Constant quantity vapour filling valve

A constant inlet piston valve consists of an upper joint 1, a differential inductor 2, a spring-back body 3, a regulating valve 4, a central body 5, an external tube 6, a pressing cap 7, a regulating ring 8, and a sealing body 9. The differential inductor 2 can do action reciprocally with the spring-back body 3 and dominates the valve mouth of the regulating valve 4 to do the synchronization action at the same time. So the influence of pressure exchange is reflected on the restricting area of the valve mouth to lead the amount of infusing steam flow of the constant inlet piston valve to keep stable during the whole course of infusing gas; the process can guarantee the actual amount of infusing gas of each inlet unit to lead an impregnating layer to attain effective infusion and lead to the improvement of infusing effect and crude oil harvesting. The inlet piston valve is simple in structure, reasonable in design and suitable for widespread utilization.