KR100791319B1 - The ultrasonic doppler flowmeter for sewerage water - Google Patents

Abstract

The present invention relates to an ultrasonic Doppler flow meter for sewage pipe, more specifically, to measure the average flow rate of the fluid by the ultrasonic Doppler flow rate sensor, and to calculate the cross-sectional area of the fluid based on the water level measured by the pressure level sensor. A digital signal processor (DSP) processes these signals and multiplies the cross-sectional area of the measured fluid with the average flow rate to calculate the sewage flow rate in the sewer pipe. It's about a Doppler flowmeter.

Ultrasonic Doppler Flowmeter, Sewage Pipe, D.S.P, Full Pipe, Obesity Pipe

Description

The ultrasonic doppler flowmeter for sewerage water

1 is a principle diagram of obesity flow rate measurement by conventional ultrasonic flow rate measurement and water level measurement

2 is a flow rate measurement principle of the ultrasonic Doppler system for sewage pipe

Figure 3 is a block diagram of a conventional ultrasonic Doppler flow meter

Figure 4 is a block diagram of a conventional tubular ultrasonic Doppler flow meter

Figure 5 is a block diagram of the ultrasonic Doppler flow meter for sewage pipe according to the present invention

* Explanation of symbols for main parts of the drawings

DESCRIPTION OF SYMBOLS 1 Flowmeter 2 Flow measurement sensor 2a Pressure level sensor 2b Ultrasonic transmission sensor 2c Ultrasonic receiving sensor 3 Signal amplification and analog circuit 3a Water level signal amplifying circuit 3b Ultrasonic oscillation output circuit 3c Ultrasonic signal receiving amplification Circuit 4 DSP Signal Processing Unit 5 Main Processing Unit 6 TFT LCD Display Key Control Unit 7 Interface Unit 8 USB Port (USB) Memory 9: Automatic sensor cleaning device 10: Automatic compressed air generator for sensor cleaning

The present invention relates to a flow meter using the ultrasonic Doppler principle, more specifically, in measuring the flow rate of a fluid in a full or obese tube flow in a sewage pipe, the flow rate is measured using the ultrasonic Doppler principle and a pressure gauge is used. An ultrasonic Doppler flowmeter for sewer pipes, which measures the water level, calculates the flow area of the fluid, and calculates the volumetric volume of the sewage by calculating the average flow velocity and the flow area.

In general, the method of measuring the sewage flow rate in the sewage pipe and the method using an electromagnetic flow (Electro-Magnetic Flowmeter); Calculating a flow rate using devices for measuring point flow velocity at one or several points of the same flow section in the sewage pipe; A method of measuring flow rate by installing weir and flume in sewage pipes; A method of installing a diaphragm in the sewage pipe and calculating a flow rate by measuring a differential pressure generated therein; A method of calculating a flow rate by combining an ultrasonic time difference tachometer and a water level sensor; Flow rate measurement method using ultrasonic multi-line method, which calculates the flow rate by installing several ultrasonic time difference flow sensors on the outer wall of sewage pipe and separate measuring pipe, among them ultrasonic level meter and bottom of sewage pipe The most common method is to measure the sewage flow rate by combining the other water level measurement method and the ultrasonic Doppler flow rate sensor.

Conventionally, as a method for measuring the sewage flow rate of the sewer pipe in the obesity pipe state, as shown in Figure 1 for the measurement of the water level by the ultrasonic air propagation method and the flow rate of one or two or more places, such as the position of the lower point Yp of the sewer pipe Ultrasonic time difference method and ultrasonic Doppler type flow rate measuring sensor were installed to measure the flow rate and the flow rate was measured through their calculation.

However, in the above method, the flow rate sensor that measures the flow rate only measures the point flow rate Vp. Therefore, in order to increase the accuracy of the measurement flow rate, the multi-line method in which two or more flow rate sensors are installed must be used, and the flow rate measurement sensors are also installed in the sewer pipe. Or there was a problem in construction, such as the need to install a sewage pipe to make a measuring pipe with a separate flow rate measurement sensor.

Therefore, the ultrasonic flowmeters installed and used in the sewage pipes of the conventional digital circuits are also used in the case of the ultrasonic doppler flowmeter using the ultrasonic time difference method or the ultrasonic multi-line measurement method or the ultrasonic doppler flow rate measurement method. It is a method that processes signals about fluid flow rate only by digital logic circuits such as gate arrays, so it cannot efficiently process signals from fluids in sewer pipes, which causes errors in flow measurement. there was.

That is, the ultrasonic Doppler flowmeter for sewage pipe measures the average flow velocity of the fluid flow in the sewage pipe in the flow measurement sensor unit consisting of the Doppler flow rate sensor and the pressure level sensor, and the fluid pressure in the sewage pipe by the pressure level sensor After calculating the area, the flow rate is calculated by multiplying the average flow rate and the flow area of the fluid.The ultrasonic Doppler flow sensor, which measures the average flow rate of the ultrasonic flowmeter for sewage pipe, was first introduced by Christian Doppler in 1843. Based on the Doppler effect found, the relation for measuring the average flow velocity of fluid in sewer pipes by the Doppler effect is given by

Equation 1

As can be seen from Equation 1, the average flow velocity measurement of sewage flowing in the sewer pipe is a method of calculating the flow rate by measuring the ultrasonic Doppler frequency represented by particles flowing like sewage in the sewage based on the principle of ultrasonic Doppler. By measuring the velocity of numerous particles flowing together in the sewage, the velocity of flow in the area detected by the ultrasonic Doppler sensor must be calculated.

Ultrasonic waves used in the ultrasonic Doppler flow rate sensor are roughly delivered in a cone shape as shown in FIG. 2, and these flow rate sensors are mostly installed at the bottom of the sewage pipe to measure the flow rate of sewage. The flow rate formula of 1 is based on the ultrasonic Doppler flow velocity measurement single particle model, but there are many particles in the real sewage and the ultrasonic Doppler is moving at different speeds according to the fluid profile in different parts of the ultrasonic zone. Signal processing is measured in such a way that the average is calculated over the measured frequencies.

Therefore, the conventional analog signal processing method as shown in FIG. 3 or the method using an individual digital circuit can greatly depend on the intensity of the scattered and reflected ultrasonic Doppler signal, and also when calculating the average flow rate according to the flow rate distribution. Relying on low-pass filtering methods, many errors can be made in practice.

On the other hand, Figure 4 is a general block diagram of a conventional ultrasonic Doppler flow meter when the ultrasonic wave oscillated from the ultrasonic oscillator is sent to the sewage flow fluid in the sewage pipe through the ultrasonic transmitter of the sensor through a transmission circuit in the flow particles in the sewage fluid fluid Ultrasonic Doppler at the Frequency Counter through the Low Pass Filter, which is scattered and reflected, mixed and detected together with the ultrasonic oscillation frequency at the oscillator through the ultrasonic receiver amplifier of the sensor and the ultrasonic receiver amplifier circuit of the flow converter. It is composed of the basic principle of outputting the frequency deviation according to the measured flow rate.In this case, when the flow rate is measured using the flow rate relation according to the ultrasonic Doppler principle of Equation 2 below, the speed of sound changes according to the temperature of the sewage. Function as a function to measure the temperature Jueoyaman and yet been received and each of the scattering reflection of the ultrasonic Doppler frequency from the number of particles present in the actual wastewater flow becomes and hence it is possible to accept the expression (2).

Therefore, in the case of measuring the sewage flow rate in an actual sewage pipe, it is necessary to observe the spectrum of each ultrasonic Doppler frequency scattered and reflected from the flow fluid, and calculate the flow rate by using arithmetic mean or statistical mean in real time.

Equation 2

From here

: 비례 상수

: Proportional constant

: 각각의 입자로 부터의 도플러 주파수

= Doppler frequency from each particle

: 초음파조사 영역 내의 입자 집합을 고려한 파워 스펙트럼 밀도

: Power spectral density considering particle set in ultrasonic irradiation region

을 측정함으로써 유속

를 계측하는 원리의 초음파 도플러 유속 측정 관계식이다.Equation 2 is the power spectral density in the ultrasonic irradiation region

Flow rate by measuring

Ultrasonic Doppler Flow Rate Measurement

를 산출하게 되는 원리이다.In this case, the ultrasonic Doppler signal from the sensor is analyzed by the frequency spectrum to calculate the power spectrum and the fluid flow velocity

It is a principle that yields.

However, the processes of calculating the ultrasonic Doppler signal in the frequency spectrum and calculating the power spectrum process the signal for the fluid flow rate using only the conventional analog circuit method as shown in FIG. 3 or a digital logic circuit such as an individual digital circuit or a gate array. The method can be measured only within a limited range, and the error factor is very large. Even if the signal processing speed is processed using a conventional microprocessor, the signal processing speed is slow, so all signals from the flow sensor can be detected. It is pointed out that it is impossible to process in real time and that the flow rate is calculated only by the arithmetic mean within a limited range.

A feature of the present invention to solve this problem is to process the signal using a DSP (Digital Signal Processor), which is the most efficient method for processing the ultrasonic Doppler signal, but the ultrasonic signal is reflected and scattered from a number of particles The average flow velocity of sewage flow is calculated by processing FFT (Fast Fourier Transform), Time Gating or Range Gating, etc. The method is to analyze the received reflected waves with a certain time difference to measure the flow velocity distributions according to the distance from the ultrasonically irradiated area to the sensor. The range dividing method receives the water level signal from the pressure gauge. The average flow velocity of the whole fluid in the sewage pipe is measured by optimizing the output ultrasonic intensity according to the Calculate the flow rate, and calculate the flow fluid area in the conventional obesity tube flow measurement method and calculate the flow value through calculation with the flow velocity. The internal diameter of the sewage pipe is set in advance and built in or separately from the flow measurement sensor in order to solve the closed end where the error occurs above the expected level due to the segmentation of the table data that calculates or indirectly calculates the area through the linear linearizer. In addition to measuring the water level through the water level signal of the sewage flow fluid from the installed pressure level sensor, the sewage flow area is calculated directly from the water level signal in real time. In calculating the flow rate.

In order to solve the above-mentioned problems, the present invention uses a digital algorithm that processes the signal processing and arithmetic operations at 150MIPS using D.P. The purpose of this is to calculate the flow rate value by spectral analysis and statistical calculation of ultrasonic frequency according to the sewage flow state in the sewage pipe, and to measure the sewage flow rate of the sewage pipe.

Another object of the present invention has a measuring range of ± 0.025 ~ ± 4.0 [m / s] for measuring the flow rate of the sewage in the sewage pipe and can maintain the flow rate of 2% FS in the flow rate range of 1m / s or more In particular, the flow rate such as the reverse flow is measured in the same performance range as the forward flow rate to be very useful for observing the flow state of the sewage in the sewage pipe.

Another object of the present invention is to require a function such as not only to transmit digital data to a remote place in real time even during actual measurement of a sewage pipe flow meter, but also to collect and store measured data for a predetermined period even when the communication line is disconnected. According to the present invention, even in the above complicated situation, while measuring the flow rate at the same time to store the measured data for a certain period or more to transmit the data digitally to the remote place, and through the main processing unit equipped with embedded Linux to easily check the status of the flow meter We want to implement some add-ons.

In order to realize this, the present invention installs a general USB memory inside the flowmeter, thereby establishing a database of flowmeter measurement data and measurement data and storing the measurement data for a period of more than one year. The reliability of the measurement data and the safety of the flow meter are secured, and the above-mentioned USB memory can be directly removed and used in a personal computer (PC) to analyze the sewage flow rate data in the sewage pipe. And easy-to-use, and through the serial communication port such as Ethernet (Ethernet), even while the flow meter is performing the measurement work, it is possible to download the measurement data stored in the USB memory from a remote location It was possible to check the flow meter.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Figure 5 is a block diagram of the ultrasonic Doppler flow meter for sewage pipe according to the present invention.

First, the flow meter 1 of the present invention includes a flow rate measurement sensor unit 2, a signal amplification and analog circuit unit 3, a DSP signal processor 4, a main processor 5, T.F. TFT LCD display unit 6, Interface unit 7, USB memory unit 8, Sensor automatic cleaning device 9, Sensor automatic cleaning Compressed air generating device 10 for.

In the above bar, the flow measurement sensor unit 2 is installed on the bottom surface of the sewage pipe, etc., and is a detection unit for measuring the flow rate and the water level of the flow sewage, and the flow measurement sensor unit 2 includes sand which may always exist in the sewage pipe. The sensor automatic cleaning device 9 is integrally attached so that deposits such as foreign matters are deposited on the flow rate measuring part 2 so as not to interfere with the measurement of the flow rate or water level, and when used in sewage pipes, In addition to preventing malfunction or burnout of the sensor, the flow rate and water level signals are transmitted to the DSP signal processor 4 through the signal amplification and analog circuit unit 3 through a dedicated signal cable.

The DSP signal processor 4 receives the water level signal according to the water level in the sewer pipe from the flow measurement sensor unit 2 to calculate the area in which the fluid flows in real time and to generate the ultrasonic Doppler signal according to the fluid flow rate. The DSP signal processor (4), which operates as a 32-bit DSP, receives the input and calculates the flow rate in real time using an ultra-high-speed digital algorithm. The gain of the ultrasonic waves is adjusted in real time.

Meanwhile, the ultrasonic flow sensor 2a and the ultrasonic wave sensor 2b are separately installed in the flow measuring sensor unit 2 to minimize the flow rate dead zone, and the D.P. (DSP) The signal is directly input to the signal processing section 4, and the DSP signal processing section 4 converts the ultrasonic Doppler signal into a high speed A.D. to use a digital high speed algorithm. FFT computation, signal filtering, and calculation of various real-time flow rate values allow effective and stable measurement of sewage flow in sewage pipes.

The main processor 5 is equipped with a 32-bit ARM embedded processor, 64 Mbytes of Flash ROM and SDRAM, respectively. Connects to the TFT LCD display part 6 using the TFT LCD, and displays and processes it with the Graphic User Interface (GUI), RS-232C / 422/485, etc. Serial port, Ethernet, and Bluetooth communication interfaces make it easy to transfer measured data, while embedded Linux using 2.6.x kernels is measured. In addition to storing raw data including measurement data, measurement date and time, and transmitting them to a remote location, all settings and measurement data of the flowmeter can be transferred to the TFT LCD. The display section 6 allows monitoring and management settings. By using Ethernet, Bluetooth, Serial Port, etc., it is free to transmit measurement data and check and set the internal state of the flowmeter 1.

That is, the flow meter 1 provides the user with convenient access by the TFT LCD display unit 6 described above.

The interface unit 7 transmits measurement data to a serial port, such as RS-232C / 422/485, Ethernet, Bluetooth, and the like, and checks and checks the state of the flow meter 1. In particular, serial port or Ethernet can be used for real-time transmission of measurement data.

And it can output according to flow rate, flow rate and level signal using current output signal of 4 ~ 20 [mA], and pulse output for measuring the accumulated flow rate is to measure the accumulated flow rate outside the flow meter (1). Enable the connection of digital counters, etc.

 The USB memory unit 8 allows a large capacity removable USB memory to be directly connected and used for more than one year in the USB memory. In order to make the measurement data efficient and easy to manage or utilize the measurement data, the database is organized through a file system by year, month and day so that it can be easily used in general user computers (PC).

Finally, the automatic sensor cleaning device (9) is a flow measurement sensor in order to prevent a lot of foreign matters contained in the sewage flowing in the sewage pipe is deposited in the lower portion of the sewage pipe to be an obstacle to measuring the flow rate in the flow measurement sensor unit (2) A device integrated into the unit 2, which deposits compressed air from the compressed air generator 10 for automatic sensor cleaning through the nozzle of the automatic sensor 9 for cleaning, and deposits deposited on the flow rate sensor unit 2. It was configured to automatically clean the flow rate measurement unit (2) by using a principle that is separated from the bottom surface of the sewage pipe and moved by sewage flow.

        In particular, the sensor automatic cleaning device 9 provided in the flow rate measuring sensor section 2 is configured such that the main processing section 5 controls the sensor cleaning cycle value set in advance according to the water level, the flow rate, and the measurement cycle.

As described above, the present invention measures the flow rate and the water level due to the fluid flow in the sewage pipe at the same time to measure the sewage flow rate in the sewage pipe, and the ultrasonic doppler type tube and obesity pipe configured to transmit remotely while storing the measurement data in the flowmeter itself for a long time. Ultrasonic Doppler measures the flow rate of sewage flow fluid by directly processing the measured signal from the flow sensor as a flowmeter using a high-speed digital algorithm in a DSP (Digital Signal Processor) operating at 32bit, 150MHz speed. When analyzing the signal data from the flow measurement sensor using a statistical method, an effective and efficient approach is to remove and remove noise components at scattered and reflected frequencies from suspended particles composed of various foreign bodies of sewage fluid. FFT computation and high speed digital fill By processing the signal data according to the flow rate of sewage flow fluid through the turing operation, the ultrasonic Doppler signal according to the fluid flow rate is analyzed and measured by the power spectral density in the area before the ultrasonic irradiation from the flow rate sensor. It has the effect of greatly improving the accuracy, and it is possible to measure the reverse flow rate in the same direction, and it is more efficient in general user computer (PC) by building and using the database in USB memory. In addition to the flow measurement data management and at the same time the flowmeter can be directly connected to the Internet via Ethernet, through which the measurement data stored in the flowmeter can be downloaded or the flow measurement data can be checked and checked through the Internet. Has achieved the effect Wu large.

Claims (8)

A flow rate sensor unit 2 installed at the bottom of the sewage pipe to measure the flow rate and the water level of the sewage; A signal amplification and analog circuit unit 3 for amplifying the signal sensed by the flow measurement sensor unit 2; The signal amplification and the signal transmitted from the analog circuit unit 3 is input to calculate the area in which the fluid flows in real time, and receives the ultrasonic Doppler signal according to the fluid flow rate to calculate the flow rate value in real time using a digital algorithm, the water level change A DSP signal processor 4 for adjusting the gain of the ultrasonic wave in real time according to the present invention; The data processed by the DSP signal processor 4 receives the raw data measured, the measurement result data and the measurement date and time are stored and transmitted to the remote site, and the flowmeter settings and measurement data A main processor 5 for monitoring; A TFT LCD display unit 6 for displaying and processing the data processed by the main processing unit 5 by a GUI (Graphic user interface); An interface unit 7 connected to the main processor 5 through a serial port and Ethernet Bluetooth to transmit data processed by the main processor 5; A USB memory unit 8 detachably connected to the flowmeter and storing data processed by the main processing unit 5; A sensor automatic cleaning device (9) for removing deposits deposited on the flow rate measuring part (2) by using compressed air; And Ultrasonic Doppler flow meter for sewage pipes, characterized in that it comprises ;; compressed air generator for automatic sensor cleaning for supplying compressed air to the automatic sensor cleaning device (9). The DSP signal processor 4 according to claim 1, wherein the DSP signal processor 4 uses a digital signal processor (DSP) operated at a 32-bit 150 MHz using a high-speed digital algorithm. Ultrasonic Doppler flow meter for sewage pipe processing, characterized in that the signal processing. 2. The FFT analysis of the ultrasonic Doppler signal from the flow rate sensor part 2 of the flowmeter 1 using a DSP (Digital Signal Processor). Ultrasonic Doppler flowmeter for sewage pipes, characterized in that by measuring the power spectral density in the ultrasonic irradiation region through the same degree of forward and reverse bidirectional flow rate. The ultrasonic doppler flow meter according to claim 1, characterized in that a database is constructed in a USB memory unit to store and manage measurement data. The ultrasonic doppler flow meter according to claim 1, characterized in that a sewage pipe sensor automatic cleaning device (9) is attached to the flow measurement sensor unit (2). The system of claim 1, wherein the main processor 5 implements a soft realtime system as an embedded Linux system equipped with a Linux kernel, and a digital signal processor (DSP) signal processor (4). Ultrasonic Doppler flow meter for sewer pipes, which is implemented by a dual operating system (OS) system by implementing a hard real time system. 2. The interface unit 7 according to claim 1, wherein the interface unit 7, which is data communication, is equipped with a complex communication interface system such as Ethernet, Bluetooth, RS-232C / 422/485, etc. Ultrasonic Doppler flow meter for sewage pipes, characterized in that it enables Internet connection and short-range wireless connection via Bluetooth. 2. The LCD of claim 1, wherein a 6.4 ″ TFT LCD is used as the TFT LCD display 6 and a touch screen is used. And an ultrasonic Doppler flow meter for implementing sewage pipes, which implements a graphical user interface (GUI) system.

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