Light-Shielding Structure for Sample Measuring Device Shaft
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Solution Overview
Problem
In sample measurement devices, particularly liquid scintillation counters, ensuring reliable light shielding at the lower part of the measurement chamber is challenging due to the presence of a shaft that penetrates through, making it difficult to prevent extrinsic light intrusion, especially during vibrations or machining errors.
Innovation Solution
The implementation of a light-shielding structure over the upper and lower surfaces of the base frame and head, combined with an elastic member and a shutter mechanism, effectively blocks extrinsic light and radiation by using a protrusion-recess engagement and a layered structure with a light-shielding sheet and reflective layer, ensuring precise positioning and efficient light focusing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a shaft is used to lift and lower the sample container through the measurement chamber, then the sample container can be transported between the rack and measurement chamber, but extrinsic light can intrude into the measurement chamber through gaps around the shaft
Solution Approach 1:
A light-shielding structure is introduced as an intermediary element between the shaft and the measurement chamber environment. This structure includes a light-shielding sheet and reflective layer that act as mediators to block extrinsic light from reaching the measurement chamber through gaps around the shaft, while allowing the shaft to maintain its lifting and lowering function.
Solution Approach 2:
The solution addresses the light intrusion problem by adding a dimensional layer - a light-shielding structure with multiple layers (light-shielding sheet and reflective layer) wrapped around the shaft. This multi-layer dimensional approach creates effective light blocking without interfering with the shaft's vertical movement function.
2Object-affected harmful factors
If the measurement chamber is provided below the rack placement surface to avoid light shielding issues, then light shielding is improved, but the shaft still penetrates through creating potential gaps
Solution Approach 1:
The light-shielding structure is designed with beforehand cushioning considerations. The multiple layers (light-shielding sheet and reflective layer) are arranged to accommodate potential vibrations and machining errors, creating a redundant barrier system that maintains light blocking effectiveness even when gaps may form due to vibration or assembly variations.
Solution Approach 2:
The light-shielding structure employs composite materials approach by combining different types of light-blocking layers. The light-shielding sheet and reflective layer work together as a composite structure, where each layer provides different light blocking mechanisms, creating a more reliable shield against extrinsic light under various operating conditions including vibration.
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 configuration provides robust light shielding, preventing unintentional gaps and extrinsic light intrusion, even with slight assembly errors, and allows for precise positioning of the sample container, enhancing measurement accuracy and reliability.
Implementation Method 1
an elastic member provided between the upper end and the head body, and the elastic member realizes an elastic function in the base state
Implementation Method 2
a light-shielding structure is formed over these surfaces, intrusion of extrinsic light into the sample measurement chamber (in particular, intrusion of the extrinsic light along the shaft surface) is prevented by the light-shielding structure
Implementation Method 3
a layered structure with a light-shielding sheet and reflective layer, ensuring precise positioning and efficient light focusing
Data Source
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AI summary
In this sample measuring device a lifting mechanism conveys a sample container from a rack to a sample measuring chamber. An inside light-shielding structure is extended over the upper surface of a base frame and the lower surface of a head, and surrounds a shaft. The inside light-shielding structure is configured from a first ring groove and a first ring protrusion. When the head is in a ground state, the upper surface of the base frame and the lower surface of the head are contacted by the action of a spring. At this time, the first ring groove and the first ring protrusion are integrated. An outside light-shielding structure is provided to the periphery of the inside light-shielding structure. A top plate contains a laminate structure which includes a lightshielding sheet and a lightreflecting plate.