For numerous products packed under pressure, the content and the propellant must be kept separate. To meet this requirement, dual compartment packaging was developed. Coster’s BOV system consists of an aluminum or tinplate can closed by a valve on which a flexible multilayer film bag, containing the product to be dispensed, is affixed or welded. The propellant, liquid gas or compressed gas (nitrogen, air), is contained inside the can outside the bag and squeezes the bag to expel the product through the valve.
All Coster BOVs guarantee a high drop resistance even with repeated drops. Valves are available in many different versions offering varying flow rates suitable for a broad range of applications. A variety of actuators and caps are available for sprays, gels and other products.
All materials, including bag and seal, comply with FDA regulations regarding food contact. Coster maintains a DMF for its BOVs for pharmaceutical applications.
The system can be used with standard cans, so the same machines with minor adjustments can be used to fill cans equipped with either standard or BOV valves.
In the NKLCU, KTCS, KTCSU, 20 BOV (press-down) and NRTLC, NRTLCU (tilt action) versions the bag is fixed with a plug. The exclusive, patented valve-bag coupling and the valve bodyin acetalic resin give to these versions high tightness and total impermeability, allowing the use of liquefied propellant. Liquefied propellant, compared to compressed gas, has asignificant advantage: the delivery rate is constant independently from the quantity of product that has already been dispensed.
These versions can also be pressurized both with compressed gas. Liquefied propellants are filled through the valve. Compressed gasses are filled under-cup. The product is filled into the bag through the valve’s stem. High impermeabilitymakes the system fully suitable for pharmaceutical andcosmetic applications.
These versions can be used with aluminum and tin platecans with max Ø 53 mm and max filling volume 300 ml.

In the KWBU (male) and KWBFU (female) versions the film is welded on the polyethylene or polypropylene valve body. These versions can be used only with compressed gasses, with aluminum and tin plate cans with max Ø 66 mm and max filling volume 500 ml. Also available are special versions suitable for an irradiation treatment for sterilization.