Cover systems for storage tanks, such as those containing at least some petroleum. Pipe retention systems for retaining pipes to storage tanks, such as pipes that can transmit liquid containing at least some petroleum. Methods of attaching cover systems to tanks.

Cover systems for storage tanks, such as those containing at least some petroleum. Pipe retention systems for retaining pipes to storage tanks, such as pipes that can transmit liquid containing at least some petroleum. Methods of attaching cover systems to tanks.

A scarifying rig may be mounted on the surface of a floating roof to move about the perimeter of the roof. The rig comprises a trolley, one or more support rails fixed on the trolley, and a horizontal arm mounted on the support rails for controlled movement along the support rails. A vertical rail is attached substantially to the end of the horizontal arm for reciprocating vertical movement (up and down) about the end of the horizontal arm. A nozzle assembly is mounted to the vertical rail.

A scarifying rig may be mounted on the surface of a floating roof to move about the perimeter of the roof. The rig comprises a trolley, one or more support rails fixed on the trolley, and a horizontal arm mounted on the support rails for controlled movement along the support rails. A vertical rail is attached substantially to the end of the horizontal arm for reciprocating vertical movement (up and down) about the end of the horizontal arm. A nozzle assembly is mounted to the vertical rail.

A scarifying rig may be mounted on the surface of a floating roof to move about the perimeter of the roof. The rig comprises a trolley, one or more support rails fixed on the trolley, and a horizontal arm mounted on the support rails for controlled movement along the support rails. A vertical rail is attached substantially to the end of the horizontal arm for reciprocating vertical movement (up and down) about the end of the horizontal arm. A nozzle assembly is mounted to the vertical rail.

A scarifying rig may be mounted on the surface of a floating roof to move about the perimeter of the roof. The rig comprises a trolley, one or more support rails fixed on the trolley, and a horizontal arm mounted on the support rails for controlled movement along the support rails. A vertical rail is attached substantially to the end of the horizontal arm for reciprocating vertical movement (up and down) about the end of the horizontal arm. A nozzle assembly is mounted to the vertical rail.

A vent valve includes an outer frame, a ventilation box movable in the outer frame, a sealing cover, a buoyant box and elongate sliding members. The ventilation box has an interior space. The sealing cover has a cover opening, and closes/opens a surrounding space defined by the ventilation box and the outer frame. The buoyant box is disposed within the interior space. When the buoyant box abuts the sealing cover and closes the cover opening, the cover opening is disconnected from the interior space. When the buoyant box moves away from the sealing cover, the interior space communicates the cover opening. The sliding members slidingly contact the outer frame and ventilation box to guide sliding movements.

A vent valve includes an outer frame, a ventilation box movable in the outer frame, a sealing cover, a buoyant box and elongate sliding members. The ventilation box has an interior space. The sealing cover has a cover opening, and closes/opens a surrounding space defined by the ventilation box and the outer frame. The buoyant box is disposed within the interior space. When the buoyant box abuts the sealing cover and closes the cover opening, the cover opening is disconnected from the interior space. When the buoyant box moves away from the sealing cover, the interior space communicates the cover opening. The sliding members slidingly contact the outer frame and ventilation box to guide sliding movements.

A sulfur storage tank includes a bottom plate, an outer wall, and a cleanout door. The outer wall surrounds and is coupled to the bottom plate. The cleanout door is installed on the outer wall. The cleanout door includes an edge and a drain nozzle. The edge abuts the bottom plate. The drain nozzle is installed on the cleanout door. The drain nozzle defines a centerline offset from the edge. The drain nozzle is configured to gravity drain fluid from the sulfur storage tank.

A sulfur storage tank includes a bottom plate, an outer wall, and a cleanout door. The outer wall surrounds and is coupled to the bottom plate. The cleanout door is installed on the outer wall. The cleanout door includes an edge and a drain nozzle. The edge abuts the bottom plate. The drain nozzle is installed on the cleanout door. The drain nozzle defines a centerline offset from the edge. The drain nozzle is configured to gravity drain fluid from the sulfur storage tank.