| 摘要 |
A safety valve for venting stationary fuel tanks during loading or unloading is described. The safety valve opens when the pressure inside the storage tank exceeds a certain maximum level during loading of the tank or falls below a certain minimum level during unloading of the tank. The valve basically contains a rupture disc (4) with an element (3) that is ejected from disc (4) in case of to high or too low pressure in the tank. The disc (4) contains magnetic elements (10). Under normal operating conditions the magnetic elements (10) keep disc (4) in contact with bottom disc (6) containing a steel ring (11). If the pressure in the tank rises, the force acting on rupture disc (4) overcomes the magnetic force and disc (4) slides in an upward direction inside cover (1) until it is stopped by a protusion inside cover (1). If the pressure inside the tank increases further and finally exceeds a certain maximum pressure level, element (3) is ejected from disc (4) and the tank is vented. In case the pressure level in the tank falls below a certain minimum pressure level during unloading of the tank, element (3) is ejected from disc (4) as well and atmospheric pressure is restored in the tank. |
