.

Description

FIELD OF THE INVENTION

The instant invention relates to air cannons used for cleaning and preventing the buildup of deposits on the walls of industrial vessels, such as kilns used in the cement and paper industries. More particularly, the instant invention relates to a manifold for selectively directing the blast from an air cannon to any one of a plurality of ports of an industrial vessel for removing and preventing the build up of material deposits therein.

BACKGROUND OF THE INVENTION

In industrial vessels, such as cement, wood or paper kilns, and their associated structures, the accumulation of particulate deposits on the inner linings of these vessels is a recurring problem. Buildup of deposits in areas such as preheater and riser ducts can choke off feed pipes and cyclones and greatly affect the efficiency and production performance of the vessel, even to the point of causing unscheduled shutdowns. If deposits are permitted to accumulate the high temperatures typically encountered in vessels, such as kilns, will cause the deposits to become encrusted on the kiln's interior surfaces. The precise characteristics of the buildup in these vessels may vary from plant to plant, the process employed, and can even vary from hour to hour within the same plant or process.
Usually, the buildup begins sticking to the walls of the vessel lining with the consistency of talcum powder. Routine cleaning of the deposits is a preferred method of addressing the problem such that the deposits are removed before significant accumulation and encrustation occurs.
Air cannons have long been an accepted method for routine cleaning of vessel walls and maintaining material flow in many industrial applications. While there are many different configurations of air cannons, the principle of operation for all air cannons is the same. A large volume of air is exhausted in a short period of time through a access port in the vessel wall, creating a powerful burst of air which dislodges particulate material that has adhered to the internal wall of the vessel. The various configurations of air cannons are generally differentiated based on their air discharge velocity and the design of the inlet seal for the associated air reservoir. However, each of the various air cannon configurations in use utilize a separate air reservoir as part of an air cannon attached to the particular vessel access port. This configuration poses many problems to those in the affected industries.
The first concerns the installation costs associated with independently mounted air cannons. For each air cannon in the system, a separate air reservoir incurs the added cost of purchasing and maintaining the reservoir as well as installation costs associated with routing the necessary air lines to charge each reservoir and additional wiring activate the individual air cannons. In some instances, attempts to avoid these installation costs have been made whereby an air cannon assembly is moved from access port to access port to clean the respective areas of the vessel. While saving on installation costs, this practice incurs its own costs in that an employee is required to reposition the air cannon to a desired access port.
A second concern is the space requirements for installing and operating individual air cannons with an integrated air reservoir. Traditional air cannons with their individual air reservoirs require a substantial amount of space to install and once installed they present an obstacle for the operators working around the particular vessel.
Third, the typical air cannon is mounted in close proximity to the vessel, and most are mounted directly to the vessel. Usually the processes within the vessel generate a substantial amount of heat and considerable particulate debris. In these harsh environments, traditional air cannons frequently experience premature wear and failure of internal components, particularly in its valve assemblies.
In many instances the valves used to control the flow of air from the reservoir require the maintenance of a pressure differential within the valve body. In order to maintain this pressure differential within acceptable tolerances, the rate at which the reservoir may be charged is restricted such that subsequent firing of the cannon is delayed considerably. Moreover, because the restriction in the reservoir's charging rate, exacerbates the deleterious effects of any leaks which may be present in the system.

SUMMARY OF THE INVENTION

The air cannon manifold of the present invention addresses these problems in the industry by providing an air cannon manifold that permits a plurality of access ports to be serviced by a single air reservoir, providing a reliable cost effective solution to the aforementioned problems. First, it reduces installation costs by eliminating the requirement for a separate air reservoir at each air cannon portal. By eliminating the requirement for a separate air reservoir, additional savings are realized at initial installation by eliminating the requirement to install a separate air line to charge each separate air reservoir.
Second, by eliminating the requirement for an individual air reservoir at each air access port, the initial space requirements may be reduced for new installations employing the air cannon manifold of the present invention. Similarly, modification of existing installations to incorporate the air cannon manifold will permit reclamation of valuable work space previously occupied by the individual air reservoirs servicing the existing air cannon ports. In both instances, obstructions in close proximity to the vessel are eliminated, permitting workers around the vessel a safer work environment.
Third, the air cannon manifold of the present invention further permits the working components of the system, such as its valves and sensors, to be positioned away from the high temperatures and debris generated by the vessel, resulting in improved reliability and extending the service life of the components and the system.
Finally, the air cannon manifold of the present invention enables rapid charging of the reservoir to permit a single reservoir to service a plurality of cleaning ports or to permit successive firing into any selected cleaning port.

BRIEF DESCRIPTION OF THE DRAWINGS

The system and methodology of the present invention are depicted in the accompanying drawings which form a portion of this disclosure and wherein:
FIG. 1 is a perspective view of an air cannon manifold and an air reservoir;
FIG. 2 is a side view of an air cannon manifold;
FIG. 3 is a perspective view of the air cannon manifold from an input side, with an actuator removed to show an exhaust actuator bore;
FIG. 4 is a partial sectional view of an exhaust valve;
FIG. 5 is a partial sectional view of an inlet valve;
FIG. 6 is a partial sectional view of an inlet valve and exhaust valve in their open position;
FIG. 7 is a schematic diagram for sequentially selecting an exhaust port to be serviced by the air cannon manifold; and
FIG. 8 is a schematic diagram for monitoring and signaling alarm conditions of the air cannon manifold.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawings for a clearer understanding of the invention, it may be seen that a preferred embodiment of the invention contemplates a single air reservoir 11, providing a high volume pressurized air source for an air cannon system, connected to the air cannon manifold 10 via an inlet duct 12 attached to an inlet port 20. A plurality of exhaust ducts 13 interconnect exhaust ports 30 of the air cannon manifold 10 with the access ports of an industrial vessel, such as a kiln and its associated structures.
The air cannon manifold 10 may be seen in greater detail in FIGS. 2-6. As depicted, air cannon manifold 10 comprises a housing 14, defining a plenum therein. An inlet port 20 extends through a first wall 15 in housing 14 and receives high volume pressurized air from a source such as a pressurized air reservoir 11 via an inlet duct 12, such as the elbow connector shown in the drawings. Inlet duct 12 may be a pipe or similar conduit and may be bolted to manifold 10 through a flange 17, or any suitable attachment means. An inlet valve 21 is provided to control the flow of air from reservoir 11 to manifold housing 14 by selectively opening and closing inlet port 20.
In the embodiment shown, inlet valve 21 is best seen in FIGS. 5 and 6, and comprises an inlet valve actuator 22, such as a pneumatic cylinder or the like attached to second wall 16 of manifold housing 14 an adapter plate 18 and opposing inlet port 20. An inlet actuator shaft 23, is extensible through an inlet actuator bore 24 defined in the second wall 16 of manifold housing 14 and closed by plate 18. An inlet valve seal 25 is attached to a distal end of inlet actuator shaft 23, and is selectively positioned by inlet valve actuator 22 for sealing engagement with an inlet seat 26, defined on an interior face of first wall 15. Preferably inlet actuator bore 24 will be dimensioned to be larger than inlet valve seal 25, to facilitate removal of inlet valve 21 for servicing or replacing this component.
Air cannon manifold 10 further defines a plurality of exhaust ports 30 in a second wall 16 of housing 14. Exhaust ducts 13 are connected to exhaust ports 30 to communicate the high volume air released into the manifold 10 to a corresponding access port in vessel. Exhaust ducts 13 may be a pipe or similar conduit and may be bolted to manifold 10 through an exhaust flange 18, or any suitable attachment means. An exhaust valve 31 is provided for each exhaust port 30 to control the flow of air delivered by manifold 10 to a desired access port in vessel serviced by the air cannon. Exhaust valves 31 are selectively positionable to open and close their associated exhaust ports 30. As best depicted in FIGS. 4 and 6, exhaust valves 31 comprise an exhaust valve actuator 32, such as a pneumatic cylinder, attached to housing first wall 15 and opposing their respective exhaust ports 30. An exhaust actuator shaft 33, is extensible through an exhaust actuator bore 34 defined through first wall 15. Exhaust valve seals 35 are attached to the distal ends of exhaust actuator shafts 33 and are selectively urged against exhaust port seats 36 by exhaust valve actuators 32. As with the inlet valve 21, exhaust actuator bore 34 is preferably dimensioned to be larger than exhaust valve seal 35 to facilitate removal of exhaust valves 31 for servicing or removal of these components. A protective ring 43 may also be attached to an inner surface of first wall 15 coaxial with actuator bore 34, and extending inwardly therefrom, such that upon opening of exhaust valve 31, exhaust valve seal 35 may be retracted into ring 43 to avoid exposure to the high velocity air experienced within housing 14 upon opening inlet valve 21. Each exhaust valve 31 is independently controllable to permit selective routing of the air blast to a desired access port in the vessel to clean the respective areas of the vessel walls based on the vessel's operating conditions.
We have found a preferred configuration for inlet seal 25 and exhaust seals 35. According to our preferred embodiment, shown in FIGS. 4 and 6, seals 25 and 35 comprise a disk portion 41, extending from and coaxial with a chamfered disk portion 42. Cylindrical disk portion 41 has a diameter smaller than that of the inner diameter of the respective inlet port 20 or exhaust port 30 to facilitate positive alignment of the seals 25, 35 in the respective ports 20, 30. The chamfered disk portion 42 has a diameter greater than disk portion 41, and provides for sealing engagement with the respective valve seat 26, 36. More preferably, chamfered portion 42 is made of a resilient material to improve its sealing engagement as it is urged against the valve seat 26,36.
Our preferred embodiment inlet actuator 22 and exhaust actuator 32 are mounted with their operative mechanisms external to manifold housing 14. This arrangement provides the advantage of permitting ready access to the actuators 22, 32 for routine inspection, maintenance and servicing. This arrangement also provides an advantage in that the positioning of the operative mechanisms avoids exposure to the large pressure differentials encountered within manifold housing 14 during cannon firing sequences.
Having thus described an exemplar of our air cannon manifold, its preferred method of operation will be described. A typical single duty cycle, for the air cannon manifold comprises the steps of sealing inlet port 20, charging the air reservoir 11 with air from a pressurized air source, opening a desired exhaust port 30, and opening inlet port 20 to permit venting of the pressurized air form reservoir 11 to the desired access port on the vessel to be cleaned. This process may be controlled either manually or automatically. A schematic diagram for a controller 50 directing sequential firing of a three port air cannon manifold is shown in FIG. 7.
As may be seen in FIG. 7, the sequential firing cycle is initiated at II, which initiates an air reservoir 11 charging cycle, B02 through Q6, and exhaust port 1 activation cycle, B09 through Q2. The exhaust port 1 activation cycle delays opening of a first exhaust valve 30 (normally closed) for sufficient time to permit completion of the air reservoir 11 charging cycle. It should be noted that by maintaining the exhaust valves 30 in the normally closed position we can significantly reduce the deleterious effects of any back draft from the vessel that may carry particulates or high temperature air into manifold housing 14. Once sufficient time has elapsed to charge air reservoir 11, the first exhaust valve 30 is activated and is held open for a sufficient duration to permit completion of the inlet valve firing sequence, B04 through Q1. Upon activation of the inlet valve firing sequence, inlet valve 20 is opened, permitting the rapid venting of the pressurized air in air reservoir 11 through air cannon manifold 10, first exhaust port 30 and its associated exhaust duct 13, to the desired access port on the vessel to be cleaned. Completion of the first exhaust valve 30 activation sequence Q2, resets the air reservoir charging sequence and initiates activation of the cycle for a second exhaust port 30, which proceeds in like manner to that described for the first exhaust port cycle. It varies from the first exhaust port cycle in that signal Q3 resets the first exhaust port cycle so that first exhaust valve 30 is maintained in a closed position. A third exhaust port 30 is activated in like manner and restarts the sequenced firing cycle.
We have found that when a pneumatic actuator is used for the inlet valve actuator 22 and that actuator is reliant on the same air source that is used to charge reservoir 11 it is desirable that the charging of reservoir 11 be delayed while inlet valve 21 is being closed to ensure that sufficient pressure is available to reliably activate inlet valve actuator 22 for sealing inlet port 20. This may be accomplished by temporarily closing a valve to block the communication of the pressurized air source to reservoir 11 for sufficient time to permit the closure of inlet valve 21. The temporary interruption of airflow to reservoir 11 also facilitates alignment of inlet valve seal 25 as residual air flow through inlet port may cause misalignment of inlet valve seal 25.
Automatic control of the air cannon manifold 10 may also be provided by monitoring process specific variables, such as temperature, oxygen content, or the like, that would indicate particulate accumulation at any particular location within the process vessel. In this circumstance, the blast cannon manifold controller 50 would be specifically targeted to remedy particulate accumulations based on the indications of the particular process specific variable, thereby improving the efficiency and efficacy of the blast cannon system in maintaining the cleanliness of the process vessel.
In addition, as shown in FIG. 8, the blast manifold controller 50 may also provide notification of user determined alarm conditions within the air cannon manifold 10 or air cannon system or vessel process that may potentially impact the safety or efficiency of the process for which the air cannon is employed.
It is to be understood that the form of the invention as shown herein is a preferred embodiment thereof and that various changes and that modifications may be made therein without departing from the spirit of the invention's scope as defined in the following claims.

Claims

1. An air cannon manifold comprising a housing defining a plenum therein, an inlet port defined in a wall of said housing, said inlet port receiving a pressurized fluid source in communication with said inlet port, an inlet valve selectively positionable to open and close said inlet port, a plurality of exhaust ports defined in said wall of said housing, and a plurality of exhaust valves selectively positionable to open and close said exhaust ports, whereby said pressurized fluid may be communicated via said exhaust ports and exhausted to a selected access port in a vessel to be cleaned of deposits.

2. The air cannon manifold of claim 1 wherein said housing is substantially boxlike.

3. The air cannon manifold of claim 1, wherein said housing is substantially spherical.

4. The air cannon manifold of claim 1 wherein said inlet valve further comprises an inlet valve actuator attached to said housing, said inlet valve actuator having an extensible inlet actuator shaft, and an inlet valve seal attached to a distal end of said actuator shaft, wherein said inlet actuator shaft urges said inlet valve seal in sealing engagement with said inlet port.

5. The air cannon manifold of claim 4 wherein said inlet valve actuator is attached to an external wall of said housing, and said inlet actuator shaft is extensible through an inlet actuator bore defined in said housing.

6. The air cannon manifold of claim 4, wherein said inlet valve seal further comprises a disk portion, extending from and coaxial with a chamfered disk portion, said disk portion having a diameter smaller than said chamfered disk portion.

7. The air cannon manifold of claim 6, wherein said disk portion has a diameter les than an inner diameter of said inlet port.

8. The air cannon manifold of claim 7, wherein an outer surface of said chamfered disk portion is comprised of a resilient material.

9. The air cannon manifold of claim 1 wherein said exhaust valve further comprises an exhaust valve actuator attached to said housing, said exhaust valve actuator having an extensible exhaust actuator shaft, and an exhaust valve seal attached to a distal end of said actuator shaft, wherein said exhaust actuator shaft urges said exhaust valve seal in sealing engagement with said exhaust port.

10. The air cannon manifold of claim 9 wherein said exhaust valve actuator is attached to an external wall of said housing, and said exhaust actuator shaft is extensible through an exhaust actuator bore defined in said housing.

11. The air cannon manifold of claim 9, wherein said exhaust valve seal further comprises a disk portion, extending from and coaxial with a chamfered disk portion, said disk portion having a diameter smaller than said chamfered disk portion.

12. The air cannon manifold of claim 11, wherein said disk portion has a diameter less than an inner diameter of said exhaust port.

13. The air cannon manifold of claim 11, wherein an outer surface of said chamfered disk portion is comprised of a resilient material.

14. The air cannon manifold of claim 1 further comprising a controller, wherein said controller provides a signal to said inlet valve and said exhaust valve and said inlet valve and exhaust valve are selectively positionable responsive to said signals.

15. The air cannon manifold of claim 14, wherein said controller provides said signal at timed intervals.

16. The air cannon manifold of claim 14, wherein said controller provides said signal responsive to a process variable.

17. A method of controlling an air cannon manifold associated with a kiln, said air cannon manifold comprising a housing defining a plenum therein, an inlet port defined in a wall of said housing, said inlet port receiving a high volume pressurized fluid from a reservoir communicating with said inlet port, an inlet valve selectively positionable to open and close said inlet port, a plurality of exhaust ports defined in said wall of said housing, and a plurality of exhaust valves selectively positionable to open and close said exhaust ports, said method comprising the steps of:

a. closing said inlet valve to seal said inlet port,

b. charging said reservoir with a high volume of pressurized fluid,

c. opening an exhaust valve of a selected exhaust port,

d. opening said inlet valve to vent a portion of said high volume pressurized fluid from said reservoir through said air cannon manifold.

18. The process of claim 17, further comprising the step of interrupting fluid flow to said reservoir while closing said inlet valve.

19. The process of claim 17, wherein the step of closing said inlet valve further comprises signaling said inlet valve to maintain said seal for a specified time.

20. The process of claim 17, wherein the step of opening an exhaust valve, further comprises signaling said exhaust valve to remain open for a specified time.

21. The process of claim 17, wherein the step of opening said inlet valve further comprises signaling said inlet valve to close after a specified time.

22. A method of controlling an air cannon manifold associated with an industrial apparatus having a plurality of access ports for cleaning said apparatus by use of pressurized fluid, said air cannon manifold comprising a housing defining a plenum therein, an inlet port defined in a wall of said housing, said inlet port receiving a high volume pressurized fluid from a reservoir communicating with said inlet port, an inlet valve selectively positionable to open and close said inlet port, a plurality of exhaust ports defined in said wall of said housing in fluid communication with said access ports, and a plurality of exhaust valves mounted to said manifold and selectively positionable to open and close said exhaust ports, said method comprising the steps of:

a. closing said inlet valve to seal said inlet port,

b. charging said reservoir with a high volume of pressurized fluid,

c. opening an exhaust valve of a selected one of said plurality of exhaust ports,

d. opening said inlet valve to vent a portion of said high volume pressurized fluid from said reservoir through said air cannon manifold, and,

e. iteratively repeating said sequence to vent said pressurized fluid through additional selected ones of said plurality of exhaust ports.

23. The method as defined in claim 22 wherein said plurality of exhaust ports are normally closed during charging of said reservoir.

24. The method as defined in claim 22 wherein said each of said plurality of exhaust ports are sequentially individually opened during subsequent iterations to provide cleaning to different regions of said industrial apparatus.

25. The method as defined in claims 22 wherein said industrial apparatus is monitored for conditions indicating desirability of fluid cleaning and said monitoring is used to selectively open said exhaust ports.