Pressure Pulsation Attenuation in Rotary Cone Rock Bit Seals
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Solution Overview
Problem
The pressure pulsation caused by cone pumping in roller cone rock bits leads to detrimental effects on the sealing system, including lubricant leakage and contamination, due to the flow of grease along various paths, which reduces seal life and operational efficiency.
Innovation Solution
A lubricant cone pumping pressure restrictor system comprising an annular gland and a pressure restricting ring is positioned between the radial thrust bearing system and the lubricant sealing system to attenuate cone pumping pressure pulsation, intercepting and restricting the flow of grease before it reaches the sealing system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sealing system is provided to retain lubricant within the bearing system, then lubricant retention is improved, but pressure pulsation from cone pumping causes detrimental effects on the sealing system including lubricant leakage and contamination
Solution Approach 1:
A pressure restrictor system comprising a restrictor member positioned within an opening in the cone is introduced as an intermediary element between the bearing system and the sealing system. This restrictor member attenuates pressure pulsation generated by cone pumping before the pulsation can reach and damage the sealing system, thereby protecting the seal while maintaining lubricant retention.
Solution Approach 2:
The opening in the cone is segmented into two distinct regions: a first region that provides fluid communication between the bearing system and the sealing system for normal lubricant flow, and a second region that provides fluid communication between the bearing system and the exterior for pressure relief. The restrictor member is positioned within the first region to selectively attenuate pressure pulsation while allowing normal lubricant circulation.
2Productivity
If the cone pumping pressure pulsation is allowed to act on the sealing system, then the sealing system can maintain its structure, but lubricant leakage and contamination occur reducing operational efficiency
Solution Approach 1:
The pressure restrictor system acts as an intermediary that selectively attenuates pressure pulsation while allowing normal lubricant flow through the first region. This protects the sealing system from pressure-induced leakage and contamination, maintaining lubricant integrity and operational efficiency without restricting necessary lubricant circulation.
3Reliability
If a pressure restrictor system is added to attenuate pressure pulsation, then seal life is enhanced, but device complexity increases
Solution Approach 1:
The opening in the cone is divided into two functional regions: a first region for normal lubricant flow that contains the restrictor member, and a second region for pressure relief to the exterior. This segmentation allows the pressure restrictor system to be integrated into the existing cone structure without adding significant complexity, as the restrictor member utilizes the pre-existing opening geometry.
Solution Approach 2:
The opening in the cone serves multiple functions: it provides fluid communication between bearing and seal systems, accommodates the pressure restrictor system for pulsation attenuation, and includes a second region for pressure relief to the exterior. This multi-functionality reduces the need for separate components, thereby limiting the increase in device complexity.
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 pressure restrictor system effectively reduces the impact of pressure pulsation on the sealing system, enhancing seal life and maintaining lubricant retention within the bearing system, thereby improving the operational reliability and longevity of the rock bit.
Implementation Method 1
A lubricant cone pumping pressure restrictor system comprising an annular gland and a pressure restricting ring is positioned between the radial thrust bearing system and the lubricant sealing system to attenuate cone pumping pressure pulsation
Implementation Method 2
intercepting and restricting the flow of grease before it reaches the sealing system
Data Source
AI summary
A drill tool comprises includes a bit body, at least one bearing shaft extending from the bit body and a cone mounted for rotation on the bearing shaft. The bearing system for the tool includes a radial thrust bearing from which cone pumping pressure pulsation originates. A lubricant sealing system including an annular seal gland and a seal ring retained within the annular seal gland functions to retain lubricant in the bearing system. The tool further includes a lubricant cone pumping pressure restrictor system formed by an annular gland (separate from the annular seal gland) and a pressure restricting ring retained within the annular gland. The lubricant cone pumping pressure restrictor system is positioned between the radial thrust bearing system and the lubricant sealing system and is adapted to attenuate cone pumping lubricant pressure pulsation from acting on the seal ring retained within the annular seal gland.