Abstract: Tank valve apparatus providing the usual functions of excessive pressure venting and relief of normal over pressure and negative pressure conditions, and also adopted to instantaneously close the venting system on tanker truck rollover. This is done by an inertia valve which remains closed until the vehicle is righted. The apparatus also includes gravity sensitive flap closures which pivot to a position blocking large fuel surges against the tanker dome cap on vehicle rollover.

Abstract: A tank valve apparatus particularly adapted for effecting rapid discharge of the liquid contents of a tanker truck or the like, the apparatus being characterized by an improved valve opening apparatus actuated by an air cylinder. The cylinder includes a single acting piston requiring a certain cylinder pressure to move the valve to its open position, but requiring a significantly lower pressure to permit its return stroke, whereby rapid closure of the tank valve is facilitated.

Abstract: A safety locking cover assembly for the dome of a tank truck of the type adapted to carry inflammable liquids. A cover is hinged upon a base attachable to the tank dome, and is moved between opened and closed positions by upward pivotal movement of a semicircular handle. The opposite ends of the handle pivot upon a locking bar extending beneath the cover top. The ends of the bar project from opposite sides of the cover and extend into recesses in catches mounted to the base, thereby normally preventing upward movement of the cover relative to the catches. However, the catches are spring biased against the base and are upwardly movable against the spring bias by high internal tank pressures. This provides a relatively large vent opening to vent the tank despite the fact that the handle may be closed. The cover can be manually opened by pivoting the handle through a 180.degree. arc. This moves the locking bar downwardly relative to the catches on the base.