Flow Meter Prover Piston Reset Mechanism
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Solution Overview
Problem
Conventional flow meter provers face issues with complex and space-consuming reset mechanisms that cause resistance and wear down components, and temperature measurement inaccuracies due to ambient exposure of temperature sensors.
Innovation Solution
A flow meter prover with a piston assembly and actuator assembly that uses a linear actuator and electromagnet to move the piston without resistance, and a photoelectric sensor system with flags to determine volume correction factors without disturbing the flag positions, along with a temperature sensor within a fluid-filled flag rod for accurate temperature measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional reset mechanisms (chain/belt with motor and clutch) are used to reset the piston, then the piston can be reset to starting position, but the mechanisms create resistance that hinders piston movement and causes incremental wear down of components
Solution Approach 1:
The patent extracts the reset function from the main flow measurement system by using a separate, isolated reset mechanism. The reset system uses a motor-driven reel that winds a cable to pull the piston back, completely separated from the fluid flow path. This extraction eliminates the resistance and wear problems caused by conventional chain/belt mechanisms that were directly in the piston's movement path.
Solution Approach 2:
The patent replaces the mechanical chain/belt and clutch system with an electrical motor-driven cable reel system. The motor controls the reel to wind or unwind the cable, providing smooth, resistance-free piston reset without the mechanical friction and wear inherent in chain/belt drives. The clutch is eliminated entirely, replaced by electrically controlled motor operation.
2Ease of operation
If conventional reset mechanisms with cross plate and sprockets are used, then the piston can be reset, but the mechanisms are complex and take up relatively large amounts of space
Solution Approach 1:
The complex cross plate, sprockets, and elliptical path mechanism are completely extracted and replaced with a simple motor-driven cable reel system. The cable runs along a straightforward path from the reel to the piston, eliminating the need for complex guiding structures, cross plates, and multiple rotating components.
Solution Approach 2:
The patent substitutes the entire mechanical linkage system (cross plate, sprockets, elliptical guides) with an electrical motor control system. The motor controls cable tension and piston position through electrical signals, dramatically reducing mechanical complexity and component count while maintaining reset functionality.
3Measurement precision
If optical eyes are mounted to a switch rod for detection points, then volume measurement can be performed, but when optical eyes need to be removed and replaced for maintenance, the volume must be recertified to ensure accuracy
Solution Approach 1:
The patent segments the detection system into two independent parts: the photoelectric sensors (detectors) mounted on the cylinder wall, and the flags mounted on the piston. The sensors remain fixed and calibrated, while only the flags need to be replaced during maintenance. This segmentation allows flag replacement without affecting sensor positioning or requiring volume recertification.
Solution Approach 2:
The patent uses flags as movable targets that pass by stationary photoelectric sensors. The flags are simple, replaceable components that carry the detection information, while the expensive and precision-critical photoelectric sensors remain fixed and unchanged. This copying approach allows maintenance of the flags without disturbing the calibrated sensor positions.
4Temperature
If temperature sensor is fixed to a thermo-well exposed to ambient air, then temperature measurement is possible, but the measurement is inaccurate because the sensor only measures temperature at one location and majority of thermo-well is exposed to ambient air
Solution Approach 1:
The patent nests the temperature sensor inside a borehole within the switch rod itself, placing the sensor deep within the rod's interior. This nested positioning ensures the sensor measures the actual rod temperature rather than ambient air temperature, as the sensor is surrounded by the rod material and measures its internal thermal state.
Solution Approach 2:
The patent introduces a thermal coupling medium (such as thermal compound or a metal insert) between the temperature sensor and the switch rod interior. This intermediary ensures efficient thermal contact between the sensor and the rod, allowing accurate measurement of the rod's temperature while isolating the sensor from ambient air exposure.
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 reduces component wear, simplifies maintenance, and provides accurate volume correction factors by decoupling the actuator during piston movement and using a fluid-filled flag rod to measure temperature, ensuring precise calculations without recertifying the known volume.
Implementation Method 1
The carriage includes an electromagnet that is operable to releasably couple to the piston assembly
Implementation Method 2
a photoelectric sensor mounted to the piston assembly adjacent the opening. The photoelectric sensor is operable to sense the first flag and the second flag
Implementation Method 3
A temperature sensor positioned within the hollow interior of the flag rod for measuring a temperature of the flag rod
Data Source
AI summary
A flow meter prover with a piston assembly that is movable from a start position to a finish position and an actuator assembly with a carriage that moves between a first position and a second position. Preferably, the carriage is operable to releasably couple to the piston assembly, and the carriage is operable to move the piston assembly from the finish position to the start position as the carriage moves from the second position to the first position. The actuator assembly preferably includes a linear actuator that moves the carriage, and the carriage preferably includes an electromagnet that releasably couples to the piston assembly. The piston assembly preferably slides on a flag rod having first and second flags mounted thereon and two guide rods. A photoelectric sensor senses the flags as the piston assembly slides on the flag rod and generates signals when it senses the flags.