Radiation-Shielded Pycnometer with Curved Ducts

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Solution Overview

Problem

Existing pycnometers face inaccuracies due to pressure sensors, measurement volume estimates, and dead volumes, especially when handling radioactive samples, as radiation damages sensors and alters gas pressure, leading to falsified measurements and inability to operate in shielded cells.

Innovation Solution

A pycnometer design with two communicating chambers and radiation-shielded pressure sensors, featuring an elbow conduit for sample chamber isolation, precise machining for reduced dead volumes, and a temperature sensor for correction, along with valves with sliding pistons and a volume variation device in the expansion chamber for improved precision and handling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If pressure sensors are placed directly in the sample chamber, then measurement is possible, but radiation damages the sensors and falsifies measurements

Engineering Contradiction:
Improvepressure measurement accuracyVSAvoidsensor durability under radiation
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent introduces an intermediary conduit system that transmits pressure information from the sample chamber to the pressure sensors without direct exposure. The pressure sensors are positioned in a protected location while still being able to measure the pressure in the sample chamber through the conduit, thus avoiding radiation damage while maintaining measurement capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent segments the pressure measurement function into separate components: the pressure sensing element is separated from the radiation-exposed sample chamber by conduits and shielding structures. This segmentation allows the sensitive pressure sensor to be isolated from radiation while still measuring the pressure conditions in the sample chamber.

Inventive Principle:
Principle #1Segmentation

2Reliability

If conventional pressure sensors are used in shielded cells, then radiation damage is avoided, but manipulations cannot be performed on samples

Engineering Contradiction:
Improvesensor protection from radiationVSAvoidsample manipulation capability
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent designs the pressure sensor assembly with multi-functionality: it serves both as a radiation-shielded measurement device and as a manipulation interface. The shielding structure and conduit system are configured to allow mechanical manipulation of samples through the same structure that protects the sensor, enabling both protection and operation capabilities.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If chambers are connected by external ducts, then communication between chambers is achieved, but dead volumes increase and measurement precision decreases

Engineering Contradiction:
Improvechamber communication capabilityVSAvoidvolume measurement accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent merges the chamber communication function directly into the block structure itself rather than using separate external ducts. The conduits are integrated within the block material, eliminating the need for additional external connecting components and thereby minimizing dead volumes while maintaining chamber communication capability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent extracts the dead volume problem by removing unnecessary external ducting and retaining only the essential minimum conduits within the block. By taking out the excessive external connections and keeping only the necessary internal pathways, the dead volumes are minimized while chamber communication is maintained.

Inventive Principle:
Principle #2Taking out (Extraction)

4Reliability

If radiation shielding is added around pressure sensors, then sensor protection is improved, but device complexity increases

Engineering Contradiction:
Improvesensor protection from radiationVSAvoidshielding structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the radiation shielding function with the existing block structure and conduit system. Rather than adding a separate shielding layer, the shielding is integrated into the block material and conduit configuration, combining multiple functions (structural support, pressure transmission, and radiation protection) into a single integrated design that reduces overall complexity.

Inventive Principle:
Principle #5Merging (Combining)

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 design enhances measurement accuracy and safety for radioactive samples by isolating sensors from radiation, minimizing dead volumes, and allowing precise temperature correction, enabling reliable volume and density determination without radiation damage.

Implementation Method 1

two pressure sensors 3 and 4 respectively associated with the chambers 1 and 2

Methodology Applied
Scientific EffectPressure measurement:

Implementation Method 2

there is a sample chamber temperature sensor

Methodology Applied
Scientific EffectTemperature measurement:

Implementation Method 3

the pressure sensors are mounted on the block, surrounded by radiation shielding

Methodology Applied
Scientific EffectRadiation shielding: Absorption (EM radiation)

Implementation Method 4

A partial expansion of the gas is then organized towards an expansion chamber which is made to communicate with the sample chamber

Methodology Applied
Scientific EffectGas expansion:

Data Source

PatentEP2225546B1Pycnometer
Publication Date: 2011.04.27 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP2225546B1 patent drawingFigure 1~2
  • EP2225546B1 patent drawingFigure 3
  • EP2225546B1 patent drawingFigure 4

AI summary

The invention relates to a device for measuring the volume of a sample, that comprises two cavities formed in a same block, pressure sensors (3, 4) mounted on the block and surrounded by a radiation shield (28) and connected to the sample chamber (1) by curved ducts. A temperature sensor (25) is also added. The apparatus can be used for measuring the volume of radioactive samples by gas expansion in an expansion chamber (2) without the radiations damaging the pressure sensors (3, 4) while allowing for the correction of temperature-rise effects.