Vibrating Extraction Device for Nuclear Thermocouples
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Solution Overview
Problem
The extraction and insertion of thermocouples in pressurized water nuclear reactors are hindered by high friction forces and the risk of damage, especially when the blocking part is located at a considerable distance from the extraction point, leading to stuck thermocouples and difficulties in replacing them without causing conduit damage.
Innovation Solution
A device with a clamping and vibrating assembly, comprising a sealed casing with a clamp and adjustable pneumatic vibrator, and an accelerometer for measuring vibrations, allows for remote operation to determine and apply optimal vibration for reducing friction during extraction or insertion of elongated elements, such as thermocouples, by adjusting the clamp and vibrator to facilitate axial traction or thrust.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If strong traction is exerted on the thermocouple to ensure extraction, then the thermocouple can be pulled out from the conduit, but the conduit wall may be damaged and the operation becomes difficult
Solution Approach 1:
The patent applies mechanical vibration to the thermocouple during extraction by generating ultrasonic vibrations that propagate along the thermocouple length. This vibration reduces the friction coefficient between the thermocouple and conduit wall, allowing extraction with much lower traction forces and preventing conduit damage while maintaining high extraction success rate
2Ease of operation
If the blocking part is located at a considerable distance from the extraction point, then the thermocouple is stuck in the conduit, but applying vibration from the far end becomes inefficient
Solution Approach 1:
The patent applies preliminary action by generating vibrations at the accessible end of the thermocouple before extraction begins. The vibration source is activated first to propagate vibrations along the entire thermocouple length, softening the friction conditions throughout the conduit, and then traction is applied. This preliminary vibration treatment makes extraction feasible even when the blocking part is far from the extraction point
3Device complexity
If simple traction is applied to the thermocouple, then the operation is simple, but the friction forces are very high and extraction may fail
Solution Approach 1:
The patent integrates a vibration generation device with the traction device, adding vibrational motion to the simple traction operation. The vibration component reduces friction forces along the thermocouple-conduit interface, enabling successful extraction without significantly increasing operational complexity, thus maintaining ease of use while dramatically improving extraction success rate
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 method effectively reduces friction and increases the chances of successful extraction and insertion of thermocouples, minimizing the risk of damage to the conduit and ensuring reliable temperature measurement by optimizing vibration levels during the process.
Implementation Method 1
a vibrator (49) arranged in said sealed casing (41) and making it possible to vibrate said sealed casing (41) and said clamp (43) in which case the device also comprises a means (50) for remotely measuring the vibration generated by the vibrator (49) on the duct (21)
Implementation Method 2
a means (50) for remotely measuring the vibration generated by the vibrator (49) on the duct (21) to determine the optimum vibration
Implementation Method 3
The vibrations thus created in the duct (21) of the thermocouple (22) to be extracted during the traction phase make it possible to create micro-separations between the thermocouple and the duct and to generate a reduction in the coefficient of friction between said thermocouple and said duct
Data Source
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AI summary
The invention relates to a device for assisting in the underwater extraction or insertion of an elongate element disposed in a pipe and to a method for assisting in the extraction or insertion of one such element. The device includes a clamping and vibration-generating assembly (40) comprising: (i) a sealed housing (41, 42) bearing a gripper (43) and including a member for tightening the gripper (43) on the pipe, an adjustable vibrator for vibrating the housing (41, 42) and the gripper (43), and a member for measuring the vibration produced by the vibrator on the pipe in order to determine the optimum vibration; and (ii) means for remotely controlling the gripper (43) and the vibrator.