Variable Size Inner Tube Head Assembly for Core Drilling
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Solution Overview
Problem
Current core barrel assemblies for core drilling operations have small clearances between the outer diameter of the tool and the inner diameter of the drill string, leading to low fluid flow and slow rates of ascent and descent, which prolongs the time required to transport the inner tube head assembly and overshot to the bottom of the drill string, thereby reducing core production efficiency.
Innovation Solution
The inner tube head assembly is designed with a variable size configuration, featuring a first standardized size for the latch casing, spindle, and inner tube cap assembly, and a second standardized size for the landing shoulder and inner tube cap adapter, creating larger clearance gaps to enhance fluid flow while maintaining structural integrity, allowing for faster descent and ascent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the inner tube head assembly is formed to engage with a particular standard size of drill string, then the assembly maintains structural integrity and proper engagement, but the clearance between the outer diameter of the tool and the inner diameter of the drill string becomes small, resulting in low fluid flow and slow rates of ascent and descent
Solution Approach 1:
The inner tube head assembly is divided into multiple components (latch casing, latch body, spindle, inner tube cap assembly, landing shoulder, inner tube cap adapter) that can be independently sized. This segmentation allows different parts to have different dimensions, enabling optimization of both engagement and fluid flow characteristics
Solution Approach 2:
Different portions of the inner tube head assembly are given different sizes. The latch casing, spindle, and inner tube cap assembly are formed to a first standardized size, while the landing shoulder and inner tube cap adapter are formed to a second standardized size. This local differentiation creates larger clearance gaps in specific areas to enhance fluid flow while maintaining proper engagement in other areas
2Reliability
If the clearance between the tool and drill string is reduced to improve engagement, then the assembly is more securely locked, but the fluid flow around and through the tool is reduced, prolonging transportation time
Solution Approach 1:
By segmenting the assembly into multiple independently sized components, the design can optimize engagement security in certain areas while maintaining larger clearance gaps in other areas to reduce transportation time
Solution Approach 2:
The landing shoulder and inner tube cap adapter are formed to a larger second standardized size compared to the first standardized size of other components. This creates larger clearance gaps in specific locations to enhance fluid flow and reduce transportation time while maintaining secure engagement through the properly sized latch mechanisms
Data Source
AI summary
An inner tube head assembly for a core barrel assembly having a latch casing coupled to a latch body, a landing shoulder coupled to the latch body and a spindle, and an inner tube cap assembly coupled between the spindle and an inner tube cap adapter. The landing shoulder and the inner tube cap adapter are a first size. The latch casing, the latch body, the spindle, and the inner tube cap assembly are a second size. The inner tube head assembly includes latches configured to work with the inner tube head assembly of the first size and the drill string of the second size. The first size is larger than the second size. The inner tube head assembly engages a drill string sized to cooperate with the first size. A core drilling system is also described.