1. A QCM-based fluid viscosity monitor, comprising:

the QCM sensor comprises a piezoelectric quartz wafer, an upper electrode (detection electrode) and a lower electrode, wherein the piezoelectric quartz wafer is circular, the upper electrode is circular sheet-shaped and covers the upper part of the piezoelectric quartz wafer as the detection electrode, and the lower electrode is circular sheet-shaped and covers the lower part of the piezoelectric quartz wafer as the grounding electrode;

the columnar ring is used for annularly packaging the upper surface of the QCM sensor, an upper electrode is placed in the columnar ring, and the columnar ring and the upper surface of the piezoelectric quartz wafer form a liquid detection pool for containing various liquids to be detected;

the wafer integral support comprises two support rods with the length of L, the two support rods are aligned in parallel, and the front ends of the two support rods are fixedly connected with the left outer edge and the right outer edge of the QCM sensor respectively to provide physical support for the QCM sensor;

electrode leads of the upper electrode and the lower electrode are respectively connected with the upper electrode and the lower electrode and then respectively connected to the supporting rods at the left outer edge and the right outer edge of the QCM sensor, and the wafer integral support is a conductor and provides conductivity for the QCM sensor;

the supporting rod is vertical to the wafer integral support, the wafer integral support is placed on the supporting rod, the supporting rod provides support for the wafer integral support and forms a lever, and the supporting rod is a fulcrum of the lever;

the lower surfaces of the two detection rods are covered with pressure detection sensors, and the rear ends of the two support rods of the wafer integral support are respectively arranged below the detection rods and are in contact with the pressure detection sensors;

for the wafer integral support, the distance between the supporting rod and the detection rod is L2 which is less than or equal to half of the length L of the wafer support, so that the wafer integral support, the supporting rod and the detection rod form a lever system;

the detection circuit is connected with the rear ends of the two support rods of the wafer integral support, the detection circuit drives the QCM sensor and obtains the resonant frequency of the QCM sensor, meanwhile, the detection circuit is connected with the pressure detection sensors covered on the lower surfaces of the two detection rods, the detection circuit drives the pressure sensors and obtains the induced pressure of the pressure sensors, a central processing unit in the detection circuit firstly calculates the mass of the liquid to be detected according to the obtained induced pressure and the lever force arm proportion, then calculates the density of the liquid to be detected according to the volume of the added liquid to be detected, and finally calculates the viscosity of the detected liquid through a Kanazawa equation in combination with the change of the resonant frequency.

2. A QCM-based fluid viscosity monitor according to claim 1, wherein the QCM sensor is ring-packaged and then fixedly attached at its left and right outer edges to the wafer monolith support, which is connected to the upper and lower electrodes of the QCM sensor by the electrode leads of the upper and lower electrodes, respectively, thus forming a QCM sensor package assembly;

clamping a wafer integral support by using tweezers to insert the QCM sensor packaging assembly into the instrument, wherein the wafer integral support is carried on the supporting rods, and the rear ends of two supporting rods of the wafer integral support are respectively arranged below the detection rods and are contacted with the pressure detection sensor to form a lever state;

measurement is accomplished, extracts QCM sensor encapsulation subassembly and throws into corresponding garbage bin.

Background

Viscosity is a physicochemical property of a substance. For some applications, the specific value of the liquid and the accuracy of the detection are particularly important. At present, the commonly used liquid viscosity detection methods mainly comprise a capillary type, a vibration type, a rotary type and the like, the commercial liquid viscometer mainly adopts the rotary type, and the capillary type and the vibration type can only be applied to laboratories due to the complex operation and the troublesome maintenance.

For a common liquid viscosity detection method, whether used in a laboratory or in a commercial manner, the operation and maintenance are complicated, and the requirement for the amount of liquid is also large, for example, a commercial rotary liquid viscometer needs to place hundreds of milliliters of liquid in a barrel and then place a rotary rod in the barrel to rotate for a certain time. The detection process is tedious and time-consuming, the cleaning and maintenance of the equipment are troublesome, and especially when toxic and harmful liquid is detected, the cleaning and maintenance are improper and even harm can be caused to human bodies.

Quartz Crystal Microbalance (QCM) is a mass-type sensor with nanogram magnitude that emerged in the sixties of the last century (G. Sauerbry. use of Quartz vibration for weighing thin film on a Microbalance [ J ]. Physik, 1968,155: 206-212). Until 1985, Kanazawa et al (K.Keiji Kanazawa, Joseph G.Gordon. frequency of aqua microbalance in contact with liquid [ J ]. Analytical Chemistry, 1985, 57: 1770-1771) discovered a change in the resonance frequency of QCM as a function of the density and viscosity of the liquid in contact, as shown below.

Eta and rho are liquid viscosity and density, mu_qAnd ρ_qIs the shear modulus and density of the quartz crystal, and deltaf is the corresponding change in resonant frequency.

By the relationship between the density and viscosity of the liquid and the change of the resonant frequency, we can find that the density and viscosity of the liquid are coupled together. Therefore, before a mathematical decoupling method is not available, the density of the liquid can only be measured by other methods before a specific viscosity value is obtained, but this results in a tedious and time-consuming whole viscosity detection process.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide the liquid viscosity detector based on the QCM, which has the advantages of convenience in detection, simplicity in operation, simplicity in maintenance and small required liquid amount.

In order to achieve the above object, the present invention provides a QCM-based liquid viscosity measuring instrument, comprising:

the QCM sensor comprises a piezoelectric quartz wafer, an upper electrode (detection electrode) and a lower electrode, wherein the piezoelectric quartz wafer is circular, the upper electrode is circular sheet-shaped and covers the upper part of the piezoelectric quartz wafer as the detection electrode, and the lower electrode is circular sheet-shaped and covers the lower part of the piezoelectric quartz wafer as the grounding electrode;

the columnar ring is used for annularly packaging the upper surface of the QCM sensor, an upper electrode is placed in the columnar ring, and the columnar ring and the upper surface of the piezoelectric quartz wafer form a liquid detection pool for containing various liquids to be detected;

the wafer integral support comprises two support rods with the length of L, the two support rods are aligned in parallel, and the front ends of the two support rods are fixedly connected with the left outer edge and the right outer edge of the QCM sensor respectively to provide physical support for the QCM sensor;

electrode leads of the upper electrode and the lower electrode are respectively connected with the upper electrode and the lower electrode and then respectively connected to the supporting rods at the left outer edge and the right outer edge of the QCM sensor, and the wafer integral support is a conductor and provides conductivity for the QCM sensor;

the supporting rod is vertical to the wafer integral support, the wafer integral support is placed on the supporting rod, the supporting rod provides support for the wafer integral support and forms a lever, and the supporting rod is a fulcrum of the lever;

the lower surfaces of the two detection rods are covered with pressure detection sensors, and the rear ends of the two support rods of the wafer integral support are respectively arranged below the detection rods and are in contact with the pressure detection sensors;

for the wafer integral support, the distance between the supporting rod and the detection rod is L2 which is less than or equal to half of the length L of the wafer support, so that the wafer integral support, the supporting rod and the detection rod form a lever system;

the detection circuit is connected with the rear ends of the two support rods of the wafer integral support, the detection circuit drives the QCM sensor and obtains the resonant frequency of the QCM sensor, meanwhile, the detection circuit is connected with the pressure detection sensors covered on the lower surfaces of the two detection rods, the detection circuit drives the pressure sensors and obtains the induced pressure of the pressure sensors, a central processing unit in the detection circuit firstly calculates the mass of the liquid to be detected according to the obtained induced pressure and the lever force arm proportion, then calculates the density of the liquid to be detected according to the volume of the added liquid to be detected, and finally calculates the viscosity of the detected liquid through a Kanazawa equation in combination with the change of the resonant frequency.

The object of the invention is thus achieved.

The liquid viscosity detector based on the QCM combines the lever principle, and detects the liquid quality while detecting the QCM frequency. Specifically, the QCM is packaged in a ring shape on the surface, and the liquid detection pool and the center of a piezoelectric quartz wafer form a liquid detection pool for containing various liquids to be detected. The integral crystal support is connected with the QCM electrode to provide electric conduction, and the support rod provides support for the QCM support and is a fulcrum of the lever. The lever principle can amplify the liquid with less liquid and less mass. The lower surface of the detection bar is covered with a pressure detection sensor, so that the detection circuit calculates the density of the liquid to be detected according to the obtained induction pressure and the volume of the liquid to be detected, and finally calculates the viscosity of the liquid to be detected by combining the change of the resonance frequency through a Kanazawa equation. Therefore, the lever principle is adopted for mass measurement, so that the liquid quantity is less, and meanwhile, the density and the resonant frequency can be measured simultaneously, the detection is convenient, and the operation is simple.

Drawings

FIG. 1 is a schematic diagram of the packaging assembly of a QCM sensor for a QCM-based liquid viscosity detector according to the present invention;

FIG. 2 is a schematic diagram showing the overall structure of the QCM-based liquid viscosity detector of the present invention.

Detailed Description

The following description of the embodiments of the present invention is provided in order to better understand the present invention for those skilled in the art with reference to the accompanying drawings. It is to be expressly noted that in the following description, a detailed description of known functions and designs will be omitted when it may obscure the subject matter of the present invention.

FIG. 1 is a schematic diagram of the packaging assembly of a QCM sensor for a QCM-based fluid viscosity detector according to the present invention.

In this embodiment, as shown in fig. 1, the QCM sensor is ring-packaged, and then its left and right outer edges are fixedly connected to the wafer integrated holder, which is connected to the upper and lower electrodes of the QCM sensor through the electrode leads of the upper and lower electrodes, respectively, thus forming a QCM sensor package assembly. Specifically, as shown in fig. 1, the QCM sensor package assembly includes:

the QCM sensor comprises a piezoelectric quartz wafer 11, an upper electrode 12 (detection electrode) and a lower electrode 13, wherein the piezoelectric quartz wafer 11 is circular, the diameter of the piezoelectric quartz wafer is D, the upper electrode 12 is circular sheet-shaped, the diameter of the upper electrode is n, the upper electrode is used as the detection electrode and covers the upper part of the piezoelectric quartz wafer 11, the lower electrode 13 is also circular sheet-shaped, the diameter of the lower electrode is m, and the lower electrode is used as a grounding electrode and covers the lower part of the piezoelectric quartz wafer 11.

The outer diameter and the inner diameter of the columnar ring 14 are respectively D and D, the thickness of the columnar ring is h, the columnar ring is aligned with the circle center of the piezoelectric quartz wafer 11 and used for carrying out annular packaging on the upper surface of the QCM sensor, the upper electrode 12 is placed in the columnar ring, and the columnar ring and the upper surface of the piezoelectric quartz wafer 11 form a liquid detection pool which is used for containing various liquids to be detected.

Wafer monolith support 17, including two spinal branch poles that length is L, two spinal branch poles parallel alignment, the front end respectively with QCM sensor's left and right outward flange fixed connection, provide the physics for the QCM sensor and support.

Electrode leads 16 and 15 of the upper electrode and the lower electrode are respectively connected with the upper electrode 12 and the lower electrode 13 and then respectively connected to the supporting rods at the left outer edge and the right outer edge of the QCM sensor, and the wafer integral support 17 is a conductor and provides electric conduction for the QCM sensor.

FIG. 2 is a schematic diagram showing the overall structure of the QCM-based liquid viscosity detector of the present invention.

In this embodiment, as shown in fig. 2, the QCM-based liquid viscosity monitor of the present invention includes, in addition to the QCM sensor package, further including:

and the supporting rod 21 is perpendicular to the wafer integrated bracket 17, the wafer integrated bracket 17 is placed on the supporting rod 21, the supporting rod 21 provides support for the wafer integrated bracket 17 and forms a lever, and the supporting rod 21 is a fulcrum of the lever.

The lower surfaces of the two detection rods 22 are covered with pressure detection sensors 23, and the rear ends of the two support rods of the wafer integral support 17 are respectively arranged below the detection rods 22 and are in contact with the pressure detection sensors 23.

For the wafer integral support 17, the distance between the support rod 21 and the detection rod 22 is L2 which is less than or equal to half of the length L of the wafer support, namely the lever power arm L1 is greater than the resistance arm L2, so that the wafer integral support, the support rod and the detection rod form a lever system. Preferably, lever power arm L1 is twice as long as resistance arm L2.

A detection circuit 25 connected to the rear ends of the two support rods of the wafer integrated holder 17, wherein the detection circuit 25 drives the QCM sensor to obtain the resonant frequency thereof, and meanwhile, the detection circuit 25 is connected to the pressure detection sensors 23 covered on the lower surfaces of the two detection rods 22, and the detection circuit 25 drives the pressure sensors 23 to obtain the pressure sensed by the pressure sensors; the connection is made by a set of wires 24. The central processor in the detection circuit 25 firstly calculates the mass of the liquid to be detected according to the obtained induction pressure and the lever arm ratio, then calculates the density of the liquid to be detected according to the volume of the added liquid to be detected, and finally calculates the viscosity of the liquid to be detected by combining the change of the resonance frequency through a Kanazawa equation and displays the viscosity through a display device.

The wafer monolith support 17 in the present invention not only provides a lever support for the entire QCM sensor package assembly, but also provides a conductive function. The columnar ring 14 and the upper surface of the piezoelectric quartz wafer 11 form a liquid detection pool, and a holding space is provided for detecting liquid to be detected.

The QCM sensor package assembly is inserted into the instrument by gripping the wafer monolith support 17 with tweezers, taking note that the wafer monolith support 17 is carried on the support bar 21, and the rear ends of the two support bars of the wafer monolith support 17 are respectively placed under the detection bar 22 and in contact with the pressure detection sensor 23 to form a lever state, wherein the resistance arm L2 is smaller than the lever power arm L1 to amplify the weight of the liquid to be measured.

QCM sensor encapsulation subassembly inserts the back, and instrument automatic initialization accomplishes a series of initial detection and shows ready, and this process is avoided QCM sensor encapsulation subassembly to insert some problems such as unstable contact failure, if show abnormal then need plug QCM sensor encapsulation subassembly again, probably QCM sensor encapsulation subassembly problem need be changed QCM sensor encapsulation subassembly when special.

And after all the liquid is ready, a micro-pipetting gun or other pipetting equipment is used for dripping a fixed amount of the liquid to be detected in the detection pool, wherein the liquid can completely cover the bottom area of the liquid detection pool. The volume of liquid added is entered on the display device. After the central processing unit in the detection circuit 254 acquires the quartz crystal resonant frequency and the pressure sensor value before and after loading the liquid to be detected, corresponding processing is performed to calculate the viscosity of the liquid to be detected and the viscosity is sent to the display device for display, and at the moment, the measurement is completed, and the QCM sensor packaging assembly can be carefully pulled out and thrown into a corresponding garbage can. The whole instrument forms a whole, and QCM sensor encapsulation subassembly plug-and-play. The whole operation process is simple, quick and short in time consumption.

Although illustrative embodiments of the present invention have been described above to facilitate the understanding of the present invention by those skilled in the art, it should be understood that the present invention is not limited to the scope of the embodiments, and various changes may be made apparent to those skilled in the art as long as they are within the spirit and scope of the present invention as defined and defined by the appended claims, and all matters of the invention which utilize the inventive concepts are protected.