Third as a result of the plunger pump shell level sets of the vertical plane with one axis deviation is too large pressed the plunger after the deformation caused by stagnation seca column.

• 三是由于泵壳上柱塞套台阶平面与其中轴线垂直度偏差过大，压紧后柱塞变形造成柱塞卡滞。