廣州森納士儀器有限公司

I. Introduction:

DG series explosion-proof pressure transmitters are widely used for CNG dispensers and gas filling stations. Their high precision, high stability elastic sensitive membrane, sophisticated encapsulation technology and mature assembly technology ensure the accurate measurement and display of gas filling pressure, and keep gas tank pressure within specified range. With application and experience for over a decade, SENEX has gained considerable recognition in the industry, and won favorable comments from users.

II. Major technical specifications:

Measuring medium  Various liquid, gas or steam that is compatible with 316 stainless steel
Measuring range    Gauge pressure of 0~0.01MPa to 0~250MPa, absolute pressure of 0~0.1MPa to 0~250MPa, and vacuum of 0~-0.1MPa   
Output signal      4~20mADC (two-wire system) 0~10VDC, 0~5VDC, 1~5VDC (three-wire system)
Supply voltage        9~36VDC (two-wire system), 24±5VDC (three-wire system)
Accuracy           Class 1.0, class 0.5, class 0.25 (composite errors including nonlinear, repeatability and lag errors)
Installation method   Thread installation
Pressure connection  M20×1.5, M12×l, Gl/4, Gl/2 male thread, etc.
Electrical connection  Standard type: four-core shielded cable (IP65 protection level), circular connector, DIN connector
Explosion-proof mark:  Flameproof dI, dIICT6 intrinsically safe iaI, iaIICT4; iaIIBT4

III. Typical applications

(1) Photo and internal structure diagram of CNG dispenser (as shown below):

Photo and internal structure diagram of CNG dispenser (as shown below):      Internal structure diagram of the dispenser

(2) Main functions:

1.  Equipped with monitoring system to monitor the temperature, pressure and flow of the gas filling process, and control the gas filling speed; 
2.  Equipped with safety interlocking system to automatically cut off gas source upon loss of pressure, overpressure and overflow of gas filling hose; 
3.  Use imported mass flowmeter featuring automatic pressure and temperature compensation; 
4.  Power failure protection, display recovery upon power failure;
5.  Mature data storage, management and query functions; 
6.  Statistics of dispensing;
7.  Preset with fixed quantity/amount dispensing;
8.  Directly display pressure when dispensing; 
9.  Automatic fault monitoring, automatic display of fault codes;
10. IC card dispenser has IC card automatic settlement function (non-IC card dispenser is reserved with IC card system interface); 
11. Reserved with tax control interface; and
12. Reserved with communication interface.

(3) Process flowchart of gas filling station (as shown below):

The gas comes from the natural gas pipeline, enters the purification and desulfurization system through the metering and regulation device, and enters the compressor unit, where it is compressed to 25MPa and treated by the high pressure dehydration plant. Now the compressed natural gas can be directly filled into the gas cylinder of the car, or filled into the gas cylinder of the CNG trailer to transport to the sub-station, which is called slow gas filling. Also, the compressed natural gas can be stored in the gas storage cylinder group, and filled into the car through the sequence control board, which is called rapid gas filling.