Hydrophilic Pressure Sensor Coating to Prevent Bubble Adhesion
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Solution Overview
Problem
Existing pressure sensor units in automatic analyzers suffer from air bubble accumulation, which reduces pressure measurement accuracy due to turbulent flow and adherence of air bubbles in the connection container, despite previous techniques like swirling system water near the diaphragm not fully addressing the issue.
Innovation Solution
Forming a hydrophilic film with a contact angle of 15° or less on the inner surface of the pressure sensor unit using a silicon compound and silica or alumina particles, maintaining an arithmetic average roughness ratio of 0.8 × Ra0 ≤ Ra1, to repel air bubbles and improve flow dynamics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the diameter of the flow path expands from several millimeters to 10-15 mm in the connection container, then the pressure sensor unit can measure pressure with high sensitivity, but the flow of system water becomes turbulent and air bubbles adhere to the connection container
Solution Approach 1:
The invention changes the surface property parameter of the connection container by forming a hydrophilic film with a contact angle of 15° or less. This parameter change transforms the surface from hydrophobic to hydrophilic, preventing air bubble adhesion while maintaining the large diameter flow path necessary for sensitive pressure measurement
Solution Approach 2:
The invention uses a composite structure consisting of the connection container base material plus a hydrophilic film coating. This composite material approach combines the mechanical strength of the base material with the surface properties of the hydrophilic film, achieving both structural integrity and air bubble repellency
2Device complexity
If air bubbles adhere to the connection container and pressure sensor unit, then the pressure sensor unit structure remains simple, but pressure measurement accuracy is reduced
Solution Approach 1:
The invention applies preliminary action by forming the hydrophilic film on the connection container before air bubbles can adhere. This preventive measure ensures that when system water flows through the expanded flow path, air bubbles are repelled by the hydrophilic surface, maintaining pressure measurement accuracy without requiring complex bubble removal mechanisms
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 hydrophilic film effectively prevents air bubbles from adhering, enhancing pressure measurement accuracy and ensuring precise dispensing operations in automatic analyzers.
Implementation Method 1
forming a hydrophilic film with a contact angle of 15° or less on an inner surface of the pressure sensor unit
Data Source
Figure 1~2
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AI summary
Provided is an automatic analyzer or the like that does not leave any air bubbles inside. An automatic analyzer (1) according to the invention has a dispensing mechanism (100) including a nozzle (sample dispensing nozzle (10), reagent dispensing nozzle (11), dispensing nozzle (102), dispensing nozzle (115)) that suctions and discharges a liquid, a pressure generation unit (water supply pump (111)) that is connected to the nozzle and generates a pressure for suctioning and discharging the liquid, and a pressure sensor unit (112) that measures a pressure in a flow path (104) including the nozzle and the pressure generation unit, in which a hydrophilic film (305) containing a silicon compound and at least one of a silica particle and an alumina particle is formed on an inner surface (203a) of the pressure sensor unit (112), and a relationship between an arithmetic average roughness Ra0 of a base material (301) of the inner surface (203a) and an arithmetic average roughness Ra1 of an inner surface (203a) after the hydrophilic film (305) is formed is 0.8 × Ra0 ≤ Ra1.