Receptacles – Closures – Having means for securing or retaining closure in its closed...
Patent
1988-03-29
1989-07-25
Norton, Donald F.
Receptacles
Closures
Having means for securing or retaining closure in its closed...
220324, B65D 4516
Patent
active
048505056
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a device for clamping and locking of a cover against a flange in connection with subsea installations, particularly in connection with the production of oil and/or gas, and more particularly for clamping and locking of a housing cover against a flange on a valve housing for subsea pipelines. The clamping and locking device has comprehensive flexible locking segments when in an operating position mainly have the shape of a lying U with the opening turned in toward the middle of the cover, and which feature opposite facing contact and sealing surfaces for engagement with cover and flange.
TECHNICAL FIELD
A transportation pipeline for oil and/or gas represents a considerable volume which is subjected to pressure, and a possible blow-out can therefore be of long duration unless it can be shut off. In the event of a rupture of the transportation pipeline near a platform or other offshore installation, escaping gas and/or oil can be ignited. The result can be disastrous for human life as well as field economy.
Emergency shut-down equipment in the form of appropriate valves is therefore of vital importance.
The laying of pipelines at great depths normally takes place by welding together pipe joints to a pipeline on an installation vessel, after which the pipeline is continuously laid out from the aft side of the installation vessel over a ramp. Simultaneously, the installation vessel is towed or pulled forwards by means of tub-boats or by means of an anchor/winch system.
BACKGROUND ART
So far, installation of valves in the pipeline simultaneously with the laying of the pipeline has been difficult. This is mainly due to the weight and rigidity of the valves. An actuator is often mounted on top of the valves, and the installation of the valves on the seabed must therefore be closely monitored. The actuator on the valve housing cover cannot deviate many degrees from straight upright position before the function becomes problematic. These difficulties have in many cases contributed to the installation of the valve on the pipeline after the latter is installed on the seabed. The installation of the valve can take place by cutting off a piece of the pipeline and welding the valve into the resulting space.
Another procedure for the laying of pipelines consists of the insertion of a blind tube where a valve is desired to be mounted. This blind tube acts as a temporary joint to the other parts of the pipeline and must be of the same length as the valve to be inserted.
A known emergency shut-down valve will for a 20" pipeline have a length of approx. 6 meters and a weight of approx. 50-80 tons. Inspection, control and maintenance of such a valve must take place at certain intervals, and the inspection etc. will be endeavored to be executed without interruption of the production. A known method for implementation of this is that an internally displaceable telescopic tube is mounted in the valve housing area and is moved to isolate the valve housing from the pipeline. Thus, the valve chamber with check valve is shut off from the production pipe. Thereafter, the housing cover with check valve and actuator can be dismantled for inspection. Such an operation requires that the housing cover can be relatively easily and quickly released from the valve housing flange.
Mounting and possible dismantling must be feasible at great depths. It is therefore important that this work can be implemented in an easy, simple and quick way with a minimum risk of damage.
The state of the prior art moreover comprises U.S. Pat. Nos. 1,841,882 issued Jan. 19, 1932; 2,575,667 issued Nov. 20, 1951; 3,647,108 issued Mar. 7, 1972; and German Patent No. 1,245,235 issued July 20, 1967.
U.S. Pat. No. 1,841,882 relates to a hydraulic motor where the motor cylinder has a head or cover screwed on, designed with four locking segments similarly spaced around the circumference. Each of these locking segments are U-shaped where the facing contact and sealing surfaces are not parallel, but form an acute angle with each other
REFERENCES:
patent: 1841882 (1932-01-01), DeFrancisci
patent: 1871834 (1932-08-01), Astrom
patent: 2575667 (1951-11-01), Kr.phi.yer
patent: 3387738 (1968-06-01), Kemp
patent: 3647108 (1972-03-01), Kemp
patent: 3991902 (1976-11-01), Ford
patent: 4166549 (1979-09-01), Schultz et al.
patent: 4190074 (1980-02-01), Mailliet et al.
Den Norske Stats Oljeselskap A.S
Norton Donald F.
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