Pneumatic tank truck closure apparatus

In combination:

• a pneumatic tank truck including a tank having a tank interior for holding fluent material under pressurized conditions, said tank having a tank top defining an opening communicating with said tank interior;
• a closure guide leading to said opening attached to said tank on said tank top and extending along at least a portion of said tank top;
• a closure movably mounted relative to said closure guide and movable along said tank top and said closure guide between a first position wherein said closure is over said opening and a second position wherein said closure does not cover said opening and is laterally displaced therefrom, said closure being movable in both a horizontal direction and a vertical direction relative to said tank top and said opening;
• a plurality of rollers operatively associated with said closure for facilitating movement of said closure along said closure guide;
• prime mover means connected to said closure for selectively moving said closure between said first and second positions;
• a seal forming a fluid-tight connection between said closure and said tank top when said closure is in said first position, said seal comprising an inflatable seal disposed between said tank top and said closure when said closure is in said first position, said inflatable seal being selectively alternatively inflated and deflated, said inflatable seal when being inflated and deflated operable to move said closure vertically relative to said tank top and said opening;
• and
• a plurality of restraint members for limiting vertical movement of said closure when said inflatable seal is being inflated.