Disclosure of Invention
In order to solve the technical problems, the invention aims to provide a graphene film-based liquid micro-flow metering device and a manufacturing method thereof.
The purpose of the invention is realized by the following technical scheme:
a graphene membrane based liquid micro-flow metering device comprising:
the device comprises an optical fiber sensor, a metal elastic film, a graphene film, a liquid cavity, a baffle plate, a water inlet pipeline and a timer;
the optical fiber sensor comprises an optical fiber and an optical fiber inserting core; the optical fiber is fixedly connected with one end of the optical fiber insertion core, and the grating is welded in the optical fiber;
the graphene film is fixed at one end of the optical fiber ferrule, the optical fiber is inserted through the other end of the optical fiber ferrule, and the end face of the optical fiber and the graphene film form a Fabry-Perot cavity;
one end of the liquid cavity is welded and fixed with the metal elastic film, and the other end of the liquid cavity is connected with the water inlet pipeline.
A method for manufacturing a graphene membrane-based liquid micro-flow metering device comprises the following steps:
welding the grating in the optical fiber;
the end surfaces of the optical fiber and the optical fiber ferrule are subjected to cleanliness and flatness treatment;
cutting the graphene film into a circle with a proper size, removing the PMMA coating through an acetone solution, immersing the optical fiber ferrule below the suspended graphene film, performing film fishing and wet transfer, then placing the optical fiber ferrule adsorbed with the graphene film in a drying box, heating to 40 ℃, and keeping for 1 hour, so that the dried graphene film is adsorbed on one end of the optical fiber ferrule;
after the graphene film is fixed at one end of the optical fiber ferrule, connecting and fixing the optical fiber and the other end of the optical fiber ferrule to enable the end face of the optical fiber and the graphene film to form a Fabry-Perot cavity;
welding and fixing one end of the liquid cavity and the metal elastic film together, and connecting the other end of the liquid cavity with the water inlet pipe;
one end of the optical fiber ferrule fixed with the graphene film is fixed with one end of the pipeline, the other section of the pipeline is fixed with the liquid cavity fixed with the metal elastic film, and the graphene film and the metal elastic film form an inert gas cavity.
One or more embodiments of the present invention may have the following advantages over the prior art:
the micro flow meter has the advantages of simple manufacture, small volume, high sensitivity and electromagnetic interference resistance, and can be used for measuring micro flow and calibrating the micro flow meter in the fields of biomedicine, aerospace, industrial measurement and the like.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the following embodiments and accompanying drawings.
As shown in fig. 1, the graphene film-based liquid micro-flow metering device comprises: the device comprises an optical fiber sensor, a metal elastic film 1, a graphene film 2, a liquid cavity 3, a baffle plate 4, a water inlet pipeline 5 and a timer; the optical fiber sensor comprises an optical fiber 6 and an optical fiber inserting core 7; the optical fiber is fixedly connected with one end of the optical fiber insertion core, and a grating 8 is welded in the optical fiber; the graphene film is fixed at one end of the optical fiber ferrule, the optical fiber is inserted through the other end of the optical fiber ferrule, and the end face of the optical fiber and the graphene film form a Fabry-Perot cavity 9; one end of the liquid cavity is welded and fixed with the metal elastic film, and the other end of the liquid cavity is connected with the water inlet pipeline.
A straight pipeline is arranged between the graphene film fixedly connected with the optical fiber inserting core and the metal elastic film fixed on the liquid cavity, and the graphene film and the metal elastic film form an inert gas cavity 10 through the connection of the straight pipeline. The graphene film and the optical fiber form a Fabry-Perot cavity, and the change of the length of the Fabry-Perot cavity is used for changing the reflection interference spectrum of the optical fiber. And barrier plates are arranged above and below the inside of the liquid cavity and used for reducing the impact of water flow on the graphene film. The section of the graphene film is larger than that of the optical fiber inserting core so as to fix the graphene film on the liquid cavity.
The embodiment also provides a method for manufacturing the graphene film-based liquid micro-flow metering device, which comprises the following steps:
1) the grating is soldered into the fiber by means of a fiber soldering machine.
2) The end surfaces of the optical fiber and the optical fiber ferrule are subjected to cleanliness and flatness treatment;
the method comprises the steps of cutting an optical fiber, processing the surface of a bare core, processing the surface of the end face of a ferrule, and detecting the flatness of the end face by using an end face detector; the treatment of the end face of the optical fiber ferrule is as follows: ultrasonic cleaning can be carried out, and then an optical fiber cleaning pen is selected for cleaning; for an optical fiber: and (3) cutting one end of the tail part of the optical fiber flat by using an optical fiber cutter, reserving a bare core with the length of about 1cm, enabling the end surface of the bare core to be vertical to the axial direction of the optical fiber, and then checking the flatness by using an optical fiber fusion splicer, for example, if the inclination angle between the plane and the cross section of the optical fiber is smaller than 1 degree, the optical fiber is qualified, or the optical fiber is continuously cut.
3) Cutting the graphene film into a circle with a proper size, removing the PMMA coating through an acetone solution, immersing the optical fiber ferrule below the suspended graphene film, performing film fishing and wet transfer, then placing the optical fiber ferrule adsorbed with the graphene film in a drying box, heating to 40 ℃, and keeping for 1 hour, so that the dried graphene film is adsorbed on one end of the optical fiber ferrule;
4) after the graphene film is fixed at one end of the optical fiber ferrule, connecting and fixing the optical fiber and the other end of the optical fiber ferrule to enable the end face of the optical fiber and the graphene film to form a Fabry-Perot cavity;
and (3) performing welding treatment on the joint of the end face of the optical fiber and the end face of the optical fiber ferrule, wherein low-temperature welding or laser welding can be selected.
5) Welding and fixing one end of the liquid cavity and the metal elastic film together, and connecting the other end of the liquid cavity with the water inlet pipe;
6) one end of the optical fiber ferrule fixed with the graphene film is fixed with one end of the pipeline, the other section of the pipeline is fixed with the liquid cavity fixed with the metal elastic film, and the graphene film and the metal elastic film form an inert gas cavity.
The joint of one end of the optical fiber ferrule fixed with the graphene film and one end of the pipeline is connected by adopting a welding flux, laser or consolidation mode, and the like, and the elastic metal diaphragm is connected with the liquid cavity by adopting a welding flux or laser welding.
The Fabry-Perot cavity formed by the graphene film optical fiber changes the relation of reflection interference spectrum of the optical fiber, such as light intensity and frequency of the spectrum, through the change of the length of the Fabry-Perot cavity.
The volume of water can be obtained by calculating the flow and the time, the change of the optical fiber reflection interference spectrum caused by the increase of the volume of water can be changed into the change of the optical fiber reflection interference spectrum caused by the size of the flow, the timing is started when the water is input again, meanwhile, the optical fiber measuring point is aligned to the circle center of the graphene film, the reflected light spectrum and the time data are recorded, the experiment is carried out for many times, other variables are unchanged, only the flow is changed, and the relation between the flow and the reflection interference spectrum measured by the optical fiber is found out; the water flow flows into the liquid cavity from the water inlet pipe, the barrier plate is arranged in the liquid cavity to reduce the impact of the water flow on the graphene film, and the other end of the liquid cavity is provided with the metal elastic film; before the test starts, a water flow is added to make the metal elastic film in a strain-free state.
As shown in fig. 2, after the part of water flowing into the liquid chamber makes the metal elastic membrane in a non-strain state (neither concave nor convex); after the measurement is started, water continuously flows into the liquid cavity through the water inlet pipe (the timer starts to time and is recorded as t)0) The metal elastic film is deformed (protruded outwards) due to the increase of the volume of water in the liquid cavity, so that the air pressure in the inert gas cavity is increased, and the graphene film is strained due to the increase of the air pressure, namely the graphene film and the inert gasThe length of the Fabry-Perot cavity formed by the optical fiber changes, which causes the reflection interference spectrum of the optical fiber to change (such as the frequency and the light intensity to change), when the volume of water in the liquid cavity is filled quickly, the measurement such as the input of water is stopped (the timer stops counting and is recorded as t)1). It can be concluded that the increase of the volume of water in the liquid chamber is the main cause of the change of the reflection interference spectrum (such as the change of frequency and light intensity) measured by the optical fiber, and enters the optical fiber regulator 12 through the jumper 11 to obtain the relationship between the chamber length and the interference spectrum, and then the volume of the water flowing in after the timing is started can be obtained by calculating the flow and the time by knowing the time and the flow of the water. Therefore, the relationship between the flow rate of water and the change of the reflection interference spectrum of the optical fiber can be known. The flow of water is changed, and the relation between the reflection interference spectrum (such as light intensity and frequency) of the optical fiber measured by the optical fiber and the flow of the added water is found out through a plurality of experiments, so that the micro flow is measured.
Although the embodiments of the present invention have been described above, the above descriptions are only for the convenience of understanding the present invention, and are not intended to limit the present invention. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.