| 摘要 |
A tank lid having flexible polymeric material forming an annular torus surrounding a discoid portion, pins retaining the torus seated on the upper edge of the tank. A proximity sensor which senses bulging of the discoid portion, the proximity sensor actuating a valve which will stop entry of gas such as nitrogen upon the disclosed portion bulging upwardly but allow entry of the gas when it deflects downwardly.
|
