CN217877926U - Portable liquid small flow standard flow measuring device - Google Patents

Abstract

The portable liquid small flow standard flow measuring device is characterized in that a testing component and a display component are integrated in a box body; the testing assembly comprises a processing module, a testing pipeline, a light emitting module, a light receiving module and a display assembly, wherein the light emitting module and the light receiving module are respectively positioned at two sides of the testing pipeline and are oppositely arranged; the light receiving module transmits the received signals to the processing module, and the processing module transmits the signals to the display component; the device of the utility model can meet the requirements of calibration and verification of various transparent liquids with different flow directions under small flow; during the measurement, the device can not cause the disturbance to the flow, and the test is more accurate reliable, and simultaneously, whole device work efficiency is high, degree of automation is high, and it is more convenient to use.

Description

Portable liquid small flow standard flow measuring device

technical field

The utility model belongs to the technical field of small liquid flow measuring devices, in particular to a portable standard flow measuring device for small liquid flow.

Background technique

More and more industries such as chip semiconductor manufacturing, bioengineering, pharmaceutical and chemical industry need to carry out small flow of liquid. Small flow of liquid often means that the flow rate is below 5ml/h.

In the prior art, there is a preparation device with small liquid flow rate recorded, for example, the patent number is: 201811052039.1, the patent name is: an ultra-small flow standard device based on linear expansion coefficient; the patentee is: Zhejiang Metrology Research A patent document of the Institute) discloses a technical solution for using the linear expansion characteristics of the working fluid and the characteristics that the volume of the liquid chamber does not change with the temperature to precisely control the temperature of the constant temperature water tank, thereby generating a small flow rate with the unit volume of the working fluid.

However, the detection of small flow of liquid has always been a pain point. The existing technology has high requirements for online measurement technology of small flow. Not only must the measurement be accurate, but it must also meet the measurement needs of the experimental site.

Researchers have conducted a lot of research to provide small flow measurement. At present, most of the small flow devices are piston-type, that is, the volume of the liquid is measured by the distance moved by the piston.

There are also devices that use high-precision electronic scales for small flow measurement. For example, the Concept of a New Primary Standard for Liquid Flow Measurement at PTBBraunschweig developed a set of flow standard devices using the static mass method.

But present device generally has two problems:

One is: the volume is large and not easy to move. Because the device includes structures such as pistons, the device cannot be used as a calibration device on the experimental site;

The second is: the reciprocating movement of the piston and the long-term work of the electronic scale will be affected by temperature and pressure. The geared motor and the processing accuracy of the piston will all affect the measurement accuracy of small flow, especially the measurement error under small flow and small flow. The impact is very noticeable. Therefore, the traditional metering method is subject to various restrictions, and cannot be well used for on-site metering of small flows.

Contents of the invention

The utility model aims to provide a portable liquid small flow standard flow measuring device with simple structure, good use effect and high accuracy.

In order to solve the above technical problems, the utility model provides the following technical solutions: a portable liquid small flow standard flow measuring device, including a box body and a test component and a display component integrated in the box; the test component includes a processing module, a test pipeline, a light emitting The module and the light-receiving module, the light-emitting module and the light-receiving module are respectively located on both sides of the test pipe, and they are set opposite to each other; the light-receiving module transmits the received signal to the processing module, and the processing module transmits the signal to the display component.

The light-emitting module includes an array of LED light-emitting diodes; the light-receiving module includes a plurality of photodiodes.

The test pipe is a transparent pipe, and the light transmittance of the transparent pipe is 92%.

The processing module includes a trigger circuit, an amplifying circuit, and a CPLD processor; the light-receiving module transmits the received optical signal to the trigger circuit, and the signal output end of the trigger circuit is connected to the amplifying circuit and the CPLD processor in sequence.

The trigger circuit includes a voltage comparator, a first compensation capacitor, a second compensation capacitor and an RC circuit; the CCD array includes a plurality of photodiodes connected in parallel; the anodes of each photodiode are grounded, and the cathodes of each photodiode are connected to the inverting phase of the voltage comparator The input terminal, the noninverting input terminal of the voltage comparator is grounded; the first compensation capacitor is connected between the inverting input terminal and the output terminal of the voltage comparator; the output terminal of the voltage comparator is connected to the RC circuit; the inverting input terminal of the voltage comparator is connected to the RC circuit; The second compensation capacitor and the compensation resistor connected in parallel are connected between the RC circuits.

The amplifying circuit includes an operational amplifier and an instrumentation amplifier. The noninverting input terminal of the operational amplifier is connected to the signal output terminal of the photoelectric sensor through the first capacitor, and the noninverting input terminal of the operational amplifier is also grounded through the first resistor; the inverting input terminal of the operational amplifier is grounded through the second capacitor. The resistor is connected to the output terminal of the operational amplifier; the output terminal of the operational amplifier is connected to the non-inverting input terminal of the instrumentation amplifier through the fifth capacitor; the inverting input terminal of the instrumentation amplifier is grounded through the fifth resistor; the output terminal of the instrumentation amplifier is connected to the CPLD processor.

Also includes a driving circuit, the driving circuit includes a first field effect transistor M1, a second field effect transistor, a first protection diode, a second protection diode, a first resistor and a second resistor; the signal output terminal of the CPLD processor is connected to the first field The G pole of the effect transistor M1, the G pole of the second field effect transistor, and the first end of the first resistor; the second end of the first resistor is grounded; the S pole of the first field effect transistor M1 is connected to a DC voltage; the first field effect The D pole of the tube M1 is connected to the first end of the second resistor, the second end of the second resistor is connected to the D pole of the second field effect transistor, and the S pole of the second field effect transistor is grounded; the anode of the first protection diode is connected to the first The D pole of the field effect transistor M1, the cathode of the first protection diode is connected to the S pole of the first field effect transistor M1; the anode of the second protection diode is connected to the S pole of the second field effect transistor, and the cathode of the second protection diode is connected to the second The D pole of the field effect transistor, and the D pole of the second field effect transistor are connected to the output line.

The display component includes a tablet computer, the CPLD processor is connected with a wireless network card, and the CPLD processor transmits the signal output by the driving circuit to the tablet computer through the wireless network card for display.

The model of the CPLD processor is 7128SLC84-15.

The display component includes a display module, and the output line of the CPLD processor is connected to the display module.

Through the above technical solutions, the technical effects of the utility model are as follows: 1. In this embodiment, the test assembly is integrated in the box, and the device is movable, which greatly facilitates the online calibration and measurement of small flow; 2. The device can Realize the calibration and verification requirements of transparent liquids under small flow rates in different flow directions; high work efficiency, more accurate and reliable testing; 3. Adopt photoelectric non-contact type, which will not disturb the liquid, and at the same time, have a long service life and reduce maintenance costs in the later period Low.

Description of drawings

Fig. 1 is the structural representation of the utility model;

Fig. 2 is the CPLD processor circuit principle diagram of embodiment 1;

Figure 3 is a schematic diagram of the trigger circuit;

Fig. 4 is a schematic diagram of the amplification circuit;

Figure 5 is a schematic diagram of the drive circuit;

FIG. 6 is a schematic circuit diagram of Embodiment 2.

Detailed ways

Embodiment 1, a portable liquid small flow rate standard flow measuring device, as shown in Figures 1 to 5, includes a box body, the bottom of the box body is connected with a base, the base can be lifted, and the bottom surface of the base is provided with universal wheels; the upper surface of the box body is provided with With handle, easy to move and carry.

A test component is integrated in the box, and the test component is used to detect the flow information. When it needs to be used, the box body is opened so that the test components are exposed. In this embodiment, no improvement to the box itself is involved, as long as it can accommodate the test components, for example, a box in the shape of a cuboid. In the accompanying drawings, there is no accompanying drawing showing the specific structure of the box body.

The test assembly is used to detect the small flow of liquid. In this embodiment, the test assembly includes a processing module, a test pipe 14 , a light emitting module 11 and a light receiving module 12 .

The light-emitting module 11 and the light-receiving module 12 are respectively located on two sides of the test pipe 14, and they are set opposite to each other; the light-receiving module 12 transmits the received signal to the processing module. The photoelectric measurement of flow information is realized by setting the light-emitting module 11 and the light-receiving module 12, and the data is collected without contact, with little disturbance to the flow and higher accuracy.

The test pipeline 14 used in this embodiment is a transparent pipeline, and the light transmittance of the transparent pipeline is 92%.

The light-emitting module 11 includes an LED light-emitting diode array, and the LED light-emitting diode array includes a plurality of light-emitting diodes, each light-emitting diode is connected in parallel, and the anode of each light-emitting diode is grounded, and the cathode of each light-emitting diode can be grounded through a grounding resistor.

The light receiving module 12 includes a photodiode array connected in parallel, and each light emitting diode is arranged opposite to each photodiode.

The light signal sent by the light emitting module is received by the light receiving module after passing through the transparent pipe, and the light receiving module transmits the received light signal to the processing module.

The processing module includes a trigger circuit 131, and the trigger circuit 131 converts an optical signal into a current signal.

During measurement, the light transmittance above the liquid surface and below the liquid surface in the test pipe 14 is different, and the trigger circuit generates light signals reflecting different light intensities and converts them into electrical signals.

The trigger circuit 131 includes a voltage comparator U8, a first compensation capacitor Cf1, a second compensation capacitor Cf2, and an RC circuit. The signal output terminal of the light receiving module 12 is connected to the signal input terminal of the trigger circuit, and the optical signal is converted into an electrical signal through the trigger circuit. making it easy to measure.

The light receiving module 12 has two photodiodes in total, the first photodiode D3 and the second photodiode D4, the anodes of the first photodiode D3 and the second photodiode D4 are all grounded, and the cathodes of the first photodiode D3 and the second photodiode D4 are grounded. Connect the inverting input of the voltage comparator U8, and the non-inverting input of the voltage comparator U8 is grounded. A first compensation capacitor Cf1 is connected between the inverting input terminal and the output terminal of the voltage comparator U8.

The output terminal of the voltage comparator U8 is connected to the sixth resistor R6, the first terminal of the sixth resistor R6 is connected to the output terminal of the voltage comparator U8, and the second terminal of the sixth resistor R6 is grounded through the eighth capacitor C8. At the same time, the second terminal of the sixth resistor R6 serves as the output terminal of the trigger circuit.

In this embodiment, the sixth resistor R6 and the eighth capacitor C8 form an RC circuit, which can filter the output signal of the trigger circuit.

In addition, in order to improve the triggering effect, a second compensation capacitor Cf2 and a compensation resistor Rf are connected in parallel between the inverting input terminal of the voltage comparator U8 and the second terminal of the sixth resistor R6.

The signal output end of the trigger circuit 131 is connected to the amplifying circuit 132. Since the flow signal obtained by the trigger circuit 131 is very weak, it will be submerged by noise when it is directly output to the subsequent circuit. Therefore, the amplifying circuit 132 is set to amplify the weak flow signal measured. , so that the output signal has good linearity and anti-interference ability.

The amplifying circuit 132 includes a circuit board, an operational amplifier U4 and an instrumentation amplifier (model INA103) U5 integrated on the circuit board.

In this embodiment, the instrumentation amplifier of the type INA103 is selected, which integrates a common operational amplifier inside. It inherits the performance of the common operational amplifier and also has advantages that the common operational amplifier does not have. If there is a very high input impedance, it is generally not lower than 10 ⁹ ohms; it has a good common-mode rejection ratio, generally not lower than 50dB, which can well suppress common-mode signals; it has a high gain bandwidth and can realize The gain is adjustable from 1 to 1000.

The circuit board selected for the amplifying circuit needs to use a high-insulation circuit board with low leakage current. In order to ensure the normal use of the operational amplifier U4 and the instrumentation amplifier U5, the first power supply circuit is connected to the first power supply terminal of the operational amplifier U4 and the instrumentation amplifier U5; the second power supply terminal of the operational amplifier U4 and the instrumentation amplifier U5 is connected There is a second power supply circuit.

Wherein, the first power supply circuit includes a first power conversion chip U6 (type 7812), the input terminal of the first power conversion chip U6 is connected to a DC power supply, and the input terminal and output terminal of the first power conversion chip U6 are respectively passed through the sixth capacitor C6 and the seventh capacitor C7 are grounded, the output end of the first power conversion chip U6 is the first power end of the operational amplifier U4 and the instrumentation amplifier U5.

The second power supply circuit includes a second power conversion chip U7 (model 7912), the input terminal of the second power conversion chip U7 is connected to a DC power supply, and the input terminal and output terminal of the second power conversion chip U7 are connected through the second capacitor C2 and the The three capacitors C3 are grounded, the output end of the second power conversion chip U7 is the second power end of the operational amplifier U4 and the instrumentation amplifier U5.

The non-inverting input end of the operational amplifier U4 is connected to the second end of the sixth resistor R6 of the trigger circuit through the first capacitor C1. The noninverting input terminal of the operational amplifier U4 is also grounded through the first resistor R1; the inverting input terminal of the operational amplifier U4 is connected to the output terminal of the operational amplifier U4 through the second resistor R2; the inverting input terminal of the operational amplifier U4 is also connected through the third resistor R3 grounded.

The output terminal of the operational amplifier U4 is connected to the non-inverting input terminal of the instrumentation amplifier U5 through the fifth capacitor C5; the non-inverting input terminal of the instrumentation amplifier U5 is grounded through the fourth resistor R4, and at the same time, the inverting input terminal of the instrumentation amplifier U5 is grounded through the fifth resistor R5 ; The output terminal of the instrumentation amplifier U5 is connected to the I/O port of the CPLD processor U1.

Wherein, the first resistor R1 , the second resistor R2 , the third resistor R3 , the fourth resistor R4 and the fifth resistor R5 are metal film resistors. The eighth capacitor C8 is a bile capacitor or a ceramic capacitor, and the wire connecting the trigger circuit and the amplifying circuit is a shielded cable as short as possible.

The model of the CPLD processor U1 is 7128SLC84-15. The CPLD processor U1 performs digital filtering on the received signal. The digital filtering program is a mature existing program. This embodiment does not involve the improvement of the digital filtering program.

The signal output terminal of the CPLD processor U1 is connected to a driving circuit, and the driving circuit improves the driving capability of the signal so that the output signal does not attenuate after transmission.

The driving circuit 134 includes a first field effect transistor M1, a second field effect transistor M2, a first protection diode D1, a second protection diode D2, a seventh resistor R7 and an eighth resistor R8; the signal output terminal of the CPLD processor U1 is connected to the first The G pole of the field effect transistor M1, the G pole of the second field effect transistor M2, the first end of the sixth resistor R6; the second end of the seventh resistor R7 is grounded; the S pole of the first field effect transistor M1 is connected to the DC voltage ; The D pole of the first field effect transistor M1 is connected to the first end of the eighth resistor 8, the second end of the eighth resistor 8 is connected to the D pole of the second field effect transistor M2, and the S pole of the second field effect transistor is grounded; The anode of a protection diode D1 is connected to the D pole of the first field effect transistor M1, the cathode of the first protection diode D1 is connected to the S pole of the first field effect transistor M1; the anode of the second protection diode D2 is connected to the second field effect transistor M2 The S pole and the cathode of the second protection diode D2 are connected to the D pole of the second field effect transistor M2.

For the convenience of display, a wireless network card U2 (model CS8900) is connected to the CPLD processor U1, and the wireless network card U2 wirelessly transmits signals to the display components. The display component includes a tablet computer, and the tablet computer displays the collected traffic information. It is a mature prior art that the CPLD processor U1 transmits the signal to the tablet computer for display through the wireless network card U2, and its implementation will not be repeated in this embodiment.

The method of use is: open the device, the liquid enters the test pipe 14, the light-emitting module works, the light passes through the test pipe 14 and is received by the light-receiving module, and the light-receiving module transmits the received light signal to the trigger circuit, and the trigger circuit transmits the light signal It is converted into a pulse signal that is changed by the change of light intensity, the pulse signal is amplified by the amplifier circuit, and the amplified signal is sent to the CPLD processor U1, and the CPLD processor U1 uses the existing method to digitally filter the signal; then, the output signal To the driving circuit, through the processing of the driving circuit to avoid the loss and loss in the subsequent transmission process, after passing through the driving circuit, the signal is transmitted to the tablet computer through the wireless network card U2, and then displayed on the tablet computer display screen. It is a mature prior art that the CPLD processor U1 transmits the signal to the tablet computer for display, and the specific implementation will not be repeated in this embodiment.

Embodiment 2. The difference between this embodiment and Embodiment 1 is that, as shown in FIG. 6 , the display component includes a display module U3, and the IO port of the CPLD processor U1 is connected to the display module U3 (model LCD1602). The signal output from the CPLD processor U1 is displayed on the display screen of the display module U3.

The device described in the utility model has a movable box body, which greatly facilitates the online calibration and measurement of small flow liquids, can meet the calibration and verification requirements of various transparent liquids under small flow rates, and has high work efficiency; at the same time, it will not Disturbance testing of liquids is more accurate and reliable.

Claims (10)

1. Portable liquid low flow standard flow measuring device, its characterized in that: the device comprises a box body, wherein a test component and a display component are integrated in the box body; the testing assembly comprises a processing module, a testing pipeline, a light emitting module, a light receiving module and a display assembly, wherein the light emitting module and the light receiving module are respectively positioned at two sides of the testing pipeline and are oppositely arranged; the light receiving module transmits the received signal to the processing module, and the processing module transmits the signal to the display component.

2. The portable liquid low flow standard flow measuring device of claim 1, wherein: the light emitting module comprises an LED light emitting diode array; the light receiving module includes a plurality of photodiodes.

3. The portable liquid low flow standard flow measuring device of claim 2, wherein: the test tube was a transparent tube having a light transmittance of 92%.

4. A portable liquid small flow standard flow measurement device as defined in claim 3, wherein: the processing module comprises a trigger circuit, an amplifying circuit and a CPLD processor; the light receiving module transmits the received optical signal to the trigger circuit, the signal output end of the trigger circuit is sequentially connected with the amplifying circuit and the CPLD processor, and the CPLD processor outputs the signal to the display component.

5. The portable liquid low flow standard flow measuring device of claim 4, wherein: the trigger circuit comprises a voltage comparator, a first compensation capacitor, a second compensation capacitor and an RC circuit; the CCD array comprises a plurality of parallel photodiodes; the positive electrode of each photodiode is grounded, the negative electrode of each photodiode is connected with the inverting input end of a voltage comparator, and the non-inverting input end of the voltage comparator is grounded; a first compensation capacitor is connected between the inverting input end and the output end of the voltage comparator; the output end of the voltage comparator is connected with the RC circuit; and a second compensation capacitor and a compensation resistor which are connected in parallel are connected between the inverting input end of the voltage comparator and the RC circuit.

6. The portable liquid small flow standard flow measurement device of claim 5, wherein: the amplifying circuit comprises an operational amplifier and an instrument amplifier, wherein the non-inverting input end of the operational amplifier is connected with the signal output end of the photoelectric sensor through a first capacitor, and the non-inverting input end of the operational amplifier is grounded through a first resistor; the inverting input end of the operational amplifier is connected with the output end of the operational amplifier through a second resistor; the output end of the operational amplifier is connected with the non-inverting input end of the instrumentation amplifier through a fifth capacitor; the inverting input end of the instrumentation amplifier is grounded through a fifth resistor; the output end of the instrument amplifier is connected with the CPLD processor.

7. The portable liquid small flow standard flow measurement device of claim 6, wherein: the driving circuit comprises a first field effect transistor, a second field effect transistor, a first protection diode, a second protection diode, a seventh resistor and an eighth resistor; the signal output end of the CPLD processor is connected with the G pole of the first field effect tube M1, the G pole of the second field effect tube and the first end of the seventh resistor; the second end of the seventh resistor is grounded; the S pole of the first field effect transistor M1 is connected with direct current voltage; the D pole of the first field effect transistor M1 is connected with the first end of the eighth resistor, the second end of the eighth resistor is connected with the D pole of the second field effect transistor, and the S pole of the second field effect transistor is grounded; the anode of the first protection diode is connected with the D pole of the first field effect transistor M1, and the cathode of the first protection diode is connected with the S pole of the first field effect transistor M1; the anode of the second protection diode is connected with the S pole of the second field effect transistor, the cathode of the second protection diode is connected with the D pole of the second field effect transistor, and the D pole of the second field effect transistor is connected with the output line.

8. The portable liquid small flow standard flow measurement device of claim 7, wherein: the display component comprises a tablet personal computer, a wireless network card is connected to the CPLD processor, and the CPLD processor wirelessly transmits the output signal of the driving circuit to the tablet personal computer for display through the wireless network card.

9. A portable liquid low flow standard flow measuring device according to any one of claims 1 to 8, wherein: the model of the CPLD processor is 7128SLC84-15.

10. The portable liquid small flow standard flow measurement device of claim 6, wherein: the display component comprises a display module, and an output line of the CPLD processor is connected with the display module.

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