Pressure Detection Device with Inverted Transmission for Negative Pressure
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Solution Overview
Problem
Conventional pressure sensors cannot accurately detect negative pressures in fluids due to their design, which relies on force detection at the lower surface, leading to inaccuracies when the fluid pressure is temporarily reduced, and issues like air bubbles or film wrinkles in adhesives further complicate measurements.
Innovation Solution
A pressure detection device with a pressure transmission portion that receives an urging force from a pressure receiving portion, allowing it to accurately detect fluid pressure even when it becomes negative by subtracting the corresponding pressure value from the urging force, and featuring a structure that minimizes volume fluctuations and peeling at joint portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional pressure sensor with a protective sheet is used to detect fluid pressure, then positive pressure detection is accurate, but negative pressure detection becomes inaccurate when the protective sheet separates from the sensor body
Solution Approach 1:
Instead of having the protective sheet press against the lower surface of the sensor body to detect pressure, the invention inverts the structure so that the pressure receiving portion is pressed against the upper surface of the pressure transmission portion. This allows the sensor to detect pressure changes from the opposite direction, enabling accurate negative pressure detection while maintaining positive pressure detection accuracy.
Solution Approach 2:
The pressure transmission portion acts as an intermediary element between the fluid and the sensor body. It transmits pressure forces from the pressure receiving portion to the sensor body, allowing accurate pressure detection while preventing direct contact issues between the protective sheet and sensor body that cause separation under negative pressure.
2Strength
If adhesive is used to mount the sensor, then the sensor is securely fixed, but air bubbles form in the adhesive or films develop wrinkles, compromising measurement accuracy
Solution Approach 1:
The invention extracts and eliminates the adhesive layer from the mounting structure. By using a mechanical pressing structure where the pressure receiving portion is directly pressed against the pressure transmission portion, it removes the source of air bubbles and wrinkles that compromise measurement accuracy, while still achieving secure fixation through mechanical means.
3Measurement precision
If the pressure receiving portion is displaced by fluid pressure, then pressure detection is enabled, but volume fluctuations occur in the internal space, affecting measurement stability
Solution Approach 1:
The pressure receiving portion is designed as a flexible thin film that can deform under pressure while maintaining a sealed structure. This flexibility allows it to transmit pressure forces accurately to the pressure transmission portion while preventing volume fluctuations in the internal space, ensuring measurement stability.
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
Enables accurate detection of fluid pressure, including negative pressures, by locally concentrating pressure on the detection portion, reducing errors and maintaining consistent contact areas, thus enhancing measurement accuracy.
Implementation Method 1
a pressure receiving portion configured to be displaced by receiving a pressure of the fluid circulated through the flow channel
Implementation Method 2
the pressure transmission portion being configured to transmit, to the pressure detection portion, the pressure of the fluid received by the pressure receiving portion
Implementation Method 3
The pressure sensor disclosed in PTL 1 is a capacitance type or piezoelectric type pressure sensor which obtains, as a detected value, a force generated when the lower surface of the sensor body is pressed
Implementation Method 4
The pressure sensor disclosed in PTL 1 is a capacitance type or piezoelectric type pressure sensor which obtains, as a detected value, a force generated when the lower surface of the sensor body is pressed
Data Source
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AI summary
Provided is a pressure detection device including: a pressure detection unit; and a flow channel unit provided with a flow channel and a pressure receiving portion. The pressure detection unit includes a pressure sensor including a diaphragm, and a pressure transmission portion which is disposed in a state where one end of the pressure transmission portion is in contact with the diaphragm and the other end thereof is in contact with the diaphragm, and transmits a pressure of a fluid received by the diaphragm to the diaphragm. The pressure transmission portion is disposed in a state where the diaphragm is displaced toward the flow channel and an urging force directed from the diaphragm to the diaphragm is received.