Linear Power Modules for Crank Arm Valve Retrofit Without Emissions
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Solution Overview
Problem
The natural gas industry faces challenges in eliminating fugitive emissions from pneumatic and electro-pneumatic control systems, particularly in below and above ground applications where direct replacement of pneumatic actuators with electric or electro-hydraulic actuators is not feasible due to accessibility issues and the need for maintaining crank arm components.
Innovation Solution
The development of interchangeable linear power modules, including electric and electro-hydraulic actuators, which can replace pneumatic actuators in both above and below ground applications, ensuring zero emissions by connecting to existing crank arm mechanisms without sacrificing effectiveness or accuracy, and incorporating a pneumatic override for power failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If pneumatic actuators are used in control valve applications, then the system can operate with simple infrastructure, but fugitive natural gas emissions are generated continuously
Solution Approach 1:
The patent replaces pneumatic actuators with electric linear actuators, substituting a mechanical/pneumatic system with an electric system. This eliminates the use of natural gas in the actuation mechanism, thereby eliminating fugitive emissions while maintaining the ability to operate control valves in both above ground and below ground crank arm configurations.
Solution Approach 2:
The electric linear actuator is designed with universal adaptability to work with both above ground and below ground crank arm configurations. The actuator can be mounted in different locations and connected to various crank arm positions, providing multi-functional capability that replaces pneumatic actuators across diverse application scenarios.
2Object-generated harmful factors
If direct replacement of pneumatic actuators with electric actuators is attempted in below ground applications, then emissions are eliminated, but the valve stem is not accessible for direct connection
Solution Approach 1:
The patent transitions from direct axial connection (along the valve stem axis) to a perpendicular connection approach. The electric linear actuator is positioned perpendicular to the valve stem, with its piston rod connecting to the crank arm at a right angle. This dimensional change allows the actuator to be mounted in accessible locations above ground while still effectively operating below ground valves.
Solution Approach 2:
The crank arm serves as an intermediary mechanism between the electric linear actuator and the valve stem. The actuator connects to the crank arm, which then translates the linear motion into rotational motion to operate the valve. This intermediary approach allows the actuator to be positioned in accessible locations while maintaining control over the inaccessible valve stem.
3Object-generated harmful factors
If quarter turn electric and electro-hydraulic actuators are used, then emissions are eliminated, but they cannot be installed on below ground valves where the stem is inaccessible
Solution Approach 1:
Instead of adapting the valve to accommodate a quarter-turn actuator, the patent inverts the approach by using a linear actuator that operates perpendicular to the valve stem. The linear actuator's motion is translated through the crank arm mechanism to achieve the required rotational movement, making the system adaptable to below ground installations where the valve stem is inaccessible.
Solution Approach 2:
The patent employs a dynamic configuration where the electric linear actuator can be positioned and oriented to work with the crank arm mechanism. The system allows for adjustable mounting positions and angles, enabling the actuator to effectively operate valves in both above ground and below ground configurations, providing dynamic adaptability that quarter-turn actuators lack.
4Power
If pneumatic actuators are replaced with electro-hydraulic actuators, then emissions are eliminated and power is increased, but system complexity increases
Solution Approach 1:
The patent extracts the hydraulic component from the electro-hydraulic actuator system, using only the electric motor-driven linear actuator. This simplification removes the need for hydraulic fluid, reservoirs, pumps, and associated control systems, while still providing sufficient power for most control valve applications. The electric linear actuator delivers adequate torque and force without the complexity of a full hydraulic 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 allows for the elimination of fugitive natural gas emissions in all control valve applications, providing greater efficiency and flexibility by enabling the use of linear actuators that maintain the features of pneumatic actuators, while ensuring the system remains operational during power failures.
Implementation Method 1
interchangeable linear power modules, including electric and electro-hydraulic actuators
Implementation Method 2
the piston connected to a second end of the torque arm mechanism such that linear movement of the piston causes rotational movement of the first end of the torque arm mechanism
Data Source
AI summary
A system of interchangeable linear power modules for modulating crank arm actuators for above and below ground applications is disclosed. Electric and electro-hydraulic (E/H) actuators are used as direct replacement for pneumatic linear and quarter-turn actuators that utilize electro-pneumatic and pneumatic control instrumentation. For “below ground” and “above ground” control valve applications that utilize “crank arm” type actuators, existing pneumatic actuator may be replaced with a linear version of an electro-hydraulic or hydraulic actuator. This permits easy replacement of pneumatic actuator power modules with one of either electro-hydraulic or electric actuator power modules, thereby eliminating associated fugitive emissions.