Static structures (e.g. – buildings) – Compound curve structure
Reexamination Certificate
2000-09-21
2001-12-04
Friedman, Carl D. (Department: 3635)
Static structures (e.g., buildings)
Compound curve structure
C052S082000, C052S083000, C403S217000, C403S218000
Reexamination Certificate
active
06324792
ABSTRACT:
FIELD OF THE INVENTION
This invention pertains to covered clarifiers, and more particularly, the present invention pertains to a low profile retractable cover which is supported largely on the outside wall of a circular clarifier.
BACKGROUND OF THE INVENTION
The clarification of industrial effluent is normally effected by alternatively agitating and letting the effluent settle, and lifting floating scum from the surface of the effluent or scraping sediments at the bottom of the reservoir. The clarification process is often accompanied by a fermenting action and a generation of odorous bio-gases, and/or the release of volatile organic carbons. For environmental reasons, these gases must be collected and treated. Therefore, a clarification reservoir, or clarifier, is preferably covered and sealed to contain the off-gases. Also, a clarifier preferably has a piping system to transport the off-gases to a gas treatment plant.
An industrial clarifier is often circular in shape. The reservoir typically has a central column supporting a motor, a gearbox, and a bearing assembly carrying a surface-skimming boom, a bottom rake or both. These equipment must be accessible for inspection, repair or preventive maintenance. Therefore a first preferred feature of a clarifier cover consists in its ability to be opened, to inspect, repair or maintain the boom, the rake, the circumferential launder or other equipment inside the reservoir. A second preferred feature is that the cover must be adaptable to the integration of a catwalk to the central column, to allow access to the machinery on the central column at all times.
The covering of a clarifier is often associated with the implementation of environmental regulations. Therefore a cover is often installed on an existing clarifier which was not designed to support a cover structure. Therefore, the retrofit installation of a cover over an existing clarifier must be done in such a way that the cover does not apply a substantial load or side stress on the central column inside the clarifier.
Another preferred feature in a clarifier cover is that the enclosed volume above the level of the clarifier must be kept as small as possible to maintain the ventilation of the clarifier as efficient and as economically as possible.
Examples of various systems available for covering a reservoir are described in the following documents:
U.S. Pat. No. 3,130,488 issued on Apr. 28, 1964 to G. Lindström;
U.S. Pat. No. 3,683,427 issued on Aug. 15, 1972 to H. C. Burkholz et al.;
U.S. Pat. No. 4,136,408 issued on Jan. 30, 1979 to E. L. Dahlbeck et al.;
U.S. Pat. No. 4,400,927 issued on Aug. 30, 1983 to A. M. Wolde-Tinase;
U.S. Pat. No. 4,951,327 issued on Aug. 28, 1990 to V. J. Del Gorio, Sr.;
U.S. Pat. No. 5,381,634 issued on Jan. 17, 1995 to S. Pietrogrande et al;
U.S. Pat. No. 5,943,709 issued on Aug. 31, 1999 to H. Y. Chiu;
Although the cover structures of the prior art deserve undeniable merits, it is believed that a need still exists in the industry for a clarifier cover which has a low profile, which does not apply substantial load on the central column of a clarifier, which is easily openable for inspection, repair or maintenance of the equipment inside the clarifier and which is strong and durable and can accommodate a catwalk to the central column.
SUMMARY OF THE INVENTION
In the present invention, there is provided a retractable clarifier cover which has a low profile, which is particularly appropriate for a retrofit installation over an existing clarifier, and which has all the other aforesaid advantages.
In a first aspect of the present invention, there is provided a clarifier cover having a plurality of saddle brackets mounted on the circular outside wall of the clarifier and a central ring plate mounted on the central column of the clarifier. A support structure is affixed to the saddle brackets and to the central ring plate, and a flexible sheet cover is affixed to the support structure. The support structure has a shape defined by a low profile circular segment of revolution around the central ring plate.
The shape of the support structure is particularly advantageous for defining a relatively small volume of gas under the cover, whereby the ventilation of the clarifier is doable economically. The shape of the support structure is also advantageous for isolating the mechanical and electrical equipment that may be present atop the central column of the clarifier from the corrosive or inflammable gases which may be generated inside the clarifier by the content of the clarifier.
In accordance with another aspect of the present invention, there is provided a support structure for supporting a flexible sheet cover over a circular clarifier. The support structure comprises a plurality of spaced-apart saddle brackets disposed in a first circular array defining a first circle. There is also provided a plurality of ring trusses disposed in a second circular array and defining a second circle, concentric with and inside the first circle. The support structure also comprises a radial array of outer trusses each having an outside end mounted to one of the saddle brackets and an inside end mounted to the plurality of ring trusses. A series of inner trusses are individually affixed to and extend from the inside end of one of the outer trusses, toward the centre of the first circle.
In this structural arrangement, the outer trusses and the ring trusses constitute a self-supporting structure wherein the weight thereof rests on the saddle brackets. The inner trusses are affixed to the outer trusses in an overhung mode such that the loading applied to the central column of a clarifier by the cover structure is minimal or negligible.
In yet another aspect of the present invention, there is provided a retractable cover mounted over a circular clarifier. The retractable cover comprises a central ring plate mounted on the central column of the clarifier; a plurality of saddle brackets affixed to the outside wall of the clarifier, and a support structure affixed to the support brackets and to the central ring plate. The support structure is made of an array of triangular frame sectors, each having an apex over the central column and a base over the outside wall of the clarifier, and a flexible sheet sector affixed thereto. At least one of the flexible sheet sectors has a retractable section near the base of the corresponding triangular frame sector. This retractable section is removably affixed to one of the triangular frame sector and to the clarifier wall. The clarifier cover according to the present invention is thereby selectively openable for inspection, repair or maintenance of equipment inside the clarifier.
Other advantages and novel features of the present invention will become apparent from the following detailed description.
REFERENCES:
patent: 481347 (1892-08-01), Cunningham
patent: 2360285 (1944-10-01), Sherman
patent: 3130488 (1964-04-01), Lindstrom
patent: 3377637 (1968-04-01), Zamorano
patent: 3683427 (1972-08-01), Burkholz
patent: 3894367 (1975-07-01), Yacoboni
patent: 4136408 (1979-01-01), Dahlbeck
patent: 4256300 (1981-03-01), Boucher
patent: 4400927 (1983-08-01), Wolde-Tinase
patent: 4413747 (1983-11-01), Tenold
patent: 4593710 (1986-06-01), Stafford
patent: 4750509 (1988-06-01), Kim
patent: 4951327 (1990-08-01), Del Gorio, Sr.
patent: 5381634 (1995-01-01), Pietrogrande
patent: 5943709 (1999-08-01), Chiu
Friedman Carl D.
Nguyen Chi
Theriault Mario
LandOfFree
Circular clarifier with retractable cover does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Circular clarifier with retractable cover, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Circular clarifier with retractable cover will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2600698