Zero-Emission Explosion Proof Actuator Assembly
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Solution Overview
Problem
The oil and gas industry faces high costs due to the need for Class 1 Division 1 explosion-proof actuators that vent methane, which require multiple flame paths and critical surface tolerances, leading to increased manufacturing expenses and potential EPA fines.
Innovation Solution
A zero-emission explosion proof actuator assembly and servo system that meets Class 1 Division 1 requirements with a single flame path design, incorporating a hollow shaft rotor, threaded member, and integrated servo system, reducing manufacturing complexity and costs while eliminating methane venting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple flame paths and critical surface tolerances are implemented in Class 1 Division 1 actuators, then explosion-proof safety is improved, but manufacturing cost and complexity increase significantly
Solution Approach 1:
The actuator is divided into distinct zones: an explosion-proof zone containing only essential components (motor, rotor, shaft) and a non-explosion-proof zone containing the control electronics and servo system. This segmentation allows the explosion-proof portion to use simpler construction with fewer flame paths, while the non-explosion-proof portion can use complex electronics without compromising safety or requiring additional flame paths.
Solution Approach 2:
A flame arrestor or explosive atmosphere barrier is introduced as an intermediary component between the explosion-proof motor zone and the non-explosion-proof control zone. This barrier prevents flame propagation while allowing the system to meet explosion-proof requirements with simpler construction in each zone, reducing overall manufacturing complexity.
2Reliability
If two or more flame paths are required in the front end cap, then explosion-proof certification is achieved, but manufacturing precision requirements increase due to multiple critically dimensioned surfaces
Solution Approach 1:
The front end cap design is segmented into sections where only one surface requires critical dimensioning for the flame path, while other surfaces can use standard tolerances. The explosion-proof function is achieved through this single critically dimensioned surface combined with the segmented zone approach, eliminating the need for multiple tightly toleranced surfaces.
Solution Approach 2:
Instead of requiring multiple flame paths through the front end cap, the design inverts the approach by creating a single dominant flame path and using the segmented zone concept to achieve explosion-proof certification, thereby reducing the number of critically dimensioned surfaces from two or more to one.
3Stress or pressure
If pneumatic actuators are used to vent methane, then pressure relief is achieved, but gas revenue is lost and EPA fines increase
Solution Approach 1:
The traditional pneumatic venting system is replaced with an electric motor-driven actuator system that can precisely control valve positioning. This substitution eliminates the need to vent methane for pressure relief, allowing the valve to remain closed and retain gas revenue while preventing EPA violations through precise control and monitoring capabilities.
Data Source
AI summary
An explosion proof actuator assembly and servo system is described. Embodiments of the present invention include an explosion proof actuator assembly and servo system that may implement a rotating nut and a threaded member to effectuate an opening and closing of a valve.