Rotating Control Device Latching for Fast Seal Assembly Replacement
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Solution Overview
Problem
Conventional rotating control devices in drilling operations suffer from mechanical wear, high maintenance costs, and downtime due to failure of bearing assemblies and mechanical clamping mechanisms, posing safety risks and increasing environmental risks when pressure control is lost.
Innovation Solution
An improved rotating control device with a simplified design featuring hydraulically-actuated, fail-last-position latching assemblies and indirectly mounted tapered-thrust bearings, which reduces wear and allows for quick installation, removal, and replacement of seal and bearing assemblies, along with a unique seal carrier design for precise preload management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional mechanical clamping mechanisms and bearing assemblies are used in rotating control devices, then the device can maintain structural integrity and secure the seal assembly, but mechanical wear occurs leading to high maintenance costs and downtime
Solution Approach 1:
The seal and bearing assembly is designed as a separable, modular unit that can be independently removed from the bowl housing. The latching assembly secures this modular unit, allowing the entire seal and bearing assembly to be quickly removed and replaced as one unit without disassembling individual components, thereby reducing maintenance downtime while maintaining pressure control reliability through secure latching
Solution Approach 2:
The patent replaces conventional mechanical clamping mechanisms with a hydraulic latching system. Hydraulically-actuated pistons drive latching dogs that engage with the seal and bearing assembly, providing secure retention without the sliding contact and mechanical wear associated with traditional mechanical clamps, thus extending component life and reducing maintenance requirements
2Device complexity
If directly mounted bearings are used in the seal assembly, then the structure is simpler, but mechanical wear increases and component life decreases
Solution Approach 1:
The bearings are extracted from direct mounting on the bowl housing and instead mounted on the seal and bearing assembly itself. This separation allows the bearings to be part of the removable modular unit, eliminating continuous sliding contact with the housing and reducing mechanical wear, thereby extending component life while maintaining structural simplicity through standardized mounting interfaces
Solution Approach 2:
The latching assembly provides secure retention of the seal and bearing assembly before operational stresses occur. By firmly securing the assembly with hydraulically-actuated latching dogs that engage precision-machined grooves, the system prevents premature failure from misalignment or loosening, cushioning against operational stresses that would otherwise accelerate wear and extend component life
3Reliability
If complex latching mechanisms are used to secure the seal assembly, then the security and reliability improve, but the device complexity and maintenance requirements increase
Solution Approach 1:
The latching assembly serves multiple functions: it secures the seal and bearing assembly to the bowl housing, provides a means for quick release during maintenance, and ensures proper positioning through engaged grooves. This multi-functionality achieves high reliability and secure retention while avoiding the need for separate complex mechanisms for each function, thereby reducing overall device complexity
Solution Approach 2:
The latching mechanism uses hydraulically-actuated pistons to drive the latching dogs, replacing complex mechanical linkages with a simpler hydraulic actuation system. This provides reliable and secure engagement through hydraulic force while reducing mechanical complexity, as the hydraulic system can be controlled from the drill string without requiring complex external control mechanisms
4Productivity
If the seal and bearing assembly is designed for quick removal and replacement, then maintenance downtime is reduced, but the structural integrity and security during operation may be compromised
Solution Approach 1:
The latching assembly is pre-configured with hydraulically-actuated pistons and engagement grooves that ensure proper alignment and secure retention before operation begins. The pistons are positioned to automatically engage the latching dogs with the grooves when the assembly is installed, providing immediate secure retention without requiring additional alignment or securing steps, thus maintaining both quick removal capability and operational security
Solution Approach 2:
The latching dogs and engagement grooves are designed with asymmetric geometries that provide secure retention in the engaged position while allowing easy release when the hydraulic actuation is reversed. The asymmetric design ensures that the latching mechanism maintains strong engagement during operation but can be quickly released by reversing the hydraulic pressure, achieving both security and maintenance efficiency
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 solution reduces non-productive downtime, extends the life of seal and bearing assemblies, and enhances safety by ensuring stable pressure control, even when hydraulic power is lost, while lowering maintenance costs and environmental risks.
Implementation Method 1
A plurality of hydraulically-actuated fail-last-position latching assemblies are disposed about an outer surface of the bowl housing to controllably extend a plurality of piston-driven dogs radially into a groove of the seal and bearing assembly
Implementation Method 2
a plurality of tapered-thrust bearings indirectly mounted to the seal and bearing housing to facilitate rotation of the mandrel
Implementation Method 3
a first interference-fit sealing element attached to a bottom distal end of the mandrel
Data Source
AI summary
A rotating control device includes a bowl housing with an inner aperture to receive a seal and bearing assembly. A plurality of hydraulically-actuated fail-last-position latching assemblies are disposed about an outer surface of the bowl housing to controllably extend a plurality of piston-driven dogs radially into a groove of the seal and bearing assembly. The seal and bearing assembly includes a housing, a mandrel disposed within an inner aperture of the housing, a first interference-fit sealing element attached to a bottom distal end of the mandrel, a plurality of tapered-thrust bearings indirectly mounted to the housing, a preload spacer disposed between top and bottom tapered-thrust bearings, a plurality of jam nuts to adjust a preload of the tapered-thrust bearings and a lower seal carrier attached to the seal and bearing housing comprising a plurality of dynamic sealing elements that contact the mandrel.