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A nanoliter capacitive liquid level sensor and its preparation method

A liquid level sensor, capacitive technology, applied in the field of liquid level sensor

Active Publication Date: 2019-12-24
XI AN JIAOTONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to design a nano-liter capacitive liquid level sensor and its preparation method to solve the detection problem of weak liquid level and volume change in the field of microfluidics

Method used

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  • A nanoliter capacitive liquid level sensor and its preparation method
  • A nanoliter capacitive liquid level sensor and its preparation method
  • A nanoliter capacitive liquid level sensor and its preparation method

Examples

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Embodiment 1

[0034] like figure 1 Shown: a continuous nanoliter capacitive liquid level sensor based on MEMS technology, suitable for the bioreactor structure in the field of microfluidics, the liquid level sensor is installed on the outer surface of the bioreactor 1, and the bioreactor 1 is opened There are a container outlet 12 and a container inlet 9, the liquid in the bioreactor 1 enters the liquid level sensor through the container outlet 12, and then returns to the bioreactor 1 from the container inlet 9.

[0035] like figure 2 As shown, the capacitive liquid level sensor includes: PDMS layer 2 , Si structure layer 3 and glass layer 4 . Among them, the function of PDMS layer 2 is to encapsulate the sensor on the outer surface of the bioreactor. Of course, other materials can be used in addition to PDMS, as long as the sensor can be encapsulated on the outer surface of the bioreactor. In order to communicate with the interior of the bioreactor, the PDMS layer is provided with a liq...

Embodiment 2

[0043] Such as Figure 8 As shown, the difference between this embodiment and one of the specific embodiments is that: the horizontal gaps 19 are equidistantly arranged between the serpentine inner surface gaps, and the oxidation insulation treatment is done; the other is the same as the one of the specific embodiments. This embodiment can accurately monitor individual sensitive liquid level points on the basis of continuous liquid level measurement. When the liquid level reaches the transverse gap, the capacitance change of the system is obviously higher than usual, which is very beneficial for occasions that are sensitive to liquid level and volume transmission.

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Abstract

The invention discloses a capacitive liquid level sensor and a manufacturing method thereof. The liquid level sensor comprises a surface PDMS layer, a Si structure layer and a bottom glass layer, wherein the Si structure layer and electrodes are obtained through a process combining DRIE dry etching and wet etching; a closed liquid cavity is formed through ion bonding and the PDMS layer, and the change of electrolyte between capacitance polar plates is caused by the change of the liquid level, so that the electric charge between the capacitance polar plates is changed; the change of the liquid level between the polar plates can be detected through a peripheral circuit. Due to the fact that the distances are equal everywhere, the volume of the liquid between the polar plates can be calculated accurately and directly; the second embodiment of invention can achieve accurate monitoring of the characteristic liquid level, and overall continuous observation can be achieved. The liquid sensor has the advantages of being sensitive in reaction, low in manufacturing cost, high in precision and the like.

Description

【Technical field】 [0001] The invention relates to the technical field of liquid level sensors, in particular to a high-precision continuous capacitive liquid level sensor based on MEMS technology. 【Background technique】 [0002] In the industrial field, in order to realize automatic production and measurement, precise measurement of liquid level is required. [0003] Liquid level measurement includes liquid level annunciator and continuous liquid level measurement. The former mainly monitors and warns several fixed liquid level positions, while the latter requires continuous liquid level measurement in the full range, and is widely used in petrochemical, biopharmaceutical micro-flow control and other fields. [0004] At present, there are more than 20 methods used in continuous liquid level measurement, such as float method, laser interferometry, magnetostrictive method, etc. In practical applications, it is necessary to select a suitable measurement method according to cer...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01F23/26
CPCG01F23/263
Inventor 韦学勇张宏才王威威蒋庄德
Owner XI AN JIAOTONG UNIV
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