Single-discharge valve device
    For low vacuum (or in low-pressure) pneumatic conveying systems, can make use of discharge valve-to-row dumping material (or feed). This discharge is the working principle: the valve in the upper part of a certain height of the column is expected to ensure that the necessary air tightness, as the valve up and down the pressure difference and weight of the block, the valve being sucked in the framework of the On. Separated from the separator material accumulated in the upper part of the valve, when the column is expected to reach a certain height, materials and valves for gravity axis of moment equilibrium, that is, when the following conditions are met, the valve began to rotate around the axis, with the framework From the upper material from the formation of the gap in unloading.  
    This no-discharge drive to create a simple, easy to adjust, less broken material. But the disadvantage is that: the height of large, poor air tightness.

Double-discharge valve
     Double-discharge valve, which of the two-hopper up and down, up and down through the valve, according to a certain turn of the opening and closing cycles combined for discharge. The gate valve cam style electric, pneumatic piston, cam with open, closed by weight, and material on self-open, closed by a number of weight and so on. Unloading equipment for the upper-negative, and positive pressure for lower, because of air emission discharge and the direction of unloading the opposite direction, in order to eliminate the discharge Shangcuan airflow obstruction, waiting for the discharge of the discharge-pressure pipe were to be installed In pre-open the valve to open all the Tube pressure valve, the valve so that the hopper up and down (or container), the pressure balance. 
     This dual-discharge valve's air tightness than single-valve, but a high degree of a larger size, more complex structure, automatic control more difficult and therefore a higher cost. General schedule for unloading high-temperature materials and grinding of materials.

Butterfly-double combination Discharge
    Using up and down the installation of butterfly valves for pneumatic double combination, the valve between the upper and lower left some space (about 0.5-1m or so), work to open the upper part of the valve plate, to be in the pipeline there is a certain amount of material, to close at Valves, to open at the same time carried out under the discharge valve, the valve to open up and down through the combination of time and confined to meet discharge requirements.