Pilot Valve Actuator With Differential Gearing for Fail-Safe Adjustment
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Solution Overview
Problem
Existing remote adjustment systems for gas regulators in gas distribution networks face challenges in maintaining accuracy and system life due to the addition of pneumatic chambers, require significant energy storage for fail-safe mechanisms, and struggle to meet intrinsically safe classifications, especially in explosive environments.
Innovation Solution
The use of a differential gear arrangement that allows either electric motor to drive the actuator shaft, eliminating the need for energy storage and high-energy components, and providing a fail-to-known position feature without latching or braking mechanisms, ensuring safe and reliable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a pneumatic bias chamber is added to enable remote adjustment, then remote adjustment capability is improved, but regulator performance deteriorates and system complexity increases
Solution Approach 1:
The patent replaces the traditional mechanical fixed stop system with an electric motor-driven actuator system. The actuator uses a differential gear mechanism driven by electric motors to position the pilot valve stop, eliminating the need for pneumatic bias chambers and associated solenoid valves. This substitution maintains remote adjustment capability while preserving regulator performance and reducing system complexity.
2Reliability
If energy storage spring is used for fail-to-known position feature, then fail-safe capability is improved, but device complexity and energy requirements increase
Solution Approach 1:
The patent replaces mechanical spring-based fail-safe mechanisms with an electric motor-based system. The actuator incorporates a differential gear mechanism where one motor serves as the primary drive and the other motor provides fail-safe functionality. This eliminates the need for energy storage springs, locking devices, and complex mechanical fail-safe mechanisms while maintaining the fail-to-known position capability.
3Reliability
If high energy components are used for fail-safe mechanism, then reliability is improved, but intrinsically safe classification becomes difficult
Solution Approach 1:
The patent replaces high-energy mechanical components with low-energy electric motor components. The differential gear mechanism uses two electric motors where the second motor can drive the mechanism to a known position if the first motor fails. Electric motors inherently store less energy than springs or electromagnetic locking devices, making the system more suitable for intrinsically safe classification in explosive environments while maintaining fail-safe functionality.
4Measurement precision
If latching or braking arrangement is used to control motor drive, then control precision is improved, but device complexity increases
Solution Approach 1:
The patent replaces latching or braking arrangements with a differential gear mechanism controlled by two electric motors. The control system uses software logic to determine which motor should be active based on the desired valve position and system state. This eliminates the need for mechanical latching or braking components while maintaining precise control through electronic control of motor activation and torque management.
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 enables remote and accurate adjustment of gas regulator set points while ensuring system longevity and compliance with safety standards, including intrinsically safe classifications, by allowing either motor to operate the actuator without additional safety mechanisms, thus preventing unwanted energy release or ignition risks.
Implementation Method 1
a differential gear arrangement (3) configured to drive the actuator drive shaft (18) when one of the drive electric motor (1) or the emergency electric motor (5) is powered to provide a drive torque
Data Source
Figure 1~2a
Figure 2b~2c
Figure 2d~2e
AI summary
An actuator for adjusting a pilot valve in a gas supply regulator, the actuator comprising a drive electric motor configured to provide rotational movement to a first drive shaft, an emergency electric motor configured to provide rotational movement to a second drive shaft, a differential gear arrangement coupled to the first drive shaft and coupled to the second drive shaft and configured to generate rotational movement of an actuator drive shaft from the rotational movement provided by one of the first drive shaft and the second drive shaft, and a rotary to linear device coupled to the actuator drive shaft and configured to convert rotational movement of the actuator drive shaft into a linear movement for adjusting the pressure valve. The differential gear arrangement is configured to drive the actuator drive shaft when one of the drive electric motor or the emergency electric motor is powered to provide a drive torque to one of the first drive shaft or the second drive shaft and the other of the drive electric motor and the emergency electric motor unpowered. By configuring a back drive torque of each of the drive electric motor and the emergency electric motor with respect to a resistive torque of the actuator drive shaft and the drive torques provided by the drive electric motor and the emergency electric motor, the drive electric motor and the emergency electric motor can be permanently connected to the actuator drive shaft through the differential gear arrangement, which obviates a requirement for a latching or braking arrangement.