Bi-directional Servo Valve Seal System for Dirty Fluids
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Solution Overview
Problem
Flow modulating devices (FMDs) used in drilling operations with 'dirty' fluids containing particulates face jamming issues due to particulate contamination, leading to unreliable sealing and signal clarity problems, as existing seals are not effective in bi-directional operation under high pressure and particulate presence.
Innovation Solution
A hydraulically actuated servo valve with a seal system featuring upper and lower outer seals acting as wipers or scrapers to prevent particulates from reaching inner seals, maintaining low friction and high pressure sealing capabilities, even in the presence of 'dirty' fluids, by dynamically applying pressure on both sides of the seal system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If single seal design is used in dirty fluids, then device complexity is reduced, but reliability deteriorates due to particulate contamination and jamming
Solution Approach 1:
The seal system is divided into multiple functional segments: outer seals that act as wipers to remove particulates, and inner seals that provide the primary sealing function. This segmentation allows each seal type to specialize in its specific function, with outer seals handling contamination and inner seals maintaining sealing integrity, thereby resolving the contradiction between simplicity and reliability.
Solution Approach 2:
Outer seals serve as intermediary elements between the dirty fluid environment and the inner seals. These outer seals wipe away particulates and prevent them from reaching the inner seals, acting as a protective mediator that shields the critical sealing surfaces from contamination while maintaining overall system reliability.
2Adaptability or versatility
If seals operate bi-directionally in dirty fluids under high pressure, then adaptability is improved, but manufacturing precision deteriorates due to particulate contamination
Solution Approach 1:
The bi-directional seal system is segmented into upper and lower outer seals with corresponding upper and lower inner seals. Each pair operates independently in its respective direction, with outer seals wiping particulates away from inner seals during both upward and downward movements. This segmented approach maintains manufacturing precision of seal contact areas by preventing particulate contamination while enabling full bi-directional adaptability.
Solution Approach 2:
Before the inner seals make contact with the shaft in bi-directional operation, the outer seals perform preliminary wiping action to remove particulates from the seal surfaces. This preliminary cleaning action prevents contamination of the precision seal contact areas during both upward and downward movements, maintaining manufacturing precision while enabling adaptable bi-directional operation.
3Power
If high pressure is applied to both sides of seal during seating in dirty fluid, then power is improved, but object-affected harmful factors worsen due to particulate compaction and jamming
Solution Approach 1:
Outer seals act as intermediary protective elements that prevent high-pressure dirty fluid and compacted particulates from reaching the inner seals during seating operation. Even when high pressure is applied to both sides of the seal system, the outer seals maintain a clean interface for the inner seals, eliminating the harmful compaction effect while preserving the high sealing power needed for high-pressure applications.
Solution Approach 2:
The harmful particulates are extracted or removed from the sealing interface by the outer wiper seals before they can be compacted by high pressure. This extraction function separates the beneficial high sealing power from the harmful particulate contamination, allowing the system to operate effectively under high pressure in dirty fluid environments.
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 solution ensures reliable bi-directional operation and prevents particulate contamination, maintaining signal clarity and seal reliability across a wide pressure range, from vacuum to several thousand psi, while allowing for efficient fluid flow modulation and pulse generation.
Implementation Method 1
upper outer seal and a lower outer seal acting as wipers or scrapers prohibit particulates from entering near and around an upper inner seal and a lower inner seal
Implementation Method 2
when differential high pressure is simultaneously and dynamically applied to both sides of the seal system, low friction between the seal system and the shaft is continuously maintained
Data Source
AI summary
Disclosed is an apparatus, method and system comprising one or more devices capable of modulating fluid flow, the fluid being a liquid or a gas resulting in a pressure fluctuation in a fluid flowing within a flow channel, comprising: a flow modulating device that acts as a servo valve such that the device comprises a shaft and a moveable actuator that slides along the shaft, wherein the shaft and the actuator are positioned at any angle within a principal fluid flow channel such that the fluid flows through the principal fluid flow channel. The fluid flowing within the principal fluid flow channel is selectively reversible and the fluid is connected to both an inner pilot flow channel and the principal fluid flow channel wherein the flow modulating device includes a particulate barrier system having at least one seal system comprising an upper outer seal and a lower outer seal prohibiting fluid particulates from entering the inner pilot flow channel and also includes an upper inner seal and a lower inner seal that further prohibit residual particulates from reaching any mating surface between the shaft of the flow modulating device and the upper seal, the upper inner seal, the lower outer seal, and the lower inner seal. The particulate barrier system operates in a fluid flow field wherein the fluid can flow in any direction and utilizes a sealing system wherein an upper outer seal and a lower outer seal prohibit particulates from reaching the respective surfaces of an upper inner seal and lower inner seal of the flow modulating device. An upper inner seal and lower inner seal further prohibit residual particulates from reaching surfaces between the seal and that of the shaft of the flow modulating device.