Underwater flange installation is a critical step in underwater pipeline connections, requiring special construction methods and measures to ensure quality and safety. Below are detailed steps and precautions for underwater flange installation:
Preparation
Confirm installation location and environmental conditions: Understand the challenges and risks of underwater operations, select an appropriate installation site, ensure the site is level and stable, and convenient for operation and maintenance.
Select Flange Type and Specification: Determine the connection method and sealing requirements based on engineering needs, and select the appropriate flange type and specification.
Prepare installation tools and materials: including wrenches, screwdrivers, washers, lubricants, etc., to ensure a safe and smooth installation process.
II. Installation Steps
Flange Alignment and Fastening: Determine the installation position of the flange underwater and secure it using clamps, ropes, and other tools. Ensure the flange is perpendicular to the pipe axis and the flange face is parallel to the pipe axis.
Flange Joining: Align two flanges and temporarily secure them with bolts. During the joining process, pay attention to the alignment of the sealing faces and bolt holes to ensure sealing performance and connection strength.
Bolt Tensioning: Use an appropriate wrench or torque wrench to gradually tighten bolts in accordance with the specified sequence and torque requirements. Pay attention to even tension distribution to avoid over-tightening or under-tightening.
Seal Inspection: After bolt tightening is completed, perform a seal inspection. Methods such as hydrostatic testing or gas leak detection can be used to check for any leakage at the flange connection. If leakage is detected, adjustments and repairs should be made promptly.
Secure after ensuring the sealing performance and connection strength meet the requirements. Utilize tools such as lock washers or locking agents to increase the bolt tension, preventing the flange connection from loosening.
Section 3: Precautions
Safety Rules: Underwater flange installation is a high-risk operation and must strictly adhere to safety operating procedures. Workers should wear appropriate protective gear, maintain good communication with the command personnel, and ensure the safety of the operation process.
Environmental Adaptation: Underwater operation environments are complex and variable, and appropriate installation methods and tools should be selected based on the actual situation. In harsh conditions such as strong currents and low visibility, corresponding safety measures should be taken to ensure stability and accuracy of the operations.
Quality Control: The quality of the flange installation is directly related to the safety and service life of the project. Therefore, during the installation process, operations should be strictly conducted according to the design requirements and technical specifications to ensure that the sealing performance and connection strength of the flange joints meet the requirements.
Inspection and Maintenance: After installation, regular inspections and maintenance of the flange connections are required. The inspection includes the tightness of the bolts and the wear of the sealing surfaces. Any issues should be addressed and repaired promptly to ensure the normal operation of the flange connections.
IV. Construction Method
Submerged flange installation generally follows a pre-fabrication method, which involves dividing the pipeline into sections on land and then connecting the flanges at suitable locations before submerging the assembled pipeline into water. This approach reduces the time and difficulty of underwater operations, enhancing installation quality and efficiency.
In summary, underwater flange installation is a critical component of underwater pipeline connections, requiring special construction methods and measures, adherence to certain steps and precautions, to ensure installation quality and safety.
