Sonic Nozzle Gas Meter Test Bench GNP Type

Sonic nozzle gas meter test bench GNP type

1、General

• GNP sonic nozzle test facility for gas meters is a new generation automatic test facility with high accuracy, high efficiency and good stability.

• The test facility is composed of sonic nozzle, dynamic image sampling system, test bench, oil-less vacuum pump, controlling gas circuit, single chip system and PC etc. It adopts sonic nozzle as main standard, the nozzles will be selected automatically by PC according to different flow rate. Single chip and high accuracy A/D conversion technology are introduced to automatically measure temperature, pressure and humidity, involved in error calculation and correction. Thus to ensure accuracy of test facility. The whole system can realize full automatic test under PC control and has the function of original data saving, query and printing.

• The test facility can carry out automatic test towardsG1.6, G2.5, G4.0 diaphragm gas meter according to JJG577-2012. The system is with dynamic image sampling, bar code scanning input, auto receive reed switch and pulse signal of gas meter, auto compensation for temperature and pressure, error judgment, data query, storage and printing function.

2、Main Characteristic

• Suitable for test error of G1.6,G2.5,G4.0 domestic diaphragm gas meter under three flow rate Qmax，0.2Qmax and Qmin

• Adopt Venturi sonic nozzle as its standard，automatically select the best nozzle combination by computer according to different flow rate.

• Several gas meters to be tested simultaneously in series connection which greatly improve test efficiency

• Automatically select to test left inlet or right side inlet gas meter by switchover valve

• Reading signal of gas meter can be collected quickly，accurately and reliably via dynamic image processor

• Auto receive reed switch signal and pulse signal output by IC card gas meter

• After test，the system will automatically select the best gas meter gear rate

• Precision sensor，single chip system and high accuracy A/D conversion technology are introduced to automatically measure temperature, pressure, and humidity, involved in real-time error calculation and correction, thus to ensure accuracy of test bench

• The whole system can realize full automatic test under software control. Software interface is characterized by nice appearance and easy operation. Test data and analysis result can link up Excel so as to fulfill test report quickly. It also has data storage，certificate printing，analysis and statistic function.

3、Dynamic Image Processor Characteristic

• High efficiency: Dynamic image processor not only recognize gas meter counter but also count number and count time automatically. Thus，it means shorten run empty time before test gas meter. Especially for 0.2Qmax and Qmin, which greatly enhance efficiency. If we compare with optoelectronic sampling, dynamic image processor can enhance 20%-40% efficiency.

• Long distance test: Dynamic image processor has high pixel, we can enlarge 7cm between camera and gas meter.

• High collection rate: Dynamic image processor has above 99% success rate which collect gas meter signal. It overcomes manual adjustment, difficult to focusing, even collect signal unsteadily after adjustment.

Dynamic Image Processor

4、Ambient Working Condition

• Ambient temperature：20±5℃

• Relative humidity: 30%~80%

• Barometric pressure: 86~106 kPa

• Working media：air

• Power supply：220 VAC

• Compressed air supply：above 0.4MPa

• Facility size：4.8m（L）*0.61m（W）*1.8m（H）

5、System Structure & Working Principle

5.1 System structure（Fig.1）

5.2 Working principle

The equipment adopts Venturi sonic nozzle as its standard. Venturi sonic nozzle is characterized by simple structure, stable performance, high accuracy, easy maintenance, long verification circle( 5 years ), no moving Parts etc.

（Sonic nozzles）

During operation, air flow in the pipe line is realized by pumping. Air enter meter under test through filter, left and right switchover system, then to stagnation container, and then to buffer container via sonic nozzle and control valve, finally into the atmosphere via oil-less vacuum pump. When gas flow through sonic nozzle reaches critical status, mass and flow rate passed though meter under test sonic nozzle will keep unchanged.

So flow though sonic nozzle within time is certain. Meanwhile, the system will receive gas meter sampling signal，temperature sensor signal， pressure sensor signal， humidity sensor signal，get error of gas meter after automatic correction towards those temperature，pressure and humidity influence factor.

6、Main Technical Specification

• System uncertainty：±0.5%

• Suitable to test G1.6，G2.5，G4.0 diaphragm gas meter

• Meter to be tested：6, 8, 12 pcs

7、Installation & Commissioning

• Installation procedure

• Connect test bench and computer

• Connect system power and air source

• Turn on computer, install database and special test software

8、Commissioning Procedure

• Check if all parameter setting is correct

• Check if communication between computer and test bench is normal

9、Software Installation

• System requirement

• Intel Pentium III 866 MHz CPU

• Windows XP or Windows7 system

• 2GB Free disk space

• 4X SPEED CD-ROM

• 2 USB interface

• RS-232 serial com por

10、Facility Picture

Sonic nozzle test facility for gas meter（12 positions）

11、Configuration List