Typically, bulk chemical storage tanks are filled in three different ways. One option is via mechanical pump. This technique creates minimal or no additional pressure within the storage tank. A second way of filling a tank is via gravity, like in the case of leachate and condensate flowing out of a landfill basin into a storage tank.
The third and most common method for filling chemical storage tanks is pneumatic filling. With a pneumatic filled system, air pressure is used from the tank truck to offload the chemicals into the bulk chemical storage tank. This technique of pressurized offloading of chemicals from the truck into the storage tank saves filling time.
The challenge with pneumatic filling a bulk storage tank comes from the pressure that builds up in the storage tank at filling time. The delivery truck driver wants to purge all the chemicals from the truck and the fill line to eliminate future spills when refilling the tank, which results in additional pressure on the storage tank.
Specialized Venting System Solutions
Alleviating the pressure in the pneumatic filled storage tank requires more than venting systems designed for day-to-day tank operations. Specially engineered vents and manway covers are needed. The Safe Surge or FS 2650 are required for all pneumatic filled chemical storage tanks. The Safe Surge is a manway cover specifically designed for pneumatic filled tanks. The manway releases at a 6-inch water column as pressure increases, ensuring a proper ACFM during filling operations. The F.S. 2650 manway cover is also designed for pneumatic filled applications and provides tank venting and relief of volume flow rates up to 2650 ACFM.
In addition to appropriate venting systems in pneumatic filled tanks, the proper expansion joints and fittings are important. Flexible expansion joints and hoses expand freely during loading and unloading to accommodate the storage tank’s expansion and contraction from pressure, further protecting the tank against damage.
The proper venting, lids, expansion joints, and hoses ensure safe tank operation, and extend the useful life of pneumatic filled bulk chemical storage tanks.