The whole underwater dry pipeline maintenance system mainly includes: underwater dry pressure maintenance operation cabin, deck hoisting recovery system, diving operation support system and pipeline maintenance equipment and tools in the cabin. Figure 15-28 is the schematic diagram of system operation.
I. Underwater dry maintenance cabin
(A) the overall design
According to the mission requirements, referring to the corresponding foreign system structure, the overall structure of the underwater dry cabin system refers to the SPAR/UWH integrated cabin form, and the base frame and cabin body are integrated. The dry cabin is installed in the pedestal, and its position can be adjusted in the pedestal to realize the fine adjustment and centering of the cabin pipe. Manipulators are installed at both ends of the base for pipeline lifting, centering and fixing. The system is equipped with advanced underwater monitoring, detection, positioning, control and display technology. The whole system includes the following subsystems: ① Underwater dry cabin structure system; (2) cabin positioning hydraulic system; ③ Underwater dry cabin power supply system; ④ Air supply and air supply system of underwater dry cabin; ⑤ Integrated monitoring system for underwater dry cabin; ⑥ Life support system in underwater dry cabin.
(2) High-pressure dry working cabin
The underwater dry-pressure maintenance operation cabin consists of the following systems: dry cabin base frame positioning and pipe hanging system, dry cabin moving system, pipe hanging system, life support system in the cabin, personnel transportation cabin and counterpart system, maintenance cabin hoisting and underwater positioning system, gas supply system, maintenance monitoring system, communication and information transmission system, etc.
Figure 15-28 System Operation Diagram
See figure 15-29 and figure 15-30 for the basic structural form of dry cabin.
Figure 15-29 Front view of dry cabin maintenance system
Figure 15-30 Side view of dry cabin maintenance system
The main research contents include: underwater dry operation cabin; Diving operation support system; Ground operation support system; Underwater positioning system; Submarine pipeline lifting system; Blockage of submarine pipeline; Submarine pipeline cutting equipment; Submarine pipeline centering adjustment system; Dry high pressure welding technology and equipment; Nondestructive testing technology and equipment; Treatment and recovery of pollutants and waste gas; Underwater monitoring and communication system; Automatic control and emergency support system.
1. Dry cabin structure
Dry cabin structure includes dry cabin shell, personnel access hatch, pipeline clamping device and sealing structure, cabin equipment and external protective structure. The main structural types and dimensions are: the main cabin is 3 ~ 6m long, 2.5~3.5m wide and 3 ~ 4m high, and the bulkhead is flat. The top of one end is provided with an entrance and exit butted with the personnel transport cabin, and the top of the dry cabin is provided with a plurality of watertight cabins. The lower part is open, and the centers of both ends are provided with clamping and sealing bayonets. The height from the center of bayonet to the baseline of dry cabin is about1.5m..
2. Personnel transport cabin (diving bell)
The main functions are as follows: ① Send the personnel engaged in underwater operations from the surface working mother ship to the underwater working cabin, and send the personnel back from the underwater working cabin to the surface working mother ship after completing relevant operations; (2) The maximum working depth is 60m, and 3 ~ 5 people are transported at a time; ③ The cabin can also be used to transport small equipment.
(3) Diving and life support system
See figure 15-3 1.
Figure 15-3 1 Main configuration of submersible system
Second, the sealing technology
The submarine pipeline with single-layer pipe structure adopts foreign pipeline plugging technology (integration), and the plugging technology of double airbag inflatable pipeline is also studied.
The double-tube structure submarine pipeline will learn from the foreign single-tube opening plugging technology and develop the double-tube annular space opening plugging technology to realize the practical application in dry cabin.
Three, underwater high pressure dry welding technology
At present, in the practical operation of submarine pipeline maintenance abroad, TIG welding system of high-pressure rail is mainly used for underwater dry welding, such as OOTO system of Aberdeen Submarine Ocean Co., Ltd., THOR- 1 system of Comex Company and IMT system of STATOIL Company.
This topic will learn from the mature underwater dry welding technology abroad, and develop the welding technology, special welding equipment and consumable materials for high-pressure TIG and high-pressure MMA welding.