Blowout Preventer Ram Seal Pressure Control
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Solution Overview
Problem
The high pressures in blowout preventer ram seals, especially at 20,000 p.s.i., lead to excessive stress and potential failure of resilient materials, while the pressure energizing characteristic necessary for lower pressures is compromised due to the natural geometry of the rams, resulting in ultra-high pressures that can cause seal failure.
Innovation Solution
A method to regulate the maximum pressure in blowout preventer ram seals by using a pressure release piston and springs to limit the pressure in the front seal to a predetermined value, preventing ultra-high pressures and maintaining the necessary pressure energizing characteristic at lower pressures, allowing the rams to come together face-to-face and prevent high pressure generation within the ram seals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the blowout preventer stack working pressure is increased to 20,000 p.s.i., then the pressure control capability is improved, but the stress on the resilient seals becomes excessively high causing potential failure
Solution Approach 1:
The patent divides the seal system into two distinct sealing interfaces: a primary seal between the ram and bore, and a secondary seal between the ram and piston. This segmentation allows each seal to be optimized for different pressure conditions, with the primary seal handling normal operating pressures and the secondary seal preventing ultra-high pressure generation at the ram face.
Solution Approach 2:
The patent introduces a piston as an intermediary element between the ram and the high-pressure fluid. This piston acts as a pressure mediator that prevents the direct transmission of ultra-high pressures to the ram face seals, while still allowing the ram to exert sealing force on the primary seal through controlled pressure transmission to the piston rod.
2Adaptability or versatility
If the natural geometry of the blowout preventer rams is used, then the pressure energizing characteristic is maintained at lower pressures, but ultra-high pressures are generated in the front seal causing failure
Solution Approach 1:
The patent makes the sealing system dynamic by allowing the piston to move relative to the ram body. The piston can be positioned at different locations along the ram travel path, creating variable sealing geometries. This dynamic adjustment allows the system to maintain pressure energizing characteristics at low pressures while preventing ultra-high pressure generation at the ram face during high-pressure operations.
Solution Approach 2:
The patent changes the pressure distribution parameters within the sealing system by introducing the piston. This creates a dual-pressure-zone system where the pressure behind the ram can be maintained for sealing purposes while the pressure at the ram face is limited, effectively decoupling the pressure parameters that previously were directly coupled through the natural ram geometry.
3Stress or pressure
If higher working pressure components are used, then the pressure control capability is improved, but the equipment becomes heavier and taller
Solution Approach 1:
The patent employs resilient seals (flexible elements) to provide the primary sealing function rather than relying entirely on heavy metallic sealing structures. These flexible seals can accommodate pressure variations and maintain sealing effectiveness without requiring proportionally heavier components, thus improving the pressure-to-weight ratio of the blowout preventer system.
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 solution effectively limits the pressure in the seals to a safe level, preventing material failure and maintaining seal integrity by ensuring the rams can operate efficiently at higher pressures without generating excessive stress, thus enhancing the reliability of the blowout preventer system.
Implementation Method 1
A method to regulate the maximum pressure in blowout preventer ram seals by using a pressure release piston and springs to limit the pressure in the front seal to a predetermined value
Implementation Method 2
using a pressure release piston and springs to limit the pressure in the front seal
Data Source
AI summary
The method of preventing pressures higher than a predetermined pressure in the front ram seals of blowout preventer rams comprising providing blowout preventer rams suitable for sealing across the bore of a blowout preventer stack, providing seals on the blowout preventer rams which sealingly isolate the bore area below or upstream of the blowout preventer rams from the area above or downstream of the blowout preventer rams, providing a passageway from the front to the rear of the blowout preventer rams to vent the upstream or higher pressures to the rear of the blowout preventer rams, and communicating the resilient seal material in the front ram seals with a pressure release piston which will relieve the pressure at the predetermined pressure.