Since 2014, the state has required that the dangerous goods tank truck must be equipped with submarine valve components, namely the emergency shut-off valve of the tank truck; although the submarine valve (emergency shut-off valve) is a small part of the tank truck, its role is very important. It can not only slow down the impact on the tank pipe when the vehicle is damaged, but also ensure the sealing of the European standard pipe orifice and prevent oil leakage. The functions and features of the submarine valve (emergency shut-off valve) of the tank truck are as follows: 1. When the tank truck is filled with fuel, the oil and gas recovery valve is opened, and the rising liquid level pushes the oil and gas upward, and returns to the oil tank in the reservoir area through a series of oil and gas recovery systems. 2. When the tanker is unloading, the recovery valve allows the recovered gas to enter the tank. In systems without oil and gas recovery facilities, air is allowed to enter the tank. 3. High sealing ensures the safety of oil tank truck transportation. 4. Reasonable valve body design ensures high efficiency of oil and gas recovery. It ensures the safety of the whole tank truck, avoids the occurrence of dangerous accidents, and greatly ensures the safety. In fact, no one wants the occurrence of dangerous accidents, but they are not accidental. Once it happens, there will be unpredictable losses. The submarine valve of oil tank truck is just a small investment, but it is a safety guarantee. With it, it is equivalent to providing an additional guarantee for your assets and personal safety. It is a warm reminder to the drivers who drive the tank type transport vehicle of liquid dangerous goods. For the safety of you and others, please install the Shanghai bottom valve on your vehicle. In this way, it not only protects your life safety, but also protects others' life safety.