What is the working principle of the emergency break - away valve for loading arms?
The emergency break - away valve for loading arms, also known as a breakaway coupling, is a crucial safety device widely used in industries such as oil and gas, chemical engineering, and liquefied natural gas (LNG). Its main function is to automatically cut off the fluid flow when the loading arm is accidentally broken or subjected to excessive pulling force, thereby preventing leakage accidents and safeguarding the safety of personnel and equipment.
I. Working Process
In normal operation, after the loading arm is docked with the tank truck, first manually remove the safety bolts (simply unscrew the dovetail nuts). Then, the valves can be opened for loading and unloading operations. After the loading and unloading operations are completed, the safety bolts should be installed first, and then the separation operation between the loading arm and the tank truck should be carried out to return the loading arm to its original position. In case of an emergency, if the tank truck moves accidentally, the emergency break - away valve of the loading arm will automatically disconnect, preventing the loading and unloading pipes from being broken and causing leakage due to the unintended movement of the loading and unloading tank truck.
II. Safety Performance
The emergency break - away valve of the loading arm has a highly reliable cutting action and is very suitable for cutting off, regulating, and throttling the medium. It enables the equipment to automatically and quickly disengage in an emergency situation while avoiding accidental disengagement during normal operations, which could affect the normal loading and unloading operations. In addition, the break - away mechanism should not only ensure that the equipment can automatically and quickly disengage during emergency disconnection but also provide a buffer period before disengagement to avoid disconnection during normal operations.
III. Sealing Performance
After disengagement, the end of the emergency break - away valve of the loading arm connected to the hose will inevitably fall to the ground and be dragged away by the tank truck. To prevent sparks from intense collisions, stainless steel (usually 304) or brass is selected as the material. However, for the emergency disconnection device of the loading arm type, after disengagement, neither end will fall to the ground, and carbon steel can be selected. But considering the need for rust prevention, all metal components are surface - plated with hard chromium (or electroless nickel - plated). This ensures that the two separated parts can be effectively sealed after emergency disconnection.
IV. Restoration Process
During the restoration process after disengagement, the pipelines need to be emptied before restoration work can be carried out. Before restoring the emergency disconnection device, check whether the main seal and the secondary seal are damaged (burned out). If there is damage, remove the main seal seat and replace the main seal; otherwise, simply replace the new break - away bolts.
