Function of the small holes on the inner side surface of the vent hole in a floating roof tank’s floating deck

The function of the small holes on the inner side of the vent hole of the floating roof tank’s floating deck is to enable gas exchange and balance between the area above and below the floating deck by connecting with the floating tank. This prevents excessive pressure differences above and below the floating disk, ensuring that it can float properly and maintaining stable gas pressure inside the tank. This is very important for the process management of floating roof tanks, as it ensures the gas sealing and safety inside the tank. .

But in that case, won’t the oil and gas beneath the floating disk mix into the gas phase space above it? Has this been considered as well

Yes, the design of the small holes on the inner side of the vent holes in the floating roof tank’s floating disk takes this issue into account. The function of the small hole is to allow gas to pass through, while preventing liquid from entering. This ensures that the space above the floating disk is primarily a gas phase, preventing liquid from entering and mixing with the gas. By controlling the size and number of small holes, it is possible to balance the gas pressure while reducing the likelihood of liquid entering the floating disk area. This helps maintain the floating capacity of the float and the stability of the related processes. .

Thank you for the advice. I took another close look, and there are also openings on the side of the edge float tank connected to that hole, near the pipe wall. The gas phase space is the area between below the float disk and the space between the float disk beneath the primary seal and the tank wall; it is also connected to the space above the float disk through a breathing valve located above the automatic vent hole. Its function seems to be to maintain stable pressures in the space between the primary seal and the oil surface, as well as in the space below the float disk, while the float disk is floating, thereby preventing gases from breaking through the seal and allowing the float disk to rise properly. Additionally, no measures to prevent liquid from entering were apparent; it’s possible that the height of these openings already takes into account the maximum depth at which the float disk can be submerged, with the openings being positioned above that depth.