Dual-Polymer Seal Assembly for Drill Bit Debris Exclusion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional seal assemblies in rotary drill bits are prone to reliability issues due to the susceptibility of secondary polymer rings to damage, such as tearing, which compromises the integrity of the metal face seal and reduces the overall performance of the drill bit.
Innovation Solution
The implementation of a seal assembly with a metal seal ring and two polymer rings, where the first polymer ring applies a primary force and the second polymer ring, with equal or greater cross-sectional area and hardness, applies a secondary force to enhance the seal's durability and prevent debris ingress, thereby improving the reliability of the drill bit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a secondary polymer ring with low Shore A hardness is used to provide backup force and stop ingress of matter, then the seal assembly can prevent debris ingress, but the secondary polymer ring is susceptible to damage such as tearing
Solution Approach 1:
The patent changes the material parameter (Shore A hardness) of the secondary polymer ring from low hardness to high hardness. This allows the ring to maintain its sealing function while being more resistant to damage and tearing, directly resolving the contradiction between preventing debris ingress and avoiding susceptibility to damage.
2Force
If the second polymer ring provides only a lesser secondary force (20-40% of total face load), then it effectively backs up the first polymer ring, but it reduces the overall reliability of the rotary drill bit
Solution Approach 1:
The patent changes the force contribution parameter of the second polymer ring from providing only 20-40% of total face load to providing a greater secondary force. This enhanced force contribution improves the backup support for the metal face seal, thereby increasing overall reliability while maintaining appropriate force distribution.
3Force
If the second polymer ring is made with low Shore A hardness to meet design requirements, then it can compress effectively to provide sealing force, but it becomes susceptible to tearing and damage
Solution Approach 1:
The patent changes the hardness parameter of the second polymer ring from low Shore A hardness to high Shore A hardness. This allows the ring to maintain effective sealing force while significantly improving its resistance to tearing and damage, resolving the contradiction between sealing effectiveness and structural strength.
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 configuration enhances the durability of the seal assembly, reducing the likelihood of damage and maintaining the seal's effectiveness, leading to improved reliability and performance of the rotary drill bit.
Implementation Method 1
A first polymer ring (also referred to as an energizer), when compressed, provides the primary force (or primary face load on the metal face seal)
Implementation Method 2
A second polymer ring, when compressed, provides a lesser secondary force (or lesser face load, such as 20-40% of the total face load)
Data Source
AI summary
An earth-boring rotary tool includes a body comprising a pin, a roller cone mounted on the pin, and a seal assembly disposed between the pin and the roller cone. The seal assembly includes a seal ring to form a seal between the seal ring and the roller cone. The seal assembly includes a first polymer ring, while compressed, applies a first force on the seal ring that biases the seal ring towards the roller cone. The seal assembly includes a second polymer ring proximate the first polymer ring. The second polymer ring, while compressed, applies a second force on the seal ring to further bias the seal ring towards the roller cone. The second force is greater than the first force.