The LNG vehicle-mounted gas cylinder is fully assembled and can be divided into 7 main parts: inner container, outer shell, insulation layer, support device, liquid filling system, pressurization system and vaporization system, realizing the four major functions of storage, transportation, liquid supply and gas supply.
The LNG vehicle-mounted gas cylinder is composed of an inner liner and an outer shell.
The inner tank is used to store liquid natural gas. It is a closed pressure-bearing cavity welded by a straight cylinder and an EHA-type standard elliptical head. The structural material is stainless steel.
The function of the shell is to provide a closed vacuum chamber for vacuum insulation. The shell is welded by a straight cylinder and a THA standard dish-shaped head. The structural material is stainless steel. Due to the existence of a vacuum, the shell bears external pressure, and the shell and its supporting system can withstand various forces transmitted by the car.
The outer wall of the inner liner and the inner wall of the outer shell constitute a closed vacuum chamber. LNG vehicle-mounted gas cylinders are insulated with high-vacuum multilayer winding. The vacuum cavity is filled with multiple layers of heat-insulating material and reflective aluminum foil, and the heat-insulating material and the aluminum foil are alternately wrapped on the outer wall of the inner tank. Insulating materials, aluminum foil and vacuum form an efficient insulation system.
Two safety valves are used for overpressure protection of LNG vehicle-mounted gas cylinders. The first to open is the main safety valve, which is designed to safely release the pressure increase in the inner container caused by normal heat leakage (heat leakage through the insulation and support system). The second is the auxiliary safety valve, which has a higher discharge pressure. It is designed to provide secondary protection for the inner container when the main safety valve fails or is blocked. The two protections are designed to ensure the safe use of lng vehicle gas cylinders.
The shell is equipped with a shell explosion-proof device. In the event of LNG leakage of the liner, the shell will bear internal pressure. The purpose of the shell explosion-proof device is to limit the internal pressure of the shell to a set safe level in case of LNG leakage of the liner. In order to simplify the structure, the shell explosion-proof device and the vacuum plug are combined to design a component, through which the vacuum pumping and vacuum plugging can be realized. As the shell explosion-proof device, when the internal pressure of the shell is exceeded, the plug on the component will open the pressure relief.
The support system is two saddle-shaped bearings, one of which is fixed longitudinally (fixed end), and the mounting hole on the base plate is a round hole. The other is longitudinal sliding (sliding end), the installation hole on the bearing bottom plate is a waist-shaped hole, which is conducive to thermal expansion and cold contraction compensation. The pipe system, instrument and valve are fixed at the fixed end and protected by a protection ring.