The solid material always stacks in the bearing chamber of the wear-proof ball valve when the sealing faces of the bearing chamber get too much abrasion for the frequent open and close operation of the valve. Two methods can be used to  avoid the stacking. One is to set blowing holes in the bearing chamber which can  let the gas the pressure of which is higher than the system blow through. The second is to make a design of pressure self-tighten sealing of the bearing chamber, and the self-tighten sealing can get compensation  from the pressure to even the abrasion and to remain good sealing condition for bearing chamber.