Drilling Riser Latch System Preventing Inadvertent Disconnection
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Solution Overview
Problem
Existing methods for securing drilling riser joints in deep water offshore operations are inefficient, as they rely on friction which may not be sufficient to maintain connection, leading to potential disconnection during wave movement and are time-consuming and hazardous for personnel.
Innovation Solution
A mechanical latch system with a cantilevered arm and toothed profiles is introduced to secure the cam ring in place, preventing inadvertent disconnection by engaging with a moveable ring, ensuring the drilling riser joints remain connected during operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If friction is used to maintain cam ring position, then the connection process is simple, but the reliability is insufficient and disconnection may occur during wave movement
Solution Approach 1:
A latch mechanism is introduced as an intermediary component between the cam ring and the box end to provide additional securing. The latch includes a arm that engages with a toothed profile on the cam ring, preventing axial movement and ensuring reliable connection during wave movement while maintaining the friction-based simplicity of the original design.
Solution Approach 2:
The latch system provides beforehand protection by pre-establishing a mechanical interlock before wave movement occurs. The toothed profile engagement acts as a preventive measure against disconnection, cushioning against the potential harmful effect of wave-induced separation without requiring complex active control systems.
2Productivity
If bolts or screws are used to connect riser joints, then the connection strength is high, but the assembly process is time-consuming and hazardous
Solution Approach 1:
The cam ring with toothed profile engages automatically with the latch mechanism during the stabbing operation, providing self-securing without requiring separate bolt or screw fastening operations. This eliminates the time-consuming and hazardous manual fastening process while maintaining secure connection through the mechanical interlock.
Solution Approach 2:
The traditional bolt/screw mechanical fastening system is replaced with a cam ring and latch mechanism that uses cam action and toothed profile engagement. This substitution eliminates the need for wrenches and manual fastening operations, significantly improving assembly speed while maintaining connection security through the engineered mechanical interlock.
3Ease of operation
If cam ring and dogs are used to secure riser joints, then no bolts or screws are needed, but friction may not be sufficient to maintain connection
Solution Approach 1:
The latch mechanism serves as an intermediary that enhances the friction-based connection by adding a mechanical interlock. The toothed profile on the cam ring engages with the latch arm, providing additional stability and preventing disconnection while maintaining the simplicity of the cam ring operation.
Solution Approach 2:
The system changes the connection parameter from pure friction to friction plus mechanical interlock. By introducing the toothed profile engagement, the connection stability is enhanced without changing the operational simplicity of the cam ring axial movement.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The mechanical latch system enhances the reliability and safety of drilling riser connections by preventing accidental disconnection and reducing the risk of injury and time consumption in assembly, while maintaining the joints securely in place even under wave-induced movement.
Implementation Method 1
the toothed profile on the latch engages the toothed profile on the moveable ring. The engagement of the toothed profile on the latch with the toothed profile on the moveable ring obstructs axial movement of the moveable ring
Implementation Method 2
Friction between the dogs and the cam ring maintains the cam ring positioned to drive the dogs against the pin end of the adjoining drilling riser joint
Data Source
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AI summary
A technique for securing drilling riser joints (30) in a drilling riser string (20) is presented. The drilling riser joints (30) have a tubular housing (34) that has a box configuration (38) on one end and a pin configuration (40) on the other end. The drilling riser string (20) is assembled by connecting the pin end (40) of one drilling riser joint (30) to the box end (38) of an adjoining drilling riser joint (30). A moveable ring (46) is used to connect adjoining drilling riser joints (30). The moveable ring (46) is used to drive a fastener, such as a dog (70), of one drilling riser joint (30) against the adjoining drilling riser joint (30). The moveable ring (46) is driven axially from a first position, where the fastener (70) is not engaged against the adjoining drilling riser joint (30), to a second position where the fastener (70) is engaged against the adjoining drilling riser joint (30). A latch (48) is used to prevent the moveable ring (46) from moving inadvertently from the second position. This prevents the drilling riser joints (30) from disconnecting inadvertently.