This is the most economical type of bottle filler for a limited range of applications. This filler is best suited for liquids with very thin viscosities that do not change with ambient temperature or with batch variation. This machine is also suited for applications where recirculation of the liquid in the fluid path is not desirable. This is especially true for corrosive chemical filling like acids and bleach. Other examples of products this machine is well suited to include water, solvents, alcohol, specialty chemicals, paint and inks. Although this type of filler is used predominantly on products that do not foam, foam may be limited and controlled by subsurface/bottom-up-fill capability.
The machine works by a simple principle; the amount of liquid flowing through a fluid path will always be the same for a fixed amount of time. It functions as follows: the product bulk supply is pumped into a holding tank above a set of pneumatically operated valves. Each valve is independently timed by the filler's master computer so that precise amounts of liquid will flow by gravity into the container. Independent timing of each filling valve/nozzle corrects for minor variations in flow rates so that each container is filled accurately.
The disadvantage of this type of technology is that the dynamics of the fluid path and nozzle actuation characteristics continuously change over time. This requires the operator to make adjustments to the machine's stored parameters more frequently than other technologies. Notwithstanding this drawback and the limitation of the range of products that can run on this filler, it offers excellent value for its performance.