Piston metering valves are used for handling various mediums with low to high viscosity. The valve body consists of two separate compartments. The advantage of this independent design is that the material does not enter the drive cylinder, affecting the movement of the valve pin. The valve pin is sealed with special sealing material. The amount of adhesive (oil) dispensed can be adjusted by turning the locking bolt on the metering pin. After the lower air source interface injects compressed air, the metering cycle begins. The valve pin rises, injecting material into the metering chamber. When the upper air source interface injects compressed air, it moves the plunger downward, causing the material in the metering chamber to be ejected through the downward movement of the valve pin. At the bottom position, the valve pin closes the oil outlet of the metering chamber, preventing material flow. (Metering range: 0.001 - 3.0 cm)3)。