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This standard is prepared with a view to implementing the Environmental Protection Law of the People's Republic of China and the Law of the People's Republic of China on Prevention and Control of Water Pollution, protecting ecological environment, guaranteeing human health and standardizing the technical performance for ultrasonic open channel sewage flowmeter.
This standard specifies the technical specifications, performance indexes and test procedures for ultrasonic open channel sewage flowmeter.
This standard was issued in 1996 for the first time, and the original drafting organizations are Chongqing Huazheng Hydrologic Instrument Co., LTD and other two units. This standard was firstly revised in 2007, and this edition is the second revision.
The following main content has been revised with respect to HJ/T 15-2007:
——The standard name has been revised as Technical specifications and test procedures for ultrasonic open channel sewage flowmeter;
——The requirement of automatic identification of water flow regime in the original standard has been deleted;
——The requirement of trouble-free running time in the original standard has been deleted;
——The test procedures for error of liquid level and flow rate error have been modified;
——The requirements of stage accuracy and flow rate accuracy have been added;
——The requirements of comparison errors of stage and flow rate have been added;
——The interval drift requirements have been added;
——The requirements of minimum maintenance cycle have been added;
——The specific testing methods for each index have been added;
——The distinction between primary instrument and secondary instrument has been defined.
From the implementation date of this standard, HJ/T 15-2007 Technical requirement for environmental protection product — Supersonic flowmeters of wastewater shall be abolished.
This standard is formulated under the organization of the Department of Ecological Environment Monitoring and the Department of Laws, Regulations and Standards under the Ministry of Ecology and Environment of the People's Republic of China.
This standard was approved by the Ministry of Ecology and Environment on December 24, 2019.
This standard has been implemented since March 24, 2020.
The Ministry of Ecology and Environment is responsible for the explanation of this standard.
Technical specifications and test procedures for ultrasonic open channel sewage flowmeter
1 Application scope
This standard specifies the technical specifications, performance indexes and test procedures for ultrasonic open channel sewage flowmeter.
This standard is applicable to the production design, application selection and performance test of ultrasonic open channel sewage flowmeter.
This standard is applicable to the ultrasonic open channel sewage flowmeter (hereinafter referred to as "the flowmeter") for flow rate measurement using weirs and flumes for flow measurement complying with the requirements in JJG 711.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of this standard. For undated references, the valid edition applies.
GB 3836.1 Explosive atmospheres — Part 1: Equipment — General requirements
GB/T 13306 Plates
GB/T 17214.1 Industrial-process measurement and control equipment — Operating conditions — Part 1: Climatic conditions
JJG 711 Verification Regulation of Weirs and Flumes for Flow Measurement
3 Terms and definitions
For the purpose of this standard, the following terms and definitions apply.
3.1
ultrasonic open channel sewage flowmeter
instrument that measures the liquid level at the designated position of the weirs and flumes in open channel (excluding the weirs and flumes) by ultrasonic principle and calculates the flow rate according to the standard equation
3.2
weirs and flumes for flow measurement
device for flowmeter measurement, which consists of upstream and downstream proximal sections, weir bodies and stage observation facilities
3.3
flow rate
liquid volume passing through a cross-section of flow in an open channel per unit of time
3.4
stage
elevation value obtained calculated from the elevation of the measuring reference point (or zero point) plus the distance of a certain liquid level.
3.5
error of liquid level
deviation between the liquid level measured by flowmeter and the measured value of a standard ruler
3.6
flow rate error
deviation between the flow rate measured by flowmeter and the theoretical flow rate
3.7
voltage adaptability
deviation between the measured value and the reference value of the liquid level measured by the instrument at the same height under different voltages
4 Technical requirements
4.1 Basic composition of flowmeter
A flowmeter generally consists of a primary instrument and a secondary instrument, as shown in Figure 1:
Figure 1 Schematic diagram of flowmeter composition
Primary instrument: It transmits and receives ultrasonic waves, converts these signals into sequence electrical signals, and then conveying them to the secondary instrument.
Secondary instrument: It calculates liquid level height through sequence electrical signals and flow rate through a liquid level-flow rate equation, and can display, store and output the measurement results.
4.2 Basic requirements
4.2.1 The identification of the instrument shall comply with the requirements specified in GB/T 13306, and plates shall be fixed in appropriate obvious positions, which shall have the following identification:
a) Name and address of the manufacturer;
b) Name, model and specification of the instrument;
c) End-of-manufacturing number;
d) Date of manufacture;
e) Measurement range;
(f) Operating conditions.
4.2.2 The surface coating of the flowmeter shall be sprayed evenly and has anti-corrosion function without peeling, rusting or scratching. The probe shall be well-sealed. The connecting part shall be fastened reliably. The potentiometer and screws used during adjustment shall be varnished after assembly. The flowmeter shall have anti-corrosion function.
4.2.3 For the application in the environment with explosion-proof requirements, the flowmeter shall meet the explosion-proof technical requirements in GB 3836.1 and be provided with the corresponding explosion-proof qualification certification.
4.2.4 The dielectric strength of the flowmeter shall enable it to withstand continuous voltage test with 50Hz, 1,500V AC RMS for 1 min between the power supply incoming line and the casing, without flashover and breakdown. The insulation resistance between power supply incoming line and casing shall be ≥ 20MΩ.
4.3 Functional requirements
4.3.1 The flowmeter shall have functions of displaying and printing instantaneous stage, instantaneous flow rate, cumulative flow rate and its total measuring time (min or h). Besides, the functions of data memory and storage of the flowmeter are necessary, with the shortest time to keep the existing data in its shutdown state no less than 1 year.
4.3.2 Furthermore, the functions of automatically locking the flow rate calculation parameters and storing data of the flowmeter shall be provided, so as to prevent artificially changing memory data such as the flow rate calculation parameters of the instrument, existing cumulative flow rate and accumulated measuring time.
4.3.3 The modification of the flowmeter key parameters (change of weirs and flumes, calibration stage and calibration time) shall be recorded in the operation log of the instrument, which shall be kept for at least 1 year.
4.3.4 The flowmeter shall have a digital output interface or an analog output interface.
4.3.5 The relevant requirements of the weirs and flumes for flow measurement are implemented according to JJG 711, and the parameters in the flow rate calculation equation of the weirs and flumes may be verified by the standard verification device for open channel flow rate.
Foreword i
1 Application scope
2 Normative references
3 Terms and definitions
4 Technical requirements
5 Requirements for performance indexes
6 Testing of performance indexes
7 Random data