Micro-dispensing valves have micro-liter or nano-liter dispensing capabilities and dispensing frequencies in the cycles/sec (Hz) range. They often have interfaces for integration into circuit boards and are frequently used in inkjet printers. Micro-dispensing valves are miniature solenoid valves that can dispense small amounts of liquids in a repeatable pattern, making them useful in all kinds of high-speed precision dispensing applications. Other dispensing valves are used in larger scale applications, such as food and beverage packaging. A beverage dispensing valve may be part of a larger system of mixing valves that combines syrups, carbonated water, and other liquids to make soft drinks or other consumer beverage products.
Micro-dispensing valves can handle a variety of different fluids with varying viscosities. Micro-dispensing valves are also designed to function under different pressure and speed conditions, and may also be configured for time-based or time-metered dispensing. A micro-dispensing valve may dispense water-based or solvent-based liquids and can operate with response times as fast as 0.25 milliseconds between dispensing. Micro-dispensing control valves can be used on printed circuit boards (PCB) at high speeds up to 1200 Hz. Micro-dispensing valves can also be used to dispense air, biological reagents for medical applications, and other fluids including alcohols. Micro dispensing valves are designed as closed coil devices to minimize corrosion from spraying or splashing of fluids.
Micro-dispensing valves may be solenoid-actuated or may also include piezoelectric crystals that can translate mechanical motion or pressure into voltage. This technique also works in the reverse: by applying a voltage to a piezoelectric crystal-actuated valve, the electric charge causes the crystal to vibrate or oscillate. Miniature piezoelectric valves are frequently used in inkjet printers. In a miniature piezoelectric valve, a piezoelectric crystal is used in the ink nozzle. An electric charge causes the crystal in the piezoelectric valve to expand and the valve dispenses the ink on the paper.