A Filling Machine for the Non Flammable Chemical Industry – Foam control – Economy – Safety
Agricultural chemicals, fertilizers, cleaning chemicals and general industrial chemicals comprise what we refer to as the Non Flammable Chemical Industry (NFCI). These products all share several economic and product handling characteristics. They are usually low value/low margin products and are often sold in bulk sizes. Many of these products are also very foamy and some are also inherently hazardous to the personnel that are packaging them.
All the considerations above will dictate what type of filling machine is the most practical to use for a chemical product or a range of chemical products. Sometimes the choices of these machines are mutually exclusive to each other and that a compromise needs to be made.
In the case of chemicals that are highly foamy but not inherently dangerous to personnel, e.g. cleaning and sanitation chemicals, an Overflow Filling Machine may be the best choice. In the case of chemicals where the major consideration is safety to personnel, e.g. strong acids or toxicity, a time gravity filler may be the best choice. In the case where bulk filling in very large containers is the primary format, a net weigh filling machine may be the best choice. As mentioned above, products in this industry can be both foamy and hazardous and a value judgment must be made. Sometimes it is necessary to compromise performance in the interest of safety. These decisions can be tricky and are best made with the help our applications engineers with years of expert experience.
Overflow Filling Machines for Chemical Products
Chemical products that both foam and are filled into bottles are best suited for filling in an overflow filling machine. The reason for this is that the overflow filling machine is a “closed loop” system that captures the product and the foam during the filling process. Generally speaking, the overflow filling machine is ideally suited for filling products that are foamy into containers with fairly small openings like quart and gallon containers. This filling technology is also the least expensive and easiest to operate for the user.
It should be noted that pressurization of the product and containers takes place on this type of filling machine. Some products may be unsuitable for this pressurization particularly in the case where a faulty setup could cause pressurized hazardous chemicals to spray personnel or cause premature aging of the machine due to constant wetted exposure. This this case, a time gravity filler would be better suited even though there is a small compromise in the best foam handling and a little slower throughput.
As noted above, these NFCI chemicals are also filled into bulk containers e.g. five gallon pails and even larger totes that have large openings and a large airspace to fill; these containers are usually not suitable for filling on overflow filling machines because in the first case, the container cannot practically be sealed to close the loop of the filling fluid path, and in the second case, the amount of foam creation due to the size of airspace would overwhelm the system’s ability to control it. In both these circumstances, a time gravity system or net weigh system is better suited to the task. The choice here between the time gravity and net weigh filling machines would be determined on how the product is sold i.e. by volume or net weight.
It is fairly obvious as to what the criteria would be for choosing the Net Weigh Filling Machine and so we will not pursue it further here.
Time Gravity Filling Machines for Chemical Products
The Time Gravity Filling Machine is often used for filling free flowing, non foaming, non flammable chemicals because of lower relative capital cost and flexibility of container size and geometry. These machines can be used to efficiently fill both containers with smaller openings as well as large bulk containers with large openings. However, if the product is foamy, the time gravity filling machine may not be as efficient as the overflow filling machine for filling containers especially with small openings. Although time gravity filling machines can be configured with subsurface and “bottom up fill” filling nozzles to control foam in smaller containers, this configuration does reduce throughput. On large containers filling either foamy or non foamy chemical products, the time gravity filling machine with subsurface filling capability is a very practical machine to use since the overall throughput requirement on bulk containers is usually low. Time Gravity Filling Machines are also preferred where it is not practical to pressurize or recirculate dangerous chemical products like corrosives or explosives. For more information about this, see the section of hazardous location and corrosive filling machines.
Time Gravity Filling Machines are less expensive to purchase than other types of filling machines but they have higher operational and maintenance costs. Because each filling station has an independently programmed filling valve and fluid path, there is a lot of initial setup time required to configure the machine for each application. Moreover, because of mechanical wear of the valves and hysterisis of fluid paths on this machine, the setup parameters are always being adjusted to keep the machine filling accurately. It must also be noted that any chemicals whose bulk density changes with ambient temperature or batch variations will not perform accurately over time on this type of filling machine. There is also more demand on the operators to keep this machine tuned properly and therefore more risk of costly and inaccurate fills over the period of ownership.