Pipes and tubular conduits – With flow regulators and/or baffles
Reexamination Certificate
1999-07-26
2001-01-09
Brinson, Patrick (Department: 3752)
Pipes and tubular conduits
With flow regulators and/or baffles
C138S039000, C181S212000, C181S251000, C181S268000
Reexamination Certificate
active
06170528
ABSTRACT:
FIELD OF THE INVENTION
The field of the invention is an assembly of orifice chambers progressively reducing operating pressure of large gas flows having at least one orifice plate in each orifice chamber to take small progressive pressure drops across each orifice plate in lieu of one large pressure drop for reducing wear on each orifice plate and the overall noise.
BACKGROUND OF THE INVENTION
Present orifice chambers utilize an assembly of a number of orifice chambers having orifice plates to progressively reduce the operating pressure of large gas flows, typically flue gas operating from 20 to 40 psig at temperatures ranging from 500 to 1500° F., to atmospheric pressure. Each orifice chamber is equipped with one or more orifices or perforated plates, and typically the assembly has a minimum of two and a maximum of seven orifice chambers having orifice plates in order to progressively take small pressure drops across the orifice plates in each of the orifice chambers in lieu of one large pressure drop. The size of the orifice chambers ranges typically from 30 inches in diameter to 130 inches in diameter. The flowing medium is typically flue gas from a catalytic cracking unit going to the stack outlet of a refinery. The flue gas is a result of the combustion process in a regenerator of a catalytic cracking unit.
The orifice or perforated plates of the orifice chambers require periodic inspection and maintenance and therefore are equipped with a manway or manhole for access to each orifice chamber and the orifice plates or plates secured therein for inspection and maintenance such as repair or replacement, which requires opening and closing each manway or manhole, is time consuming and expensive.
In the following prior art, U.S. Pat. No. 3,712,502 discloses a tanker having internal compartments formed by internal sections
2
which may be welded therein and having openings
10
therethrough; U.S. Pat. No. 3,050,315 discloses a tank having spaced perforated surge plates
4
mounted therein; U.S. Pat. No. 4,611,724 discloses a fluid storage tank with internal welded baffles
20
and perforations to permit fluid to flow through the baffles; U.S. Pat. No. 5,346,092 discloses a tank having welded interior separators
13
,
14
and one manhole
12
secured to an inner tank section; U.S. Pat. No. 2,092,490 discloses a welding of interior separating plate
22
within a tank.
The following U.S. Pat. Nos. 710,405, 1,613,746, 1,952,867, 3,250,319, 3,338,238, and 3,425,810 disclose various arrangements for mounting welded interior sections or providing perforations within the sections all within larger chambers.
None of the foregoing prior art orifice chambers and patents disclose or suggest an assembly of orifice chambers for a gradual, progressive, and sequential reduction of operating gas pressures as it flows through a plurality of orifice chambers having removable orifice plates in the orifice chambers and a single access manway or manhole to a first orifice chamber, and access to successive chambers is provided by sequential removal of the orifice plates for maintenance, such as for inspection, repair, and replacement.
It would be highly desirable to provide an improvement in the present assemblies of such orifice chambers which would require only one manway or manhole for the entire assembly for maintenance such as inspection, repair, and replacement of the orifice or perforated plates.
SUMMARY OF THE INVENTION
The present invention is directed to such an improved assembly of orifice chambers for progressive and gradual reduction of operating pressure of gas flow therethrough which requires only one manway or manhole for maintenance, such as inspection, repair, and replacement of the orifice or perforated plates.
The foregoing is accomplished by an assembly of orifice chambers for the progressive and gradual reduction of operating pressures of gas flow such as by flue gas from a catalytic cracking unit to the stack outlet of a refinery, which comprises a body having a flowway, inlet and outlet for the gas to flow through, a plurality of orifice plate supports secured to and extending partially into the flowway spaced from one another in a direction of the gas flow, orifice plates releasably secured to and supported by the support plates thereby forming the orifice chambers, the orifice plates being provided with one or more orifices or perforations effective to provide progressive gradual pressure drops in the gas flow, and a manhole or manway having a releasable closure in the body upstream from the first of the orifice plates so that upon removal of the first of the orifice plates access is provided to the next successive plate, and removal of the next orifice plate provides access to the next successive plate and so on for maintenance, such as inspection, repair, and replacement of each of the orifice plates in the assembly of orifice chambers. Preferably, the orifice plates are secured to an internal annular shell secured to the body by an annular ring providing an annular space between the internal shell and the body allowing for thermal expansion and contraction. Preferably, the orifice plates are releasably secured to the orifice plate supports by fillet welding and can be replaced by fillet welding. Sound dampening or thermal insulation or both can be utilized.
Accordingly, it is an object of the present invention to provide an assembly of orifice chambers having a flowway therethrough for the progressive and gradual reduction of operating pressure of large gas flows through the flowway as previously described in which only a single access manway or manhole for maintenance, such as inspection, repair, and replacement of the orifice plates in the orifice chambers of the assembly is required.
A further object of the invention is the provision of an improved assembly of orifice chambers for the progressive and gradual reduction of operating pressures of gas flow therethrough, each having a removable orifice plate which when removed provides a manway or manhole for access to the next orifice plate for maintenance, such as inspection, repairs, and replacement so that only one manway or manhole is necessary for access for maintenance of each of the orifice chambers of the assembly.
It is a further object of the invention to provide such an improved assembly of orifice chambers which permits thermal expansion and contraction caused by gases flowing through its flowway.
Other and further objects, features, and advantages of the present invention will be apparent from the following description of presently preferred embodiments of the invention taken in conjunction with the accompanying drawings in which the like reference numerals designate like parts throughout several views.
REFERENCES:
patent: 737443 (1908-08-01), Mooers
patent: 2682395 (1954-06-01), Calridge et al.
patent: 3016972 (1962-01-01), Dugas
patent: 4130173 (1978-12-01), Cooksey
patent: 4142413 (1979-03-01), Bellinga
Brinson Patrick
Tapco International Inc.
Weiler James F.
LandOfFree
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