The piston filler is one of the oldest and most reliable types of fillers used in the packaging industry. This bottle filler is best suited for viscous products that are paste, semi paste, or chunky with large particulates. Piston fillers are primarily built to meet food grade standards and commonly fill heavy sauces, salsas, salad dressings, cosmetic creams, heavy shampoo, gels, and conditioners. Thy are also used for viscous chemical preparations like paste cleaners and waxes, adhesives and epoxys, heavy lubricant oils and greases.
The machine works by a simple principle; The piston is drawn back in its cylinder so that the product is sucked into the cylinder. A rotary valve then changes position so that the product is then pushed out of the nozzle instead of back into the hopper. The volume of the product that is sucked into the cylinder is the precise volume that will be dispensed into the container.
The advantage of this type of filing machine is that involves conventional mechanical technology that is easy to understand for most users. It is also the most cost effective, accurate and fastest way to fill fairly thick products. Although more costly than overflow and time gravity systems discussed above, it costs less than the servo pump filler is still the most cost effective bottle filler for thick products.