CNG gas cylinders

CNG cylinders are high-pressure containers used to store compressed natural gas, which are explosive pressure vessels containing flammable and explosive gases. The storage pressure for automotive cylinders is 20MPa.

CNG gas cylinders are divided into four categories

The first category is seamless alloy steel cylinders (CNG-1).

The second category is composite gas cylinders with an alloy steel liner plus a cylinder body reinforced by glass fibre ring winding (CNG-2).

The third category is composite gas cylinders with aluminium liner plus carbon fibre fully wound and glass fibre ring wound reinforcement (CNG-3).

The fourth category is the composite gas cylinder with plastic liner plus carbon fibre full winding and glass fibre ring winding reinforcement (CNG-4).

Each of these cylinders has its own advantages and disadvantages and can be used depending on the model.

The main cylinders used worldwide are steel cylinders, generally made from high quality chromium-molybdenum steel, and the ISO 11439 and ECE R110 standards can meet the requirements of most countries.

A complete automotive CNG cylinder has a cap, a valve and a safety relief device. The cap protects the valve and the safety relief device on the valve should be of the rupture disc-fusible plug combination type.

1, the use and installation of compressed natural gas cylinders for automobiles shall comply with the provisions of the relevant standards, and shall be issued by each region unified with CNG car conversion qualification of the formal conversion plant for conversion and repair, including the installation and removal of gas cylinders. It is strictly forbidden for unqualified units to carry out conversion, repair, disassembly and inspection of gas cylinders, etc., and no digging and welding repair of gas cylinders shall be carried out. The original manufacturing markings and nameplates of gas cylinders shall be complete, the content of which shall be complete and the steel seal shall be clear; the appearance of gas cylinders shall be inspected by the naked eye without permanent deformation and the valves shall be intact.

2. Gas cylinders and their accessories should be inspected for safety before and after filling; the filled gas must be treated with dehydration, desulphurization and de-light oil... The working pressure of the cylinder is the limited filling pressure at the reference temperature (20℃). The filling pressure of the cylinder should be adjusted according to the actual temperature at the time of filling, and its temperature compensation value should be according to the regulations of the filling station. New gas cylinders should be evacuated before the first filling.

3, gas cylinders in the process of use, found that the amount of gas filling and the usual exercise of the number of kilometres does not match, or exercise after a period of time, the pressure in the cylinder significantly decreased, to raise vigilance, timely check whether the leak. If there is serious corrosion or damage or if there is doubt about its safety, it should be inspected in time.

4. The composite layer of gas cylinders should not be scratched, bumped or corroded by acid. Isolated rubber pads should be used between the cylinder and the fastening belt and mounting bracket and should be fastened well. Do not place hard objects in the trunk to avoid bruising or knocking the cylinder. Do not press and place heavy objects on the gas system pipes.

5. Prohibit contact with grease, chemicals, hardware and other substances; scratching, bumping, corrosion and extrusion are strictly prohibited; gas cylinders must not be near heat sources or exposed to sunlight; the distance from open flames should generally be no less than 10 metres; gas cylinders must not be hit.

6、The back box where the gas cylinder is located should use as little or no electrical components as possible, if it must be used, it should also have explosion-proof performance and be installed as far away from the gas cylinder as possible.

7、 The interface between the gas cylinder and the filling valve or pressure reducer which is prone to leakage should be checked frequently.

8、 When the gas cylinder valve is frozen, it is strictly forbidden to bake it with fire. It is strictly forbidden to heat the gas cylinder with a heat source exceeding 40℃; it is strictly forbidden to conduct electric welding arc on the gas cylinder.

9、 Isolated rubber pads should be used between the cylinder and the fastening belt and the mounting bracket and should be well fastened; worn and deformed rubber pads should be replaced in time.

10. The following unexpected situations should be inspected at any time.

(1) Accidents and cylinders or vehicles on fire, subjected to shock, overheating or confirmed to have been damaged in some other way.

(2) Damaged by chemicals.

(3) overpressure of gas cylinders or damage by cargo or vehicles

(4) Other abnormalities, natural odours (confirmed to be non-pipe leaks), unexplained drops in gas pressure, unusual noises, signs of loose installation.

(5) Gas cylinders in stock or out of service for more than one inspection cycle should be inspected before they are put into service.

(6) Other abnormal conditions occur.

(11) When a gas cylinder is found to be out of order during use and there is a malfunction of safety accessories: bottle valve, fusible alloy plug, leaky bottle valve switch failure, etc., the car should first be moved to a safe place, set up a good cordon and sent to a gas cylinder inspection unit or a gas car repair shop after the release of compressed natural gas. It is strictly forbidden to repair and replace accessories on your own.