Vacuum packaging machines protects foodstuffs against atmospheric conditions. These machines are ideal for supermarkets, butchers, delicatessen and many more food services. Many types of food such as meat, poultry, cheese, and coffee are vacuum packed to extend shelf life and storage time. Foods that contain small amounts of oxygen spoil more slowly. When food is packaged, an inert gas enters the packaging to change the conditions of the atmosphere, to guarantee better protection of the product. At the end of the process, the plastic bag is closed.
Solenoid Valve Application
Foods in plastic bags are blocked under the transparent bowl. The lid is lowered and the vacuum cycle begins at the push of a button. The air inside the chamber is sucked in by the pump as indicated by the arrows (fig. 1); a vacuum is generated and the plastic bag sticks to the product; one edge of the bag is then sealed. When this process is finished, atmospheric pressure in its chamber is restored (Figure 2) and the lid is opened. In this application for the vacuum cycle; two vacuum solenoid valves are used. The first ensures that the pump sucks air from the chamber and when the suction is finished, the vacuum in the room is kept. Second, the package restores atmospheric pressure after closing.
Recommended DURAVIS ESV 300 Series Vacuum Solenoid Valves:
The critical parameter of this application is not pressure, but cycle time (greater efficiency). Therefore priority will be given to the nominal diameter of the valve as large as possible. The choice (except for direct-acting valves for small machines) goes to pilot operated valves with lift support. (Assisted-Lift)
In DURAVIS ESV 300 series, the core is connected directly to the diaphragm by means of a spring. For this reason, it works with a minimum differential pressure requirement. They have a larger orifice diameter than similar valves produced by our competitors and therefore show higher performance.
Warning: In vacuum applications, the direction of the valve should generally be positioned according to the suction of the vacuum pump.