Return Exhaust Assembly With Misalignment-Tolerant Fluid Bypass
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Solution Overview
Problem
Existing reverse circulation hammers require precise alignment of components to prevent heat checking and failure, which limits their operational flexibility and efficiency, especially in varying ground conditions.
Innovation Solution
A return exhaust assembly with a resilient coupling between the return tube and exhaust sleeve allows for axial misalignment, featuring an annular gap for fluid bypass, enabling adjustable fluid flow to control striking force and reduce the risk of clogging, and incorporating a choke ring for variable fluid distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If precision alignment of return tube and exhaust sleeve is required, then heat checking of piston is prevented, but operational flexibility and adaptability to varying ground conditions are reduced
Solution Approach 1:
The exhaust sleeve is designed to be movable relative to the return tube, allowing dynamic adjustment of the alignment during operation. This enables the system to adapt to varying ground conditions while maintaining reliable piston operation through controlled movement rather than fixed precision alignment.
Solution Approach 2:
The system allows changes in the positional parameters of the exhaust sleeve relative to the return tube. By enabling movement within certain limits, the alignment parameters can be adjusted to accommodate different operating conditions while preventing piston heat checking through controlled parameter variation.
2Power
If fixed fluid flow path is used, then piston striking force is maximized, but ability to control fluid flow for different ground conditions is lost
Solution Approach 1:
The fluid flow path is made dynamic through the movable exhaust sleeve that can shift position to open or close off the bypass passage. This allows the system to dynamically adjust fluid flow distribution between the piston and bypass based on ground conditions, controlling both power delivery and adaptability.
Solution Approach 2:
The bypass passage acts as an intermediary flow path that can be selectively opened or closed. By introducing this intermediate channel controlled by the movable exhaust sleeve, the system can regulate fluid flow to balance piston power with bit-face clearance requirements for different ground conditions.
3Stability of the object's composition
If return tube is rigidly fixed, then structural stability is maintained, but ability to accommodate misalignment and float between bearing surfaces is eliminated
Solution Approach 1:
The connection between the return tube and exhaust sleeve is designed to be dynamically adjustable rather than rigidly fixed. This allows the exhaust sleeve to move and float between bearing surfaces to accommodate misalignment while maintaining structural stability during normal operation through controlled movement.
Solution Approach 2:
The coupling between the return tube and exhaust sleeve incorporates flexible elements that allow controlled movement and misalignment accommodation. This flexible connection enables the exhaust sleeve to float and adjust position while maintaining sufficient structural stability for reliable operation.
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
This design enhances operational flexibility, reduces the risk of component failure, and maintains efficient drilling performance by allowing adjustable fluid flow and power control, minimizing bit-face plugging and maintaining reliable production.
Implementation Method 1
an exhaust sleeve having a section seated and resiliently supported on the seat
Implementation Method 2
The annular gap or passage forms a fluid bypass enabling an operator to vary or control the amount of fluid otherwise used for driving a piston of the RC hammer to bypass the piston
Data Source
AI summary
A return exhaust assembly 50 for a reverse circulation hammer H comprises return tube 52 having first and second ends and a seat 56 at or near the first end 54. An exhaust sleeve 58 has: a section 60 seated and resiliently supported on the seat 56; and, a portion 62 that extends to and includes an end 64 of the exhaust sleeve 58 distal the section 60. The portion 60 surrounds a length of the return tube 52 with an annular clearance 66 formed between the return tube 52 and the sleeve 58 from a down hole end of the seat 56 to the distal end 64 of the exhaust sleeve 58. This arrangement allows relative movement, and therefore a degree of misalignment between the exhaust sleeve 58 and the return tube.