| 摘要 |
<p>PURPOSE:To make pressures in inner and outer tanks equal and prevent buckling of the inner tank by providing an emergency communication device which is closed in normal operation and opened to communicate atmospheres in the inner and outer tanks by the effort of an atmosphere in the outer tank whose pressure is increased more than that in the inner tank when it is damaged. CONSTITUTION:A roof 11a of an inner tank 11 and a wall 12a of an outer tank 12 are connected by an inverse U-shaped pipe 13. The pipe 13 has at the perpendicular part an emergency opening valve 16 which is kept closed in the normal state. If a low temperature liquid flows out on account of an accident such as a damage of the inner tank 11, a pressure P1 in the inner tank is reduced to a negative pressure because of reduction of liquid level in the inner tank 11 while the other pressure P2 in the outer tank 12 is increased because of rise of liquid level and atomization of a low temperature liquid. The pressures may make a relation of P2>P1. If the differential pressure exceeds a set value, a pressure controller 18 is actuated to open the emergency opening valve 16 so that the atmospheres in the inner and outer tanks may be communicated by the pipe 13 to fall in the relation of P1=P2, thereby preventing the buckling of the inner tank 11.</p> |
