Device for measuring average molecular weight of mixed gas

Abstract

The utility model relates to a device for measuring the average molecular weight of mixed gas, which comprises a DC / DC (Direct Current / Direct Current) boosting module, a driving signal module, a channel switching control module, an ultrasonic transducer, an ultrasonic echo signal amplification module, an ultrasonic echo signal filtering processing module and a microprocessor, the ultrasonic transducers are installed on the upstream pipe wall and the downstream pipe wall in the flowing direction of fluid in a pipeline respectively and are installed opposite to the axis of the pipeline, and an included angle is formed between the ultrasonic transducers and the axis of the pipeline, and the molecular weight of a measured medium is indirectly measured through an ultrasonic sensor, a temperature sensor and a pressure sensor which are arranged in the ultrasonic flowmeter. The single-ended signal is converted into the differential signal, compared with a common amplification mode of converting the single-ended signal into the single-ended signal, the anti-interference capability of the signal is enhanced, the signal transmission distance is farther through the driving signal module, the precision of measured data is improved through the channel switching control module, the cost is low, and the measurement is accurate.

Description

TECHNICAL FIELD

[0001] The utility model relates to ultrasonic flow measuring equipment technical field especially relates to a device of measuring mixed gas average molecular weight. BACKGROUND

[0002] Gas component is a main parameter in energy measurement, and the current gas component measurement mainly uses chromatograph measurement method. The chromatograph separates by bringing gas into different chromatographic columns, and then detects the concentration of each component through a detector. The whole process is a measurement cycle, which may take several minutes. Chromatography has many advantages, such as high separation efficiency, high detection sensitivity, good selectivity, etc. However, the chromatograph is expensive and has low cost performance.

[0003] Ultrasonic measurement has many advantages, such as non-contact measurement, high precision, good stability, etc. Due to these advantages of ultrasonic measurement, more and more flow measurement fields have the application of ultrasonic flowmeter. However, the signal is weak in the process of measuring the average molecular weight of mixed gas by conventional ultrasonic measurement, which is easily disturbed, and the propagation distance is limited, which may cause inaccurate measurement data. SUMMARY

[0004] The utility model provides a device of measuring mixed gas average molecular weight, through ultrasonic transducer indirect measurement mixed gas's average molecular weight, through ultrasonic echo signal amplification module, convert single ended signal into differential signal, compare with the amplification mode of ordinary single ended signal conversion single ended signal, strengthen the anti -interference ability of signal, and through drive signal module makes signal transmission distance farther, through channel switching control module improves the precision of measurement data, low in cost, accurate measurement.

[0005] In order to achieve the above purpose, the utility model adopts the following technical scheme:

[0006] The utility model provides a device for measuring the average molecular weight of mixed gas, which comprises a DC / DC booster module, a driving signal module, a channel switching control module, an ultrasonic transducer, an ultrasonic echo signal amplification module, an ultrasonic echo signal filtering processing module and a microprocessor. The ultrasonic transducers are installed on the upper and lower stream walls of the pipeline fluid flow direction and are opposite to the pipeline axis. The voltage output pin of the DC / DC booster module is connected to the voltage input end of the driving signal module. The IO pin of the driving signal module is connected to the output pin of the microprocessor. The control output pin of the driving signal module is connected to the input pin of the channel switching control module. The IO pin of the channel switching control module is connected to the two ultrasonic transducers. The output pin of the channel switching control module is connected to the input pin of the ultrasonic echo signal amplification module. The output pin of the ultrasonic echo signal amplification module is connected to the input pin of the ultrasonic echo signal filtering processing module. The output pin of the ultrasonic echo signal filtering processing module is connected to the input pin of the microprocessor.

[0007] The input signal of the ultrasonic echo signal amplification module is a single-ended signal, and the output signal is a differential signal. The signal pin is connected to the ultrasonic echo signal filtering processing module.

[0008] Further, the channel switching control module is one or more, and the number of the channel switching control modules is matched with the number of the ultrasonic transducers.

[0009] Further, the receiving end of the ultrasonic echo signal amplification module is connected to the output end of the channel switching control module, and a TVS diode, a series inductor and a capacitor are connected to the ground on the connection circuit.

[0010] Further, the included angle between the ultrasonic transducer and the pipeline axis is in the range of 30-60°.

[0011] Compared with the prior art, the utility model has the following beneficial effects:

[0012] 1) The ultrasonic transducer, the temperature sensor and the pressure sensor are built in the ultrasonic flowmeter. There is a quantitative relationship between the propagation speed of ultrasonic waves in the gas and the molecular weight of the gas, so the molecular weight of the measured medium can be indirectly measured.

[0013] 2) In the ultrasonic echo signal amplification module, the single-ended signal is converted into a differential signal. Compared with the common single-ended signal amplification mode, the signal anti-interference ability is enhanced.

[0014] 2) In the channel switching control module, the number of channels can be increased or decreased according to the actual situation, so as to meet different requirements.

[0015] 3) Only the ultrasonic transducer is used to measure the molecular weight, and compared with other molecular weight measuring devices, the utility model has high cost performance.BRIEF DESCRIPTION OF DRAWINGS BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is the structural diagram of the utility model.

[0017] Figure 2 is the position diagram of the ultrasonic transducer A and the ultrasonic transducer B.

[0018] Figure 3 is the wiring diagram of the DC / DC boost module.

[0019] Figure 4 is the wiring diagram of the drive signal module.

[0020] Figure 5 is the wiring diagram of the channel switching control module.

[0021] Figure 6 is the wiring diagram of the ultrasonic echo signal amplification module.

[0022] Figure 7 is the wiring diagram of the ultrasonic echo signal filtering processing module.

[0023] Fig. 1. ultrasonic transducer A 2. ultrasonic transducer B DETAILED DESCRIPTION

[0024] The specific embodiments of the application will be further described in conjunction with the accompanying drawings:

[0025] See Figures 1-2 The utility model relates to a device for measuring the average molecular weight of mixed gas, comprising a DC / DC boost module, a drive signal module, a channel switching control module, an ultrasonic transducer, an ultrasonic echo signal amplification module, an ultrasonic echo signal filtering processing module and a microprocessor. The ultrasonic transducer comprises an ultrasonic transducer A1 and an ultrasonic transducer B2. The ultrasonic transducer A1 and the ultrasonic transducer B2 are installed on the upstream and downstream of the fluid flow direction of the pipeline. The ultrasonic transducer A1 and the ultrasonic transducer B2 are respectively arranged on the upstream and downstream pipe walls of the fluid flow direction of the pipeline. Each ultrasonic transducer can both emit and receive ultrasonic signals. The ultrasonic transducers are installed opposite to the pipeline axis and form an included angle with the pipeline axis in the range of 30-60°.

[0026] See Figure 3 The DC / DC boost module provides a higher voltage level for the ultrasonic drive signal. The input VCC+10V signal is boosted to VH_OUT output through the U12 chip. The DC / DC boost module pin VH_OUT is connected to the drive signal module voltage input end VH_OUT.

[0027] See Figure 4 , the drive signal module provides excitation pulse signal for ultrasonic transducer, theoretically the greater the amplitude of the excitation pulse signal, the farther the ultrasonic signal transmission distance generated by the transducer, the enable pin PWM_CS pin of the drive signal module is connected to the PWM_CS pin of the microprocessor, which controls whether the drive signal module outputs the drive signal, the drive signal pin of the drive signal module is connected to the pin PWM_SIG of the microprocessor which generates low voltage drive pulse signal, the drive module converts the low voltage drive pulse signal PWM_SIG into high voltage drive pulse signal TX_SIG with amplitude VH_OUT through U11 chip, and the signal output pin TX_SIG of the drive signal module is connected to the channel switching control module TX_SIG pin.

[0028] See Figure 5 , the channel switching control module controls the switching of different channels of ultrasonic waves and the switching of the transmitting and receiving directions of the transducers in the same channel, P5 is an ultrasonic transducer terminal, two ultrasonic transducers are connected to the P5 terminal, each ultrasonic transducer has two wires, a signal wire and a ground wire, the TX_CH1_SIG_AB pin and the TX_CH1_SIG_BA pin are respectively the signal wire pins of the two transducers, the function of the circuit is channel switching controlled by the microprocessor, the control pin CTRL_CH1_A2B of the microprocessor controls the enable, so that the drive pin TX_SIG is connected to the ultrasonic transducer pin TX_CH1_SIG_AB, and at the same time the TX_CH1_SIG_BA pin is connected to the pin USS_RCV, so that the ultrasonic transducer connected to the pin TX_CH1_SIG_AB is used as a transmitting ultrasonic transducer, and the ultrasonic transducer connected to the pin TX_CH1_SIG_BA is used as a receiving transducer to receive the ultrasonic signal emitted by the transmitting transducer, and the pin USS_RCV is connected to the ultrasonic echo signal amplification module; when the control pin CTRL_CH1_SIG_B2A of the microprocessor sends an enable signal, the drive pin TX_SIG is connected to the ultrasonic transducer pin TX_CH1_SIG_BA, and at the same time the TX_CH1_SIG_AB pin is connected to the pin USS_RCV, so that the ultrasonic transducer connected to the pin TX_CH1_SIG_BA is used as a transmitting ultrasonic transducer, and the ultrasonic transducer connected to the pin TX_CH1_SIG_AB is used as a receiving transducer to receive the ultrasonic signal emitted by the transmitting transducer, and the pin USS_RCV is connected to the ultrasonic echo signal amplification module; one channel switching control module can only connect two transducers, multiple ultrasonic transducers can be connected by using multiple channel switching modules, such as implementing 4 channels (8 transducers), etc., and using multiple channels can improve the accuracy of measurement data.

[0029] The ultrasonic transducer generates an ultrasonic signal, and the ultrasonic transducer emits the ultrasonic signal when an excitation pulse signal is applied to the ultrasonic transducer, and the emitted ultrasonic signal is received by a receiving transducer mounted on the same channel.

[0030] See Figure 6 Due to scattering, absorption and other factors of ultrasonic waves in the propagation process, the signals actually received by the receiving transducer are relatively small and weak, and thus it is generally necessary to amplify the received signals, the USS_RECV of the ultrasonic echo signal amplification module is connected to the echo signal pin of the channel switching control module, and the weak ultrasonic signal is amplified after the signal is processed by the chip U16 of the module, and the output signal after amplification is a differential signal, the pin is VGA_VOL and VGA_VOH, and the differential signal is connected to the VGA_VOL and VGA_VOH pins of the ultrasonic echo signal filtering processing module; the U16 adopts an AD8331ARQZ type chip, the INH pin of the U16 is connected to the resistance R16 and the TVS diode after being connected in series with the capacitor C61 and the inductor L9, the connection position of the resistance R16 and the TVS diode is connected to the ultrasonic echo signal amplification module, the continuity of the ultrasonic signal input into the ultrasonic echo signal amplification module is ensured; in the ultrasonic echo signal amplification module, the input single-ended signal is converted into a differential signal through the amplification module, the anti-interference ability is greatly enhanced, and part of the interference signals are also filtered out.

[0031] See Figure 7 Due to the fact that the propagation path of the ultrasonic wave is not an ideal environment, and due to the influence of various factors, the received ultrasonic echo signal will inevitably be mixed with some interference signals, and it is necessary to filter and process these signals, and the processed signals are sent to the microprocessor for signal acquisition and other processing, the differential signal after being amplified by the ultrasonic echo signal amplification module is connected to the REV_BAUD_A pin of the ultrasonic echo signal filtering processing module after being filtered, and the signal is collected and processed by the microprocessor, so that the sound velocity and other information are calculated.

[0032] The microprocessor is the core part of the sound velocity calculation, and controls each part of the sound velocity measurement module; the sound velocity is calculated inside the flowmeter.

[0033] The above examples are implemented on the premise of the technical scheme of the utility model, and detailed implementation modes and specific operation processes are given, but the protection scope of the utility model is not limited to the above examples. The methods used in the above examples are all conventional methods unless otherwise specified.

Claims

1. An apparatus for measuring the average molecular weight of a mixed gas, characterized by, The ultrasonic flowmeter comprises a DC / DC booster module, a driving signal module, a channel switching control module, an ultrasonic transducer, an ultrasonic echo signal amplification module, an ultrasonic echo signal filtering processing module and a microprocessor; the ultrasonic transducer is arranged on the upstream and downstream pipe walls of the fluid flow direction of the pipeline and is installed opposite to the pipeline axis; a voltage output pin of the DC / DC booster module is connected to a voltage input end of the driving signal module, an IO pin of the driving signal module is connected to an output pin of the microprocessor, a control output pin of the driving signal module is connected to an input pin of the channel switching control module, an IO pin of the channel switching control module is connected to two ultrasonic transducers, an output pin of the channel switching control module is connected to an input pin of the ultrasonic echo signal amplification module, an output pin of the ultrasonic echo signal amplification module is connected to an input pin of the ultrasonic echo signal filtering processing module, and an output pin of the ultrasonic echo signal filtering processing module is connected to an input pin of the microprocessor. An input signal of the ultrasonic echo signal amplification module is a single-ended signal, and an output signal is a differential signal, and the differential signal pin is connected to the ultrasonic echo signal filtering processing module.

2. The device for measuring the average molecular weight of a mixed gas according to claim 1, wherein The channel switching control module is one or more, and the number of the channel switching control modules is matched with the number of the ultrasonic transducers.

3. The device for measuring the average molecular weight of a mixed gas according to claim 1, wherein A receiving end of the ultrasonic echo signal amplification module is connected to an output end of the channel switching control module, and a TVS diode, a serial inductor and a capacitor are connected to the ground on a connection circuit.

4. The device for measuring the average molecular weight of a mixed gas according to claim 1, wherein An included angle between the ultrasonic transducer and the pipeline axis ranges from 30 to 60 degrees.

Images