CN212008398U - Contactless capacitance detection device for oil pollutants - Google Patents
Contactless capacitance detection device for oil pollutants Download PDFInfo
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- CN212008398U CN212008398U CN202020418008.0U CN202020418008U CN212008398U CN 212008398 U CN212008398 U CN 212008398U CN 202020418008 U CN202020418008 U CN 202020418008U CN 212008398 U CN212008398 U CN 212008398U
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Abstract
The utility model provides a non-contact capacitance detection device for oil pollutants, which comprises a power unit, a non-contact capacitance detection chip, an analysis unit and a display unit; the power unit drives the oil to be detected to flow through a detection channel of the non-contact capacitance detection chip; the non-contact capacitance detection chip is used for carrying out capacitance detection on the oil pollutants and generating capacitance output signals representing the oil pollutants; the analysis unit provides a high-frequency sine wave excitation signal, collects and analyzes the capacitance output signal and generates a capacitance output curve representing oil pollutants; and the display unit is used for displaying a capacitance output curve representing oil pollutants in real time. The invention is based on the contactless capacitance detection chip to carry out capacitance detection on oil pollutants, and has the advantages of low processing cost, good repeatability and difficult pollution.
Description
Technical Field
The invention relates to the field of oil pollutant detection, in particular to a non-contact capacitance detection device for oil pollutants.
Background
The quality of the oil is directly related to the working state of mechanical equipment. The on-line detection of main pollutants in oil of mechanical equipment can realize early fault prevention and diagnosis of the mechanical equipment, so that the service life of the mechanical equipment is prolonged, and the economic cost is saved. The capacitance detection is carried out by utilizing the difference between the dielectric constants of the oil liquid pollutants and the dielectric constants of the oil liquid, and the capacitance detection precision is high for the moisture pollutants and the air pollutants in the oil liquid, so that the micro-fluidic capacitance detection chip is commonly used for detecting the moisture pollutants and the air pollutants in the oil liquid pollutant detection. At present, electrodes required by the microfluidic capacitance detection chip are mainly manufactured by the following two methods. Firstly, a pair of parallel metal electrodes is manufactured below a micro-channel of a micro-fluidic chip by a sputtering method to form a plane capacitor for detection. The method has high cost, and the capacitor electrode is easy to be polluted because of direct contact with the oil. The other method is to place copper wires at the centers of two sides of the oil channel to realize the preparation of the capacitive sensor of the microfluidic chip. The method has the advantages of low processing precision and poor repeatability, and the capacitor electrode is easily polluted. Therefore, the capacitance detection device and method which are low in processing cost of the capacitance electrode, good in repeatability and not easy to be polluted have important significance.
Disclosure of Invention
According to the technical problems of high processing cost, poor repeatability and easy pollution of the capacitor electrode in the capacitance detection, the non-contact capacitance detection device for the oil pollutants is provided. The utility model discloses detect based on contactless electric capacity detects the chip, low, the good reproducibility of processing cost, be difficult to contaminated.
The utility model discloses a technical means as follows:
a non-contact capacitance detection device for oil pollutants comprises a power unit, a non-contact capacitance detection chip, an analysis unit and a display unit; the power unit drives the oil to be detected to flow through a detection channel of the non-contact capacitance detection chip; the non-contact capacitance detection chip is used for carrying out capacitance detection on the oil pollutants and generating capacitance output signals representing the oil pollutants; the analysis unit provides a high-frequency sine wave excitation signal, collects and analyzes the capacitance output signal and generates a capacitance output curve representing oil pollutants; the display unit is used for displaying a capacitance output curve.
Compared with the prior art, the invention has the following advantages:
1. the utility model provides a contactless electric capacity detects chip, when carrying out fluid and examine time measuring, contactless electric capacity electrode can avoid with the fluid direct contact that awaits measuring.
2. The utility model provides a contactless electric capacity electrode is formed by the preparation of soft lithography, can accurately produce corresponding chip passageway through drawing software AutoCAD behind the design access structure to the silica-based mould that makes can recycle, and this makes contactless electric capacity electrode have higher machining precision and good repeatability.
3. The utility model provides a conducting liquid optional scope is wide, the conducting liquid of optional low price to fall the cost of manufacture who detects chip capacitor electrode.
4. The utility model discloses corresponding detection device and method are designed out based on contactless electric capacity detects chip. The detection device has a simple structure and reliable detection results, and meets the requirements of practical detection and application.
To sum up, the utility model provides an among the prior art capacitance detection capacitance electrode processing cost higher, the relatively poor, the easy contaminated problem of repeatability.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
Fig. 1 is a structural diagram of the non-contact capacitance detection device for detecting oil contaminants.
Fig. 2 is a structural diagram of the contactless capacitance detecting chip of the present invention.
Fig. 3 is a top view of the contactless capacitance detection chip of the present invention.
In the figure: A. a power unit; B. a contactless capacitance detection chip; C. an analysis unit; D. a display unit; E. a contactless capacitive sensor; F. a contactless capacitive electrode; 1. a glass substrate; 2. A PDMS matrix; 3. an oil passage; 4. an oil inlet; 5. an oil outlet; 6. an electrode lead interface; 7. a conductive liquid inlet; 8. a conductive liquid outlet; 9. an electrode main channel; 10. the electrodes detect the channels.
Detailed Description
It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The utility model provides a non-contact capacitance detection device for oil pollutants, which comprises a power unit, a non-contact capacitance detection chip, an analysis unit and a display unit; the power unit drives the oil to be detected to flow through a detection channel of the non-contact capacitance detection chip; the non-contact capacitance detection chip is used for carrying out capacitance detection on the oil pollutants and generating capacitance output signals representing the oil pollutants; the analysis unit provides a high-frequency sine wave excitation signal, collects and analyzes the capacitance output signal and generates a capacitance output curve representing oil pollutants; the display unit is used for displaying a capacitance output curve.
Further, the non-contact capacitance detection chip comprises a glass substrate and a PDMS matrix; an oil channel for oil to flow is arranged on the PDMS substrate, an oil inlet and an oil outlet are respectively arranged at two ends of the oil channel, and oil flows in the direction from the oil inlet to the oil outlet under the driving of the power unit; the oil passage is provided with a non-contact capacitance sensor which comprises non-contact capacitance electrodes which are oppositely arranged at corresponding positions on two sides of the oil passage and have the same structure.
Furthermore, the non-contact capacitance electrode comprises an electrode lead interface, conductive liquid, a conductive liquid inlet, a conductive liquid outlet, an electrode main channel and an electrode detection channel; the electrode detection channel is a U-shaped channel which is close to and back to the oil channel, the electrode main channel is connected to the tail end of the electrode detection channel in a right-angle turning mode, the width of the electrode detection channel is half of that of the electrode main channel, and the tail end of the electrode main channel is provided with a conductive liquid inlet and a conductive liquid outlet; the electrode lead interface is a copper wire with a certain length, the conductive liquid inlet and the conductive liquid outlet are connected in a bridging mode through the electrode lead interface, and the electrode lead interface extends into the conductive liquid inlet and the conductive liquid outlet to a depth which ensures that the tail end of the electrode lead interface is below the liquid level of the conductive liquid.
Example 1
As shown in fig. 1, the invention provides a non-contact capacitance detection device for oil contaminants, which comprises a power unit a, a non-contact capacitance detection chip B, an analysis unit C and a display unit D, wherein:
the power unit A selects a micro-injection pump (model: HARVARD 70-2212) to drive the oil liquid pollutant to be detected containing the water pollutant and the air pollutant to pass through the non-contact capacitance detection chip B.
As shown in fig. 2 and 3, the contactless capacitance detection chip B includes a glass substrate 1, a PDMS matrix 2; the PDMS matrix 2 comprises an oil inlet 4, an oil channel 3 and an oil outlet 5 which are communicated, and the oil channel 3 is provided with a non-contact capacitive sensor E; the non-contact capacitive sensor E can perform capacitive detection on the oil pollutants and output capacitive output signals representing the oil pollutants; the non-contact capacitive sensor E consists of two non-contact capacitive electrodes F which have the same structure and are arranged on two sides of the oil channel 3 in an opposite mode; the non-contact capacitance electrode F consists of an electrode lead interface 6, a conductive liquid inlet 7, a conductive liquid outlet 8, an electrode main channel 9, an electrode detection channel 10 and conductive liquid; the conductive liquid is NaCl solution with the mass fraction of 25%; the electrode detection channel 10 is a U-shaped channel which is close to and back to the oil channel 3, the electrode main channel 9 is connected to the tail end of the electrode detection channel 10 in a right-angle turning mode, the width of the electrode detection channel 10 is half of that of the electrode main channel 9, and the tail end of the electrode main channel 9 is provided with a conductive liquid inlet 7 and a conductive liquid outlet 8; the electrode lead interface 6 is a copper wire with a certain length, the conductive liquid inlet 7 and the conductive liquid outlet 8 are connected in a bridging mode through the electrode lead interface 6, and the electrode lead interface 6 extends into the conductive liquid inlet 7 and the conductive liquid outlet 8 to a depth which ensures that the tail end of the electrode lead interface is below the liquid level of the conductive liquid.
And the analysis unit C selects an impedance analyzer to provide a high-frequency sine wave excitation signal, collects and analyzes the capacitance output signal and generates a capacitance output curve representing oil pollutants.
The display unit D is LabView software on a computer, receives the capacitance output curve from the analysis unit C, and displays the capacitance output curve on the computer in a real-time curve mode.
The method for detecting the oil pollutants by using the non-contact capacitance detection device comprises the following specific steps:
(1) filling oil to be detected containing water pollutants and air pollutants into a power unit A, and connecting the power unit A with a non-contact capacitance detection chip B; connecting two electrode lead interfaces 6 on the chip with an analysis unit C by using insulated leads; connecting the analysis unit C with the display unit D; completing the construction of the oil pollutant non-contact capacitance detection device and starting a power supply;
(2) starting the power unit A, and driving the oil to be detected to pass through the non-contact capacitor detection chip B;
(3) starting an analysis unit C, wherein the analysis unit C generates a high-frequency sine wave excitation signal to a non-contact type capacitance detection chip B;
(4) a non-contact capacitance sensor E in the non-contact capacitance detection chip B receives the excitation signal and performs capacitance detection to generate a capacitance output signal representing the oil pollutants to an impedance analyzer C;
(5) the analysis unit C receives the capacitance output signal and performs acquisition and analysis processing on the capacitance output signal to generate a capacitance output curve representing oil pollutants and sends the capacitance output curve to the display unit D;
(6) starting a display unit D, and displaying a capacitance output curve on a computer in real time;
(7) analyzing pulses on the capacitance output curve, wherein when the moisture pollutants pass through the detection chip, positive pulses appear on the capacitance output curve, and when the air pollutants pass through the detection chip, negative pulses appear on the capacitance output curve; analyzing and calculating the pulse number and the pulse amplitude on the capacitance output curve to obtain the concentration and the size of the moisture pollutants or the air pollutants;
the utility model also provides a manufacturing method of contactless electric capacity detects chip B, including following step:
step 1: and (6) drawing software. Designing a mask channel structure through drawing software AutoCAD;
step 2: and manufacturing a mask. After the structural design of the mask channel is finished, a mask is printed by using a professional mask printer; the mask is used for forming chip channels on the silicon-based mold after ultraviolet exposure.
And step 3: and (5) manufacturing a silicon-based mold. Uniformly spin-coating the negative photoresist (SU-82015) on a silicon wafer by using a spin coater at a rotating speed of 1500 r/min; putting the silicon wafer coated with the negative photoresist with a certain thickness into a heater for pre-baking treatment, firstly heating at 65 ℃ for 2min, and then heating at 95 ℃ for 4 min; covering the printed mask film right above the pre-baked silicon wafer, and performing ultraviolet exposure treatment by using an ultraviolet exposure instrument at a dose of 150mJ/cm 2; placing the silicon wafer subjected to ultraviolet exposure into a heater for post-baking treatment, and heating at 95 ℃ for 5 min; soaking the post-baked silicon wafer in a developer, and carrying out development treatment for 5min, wherein the negative photoresist on the silicon wafer which is not irradiated by light rays is dissolved, and the channel part irradiated by the light rays is not dissolved; the developed silicon wafer gradually shows a chip channel structure which is the same as the mask design; taking out the silicon wafer, cleaning the silicon wafer with acetone, cleaning the silicon wafer with plasma water, and finally drying the silicon wafer with nitrogen, so that the silicon-based mold is manufactured and can be recycled;
and 4, step 4: a PDMS slab was fabricated. Uniformly mixing PDMS (polydimethylsiloxane) and a curing agent according to a ratio of 10:1, putting the mixture into a vacuum box, and performing air extraction treatment for 40 min; pouring the PDMS glue after air exhaust into a silicon-based mold; placing the silicon-based mold into an oven, and baking for 30min to change the PDMS from liquid PDMS glue into a solid PDMS sheet, wherein the thickness of the PDMS sheet is about 2-3 mm; after baking is finished, separating the PDMS sheet from the silicon-based mold, and forming a channel sunken in the PDMS material on one side of the PDMS sheet close to the silicon-based mold; coating the PDMS sheet with a clean preservative film to prevent pollution;
and 5: and (6) punching a liquid injection hole. The liquid injection hole in the chip comprises an oil liquid inlet 4, an oil liquid outlet 5, a conductive liquid inlet 7 and a conductive liquid outlet 8; punching the liquid injection holes by a puncher respectively;
step 6: and (4) plasma bonding. Putting the glass sheet into a glass bottle filled with an acetone solution, and soaking for 5 min; putting the glass bottle filled with the glass sheets into an ultrasonic cleaning machine, and ultrasonically cleaning for 5 min; after ultrasonic cleaning, taking out the glass sheet, cleaning the glass sheet with plasma water, and blowing the glass sheet clean with nitrogen; taking out the PDMS sheet and blowing the PDMS sheet clean by nitrogen; putting the glass sheet and the PDMS sheet which are fully washed by the nitrogen into a plasma cleaning machine for cleaning for 2 min; taking out the glass sheet and the PDMS sheet, and bonding one side of the PDMS sheet with the channel with the glass sheet;
and 7: and injecting a conductive liquid. Preparing a NaCl solution with the mass fraction of 25% as a conductive liquid; injecting a NaCl solution into the non-contact capacitance electrode F from the conductive liquid inlet 7 by using an injector; when the air in the non-contact capacitor electrode F is exhausted, NaCl solution is filled in the non-contact capacitor electrode F;
and 8: and manufacturing an electrode lead interface 6. Inserting two ends of a copper wire with proper length into the conductive liquid inlet 7 and the conductive liquid outlet 8 respectively, and contacting with a NaCl solution serving as conductive liquid so as to connect the conductive liquid inlet with the conductive liquid outlet; the conductive liquid inlet 7 and the conductive liquid outlet 8 are sealed and blocked by an adhesive (705rtv transparent silicon rubber); the copper wire is the electrode lead interface 6.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.
Claims (2)
1. The utility model provides an oil pollutant contactless electric capacity detection device which characterized in that, includes power pack, contactless electric capacity detection chip, analysis unit and display element, wherein:
the power unit drives the oil to be detected to flow through a detection channel of the non-contact capacitance detection chip;
the non-contact capacitance detection chip is used for carrying out capacitance detection on the oil pollutants and generating capacitance output signals representing the oil pollutants;
the analysis unit provides a high-frequency sine wave excitation signal, collects and analyzes the capacitance output signal and generates a capacitance output curve representing oil pollutants;
the display unit is used for displaying the capacitance output curve;
the non-contact capacitance detection chip comprises a glass substrate and a PDMS matrix; an oil channel for oil to flow is arranged on the PDMS substrate, an oil inlet and an oil outlet are respectively arranged at two ends of the oil channel, and oil flows in the direction from the oil inlet to the oil outlet under the driving of the power unit;
the oil passage is provided with a non-contact capacitance sensor which comprises non-contact capacitance electrodes which are oppositely arranged at corresponding positions on two sides of the oil passage and have the same structure;
the non-contact capacitance electrode comprises an electrode lead interface, conductive liquid, a conductive liquid inlet, a conductive liquid outlet, an electrode main channel and an electrode detection channel;
the electrode detection channel is close to and faces away from the U-shaped channel arranged in the oil liquid channel, the electrode main channel is connected to the tail end of the electrode detection channel in a right-angle turning mode, the width of the electrode detection channel is half of that of the electrode main channel, and the tail end of the electrode main channel is provided with a conductive liquid inlet and a conductive liquid outlet.
2. The apparatus according to claim 1, wherein the electrode lead interface is a copper wire having a length, the conductive liquid inlet and the conductive liquid outlet are connected by bridging the electrode lead interface, and the electrode lead interface extends into the conductive liquid inlet and the conductive liquid outlet to a depth that ensures that the end of the electrode lead interface is below the level of the conductive liquid.
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| CN202020418008.0U CN212008398U (en) | 2020-03-27 | 2020-03-27 | Contactless capacitance detection device for oil pollutants |
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| CN202020418008.0U CN212008398U (en) | 2020-03-27 | 2020-03-27 | Contactless capacitance detection device for oil pollutants |
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